Desempenho e Comportamento de Frangos de Corte Alimentados com Dietas com Níveis Crescentes de Vitamina E.

Abstract

Two experiments were carried out to evaluate the performance, carcass characteristics and behavioral parameters of broilers fed different vitamin E levels. In experiment I and II, a total of 288 one-day-old male Cobb 500® broiler chicks were fed up to seven days old with 50% of vitamin E requirements. At eight days of age, the birds were homogenized and the treatments were distributed in a completely randomized experimental design, with four treatments and six replications, with 12 birds each. The treatments consisted of four levels of vitamin E (50%; 100%; 150% and 200%), as the 100% level corresponded to the right recommendation for each phase. The variables evaluated in experiment I were weight gain, feed intake, feed conversion, final weight at 21 and 42 days of age, viability, Productive Efficiency Index (PEI), carcass yields and noble cuts (thigh, drumstick and chest), and abdominal fat content. In the experiment II, they were evaluated the behavioral parameters of the birds (eating, drinking, investigating feather, comfort movement, scratching, standing and sitting), maximum, minimum and mean surface temperatures, thermal amplitude and feed intake within 24 hours at the end of each life cycle, at 21 and 42 days of age. There was no effect of vitamin E levels on performance variables at 42 days of age. Vitamin levels influenced the carcass yield, showing an increasing linear effect on this characteristic. It was observed at 21 old, vitamin E levels only influenced the frequency that the birds remained stationary, presenting lower frequency in the experimental treatment with 9.16 g vit / 100 kg of feed. However, the behavioral parameters (drinking, investigating feathers, comfort movement, scratching, standing and sitting), minimum and mean surface temperatures, and thermal amplitude were influenced by the morning, afternoon, night and dawn periods. Likewise, at 42 days of age, vitamin E levels did not influence behavioral parameters, which were influenced by the morning, afternoon, night and dawn periods. However, there was interaction between vitamin E levels in the drinking behavioral parameter. Feed intake in the period of 24 hours was not influenced by vitamin E levels at 21 and 42 days of age. The levels of 22.9 and 18.05 g vit/ 100 kg of feed, in the phases from 8 to 21 and from 21 to 42 days old, respectively, were sufficient to meet the requirements of broilers from 8 to 42 days old. Levels influenced the behavioral parameter of broiler chickens at 21 days of age, and the level of 91.60 mg/kg of feed is recommended for this phase.