Effect Of Tea Polyphenols And Daidzein On Broilers Under Heat-Stress Conditions

Under high temperature, poultry can produce a large number of free radicals under heat stress. Though radicals has a very short time of half-life, it can react with DNA, protein and PUFA, which can make DNA chain rupture and damage, coupling of protein-protein, coupling of protein-DNA and fat anti-oxidation.Tea Polyphenols (TP) is a kind of active component of tea and a natural anti-oxidation, it can remove free radical, prevent the fat from peroxidation. The Daidzein (Da) of soybeans is a flavonoid plant estrogen. It has estrogen function which improves the reproduction performance of animal and can promote the growing of the animal muscles. In this experiment, the TP and Da were used together to alleviate the influences of heat stress in broiler. The results of feeding and anti-oxidant experiments can offer theoretical foundation on TP and Da under heat stress.A 3×2 factorial design was conducted to study the requirement of TP and Da for broilers. During 3~7 weeks., 162 broilers were assigned to nine groups randomly with three replicates of six chicks per replicate. Each group was fed with 0 mg/kg, 20 mg/kg, 30 mg/kg TP and 0 mg/kg,3mg/kg,6 mg/kg Da respectively. The experiment was carried out for 4 weeks including 1 week pre-experiment. The results of the experiment are as follows:The results of feeding experiment showed that TP could alleviate the effect of heat stress on performance of broilers. There were no significant different on feed intake, daily gain and feed conversion ratio of broilers (P>0.05). Da could decrease significantly feed conversion ratio of broilers (P<0.05) and had no significant effect on feed intake and daily gain (P>0.05), The interaction of TP and Da had no significant influence (P>0.05).TP could promote the level of T-AOC in the heart and liver under heart stress, and decrease the level of MDA in serum (P<0.05)but had no significant effect on the level of T-AOC in serum (P>0.05), the level of MDA in heart and liver, V_E. in heart Da had no significant effect on these anti-oxidant indexes (P>0.05), The interaction of TP and Da had no significant influence (P>0.05).There was no significant effect on blood sugar, blood cholesterol, total protein, white protein, CK and GOT by TP under heart stress (P>0.05). Da could decrease the level of blood cholesterol significantly (P<0.05), and had no significant effect on other serum indexes (P>0.05), The interaction of TP and Da had no significant influence (P>0.05).The results of immune experiment showed that there had no significant effect on immune organ indexes (P>0.05). Da could significantly improve thymus gland but had no significanteffect on spleen and bursa.F indexes. The interaction of TP and Da had extreme significant influence on thymus gland (PO.05), and had no significant effect on spleen and bursa.F indexes (P>0.05).TP could significantly decrease water dripping loss of muscle (PO.05), and had no significant effect on VE in the muscle and the rate of abdomen fat (P>0.05). Da had no significant effect on water dripping loss of muscle, Ve in the muscle and the rate of abdomen fat (P>0.05), The interaction of TP and Da had extreme significant effect (P>0.05)on above indexes.In general, TP and Da could improve the ability of anti-oxidation and performance of broilers under heat stress, The optimal level was 30mg/kg TP and 6mg/kg Da.