Call number: LD2668 .T4 1985 Z58 / Master of Science

Assignment (MPhil)--University of Stellenbosch, 2002. / ENGLISH ABSTRACT: The study conducted was aiming on evaluating the influence of different levels of energy and amino acids, mainly lysine and methionine, on production performance of the layer bird. There were three treatments, namely the Control diet, a high energy, lysine and methionine diet (High spec.) and a low energy, lysine and methionine diet (Low spec.). The energy levels were 11.2 MJ/kg, 11.5 MJ/kg and 10.9 MJ/kg respectively. Lysine levels were 0.67%, 0.73% and 0.63% whereas methionine levels were 0.36%, 0.38% and 0.34% respectively. The experimental design was 3 x 4 factorial, which is 3 treatments with 4 replicates each. Results showed no significant difference (P>0.05) between treatments in egg production, egg mass, egg output, bodyweight and mortality. Feed intakes of the High spec. diet were significantly lower (P<0.05) than that of the control diet and the Low spec. diet. / AFRIKAANSE OPSOMMING: Hierdie studiestuk handeloor die evaluering van die invloed wat die verskillende vlakke van die energie en aminosure, veraiiisien en methionine op die produksie van 'n lê hoender het. Daar was gebruik gemaak van drie behandelings, naamlik die kontrole dieet, 'n hoë energie, lisien en methionien dieet (Hoë spesifikasie), en 'n lae energie, lisien en methionien dieet (Lae spesifikasie). Die energievlakke was 11.2 MJ/kg, 11.5 MJ/kg en 10.9 MJ/kg onderskeidelik. Lisienvlakke was 0.67%, 0.73% en 0.63% waarby methionienvlakke was 0.36%, 0.38% and 0.34% onderskeidelik. Die eksperimentele ontwerp was 3 x 4 fakulteitsfunksies: 3 behandelings met 4 replikas elk. Die resultate het geen noemenswaardige verskille (P>0.05) tussen die behandelinge in eierproduksie, eiergewig, eier-uitset, liggaamsgewig en mortaliteite nie. Die voerinnames van die hoë spesifikasie dieet was aansienlik laer (P<0.05) as die van die kontrole en lae spesifikasie dieet.

Four experiments were carried out with laying hens to evaluate the effects of body weight, age, dietary protein, and tallow levels on performance, nutrient intake and energy utilization. In the first experiment, Single Comb White Leghorn birds were divided into four body weight groups at the onset of egg production. Voluntary feed intake was 18% less for the lightest (1.39 kg) in comparison with the heaviest group (1.83 kg). Egg weight was directly related to body weight with the heavy birds producing an average egg weighing 65.3 g and the lightest birds having an average egg weight of 58.9 g. Feed conversion was also significantly better for the lighter birds. Maintenance requirements for the heaviest and lightest birds were 60.5 and 57.9% of metabolizable energy consumed, respectively. Metabolizable energy intakes above maintenance were 131 kcal/d for the heavy birds and only 119 kcal for the light group. A composite regression analysis indicated a maintenance requirement of 127.7 kcal/d/kg('0(.)75) and an energetic efficiency of 75.2% for the conversion of metabolizable energy to net energy. In order to evaluate the effects of age and body weight on laying hen performance, the last three experiments were designed using old, molted, and young hens which were divided into the heaviest and lightest body weight groups. The old birds were 72 weeks old, the molted birds were 106 weeks old, and the young birds were 27 weeks old at the start of the studies. In each experiment the birds were fed ten experimental diets with 12, 14, 16, 18, and 20% dietary protein in combination of 1 and 4% supplemental fat. Egg output was increased with the supplementation of tallow in only the young birds; while energy retentions were improved in the old and molted birds with fat feeding. Average energy retentions per kg physiological body weight were 58.8, 41.7, and 38.6 kcal for the young, molted, and old hens, respectively. The light-bodied birds showed 9% better gross energetic efficiencies than the heavy-bodied birds. Estimated daily protein intake requirements were 16.8, 13.3, and 12.8 g/d to support production levels of 84, 64, and 66% for the young, old, and molted birds, respectively.

No description available.

No description available.

Two experiments were carried out to evaluate the effects of Pearl Millet in combination with different levels of flaxseed and natural pigment (Oro Glo 15RTM) on quantity of n-3 fatty acids in eggs, laying performance and yolk pigmentation. In the first experiment, six different diet treatments were used for six weeks, with 24 hens per treatment (three birds per cage, eight cage replicates). Control diet was a corn-soybean meal diet, and diets containing 0, 2, 4, 8 or 12% ground flaxseed in which all the corn was replaced by pearl millet. In the second experiment, the diet treatments consisted of pearl millet and three inclusion levels of ground flaxseed (4%, 6% and 8%) and two levels (0.1% and 0.2%) of natural pigment in a factorial arrangement. The experiment lasted for twelve weeks, with 18 hens per treatment (three birds per cage, six cage replicates). In each of the experiments, all the diets were formulated to be isocaloric and isonitrogenous and to meet or exceed NRC requirements. Body weight of the birds and feed consumption were recorded at weekly (first experiment) and biweekly (second experiment) intervals. Number of eggs and egg mass produced were measured and recorded on a daily basis. At the end of each of the experiments, all the hens were euthanized to determine liver integrity. In both of the experiments, flock performance parameters were not different among treatments. In regard to egg traits, in the second experiment after 8 week of the start of the experiment, birds fed with diets containing 8% flaxseed produced significantly ( P &lt; 0.05) smaller eggs compared to hens fed 4% flaxseed. Yolk pigmentation was lower (P &lt; 0.05) for the eggs produced by hens fed diets containing pearl millet compared with those produced by feeding corn-based diet. However, 0.1% or 0.2% inclusion of the pigment both proved to be suitable to restore yolk pigmentation to marketable levels. No difference was observed among diets in regard to liver haemorrhage. Evaluation of FA profiles indicated that birds fed a diet containing PM as the sole grain source, and low levels of flaxseed (6%) can produce eggs with more than 350 mg/egg of n-3 FA, which is the lower standard to market eggs as "n-3 FA enriched". / Keywords: laying hens, pearl millet, flaxseed, natural pigment, flock performance, eggs, liver haemorrhage.

The objective of the study was to determine the effects of Aloe ferox inclusion in drinking water on growth performance, blood biochemistry, physico-chemical characteristics, fatty acid profile and oxidative stability of broiler meat. The importance of A. ferox as a medicinal plant and factors that influence its utilization by communal poultry farmers were also investigated by use of a questionnaire survey. The survey revealed that the majority of respondents (84.6%) faced health challenges in their chickens and many relied (96.2%) on A. ferox to treat diseases and control parasites. The study also revealed that the choice of medicine (traditional or conventional) was influenced (P<0.05) by level of education and income. In the second phase of the research, a total of 600 Ross 308 day-old broilers, were randomly put in 6 treatment groups with 4 replicates, each having 25 birds. Fresh aqueous A. ferox leaf juice (ALJ) was administered in drinking water at a dosage of 20ml/litre to T1, T2 and T3 from day one to day 35, day one to day 14 and day 15 to day 28, respectively. Birds in T4 and T5 (positive controls) were treated with terramycin at the recommended dosage of 14g/litre of drinking water from day one to day 6 and from day 15 to 20, respectively; and birds in T6 (negative control) received distilled water from day 1 to 35. Feed Intake (FI), average daily gain (ADG) and feed conversion ratio (FCR) were calculated for the 5 week trial. After slaughter, carcass characteristics particularly dressing percentage (DP) and relative organ weight (ROW) were calculated. Serum biochemistry was also determined. For meat quality, pH and color were recorded 45 minutes and 24 hours after slaughter from the breast muscle. Fatty acid profiling and oxidative stability were determined using meat samples from the breast and thigh muscles. The results for growth performance showed that thebirds which were given A. ferox for the first two weeks (T2) consumed significantly (P>0.05) more feed (189.4g) than those in the negative control (159.6g) at the beginning of the starter phase. Subsequently, their ADG recorded on day 7 (27.1g) and day 14 (43.1g) were significantly (P<0.05) higher than the negative control (22.8g and 36.2g, respectively). Significant treatment effects (P<0.05) for FCR were reported in the 4th week for the birds that received A. ferox throughout (T1: 3.5). Carcass characteristics were not significantly (P>0.05) affected by A. ferox inclusion in drinking water. The highest high density lipoprotein (HDL) values (2.78 mmol/L) were yielded in T2and T3 had the lowest values (0.61mmol/L) for low density lipoprotein (LDL). For physico-chemical properties, no significant effects (P>0.05) of treatment on pH, colour, cooking loss and tenderness were observed. However, the group treated with A.ferox throughout the production cycle, had the highest pH (6.2), lowest lightness (38.5), highest redness (4.1), highest tenderness (13.86N) and the lowest cooking loss (12.6%). Significant treatment effects (P<0.05) were observed on the composition of the PUFA eicosatrienoic acid (C20:3c8, 11, 14(n-6)) of the breast muscle which was significantly lower in the A. ferox treatment groups than the positive controls. For the thigh muscle, there were significant (P<0.05) treatment effects on composition of palmitoleic acid (C16:1c9) and g-linolenic acid (C18:3c6, 9, 12 (n-3)). No significant (P>0.05) effects were found on oxidative stability of both thigh and breast muscles. In conclusion, the wide use of A. ferox by communal chicken farmers showed its importance as a medicinal plant. Apart from it being an effective medicinal plant, A. ferox inclusion in drinking water results in improved FI, ADG, reduced in LDLC and better g-linolenic and palmitoleic acid composition in the meat.

M. S.

No description available.

Three experiments were conducted to study the nutritional value of poultry litter in ruminants and poultry. In the first experiment, eight yearling wethers were used in a series of three metabolism trials to study the utilization of the nitrogen in autoclaved peanut hull broiler litter containing 32.6% crude protein (dry matter basis). Poultry litter nitrogen replaced 25, 50 and 100% of the nitrogen of a purified diet containing isolated soybean protein as the nitrogen source. Apparent digestibility of crude protein in the rations decreased significantly at each increase of litter nitrogen level beyond 25%. However, the depression of crude protein digestibility at 50% litter nitrogen level was small. Digestibility of the litter nitrogen, calculated by difference, was 67 and 64%, respectively at 25 and 50% level of the nitrogen, which were not much lower than 71% when only soy protein was used. Nitrogen retention and percent utilization of absorbed nitrogen were significantly lower at the 100% litter-N level than when no litter was used. There were no consistent differences in the nitrogen fractions of the rumen fluid and blood plasma among the rations. In the second experiment, three digestion and metabolism trials were conducted with 10 yearling wethers to study the protein and energy utilization of autoclaved peanut hull and woodshaving broiler litters when each was incorporated in corn-hay natural ration at levels of 25 and 50 percent. Apparent digestibility of crude protein did not show any significant difference among the rations. Crude fiber digestibility of the litter rations was higher than that of the control ration. Dry matter, NFE and energy digestibility were lower (P<.01) for the litter rat:ons and decreased significantly when the litter level in the ration was increased from 25 to 50%. No significant difference was observed in nitrogen retention, due to kind or level of litter in the rations. Crude fiber digestibility, calculated by difference, was significantly depressed when the level of litter was increased from 25 to 50%. There were no other significant differences in digestibility between kind or level of litter. The apparent digestibility of crude protein was 71.7%. Digestible protein content (on dry matter basis) for peanut hull and wood shaving litter were 23 and 22%, respectively. The average TDN value for ooth kinds of litter was 60% (dry basis). Average digestible energy values (kcal./kg. on dry matter basis) were 2472 and 2407 respectively for peanut hull and wood shaving litter. The corresponding values for metabolizable energy were 2212 and 2150 kcal./kg. There was no significant difference in digestible protein, TDN, digestible energy, and metabolizable energy values due to kind or level of litter. The third experiment was conducted to study the value of different levels of processed peanut hull litter as a partial protein supplement in a practical type broiler ration. When 1/6 or 1/5 of the protein in the basal diet was replaced with litter crude protein by the inclusion of 13.9 or 16.7% litter in the diet, there was no significant difference in rate of gain, compared to the control. When 1/4 of protein in the basal diet was replaced by litter crude protein (20.8% litter in the diet), a significant growth depression resulted. Feed efficiency of the litter fed groups was significantly lower than that of groups on the basal diet. / Ph. D.