The Research Of Net Energy Requirement And Appropriate True Digestive Lys: Net Energy Ratio In 0-3 Week-old Yellow Broiler Chicks

Three experiments were designed in this study. The net energy and true digestive Lys was actually meatured in Experiment 1 and 2.Then the 3th Experiment was conducted to investigate the effects of true digestive Lys(TDLys)and Net Energy(NE) levels on growth performance and N balance in broilers to research net energy requirement and appropriate true digestive Lys:net energy ratio in 0-3 week-old Chinese color-feathered chicks.Experiment 1 The purpose of the study was to evaluate the net energy value of corn and soybean meal.58 8-d old male yellow broiler chicks were used to determin the retaine-d net energy by Comparative Slaughter. The length of the experimental period was from 8 to 15 days of,age, total 8 days. Another 20 chicks were used to determin the net energy requirement for maintenance for 0-3-weekend chicks.The NE of corn and soybean meal were 11.229 MJ/kg DM,7.041 MJ/kg DM.Experiment 2 To determin the true digestive Lys of corn and soybean meal for chicks,72 2-week-old male yellow broiler chicks were alloted randomly by weight to 3 treatments with 6 replicates per treatment. Broilers were offered protein-free diet freely to dermine the basal endogenous amino acid losses.The results were as follows:the true digestive Lys of corn and soybean were 0.266%,2.682%(DM).Experiment 3 360 1-day-old male yellow broiler chicks were randomly by weight assigned into 9 treatments, to assess dietary TDLys and NE for optimum growth performance and nitrogen metabolism. Broilers were fed three levels of Lys(0.89%,0.99%, 1.09%) and three levels of NE(8.268,8.686,9.104MJ/kg), respectively in a 3×3 factorial arrangement. The results were as follows:(1)Broilers fed on 8.686 MJ of NE/kg of diet exhibited greater(P<0.05 or P<0.01)ADG, greater nitrogen deposition and availability, and lower F/G ratio than those on a diet with 8.268 MJ of NE/kg; and there were no significant difference compared with the 9.104 MJ of NE/kg(P>0.05).The broilers fed on 8.686 MJ of NE/kg had the lower cost for ADG than that of the 9.104 MJ of NE/kg(P<0.01).(2) An obvious interaction effects of NE and TDLys on F/G ratio and nitrogen deposition was observed(P<0.05). There were no significant difference between the ADG, F/G and nitrogen depositon of MM and HH treatments (P>0.05), but the former had the best nitrogen avaliability and the lower cost for ADG.Considering the growth performance and nitrogen metabolism, the NE level of 8.686 MJ/kg and TDLys/NE level of 1.140 g/MJ were suitable for 0-3-week-old yellow broiler chiks.