Effects of Dietary Energy Levels and Lysine Levels on Performance and Carcass Characteristics in Arbor Acres Broilers

This study was conducted to evaluate the effects of dietary energy levels and lysine levels on performance and carcass characteristics of 42-d-old broilers and to determine the optimum level of energy and lysine of AA broiler. A total of 160 1 -d -old male broiler chicks were randomly assigned to five experimental dietary treatments in a 2 ×2 randomized block design and a control treatment with 32 replicates of one bird per replicate pen. Energy and lysine concentrations were lower (L) or higher (H) than those of NRC (1994) recommendations which comprised of four trial diets, respectively, varied by 0.418 MJ of ME/kg of diet and 0.1% ratio from 0 to 3 weeks of age and from 4 to 6 weeks of age, and according with NRC (1994) recommendations the moderate (M) presented the control group diet. Results showed that ①when the levels of dietary energy were increased from 12.97 MJ/kg to 13.81 MJ/kg, the body weight of broilers was increased by 12.67% and feed gain ratio was decreased by 7%; with a 20% increasing in the level of dietary lysine, the body weight was significantly increased by 12.38%(P 0.05) and feed coversion ratio was decreased by 3.84%. There was an obvious interaction effect on feed gain ratio (P 0.05). ②The carcass weight, eviscerated weight, breast weight, thigh weight, abdominal fat weight and abdominal fat yield were increased with the increase of dietary energy and lysine. When the levels of dietary lysine were increased by 20%, the carcass weight, eviscerated weight, breast muscle weigh and breast muscle yield were significantly improved by 12.33%, 12.62%, 28.53%, and 3.11%, respectively. There was an obvious interaction effect on abdominal fat weight (P 0.05). ③Birds got the optimum growth and carcass performance when the levels of dietary energy were 13.81 MJ/kg , the levels of dietary lysine were 1.2% from 0 to 3 weeks of age and were 1.1% from 4 to 6 weeks of age. The profits of birds in HH was more 1.44 yuan/ bird than that of present NRC (1994) group.