Effects Of Taurine On Growth Performance And Biochemical Indexes Of Caged Growing Laying Ducks

The experiment was conducted to study the effects of taurine on growth performance and biochemical indexes of caged growing laying ducks aged from5to10weeks.Using a single factor completely randomized design, a total of180five-week old Jinding egg-type ducklings were randomly assigned to5groups with6replicates per group, and each replicate contained6ducks. Ducks in control group (group Ⅰ) were fed a basal diet, and the others in experimental groups (groups Ⅱ-Ⅴ) were fed the basal diet supplemented with0.05%,0.10%,0.15%,0.2%taurine, respectively. The experiment lasted for6weeks.In the experiment,the laying ducks were weighted at the beginning and the end.For each replicate group, ducks weight and surplus feed were recorded weekly to calculate daily gain and feed conversion ratio. In the end,one was randomly taken out and taken blood from cervical part and randomly killed to take out the spleen、thymus index、bursa of fabricius for mensuration.The results of feeding experiment showed that supplementation of0.10%～0.15%taurine significantly improved average daily gain (P<0.05),and supplementation of0.10%taurine significantly reduced feed to gain (P<0.05), the average daily gain and feed to gain were changed quadratically with increasing dietary taurine level.The results of antioxidant capacity showed that supplementation of0.10%taurine significantly improved the serum and liver total anti-oxidation capability (T-AOC)(P<0.05), supplementation of0.10%～0.15%taurine significantly improved the serum and liver super oxide dismutase (SOD), the liver malondialdehyd (MDA) content, and serum glutathion peroxidase (GSH-PX) activity (P<0.05), but the liver GSH-PX activity and the serum MDA had no significant difference compared with the control group (P>0.05), and antioxidant capacity were changed quadratically with increasing dietary taurine level.The results of Hormone in serum test showed that supplementation of0.10%taurine significantly improved GH in serum (P＜0.05), and supplementation of0.15%taurine significantly improved InS in serum (P<0.05).Other biochemical indicators of blood test results showed that supplementation of0.1%significantly reduced glucose(GLU) and triglyceride (TG) content (P<0.05); supplementation of0.10%～0.15%taurine significantly reduced the content of total cholesterol(TC) and urea nitrogen(BUN)(P＜0.05).The results of blood sampling experiment showed that supplementation of0.10%～0.15%taurine significantly improved the content of IgG、IgM in the serum (P<0.05),the content of IgA in the serum had no significant difference compared with the control group (P>0.05). Supplementation of0.10%taurine significantly improved the bursa of Fabricius index and the spleen index, but the thymus index of Fabricius had no significant difference compared with the control group (P>0.05), the group adding with0.10%taurine, the thymus index of Fabricius achieved to the largest.Supplementation of0.15%significantly improved the content of albumin(ALB) and total protein(TP)(P<0.05).Supplementation of0.05%～0.20%taurine, the concentration of IL-2were increased, and adding with0.15%taurine,the concentration of IL-2is highest.These results combined with considering production performance, immunity, hormones related to metabolism and antioxidant functions indicated that basal diet supplemented with moderate level of taurine can improve growth performance, immunity, and antioxidant functions of egg-type ducklings. Based on the various indicators, the optimal taurine supplemental levels estimated by quadratic regression model analysis are0.103%to0.141%.