Tibiotarsus bone characteristics and tibial dyschondroplasia incidence of broilers fed diets supplemented with leucine and valine.

Two experiments were conducted to study the effect of standardized ileal digestible (SID) leucine and valine levels on tibiotarsus bone characteristics and the incidence of tibial dyschondroplasia of broilers from day 1 to 21 (Experiment I) and day 21 to 42 post-hatch (Experiment II). Each experimental phase was evaluated independently. In both experiments, a total of 1,500 one-day-old Cobb 500 male broiler chickens were distributed in a completely randomized design 5 × 5 factorial arrangement for a total of 25 treatments. The SID leucine and valine levels were ranged from 10.0 to 19.6 g/kg, and 6.0 to 12.0 g/kg from day 1 to 21 post-hatch, respectively, while day 21 to 42 post-hatch ranged from 10.0 to 18.0 g leucine/kg, and 5.2 to 11.2 g valine/kg. Serum calcium and phosphorus, bone concentrations of calcium, phosphorus and ash, diameter and Seedor index of the tibiotarsus were not affected (p > .05) by the treatments at 21 or 42 days of age. There was an interaction (p ≤.06) between the SID levels of leucine and valine on tibiotarsus breaking strength at 21 days, but not at 42 days of age (p > .05). Tibiotarsus breaking strength was maximized in broilers from day 1 to 21 with the dietary levels of leucine and valine at 14.2 and 9.0 g/kg respectively. Dietary leucine levels reduced linearly (p < .05) the hypertrophic zone of tibiotarsus cartilage at 21 days of age. Therefore, leucine and valine supplementation interact positively on bone strength of broilers from day 1 to 21 post-hatch. Leucine can be a useful amino acid for reducing the hypertrophic cartilage zone in broilers from day 1 to 21, but not from day 21 to 42 post-hatch.

Relação vitamina E: vitamina C sobre a qualidade da carne de frangos submetidos ao estresse pré-abate / Vitamin E: vitamin C relationship on meat quality of broiler chicken submitted to pre-slaughter stress

Determinou-se a melhor relação vitamina E:vitamina C em dietas para frangos de corte, visando ao melhor desempenho produtivo e à melhor qualidade da carne das aves submetidas ao estresse pré-abate. Utilizaram-se 800 pintos de corte, machos, distribuídos em delineamento inteiramente ao acaso, em esquema fatorial 2x4, com dois níveis de suplementação de vitamina E - 0 e 250mg/kg - e quatro de vitamina C - 0, 150, 300 e 450mg/kg. Aos 42 dias de idade, 12 horas ante mortem, amostras de aves de cada tratamento foram submetidas ao estresse por calor e, em seguida, pelo transporte. Foram avaliadas características de desempenho - peso vivo, consumo de ração e conversão alimentar - , bem como rendimento de carcaça e qualidade da carne de peito e coxas - perda de água, cor e pH. Os níveis de vitaminas avaliadas não influenciaram nas características de desempenho avaliadas. Houve menor rendimento de peito (34,2 vs. 34,9%) e maior pH inicial (6,3 vs. 6,1) dos cortes, para aves que sofreram estresse em relação àquelas que não foram submetidas ao estresse pré-abate.

The best relationship for vitamin E:vitamin C in diets for broilers regarding growth performance and meat quality of birds submitted to pre-slaughter stress was determined. 800 male chicks at one day of age were distributed in a completely randomized design in a 2x4 factorial scheme, with two levels of vitamin E supplementation - 0 and 250mg/kg - and four of vitamin C - 0, 150, 300 and 450mg/kg. At 42 days of age, 12 hours ante-mortem, samples of birds from each treatment were submitted to heat stress and then transportation. The performance characteristics evaluated were body weight, feed intake and feed:gain ratio, carcass yield and meat quality of breast and thighs, water loss, color and pH. The levels of vitamins evaluated did not influence the performance characteristics measured. There was a lower breast yield (34.2 vs 34.9%) and higher initial pH (6.3 vs 6.1) in the cuts for birds that suffered stress than for those who did not undergo pre-slaughter stress.

Utilização da glutamina, associada ao ácido glutâmico, sobre o desenvolvimento e a atividade enzimática em frangos de corte / Utilization of glutamine, associated with glutamic acid, on development and enzymatic activity in broiler chickens

Avaliou-se o efeito da glutamina, associada ao ácido glutâmico, proveniente de um produto comercial, sobre o desenvolvimento e a atividade enzimática em frangos de corte. Foram utilizados 800 pintos de corte, machos, de um a 42 dias de idade, distribuídos em cinco tratamentos, sendo quatro níveis de suplementação do Aminogut®: 0,5; 1,5; 3,0 e 5,0 por cento + uma dieta-controle, isenta do produto. Observou-se melhor índice de eficiência produtiva para os frangos alimentados com dietas suplementadas com 2,8 por cento de Aminogut®. Independentemente dos tratamentos, verificou-se aumento das atividades da maltase, sacarase e fosfatase alcalina intestinais com o avanço da idade das aves. Para as enzimas pancreáticas, observou-se maior atividade da amilase e lipase aos 14 dias de idade, coincidindo com a maior taxa de crescimento alométrico do pâncreas.

Evaluation of the effect of glutamine associated with glutamic acid in a commercial product, on the growth and enzyme activities in broiler chickens. 800 day-old male broiler chicks were used during the 42 days of trial, and were allotted to five treatments, four levels of Aminogut® supplementation - 0.5, 1.5, 3.0 and 5.0 percent + control-diet, free product. The best index of productive efficiency in broiler chickens was observed in those fed diets supplemented with 2.8 percent Aminogut®. Regardless of the treatment, there was increase in maltase, sucrase and alkaline phosphatase activities as the age of the chickens increased. For pancreatic enzymes, more activity of amylase and lipase can be observed at 14 days of age, coinciding with the highest rate of allometric growth of pancreas.