Study Of Green Tea Extracts On Growth Performance, Immunity And Antioxidative Effect Of Young Roosters For Egg Production

The young roosters for egg production were chosen as the model. Tea polyphenol andL-theanine extracted from the green tea were used to feed chicken and effect on the growthand immune function, blood biochemical indicator and antioxidant abilities through thefeeding experiment. Function of tea saponin and catechin on the anti-coccidiosis in vitro. Inorder for the scientific practice basis of green tea extracts in various application.The study be contained following three parts:Experiment1: The effects of L-theanine on growth and immune function, bloodbiochemical indicator and antioxidant abilities of young roosters for egg production.One-day old chicken (n=120) were randomly assigned to four groups for three replicates(10chicks for each).CK group was control group and fed on the basal diet. Group I–IIIwere the treatment groups and fed on the basal diet with an additive of L-theanine(100mg/kg,200mg/kg,300mg/kg).The growth performance,indexes of immune organs, bloodbiochemical indicator and antioxidant abilities of young roosters for egg production weredetermined.Experiment2: The effects of tea polyphenol and L-theanine on growthperformance, blood biochemical indicator and antioxidant abilities of young roostersfor egg production under heat stress. One-day old chicken (n=180) were randomlyassigned to six groups for three replicates (10chicks for each). Group I was control group,and fed on the basal diet. Group2–6were the treatment groups, and fed on the basal dietwith an additive of tea polyphenol or L-theanine. The henhouse’s temperature wascontrolled at35±3℃, The humidity was controlled in the70%or so. The growthperformance, index of immune organs,blood biochemical indicator and antioxidant abilitiesof young roosters for egg production were determined under heat stress.Experiment3: Study of function of tea saponin and catechin in vitr onanticoccidial. The suspension of un-sporulated Eimeria tenella was added into the Petridish at1mL/Petri dish, and tea saponin of15%,25%,35%,45%or catechin of20%,40%,50%,70%was added too. Taking1mL the K2Cr2O7solution as Control. Cultured at27℃.Oocyst sporation rate was counted in the24h,48h,72h and96h respectively. Addingequivalent volume of K2Cr2O7solution after eluting tea saponin and catechin,To countingthe oocyst sporation rate at day2and day4. The results showed that:(1) L-theanine had no significant effects on growth performance and immune functionunder300mg/kg. L-theanine could significantly effect on protein metabolism of youngroosters for egg production. The metabolism of protein synthesis was promoted,Theimmune function was enhanced. And the antioxidant capacity of the small intestine andliver was improved too. L-theanine could enhance the activity of CAT significantly(P<0.05),and could decrease the tissues and organs of MDA in different degree. The studyshowed that, The L-theanine could enhance the anti-heat stress ability of egg-layingchicken, and was a kind of safe feed additive. The appropriate addition amount was higherthan200mg/kg.(2) In certain concentration level of the tea polyphenol in diets could decrease Feed-weight ratio significantly (P<0.05),and could increase the spleen index (P<0.05), and coulddecrease the tissues and organs of MDA significantly (P<0.05),and could enhance theactivities of GSH-Px and CAT significantly (P<0.05).The tea polyphenosl and L-theaninewas added in diet simultaneously, The added amount of tea polyphenols and antioxidantproperties of poultry were not directly proportional relationship. Theaddition of teapolyphenols excess may produce anti nutritional factors effect, reduce antioxidantproperties.200mg/kg tea polyphenol added with200mg/kg L-theanine, the antioxidantfunction was relatively better.(3) Tea saponin and catechin had obviously inhibitory effects on sporulated form ofEimeria tenella coccidia in vitro, the more higher concentration of tea saponin and catechin,the more obvious inhibition effects. With the time of culture prolonged, the sporulated rateof Eimeria tenella coccidia in vitro decreased gradually.