Níveis de energia e nutrientes para frangos de corte : desempenho, rendimento de carcaça e expressão gênica

Abstract

The objective of this study was to evaluate the effects of energy levels and nutrient adjustments (lysine, calcium and phosphorus) on the performance, carcass yield and expression of genes related to the electron transport chain (ETC) in chicken liver cut from 22 to 42 days old. A total of 432 broiler chickens, male, Cobb 500 was distributed in a completely randomized design in three treatments with eight replicates eighteen birds each. The first treatment control (Ctrl), consisted of a feed based on corn and soybean meal containing metabolizable energy (EM) of 3025 kcal/kg. The second treatment (Ctrl+EM) were obtained increasing 150 kcal/kg in the amount of EM compared to control diet, keeping the values lysine, calcium (Ca) and phosphorus available (AP). In the third treatment (EM + CN), there was increase the value of EM (150 kcal/kg) compared to control diet and nutrients lysine, Ca and P were adjusted proportionally to the energy increase. The performance and yields of carcass parts of the birds were analyzed. Furthermore, the expressions of ND1 and COX1 gene were analyzed. The treatments provided significant effects on performance, which was not observed for yield of carcass parts. It was found that the increase in metabolizable energy of feed provided greater feed efficiency compared to control treatment. Compared with the control group, when it increased the energy and corrected the nutrients, improvement was observed in weight gain. The expression of genes of CTE (ND1 and COX1) did not differ between treatments. In conclusion, the results indicate that more energy rations and correction of nutrients promote improved performance of broilers (22-42d), but do not change the yield of carcass parts and the expression of genes of CTE.