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Abdominal fat. Marshall broilers. Cost benefit. Feed:gain ratio. PALABRAS CLAVE ADICIONALESGrasa abdominal. Broilers Marshall. Coste/beneficio. Conversión alimenticia. SUMMARYTwo hundred and sixteen unsexed 14 daysold Marshall broiler chicks were used in a 3×3 factorial experimental design to test the effect of restricting feed intake of birds by 0 %, 20 % and 40 % levels for 2, 4 and 6 weeks after two weeks of the starter phase. The unrestricted (control) treatments were fed ad libitum throughout the experiment. The experiment lasted for 42 days. Data were collected and calculated on weight gain, feed:gain, feed intake, mortality, proximate composition of meat and cost-benefit analysis. Data obtained were subjected to a 2-way analysis of variance. Results showed significantly higher (p<0.05) final weights in the unrestricted birds (control) compared to the restricted birds. Interaction between duration of restriction and level of restriction indicated that weight gain and feed intake significantly (p<0.05) reduced as duration and level of feed restriction increased. Feed:gain was significantly (p<0.05) different across the treatments with birds restricted at 40 % for 6 weeks having the best feed:gain (1.91). The mortality recorded was not significant (p>0.05) across duration and level of restriction. Abdominal fat decreased with increasing duration and level of restriction with birds on 40 % level and 6 weeks duration of restriction having the lowest fat content (0.20 %). Crude protein content of the breast muscle significantly increased while crude fat content of the breast muscle significantly decreased with duration and level of restriction. Crude fat content was lowest at 40 % level and 6 weeks duration of feed restriction. As level and duration of feed restriction increased, feed cost/ kg reduced. Birds restricted at 40 % level for 2, 4 and 6 weeks durations respectively had better cost benefit than birds restricted at 0 and 20 % levels for 2, 4 and 6 weeks durations. It can be concluded that the best feed:gain, lower abdominal fat, higher protein and better cost benefit was achieved in birds restricted at 40 % for 6 weeks. RESUMENDurante 42 días, 216 pollos broiler Marshall, de 14 días, fueron empleados en un diseño experimental factorial 3x3 para estudiar el efecto de la restricción de la ingestión de alimento en 0, 20 y 40 %, durante 2, 4 y 6 semanas en la fase de iniciación. El tratamiento control (no restringido) recibió alimentación ad libitum durante todo el experimento. Se obtuvieron datos sobre ganancia de peso, alimento/peso, ingestión, mortalidad, composición de la carne y relación coste beneficio. Los datos obtenidos se sometieron a un análisis de varianza de dos vías. Los resultados mostraron mayor peso final (p<0,05), en las aves sin restricción, la interacción duración*nivel de restricción indicó que tanto la ganancia de peso como la ingestión, se redujeron cuando aumentaron la duración y nivel de restricción. La relación alimento/ganancia fue diferente (p<0,05) entre tratamientos siendo la ...

This trial was carried out to determine the responses of two broiler strains of chicken to different post-hatch access to feed. 180-day old chicks (Arbor acre and Marshal strains) with initial weight range of 39.36–42.24 g were used for this study. Each strain was divided on weight equalization into three treatment groups consisting of three time-periods with access to feeds (4 h, 24 h, 48 h) post hatch in a 2 × 3 factorial experiment after which they were fed ad-libitum. Thirty (30) birds were assigned to each treatment which comprised of three replicates of ten birds. Data collected on serum biochemical constituents and gut morphology were measured and subjected to analysis of variance in a randomized design. The Marshal strain recorded a higher (p < 0.05) final live weight (2420.00 g/bird) than the Arbor acre strain (2218.30 g/bird). Birds fed at 4 h and 24 h post-hatch recorded higher (p < 0.05) final live weights (2402.00 and 2391.00 g/bird) than those fed at 48 h post-hatch (2133.00 g/bird). Interaction effects showed that the Marshal strain fed at 4 h post-hatch had the highest (p < 0.05) final live weight (2594.00 g/bird). Highest (p < 0.05) serum total protein and albumin (37.3 and 22.8 g/l) were recorded in birds fed at 4 h post-hatch when assessed at 4 weeks of age. Furthermore, birds fed at 4 h and 24 h post-hatch recorded higher (p < 0.05) serum total protein and albumin than those fed at 48 h post-hatch. Birds fed at 4 h post-hatch recorded the highest (p < 0.05) duodenal villus height at 4th and 8th week of age and highest (P < 0.05) jejunal villus height when assessed in the 2nd week of age. It was concluded that Marshal strain fed at 4 h post-hatch elicited the highest growth performance and the most developed gut morphological features.

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