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:
- Date Issued: 2016
- 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:
- Date Issued: 2016
Characterisation of the production and consumption of milk in the communal livestock production sector of the Eastern Cape Province, South Africa
- Authors: Kumbirai, Kaguru Tinashe
- Date: 2016
- Subjects: Milk consumption -- South Africa -- Eastern Cape Dairy farming -- Economic aspects -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/3066 , vital:28251
- Description: The study was conducted in Eastern Cape Province, South Africa with the objective of characterising milk production and consumption among the communal households. A pretested semi-structured questionnaire was used to collect data through a single visit survey between June 2014 and May 2015. The study was undertaken in five randomly selected communal districts using a multi – stage area probability sampling method. Household sample size was calculated using a statistical methodology through a fixed formula based on a rural population size of 4410000, at a confidence level of 95 percent. A total of 500 households were selected with a sample size of 20 households in 5 communities within five different communal districts within the province. Half of the total sample size was used to represent the number of non-milk producing households (250) to get a true reflection on consumption profiles for nonproducers. Across the province the average communal family size was between 5-10 members with a monthly income of ZAR1340 per household. On average, pasture land size of the sampled households was 1 ha, with a range of 0.25-1.7 ha. The numbers of animals per species found in the studied province was highest for sheep (310) followed by cattle (227) and goat (87). Average livestock holding per household in the study area was 9.85 TLU (Tropical Livestock Unit). According to the respondents the predominant milking livestock numbers were between 1-3 animals milking per household. In the studied area traditional hand milking of livestock was the major milking practices at 12 percent in goats, 15 percent in sheep and 45 percent in cattle milk production. Consumption was the predominant reason for milk production recorded at 27 percent across the province. Milk production was 43 percent most preferred in cattle followed by 32 percent in goat and least at 29 percent in sheep across the province. In general, from the study it was noted that the majority (38 percent) of the respondents across the province indicated 0-5mins as the time it took to milk most milk producing livestock. The majority of the milking practices was done (37 percent) predominantly once a day, followed by 2 percent twice daily across the province. The daily milk production was on average (0.45±1.07) 2-5 litre in cattle, (4.86±0.814) 0-1litre in goats and (2.62±0.42) 0-1 litre sheep per producing house hold with in the province The monthly raw milk consumption in the province was (2.20± 1.42) 2-5 litres of cattle milk, (4.78±0.79) 2-5 litres of goat milk and (4.98±0.69) 2-5 litres of sheep milk per consuming household.
- Full Text:
- Date Issued: 2016
- Authors: Kumbirai, Kaguru Tinashe
- Date: 2016
- Subjects: Milk consumption -- South Africa -- Eastern Cape Dairy farming -- Economic aspects -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/3066 , vital:28251
- Description: The study was conducted in Eastern Cape Province, South Africa with the objective of characterising milk production and consumption among the communal households. A pretested semi-structured questionnaire was used to collect data through a single visit survey between June 2014 and May 2015. The study was undertaken in five randomly selected communal districts using a multi – stage area probability sampling method. Household sample size was calculated using a statistical methodology through a fixed formula based on a rural population size of 4410000, at a confidence level of 95 percent. A total of 500 households were selected with a sample size of 20 households in 5 communities within five different communal districts within the province. Half of the total sample size was used to represent the number of non-milk producing households (250) to get a true reflection on consumption profiles for nonproducers. Across the province the average communal family size was between 5-10 members with a monthly income of ZAR1340 per household. On average, pasture land size of the sampled households was 1 ha, with a range of 0.25-1.7 ha. The numbers of animals per species found in the studied province was highest for sheep (310) followed by cattle (227) and goat (87). Average livestock holding per household in the study area was 9.85 TLU (Tropical Livestock Unit). According to the respondents the predominant milking livestock numbers were between 1-3 animals milking per household. In the studied area traditional hand milking of livestock was the major milking practices at 12 percent in goats, 15 percent in sheep and 45 percent in cattle milk production. Consumption was the predominant reason for milk production recorded at 27 percent across the province. Milk production was 43 percent most preferred in cattle followed by 32 percent in goat and least at 29 percent in sheep across the province. In general, from the study it was noted that the majority (38 percent) of the respondents across the province indicated 0-5mins as the time it took to milk most milk producing livestock. The majority of the milking practices was done (37 percent) predominantly once a day, followed by 2 percent twice daily across the province. The daily milk production was on average (0.45±1.07) 2-5 litre in cattle, (4.86±0.814) 0-1litre in goats and (2.62±0.42) 0-1 litre sheep per producing house hold with in the province The monthly raw milk consumption in the province was (2.20± 1.42) 2-5 litres of cattle milk, (4.78±0.79) 2-5 litres of goat milk and (4.98±0.69) 2-5 litres of sheep milk per consuming household.
- Full Text:
- Date Issued: 2016
Consumer perceptions and microbial quality of meat sold in the informal markets of Nkonkobe and Buffalo City municipalities in the Eastern province, South Africa
- Authors: Mazizi, Bulelani Elvis
- Date: 2016
- Subjects: Meat -- Quality -- South Africa --Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/15365 , vital:40401
- Description: The main objective of the study was to determine consumer perceptions and microbial quality of meat sold in the informal markets found in Nkonkobe and Buffalo City Municipalities in the Eastern Cape Province, South Africa. To determine consumer perceptions of the quality of the meat and meat products sold in the informal markets in Nkonkobe and Buffalo City Municipalities, a survey was conducted. A total of 160 consumers from two municipalities in the Eastern Cape (EC) Province of South Africa was randomly sampled and interviewed. A questionnaire was used to gather information about consumer perceptions of meat and meat products sold in the informal markets regarding their knowledge about safety, food-borne diseases, hygiene, and the quality of the meat among others. The study showed that Alice Town has a larger (66.25percent) proportion of consumers with knowledge about foodborne diseases while King Williams’s Town had a larger proportion (48.75percent) of respondents who had no knowledge about Food-borne diseases. However, a large proportion of consumers in King Williams’s Town considered vendor (82.5percent) and environmental hygiene (93.75percent) than in Alice Town. Consumers (83.75percent) in King Williams’s Town viewed the meat from street vendors to be of low quality while a small proportion (18.75percent) of consumers in Alice Town viewed it as the meat of good quality. Alice had a large proportion (61.25percent) of consumers, which had knowledge of the meat safety law than King Williams’s Town. More consumers from King Williams’s Town (31.25percent) agreed that government plays a role while Alice had a small proportion (26.25percent) which disagreed. The results also showed that consumer perceptions about the safety of meat and meat products are focused more on hygiene, neglecting other important aspects such as vending infrastructure. However, most consumers do not have enough knowledge concerning meat safety. The second study determined the microbial quality of meat sold by street vendors based in Alice and Kind Williams Town in the Eastern Cape Province South Africa. A total of 48 fresh and uncooked meat samples (beef, pork, and mutton), 48 surface contact plates and 40 water samples was collected from 4 street vendors from each town for microbial analysis (n=48). After collection, all samples were subjected to Aerobic plate count (APC), Salmonella spp, Staphylococcus aureus (Staph) and Escherichia coli (E. coli). The results revealed that Salmonella spp tested negative across all the meat samples used in the study. However, no significant differences were found in the microbial quality of meat sold by street vendors in Alice and King Williams town. Furthermore, there were no significant differences (P>0.05) between the APC of raw beef (4.8 Log CFU/g), mutton (3.7 Log CFU/g) and pork (2.8 Log CFU/g) and also the cooked beef (1.5 Log CFU/g), mutton (1.3 Log CFU/g) and pork (1.9 Log CFU/g) samples. A similar trend was observed in the values of Staphylococcus aureus (Staph) and Escherichia coli (E. coli) counts in raw and cooked meat samples. However, a positive correlation between Aerobic plate counts (APC) and Staphylococcus aureus (Staph) (P<0.001) and Escherichia coli (E. coli) (P<0.01) was found in the study. It can, therefore, be concluded that there were no differences in the microbial counts of raw and cooked meat sold in the informal markets of Nkonkobe and Buffalo City Municipalities in the Eastern Cape Province, South Africa.
- Full Text:
- Date Issued: 2016
- Authors: Mazizi, Bulelani Elvis
- Date: 2016
- Subjects: Meat -- Quality -- South Africa --Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/15365 , vital:40401
- Description: The main objective of the study was to determine consumer perceptions and microbial quality of meat sold in the informal markets found in Nkonkobe and Buffalo City Municipalities in the Eastern Cape Province, South Africa. To determine consumer perceptions of the quality of the meat and meat products sold in the informal markets in Nkonkobe and Buffalo City Municipalities, a survey was conducted. A total of 160 consumers from two municipalities in the Eastern Cape (EC) Province of South Africa was randomly sampled and interviewed. A questionnaire was used to gather information about consumer perceptions of meat and meat products sold in the informal markets regarding their knowledge about safety, food-borne diseases, hygiene, and the quality of the meat among others. The study showed that Alice Town has a larger (66.25percent) proportion of consumers with knowledge about foodborne diseases while King Williams’s Town had a larger proportion (48.75percent) of respondents who had no knowledge about Food-borne diseases. However, a large proportion of consumers in King Williams’s Town considered vendor (82.5percent) and environmental hygiene (93.75percent) than in Alice Town. Consumers (83.75percent) in King Williams’s Town viewed the meat from street vendors to be of low quality while a small proportion (18.75percent) of consumers in Alice Town viewed it as the meat of good quality. Alice had a large proportion (61.25percent) of consumers, which had knowledge of the meat safety law than King Williams’s Town. More consumers from King Williams’s Town (31.25percent) agreed that government plays a role while Alice had a small proportion (26.25percent) which disagreed. The results also showed that consumer perceptions about the safety of meat and meat products are focused more on hygiene, neglecting other important aspects such as vending infrastructure. However, most consumers do not have enough knowledge concerning meat safety. The second study determined the microbial quality of meat sold by street vendors based in Alice and Kind Williams Town in the Eastern Cape Province South Africa. A total of 48 fresh and uncooked meat samples (beef, pork, and mutton), 48 surface contact plates and 40 water samples was collected from 4 street vendors from each town for microbial analysis (n=48). After collection, all samples were subjected to Aerobic plate count (APC), Salmonella spp, Staphylococcus aureus (Staph) and Escherichia coli (E. coli). The results revealed that Salmonella spp tested negative across all the meat samples used in the study. However, no significant differences were found in the microbial quality of meat sold by street vendors in Alice and King Williams town. Furthermore, there were no significant differences (P>0.05) between the APC of raw beef (4.8 Log CFU/g), mutton (3.7 Log CFU/g) and pork (2.8 Log CFU/g) and also the cooked beef (1.5 Log CFU/g), mutton (1.3 Log CFU/g) and pork (1.9 Log CFU/g) samples. A similar trend was observed in the values of Staphylococcus aureus (Staph) and Escherichia coli (E. coli) counts in raw and cooked meat samples. However, a positive correlation between Aerobic plate counts (APC) and Staphylococcus aureus (Staph) (P<0.001) and Escherichia coli (E. coli) (P<0.01) was found in the study. It can, therefore, be concluded that there were no differences in the microbial counts of raw and cooked meat sold in the informal markets of Nkonkobe and Buffalo City Municipalities in the Eastern Cape Province, South Africa.
- Full Text:
- Date Issued: 2016
Effect of Moringa oleifera leaf meal on growth performance, faecal ammonia emissions, carcass characteristics and the quality of meat from broiler chickens
- Authors: Mxunyelwa, Avela,
- Date: 2016
- Subjects: Moringa oleifera Meat -- Quality Broilers (Chickens)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/15034 , vital:40154
- Description: The objective of the study was to determine growth performance, faecal ammonia gas emission, carcass characteristics and physico-chemical meat traits from broilers fed one of the four dietary treatments, containing 0percent, 1percent, 3percent or 5percent Moringa oleifera leaf meal (MOLM) (T1, T2, T3, and T4, respectively). Dietary treatments were formulated to be isonitrogenous and isocaloric for a starter (0-14 days), grower (15-21days) and finisher (22-35 days). A total of 160 day old Cobb 500 broiler chickens, initially weighing an average of 45g were randomly allocated to each of the dietary treatments, each with four replicates, in 16 pens. Feed and water were offered ad libitum. Feed intakes (FI), average daily gain (ADG), body weight gain (BWG) and feed conversion efficiency (FCE) were measured weekly. At the end of the feeding trial, the feed was withdrawn from the birds for 12 hours with water available ad libitum and the birds were slaughtered using standard abattoir procedures. The breast muscle of each carcass was sampled for meat quality analysis. Organ and carcass weights differences were measured. Birds fed with T1 had the highest FI. Birds fed with T4 had the best FCE at day 14, 21 and 35. At day 7 and 35, there were no significant differences in FCE in all the treatments. At 0 to 35 days, faecal ammonia emission decreased (P<0.05) as MOLM concentration and age of birds increased. Moringa fed broilers had the highest body weights in all the periods despite the incorporation level in the diet. The results showed that inclusion of MOLM had a significant effect (P<0.05) on the heart, neck, and head weights but had no significant effect on liver, gizzard, intestine and feet. Broilers fed with T1 had heavier heart, neck and head weights compared to MOLM fed broilers. In terms of carcass traits, MOLM had a significant effect (P<0.05) on wings and thighs but had no significant effect (P>0.05) on breast and drumsticks. Moringa oleifera leaf meal had a significant effect on carcass weights, control diet had heavier weights (1185g ± 28.96) compared to chickens fed with MOLM diets (1121g±28.96, 1070g ± 28.96, 1030g± 28.96). Broilers fed with MOLM had higher values of lightness (L*) and (b*) values (P<0.05) at 45 minutes and 24 hours and no difference was observed in redness (a*) at 45 minutes and 24 hours. The L* values dropped at 24 hours for all the treatments and MOLM fed broilers had the lowest values (46.59 ± 0.76,46 ± 0.76,49 ± 0.76) compared to the control diet (50 ± 0.76). The pH levels were comparable after 24 hours; T2 had the highest pH values (5.95 ± 0.024) compared to other treatments (5.90 ± 0.024, 5.75 ± 0.024, 5.73 ± 0.024). The results of this study demonstrated that even though the FI was reduced in MOLM fed broilers, they efficiently consumed and used nutrients, as a result MOLM fed birds had higher weights and low ammonia concentration throughout the experiment, which may improve the house environment without affecting the quality of meat.
- Full Text:
- Date Issued: 2016
- Authors: Mxunyelwa, Avela,
- Date: 2016
- Subjects: Moringa oleifera Meat -- Quality Broilers (Chickens)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/15034 , vital:40154
- Description: The objective of the study was to determine growth performance, faecal ammonia gas emission, carcass characteristics and physico-chemical meat traits from broilers fed one of the four dietary treatments, containing 0percent, 1percent, 3percent or 5percent Moringa oleifera leaf meal (MOLM) (T1, T2, T3, and T4, respectively). Dietary treatments were formulated to be isonitrogenous and isocaloric for a starter (0-14 days), grower (15-21days) and finisher (22-35 days). A total of 160 day old Cobb 500 broiler chickens, initially weighing an average of 45g were randomly allocated to each of the dietary treatments, each with four replicates, in 16 pens. Feed and water were offered ad libitum. Feed intakes (FI), average daily gain (ADG), body weight gain (BWG) and feed conversion efficiency (FCE) were measured weekly. At the end of the feeding trial, the feed was withdrawn from the birds for 12 hours with water available ad libitum and the birds were slaughtered using standard abattoir procedures. The breast muscle of each carcass was sampled for meat quality analysis. Organ and carcass weights differences were measured. Birds fed with T1 had the highest FI. Birds fed with T4 had the best FCE at day 14, 21 and 35. At day 7 and 35, there were no significant differences in FCE in all the treatments. At 0 to 35 days, faecal ammonia emission decreased (P<0.05) as MOLM concentration and age of birds increased. Moringa fed broilers had the highest body weights in all the periods despite the incorporation level in the diet. The results showed that inclusion of MOLM had a significant effect (P<0.05) on the heart, neck, and head weights but had no significant effect on liver, gizzard, intestine and feet. Broilers fed with T1 had heavier heart, neck and head weights compared to MOLM fed broilers. In terms of carcass traits, MOLM had a significant effect (P<0.05) on wings and thighs but had no significant effect (P>0.05) on breast and drumsticks. Moringa oleifera leaf meal had a significant effect on carcass weights, control diet had heavier weights (1185g ± 28.96) compared to chickens fed with MOLM diets (1121g±28.96, 1070g ± 28.96, 1030g± 28.96). Broilers fed with MOLM had higher values of lightness (L*) and (b*) values (P<0.05) at 45 minutes and 24 hours and no difference was observed in redness (a*) at 45 minutes and 24 hours. The L* values dropped at 24 hours for all the treatments and MOLM fed broilers had the lowest values (46.59 ± 0.76,46 ± 0.76,49 ± 0.76) compared to the control diet (50 ± 0.76). The pH levels were comparable after 24 hours; T2 had the highest pH values (5.95 ± 0.024) compared to other treatments (5.90 ± 0.024, 5.75 ± 0.024, 5.73 ± 0.024). The results of this study demonstrated that even though the FI was reduced in MOLM fed broilers, they efficiently consumed and used nutrients, as a result MOLM fed birds had higher weights and low ammonia concentration throughout the experiment, which may improve the house environment without affecting the quality of meat.
- Full Text:
- Date Issued: 2016
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:
- Date Issued: 2016
- 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:
- Date Issued: 2016
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:
- Date Issued: 2016
- 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:
- Date Issued: 2016
Fatty acid composition, colour stability and lipid oxidation of mince produced from fresh and frozen/thawed fallow deer meat
- Authors: Chido, Chakanya
- Date: 2016
- Subjects: Lipids -- Oxidation Meat -- Preservation Mincemeat
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/2479 , vital:27874
- Description: The aim of the study was to determine the fatty acid composition, colour stability and lipid oxidation of fresh mince produced from fallow deer and to evaluate the effect of frozen storage duration on the retail display shelf life of the mince. A total of 31 fallow deer carcasses were used in the study. After cooling for 24hrs, the carcasses were deboned, external fat from the fore and hindquarter muscles removed and individually vacuum packed. For the first trial, seven fallow deer carcasses were used. Meat from the hind and fore-quarters of each carcass was divided into two equal batches per animal. One batch was minced (through a 5 mm die) and packed into oxygen permeable overwraps and refrigerated at 4°C for a period of eight days under retail display conditions. The second batch was vacuum packed and frozen at -20°C for 2 months at the end of which mince was also produced and monitored over an eight-day period under the same conditions that were used for the fresh mince. Colour, pH, lipid and myoglobin stability was determined. Proximate and fatty acid composition was also determined. No differences (P>0.05) were noted between proximate composition of fresh and frozen/thawed minced meat. The lipid content of fallow deer was 2.4 percent (±0.04). Total n3 fatty acids differed (P<0.05) between treatments and decreased with increased storage and display day. There were significant (P<0.05) treatment and time interactions on all measured colour parameters, TBARS and myoglobin forms. Fresh mince was lighter and had higher redness (a*) and yellowness (b*) values than mince from two months frozen stored meat. Hue angle for fresh mince remained stable throughout display whereas it increased for frozen/thawed mince. Fresh mince had lower TBARS values than frozen/thawed mince. Minced meat produced from frozen/thawed deer meat had higher surface met-myoglobin and total met-myoglobin percentages. Surface and total oxy-myoglobin percentage was higher in fresh mince. The first trial clearly showed colour and lipid stability differences between fresh mince and mince from frozen/thawed meat. It also showed that fresh mince has a longer retail display life than mince produced from frozen/thawed meat (six days and four days, respectively). In the second trial, the effects of frozen storage duration on colour and lipid stability were investigated. Twenty-four fallow deer were used. Twelve were harvested in June (6male 6female) and the other twelve in August (6 male 6female) of the same year.Twenty four hours after harvesting, the fore and hindquarter muscles of the carcasses were deboned, vacuum packed and kept at -20°C until October (i.e. 2months and 4months frozen storage period). Upon thawing, the meat was processed into mince following the same procedure used for the first trialand displayed for a fiveday period under retail display conditions. Frozen duration and gender had no effect (P>0.05) on the proximate composition of fallow deer meat. The total amount of saturated fatty acids (SFA) increased and total amount of poly unsaturated fatty acids (PUFA) decreased as frozen duration and display day increased (P<0.05). Frozen duration affected (P<0.01) lipid oxidation and percentage oxy-myoglobin. Mince pH and all colour parameters (L*, a*, b*,hue and chroma) differed (P<0.05) between treatments on day zero and three. Display day was a significant factor (P<0.05) on all measured parameters. By day three all parameters except pH showed signs of extended oxidation and discolouration as evidenced by reduced redness, decreased colour intensity and high TBARS values. This study showed that prolonged frozen storage negatively affects the colour and lipid stability of meat and increases oxidation of PUFAs during frozen storage. However, the study also suggests that although frozen/thawed meat has a shorter retail display shelf life; the proximate composition of the meat remains unchanged.
- Full Text:
- Date Issued: 2016
- Authors: Chido, Chakanya
- Date: 2016
- Subjects: Lipids -- Oxidation Meat -- Preservation Mincemeat
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/2479 , vital:27874
- Description: The aim of the study was to determine the fatty acid composition, colour stability and lipid oxidation of fresh mince produced from fallow deer and to evaluate the effect of frozen storage duration on the retail display shelf life of the mince. A total of 31 fallow deer carcasses were used in the study. After cooling for 24hrs, the carcasses were deboned, external fat from the fore and hindquarter muscles removed and individually vacuum packed. For the first trial, seven fallow deer carcasses were used. Meat from the hind and fore-quarters of each carcass was divided into two equal batches per animal. One batch was minced (through a 5 mm die) and packed into oxygen permeable overwraps and refrigerated at 4°C for a period of eight days under retail display conditions. The second batch was vacuum packed and frozen at -20°C for 2 months at the end of which mince was also produced and monitored over an eight-day period under the same conditions that were used for the fresh mince. Colour, pH, lipid and myoglobin stability was determined. Proximate and fatty acid composition was also determined. No differences (P>0.05) were noted between proximate composition of fresh and frozen/thawed minced meat. The lipid content of fallow deer was 2.4 percent (±0.04). Total n3 fatty acids differed (P<0.05) between treatments and decreased with increased storage and display day. There were significant (P<0.05) treatment and time interactions on all measured colour parameters, TBARS and myoglobin forms. Fresh mince was lighter and had higher redness (a*) and yellowness (b*) values than mince from two months frozen stored meat. Hue angle for fresh mince remained stable throughout display whereas it increased for frozen/thawed mince. Fresh mince had lower TBARS values than frozen/thawed mince. Minced meat produced from frozen/thawed deer meat had higher surface met-myoglobin and total met-myoglobin percentages. Surface and total oxy-myoglobin percentage was higher in fresh mince. The first trial clearly showed colour and lipid stability differences between fresh mince and mince from frozen/thawed meat. It also showed that fresh mince has a longer retail display life than mince produced from frozen/thawed meat (six days and four days, respectively). In the second trial, the effects of frozen storage duration on colour and lipid stability were investigated. Twenty-four fallow deer were used. Twelve were harvested in June (6male 6female) and the other twelve in August (6 male 6female) of the same year.Twenty four hours after harvesting, the fore and hindquarter muscles of the carcasses were deboned, vacuum packed and kept at -20°C until October (i.e. 2months and 4months frozen storage period). Upon thawing, the meat was processed into mince following the same procedure used for the first trialand displayed for a fiveday period under retail display conditions. Frozen duration and gender had no effect (P>0.05) on the proximate composition of fallow deer meat. The total amount of saturated fatty acids (SFA) increased and total amount of poly unsaturated fatty acids (PUFA) decreased as frozen duration and display day increased (P<0.05). Frozen duration affected (P<0.01) lipid oxidation and percentage oxy-myoglobin. Mince pH and all colour parameters (L*, a*, b*,hue and chroma) differed (P<0.05) between treatments on day zero and three. Display day was a significant factor (P<0.05) on all measured parameters. By day three all parameters except pH showed signs of extended oxidation and discolouration as evidenced by reduced redness, decreased colour intensity and high TBARS values. This study showed that prolonged frozen storage negatively affects the colour and lipid stability of meat and increases oxidation of PUFAs during frozen storage. However, the study also suggests that although frozen/thawed meat has a shorter retail display shelf life; the proximate composition of the meat remains unchanged.
- Full Text:
- Date Issued: 2016
Management factors influencing lamb survival from birth to weaning in two ecologically different resource-limited communal farming systems
- Authors: Lungu, Nobuhle
- Date: 2016
- Subjects: Lambs Communal rangelands Lambs--Feeding and feeds
- Language: English
- Type: Thesis , Masters , Animal Science
- Identifier: http://hdl.handle.net/10353/11806 , vital:39108
- Description: The objective of the study was to determine the management factors influencing lamb survival from birth to weaning in two ecologically different resource-limited communal farming systems. An annual flock monitoring study in the sourveld and sweetveld regions was preceded by a household check-all-that-apply (CATA). Lamb management practices and constraints faced in raising lambs in the two regions were determined using the check-all-that-apply technique. The results showed that the majority of the households were male headed (75.70percent) and consisted of the elderly (˃50 years, 79.44percent) who were not employed (82.24percent) and had attended primary school (67.29percent). Wool production was ranked the most important reason for keeping sheep in the two regions. The CATA revealed that the management systems between the two regions differed significantly (p˂0.05) in terms of assisting sheep at lambing, attending to twin births and dipping of mature lambs. Farmers‘ age was associated with the type of management performed (p ˂0.05). None of the farmers in the two regions performed navel dipping. Some of the reported constraints in the sweetveld were theft, diarrhoea and drought while predators and cold weather were the major constraints in the sourveld. The CATA identified vaccination and dipping as the major missing practices in both regions. The study showed differences in the use and choice of CATA terms which suggests that a ―one-size-fits-all‖ approach to solving poor management and sheep production constraints is not applicable. In the monitoring study, the results showed that veld type had no significant effect on the birth weights (2.0±0.09 kg) of the lambs. Type of birth had a significant effect (p<0.05) on the birth weights of the lambs. Single born lambs were 0.41kg heavier (p<0.05) than twin lambs. Single born lambs, however, showed an improvement in weights at 90 and 120 days where they had slightly higher weights than single born lambs. Male lambs were significantly (p<0.05) heavier (2.3±0.12 kg) than the female lambs (1.7±0.06 kg) at birth. The lamb birth were highest (P<0.05) in the hot-dry season. Lambs born in the cold-dry season were the lightest (1.63±0.13 kg). Lambs born in the post- rainy and hot-wet season were not significantly different (P<0.05). Weaning weights were not affected by veld type, birth type and sex, but were affected by season of birth. The lambs born in the hot-dry season had the highest weaning weights. The sourveld had a total pre-weaning mortality of 10.6percent while the sweetveld had a total pre-weaning mortality of 14.2percent. Animal housing from both veld types was poorly designed in terms of security against stock theft, drainage, hygiene, overhead shelter from the rain as well as access to feed and water. It was concluded that lamb management practices in the two regions were not the same. Performance of lambs before weaning differed according to veld type which played a role in feed availability during different seasons.
- Full Text:
- Date Issued: 2016
- Authors: Lungu, Nobuhle
- Date: 2016
- Subjects: Lambs Communal rangelands Lambs--Feeding and feeds
- Language: English
- Type: Thesis , Masters , Animal Science
- Identifier: http://hdl.handle.net/10353/11806 , vital:39108
- Description: The objective of the study was to determine the management factors influencing lamb survival from birth to weaning in two ecologically different resource-limited communal farming systems. An annual flock monitoring study in the sourveld and sweetveld regions was preceded by a household check-all-that-apply (CATA). Lamb management practices and constraints faced in raising lambs in the two regions were determined using the check-all-that-apply technique. The results showed that the majority of the households were male headed (75.70percent) and consisted of the elderly (˃50 years, 79.44percent) who were not employed (82.24percent) and had attended primary school (67.29percent). Wool production was ranked the most important reason for keeping sheep in the two regions. The CATA revealed that the management systems between the two regions differed significantly (p˂0.05) in terms of assisting sheep at lambing, attending to twin births and dipping of mature lambs. Farmers‘ age was associated with the type of management performed (p ˂0.05). None of the farmers in the two regions performed navel dipping. Some of the reported constraints in the sweetveld were theft, diarrhoea and drought while predators and cold weather were the major constraints in the sourveld. The CATA identified vaccination and dipping as the major missing practices in both regions. The study showed differences in the use and choice of CATA terms which suggests that a ―one-size-fits-all‖ approach to solving poor management and sheep production constraints is not applicable. In the monitoring study, the results showed that veld type had no significant effect on the birth weights (2.0±0.09 kg) of the lambs. Type of birth had a significant effect (p<0.05) on the birth weights of the lambs. Single born lambs were 0.41kg heavier (p<0.05) than twin lambs. Single born lambs, however, showed an improvement in weights at 90 and 120 days where they had slightly higher weights than single born lambs. Male lambs were significantly (p<0.05) heavier (2.3±0.12 kg) than the female lambs (1.7±0.06 kg) at birth. The lamb birth were highest (P<0.05) in the hot-dry season. Lambs born in the cold-dry season were the lightest (1.63±0.13 kg). Lambs born in the post- rainy and hot-wet season were not significantly different (P<0.05). Weaning weights were not affected by veld type, birth type and sex, but were affected by season of birth. The lambs born in the hot-dry season had the highest weaning weights. The sourveld had a total pre-weaning mortality of 10.6percent while the sweetveld had a total pre-weaning mortality of 14.2percent. Animal housing from both veld types was poorly designed in terms of security against stock theft, drainage, hygiene, overhead shelter from the rain as well as access to feed and water. It was concluded that lamb management practices in the two regions were not the same. Performance of lambs before weaning differed according to veld type which played a role in feed availability during different seasons.
- Full Text:
- Date Issued: 2016
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
- Date Issued: 2016
- 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
- Date Issued: 2016
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:
- Date Issued: 2016
- 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:
- Date Issued: 2016
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