The Performance, Nitrogen And Phosphorus Utilization Of Broilers Fed Phytase And Low CP Diets

Two studys were conducted, including the effects of low nitrogen diet and low phosphorus diet in AA broilers. It was expected to offer a detailed theoretical basis for the practial production on the trend of environmental protection.Trial 1:Effects of Phytase on Growth Performance, Nutrients Utilization and Tibia Ash in AA BroilersThis trial was aimed to investigate the effects of phytase on growth performance, utilization of nutrients, and tibia quality and biochemical parmeters on broilers.384 one-day-old AA chicks were randomly allocated to 6 treatments with 8 replicates of 8 chicks each. The feeding trial consisted of two periods (starter:1-21d, grower:22-42d). The corn-soybean meal-miscellaneous meal basal diets contained available phosphorus of 0.45% and 0.35% respectively were formulated as positive and negative control diets for broilers of starter period, and 0.4% and 0.3% respectively for broilers of grower period.250,500,1000 and 10000 FTU/kg of diet phytase were supplemented to the negative control diet resprctively as the experiment diets. The results showed that:dies supplemented phytase improved growth performance, nutrients utilization and phosphorus level in serum of broiler significantly compared with the nagtive dite. Addition of 250 U/kg of diet phytase to nagtive control diet maked up the decline of growth performance.250～1000 u/kg phytase supplement could deacreased the phosphorus emissions by 0.87～1.28 g every broiler in 42 days. However, the deficiency of phosphorus level needed supplementation of 500 U/kg of diet phytase to nagtive control diet.Trial 2:Effects of Dietary Nitrogen Levels on Growth Performance, Nutrients Utilization and Carass Traits in AA BroilersTo investigate the effects of dietary nitrgen levels on growth performance, utilization of nutrients, carass traits and in AA broilers, the present experiment was conducted. The control group was prepared with the standards of broiler nutrition (NY/T33-2004),21% CP level (1～10d),20% CP level (11～24d) and 19%(24-35d). The other two treatment groups were prepared by the same ME level with the control group, the CP level lower than the control group by 1 and 2%, respectively. At the same time, the synthetic amino acids were supplemented to meet the needs of EAA of broilers. Results showed that adding lysine, methionine and threonine to diet which reduced crude protein level was by 1% and 2%, no significant diffrernces in growth performance and slaughter performance (P>0.05). Compared with the control group, the experimental groups reduced the content of nitrogen in excreta of broilers. There was trend that crude protein gestibility of experimental groups was increased than that of the control group. The low CP dire could saved 19.59g nitrogen emissions in the whole period of every broiler. It was seemingly that profited more of reducing crude protein, because of the cheaper feed cost.