Effects Of Taurine On Growth Performance And Biochemical Index In AA Broilers

The experiment was conducted to study the effects of different levels taurine added in corn-soybean diet without fish meal on growth performance,immune and antixidant function,hormone metabolism and three major nutrients（sugar,protein and lipide）in AA broilers（1-21days）.And the experiment was to determine the optimum addition and period of taurine.A total of 180 1-day-old AA broilers were randomly allotted to 6 treatments.Each treatment contained 6 replicates with 6 broilers per replicate.Taurine levels were 0,0.05%,0.1%,0.15%and0.20%in each treatment diet respectively.In the experiment,the broilers weight and surplus feed were weighted once a week to calculate daily gain,daily intake feed and feed gain ratio.When test to 5 days and 21 days,6 broilers with weight close were randomly selected in each treatment to collect fasting blood and slaughter,and then to take out the liver and immune organs including spleen,bursa and thymus.The results showed that ttaurine levels had effect on daily gain and feed gain ratio.Adding taurine 0.1%,0.15%at 1⁵ days old and add taurine 0.1%at 6²1 days old could significantly increased daily gain,while decreased feed gain ratio.With the tautine levels increasing,daily gain firstly rose and then reduced,but feed gain ratio had the opposite tendency.It showed that too high or too low taurine levels could not made broilers exert the best performance.The results of antioxidant indicators showed that taurine levels in diet had significantly effect on the activities of GSH-Px,SOD,T-AOC and MDA in serum and liver（P<0.05）.With taurine levels increasing,the activity of GSH-Px,SOD and T-AOC was firstly increased and subsequently decreased,but MDA had the opposite tendency.At 1⁵ days old adding raurine 0.1%and 0.15%,the result was better.At 6²1 days old adding raurine 0.1%,the result was the best.The results of immune test showed that,the concentration of immunoglobulin（A,G,M）and IL-2 was significantly affected with taurine levels increasing（P<0.05）.The concentration was higher when adding taurine 0.1%and 0.15%at 1⁵days old,and the concentration was the highest when adding taurine 0.1%at 6²1 days old.At 5 days old.Thymus index of taurine 0.1%and0.15%groups were higher than the other group,but the other group had no significant difference.Spleen index and bursa index were significantly higher than the control group（P<0.05）.At 21 days old when adding taurine 0.1%,thymus index and spleen index were significantly affected（P<0.05）,but bursa index was not significantly affected（P>0.05）,while it was the highest.The results of hormone in serum test showed that at 5 days old and 21 days old,with taurine levels increasing the concentration of T₃,T₄ and GH had rising trend,while Cort had decreasing tendency.At 5 days old,the concentration of T₃,T₄,GH and IL-2 in taurine 0.1%and0.15%groups was significantly higher than the control group（P<0.05）,while the concentration of Cort was significantly lower than the control group.At 21 days old wihen adding taurine 0.1%,the concentration of T₃,IL-2 and GH was significantly increased（P<0.05）,while the concentration of Cort and T₄ in each group was not significantly affected（P>0.05）.Metabolism of the three nutrients showed that the concentration of GLU,TG and TP was reduced,while the concentration of serum protein was increased in varying degrees by adding different taurine levels in broiler diet.At 5 days old when adding taurine 0.15%,the concentration of GLU was significantly lowed,while the concentration of HDL was significantly increased（P<0.05）.And when adding taurine 0.1%and 0.15%,the concentration of TG and TC was significantly lowed（P<0.05）,while the concentration of serum TP,ALB was significantly increased and BUN was significantly decreased（P<0.05）.At 21 days old when adding taurine 0.10%,the concentration of GLU,TG and TC was significantly lowed（P<0.05）,while the concentration of TP was significantly increased（P<0.05）.Comprehensive analysis of growth performance,immune and antixidant function,hormone metabolism and three major nutrients metabolic change,broiler diets need to add taurine,and the resualt was the best when adding taurine 0.1⁰.15%at 1⁵ days old and adding taurine 0.1%at6²1 days old...