Thesis (M.Sc. (Animal Production)) --University of Limpopo, 2010 / A study was conducted to determine the effect of vitamin E supplementation to the diets of Venda hens on egg production, hatchability and chick productivity. The first part of the study determined the effect of vitamin E supplementation to the diets of Venda hens on feed intake, number of eggs, egg weight, egg content, egg hatchability and chick hatch-weight. Supplementation levels of 0, 200, 400, 800 and 1000 mg of vitamin E per kg DM feed were used in a completely randomized design having five replications with two birds per replicate. Vitamin E supplementation did not have any effect (P<0.05) on number of eggs and feed intake of Venda hens. However, egg weight, egg content, hatchability and chick hatch-weight of Venda chickens improved (P<0.05) with vitamin E supplementation. Dietary vitamin E supplementation values for optimal egg white weight, egg yolk nitrogen content, egg white nitrogen content, egg hatchability and number of eggs were 476 (r2 = 0.756), 750 (r2 = 0.170), 750 (r2 = 0.182), 445 (r2 = 0.670) and 113 (r2=0.966) mg of vitamin E per kg DM feed, respectively. The second part of the study determined the effect of vitamin E supplementation to the diets of Venda hens on performance of their progenies between one and seven weeks old. A completely randomized design was used. All the chickens were fed the same commercial grower diet. Dietary vitamin E supplementation to the diets of Venda hens had no effect (P<0.05) on growth rate and mortality of their progenies between one and seven weeks. Feed intake, feed conversion ratio and live weight of progenies improved (P<0.05) with supplementation of vitamin E to the diets of Venda hens. Dietary vitamin E supplementation to the diets of Venda hens did not have any effect (P<0.05) on dry matter intake, dry matter digestibility, nitrogen retention and metabolisable energy of their progenies at seven weeks old. vi The third part of the study determined the effect of vitamin E supplementation to the diets of Venda hens on performance of their male progenies aged between eight and 13 weeks. A completely randomized design was used. All the chickens were fed the same commercial grower diet. Vitamin E supplementation to the diets of Venda hens did not improve (P<0.05) feed intake, growth rate, feed conversion ratio, live weight and mortality of their male progenies between eight and 13 weeks old. However, Venda hens supplemented with vitamin E produced male progenies with improved (P<0.05) dry matter intake, digestibility, nitrogen retention metabolisable energy, breast meat nitrogen content, gizzard weight, liver weight and heart weight at 13 weeks old. Carcass weight, breast meat yield, drum stick, thigh and wing weight of chickens at 13 weeks old were not affected (P>0.05) by vitamin E supplementation to the diets of the hens It is concluded that supplementation of vitamin E to the diets of indigenous Venda hens improved (P<0.05) egg weight, egg content and chick hatch-weight during the laying period. Vitamin E supplementation to the diets of Venda hens improved (P<0.05) feed intake, live weight, feed conversion ratio, gizzard and liver weight of their progenies. Production variables were optimized at different levels of vitamin E supplementation. Thus, this study provided new information on the effect of vitamin E supplementation to the diets of indigenous Venda hens on chick productivity and carcass characteristics of their progenies.

Thesis (Ph. D. (Animal Production )) -- University of Limpopo, 2013 / Eight experiments were conducted to determine the effect of dietary lysine to energy ratio on the productivity and carcass characteristics of indigenous Venda chickens aged one to thirteen weeks and raised in closed confinement. The eight experiments were based on four different energy levels of 11, 12, 13 and 14 MJ of ME/kg DM. Each dietary energy level had four different levels of dietary lysine (8, 9, 11 and 14 g lysine/kg DM). Thus, different dietary lysine to energy ratios were calculated. Experiments 1 to 4 determined the effect of dietary lysine to energy ratio on productivity of unsexed Venda chickens aged one to seven weeks. Each experiment commenced with 160 unsexed day-old indigenous Venda chicks with an initial live weight of 30 ± 3 g per bird and was carried out for seven weeks. In each experiment, the chicks were randomly assigned to four treatments with four replications, each having 10 chicks. A complete randomized design was used for each experiment. All data were analysed by one-way analysis of variance. Where there were significant differences, the Duncan test for multiple comparisons was used to test the significance of differences between treatment means. A quadratic regression model was used to determine the ratios for optimum productivity in each experiment while a linear model was used to determine the relationships between dietary lysine to energy ratio and optimal responses in the variables measured. Results indicated that dietary lysine to energy ratio for optimal responses depended on the variable of interest. In Experiment 1, feed intake, growth rate, live weight, ME intake and nitrogen retention were optimized at different dietary lysine to energy ratios of 0.722, 0.719, 0.719, 0.670 and 0.712, respectively. There was a positive and strong relationship (r2 = 0.950) between dietary lysine to energy ratio and feed conversion ratio (FCR). Results from Experiment 2 indicated that feed intake, growth rate, FCR, live weight, ME intake and nitrogen retention were optimized at dietary lysine to energy ratios of 0.719, 0.742, 0.788, 0.742, 0.734 and 0.789, respectively. In Experiment 3, dietary lysine to energy ratio did not have any effect (P>0.05) on all the parameters measured. However, quadratic analysis indicated that dietary lysine to energy ratios of 0.817, 0.883, 0.920, 0.898, 0.895 and 0.955 optimized feed intake, growth rate, FCR, live weight, ME intake and nitrogen retention of the chickens, respectively. Experiment 4 results showed that feed intake, growth rate, FCR, live weight ME intake and nitrogen retention were v optimized at different dietary lysine to energy ratios of 0.906, 0.964, 1.023, 0.966, 0.963 and 0.951, respectively. Experiments 5 to 8 determined the effect of dietary lysine to energy ratio on productivity, carcass characteristics, sensory attributes and haematological values of female indigenous Venda chickens aged eight to thirteen weeks. The layouts, treatments, design and execution were similar to those described for Experiments 1, 2, 3 and 4, respectively, except that Experiments 5 to 8 were for female indigenous Venda chickens aged eight to 13 weeks. These chickens were different from those used in Experiments 1 to 4. They were raised on a grower mash (16 % crude protein, 11 MJ of ME/kg DM and 180 g of lysine) prior to commencement of the study. Each experiment commenced with 120 eight weeks old female Venda chickens with an initial live weight of 412 ± 3 g per chicken. In each experiment, the chickens were randomly assigned to four treatments with five replicates, each having six chickens. Results obtained from Experiment 5 showed that feed intake, growth rate, FCR, live weight, ME intake, carcass weight, dressing percentage, breast meat, drumstick, wing weight, breast meat drip loss, juiciness, flavour, haemoglobin and pack cell volume were optimized at different dietary lysine to energy ratios of 0.672, 0.646, 0639, 0.649, 0.655, 0.656, 0.664, 0.669, 0.665, 0.663, 0.631, 0.708, 0.623, 0.556 and 0.609, respectively. In Experiment 6, the diets were formulated to have higher lysine to energy ratios than those in Experiment 5 by using a dietary lysine level of 9 g lysine/kg DM. Results from this experiment showed that feed intake, FCR, nitrogen retention, carcass weight, dressing percentage, breast meat, gizzard weights and breast meat pH at 2, 12 and 24 hours after slaughter were optimized at dietary lysine to energy ratios of 0.798, 0.613, 0.777, 0.742, 0.753, 0.729, 0.758, 0.752, 0.802 and 0.797, respectively. Red blood cell and haemoglobin values in this experiment were optimized at dietary lysine to energy ratios of 0.480 and 0.624, respectively. In Experiment 7, dietary lysine to energy ratios of 0.79, 0.85, 0.92 and 1.00 g lysine/ MJ of ME were used. Dietary treatments in this experiment had no effect (P>0.05) on all the production parameters measured except feed and apparent metabolisable energy intakes. Quadratic analysis of the results indicated that dietary lysine to energy ratios of 0.964, 0.912, 0.900, 0.890, 0.910, 1.090, 0.934 and 0.895 optimized feed intake, apparent metabolisable energy, carcass, breast meat, drumstick weights and vi breast meat drip loss, juiciness and flavour, respectively. A positive and very strong relationship (r2 =0.998) was observed between dietary lysine to energy ratio and pack cell volume. Experiment 8 diets were formulated to have higher dietary lysine to energy ratios than the other experiments. Results of this experiment indicated that all the production parameters were influenced (P<0.05) by dietary lysine to energy ratio except mortality. Feed intake, growth rate, feed conversion ratio, live weight, apparent metabolisable energy and nitrogen retention were optimized at dietary lysine to energy ratios of 0.996, 0.980, 0.991, 1.010, 0.957 and 0.993, respectively. Dietary lysine to energy ratios of 0.992, 0.974, 0.991, 0.992, 1.023, 0.981, 0.979 and 0.815 optimized carcass weight, dressing percentage, breast meat, drumstick, liver weights and breast meat tenderness, juiciness and flavour, respectively. There were variations in the optimal lysine to energy ratios for different parameters investigated. In a diet containing 8 g of lysine per kg DM, 11.13 MJ of ME/kg DM and 150 g of CP/kg DM, dietary lysine to energy ratios of 0.719 and 0.649 are recommended for optimal live weight of Venda chickens aged one to seven and eight to 13 weeks, respectively. In a diet containing 9 g of lysine per kg DM, 12.13 MJ of ME/kg DM and 180 g of CP/kg DM, dietary lysine to energy ratios of 0.742 and 0.712 are recommended for optimal live weight of Venda chickens aged one to seven and eight to 13 weeks, respectively. In a diet containing 11 g of lysine per kg DM, 12.51 MJ of ME/kg DM and 220 g of CP/kg DM, dietary lysine to energy ratios of 0.878 and 0.894 are recommended for optimal live weight of Venda chickens aged one to seven and eight to 13 weeks respectively. In a diet containing 12 g of lysine per kg DM, 12.05 MJ of ME/kg DM and 240 g of CP/kg DM, dietary lysine to energy ratios of 0.996 and 1.010 are recommended for optimal live weight of Venda chickens aged one to seven and eight to 13 weeks, respectively. The results obtained in this study showed that different production parameters of Venda chickens were optimized at different lysine to energy ratios. This implies that the nutritional requirements of these chickens are dynamic and thus, dietary lysine to energy for optimal production depends on the production parameter of interest. This has implications on ration formulation for indigenous chickens.

Beak trimming at two different ages, Week-1 and Week-8, under four dietary regimens, varying in percent crude protein (CP) and metabolizable energy (ME) were compared. The dietary regimens were conventional high energy (CHE), conventional medium energy (CME), conventional low energy (CLE) and step-up protein regimen (SUP). At 20 weeks of age, 192 birds from each beak-dietary treatment were housed in laying cages for 24 weeks of egg production. One-half of the birds were provided with high light intensity ranging from 20 to 70 lux and one-half with low intensity from 2.5 to 22 lux. Cumulative feed intake through 20 weeks of age for the CHE fed birds was significantly lower than that for the CLE fed birds but did not differ from that of the CME or the SUP fed birds. The feed intake of the CME and CLE groups did not differ from each other; however, both were significantly greater than that of the SUP fed birds. Birds reared on CME had the lowest protein consumption with no difference in protein consumption between CHE, CLE and SUP fed birds. Birds reared on the SUP regimen had the lowest ME intake followed by the CLE group with no significant difference between CHE and CME groups. By 20 weeks of age, there was no significant difference in body weight for CHE, CME and CLE birds with those on SUP being significantly lower than all other treatments. Livability for the 20-week growing phase did not differ among dietary treatments. The influence of age when beaks were trimmed (Week-1 or Week-8) on feed, protein, and energy intake, body weight or livability for the 20-week growing period did not differ between the two beak treatments. By 44 weeks of age, there were no significant body weight differences among any of the juvenile dietary treatments. Age at 50% production, hen-day and hen-housed egg production, egg weight, shell quality, feed per egg, livability and mortality due to prolapse per se did not differ significantly among juvenile dietary treatments for the six 28-day production period. Birds reared on SUP regimen laid a significantly higher number of pee-wee eggs (< 42.5 g) and a significantly lower number of extra-large eggs (63.8 - 70.8 g) than those fed the other diets. Age at beak trimming and level of light intensity did not influence any of the parameters evaluated during the laying period. / Master of Science

Thesis (M.Sc.) --University of Limpopo, 2009 / Two experiments were conducted to determine the effect of dietary ascorbic acid supplementation levels on productivity, carcass characteristics and mortality of Venda chickens. The first experiment determined the effect of dietary ascorbic acid supplementation levels on productivity and mortality rate of 175 unsexed Venda chickens between 1 and 6 weeks old. The second experiment determined the effect of dietary ascorbic acid supplementation levels on productivity, carcass characteristics and mortality rate of 140 female Venda chickens between 8 and 13 weeks old. A Completely Randomized Design was used in both experiments. The treatments ranged from 0 to 2000 mg of ascorbic acid per kg DM feed. A quadratic equation was used to determine levels of ascorbic acid supplementation for optimum feed intake, feed conversion ratio, growth rate, live weight and breast meat yield. Feed conversion ratio, growth rate and live weight were optimized at different levels of 1050, 1301 and 1500 mg of ascorbic acid per kg DM feed, respectively, during the starter phase. Similarly, feed conversion ratio, growth rate, live weight and breast meat yield were optimized at different levels of 1000, 1250, 1482 and 769 mg of ascorbic acid per kg DM feed, respectively, during the grower phase. Dietary feed intake in both phases was not optimized within the range of values of ascorbic acid supplementation used in this experiment. The results indicate that at each growth phase, different levels of ascorbic acid supplementation optimized feed conversion ratio, growth rate and live weight of Venda chickens. However, level of ascorbic acid supplementation for optimum breast meat yield was lower than those for feed conversion ratio, growth rate and live weight. These findings have implications on ration formulation for Venda chickens.

Thesis (MA. Agric. (Animal Production)) -- University of Limpopo, 2014 / This study determined the effect of carrot meal supplementation on productivity and carcass characteristics of Arbor acres broiler chickens aged one to six weeks. Experiment I determined the effect of carrot meal supplementation on productivity of Arbor acre broiler chicks aged one to 21 days. Two hundred unsexed Arbor acre broiler chickens were randomly assigned to five treatments with five replicates, each replicate having ten birds. A completely randomized design was used in the first experiment. The treatments were 0 (UA0), 20 (AU20), 50 (AU50), 75 (AU75) or 100 (AU100) g of carrot meal supplementation per kg DM feed. Quadratic equations were used to determine levels of carrot meal supplementation for optimal feed intake, metabolisable energy intake and nitrogen retention of Arbor acre broiler chickens aged one to 21 days. Linear equations were used to determine relationships between carrot meal supplementation and productivity variables. Dietary carrot meal supplementation had no (P>0.05) effect on growth rate, live weight and feed conversion ratio of unsexed Arbor acre broiler chickens aged one to 21 days. Carrot meal supplementation, however, improved (P<0.05) metabolisable energy intake and nitrogen retention of the chickens. Dietary metabolisable energy intake and nitrogen retention of the chickens were optimized at different carrot meal supplementation levels of 40.5 and 53.57 g/kg DM feed, respectively. No chicken deaths were recorded. Experiment II determined the effect of carrot meal supplementation on productivity and carcass characteristics of female Arbor acre broiler chickens aged 22 to 42 days. The chickens were randomly allocated to five treatments with five replicates, each having 10 birds, in a completely randomized design. The supplementation levels were 0 (FA0), 20 (FA20), 50 (FA50), 75 (FA75), or 100 (FA100) g of carrot meal per kg DM feed. Quadratic equations were used to determine levels of carrot meal supplementation for optimal feed intake, feed conversion ratio, live weight, metabolisable energy intake and nitrogen retention of broiler chickens aged 22 to 42 days. Linear equations were used to determine relationships between carrot meal supplementation and production variables. Dietary carrot meal supplementation had no (P>0.05) effect on growth rate, live weight and carcass parts of female Arbor acre broiler chickens aged 22 to 42 days. Carrot meal supplementation improved (P<0.05) feed intake, feed conversion ratio, metabolisable energy intake and nitrogen retention of Arbor acre broiler chickens aged vi 22 to 42 days. Dietary feed intake, feed conversion ratio, live weight, metabolisable energy intake and nitrogen retention were optimized at different dietary carrot meal supplementation levels of 52.8, 63.8, 38.0, 42.0 and 44.3 g/kg DM feed, respectively. Dietary carrot meal supplementation had no effect (P>0.05) on tenderness and flavour of female Arbor acre broiler meat. Broiler chickens on diets supplemented with 20, 50 or 100 g of carrot meal per kg DM feed produced meat with better (P<0.05) juiciness values than those of meat from chickens not supplemented with dietary carrot meal and those supplemented with 75 g/kg DM feed. There was a positive relationship between carrot meal supplementation and chicken meat juiciness. It is concluded that carrot meal supplementation improved (P<0.05) metabolisable energy intake and nitrogen retention of unsexed Arbor acre broiler chickens aged one to 21 days. However, carrot meal supplementation had no effect (P>0.05) on growth rate, live weight and feed conversion ratio of unsexed Arbor acre broiler chickens aged one to 21 days. Carrot meal supplementation improved (P<0.05) intake, feed conversion ratio, metabolisable energy and nitrogen retention of female Arbor acre broiler chickens aged 22 to 42 days. However, carrot meal supplementation did not (P>0.05) improve growth rate and live weights of the chickens.

Thesis (MSc. Agriculture (Animal Production)) -- University of Limpopo, 2014 / Two experiments were conducted to determine the effect of moringa seed meal supplementation on productivity and carcass characteristics of Ross 308 broiler chickens. The first experiment determined the effect of moringa seed meal supplementation on productivity of Ross 308 broiler chickens aged one to 21 days. Two hundred and fifty unsexed day-old Ross 308 broiler chicks were randomly allocated to five dietary treatments, replicated five times, and each replication having 10 chickens. A completely randomized design was used. The chickens were fed on a grower diet supplemented with 0 (M0), 5 (M5), 10 (M10), 15 (M15) and 20 (M20) g of moringa seed meal/bird/day. Moringa seed meal supplementation had no effect (P>0.05) on feed intake, metabolisable energy intake, nitrogen retention, feed conversion ratio and live weight of unsexed Ross 308 broiler chickens. Moringa seed meal supplementation improved (P<0.05) growth rates of unsexed Ross 308 broiler chickens aged one to 21 days. A moringa seed meal supplementation level of 13.3 g/kg DM feed optimized growth rate of Ross 308 broiler chickens aged one to 21 days. The second experiment determined the effect of moringa seed meal supplementation on productivity and carcass characteristics of female Ross 308 broiler chickens aged 22 to 42 days. The chickens weighing 558 ± 10 g/bird were randomly allocated to five treatments with five replications having 10 birds. The chickens, aged 21 days, were allocated to the treatments in a completely randomized design. The chickens were fed on a grower diet supplemented with 0 (FM0), 5 (FM5), 10 (FM10), 15 (FM15) and 20 (FM20) g of moringa seed meal per kg DM. Moringa seed meal supplementation had no effect (P>0.05) on feed intake, growth rate, feed conversion ratio, live weight, metabolisable energy intake, carcass weight, breast meat weight, abdominal fat pad weight, liver weight, heart weight, thigh weight, meat flavour, juiciness and tenderness of female Ross 308 broiler chickens. However, moringa seed meal supplementation improved (P<0.05) nitrogen retention and gizzard weights of female Ross 308 broiler chickens. vi It was concluded that moringa seed meal supplementation improved growth rate of unsexed Ross 308 broiler chickens aged one to 21 days. Similarly, moringa seed meal supplementation increased nitrogen retention and gizzard weights of female Ross 308 broiler chickens aged 22 to 42 days.

Thesis (MSC. Agriculture (Animal Production)) --University of Limpopo, 2014 / Two experiments were conducted to determine the effect of moringa seed meal supplementation on productivity and carcass characteristics of Ross 308 broiler chickens. The first experiment determined the effect of moringa seed meal supplementation on productivity of Ross 308 broiler chickens aged one to 21 days. Two hundred and fifty unsexed day-old Ross 308 broiler chicks were randomly allocated to five dietary treatments, replicated five times, and each replication having 10 chickens. A completely randomized design was used. The chickens were fed on a grower diet supplemented with 0 (M0), 5 (M5), 10 (M10), 15 (M15) and 20 (M20) g of moringa seed meal/bird/day. Moringa seed meal supplementation had no effect (P>0.05) on feed intake, metabolisable energy intake, nitrogen retention, feed conversion ratio and live weight of unsexed Ross 308 broiler chickens. Moringa seed meal supplementation improved (P<0.05) growth rates of unsexed Ross 308 broiler chickens aged one to 21 days. A moringa seed meal supplementation level of 13.3 g/kg DM feed optimized growth rate of Ross 308 broiler chickens aged one to 21 days. The second experiment determined the effect of moringa seed meal supplementation on productivity and carcass characteristics of female Ross 308 broiler chickens aged 22 to 42 days. The chickens weighing 558 ± 10 g/bird were randomly allocated to five treatments with five replications having 10 birds. The chickens, aged 21 days, were allocated to the treatments in a completely randomized design. The chickens were fed on a grower diet supplemented with 0 (FM0), 5 (FM5), 10 (FM10), 15 (FM15) and 20 (FM20) g of moringa seed meal per kg DM. Moringa seed meal supplementation had no effect (P>0.05) on feed intake, growth rate, feed conversion ratio, live weight, metabolisable energy intake, carcass weight, breast meat weight, abdominal fat pad weight, liver weight, heart weight, thigh weight, meat flavour, juiciness and tenderness of female Ross 308 broiler chickens. However, moringa seed meal supplementation improved (P<0.05) nitrogen retention and gizzard weights of female Ross 308 broiler chickens. vi It was concluded that moringa seed meal supplementation improved growth rate of unsexed Ross 308 broiler chickens aged one to 21 days. Similarly, moringa seed meal supplementation increased nitrogen retention and gizzard weights of female Ross 308 broiler chickens aged 22 to 42 days.

Day old Dekalb XL-link pullets were randomly assigned to eight dietary treatments of 100 birds each. The percent crude protein (CP) with the respective weeks fed in parentheses for each treatment (T) was as follows: T1. control 18(0-6), 15(6-14) and 12(14-20); T2. 18(0-1), 12(1-8), 15(8-14) and 18(14-20); T3. 18(0-1), 12(1-10), 15(10-16) and 18(16-20); T4. 18(0-1), 12(1-12), 15(12-16) and 18(16-20); T5. 16(0-1), 12(1-10), 15(10-16) and 18 ( 16- 20 ); T6 . 16 ( 0-1 ) , 12 ( 1-12 ) , 15 ( 12 -16 ) and 18 ( 16- 2 0); T7. 20(0-1), 12(1-10), 15(10-16) and 18(16-20); and T8. 20(0-1), 12(1-12), 15(12-16) and 18(16-20). All diets were fed ad lib. The control pullets were heavier for most of the 20-week growing period. Skeletal growth was highly correlated with body weight, however body size was not different at 20 weeks. Cumulative feed intake of the control fed birds was significantly greater than five of the reverse protein fed birds. Feed conversion and protein intake suggested a potential economic advantage in reverse protein feeding. At 20 weeks of age, 576 pullets were transferred to laying cages and fed a common diet. No differences in body weight were seen at 28 weeks of age. Livability was not affected by dietary treatment. Hen-day and hen-housed figures showed significant treatment effects during the first 28-day period only. No significant differences were seen in egg weight, % egg size, egg mass, egg specific gravity, shell deformation, Haugh units or any feed trait. Reverse protein feeding appeared to offer promise as a method of restricting growth in egg-type pullets. The significance of effects on egg production traits may have been masked by small sample size. / M.S.

Thesis (M.Sc. (Animal Production)) --University of Limpopo, 2007 / Two experiments were conducted to evaluate the effect of time of initiation of feeding after hatching and influence of dietary lysine and ascorbic acid supplementation on productivity, carcass characteristics and mortality of Ross 308 broiler chickens. The first experiment examined the effect of time of initiation of feeding after hatching and influence of dietary lysine supplementation during realimentation on productivity, carcass characteristics and mortality of Ross 308 broiler chickens during the winter period. Three hundred and sixty unsexed Ross 308 broiler chickens with an initial weight of 30 ± 2 g per bird were assigned to twelve treatments with three replications of ten birds each in a 4 (times of initiation of feeding) x 3 (lysine supplemental levels) factorial, complete randomized design. At each time of initiation of feeding after hatching during the starter and grower stages, the diets were isocaloric and isonitrogenous but with three different lysine supplementation levels. Lysine supplementation started three days after hatching. Time of initiation of feeding above 36 hours after hatching resulted in growth retardation and high mortality rate. More than 50 % of the birds died between one and three days of age when initiation of feeding after hatching was above 36 hours. However, the birds ‘caught-up’ at the latest within eight days of realimentation. This compensatory growth could be explained in terms of higher intakes. Lysine supplementation during realimentation reduced the number of days of ‘catch-up’ irrespective of time of initiation of feeding after hatching. Generally, the higher the level of lysine supplementation, the lower was the number of days of ‘catch-up’ upon realimentation. Thereafter, time of initiation of feeding after hatching and lysine supplementation had no effect (P>0.05) on live weight, feed intake, growth rate, feed conversion ratio, diet digestibility, nitrogen content of breast meat, dressing %, carcass characteristics and mortality of Ross 308 broiler chickens. The second experiment examined the effect of time of initiation of feeding after hatching and influence of dietary ascorbic acid supplementation on productivity, carcass characteristics and mortality of Ross 308 broiler chickens during the summer period. Six v hundred and seventy five unsexed Ross 308 broiler chickens with an initial weight of 32 ± 2 g per bird were assigned to fifteen treatments with three replications of fifteen birds each in a 3 (times of initiation of feeding) x 5 (ascorbic acid supplemental levels) factorial, complete randomized design. Ascorbic acid supplementation started 3 days after hatching. An average of 18 % and 31 % of the birds died between one and three days of age when initiation of feeding after hatching was above 36 hours. However, the birds ‘caught-up’ within ten days of realimentation irrespective of time of initiation of feeding after hatching. This compensatory growth could be explained in terms of reduced maintenance requirement and possibly, increased efficiency of growth. Following ‘catch-up’, ascorbic acid supplementation during realimentation lowered (P<0.05) mortality rate and improved growth rates irrespective of time of initiation of feeding after hatching. Growth rate increased incrementally with increasing levels of ascorbic acid supplementation within each time of initiation of feeding after hatching. Improved growth rate in the ascorbic acid supplemented birds resulted in improved live weight in comparison with those without ascorbic acid supplementation at 21 days of age and continued until 42 days of age. Live weight increased incrementally with increasing levels of ascorbic acid supplementation within each time of initiation of feeding after hatching. Similarly, increasing ascorbic acid supplementation within each time of initiation of feeding after hatching increased dressing percentage and breast meat yield at 42 days old. However, ascorbic acid supplementation had no effect (P>0.05) on feed intake of the birds irrespective of time of initiation of feeding after hatching. In both experiments, mortality was positively and strongly correlated with time of initiation of feeding after hatching while live weight was negatively and strongly correlated with time of initiation of feeding after hatching. It is concluded that time of initiation of feeding above 36 hours after hatching is not desirable, mainly because of its effect on mortality. However, lysine supplementation in the diet of broiler chickens subjected to delayed initiation of feeding after hatching might play a key role in accelerating the rate of ‘catch-up’ growth response. vi It is also concluded that the beneficial effect of ascorbic acid supplementation could be exploited in reducing mortality rate and improving growth rates in broiler chickens subjected to delayed initiation of feeding after hatching. / the National Research Foundation

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.