This study was conducted to investigate the effects of varying levels of dietary lysine and feed allocation, on the performance of female broiler breeders. In trial 1, 900 Cobb breeders from 26 to 45 weeks of age were used. The first four treatments had a fixed level of lysine throughout the experimental period, with 1200, 1070, 930 and 800 mg Lysine/bird/day and the last two treatments had their levels of lysine changed every two weeks, with treatment five started off with 1200 mg lysine/bird/day followed by a gradual decrease up to 975 mg lysine/bird/day at 45 week old, while treatment six started with the lowest level of lysine, 800 mg/bird/day and at 45 week old the intake was 1025 mg/bird/day. The rations provided 1900KJ ME/ day, the birds received 160 g of feed/day. Dietary lysine did not affect body weight, egg production, or egg composition. There were no significant differences in age at 50%, or peak production. Birds receiving 1070 and 1025 mg lysine/bird.day had a slightly, but not significantly, higher production in the current study. Birds receiving 1200 mg lysine/bird.day had the highest body weight and the lowest egg production. In trial 2, 900 broiler breeder hens were used. Protein intake and feed allocation were changed for each treatment at 26, 38 and 50 weeks and ending at 60 weeks. Birds on T1 were fed a constant CP content (145 g protein/kg) but a decreasing feed allocation (175 to 145 g/d). Those on T2 had a constant feed allocation (160 g/d) and a decreasing CP (166 to 124 g/kg) while those on T3 had varying levels of protein (166, 124 and 166 g/kg) and feed allocation (160, 160, 145 g/d). Mean cumulative protein intakes were 5.2, 5.3 and 4.8 kg/bird and mean energy intakes were 417, 412 and 402 MJ/bird for T1, T2 and T3 respectively. Body weights differed significantly at the end of the trial (P<0.05) with T2 showing the highest weight gain. However, egg production, egg weight and egg output were not affected by treatment. These breeders did not benefit from the additional protein and energy provided in the first and second periods by T1 and T2 (vs. T3), nor did they benefit from the additional energy provided in the final ten weeks of production by T2. / M.Sc.Agric. University of KwaZulu-Natal, Pietermaritzburg 2013.

This study was conducted to examine the potential of plastic slats as flooring material for maintenance of broiler breeders. Although plastic slats are more expensive than wood slats, plastic slats are more durable and easier to clean. Wood and plastic slats were tested as full and partial flooring to determine the ideal proportion of slats for broiler breeder floors. Space allotment was 2040 cm²/bird on all floor treatments. . Arbor Acres broiler breeders, one of the more common strains in British Columbia, were raised to 58 weeks of age to monitor the influence of slat material and slat coverage on egg production and progeny growth over one production cycle. Since the pens were not set up to determine the number of eggs lost through slats, "egg production" values were actually egg recovery values. Over-all egg recovery was significantly higher on partial wood (PWS) and partial plastic slats (PPS) than on either of the full slat treatments. Breeders on full wood slats (FWS) had higher over-all egg production than those on full plastic slats (FPS). Differences were significant for three biweekly periods, but slats did not influence the over-all incidence of floor eggs and cracked floor eggs. The incidence of cracked nest eggs was significantly higher in FWS and FPS than in PWS and PPS pens during four lay periods and overall. The proportion of non-cracked nest eggs, which was taken as an approximation of the proportion of settable eggs, was higher for partial slat pens than full slat pens, and FWS pens had a higher proportion of non-cracked nest eggs than FPS pens. To monitor fertility and hatchability, eggs were incubated at 37, 42, 46, 50 and 56 weeks of breeder age. Fertility, hatchability of total eggs set and hatchability of fertile eggs was not affected by type of slats. Progeny from the hatch at 37, 46 and 56 week of breeder age were grown in Petersime battery cages to three weeks of age. The progeny of breeders on FPS had lower first week weight gain than the other progeny groups due to moisture loss when 7 FPS progeny were lost during the second growth trial. Weekly and over-all feed conversion of progeny was not affected by types of slats used by parents. The 56th week progeny were grown in Petersime battery cages to market age (six weeks). PWS and FPS progeny had higher third week weight gain than PPS progeny. During the sixth week, FWS and PWS progeny had higher weight gain than FPS and PPS progeny. The sixth week feed conversion of FPS progeny was higher than that of the other three progeny groups. No other differences were seen. As long as slats were used as partial flooring, there were no differences in egg production on wood or plastic slats. The proportion of "settable" eggs, fertility, and hatchability of eggs of plastic slat breeders were comparable with that of wood slat breeders regardless of slat coverage. There were significant differences in the 3-week growth of 37th, 46th and 56th week progeny and the 6-week growth of 56th week progeny on the different slat types, but the differences were not due to slat treatments. There was no interaction between breeder age and slat material, therefore the influence of slat material on egg production and progeny growth did not vary with breeder age. Although egg recovery and the number of settable eggs were lower for FPS breeders, breeders on plastic slats performed as well as those on wood slats in the present study. / Land and Food Systems, Faculty of / Graduate

The objective of the study was to evaluate the effect of an exogenous multi-blend enzyme ( -glucanase and xylanase) on the performance of the broiler chickens and laying hens fed diets based on wheat and barley. Experiments were conducted on a flock of broilers and two flocks of laying hens. In both cases feed and water were provided ad libitum. The enzyme effect of enzyme addition on the broiler performance involved 2080 day-old male and female chicks in 48 pens, allocated one of four dietary treatments (0, 50, 100 or 200g/ton enzyme supplementation), to 35 days of age. On day 35, ten birds from each treatment were sacrificed for the analysis of the digestive organs weight (gizzards and livers). The trial was divided into two phases: a starter (1 to 21 d) and grower (22 to 35 d). Feed consumption was measured weekly and birds were also weighed weekly. The investigation of enzyme effect in laying hen diets involved 896 birds for each specific period. Each replicate consisted of four cages (four birds per cage) with a common feeder; 16 hens/pen of 56 pens. Eggs were weighed three times a week, feed consumption weekly and birds every weeks. The addition of a multi-blend enzyme significantly improve body weight, body weight gain, food intake, and feed conversion ratio for both sexes (P<0.05) in broiler chickens. There was a significant improvement in egg production in laying hens (P<0.05). Egg weight and egg mass were not significantly improved. Wheat and barley have cell wall components (arabinoxylans and -glucans respectively) which have a negative effect on the nutritive value of these feeds and therefore performance in poultry fed diets based on these ingredients. Addition of an exogenous multi-blend enzyme( -glucanase and xylanase) could help reduce these effects and improve performance and digestibility values in poultry. The null hypothesis was there will be no difference between supplemented and un-supplemented diets based on wheat and barley in performance of poultry. The results of this study suggest that the inclusion of 50 g/ton enzyme helps improve poultry performance, especially in young birds. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.

The increased demand for breast meat of broiler chickens has challenged researchers to investigate management techniques that could be used to increase the production of this valuable commodity. Two experiments were conducted in this study; the first investigated the effect of early feeding of newly hatched broilers on breast meat yield (BMY) at market weight, and the second focused on improving BMY of broilers exposed to short daylengths by feeding higher than conventional levels of dietary protein. In the first experiment, of the 528 eggs set in the incubator, half were placed, at day 18, in hatching trays containing a commercial broiler starter feed whilst the others (the held group) were hatched conventionally. Six chicks from both fed and held groups were sampled at nine-hour intervals from the time that the first chicks hatched for a subsequent period of 36 h. After measuring their body weight these chicks were euthanised and dissected in order to measure their breast and yolk weights. Body protein, lipid and water contents were measured on each chick. At day 21, six birds from the fed and held groups were sampled, and body weight, breast weight and body protein content were measured. The yolk sac weight for fed birds was significantly reduced compared to that of held birds (P < 0.001). Both fed and held birds had the same breast weight at hatch, but at day 21 the mean breast weight of the fed birds was significantly heavier than of held birds (P < 0.05). The birds that were removed first from the hatcher had a reduced breast muscle weight compared to those that were removed last. In the second experiment, a total of 3200 day-old broiler chicks were reared in eight light-tight rooms. Four lighting regimens (12L: 12D, 16L: 8D, 20L: 4D and 24L: 0D) were randomised between rooms, with each light treatment being replicated twice. Each room was divided into four pens and 100 chicks in each pen received one of four dietary protein treatments. At day 35, three birds from each pen were sacrificed so that measurements could be made of breast, thigh, drum and wing weight, and carcass chemical composition. Breast weight increased as daylengths increased except in birds that were fed low protein diet (143 g protein/kg feed). High levels of dietary protein increased breast weight in birds on all other daylengths except for those on 12 h which showed a reduced breast muscle weight when dietary protein content was increased. The results of the first trial suggests that breast meat yield could be improved if newly hatched chicks are offered feed immediately after hatch, however the hypothesis that this increment was due to an overall increase in body protein content in the first few days after hatching could not be corroborated. The results further showed that held birds do not withdraw nutrients from breast muscle to maintain growth at hatch, this is because birds that stayed longer in the hatchery without feed showed increased breast muscle weight compared to those that were removed first. The second trial could not identify a suitable feeding programme to overcome the problem of a lower breast muscle weight that results from the use of 12 h of lighting compared to that when long daylengths are used. Highest breast weight was obtained when birds were fed high protein diet at 20 h. More research is required to further investigate the combined effect of early feeding and daylength on breast meat yield in broiler chickens. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.

The broad objective of the study was to determine the effects of restricted water intake on the growth, blood chemistry and meat quality characteristics of indigenous chickens in semi arid environments. A total of 15 flocks in communal villages and 12 flocks in resettlement schemes of Msinga District in South Africa were monitored for 30 months to determine the effects of production system and season on flock size, dynamics and constraints faced by indigenous chicken producers. As a follow up, 281 and 233 chicks hatched in November 2011 from 18 and 9 households in communal villages and resettlement schemes, respectively were monitored using a structured checklist to determine survival and causes of mortality from hatching up to 12 weeks of age. Kaplan-Meier survival distributions and the odds ratios for effects of potential risk factors were determined using survival analysis and logistic regression models, respectively. Flock composition and structure were significantly affected by production system and month. Farmers in resettlement schemes had approximately one cock and three hens more (P < 0.05) than those in communal villages. The number of growers and chicks were similar (P > 0.05) between the two production systems but chicks were the predominant age group (38 %) of each flock. The cock to hen ratio in households in communal villages was 1:3.5, while that in resettlement schemes was 1:3.7, suggesting that inbreeding might have been reducing flock productivity. Flock sizes in communal villages peaked in March (45.1 ± 3.02) during the post rainy season and declined steadily to a low of 34.7 ± 3.63 in September during the hot-dry season. The largest flock sizes in resettlement schemes were observed in January (52.4 ± 5.09) during the hot-wet season and the smallest in August (36.1 ± 5.98) during the cold- dry season. Households in communal villages had more chicks (P < 0.05) than cocks, hens and growers throughout the year except in June when the number of growers was equal to that of chicks. In resettlement schemes, the number of chicks was lower (P < 0.05) than the number of hens and growers, except in June and July when it was equal to that of growers. Total entries were not affected (P > 0.05) by production system. Hatched chicks were the major mode of entry, accounting for more than 97 % of entries into flocks. The contribution of purchases, gifts and exchanges was negligible. Mortality was the main cause of exits from flocks, accounting for 70 and 63 % of total exits among households in communal villages and resettlement schemes, respectively. The major causes of mortality were aerial predators, sub-optimalnutrition and inclement weather conditions, which were similar between production systems. The number of birds that exited flocks through slaughter for household consumption was higher (P < 0.05) among households in resettlement (34% of total exits) than communal villages (21 % of total exits). The proportion of chickens exiting flocks through sales was higher in communal (9 %) than resettlement (4.3 %) households. Chick survival from hatching to 12 weeks was higher (P < 0.05) in communal villages (55 ± 3.14 %) than in resettlement schemes (41 ± 4.19 %). Mean chick survival time did not differ (P > 0.05) between communal (56 ± 3.30 days) and resettlement (49 ± 3.23 days) flocks. Provision of water ad libitum and treatment of sick birds were important covariates in prolonging the survival time of chicks. The effects of restricted water intake on growth performance, blood chemistry, physicochemical properties, and sensory characteristics of meat from Naked Neck (NNK) and Ovambo (OVB) chickens were also assessed. In the experiment, 54 pullets of each strain with an average weight of 641± 10g per bird were randomly assigned to three water restriction levels for 60 days in a completely randomized design. The treatments were ad libitum, 70% of ad libitum and 40% of ad libitum water intake. Each treatment group was replicated three times. The pectoralis (breast) muscle was sampled for meat quality, fatty acid composition and sensory quality analyses. Ovambo chickens had superior body-weight at 16 weeks of age, average daily gains (ADG) and average daily water intake (ADWI) than NNK chickens. Body weight of birds at 16 weeks of age, ADG, average daily feed intake (ADFI), ADWI and water to feed ratio (WFR) declined progressively (P < 0.05) with increasing severity of water restriction, while food conversion ratio (FCR) values increased (P < 0.05) as the severity of water restriction increased. Naked Neck chickens had better FCR at the 40 % of ad libitum water intake level than OVB chickens. The dressing percentage per bird was higher (P<0.05) in water-restricted birds than those on ad libitum water consumption, irrespective of strain. Heart weight was significantly lower in birds on 40% of ad libitum water intake than those on ad libitum and 70% of ad libitum water intake, respectively. Packed cell volume was higher (P < 0.05) in NNK than OVB chickens offered waterad libitum, but similar in birds offered 70 and 40 % of ad libitum. There were no differences in erythrocyte count (RBC) and mean corpuscular volume (MCV) values between strains, but MCV was higher in birds on 40 than 70 % of ad libitum water intake, irrespective of strain. Naked neck chickens had higher (P < 0.05) white blood cell count (WBC) values than OVB chickens at 40 % restriction level, but lower WBC than OVB at 70 % water restriction level. Uric acid, creatinine, triacylglycerides, total cholesterol, low density lipid cholesterol, total protein and globulin increased (P < 0.05) with each increment in water restriction, but the increase in creatinine and total cholesterol was more pronounced in OVB than NNK chickens. The opposite was observed for uric acid. Alanine transaminase, alkaline phosphatase and aspartate transaminase activities were not influenced by strain and water restriction. It was concluded that the two strains could withstand up to 40 % of ad libitum water restriction, but NNK chickens tolerated water stress better than OVB chickens. Water intake levels of 40% of ad libitum produced meat with significantly lower (P < 0.05) cooking loss, and higher (P < 0.05) redness (a*) values in NNK chickens compared with OVB chickens. Water intake level had no effect (P > 0.05) on lightness (L*) and yellowness (b*) values, shear force, moisture and protein contents in both strains. The fat content of NNK meat was 41 % lower (P < 0.05) than that of OVB meat at 70 % of ad libitum, but 31 % higher at 40 % of ad libitum water intake. The ash content was significantly elevated (P < 0.05) in birds on 70 % of ad libitum compared to those on ad libitum and 40 % of ad libitum water intake, which had similar (P > 0.05) ash contents. Birds on 40 % of ad libitum water intake had significantly higher (P < 0.05) proportions of octadecanoic acid (C18:0), cis, cis-9,12-octadecadienoic acid (C18:2 ῳ-6), cis-8,11,14,17-eicosatetraenoic acid (C20:4 ῳ-6), cis-7,10,13,16-docosatetraenoic acid (C22:4 ῳ-6), cis-4,7,10,13,16,19-docosahexaenoic acid (C22:6 ῳ-3), total polyunsaturated fatty acid (PUFA), total omega-3 PUFA and total omega-6 PUFA proportions, but lower (P < 0.05) cis-7-hexadecenoic (C16:1c7), cis-9-octadecenoic (C18:1c9), cis-11-octadecenoic acid (C18:1c11), cis-13-docosenoic acid (C22:1c13), total monounsaturated fatty acids than those on the 70% of ad libitum and ad libitum water intake, respectively. The proportion of trans-9-octadenoic acid (C18:1t9) was higher (P < 0.05) in NNK chickens on 40 % of ad libitum water intake than OVB chickens. It was concluded that water restriction at 40 % of ad libitum water intake resulted in favourable cooking loss values and meat redness (a*) values, omega-3 and 6 PUFA proportions and a high ῳ-6/ῳ-3 ratio. The high fat content of NNK chickens at 40 % of ad libitum water intake compared to OVB chickens suggests a superior adaptation to hydric stress. Naked Neck breast meat had higher initial impression of juiciness scores than that from OVB chickens, but only in birds on ad libitum and 70 % of ad libitum water intake. Sensory scores for first bite, connective tissue and tenderness decreased with increasing severity of water restriction (P < 0.05). Aroma, flavour and atypical flavour were not affected by strain or water restriction level (P > 0.05). There were significant strain differences for sustained impression of juiciness and tenderness, with the highest scores occurring in NNK chickens (P < 0.05). Aroma had a significant influence on the flavour of breast meat (P < 0.05). Fat content was significantly correlated with initial impression of juiciness, first bite and sustained impression of juiciness of breast meat. It was concluded that water restriction up to 40 % of ad libitum had a significant and adverse impact on juiciness and first bite scores of meat. / Ph.D. University of KwaZulu-Natal, Pietermaritzburg 2013.