Effect of dietary Mucuna pruriens seed meal on the serum lipid profile and bone quality traits of broiler chickens
- Authors: Hempe, Chumani
- Date: 2019
- Subjects: Legumes Lipoproteins
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/17213 , vital:40866
- Description: This study aimed at evaluating the effects of heated Mucuna pruriens seed meal on the blood serum lipid profile and bone quality parameters of broiler chickens. A total of 120 day-old unsexed Cobb 500 broiler chicks were randomly allocated for the 4 treatment diets (T1, T2, T3 and T4) containing 0, 10, 15, and 20% heated Mucuna pruriens seed meal. The birds were reared on wood shaving floor pens for 35 days. Birds were humanely slaughtered by severing the jugular vein using a sharp knife. Blood was collected into a tube, centrifuge and analyzed for a lipid profile analysis (total cholesterol (TC), high density lipoproteins (HDL), low density lipoproteins (LDL), triglycerides (TCD) as well as aspartate transaminase (AST) and alanine transaminase (ALT)) by enzymatic diagnostic kits (Diasys diagnostic kits). Both drumsticks severed using a sharp knife. After boiling in the water at 100°C for 10 mins the tibia bones were taken, air-dried for 96 hrs at room temperature and measured for weights. Bone length, strength, moisture and ash content as well as morphology were measured. The blood lipid profile of birds fed T1 was high (P < 0.05) for all the parameters measured, while T3 had the lowest (P < 0.05) profile. T2 and T4 had the same profile. ALT was found to be highest (P < 0.05) for T4 (5.27 ± 0.207/L) and lowest (P < 0.05) for T2 (4.67 ± 0.333/L) while AST was highest (P < 0.05) for T2 (320.13 ± 28.851/L) and lowest (P < 0.05) for T3 (208.47 ± 10.059/L). Treatment diet 3 (T3) was observed decreased bone quality among all diets; with the lowest (P < 0.05) bone strength (188.55 ± 12.039N), bone length (8.59 ± 0.131cm) and morphology (1.69 ± 0.058). Mucuna pruriens seed meal inclusion in broiler diets reduces blood serum lipids and 20% inclusion levels have no adverse effects on the bone quality attributes
- Full Text:
- Authors: Hempe, Chumani
- Date: 2019
- Subjects: Legumes Lipoproteins
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/17213 , vital:40866
- Description: This study aimed at evaluating the effects of heated Mucuna pruriens seed meal on the blood serum lipid profile and bone quality parameters of broiler chickens. A total of 120 day-old unsexed Cobb 500 broiler chicks were randomly allocated for the 4 treatment diets (T1, T2, T3 and T4) containing 0, 10, 15, and 20% heated Mucuna pruriens seed meal. The birds were reared on wood shaving floor pens for 35 days. Birds were humanely slaughtered by severing the jugular vein using a sharp knife. Blood was collected into a tube, centrifuge and analyzed for a lipid profile analysis (total cholesterol (TC), high density lipoproteins (HDL), low density lipoproteins (LDL), triglycerides (TCD) as well as aspartate transaminase (AST) and alanine transaminase (ALT)) by enzymatic diagnostic kits (Diasys diagnostic kits). Both drumsticks severed using a sharp knife. After boiling in the water at 100°C for 10 mins the tibia bones were taken, air-dried for 96 hrs at room temperature and measured for weights. Bone length, strength, moisture and ash content as well as morphology were measured. The blood lipid profile of birds fed T1 was high (P < 0.05) for all the parameters measured, while T3 had the lowest (P < 0.05) profile. T2 and T4 had the same profile. ALT was found to be highest (P < 0.05) for T4 (5.27 ± 0.207/L) and lowest (P < 0.05) for T2 (4.67 ± 0.333/L) while AST was highest (P < 0.05) for T2 (320.13 ± 28.851/L) and lowest (P < 0.05) for T3 (208.47 ± 10.059/L). Treatment diet 3 (T3) was observed decreased bone quality among all diets; with the lowest (P < 0.05) bone strength (188.55 ± 12.039N), bone length (8.59 ± 0.131cm) and morphology (1.69 ± 0.058). Mucuna pruriens seed meal inclusion in broiler diets reduces blood serum lipids and 20% inclusion levels have no adverse effects on the bone quality attributes
- Full Text:
Muscle nanostructure and physicochemical characteristics of South African A and AB mutton classes
- Authors: Mdikili, Zizipho
- Date: 2019
- Subjects: Meat -- Quality -- South Africa
- Language: English
- Type: Thesis , Masters , (MSc) (Animal Science)
- Identifier: http://hdl.handle.net/10353/12005 , vital:39126
- Description: Significant variations exist in quality of red meat due to the effect of various intrinsic and extrinsic factors. Research has been conducted in early 1990s to prove that carcasses from A and AB classes differ in meat quality due to age variation. This led to a conclusion that the two should be separated in the South African Red meat Classification System (SARCS). However, an interesting debate arose from a carcass classification workshop that A and AB meat classes have the same quality and thus must be integrated into one class in the carcass classification system. In addition, as much as it can be debated that these classes have the same quality, it is also possible that slight differences exist between the two since they are from different age groups. The current study was therefore developed and two trials were conducted to evaluate the impact of age differences on physicochemical attributes and muscle nanostructure of A and AB classes in sheep. In the first trial a total of ninety (n=90) Dorper sheep of the same sex but different age groups slaughtered at a high throughput abattoir in the Eastern Cape province were used to evaluate meat ultimate pH (pH24), colour (L* , a* , b* , H* , C* ), thawing loss (TL%), cooking loss (CL%) and tenderness (Warner Bratzler Shear Force - WBSF) of A and AB classes, whereas, on the second trial forty (n=40) Dorper sheep were used to evaluate muscle nanostructure and its relationship with tenderness. Meat samples were harvested from the Muscularis longissimuss thoracis et lumborum (LTL) for v meat quality and nanostructure measurements. The results showed significant variations (P<0.05) between the two classes for lean a* , H* and CL%. Significant differences (P<0.01) were observed in pH24, TL% and WBSF between A and AB classes. However, there were no significant differences (P>0.05) observed in meat L*, b* and C * . Ultimate pH was negatively correlated with thawing loss and some colorimetric attributes of lamb such as lightness, yellowness and hue angle. Moreover, tenderness was positively correlated with cooking and thawing losses. Significant differences were not (P>0.05) observed in sarcomere length, myofibrilar diameter and shear force between A and AB classes. Both sarcomere length and myofibrilar diameter were not correlated (P>0.05) with meat tenderness. These results suggest that A and AB classes are the same in nanostructure and that muscle nanostructure of these two classes is not related to meat tenderness. It was concluded that meat from sheep carcasses falling under the A and AB classes in the South African classification system vary greatly in physicochemical quality. Moreover, sheep carcasses from A and AB classes have the same sarcomere lengths and hence, they do not differ in meat tenderness (WBSF). However, when these classes were observed under a microscope, slight differences were noted in sarcomere lengths and myofibrilar diameters, which led to a conclusion that the two should remain as separated classes because their combination would result in the expansion of the non-uniformity of red meat tenderness. Therefore, A and AB classes should not be combined in the South African classification system. Further research is, however, recommended to evaluate the influence of other factors that were not examined in the current study.
- Full Text:
- Authors: Mdikili, Zizipho
- Date: 2019
- Subjects: Meat -- Quality -- South Africa
- Language: English
- Type: Thesis , Masters , (MSc) (Animal Science)
- Identifier: http://hdl.handle.net/10353/12005 , vital:39126
- Description: Significant variations exist in quality of red meat due to the effect of various intrinsic and extrinsic factors. Research has been conducted in early 1990s to prove that carcasses from A and AB classes differ in meat quality due to age variation. This led to a conclusion that the two should be separated in the South African Red meat Classification System (SARCS). However, an interesting debate arose from a carcass classification workshop that A and AB meat classes have the same quality and thus must be integrated into one class in the carcass classification system. In addition, as much as it can be debated that these classes have the same quality, it is also possible that slight differences exist between the two since they are from different age groups. The current study was therefore developed and two trials were conducted to evaluate the impact of age differences on physicochemical attributes and muscle nanostructure of A and AB classes in sheep. In the first trial a total of ninety (n=90) Dorper sheep of the same sex but different age groups slaughtered at a high throughput abattoir in the Eastern Cape province were used to evaluate meat ultimate pH (pH24), colour (L* , a* , b* , H* , C* ), thawing loss (TL%), cooking loss (CL%) and tenderness (Warner Bratzler Shear Force - WBSF) of A and AB classes, whereas, on the second trial forty (n=40) Dorper sheep were used to evaluate muscle nanostructure and its relationship with tenderness. Meat samples were harvested from the Muscularis longissimuss thoracis et lumborum (LTL) for v meat quality and nanostructure measurements. The results showed significant variations (P<0.05) between the two classes for lean a* , H* and CL%. Significant differences (P<0.01) were observed in pH24, TL% and WBSF between A and AB classes. However, there were no significant differences (P>0.05) observed in meat L*, b* and C * . Ultimate pH was negatively correlated with thawing loss and some colorimetric attributes of lamb such as lightness, yellowness and hue angle. Moreover, tenderness was positively correlated with cooking and thawing losses. Significant differences were not (P>0.05) observed in sarcomere length, myofibrilar diameter and shear force between A and AB classes. Both sarcomere length and myofibrilar diameter were not correlated (P>0.05) with meat tenderness. These results suggest that A and AB classes are the same in nanostructure and that muscle nanostructure of these two classes is not related to meat tenderness. It was concluded that meat from sheep carcasses falling under the A and AB classes in the South African classification system vary greatly in physicochemical quality. Moreover, sheep carcasses from A and AB classes have the same sarcomere lengths and hence, they do not differ in meat tenderness (WBSF). However, when these classes were observed under a microscope, slight differences were noted in sarcomere lengths and myofibrilar diameters, which led to a conclusion that the two should remain as separated classes because their combination would result in the expansion of the non-uniformity of red meat tenderness. Therefore, A and AB classes should not be combined in the South African classification system. Further research is, however, recommended to evaluate the influence of other factors that were not examined in the current study.
- Full Text:
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:
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