Effect of strain, sex and age on carcass parameters of broilers

A total of 1,080 one-day-old broiler chicks were used, distributed into a completely randomized design in a 6 x 2 x 4 factorial scheme, with six replications of 30 birds each (15 males and 15 females). Chicks were classified into six breeds (Cobb 500 Slow, Cobb Fast, Ross 308, Ross 508, Hybro Plus and Avian 48), male or female and four slaughter ages (43, 45, 46 and 49 days). Ten birds from each experimental unit (5 males and 5 females) were slaughtered to evaluate carcass yield and commercial cuts. Cobb 500 Slow males showed the maximum potential for weight gain at 47 days old, while the other breeds, between 33 and 35 days old, regardless of sex. Carcass and breast fillet yield showed significant differences, independent of breed, sex and slaughter age, highlighting Cobb breeds. Significant interactions were observed for breast yield, boned and deboned legs among breeds, sex and slaughter age; sex was the determining factor. Wing yield has not been affected by any of the studied factors

Efeito da suplementação dietética de antioxidantes sobre características reprodutivas de machos reprodutores de frangos de corte na fase pós pico de produção

Because of their membrane constitution, sperm cells of male broiler breeders are prone to lipid peroxidation, which affects their fertilizing capacity. The aim of the present study was to evaluate the effects of antioxidant diet supplementation on the reproductive characteristics of 12 male broiler breeders (Cobb) older than 50 weeks. The roosters were randomly distributed in a completely randomized experimental design with two treatments (treatment 1: commercial feed; treatment 2: commercial feed supplemented with canthaxanthin, lycopene, and vitamin C) and 6 replicates. Semen samples were collected by abdominal massage, and then underwent evaluation of semen volume, sperm concentration, motility, vigor, and morphology. Morphometric analyses of testes, combs, and dewlaps were performed at 68 weeks. Testes samples were collected for morphometric analysis of seminiferous tubules and analysis of cellular proliferation in the germinal epithelium by using immunohistochemical staining with anti-proliferating cell nuclear antigen (anti-PCNA) antibodies. Statistical data analysis was performed using the SAS software (SAS, 2002). No significant effects of antioxidant supplementation were observed on semen characteristics (p > 0.05). A significant positive effect of the antioxidant blend was observed on the percentage of normal sperm, dewlap weight and width, and testes weight and length (p 0,05) com a adição dos antioxidantes sobre as características seminais. Houve efeito positivo (p < 0,05) do blend de antioxidantes no percentual de espermatozoides normais, no peso e largura das barbelas e no peso e comprimento dos testículos. A contagem de células PCNA-positivas e as medidas morfométrias dos túbulos seminíferos dos testículos dos galos não sofreram influência do tratamento. A adição de antioxidantes na dieta de machos reprodutores de frango de corte na fase póspico pode ser uma ferramenta nutricional para melhorar o índice de fertilidade dos lotes de matrizes de frangos de corte