Effects Of γ-aminobutyric Acid And Astragalus Polysaccharide On Growth Performance, Immune Function Of Broilers

γ-aminobutyric acid is a new type of feed additives at present, added to the basic diets of livestock and poultry,it can improve animal feed intake and feed utilization. Astragalus polysaccharide is an important traditional Chinese medicine, which has been confirmed that it can improve growth performance ,enhance immune function and the ability of animals to resist disease,etc.on the basis of toxicity and growth-promoting experiments in mice , the effects of GABA on broilers'growth performance and immunity was studied by adding different dose levels of GABA to the broilers'basic diet,in different stages of the experiment, Experimental group′s serum antibody levels and T lymphocyte transition were determined,in order to evaluate effectiveness of GABA on promoting growth of Broiler ,at mean time,to explore the Mechanism of GABA.This study was mainly divided into four parts:(1)GABA in mice LD50 and the accumulation of toxic were Determined,in order to evaluate the security of GABA in mice.⑵on the basis of feeding basic diet, three dose levels of GABA were choosed to drench every day, the experiment lasted 35days, production performance was measured regularly, After the end of the experiment, the Mice's immune organ was weighted⑶To study the effects of GABAon the growth performance and immune function of broilers, 160 Sanhuang chicks were randomly divided into 4 groups with 5 replicates (8 chicks per replicate), relevant indicators of chicks were detected different times. the experiment lasted 42 days.⑷To study the effects of GABA and APS on the growth performance and immune function of broilers, 200 Sanhuang chicks were randomly divided into 5 groups with 5 replicates (8 chicks per replicate), Including compoundⅠ,Ⅱ,Ⅲand APS group and control group.the experiment lasted 42 days.at meantime, the corresponding immunity index and the blood biochemistry index. were detected.The results showed that⑴GABA's LD50 calculated for 15.55g/kg,it Confirmed that GABA is non-toxic material and security in diet.⑵the mice were fed with 0.5 mg / kg, 1mg/kg, 2mg/kg of GABA, The test discovered that weight gain in mice significant improved compared to control group in the experiment 28th, the 35 days(P <0.05), the whole term of total weight gain and Average daily weight gain were significantly improved (P <0.05), the experimental group is expected to reduce feed consumption but no significantly difference (P> 0.05), Rate of food to weight of 1mg/kg, 2mg/kg dose of GABA Lowered significantly, compared with the control group(P <0.05).⑶Added three dose levels of GABA experiments showed that the total weight gain and average daily gain of test groups were significantly higher than control group﹝P<0.05﹞, the rusults suggested the weight gain of broiler chickens are related to the amount of additives. Chicken's average daily feed consumption were no significant differences (P>0.05) compared with the control group, Rate of food to weight of GABAⅡ,Ⅲgroup higher than control group﹝P<0.05﹞. In addition, After the second immunization 7,14 th, the newcastle disease antibody titer of GABA test groups increased significantly ,compared with the control group, GABAⅠ,Ⅱtest group significantly improved (P<0.05), GABAⅢgroup (P<0.01).GABA experimental group had no significant promoting effect of peripheral blood T lymphocyte transformation. At the same time, GABA test group can significantly increase blood albumin, globulin and total protein content and lower ball / albumin ratio (G/A)⑷Added three dose levels of APS and GABA experiments showed that compound 3 group had distinct ability to increase total weight gain and average daily weight gain ( P < 0. 05) , besides lower the Feed weight ratio significantly ( P < 0. 05) ,.Compared with APS group, Compound 3 Group were better than APS Group( P < 0. 05).In addition, the newcastle disease antibody titer of trial groups were higher than control group in the 14th after first immunization ( P < 0. 05),and significant higher than control groups in the 7, 14 days after the second immunization( P < 0. 01), T lymphocyte transformation showed that Compound 3 Group and APS can effectively enhanced the function of cell mediated immunity in chickens of 4-week-old(P<0.05),but did not of 2, 6- week old(P>0.05), The experimental results indicated that GABA synergy with APS had a better role in promoting the immune performance of broiler chickens.