Thesis (M.Sc) (Agriculture)--University of Limpopo,2007. / Two experiments were carried out to evaluate the effects of feed restriction during the starter stage and lysine supplementation during realimentation on productivity and carcass characteristics of Ross 308 broiler chickens. In the first experiment, the effects of level and period of feed restriction during the starter period on subsequent productivity were evaluated. A 2 (male and female chickens) x 3 (feeding levels, ad libitum and 75% and 50% of ad libitum) x 3 (restriction periods of 5, 7 and 9 days), factorial arrangement in a Completely Randomized Design was used. The effects interactions were not included in the results because earlier analyses including all the interactions showed that they were not important. Level and period of feed restriction during the starter stage had an effect (P<0.05) on live weight of the chickens at 21 days of age. However, female and male chickens had similar live weights at 21 days of age. Chickens on 75% ad libitum feeding attained complete live weight compensation at the age of 42 days. However, chickens on 50% ad libitum feeding did not ‘catch-up’ with those on ad libitum feeding. Differences due to the period of feed restriction during the starter stage were maintained up to the age of 42 days. Male chickens had higher (P<0.05) live weights at 42 days of age. Abdominal fat pad was not affected (P>0.05) by level and period of feed restriction and sex of chickens at 42 days of age. The second experiment evaluated the effects of feed restriction during the starter stage (14 to 21 days) and levels of lysine supplementation during realimentation (21 to 42 days) on productivity and carcass characteristics of male and female chickens. Feed v restriction affected (P<0.05) live weight of chickens at the age of 21 days and males were heavier (P<0.05) than females at the same age. Chickens on 75% ad libitum feeding attained complete compensation in live weight while those on 50% ad libitum feeding did not. Lysine supplementation during realimentation had no effects (P>0.05) on live weight and carcass characteristics of the chickens at 42 days of age. Male chickens attained higher (P<0.05) live weights than female chickens at 42 days of age. / National Research Foundation

Thesis (M.Sc. (Animal Production)) --University of Limpopo, 2018. / Refer to the document

Thesis (M.Sc. (Animal Production)) -- University of Limpopo, 2014 / Two experiments were conducted to determine the effects of supplementing diets with effective microorganisms on intake, growth and carcass characteristics of Ross 308 broiler chickens. The first experiment determined the effect of supplementing diets with effective microorganisms on performance of unsexed Ross 308 broiler chickens aged one to three weeks. Two hundred unsexed day-old chicks were randomly assigned to five treatments with four replications, each replication having ten birds. A complete randomized design was used. The chickens were fed a grower diet supplemented with 0 (EM0), 30 (EM30), 50 (EM50), 70 (EM70) or 100 (EM100) ml of effective microorganisms per litre of water. Effective microorganism supplementation did not improve (P>0.05) diet and metabolisable energy intakes of the chickens. Effective microorganism supplementation reduced (P<0.05) growth rate and live weight of the chickens. Poorer (P<0.05) feed conversion ratios were observed in chickens supplemented with effective microorganisms. However, effective microorganism supplementation improved (P<0.05) crude protein retention of the chickens. Supplementation with effective microorganisms reduced (P<0.05) mortality rate of the chickens from 10 to 0 %. The second experiment determined the effect of supplementing diets with effective microorganisms on performance of male Ross 308 broiler chickens aged 22 to 42 days. The chickens were randomly allocated to five treatments with four replications, each replication having 10 birds. The chickens aged 21 days, weighing 474 ± 2g, were allocated to the treatments in a complete randomized design. The chickens were fed a grower diet supplemented with 0 (EMM0), 30 (EMM30), 50 (EMM50, 70 (EMM70) or 100 (EMM100) ml of effective microorganisms per litre of water. Effective microorganism supplementation did not improve (P>0.05) intake, DM digestibility, metabolisable energy, feed conversion ratio, fat pad weight and meat sensory attributes of the chickens. Effective microorganism supplementation reduced (P<0.05) growth rate, live weight and carcass weight of the chickens. However, effective microorganism supplementation improved (P<0.05) crude protein retention and crude protein content of meat of the chickens. Supplementation with effective microorganisms reduced (P<0.05) mortality of the chickens from 5 to 0 %. v It is concluded that effective microorganism supplementation to the diets of Ross 308 broiler chickens reduced growth rate and live weight of the chickens. However, effective microorganism supplementation improved crude protein retention and crude protein content of the meat of broiler chickens. Supplementation with effective microorganisms reduced mortality of the chickens to zero.

Thesis (M.A. (Agricultural Management) -- University of Limpopo, 2020 / Two experiments were conducted to determine the effect of natuzyme50® supplementation on fibre digestion, growth and carcass characteristics of Ross 308 broiler chickens aged one to 42 days. The first experiment determined the effect of natuzyme50® supplementation on feed intake, growth and live weight of unsexed Ross 308 broiler chickens aged one to 21 days. Unsexed day old chicks were assigned to 4 different natuzyme50® supplementation levels of 0.0 (UNZ0), 0.75 (UNZ0.75), 1.0 (UNZ1.0) and 1.5 (UNZ1.5) g/kg DM feed, replicated 4 times and each replicate having 10 chicks. A general linear model (SAS, 2008) was used to analyse the data. Ross 308 broiler chickens on a diet supplemented with 1.5g of natuzyme50® per kg DM had higher (P<0.05) DM feed intake than those on a diet not supplemented with natuzyme50®. Natuzyme50® supplementation did not (P>0.05) have any significant effect on growth rate of unsexed Ross 308 broiler chickens aged one to 21 days. Unsexed broiler chickens on a diet supplemented with 1.5g of natuzyme50® per kg DM had higher (P<0.05) live weights than those on a diet not supplemented with natuzyme50® at the age of 21 days The second experiment determined the effect of natuzyme50® supplementation on feed intake, growth performance and carcass characteristics of male Ross 308 broiler chickens aged 22 to 42 days. The chickens aged 22 days were assigned to 4 natuzyme50® supplementation levels of 0.0 (MNZ0), 0.75 (MNZ0.75), 1.0 (MNZ1.0) and 1.5 (MNZ1.5) g/kg DM feed, replicated 4 times and each replicate having 6 chickens. The diets were isocaloric and isonitrogenous. A general linear model (SAS, 2008) was used to analyse the data obtained. Natuzyme50® supplementation level had no effect (P>0.05) on feed intake of male Ross 308 broiler chickens aged 22 to 42 days. However, natuzyme50® supplementation level had effect (P<0.05) on growth rate of male Ross broiler chickens aged 22-42 days. Male Ross 308 broiler chickens on a diet supplemented with 1.5g of natuzyme50® per kg DM had higher (P<0.05) growth rates than those on a diet supplemented with 1.0g of natuzyme50® per kg DM. However, the significant differences did not extend to birds on a diet not supplemented with natuzyme50®, diets supplemented with 0.75 or 1.5g of natuzyme50® per kg DM which vi showed similar (P>0.05) growth rates. Natuzyme50® supplementation levels used had no effect (P>0.05) on carcass, breast and drumstick weights of male Ross 308 broiler chickens. Natuzyme50® supplementation levels had no effect (P>0.05) on meat juiciness. However, natuzyme50® supplementation improved (P<0.05) meat tenderness and flavour. Increasing natuzyme50® level of supplementation decreased (P<0.05) meat shear force values. It is concluded that natuzyme50® supplementation improved (P<0.05) meat tenderness and flavour, and reduced meat shear force values of male Ross 308 broiler chickens. However, further studies are recommended to ascertain the current results. / Edu-loan

Thesis (M. Sc. Agriculture (Animal Production)) -- University of Limpopo, 2019 / Two experiments were conducted to determine the effect of dietary methionine level on productivity and carcass characteristics of Ross 308 broiler chickens. In each experiment, the diets were isocaloric and isonitrogenous but with different dietary methionine levels. Five diets were formulated to contain dietary methionine levels of 4, 5, 6, 8 or 9g/kg DM. The first experiment commenced with 300 unsexed Ross 308 broiler chickens with initial average live weights of 42 ± 2g per chicken. The chickens were randomly assigned to five treatments with five replications, resulting in 25-floor pens with 12 chickens per replicate. The second experiment commenced with 150 male Ross 308 broiler chickens with initial average live weight of 637 ± 12g per chicken. The chickens were randomly assigned to five treatments with three replications, resulting in 15-floor pens with 10 chickens per replicate. A complete randomized design was used in each experiment. Data was analysed using the General Linear Model (GLM) procedures of the statistical analysis of variance, Version 9.3.1 software program. Where there were significant differences, mean separation was done using the Tukey test at the 5% level of significance. A quadratic regression model was used to determine the optimal productivity of the chickens while a linear model was used to determine the relationships between dietary methionine level and responses by the chickens in the variables measured. The treatments for the first experiment were UM4 (4g methionine/kg DM), UM5 (5g methionine/kg DM), UM6 (6g methionine/kg DM), UM8 (8g methionine/kg DM) and UM9 (9g methionine/kg DM). Feed intake, growth rate, feed conversion ratio (FCR), metabolisable energy intake and nitrogen retention of unsexed Ross 308 broiler chickens aged one to 21 days were not affected (P>0.05) by dietary methionine level. Similarly, dietary methionine level did not have any effect (P>0.05) on diet crude protein (CP), acid detergent fibre (ADF), neutral detergent fibre (NDF) and fat digestibilities in unsexed Ross 308 broiler chickens aged 14 to 21 days. Dietary methionine level did not have any effect on live weights of broiler chickens at 21 days. Live weights of unsexed Ross 308 broiler chickens aged 7 or 14 days were not improved (P>0.05) by increasing dietary methionine level from 4 to 9g/kg DM. Crop, gizzard and small intestine weights and crop, proventriculus and gizzard digesta pH values of unsexed Ross 308 broiler chickens aged 21 days were not affected v (P>0.05) by dietary methionine level. Similarly, dietary methionine level did not improve (P>0.05) caecum and large intestine lengths of unsexed Ross 308 broiler chickens aged 21 days. However, dietary methionine level affected (P<0.05) dry matter (DM) and ash digestibilities of unsexed Ross 308 broiler chickens aged 14 to 21 days. Proventriculus and large intestine weights, gastrointestinal tract and small intestine lengths of unsexed Ross 308 broiler chickens aged 21 days were improved (P<0.05) by increasing dietary methionine level. In addition, increasing dietary methionine level increased (P<0.05) small and large intestine digesta pH values of broiler chickens aged 21 days. Thus, dry matter digestibility, live weights at day 7 ad 14, caecum length, large intestine length and digesta pH were optimized at different dietary methionine levels of 7.26, 5.29, 4.99, 6.80, 4.84 and 6.37g/kg DM feed, respectively. The treatments for the second experiment were MM4 (4g methionine/kg DM), MM5 (5g methionine/kg DM), MM6 (6g methionine/kg DM), MM8 (8g methionine/kg DM) and MM9 (9g methionine/kg DM). Dietary methionine level did not have effect (P>0.05) on feed intake of male Ross 308 broiler chickens aged 6 weeks. However, dietary methionine level improved (P<0.05) feed intake of male Ross 308 broiler chickens aged 4 or 5 weeks. Live weights of male Ross 308 broiler chickens aged 28 days were not affected (P>0.05) by dietary methionine level. However, live weights of male Ross 308 broiler chickens aged 35 and 42 days were affected (P<0.05) by dietary methionine level. Similarly, dietary methionine level affected (P<0.05) DM, CP, ADF, NDF, fat and ash digestibilities of male Ross 308 broiler chickens aged 35 to 42 days. Thus, dietary methionine levels of 6.93, 7.70, 6.85 and 11.27g/kg DM optimized dry matter, CP and fat digestibilities, and live weight of male broiler chickens aged 42 days. Dietary methionine level did not affect (P>0.05) FCR, growth rate and metabolisable energy intakes of male Ross 308 broiler chickens. Increasing dietary methionine level from 4 to 9g/kg DM improved (P<0.05) nitrogen retention of male Ross 308 broiler chickens aged 22 to 42 days. Dietary methionine level did not have any effect (P>0.05) on proventriculus, gizzard, caecum and large intestine weights, caecum, small and large intestine lengths, and crop, gizzard, caecum and large intestine digesta pH values of male Ross 308 broiler chickens aged 42 days. Crop and small vi intestine weights and gastrointestinal tract lengths of male Ross 308 broiler chickens aged 42 days were improved (P<0.05) by dietary methionine level. Similarly, dietary methionine level affected (P<0.05) proventriculus and small intestine digesta pH values of male Ross 308 broiler chickens aged 42 days. Thus, dietary methionine levels of 6.558 and 7.851g/kg DM optimized broiler chicken crop weight and GIT length. Dietary methionine level affected (P<0.05) carcass organ weights of male Ross 308 broiler chickens aged 42 days. Increasing dietary methionine level increased chicken breast meat weight. However, there was no clear trend for the other carcass organs. Meat flavour and shear force values of male Ross 308 broiler chickens aged 42 days were not affected (P>0.05) by dietary methionine level. However, dietary methionine level affected meat tenderness and juiciness. Thus, dietary methionine levels of 10.09 and 13.32g/kg DM optimized broiler chicken meat tenderness and juiciness. . / National Research Foundation (NRF) and VLIROUS

Thesis (M. Sc. Agriculture (Animal Production)) -- University of Limpopo, 2021 / Two experiments were conducted to determine the effect of replacing soya bean meal with yellow mealworm larvae meal (Tenebrio molitor) in a diet on productivity, gut morphology, carcass characteristics and bone morphometrics of Ross 308 broiler chickens aged one to 42 days. In each experiment, a total of 360 Ross 308 broiler chickens were randomly assigned to the five dietary treatments, each treatment having four replications, and 18 chickens per replicate. Five diets were formulated to contain yellow mealworm replacement levels at 0, 25, 50, 75 and 100% to meet the nutrient requirements of Ross 308 broiler chickens. Data was analysed using the General Linear Model procedures of the Statistical Analysis System, Version 9.3.1 software program. Fisher’s least significant difference (LSD) test was applied for mean separation where there were significant differences (P<0.05). A quadratic regression model was used to determine the levels for optimal responses in the variables measured. The first experiment determined the effect of replacing soya bean meal with yellow mealworm larvae meal on productivity and gut morphology of unsexed Ross 308 broiler chickens aged one to 21 days. Replacement of soya bean meal with yellow mealworm meal in a diet had no effect (p > 0.05) on feed intake, growth rate, FCR, live body weight, ME intake and nitrogen retention of unsexed Ross 308 broiler chickens aged one to 21 days. Replacing soya bean meal with yellow mealworm meal in a diet did not affect (p > 0.05) caecum weight of unsexed Ross 308 broiler chickens. However, replacing soya bean meal with yellow mealworm meal in a diet increased (p < 0.05) gastro intestinal tract, crop, ileum and large intestine weights. Crop and ileum lengths of unsexed Ross 308 broiler chickens aged 21 days were not affected (p > 0.05) by replacement of soya bean meal with yellow mealworm meal in the diet. However, replacing soya bean meal with yellow mealworm meal in a diet increased (p < 0.05) gizzard, caecum and large intestine lengths of unsexed Ross 308 broiler chickens aged 21 days. Yellow mealworm meal in a diet did not affect (p > 0.05) gut organ digesta pH values of unsexed Ross 308 broiler chickens aged 21 days. The second experiment determined the effect of replacing soya bean meal with yellow mealworm meal in a diet on productivity, gut morphology, carcass characteristics and bone morphometrics of Ross 308 broiler chickens aged 22 to 42 days. Replacement of soya bean meal with yellow mealworm meal in a diet did not affect (p > 0.05) growth rate, FCR, ME intake and nitrogen retention of male Ross 308 broiler chickens aged 22 to 42 days. However, replacing soya bean meal with yellow mealworm meal in a diet affected (p < 0.05) feed intake and live body weight of male Ross 308 broiler chickens aged 22 to 42 days. Broiler chickens on diets containing 75 or 100% yellow mealworm meal had higher (p < 0.05) intakes than those on diets containing no yellow mealworm meal. Similarly, male broiler chickens on diets having 50% yellow mealworm meal had higher (p < 0.05) live body weights than those on diets containing no yellow mealworm. Quadratic equations indicated that feed intake and live body weight of male Ross 308 broiler chickens were optimized at yellow mealworm meal replacement levels of 13 and 61%, respectively. The present study showed that replacing soya bean meal with yellow mealworm meal in a diet did not affect (p > 0.05) gut organ digesta pH values, gut organ weights, gut organ lengths, meat colour, meat pH values, bone morphometric values, carcass part weights and meat sensory attributes of male Ross 308 broiler chickens aged 42 days. However, meat from chickens on diets containing yellow mealworm meal was softer (p < 0.05) than meat from chickens on diets having 100% soya bean meal. It is concluded that soya bean meal can be replaced with yellow mealworm larvae meal in a diet at 25, 50, 75 and 100% levels without having adverse effects on production and carcass characteristics of Ross 308 broiler chickens aged one to 42 days