Effect Of Dietary Green Tea Powder On The Growth And Immunity Of Broiler Chickens Infected By Coccidia

Green tea is known for its high enrichment of flavonoids and anti-bacterial components,which could promote immunity,antiseptic and other attack effects.The aim of this research was to investigate the effects of green tea as a poultry additive on broiler growth performance and immune response before and after coccidia challenge.The results could provide meaningful data on feed additive and antibiotic substitute selection in broiler.Four hundred AA male broilers were randomly allocated into 4 treatments consisting of 5 replicates with 10 birds in each replicate.Treatments were set in a 2(either Eimeria tenella challenged on d 14;or not)x 4(4 feed additives)factorial arrangement.The 4 feed additives included corn-soybean meal basal diet(control),basal diet with antibiotics;basal diet with probiotics,and basal diet with 1%green tea powder.At 42 and 49 days of age,five birds from each replicate were slaughtered for sampling.Slaughter performance was recorded,spleen and bursa of fabriciu’s were sampled for gene expression determination.The results were as below:On days 42,broilers from the control group exhibited greater body weight as compared to broilers fed green tea powder(P<0.05).The abdominal fat rate was higher in broilers fed probiotic as compared with broilers fed green tea powder or to broilers from control group(P<0.05).Birds challenged with coccidia exhibited a lower body weight(P<0.05)and carcass rate(P=0.015)at 42 d of age as compared with the none challenged group(table 2).At d 49,no significant feed conversion ratio(FCR)was detected among groups(P>0.05).Broilers with coccidia challenge showed a significantly higher gizzard weight as compared with broilers from none challenge group(P<0.05),while the ileum length and duodenum weight was significantly lower as compared with broilers from none challenge group(P<0.05).Broilers fed diet with AHES with lowest eggs detected,than from broilers fed diet with BS(P<0.05),and no significant difference from broilers fed diet with GTP(P>0.05).The oocysts number detected from birds fed diet with GTP or BS exhibited no difference(P>0.05).The expression level of IL-2 and IL-4 was determined by real-time quantitative PCR in spleen and bursa of fabricius of broilers.The results showed that the expression level of IL-2 in the spleen of broilers fed diet containing green tea powder was significantly higher than that of broilers fed a diet with probiotics(P<0.05).The expression level of IL-2 in bursa fabricius of broilers fed diet containing green tea powder was significantly higher than that of broilers fed a diet with antibiotics(P<0.05).The expression level of IL-2 was significantly higher in broilers fed a diet with green tea powder as compared with other groups after coccidea gavage(P<0.05).The expression of IL-4 from spleen was significantly higher in broilers from the control group as compared with other groups(P<0.05).The expression level of IL-4 was significantly higher in spleen and bursa fabricius of broilers fed a diet with green tea powder as compared with other groups after coccidea gavage(P<0.05).Green tea powder addition did not affect the body weight and meat production in broilers.However,green tea powder could reduce abdominal fat content and thus influence feed conversion ratio.Green tea powder addition could promote IL-2 expression level in spleen and bursa fabricius.In addition,green tea powder addition could also promote IL-4 expression level in broilers after coccidea infection.