Muscle nanostructure, fat colour related fatty acids and Check-All-That-Apply visual profiling of South African A2 beef longissimus
- Authors: Soji, Zimkhitha
- Date: 2019
- Subjects: Meat -- Quality
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15264 , vital:40332
- Description: The main objective of this study was to determine the effect of muscle nanostructure on tenderness, fat colour related fatty acids and Check-All-That-Apply visual profiling of South African A2 beef longissimus. Fifty two A-class steers (n=52) of five breeds (Bonsmara (n=19), Beef master (n=7), Hereford (n=9) and Simbra (n=17)) typically processed in different South African feedlots were studied. The animals were humanely slaughtered at an abattoir following the commercial standard procedures. Fat colour measurements (CIE b*) were taken at the P8 site on hot carcasses at the abattoir. Carcass mass (warm and cold) was recorded at the slaughter line before chilling (warm) and after chilling (cold) while pH0 and temperature were measured at 45 minutes post-mortem on the Longissimus thoracis et lumborum (LTL) muscle. Thereafter, a 20 g subsection of the LTL muscle on the left side of each carcass was sampled for muscle nanostructure analysis. At 24 hours post-slaughter, ultimate pH (pH24) was measured, further subsections of the LTL muscle (20 g) were harvested for further muscle nanostructure analysis and 2.5 kg of the LTL muscle was also harvested for analysis of tenderness, fatty acids and sensory evaluation. The muscle nanostructure (myofibril diameter (MYD), myofibril spacing (MYS), muscle fibre diameter (MFD), muscle fibre spacing (MFS) and sarcomere length (SL)) was analysed using the scanning electron microscope (SEM) while tenderness was measured using Warner Bratzler Shear Force after 45mins, 24hrs, 3 and 7 days aging period at -20 ºC refrigerator temperature. Some proximate fractions (total extractable intramuscular fat (Fat %), Fat Free Dry matter (FFDM %) and Moisture content) and fatty acid profile were measured using extracted fat and fatty acid indices (desaturase index, atherogenicity index) were calculated. Lastly a Check-All-That-Apply visual profiling method rated by an 80-member consumer panel was done to assess consumer meat preferences and perceptions of Bonsmara, Hereford and Simbra A2 fresh steaks. At 45mins post-slaughter breed affected (P<0.05) MYD and MYS, while at 24hrs breed affected MFD and MFS only. Early post-mortem pH (pH0) had no effect on the muscle nanostructure and tenderness while ultimate pH (pH24) affected MYD and MYS only. Muscle temperature at 45mins affected (P<0.05) the MYD, MFD and MFS, while 24hrs muscle temperature affected (P<0.05) MYD only. Tenderness was not related to the muscle nanostructure early post-mortem and there was no uniformity on the changes in muscle nanostructure and tenderness from early post-mortem to 24hrs against the multifaceted carcass mass, muscle pH and temperature effects. During ageing, breed affected the MYD and MYS at 45mins, while at 24hrs in addition to the myofibril structure breed also had an effect on muscle fibre bundle characteristics (MFD and MFS). The changes in MYD, MYS and MFS became constant on day 3 while variations in the MFD still progressed. There was no uniformity on the SL pattern during ageing and a very weak linear relationship between tenderness, SL, MFD and MFS was observed. Notably there was also no uniformity on how the muscle texture features; including the surface structure, fibre separation, and the mechanism of muscle contraction and relaxation; changed throughout the ageing period across and within the breeds. Moreover, breed had a significant effect on pentadecyclic acid, total saturated fatty acids (SFA) and docosahexanoic acid. Differences (P<0.05) in SFA, monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), n-6, n-3, fatty acid ratios, and desaturase index were observed among the white, creamy-white and creamy fat colour. The distribution of fatty acid classes was SFA>MUFA>PUFA in descending order of concentrations of mean values (44.19:40.06:15.75, respectively), while the n-6: n-3 ratio was 12:1. In sensory evaluation, consumers indicated how they would prefer to pay premium for meat with guaranteed muscle and fat colour, low fat content, high marbling and tenderness. Consumers observed breed differences (P<0.05) in muscle fibre separation and muscle colour. The overall liking of each attribute was more on moderate bright cherry red lean colour, moderate yellow fat, very abundant marbling and slight separation of muscle fibres. Differences on discrete liking of each attribute among consumers had an effect on the overall liking of each steak with Hereford steaks being more preferred by consumers. It was concluded that meat from beef animals within the same feeding regime has a different fatty acid composition owing to different breed synthetic pathways and feed ingredients and that meat tenderness is not affected by the muscle nanostructure early post-mortem. However, during ageing, meat tenderness is directly linked to breed related myofibril structure changes in particular the myofibril diameter, spacing between myofibrils and their interaction; while the muscle texture features, fibre diameter, spacing between muscle fibres and sarcomere length explain the non-uniformity of beef tenderness. Also the organoleptic and health related quality of meat assumed more importance among consumers in sensory evaluation. Thus meat classification systems should include more credence aspects or indicators that support credence quality of meat
- Full Text:
- Authors: Soji, Zimkhitha
- Date: 2019
- Subjects: Meat -- Quality
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15264 , vital:40332
- Description: The main objective of this study was to determine the effect of muscle nanostructure on tenderness, fat colour related fatty acids and Check-All-That-Apply visual profiling of South African A2 beef longissimus. Fifty two A-class steers (n=52) of five breeds (Bonsmara (n=19), Beef master (n=7), Hereford (n=9) and Simbra (n=17)) typically processed in different South African feedlots were studied. The animals were humanely slaughtered at an abattoir following the commercial standard procedures. Fat colour measurements (CIE b*) were taken at the P8 site on hot carcasses at the abattoir. Carcass mass (warm and cold) was recorded at the slaughter line before chilling (warm) and after chilling (cold) while pH0 and temperature were measured at 45 minutes post-mortem on the Longissimus thoracis et lumborum (LTL) muscle. Thereafter, a 20 g subsection of the LTL muscle on the left side of each carcass was sampled for muscle nanostructure analysis. At 24 hours post-slaughter, ultimate pH (pH24) was measured, further subsections of the LTL muscle (20 g) were harvested for further muscle nanostructure analysis and 2.5 kg of the LTL muscle was also harvested for analysis of tenderness, fatty acids and sensory evaluation. The muscle nanostructure (myofibril diameter (MYD), myofibril spacing (MYS), muscle fibre diameter (MFD), muscle fibre spacing (MFS) and sarcomere length (SL)) was analysed using the scanning electron microscope (SEM) while tenderness was measured using Warner Bratzler Shear Force after 45mins, 24hrs, 3 and 7 days aging period at -20 ºC refrigerator temperature. Some proximate fractions (total extractable intramuscular fat (Fat %), Fat Free Dry matter (FFDM %) and Moisture content) and fatty acid profile were measured using extracted fat and fatty acid indices (desaturase index, atherogenicity index) were calculated. Lastly a Check-All-That-Apply visual profiling method rated by an 80-member consumer panel was done to assess consumer meat preferences and perceptions of Bonsmara, Hereford and Simbra A2 fresh steaks. At 45mins post-slaughter breed affected (P<0.05) MYD and MYS, while at 24hrs breed affected MFD and MFS only. Early post-mortem pH (pH0) had no effect on the muscle nanostructure and tenderness while ultimate pH (pH24) affected MYD and MYS only. Muscle temperature at 45mins affected (P<0.05) the MYD, MFD and MFS, while 24hrs muscle temperature affected (P<0.05) MYD only. Tenderness was not related to the muscle nanostructure early post-mortem and there was no uniformity on the changes in muscle nanostructure and tenderness from early post-mortem to 24hrs against the multifaceted carcass mass, muscle pH and temperature effects. During ageing, breed affected the MYD and MYS at 45mins, while at 24hrs in addition to the myofibril structure breed also had an effect on muscle fibre bundle characteristics (MFD and MFS). The changes in MYD, MYS and MFS became constant on day 3 while variations in the MFD still progressed. There was no uniformity on the SL pattern during ageing and a very weak linear relationship between tenderness, SL, MFD and MFS was observed. Notably there was also no uniformity on how the muscle texture features; including the surface structure, fibre separation, and the mechanism of muscle contraction and relaxation; changed throughout the ageing period across and within the breeds. Moreover, breed had a significant effect on pentadecyclic acid, total saturated fatty acids (SFA) and docosahexanoic acid. Differences (P<0.05) in SFA, monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), n-6, n-3, fatty acid ratios, and desaturase index were observed among the white, creamy-white and creamy fat colour. The distribution of fatty acid classes was SFA>MUFA>PUFA in descending order of concentrations of mean values (44.19:40.06:15.75, respectively), while the n-6: n-3 ratio was 12:1. In sensory evaluation, consumers indicated how they would prefer to pay premium for meat with guaranteed muscle and fat colour, low fat content, high marbling and tenderness. Consumers observed breed differences (P<0.05) in muscle fibre separation and muscle colour. The overall liking of each attribute was more on moderate bright cherry red lean colour, moderate yellow fat, very abundant marbling and slight separation of muscle fibres. Differences on discrete liking of each attribute among consumers had an effect on the overall liking of each steak with Hereford steaks being more preferred by consumers. It was concluded that meat from beef animals within the same feeding regime has a different fatty acid composition owing to different breed synthetic pathways and feed ingredients and that meat tenderness is not affected by the muscle nanostructure early post-mortem. However, during ageing, meat tenderness is directly linked to breed related myofibril structure changes in particular the myofibril diameter, spacing between myofibrils and their interaction; while the muscle texture features, fibre diameter, spacing between muscle fibres and sarcomere length explain the non-uniformity of beef tenderness. Also the organoleptic and health related quality of meat assumed more importance among consumers in sensory evaluation. Thus meat classification systems should include more credence aspects or indicators that support credence quality of meat
- Full Text:
The effect of replacing antibiotic growth promoters with moringa oleifera leaf powder on growth performance, carcass characteristics, immune organ indices, gut microflora, physicochemical and sensory quality of broiler meat
- Nantapo, Carlos Wyson Tawanda
- Authors: Nantapo, Carlos Wyson Tawanda
- Date: 2018
- Subjects: Moringa oleifera Meat--Quality Broilers (Chickens)
- Language: English
- Type: Thesis , Doctoral , Animal Science
- Identifier: http://hdl.handle.net/10353/17749 , vital:41197
- Description: The objective of the study was to determine the effect of feeding graded levels of Moringa oleifera leaf meal powder (MOLP) on growth performance, carcass characteristics, economic analysis, health status, physicochemical, sensory properties, mineral composition and retention values of meat. A total of 1600 Comb-500 day-old unsexed chicks were allotted to 4 dietary treatment groups, with 4 replicate pens of 100 birds each in a completely randomised design. The dietary treatments were basal diets supplemented with different levels of MOLP as follows; Treatment 1/ control: Basal diet with antibiotic Zinc bacitracin and coccidiostatic Maxiban and no MOLP (0MOLP); Treatment 2: Basal diet included 1percent MOLP (1MOLP); Treatment 3: Basal diet included 3.0 percent MOLP (3MOLP); Treatment 4: Basal diet included 5 percent MOLP (5MOLP). Birds fed basal diets plus 5percent MOLP at starter phase achieved the least FCR 1.53 (P < 0.037), whilst consuming significantly less feed ADFI 47.4 g (P < 0.05). For the entire feeding period, birds fed 5 percent MOLP achieved a favourable FCR of 1.80 among all treatment groups (P < 0.001), but achieved the lowest final live weight (1416 g), carcass weights (1044g) (P < 0.05). Birds fed 0 percent MOLP recorded highest final weight, carcass weight (1339) and the best dressing percentages (76.8percent) (P < 0.05). Abdominal fat levels were reduced by elevating MOLP in diets (P < 0.05). Improvements in proportions of giblets, gizzard, liver and intestine were observed with increase in dietary MOLP. Feed costs increased, while gross and net returns and economic efficiency decreased as dietary MOLP increased. Organ indices of spleen, Bursa of Fabricius and liver were significantly increased by 5percent MOLP in the diet (P < 0.05). Macroscopic lesions scores (P < 0.05) were significantly higher in duodenum, jejunum and ileum of birds in the 1MOLP treatment group on d 28 and d 35. Control and 5MOLP groups recorded the least bloody excreta scores among all treatment groups (P < 0.05). Highest total aerobic bacteria (TAB), E. coli, C. perfringens counts and the lowest lactobacillus spp counts were observed in all intestinal segments in birds in the 1MOLP treatment group. Lower E. coli and C. perfringens but higher lactobacillus spp counts were observed in control and 5MOLP groups (P < 0.05) in the duodenum and jejunum. Increasing MOLP levels in diets led to lower pH and pHu in both breast and leg muscles (P < 0.05). pH was consistently lower in leg muscles than in breast cuts in all treatments and a large decline in post-mortem pH was observed in all muscles of birds in control group. A dietary increase in MOLP level led to a significant increase in L* and b* (P < 0.05) negative correlation between pH and L* (r = -0.463) (P < 0.05) and a weak but significant (P < 0.001) correlation (r = 0.176) between pH and drip loss. Herb flavour (P = 0.0029), appearance (P = 0.0156), aroma (P = 0.0011), colour (P = 0.0375), taste (P = 0.0032) and overall acceptability (P = 0.0192) were improved by grilling, microwave cooking and pan-frying in olive oil. These changes were more pronounced in breast muscle, thus following the trend; microwave > pan-frying in olive oil > grilled samples > boiling for best cooked product based on overall acceptability. Grilling and frying heart muscles resulted in the highest Ca (45.9 mg/kg) and Mg (98.9 mg/kg), whereas boiling led to the lowest Ca (41.1 mg/kg) and Mg (91.4 mg/kg) concentration. The highest concentrations of Fe and Zn these minerals were recorded in grilled (32.7 mg/kg) and fried samples (75.2 mg/kg). Zinc and Fe concentration observed in liver and heart muscles were higher than those found in breast and leg muscle. In conclusion, the results confirm the potential of MOLP for use as an alternative to antibiotics in maintaining broiler health, reducing mortalities and improving carcass characteristics and some meat quality traits.
- Full Text:
- Authors: Nantapo, Carlos Wyson Tawanda
- Date: 2018
- Subjects: Moringa oleifera Meat--Quality Broilers (Chickens)
- Language: English
- Type: Thesis , Doctoral , Animal Science
- Identifier: http://hdl.handle.net/10353/17749 , vital:41197
- Description: The objective of the study was to determine the effect of feeding graded levels of Moringa oleifera leaf meal powder (MOLP) on growth performance, carcass characteristics, economic analysis, health status, physicochemical, sensory properties, mineral composition and retention values of meat. A total of 1600 Comb-500 day-old unsexed chicks were allotted to 4 dietary treatment groups, with 4 replicate pens of 100 birds each in a completely randomised design. The dietary treatments were basal diets supplemented with different levels of MOLP as follows; Treatment 1/ control: Basal diet with antibiotic Zinc bacitracin and coccidiostatic Maxiban and no MOLP (0MOLP); Treatment 2: Basal diet included 1percent MOLP (1MOLP); Treatment 3: Basal diet included 3.0 percent MOLP (3MOLP); Treatment 4: Basal diet included 5 percent MOLP (5MOLP). Birds fed basal diets plus 5percent MOLP at starter phase achieved the least FCR 1.53 (P < 0.037), whilst consuming significantly less feed ADFI 47.4 g (P < 0.05). For the entire feeding period, birds fed 5 percent MOLP achieved a favourable FCR of 1.80 among all treatment groups (P < 0.001), but achieved the lowest final live weight (1416 g), carcass weights (1044g) (P < 0.05). Birds fed 0 percent MOLP recorded highest final weight, carcass weight (1339) and the best dressing percentages (76.8percent) (P < 0.05). Abdominal fat levels were reduced by elevating MOLP in diets (P < 0.05). Improvements in proportions of giblets, gizzard, liver and intestine were observed with increase in dietary MOLP. Feed costs increased, while gross and net returns and economic efficiency decreased as dietary MOLP increased. Organ indices of spleen, Bursa of Fabricius and liver were significantly increased by 5percent MOLP in the diet (P < 0.05). Macroscopic lesions scores (P < 0.05) were significantly higher in duodenum, jejunum and ileum of birds in the 1MOLP treatment group on d 28 and d 35. Control and 5MOLP groups recorded the least bloody excreta scores among all treatment groups (P < 0.05). Highest total aerobic bacteria (TAB), E. coli, C. perfringens counts and the lowest lactobacillus spp counts were observed in all intestinal segments in birds in the 1MOLP treatment group. Lower E. coli and C. perfringens but higher lactobacillus spp counts were observed in control and 5MOLP groups (P < 0.05) in the duodenum and jejunum. Increasing MOLP levels in diets led to lower pH and pHu in both breast and leg muscles (P < 0.05). pH was consistently lower in leg muscles than in breast cuts in all treatments and a large decline in post-mortem pH was observed in all muscles of birds in control group. A dietary increase in MOLP level led to a significant increase in L* and b* (P < 0.05) negative correlation between pH and L* (r = -0.463) (P < 0.05) and a weak but significant (P < 0.001) correlation (r = 0.176) between pH and drip loss. Herb flavour (P = 0.0029), appearance (P = 0.0156), aroma (P = 0.0011), colour (P = 0.0375), taste (P = 0.0032) and overall acceptability (P = 0.0192) were improved by grilling, microwave cooking and pan-frying in olive oil. These changes were more pronounced in breast muscle, thus following the trend; microwave > pan-frying in olive oil > grilled samples > boiling for best cooked product based on overall acceptability. Grilling and frying heart muscles resulted in the highest Ca (45.9 mg/kg) and Mg (98.9 mg/kg), whereas boiling led to the lowest Ca (41.1 mg/kg) and Mg (91.4 mg/kg) concentration. The highest concentrations of Fe and Zn these minerals were recorded in grilled (32.7 mg/kg) and fried samples (75.2 mg/kg). Zinc and Fe concentration observed in liver and heart muscles were higher than those found in breast and leg muscle. In conclusion, the results confirm the potential of MOLP for use as an alternative to antibiotics in maintaining broiler health, reducing mortalities and improving carcass characteristics and some meat quality traits.
- Full Text:
Effects of Vigna unguiculata and Lablab purpureus on methanogenesis, haematological parameters and the quality of meat from Xhosa Lop Ear goats
- Authors: Washaya, Soul
- Date: 2017
- Subjects: Legumes Forage Forage plants
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/9996 , vital:35249
- Description: The objective of the current study was to evaluate the nutritive value of forage legumes Lablab purpureus (Lablab) and Vigna unguiculata (Cowpea) and their effects on intake, growth, blood parameters and meat quality in Xhosa goats. Forages were established at UFH research farm in the summer of the 2014 /15 growing season in blocks measuring 8m width x 16m long for each legume, replicated three times, making a total of four blocks, and eight treatment units for each legume. Samples were collected at three different stages of growth of preanthesis, anthesis and post anthesis for biomass yield determination. A homogenous sub-sample was then oven dried for 72 hours at 60 0C. After drying the forage samples were milled through a 1mm screen and a 20g sample from each stage of growth and forage sample was subjected to proximate analysis, in-vitro digestibility and anti-nutrient evaluation. The in-vitro digestibility experiment was done with rumen liquor of cattle and sheep collected from an abbatoir. Tannins, total phenolics and sapponins were the only anti-nutrients evaluated as they are perceived to influence methanogenesis in ruminat animals. At 50percent flowering, forage legumes were harvested for hay making which was then used in an in-vivo trial to evaluate the nutritive value of forages. This trial was conducted using eighteen one-year-old goats of average weight 14.2±0.24 kg over a period of sixty days. The results showed that biomass yield, which increased with stage of growth, was significantly higher (P < 0.05) for Lablab than Cowpea (7.968t/ha vs 7.105t/ha). Cowpea exhibited higher moisture content (7.72percent), Ash (13.11percent), acid detergent fibre (ADF) (38.42percent) and crude protein (CP) (20.23percent) than Lablab which had 7.50percent, 11.45 percent, 36.17percent and 19percent, respectively. Lablab forage had significantly higher (P < 0.05) fat content (2.41percent), neutral detergent fibre (NDF) (49.27percent) and hemicellulose (13.07percent) than Cowpea which had 2.1percent; 46.91percent and 8.48percent, respectively. The stage of growth significantly (P < 0.05) affected the mineral content of both forages. Lablab showed significantly higher (P < 0.05) values (1.22percent 0.55percent, 2.67percent) than Cowpea (1.00percent, 0.45percent, 2.30percent) for calcium (Ca), phosphorus (P), and potassium (K) respectively. Lablab forage had significantly higher (P < 0.05) tannin (3.345mgCAE/gDM), phenolic (13.47mgGAE/gDM) and saponin (0.75percent) content compared to Cowpea with values of 1.494mgCAEg/DM; 9.402mgGAE/gDM and vs 1.55percent respectively. The tannin content significantly influenced in-vitro digestibility and enteric methane production. The forage type, harvesting stage and inoculum source significantly (P < 0.05) affected the in-vitro digestibility of the forages. The in-vitro dry matter (IVDM) and in-vitro organic matter (IVOM) digestibility was significantly higher (P < 0.05) for Lablab (41.13percent; 39.63percent) than Cowpea (39.86percent; 19.44percent), respectively. Both forages recorded higher dry matter (DM) digestibility coefficients at anthesis stage of growth 61.58percent, and 51.5 percent for Lablab and Cowpea respectively. The IVOM digestibility increased with stage of harvest (23.7percent to 25.57percent) for Cowpea while Lablab showed a decrease (44.6 percent to 43.9percent) when cattle inoculum was used. The IVDM digestibility was higher (P < 0.05) for Lablab (50.5percent) when cattle inoculum was used while Cowpea was observed to have higher digestibility co-efficiencies (38.54percent) when sheep inoculum was used. Cowpea had lower (P < 0.05) IVOM digestibility than Lablab (19.44percent) vs. 39.6percent). Lablab exhibited higher (P < 0.05) metabolisable energy (ME) values than Cowpea (6.21 vs. 2.70 MJ/kgDM). In the feeding study, the total DM intake by goats for Lablab was higher (P < 0.05) compared to Cowpea (688.1 vs. 607.8 g/head/ day). There was a positive (P < 0.05) correlation between dry matter intake and average daily gain (r= 0.8513, and r=0.5279) for Cowpea and Lablab respectively. Lablab and Cowpea promoted growth of Xhosa goats at a rate of 35.0g/d; and 38.3g/d, respectively which was not significantly different (P > 0.05). However, this growth was associated with a significantly higher (P < 0.05) food conversion ratio (FCR) of 19.16 vs 18.11 for Cowpea and Lablab, respectively. The apparent DM, non structural carbohydrate (NSC) nutrient digestibilities were significantly different (P < 0.05) for Lablab and Cowpea. Furthermore sex of animal influenced significantly (P < 0.05) the DM, ADF, NSC and NDF digestibilities. Lablab and Cowpea did not influence (P > 0.05) individual VFA molar concentrations in both sexes. However, animals fed Lablab had significantly higher butyrate concentrations (P < 0.05). Lablab and Cowpea forages significantly lowered (P > 0.05) enteric methane production in goats compared to a concentrate diet, and this was related to animal activity. Animals produced significantly more (P < 0.05) methane gas when ruminating than feeding or just standing. The average methane produced each year was lower but not significant (P > 0.05) for animals fed Cowpea than Lablab (4.602kg CH4, vs. 4.719kg CH4) when expressed per year. Male animals produced more gas than females with values of 17.40L/day; 12.46 g/kg DMI and 0.126g/day vs. 15.47L/day, 12.28 g/kg DMI, and 0.0109g/day, respectively. Forage legumes had no significant effects (P > 0.05) on serum total proteins (TP), globulin, urea, creatinine, alanine aminotransferase (ALT), alkaline phosphatase (ALP), and gamma- glutamyl transferase (GGT) concentrations, but serum concentration of albumin was influenced by the diets (P < 0.05). Sex of animals significantly influenced ALP concentration (P < 0.05) with male animals exhibiting higer ALP values than females. Measured over time, the plasma concentration of urea and ALP significantly increased (P < 0.05) while creatinine and cholesterol concentration decreased (P < 0.05). Although the overall serum concentration of urea, total proteins, globulin, creatinine, ALT, ALP and GGT remained unchanged among the treatments and between sexes; treatment by sex, treatment by day and sex by day interactions were significant (P < 0.05). The white blood cell (WBC), red blood cell (RBC), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), haemoglobin, haematocrite, platelet and mean platelet volume (MPV) levels were similar among treatments and between sexes (P > 0.05). The WBC decreased with time by 8.07 x10 9/l while mean crepuscular volume (MCV) increased by 11.83(fl) from day 15 to day 55. Treatment diets significantly (P < 0.05) influenced neutrophile (percent) content while sex influenced basophile (percent) content. There were no treatment or sex effects (P > 0.05) on lymphocytes (percent), monocytes (percent) and eosinophiles (percent). In the meat quality study, the dietary treatments and sex had a significant (P < 0.05) effect on dressing out percent (DPpercent), initial pH, redness (a*), yellowness (b*), Warner Blartze Shear force (WBS) , drip loss and cooking loss in the chevon from Xhosa goats. Compared with a commercial pellet diet, Lablab and Cowpea diets resulted in similar slaughter body weights (SBW), hot carcass weight (HCW) and cold dressed mass (CDM) of carcasses. However, female animals exhibited a significantly (P < 0.05) higher DPpercent than male animals (42.3percent vs. 38.9percent) for all treatments. The male animals exhibited significantly (P < 0.05) higher pH values one hour after slaughter than females (5.79 vs 5.67). Neverthreless the diet and gender did not significantly (P > 0.05) affect the ultimate pH (pHu). Meat samples from male animals had significantly (P < 0.05) higher redness values than females. Feeding cowpea significantly (P < 0.05) increased meat redness with the least drip loss of chevon. Female animals produced significantly (P < 0.05) tougher chevon compared to male animals; 4.16kg and 3.36kg for female and male, respectively. Lablab and Cowpea posses high CP levels and moderately lower NDF with high ADF values that influences dry matter intake (DMI), digestibility and growth of goats. These forage legumes meet animal requirements for fat, ADF, NDF, CP, Ca, Mn, zinc and Cu and their biomass yield is satisfactory.
- Full Text:
- Authors: Washaya, Soul
- Date: 2017
- Subjects: Legumes Forage Forage plants
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/9996 , vital:35249
- Description: The objective of the current study was to evaluate the nutritive value of forage legumes Lablab purpureus (Lablab) and Vigna unguiculata (Cowpea) and their effects on intake, growth, blood parameters and meat quality in Xhosa goats. Forages were established at UFH research farm in the summer of the 2014 /15 growing season in blocks measuring 8m width x 16m long for each legume, replicated three times, making a total of four blocks, and eight treatment units for each legume. Samples were collected at three different stages of growth of preanthesis, anthesis and post anthesis for biomass yield determination. A homogenous sub-sample was then oven dried for 72 hours at 60 0C. After drying the forage samples were milled through a 1mm screen and a 20g sample from each stage of growth and forage sample was subjected to proximate analysis, in-vitro digestibility and anti-nutrient evaluation. The in-vitro digestibility experiment was done with rumen liquor of cattle and sheep collected from an abbatoir. Tannins, total phenolics and sapponins were the only anti-nutrients evaluated as they are perceived to influence methanogenesis in ruminat animals. At 50percent flowering, forage legumes were harvested for hay making which was then used in an in-vivo trial to evaluate the nutritive value of forages. This trial was conducted using eighteen one-year-old goats of average weight 14.2±0.24 kg over a period of sixty days. The results showed that biomass yield, which increased with stage of growth, was significantly higher (P < 0.05) for Lablab than Cowpea (7.968t/ha vs 7.105t/ha). Cowpea exhibited higher moisture content (7.72percent), Ash (13.11percent), acid detergent fibre (ADF) (38.42percent) and crude protein (CP) (20.23percent) than Lablab which had 7.50percent, 11.45 percent, 36.17percent and 19percent, respectively. Lablab forage had significantly higher (P < 0.05) fat content (2.41percent), neutral detergent fibre (NDF) (49.27percent) and hemicellulose (13.07percent) than Cowpea which had 2.1percent; 46.91percent and 8.48percent, respectively. The stage of growth significantly (P < 0.05) affected the mineral content of both forages. Lablab showed significantly higher (P < 0.05) values (1.22percent 0.55percent, 2.67percent) than Cowpea (1.00percent, 0.45percent, 2.30percent) for calcium (Ca), phosphorus (P), and potassium (K) respectively. Lablab forage had significantly higher (P < 0.05) tannin (3.345mgCAE/gDM), phenolic (13.47mgGAE/gDM) and saponin (0.75percent) content compared to Cowpea with values of 1.494mgCAEg/DM; 9.402mgGAE/gDM and vs 1.55percent respectively. The tannin content significantly influenced in-vitro digestibility and enteric methane production. The forage type, harvesting stage and inoculum source significantly (P < 0.05) affected the in-vitro digestibility of the forages. The in-vitro dry matter (IVDM) and in-vitro organic matter (IVOM) digestibility was significantly higher (P < 0.05) for Lablab (41.13percent; 39.63percent) than Cowpea (39.86percent; 19.44percent), respectively. Both forages recorded higher dry matter (DM) digestibility coefficients at anthesis stage of growth 61.58percent, and 51.5 percent for Lablab and Cowpea respectively. The IVOM digestibility increased with stage of harvest (23.7percent to 25.57percent) for Cowpea while Lablab showed a decrease (44.6 percent to 43.9percent) when cattle inoculum was used. The IVDM digestibility was higher (P < 0.05) for Lablab (50.5percent) when cattle inoculum was used while Cowpea was observed to have higher digestibility co-efficiencies (38.54percent) when sheep inoculum was used. Cowpea had lower (P < 0.05) IVOM digestibility than Lablab (19.44percent) vs. 39.6percent). Lablab exhibited higher (P < 0.05) metabolisable energy (ME) values than Cowpea (6.21 vs. 2.70 MJ/kgDM). In the feeding study, the total DM intake by goats for Lablab was higher (P < 0.05) compared to Cowpea (688.1 vs. 607.8 g/head/ day). There was a positive (P < 0.05) correlation between dry matter intake and average daily gain (r= 0.8513, and r=0.5279) for Cowpea and Lablab respectively. Lablab and Cowpea promoted growth of Xhosa goats at a rate of 35.0g/d; and 38.3g/d, respectively which was not significantly different (P > 0.05). However, this growth was associated with a significantly higher (P < 0.05) food conversion ratio (FCR) of 19.16 vs 18.11 for Cowpea and Lablab, respectively. The apparent DM, non structural carbohydrate (NSC) nutrient digestibilities were significantly different (P < 0.05) for Lablab and Cowpea. Furthermore sex of animal influenced significantly (P < 0.05) the DM, ADF, NSC and NDF digestibilities. Lablab and Cowpea did not influence (P > 0.05) individual VFA molar concentrations in both sexes. However, animals fed Lablab had significantly higher butyrate concentrations (P < 0.05). Lablab and Cowpea forages significantly lowered (P > 0.05) enteric methane production in goats compared to a concentrate diet, and this was related to animal activity. Animals produced significantly more (P < 0.05) methane gas when ruminating than feeding or just standing. The average methane produced each year was lower but not significant (P > 0.05) for animals fed Cowpea than Lablab (4.602kg CH4, vs. 4.719kg CH4) when expressed per year. Male animals produced more gas than females with values of 17.40L/day; 12.46 g/kg DMI and 0.126g/day vs. 15.47L/day, 12.28 g/kg DMI, and 0.0109g/day, respectively. Forage legumes had no significant effects (P > 0.05) on serum total proteins (TP), globulin, urea, creatinine, alanine aminotransferase (ALT), alkaline phosphatase (ALP), and gamma- glutamyl transferase (GGT) concentrations, but serum concentration of albumin was influenced by the diets (P < 0.05). Sex of animals significantly influenced ALP concentration (P < 0.05) with male animals exhibiting higer ALP values than females. Measured over time, the plasma concentration of urea and ALP significantly increased (P < 0.05) while creatinine and cholesterol concentration decreased (P < 0.05). Although the overall serum concentration of urea, total proteins, globulin, creatinine, ALT, ALP and GGT remained unchanged among the treatments and between sexes; treatment by sex, treatment by day and sex by day interactions were significant (P < 0.05). The white blood cell (WBC), red blood cell (RBC), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), haemoglobin, haematocrite, platelet and mean platelet volume (MPV) levels were similar among treatments and between sexes (P > 0.05). The WBC decreased with time by 8.07 x10 9/l while mean crepuscular volume (MCV) increased by 11.83(fl) from day 15 to day 55. Treatment diets significantly (P < 0.05) influenced neutrophile (percent) content while sex influenced basophile (percent) content. There were no treatment or sex effects (P > 0.05) on lymphocytes (percent), monocytes (percent) and eosinophiles (percent). In the meat quality study, the dietary treatments and sex had a significant (P < 0.05) effect on dressing out percent (DPpercent), initial pH, redness (a*), yellowness (b*), Warner Blartze Shear force (WBS) , drip loss and cooking loss in the chevon from Xhosa goats. Compared with a commercial pellet diet, Lablab and Cowpea diets resulted in similar slaughter body weights (SBW), hot carcass weight (HCW) and cold dressed mass (CDM) of carcasses. However, female animals exhibited a significantly (P < 0.05) higher DPpercent than male animals (42.3percent vs. 38.9percent) for all treatments. The male animals exhibited significantly (P < 0.05) higher pH values one hour after slaughter than females (5.79 vs 5.67). Neverthreless the diet and gender did not significantly (P > 0.05) affect the ultimate pH (pHu). Meat samples from male animals had significantly (P < 0.05) higher redness values than females. Feeding cowpea significantly (P < 0.05) increased meat redness with the least drip loss of chevon. Female animals produced significantly (P < 0.05) tougher chevon compared to male animals; 4.16kg and 3.36kg for female and male, respectively. Lablab and Cowpea posses high CP levels and moderately lower NDF with high ADF values that influences dry matter intake (DMI), digestibility and growth of goats. These forage legumes meet animal requirements for fat, ADF, NDF, CP, Ca, Mn, zinc and Cu and their biomass yield is satisfactory.
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Adaptive responses to heat stress, quality of hide and meat from indigenous Nguni and non-descript crossbred cattle
- Authors: Chikwanda, Denice
- Date: 2016
- Subjects: Cattle -- Effect of temperature on Nguni cattle Beef cattle breeds
- Language: English
- Type: Thesis , Doctoral , PhD (Agriculture)
- Identifier: http://hdl.handle.net/10353/10614 , vital:35635
- Description: The main objective of this study was to determine the adaptive responses of Nguni and non-descript crossbred cattle (NDCC) to heat stress, nutritionally-related blood metabolite profiles, fatty acid profiles, carcass and meat characteristics, physico-mechanical properties of automotive upholstery crust leather and the associated collagen fibre architecture of hides and crust leather. Forty steers (20 Nguni and 20 NDCC) which were approximately 14 months of age with live weights ranging between 153 kg and 203 kg at the beginning of the study were used. Environmental variables (ambient temperature, relative humidity, wind parameters, solar radiation) were collected from a weather station at the research farm. Temperature-humidity index (THI) values were computed. Rectal and skin temperature, skin traits and blood metabolites were determined at two-week intervals over 16 weeks. Hair coat scores ranged from extremely short (score 1) to very woolly (score 7). At slaughter, blood samples were collected after exsanguination. Meat samples were collected from the right muscularis longissimus thoracis et lumborum (LTL) and Triceps brachii (TB) muscles after 24 hours of chilling of carcasses for physico-chemical quality tests. Fatty acid profiles and physico-chemical quality of meat were determined on the LTL and TB. An additional fifty-four hides (27 Nguni and 27 NDCC) were obtained from a commercial abattoir at slaughter. The hides were tanned into automotive crust leather and tested for physico-mechanical quality. Results showed that week and environmental variables affected skin temperature; also, the rectal and skin temperatures were negatively correlated to body condition, skin pigment, coat score and skin thickness. Non-descript crossbred cattle had higher coat scores (2.1 ± 0.36 to 4.1 ± 4.20) than Nguni cattle (1.6 ± 0.36 to 4.1 ± 0.36). Body condition scores, blood creatinine, urea, total protein, albumin and globulin were affected by genotype and week of sampling. At the end of the trial, NDCC had higher slaughter and hide weights (285.9 ± 6.52 kg and 18.4 ± 0.54 kg, respectively) than Nguni cattle (232.6 ± 6.5 kg and 14.7 ± 0.54 kg, respectively). The majority of NDCC carcasses (73.7 percent) had a fatness level of 1 compared to Nguni carcasses (50 percent). Intramuscular fat was higher in Nguni (1.8 ± 0.09 percent) compared to NDCC (1.5 ± 0.09 percent) steers. Nguni steers had darker muscle colour (L*=33.6 ± 0.01) than NDCC (L*= 35.7 ± 0.54). Nguni and NDCC had similar thawing loss, cooking loss, WBSF tenderness, fat-free dry matter, moisture content, fatty acid profiles and health-related lipid indices. Ultimate muscle pH, meat colour and chroma were similar in the LTL and TB. Concerning the skin, Nguni and NDCC had similar physico-mechanical properties. However, breaking load and tensile strength were higher (1257.1 ± 70.72 N and 28.3 ± 1.23 MPa) in samples taken parallel to the backbone compared to that taken perpendicular to the backbone (979.5 ±70.72 N and 23.6 ±1.23MPa) across the two genotypes. Non-descript crossbred crust leather varied in physico-mechanical tests by direction of sampling. Collagen fibre orientation in hides and crust samples also varied between longitudinal and cross-sections. Collagen fibre diameters in the Nguni were similar in longitudinal and cross-sections (3.4 ± 0.12 μm and 3.2 ± 0.11 μm, respectively). From this study, it is concluded that THI, hair coat, skin traits and body condition affect skin temperature, but not rectal temperature, cortisol and CK activity in Nguni and NDCC reared extensively. The two genotypes differ in nutritionally-related blood metabolites, growth performance, hide weights and carcass traits. Beef from Nguni and NDCC differs in the IMF and meat lightness but is similar in the meat fatty acid composition and some physico-chemical quality parameters. Automotive crust leathers from the two genotypes were similar in some physico-mechanical properties. Collagen architecture varied among different regions of hides and crust leathers
- Full Text:
- Authors: Chikwanda, Denice
- Date: 2016
- Subjects: Cattle -- Effect of temperature on Nguni cattle Beef cattle breeds
- Language: English
- Type: Thesis , Doctoral , PhD (Agriculture)
- Identifier: http://hdl.handle.net/10353/10614 , vital:35635
- Description: The main objective of this study was to determine the adaptive responses of Nguni and non-descript crossbred cattle (NDCC) to heat stress, nutritionally-related blood metabolite profiles, fatty acid profiles, carcass and meat characteristics, physico-mechanical properties of automotive upholstery crust leather and the associated collagen fibre architecture of hides and crust leather. Forty steers (20 Nguni and 20 NDCC) which were approximately 14 months of age with live weights ranging between 153 kg and 203 kg at the beginning of the study were used. Environmental variables (ambient temperature, relative humidity, wind parameters, solar radiation) were collected from a weather station at the research farm. Temperature-humidity index (THI) values were computed. Rectal and skin temperature, skin traits and blood metabolites were determined at two-week intervals over 16 weeks. Hair coat scores ranged from extremely short (score 1) to very woolly (score 7). At slaughter, blood samples were collected after exsanguination. Meat samples were collected from the right muscularis longissimus thoracis et lumborum (LTL) and Triceps brachii (TB) muscles after 24 hours of chilling of carcasses for physico-chemical quality tests. Fatty acid profiles and physico-chemical quality of meat were determined on the LTL and TB. An additional fifty-four hides (27 Nguni and 27 NDCC) were obtained from a commercial abattoir at slaughter. The hides were tanned into automotive crust leather and tested for physico-mechanical quality. Results showed that week and environmental variables affected skin temperature; also, the rectal and skin temperatures were negatively correlated to body condition, skin pigment, coat score and skin thickness. Non-descript crossbred cattle had higher coat scores (2.1 ± 0.36 to 4.1 ± 4.20) than Nguni cattle (1.6 ± 0.36 to 4.1 ± 0.36). Body condition scores, blood creatinine, urea, total protein, albumin and globulin were affected by genotype and week of sampling. At the end of the trial, NDCC had higher slaughter and hide weights (285.9 ± 6.52 kg and 18.4 ± 0.54 kg, respectively) than Nguni cattle (232.6 ± 6.5 kg and 14.7 ± 0.54 kg, respectively). The majority of NDCC carcasses (73.7 percent) had a fatness level of 1 compared to Nguni carcasses (50 percent). Intramuscular fat was higher in Nguni (1.8 ± 0.09 percent) compared to NDCC (1.5 ± 0.09 percent) steers. Nguni steers had darker muscle colour (L*=33.6 ± 0.01) than NDCC (L*= 35.7 ± 0.54). Nguni and NDCC had similar thawing loss, cooking loss, WBSF tenderness, fat-free dry matter, moisture content, fatty acid profiles and health-related lipid indices. Ultimate muscle pH, meat colour and chroma were similar in the LTL and TB. Concerning the skin, Nguni and NDCC had similar physico-mechanical properties. However, breaking load and tensile strength were higher (1257.1 ± 70.72 N and 28.3 ± 1.23 MPa) in samples taken parallel to the backbone compared to that taken perpendicular to the backbone (979.5 ±70.72 N and 23.6 ±1.23MPa) across the two genotypes. Non-descript crossbred crust leather varied in physico-mechanical tests by direction of sampling. Collagen fibre orientation in hides and crust samples also varied between longitudinal and cross-sections. Collagen fibre diameters in the Nguni were similar in longitudinal and cross-sections (3.4 ± 0.12 μm and 3.2 ± 0.11 μm, respectively). From this study, it is concluded that THI, hair coat, skin traits and body condition affect skin temperature, but not rectal temperature, cortisol and CK activity in Nguni and NDCC reared extensively. The two genotypes differ in nutritionally-related blood metabolites, growth performance, hide weights and carcass traits. Beef from Nguni and NDCC differs in the IMF and meat lightness but is similar in the meat fatty acid composition and some physico-chemical quality parameters. Automotive crust leathers from the two genotypes were similar in some physico-mechanical properties. Collagen architecture varied among different regions of hides and crust leathers
- Full Text:
Effects of grazing and housing management systems on greenhouse gas emissions, blood profiles and meat quality of Nguni goats
- Authors: Tapiwa, Chikwanda Allen
- Date: 2016
- Subjects: Goats Goats -- Feeding and feeds Greenhouse gas mitigation , Grazing -- Environmental aspects
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/2314 , vital:27752
- Description: The broad objective of this study was to evaluate the effects of grazing and housing management systems on greenhouse gas emissions, blood profiles and meat quality of Nguni goats. A total of 64 castrated Nguni goats were used and a housing structure was designed to accommodate the goats as well as evaluate effects of type of floor on greenhouse gases, meat quality, blood metabolites and fatty acid profiles. In the first experiment: Forty-eight castrated Nguni goats, at 6-7 months old were used for herding (H) or tethering (T) management systems and randomly allocated to pens with earth (E) or slatted (S) floors. Gas sampling was done using static chambers and analysed using a SRI 8610C gas chromatography machine. The highest CH4 fluxes were from the manure of herded goats on earth floors (HE). The highest CO2 fluxes were from manure of herded goats that were housed on slatted floors (HS): The highest N2O fluxes were from the manure of tethered goats that were sheltered on slatted floors (TS). It was concluded from the first experiment that goat manure is an important source of GHG that is influenced by grazing and floor type management systems. The second experiment was done to evaluate greenhouse gas (GHG) emission from disused (DP) vs occupied goat pens (OP) with earth (EF) or slatted (SF) floors. Eight previously occupied pens were used in this study. Sixteen goats were randomly put in the pens labelled occupied pens with earth floors (OPEF) and occupied pens with slatted floors (OPSF) resulting in four goats per OP. There were month by pen use; month by floor type; and use by floor type interaction effects (P < 0.05) on CH4 production. Floor type, use (DP vs OP) and month affected (P < 0.05) CH4 production. Manure on earth floors of occupied pens (OPEF) emitted the highest (P < 0.05) methane followed by earth floors of disused pens (DPEF). The least CH4 was emitted from DPSF. There was pen use (DP vs OP) by floor type interaction effect (P < 0.05) on CO2 emission. Floor type and pen use affected (P < 0.05) CO2 production. Manure in occupied pens with slatted floors (OPSF) produced the highest CO2 and the least CO2 was from disused pens with slatted floors (DPSF). Floor type and month influenced (P < 0.05) N2O production. It was concluded that continued use of goat pens increased GHG emissions. However, disused goat pens with manure remain an important source of GHG as they continued to emit quantifiable levels of CH4, CO2 and N2O. The third experiment was done to determine the effects of grazing and housing management systems on the concentrations of blood metabolites, activity of creatine kinase, body weight (BW), body condition score (BCS) and carcass characteristics using 48 castrated Nguni goats. Tethered goats had higher (P<0.05): urea, creatinine, total protein, globulin concentrations and more activity of CK than herded goats. On the other hand, herded goats had higher (P<0.05) plasma glucose (H: 3.39±0.020 vs T: 3.23±0.020 mmol/L), serum albumin (H: 15.30±0.147 vs T: 14.82±0.144 g/L) concentration. It was concluded that serum concentrations of all the metabolites and the activity of CK were sensitive to grazing system. Herding of goats promoted more glucose concentration and preservation of muscle protein and hence superior body weights and BCS than tethered goats. The fourth experiment was done to determine the effects of grazing and housing management systems on the activity of creatine kinase (CK) and cortisol concentration, and chevon quality. Further, the effect of muscle type [Muscularis longissimus thoracis et. Lumborum (LTL) and triceps brachii (TB)] on chevon quality was also investigated. Forty eight castrated Nguni goats aged 6- 7 months were randomly allocated to tethering (n=24) and herding (n=24) treatments. Floor type affected meat (P<0.05) pH24. Tethered goats had higher (P < 0.05) L* and CL percent than herded goats. Muscle type had a significant influence (P < 0.05) on a*, WBSF and pH. It was observed and concluded that T resulted in higher L* and more CL percent whilst SF lowered the pH24 of chevon; at the same time meat from the TB muscle was more tender, despite having a higher pH24 and more CL percent relative to LTH cuts. The fifth experiment was done to determine the effect of grazing and floor type on fatty acid composition of chevon from tethered and herded Nguni goats. Floor type had no effect on fatty acid composition. Oleic, stearic, palmitic and linoleic were the major fatty acids. Chevon from tethered goats had higher (P < 0.05) proportions of long chain polyunsaturated fatty acids (PUFAs): eicosapentaenoic, docosapentaenoic, docosahexaenoic, conjugated linoleic acid (CLA) and more total SFA, total PUFA, total Omega- 6 and total omega 3 fatty acids than herded goats. On the other hand, chevon from herded goats had more (P < 0.05) C18:1c9, C18:2t9, 12 (n-6), C20:3c11, 14, 17 (n-3) and total MUFA than tethered goats. However, there was no difference (P > 0.05) in the PUFA: SFA and n-6/n-3 fatty acid ratios between the herded and tethered goats. It was concluded that tethering promoted higher proportions of beneficial PUFAs which were more in TB than LTH muscle. The overall conclusions from the whole study were that goat manure is an important source of GHG with high CH4 being emitted from earth floors of herded goats. High CO2 and N2O are emitted from SF of herded and tethered goats, respectively. There were no major differences in meat quality between herded and tethered goats. However, herding promoted more live weight gain than tethering. On the other hand, tethering promoted more beneficial fatty acids. Therefore depending on the objective of the enterprise, smallholder farmers can safely tether or herd their goats. Further, there is need to develop technologies to harness CH4 from goat manure.
- Full Text:
- Authors: Tapiwa, Chikwanda Allen
- Date: 2016
- Subjects: Goats Goats -- Feeding and feeds Greenhouse gas mitigation , Grazing -- Environmental aspects
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/2314 , vital:27752
- Description: The broad objective of this study was to evaluate the effects of grazing and housing management systems on greenhouse gas emissions, blood profiles and meat quality of Nguni goats. A total of 64 castrated Nguni goats were used and a housing structure was designed to accommodate the goats as well as evaluate effects of type of floor on greenhouse gases, meat quality, blood metabolites and fatty acid profiles. In the first experiment: Forty-eight castrated Nguni goats, at 6-7 months old were used for herding (H) or tethering (T) management systems and randomly allocated to pens with earth (E) or slatted (S) floors. Gas sampling was done using static chambers and analysed using a SRI 8610C gas chromatography machine. The highest CH4 fluxes were from the manure of herded goats on earth floors (HE). The highest CO2 fluxes were from manure of herded goats that were housed on slatted floors (HS): The highest N2O fluxes were from the manure of tethered goats that were sheltered on slatted floors (TS). It was concluded from the first experiment that goat manure is an important source of GHG that is influenced by grazing and floor type management systems. The second experiment was done to evaluate greenhouse gas (GHG) emission from disused (DP) vs occupied goat pens (OP) with earth (EF) or slatted (SF) floors. Eight previously occupied pens were used in this study. Sixteen goats were randomly put in the pens labelled occupied pens with earth floors (OPEF) and occupied pens with slatted floors (OPSF) resulting in four goats per OP. There were month by pen use; month by floor type; and use by floor type interaction effects (P < 0.05) on CH4 production. Floor type, use (DP vs OP) and month affected (P < 0.05) CH4 production. Manure on earth floors of occupied pens (OPEF) emitted the highest (P < 0.05) methane followed by earth floors of disused pens (DPEF). The least CH4 was emitted from DPSF. There was pen use (DP vs OP) by floor type interaction effect (P < 0.05) on CO2 emission. Floor type and pen use affected (P < 0.05) CO2 production. Manure in occupied pens with slatted floors (OPSF) produced the highest CO2 and the least CO2 was from disused pens with slatted floors (DPSF). Floor type and month influenced (P < 0.05) N2O production. It was concluded that continued use of goat pens increased GHG emissions. However, disused goat pens with manure remain an important source of GHG as they continued to emit quantifiable levels of CH4, CO2 and N2O. The third experiment was done to determine the effects of grazing and housing management systems on the concentrations of blood metabolites, activity of creatine kinase, body weight (BW), body condition score (BCS) and carcass characteristics using 48 castrated Nguni goats. Tethered goats had higher (P<0.05): urea, creatinine, total protein, globulin concentrations and more activity of CK than herded goats. On the other hand, herded goats had higher (P<0.05) plasma glucose (H: 3.39±0.020 vs T: 3.23±0.020 mmol/L), serum albumin (H: 15.30±0.147 vs T: 14.82±0.144 g/L) concentration. It was concluded that serum concentrations of all the metabolites and the activity of CK were sensitive to grazing system. Herding of goats promoted more glucose concentration and preservation of muscle protein and hence superior body weights and BCS than tethered goats. The fourth experiment was done to determine the effects of grazing and housing management systems on the activity of creatine kinase (CK) and cortisol concentration, and chevon quality. Further, the effect of muscle type [Muscularis longissimus thoracis et. Lumborum (LTL) and triceps brachii (TB)] on chevon quality was also investigated. Forty eight castrated Nguni goats aged 6- 7 months were randomly allocated to tethering (n=24) and herding (n=24) treatments. Floor type affected meat (P<0.05) pH24. Tethered goats had higher (P < 0.05) L* and CL percent than herded goats. Muscle type had a significant influence (P < 0.05) on a*, WBSF and pH. It was observed and concluded that T resulted in higher L* and more CL percent whilst SF lowered the pH24 of chevon; at the same time meat from the TB muscle was more tender, despite having a higher pH24 and more CL percent relative to LTH cuts. The fifth experiment was done to determine the effect of grazing and floor type on fatty acid composition of chevon from tethered and herded Nguni goats. Floor type had no effect on fatty acid composition. Oleic, stearic, palmitic and linoleic were the major fatty acids. Chevon from tethered goats had higher (P < 0.05) proportions of long chain polyunsaturated fatty acids (PUFAs): eicosapentaenoic, docosapentaenoic, docosahexaenoic, conjugated linoleic acid (CLA) and more total SFA, total PUFA, total Omega- 6 and total omega 3 fatty acids than herded goats. On the other hand, chevon from herded goats had more (P < 0.05) C18:1c9, C18:2t9, 12 (n-6), C20:3c11, 14, 17 (n-3) and total MUFA than tethered goats. However, there was no difference (P > 0.05) in the PUFA: SFA and n-6/n-3 fatty acid ratios between the herded and tethered goats. It was concluded that tethering promoted higher proportions of beneficial PUFAs which were more in TB than LTH muscle. The overall conclusions from the whole study were that goat manure is an important source of GHG with high CH4 being emitted from earth floors of herded goats. High CO2 and N2O are emitted from SF of herded and tethered goats, respectively. There were no major differences in meat quality between herded and tethered goats. However, herding promoted more live weight gain than tethering. On the other hand, tethering promoted more beneficial fatty acids. Therefore depending on the objective of the enterprise, smallholder farmers can safely tether or herd their goats. Further, there is need to develop technologies to harness CH4 from goat manure.
- Full Text:
Farm to abattoir conditions and their subsequent effects on behavioural and physiological changes and the quality of beef from extensively-reared Nguni and non-descript steers
- Authors: Njisane, Yonela Zifikile
- Date: 2016
- Subjects: Nguni cattle Beef cattle breeds Beef -- Quality -- South Africa , Slaughtering and slaughter-houses -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/3143 , vital:28324
- Description: The main objective of the study was to determine the effect of farm to abattoir environmental conditions and their subsequent effects on behavioural and physiological responses, as well as the quality of meat from Nguni (NG) and non-descript (ND) beef steers reared extensively on natural pastures. The forty 16 – 19 months old steers (20 ND and 20 NG) used in the current study were grouped together, medically treated, allowed three weeks acclimatizing period and were used in this trial over a four-month period. The weather and periodical variations influence on time budgets and body weights of these steers were determined. Furthermore, the effects of on-farm successive handling on behavioural scores and physiological responses of the same steers were determined. Later in the trial, some pre-slaughter effects on response-behaviour, bleed-out times and selected blood physiological responses were determined. Finally, the effect of genotype, muscle type, lairage duration, slaughter order and stress responsiveness on pH24, temperature, colour (L*, a*, b*, C, HA), thawing (TL) and cooking (CL) losses and Warner Bratzler Shear Force (WBSF) of the meat harvested from the same steers were determined. The daily time budgets of steers in natural pastures changed with temperature, humidity, observation week and time of the day. The grazing behaviour was observed throughout the observation days (> 37 percent); though it was reduced (26.9±2.64 percent) on days with higher temperatures and low humidity. Higher proportions of drinking (1.5±1.04 percent) and standing (20.8±4.63 percent) behaviours prolonged in such weather conditions, which were mostly during midday. The avoidance-related behaviour of the steers during handling varies, with the steers showing more avoidance and aggression in other weeks than some. These variations could however be traced back to the events of that particular day/time of handling. Only Weighing Box (WBS) and stepping (SS) scores differed (P<0.05) with genotype; with more calm NG steers (> 40 percent) and not kicking than the ND steers that were more vocal (20–60 percent) and kicking (> 5 percent). In addition, the weekly behavioural responses were reflected (P<0.05) in the measured cortisol, glucose and lactate. However, regardless of the prominent negative behaviour seen over time, the levels of the measured blood constituents continued to drop. Furthermore, steers of different genotypes displayed similar (P>0.05) response to the identical pre-slaughter conditions they were exposed to. However, steers that were Transport Group 1 (TG1) showed more avoidance (63.2 percent) pre-slaughter than those in TG2 (23.9 percent). Furthermore, all the steers that were in slaughter Group 2 (SG2) showed less avoidance behaviour than those in other groups. Vocalization was observed only for ND steers (5 percent), in TG1 and SG2. Some connections between the observed pre-slaughter activities and some behavioural and physiological changes of these steers were established; with TG1 and SG1 steers showing higher cortisol (140±14.50 and 175.9±17.24 nmol/L, respectively) and lactate (12.4±0.83 and 13.5±1.12 mmolL) levels than the other groups. Lastly, the muscle type, genotype, lairage duration, slaughter order and stress responsiveness have an effect on some meat quality characteristics of the two genotypes; with the L. dorsi muscle having highest WBSF (38.0±1.35N) than the Superficial pectoral muscle (Brisket muscle) (30.7±1.35N). Additionally, steers lairaged for a shorter time produced a L. dorsi with higher WBSF (41.6±2.34N) and a Brisket with lower TL (2.7±0.24 percent). It can therefore be concluded that the conditions and activities at the farm, during transportation, lairaging and slaughter at the abattoir have an influence on some behavioural and physiological changes and the quality of beef harvested from the Nguni and non-descript steers that were extensively-reared in natural pastures. However, the relationship patterns between these different conditions are not clear.
- Full Text:
- Authors: Njisane, Yonela Zifikile
- Date: 2016
- Subjects: Nguni cattle Beef cattle breeds Beef -- Quality -- South Africa , Slaughtering and slaughter-houses -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/3143 , vital:28324
- Description: The main objective of the study was to determine the effect of farm to abattoir environmental conditions and their subsequent effects on behavioural and physiological responses, as well as the quality of meat from Nguni (NG) and non-descript (ND) beef steers reared extensively on natural pastures. The forty 16 – 19 months old steers (20 ND and 20 NG) used in the current study were grouped together, medically treated, allowed three weeks acclimatizing period and were used in this trial over a four-month period. The weather and periodical variations influence on time budgets and body weights of these steers were determined. Furthermore, the effects of on-farm successive handling on behavioural scores and physiological responses of the same steers were determined. Later in the trial, some pre-slaughter effects on response-behaviour, bleed-out times and selected blood physiological responses were determined. Finally, the effect of genotype, muscle type, lairage duration, slaughter order and stress responsiveness on pH24, temperature, colour (L*, a*, b*, C, HA), thawing (TL) and cooking (CL) losses and Warner Bratzler Shear Force (WBSF) of the meat harvested from the same steers were determined. The daily time budgets of steers in natural pastures changed with temperature, humidity, observation week and time of the day. The grazing behaviour was observed throughout the observation days (> 37 percent); though it was reduced (26.9±2.64 percent) on days with higher temperatures and low humidity. Higher proportions of drinking (1.5±1.04 percent) and standing (20.8±4.63 percent) behaviours prolonged in such weather conditions, which were mostly during midday. The avoidance-related behaviour of the steers during handling varies, with the steers showing more avoidance and aggression in other weeks than some. These variations could however be traced back to the events of that particular day/time of handling. Only Weighing Box (WBS) and stepping (SS) scores differed (P<0.05) with genotype; with more calm NG steers (> 40 percent) and not kicking than the ND steers that were more vocal (20–60 percent) and kicking (> 5 percent). In addition, the weekly behavioural responses were reflected (P<0.05) in the measured cortisol, glucose and lactate. However, regardless of the prominent negative behaviour seen over time, the levels of the measured blood constituents continued to drop. Furthermore, steers of different genotypes displayed similar (P>0.05) response to the identical pre-slaughter conditions they were exposed to. However, steers that were Transport Group 1 (TG1) showed more avoidance (63.2 percent) pre-slaughter than those in TG2 (23.9 percent). Furthermore, all the steers that were in slaughter Group 2 (SG2) showed less avoidance behaviour than those in other groups. Vocalization was observed only for ND steers (5 percent), in TG1 and SG2. Some connections between the observed pre-slaughter activities and some behavioural and physiological changes of these steers were established; with TG1 and SG1 steers showing higher cortisol (140±14.50 and 175.9±17.24 nmol/L, respectively) and lactate (12.4±0.83 and 13.5±1.12 mmolL) levels than the other groups. Lastly, the muscle type, genotype, lairage duration, slaughter order and stress responsiveness have an effect on some meat quality characteristics of the two genotypes; with the L. dorsi muscle having highest WBSF (38.0±1.35N) than the Superficial pectoral muscle (Brisket muscle) (30.7±1.35N). Additionally, steers lairaged for a shorter time produced a L. dorsi with higher WBSF (41.6±2.34N) and a Brisket with lower TL (2.7±0.24 percent). It can therefore be concluded that the conditions and activities at the farm, during transportation, lairaging and slaughter at the abattoir have an influence on some behavioural and physiological changes and the quality of beef harvested from the Nguni and non-descript steers that were extensively-reared in natural pastures. However, the relationship patterns between these different conditions are not clear.
- Full Text:
Management practices, milk quality, haemato-chemical biomarkers of free ranging pregnant goats from three genotypes and linear body measurements of their respective kids
- Idamokoro, Emrobowansan Monday
- Authors: Idamokoro, Emrobowansan Monday
- Date: 2016
- Subjects: Milk--Quality Biochemical markers Goat milk
- Language: English
- Type: Thesis , Doctoral , Animal Science
- Identifier: http://hdl.handle.net/10353/11548 , vital:39082
- Description: The broad objective of this study was to assess farmers’ perceptions on the welfare and management practices of pregnant goats and to determine the effect of genotypes and physiological status on doe’s performance (blood metabolites and milk quality) and their respective kid’s linear body measurements of goats reared in an extensive system of production. A survey was conducted among 153 goat farmers to assess their perception on goat mortality and management practices during and after gestation period. The results from the survey showed that 98.7percent of the farmers depended on pastures to feed their pregnant and lactating does. Majority of the farmers (59.9percent) did not vaccinate their dams against diseases before using them for breeding purposes. An aggregate of 77.8percent respondents allowed their does to mate freely on the veld. Most of the respondents (75.2percent) kept their pregnant goats together with other flocks in mud floor pen (kraals) fenced with tree branches. Farmers indicated that, poor diet (32percent), disease (24 percent) and predators (15percent) were some factors that cause mortality in pregnant does. About 66.7percent respondents perceived that, quality diet is a factor that can boost the reproductive performance of pregnant goats. The haemato-biochemical parameters of Nguni, Boer and Non-descript goats at late and early lactation revealed that, Nguni goat had higher (P ˂ 0.05) values of red cell counts (13.37 x1011/L), haemoglobin (9.07 g/dL) and creatine kinase (269.54 U/L) compared to Boer (9.96 x 1011/L, 7.94 g/ dL and 132.16 U/L) and Non-descript goats (12.98 x 1011 /L, 7.85 g/ dL and 143.50 U/L), respectively. The Nguni goats also had higher (P ˂ 0.05) mean values of glucose (3.38 mmol/L), sodium (141.66 mmol/L) and urea content (5.51 mmol/L) compared to Boer (2.96 mmol/L, 135.70 mmol/L and 4.45 mmol/L) and Non-descript goats (2.50 mmol/L, 141.31 mmol/L and 3.90 mmol/L), respectively. The results of blood metabolites also revealed that, there was significant difference (P < 0.05) in the physiological status of goats. The late stage of pregnancy had higher mean values of red cell counts (14.44 x 1011 /L), haemoglobin (8.57 g/dL), haematocrit (0.67 L/L), glucose (3.12 mmol/L), sodium (141.74 mmol/L) and calcium content (2.37 mmol/L) compared to the early stage of lactation (9.77 x 1011/ L, 8.00 g /dL, 0.55 L/L, 2.77 mmol/L, 137.37 mmol/L and 2.23 mmol/L), respectively. Furthermore, it was revealed that, Nguni goats produced (1.2±0.09, 1.3±0.11 and 1.2±0.07 litres per day) more milk (P ˂ 0.05) at early, mid and late stages of lactation than Boer (0.6±0.10, 1.0±0.17 and 0.6±0.09 litres per day) and Non-descript (0.3±0.10, 0.3±0.12 and 0.3±0.09 litres per day) goats. There was significant difference (P ˂ 0.05) of genotypes on milk fat, milk magnesium and sodium contents among Nguni, Boer and Non-descript goats. Lactation stages had a significant effect (P ˂ 0.05) on some milk compositions (fat, protein, lactose and solid non-fat) and mineral profiles (Ca, Mg, Na, K, and Fe) of Nguni goats. Lactation stages had a significant effect (P ˂ 0.05) on fat, protein, lactose and solid non-fat content and mineral profiles (Ca, Mg, Na, K, and Fe) of Nguni goats. Milk protein content of Nguni goat was positively correlated to milk fat but, not in Boer and Non-descript goats. Milk quality parameters from the three goat genotypes possessed relatively moderate milk compositions and mineral profiles which is comparable to some exotic goat breeds. Nguni kids had higher mean weights (7.36 kg, 11.85 kg and 13.72 kg) than the Boer kids (5.20 kg, 7.18 kg and 10.20 kg) and the Non-descript goat kids (5.23 kg, 6.19 kg and 8.01 kg) at weeks 4, 6 and 8 after parturition, respectively. In terms of height at withers, the Nguni kids had higher mean values in heights (41.92 cm, 44.71 cm, 49.38 cm and 55.75 cm) than the Boer kids (35.67 cm, 37.14 cm, 42.40 and 44.20 cm) and the Non-descript kids (36.38 cm, 40.20 cm, 41.14 cm and 43.50 cm) at week 2, 4, 6 and 8 after parturition, respectively. Conversely, there was a positive correlation (P ˂ 0.05) between body lengths and live weights of Nguni goats and not in Boer and Non-descript goats. It was concluded from this study that, the indigenous Nguni, Boer and Non-descript pregnant goats were managed in poor conditions by communal farmers and the perceived causes of mortality of pregnant goats among others include poor feed, diseases and predators. In addition, the Nguni goats had higher mean values in some haematological parameters (red cell counts and haemoglobin) and serum biochemical profiles (glucose, sodium, urea and creatine kinase) than Boer and Non-descript goats during the periods of investigation. Nguni goats also produced more milk at the early and late stages of lactation compared to the Boer and Non-descript goats. The Non-descript goats had a higher mean value of milk fat compared to Nguni and Boer goats. Likewise, the Boer goats were observed to have higher mean value of milk magnesium and sodium content compared to Nguni and Non-descript goats. In terms of body weights and linear body measurments, the Nguni goat kids were superior compared to Boer and Non-descript goats.
- Full Text: false
- Authors: Idamokoro, Emrobowansan Monday
- Date: 2016
- Subjects: Milk--Quality Biochemical markers Goat milk
- Language: English
- Type: Thesis , Doctoral , Animal Science
- Identifier: http://hdl.handle.net/10353/11548 , vital:39082
- Description: The broad objective of this study was to assess farmers’ perceptions on the welfare and management practices of pregnant goats and to determine the effect of genotypes and physiological status on doe’s performance (blood metabolites and milk quality) and their respective kid’s linear body measurements of goats reared in an extensive system of production. A survey was conducted among 153 goat farmers to assess their perception on goat mortality and management practices during and after gestation period. The results from the survey showed that 98.7percent of the farmers depended on pastures to feed their pregnant and lactating does. Majority of the farmers (59.9percent) did not vaccinate their dams against diseases before using them for breeding purposes. An aggregate of 77.8percent respondents allowed their does to mate freely on the veld. Most of the respondents (75.2percent) kept their pregnant goats together with other flocks in mud floor pen (kraals) fenced with tree branches. Farmers indicated that, poor diet (32percent), disease (24 percent) and predators (15percent) were some factors that cause mortality in pregnant does. About 66.7percent respondents perceived that, quality diet is a factor that can boost the reproductive performance of pregnant goats. The haemato-biochemical parameters of Nguni, Boer and Non-descript goats at late and early lactation revealed that, Nguni goat had higher (P ˂ 0.05) values of red cell counts (13.37 x1011/L), haemoglobin (9.07 g/dL) and creatine kinase (269.54 U/L) compared to Boer (9.96 x 1011/L, 7.94 g/ dL and 132.16 U/L) and Non-descript goats (12.98 x 1011 /L, 7.85 g/ dL and 143.50 U/L), respectively. The Nguni goats also had higher (P ˂ 0.05) mean values of glucose (3.38 mmol/L), sodium (141.66 mmol/L) and urea content (5.51 mmol/L) compared to Boer (2.96 mmol/L, 135.70 mmol/L and 4.45 mmol/L) and Non-descript goats (2.50 mmol/L, 141.31 mmol/L and 3.90 mmol/L), respectively. The results of blood metabolites also revealed that, there was significant difference (P < 0.05) in the physiological status of goats. The late stage of pregnancy had higher mean values of red cell counts (14.44 x 1011 /L), haemoglobin (8.57 g/dL), haematocrit (0.67 L/L), glucose (3.12 mmol/L), sodium (141.74 mmol/L) and calcium content (2.37 mmol/L) compared to the early stage of lactation (9.77 x 1011/ L, 8.00 g /dL, 0.55 L/L, 2.77 mmol/L, 137.37 mmol/L and 2.23 mmol/L), respectively. Furthermore, it was revealed that, Nguni goats produced (1.2±0.09, 1.3±0.11 and 1.2±0.07 litres per day) more milk (P ˂ 0.05) at early, mid and late stages of lactation than Boer (0.6±0.10, 1.0±0.17 and 0.6±0.09 litres per day) and Non-descript (0.3±0.10, 0.3±0.12 and 0.3±0.09 litres per day) goats. There was significant difference (P ˂ 0.05) of genotypes on milk fat, milk magnesium and sodium contents among Nguni, Boer and Non-descript goats. Lactation stages had a significant effect (P ˂ 0.05) on some milk compositions (fat, protein, lactose and solid non-fat) and mineral profiles (Ca, Mg, Na, K, and Fe) of Nguni goats. Lactation stages had a significant effect (P ˂ 0.05) on fat, protein, lactose and solid non-fat content and mineral profiles (Ca, Mg, Na, K, and Fe) of Nguni goats. Milk protein content of Nguni goat was positively correlated to milk fat but, not in Boer and Non-descript goats. Milk quality parameters from the three goat genotypes possessed relatively moderate milk compositions and mineral profiles which is comparable to some exotic goat breeds. Nguni kids had higher mean weights (7.36 kg, 11.85 kg and 13.72 kg) than the Boer kids (5.20 kg, 7.18 kg and 10.20 kg) and the Non-descript goat kids (5.23 kg, 6.19 kg and 8.01 kg) at weeks 4, 6 and 8 after parturition, respectively. In terms of height at withers, the Nguni kids had higher mean values in heights (41.92 cm, 44.71 cm, 49.38 cm and 55.75 cm) than the Boer kids (35.67 cm, 37.14 cm, 42.40 and 44.20 cm) and the Non-descript kids (36.38 cm, 40.20 cm, 41.14 cm and 43.50 cm) at week 2, 4, 6 and 8 after parturition, respectively. Conversely, there was a positive correlation (P ˂ 0.05) between body lengths and live weights of Nguni goats and not in Boer and Non-descript goats. It was concluded from this study that, the indigenous Nguni, Boer and Non-descript pregnant goats were managed in poor conditions by communal farmers and the perceived causes of mortality of pregnant goats among others include poor feed, diseases and predators. In addition, the Nguni goats had higher mean values in some haematological parameters (red cell counts and haemoglobin) and serum biochemical profiles (glucose, sodium, urea and creatine kinase) than Boer and Non-descript goats during the periods of investigation. Nguni goats also produced more milk at the early and late stages of lactation compared to the Boer and Non-descript goats. The Non-descript goats had a higher mean value of milk fat compared to Nguni and Boer goats. Likewise, the Boer goats were observed to have higher mean value of milk magnesium and sodium content compared to Nguni and Non-descript goats. In terms of body weights and linear body measurments, the Nguni goat kids were superior compared to Boer and Non-descript goats.
- Full Text: false
Moringa oleifera leaf powder as a functional antioxidant additive in pork droewors
- Authors: Mukumbo, Felicitas Esnart
- Date: 2016
- Subjects: Antioxidants , Moringa oleifera , Pork -- Quality
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15354 , vital:40400
- Description: The study investigated the effect of Moringa oleifera leaf powder (MLP) on physico-chemical characteristics, antioxidant activity, antioxidant compound content and lipid oxidation in pork droëwors. Firstly, the physico-chemical properties (proximate composition, salt content, water activity (aw), pH) of commercially produced droëwors from different types of meat (beef, game, ostrich) were determined. In the second experiment beef and pork droëwors with similar fat content were produced. Physico-chemical properties and lipid oxidation (thiobarbituric reactive substances (TBARS)) during processing and 26 days of storage at 25 °C and 50percent relative humidity (RH) were measured. In the third experiment, antioxidant compounds (Total Phenolic Compounds (TPC), α-tocopherol, β-carotene) in MLP were quantified. Thereafter, 4 treatments of pork droëwors were produced, with MLP included at 0, 0.5, 1 and 2 g/ 100 g. Physico-chemical properties and TBARS were measured at intervals during drying (0, 1.5, 5.75, 27.25, 72 h) and after 7 days of storage under ambient conditions. Antioxidant activity (ferric reducing antioxidant power (FRAP)), TBARS, α- and γ-tocopherol, and β-carotene contents were measured. In the fourth experiment, three batches of droëwors were produced (C: no antioxidant, M0.75: 0.75 g/ 100 g MLP, VE: 15 mg/ kg α-tocopherol oil) and stored at 25 °C and 50percent relative humidity for 112 days. Drying kinetics and α-tocopherol contents of pork droëwors after drying were measured and the physico-chemical properties and TBARS were followed during storage. Results showed no differences (P > 0.05) in the physico-chemical characteristics of beef, game meat and ostrich droëwors; containing on average 25.8 ± 1.25 g/100 g moisture, 42.0 ± 0.10 g/100 g protein, 32.0 ± 1.68 g/100 g fat, 6.2 ± 0.13 g/100 g ash and 4.2 ± 0.10 g/100 g salt; with aw and pH of 0.79 ± 0.015 and 5.3 ± 0.05, respectively. During processing and storage, TBARS were higher (P < 0.05) in pork droëwors (maximum 3.83 mg MDA/kg DM) than in beef (maximum 0.99 mg MDA/kg DM). Moringa oleifera leaf powder contained high levels of TPC (7.5 ± 0.2 mg gallic acid eq/g) and substantial levels of α-tocopherol (76.7 ± 1.9 mg/100 g) and β-carotene (23.2 ± 2.8 mg/100 g). The FRAP, α-tocopherol and β-carotene content of pork droëwors increased (P < 0.05) proportionally with increasing levels of MLP inclusion. Lipid oxidation occurred more rapidly (P < 0.05) when MLP was not added and was similar (P > 0.05) for all MLP treatments. There was no significant effect of the inclusion of 0.75 g/100 g MLP on the drying curves and physico-chemical characteristics of the droëwors. The α-tocopherol content was higher (P < 0.05) and TBARS during storage were lower (P > 0.05) with MLP addition. The results of the current study give an overview of the composition of commercial droëwors and showed higher susceptibility to lipid oxidation in pork droëwors. Moringa oleifera leaf powder exhibited antioxidant activity in pork droëwors, inhibited lipid oxidation and increased the content of α-tocopherol in the product. It can be concluded that MLP could be used as a functional antioxidant additive in pork droëwors.
- Full Text:
- Authors: Mukumbo, Felicitas Esnart
- Date: 2016
- Subjects: Antioxidants , Moringa oleifera , Pork -- Quality
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15354 , vital:40400
- Description: The study investigated the effect of Moringa oleifera leaf powder (MLP) on physico-chemical characteristics, antioxidant activity, antioxidant compound content and lipid oxidation in pork droëwors. Firstly, the physico-chemical properties (proximate composition, salt content, water activity (aw), pH) of commercially produced droëwors from different types of meat (beef, game, ostrich) were determined. In the second experiment beef and pork droëwors with similar fat content were produced. Physico-chemical properties and lipid oxidation (thiobarbituric reactive substances (TBARS)) during processing and 26 days of storage at 25 °C and 50percent relative humidity (RH) were measured. In the third experiment, antioxidant compounds (Total Phenolic Compounds (TPC), α-tocopherol, β-carotene) in MLP were quantified. Thereafter, 4 treatments of pork droëwors were produced, with MLP included at 0, 0.5, 1 and 2 g/ 100 g. Physico-chemical properties and TBARS were measured at intervals during drying (0, 1.5, 5.75, 27.25, 72 h) and after 7 days of storage under ambient conditions. Antioxidant activity (ferric reducing antioxidant power (FRAP)), TBARS, α- and γ-tocopherol, and β-carotene contents were measured. In the fourth experiment, three batches of droëwors were produced (C: no antioxidant, M0.75: 0.75 g/ 100 g MLP, VE: 15 mg/ kg α-tocopherol oil) and stored at 25 °C and 50percent relative humidity for 112 days. Drying kinetics and α-tocopherol contents of pork droëwors after drying were measured and the physico-chemical properties and TBARS were followed during storage. Results showed no differences (P > 0.05) in the physico-chemical characteristics of beef, game meat and ostrich droëwors; containing on average 25.8 ± 1.25 g/100 g moisture, 42.0 ± 0.10 g/100 g protein, 32.0 ± 1.68 g/100 g fat, 6.2 ± 0.13 g/100 g ash and 4.2 ± 0.10 g/100 g salt; with aw and pH of 0.79 ± 0.015 and 5.3 ± 0.05, respectively. During processing and storage, TBARS were higher (P < 0.05) in pork droëwors (maximum 3.83 mg MDA/kg DM) than in beef (maximum 0.99 mg MDA/kg DM). Moringa oleifera leaf powder contained high levels of TPC (7.5 ± 0.2 mg gallic acid eq/g) and substantial levels of α-tocopherol (76.7 ± 1.9 mg/100 g) and β-carotene (23.2 ± 2.8 mg/100 g). The FRAP, α-tocopherol and β-carotene content of pork droëwors increased (P < 0.05) proportionally with increasing levels of MLP inclusion. Lipid oxidation occurred more rapidly (P < 0.05) when MLP was not added and was similar (P > 0.05) for all MLP treatments. There was no significant effect of the inclusion of 0.75 g/100 g MLP on the drying curves and physico-chemical characteristics of the droëwors. The α-tocopherol content was higher (P < 0.05) and TBARS during storage were lower (P > 0.05) with MLP addition. The results of the current study give an overview of the composition of commercial droëwors and showed higher susceptibility to lipid oxidation in pork droëwors. Moringa oleifera leaf powder exhibited antioxidant activity in pork droëwors, inhibited lipid oxidation and increased the content of α-tocopherol in the product. It can be concluded that MLP could be used as a functional antioxidant additive in pork droëwors.
- Full Text:
Effects of natural antioxidants and thermal treatment on quality of meat from Bonsmara and non-descripts cattle
- Authors: Falowo, Andrew Bamidele
- Date: 2015
- Subjects: Meat -- Preservation Antioxidants Meat -- Microbiology
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/2589 , vital:27906
- Description: The broad objective of this study was to determine the effects of natural antioxidants and thermal treatment on quality of meat from Bonsmara and non-descript cattle. A survey was conducted among 222 consumers in Alice (Fort Hare University community), Eastern Cape Province to determine the level of their awareness on application of antioxidants as preservatives in meat and meat products during storage. Representative samples of Muscularis longissimuss thoracis et lumborum and liver were collected from each carcass of Bonsmara (n=40) and non-descript (n=40) cattle reared on natural pasture to determine the effect of natural antioxidants and thermal treatment on their quality. The results from the survey revealed that 51.35 percent of the respondents had not heard about the use of antioxidant as preservatives in meat products. However, among the remaining respondents (48.65 percent) that were aware of antioxidant and its use as preservative, about 19 percent knew of natural antioxidants, 35 percent synthetic antioxidants while 46 percent had knowledge of both. The results further revealed that the majority of the respondents (82 percent) that had knowledge of natural antioxidants were concerned about the use of synthetic antioxidants in meat and meat products due to their health consequences. The in vitro antioxidant and antibacterial analyses of Bidens pilosa and Moringa oleifera leaf extracts revealed that they contain rich bioactive compounds. Furthermore, the addition of leaf extracts from Moringa oleifera (ML, 0.05 and 0.1 percent w/w) and Biden pilosa (BP, 0.05 and 0.1 percent w/w) to ground raw beef as a natural antioxidant were found to improve the physicochemical, oxidative stability and microbiological qualities of meat compared to the control (meat without extract) and BHT treatment (0.02 percent w/w) during 6 days storage at 40 C. Cattle breed did not have much effect on colour parameters. However, the overall pH of ground beef treated with extracts showed lower values than control and BHT treated beef. Also, ground beef samples containing extracts exhibited (P < 0.05) better colour stability, especially higher redness (a* values), than the control. The formation of TBARS in beef samples treated with extracts was significantly (P < 0.05) lower than the control and BHT treatment. The antibacterial assay of the extracts revealed an appreciable broad spectrum activity against the tested bacteria and microbial counts in ground beef samples compared to control and BHT group. Ground beef treated with plant extracts exhibited lower microbial and lactic acid bacterial counts (P < 0.05) at day 0 and 3 than control samples. Moreover, it was observed that application of sous vides thermal method did not significantly affect the fatty acids and mineral loss in beef and liver across the treatments. However, the total concentration of MUFA was lower in raw liver (20.11±2.38 - 21.08±1.23 percent) than in beef (40.22±1.90 - 42.53±1.29 percent), while total PUFA content were higher in liver (30.73±2.60 - 31.11±1.19 percent) than in beef samples (10.13±3.36 - 11.02±2.74 percent) (p < 0.05). The results also revealed that liver samples from Bonsmara and non-descript cattle had a higher percentage of intramuscular fat content of 4.67 ± 0.53 percent and 4.44 ± 0.53 percent respectively, and fat free dry matter of 27.51 ± 1.05 percent and 25.73 ± 1.05 percent, respectively, than the beef samples (p < 0.05). The concentrations of Mg (52.80±0.22 - 53.70±0.02mg/100g) and Zn (8.90±0.15 - 19.60±0.15mg/100g) were higher in beef than liver samples. The level of Ca (17.00±0.17 - 17.50 ± 0.17mg/100g) in liver was higher than that of beef samples. It was concluded that most consumers preferred the use of natural antioxidants in meat products than synthetic antioxidants due to their health risk. The effectiveness of M. oleifera and B. pilosa leaf extracts on meat quality also revealed that these plants are promising candidates as natural preservatives and their application should be considered in the meat industry. Lastly, findings from this study showed that application of the sous vide technique could protect meat products from nutritional loss during thermal treatment.
- Full Text:
- Authors: Falowo, Andrew Bamidele
- Date: 2015
- Subjects: Meat -- Preservation Antioxidants Meat -- Microbiology
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/2589 , vital:27906
- Description: The broad objective of this study was to determine the effects of natural antioxidants and thermal treatment on quality of meat from Bonsmara and non-descript cattle. A survey was conducted among 222 consumers in Alice (Fort Hare University community), Eastern Cape Province to determine the level of their awareness on application of antioxidants as preservatives in meat and meat products during storage. Representative samples of Muscularis longissimuss thoracis et lumborum and liver were collected from each carcass of Bonsmara (n=40) and non-descript (n=40) cattle reared on natural pasture to determine the effect of natural antioxidants and thermal treatment on their quality. The results from the survey revealed that 51.35 percent of the respondents had not heard about the use of antioxidant as preservatives in meat products. However, among the remaining respondents (48.65 percent) that were aware of antioxidant and its use as preservative, about 19 percent knew of natural antioxidants, 35 percent synthetic antioxidants while 46 percent had knowledge of both. The results further revealed that the majority of the respondents (82 percent) that had knowledge of natural antioxidants were concerned about the use of synthetic antioxidants in meat and meat products due to their health consequences. The in vitro antioxidant and antibacterial analyses of Bidens pilosa and Moringa oleifera leaf extracts revealed that they contain rich bioactive compounds. Furthermore, the addition of leaf extracts from Moringa oleifera (ML, 0.05 and 0.1 percent w/w) and Biden pilosa (BP, 0.05 and 0.1 percent w/w) to ground raw beef as a natural antioxidant were found to improve the physicochemical, oxidative stability and microbiological qualities of meat compared to the control (meat without extract) and BHT treatment (0.02 percent w/w) during 6 days storage at 40 C. Cattle breed did not have much effect on colour parameters. However, the overall pH of ground beef treated with extracts showed lower values than control and BHT treated beef. Also, ground beef samples containing extracts exhibited (P < 0.05) better colour stability, especially higher redness (a* values), than the control. The formation of TBARS in beef samples treated with extracts was significantly (P < 0.05) lower than the control and BHT treatment. The antibacterial assay of the extracts revealed an appreciable broad spectrum activity against the tested bacteria and microbial counts in ground beef samples compared to control and BHT group. Ground beef treated with plant extracts exhibited lower microbial and lactic acid bacterial counts (P < 0.05) at day 0 and 3 than control samples. Moreover, it was observed that application of sous vides thermal method did not significantly affect the fatty acids and mineral loss in beef and liver across the treatments. However, the total concentration of MUFA was lower in raw liver (20.11±2.38 - 21.08±1.23 percent) than in beef (40.22±1.90 - 42.53±1.29 percent), while total PUFA content were higher in liver (30.73±2.60 - 31.11±1.19 percent) than in beef samples (10.13±3.36 - 11.02±2.74 percent) (p < 0.05). The results also revealed that liver samples from Bonsmara and non-descript cattle had a higher percentage of intramuscular fat content of 4.67 ± 0.53 percent and 4.44 ± 0.53 percent respectively, and fat free dry matter of 27.51 ± 1.05 percent and 25.73 ± 1.05 percent, respectively, than the beef samples (p < 0.05). The concentrations of Mg (52.80±0.22 - 53.70±0.02mg/100g) and Zn (8.90±0.15 - 19.60±0.15mg/100g) were higher in beef than liver samples. The level of Ca (17.00±0.17 - 17.50 ± 0.17mg/100g) in liver was higher than that of beef samples. It was concluded that most consumers preferred the use of natural antioxidants in meat products than synthetic antioxidants due to their health risk. The effectiveness of M. oleifera and B. pilosa leaf extracts on meat quality also revealed that these plants are promising candidates as natural preservatives and their application should be considered in the meat industry. Lastly, findings from this study showed that application of the sous vide technique could protect meat products from nutritional loss during thermal treatment.
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