Effects Of Grape Seed Extract On AA Broilers Under Oxidative Stress And Its Mechanism

The purpose of this study was to investigate the effects of grape seed extract（GSE）,onion peel extract（OPE）and rosemary extract（ROE）on growth performance and antioxidant capacity of broilers under oxidative stress,and to explore the regulatory role and mechanism of GSE on antioxidant function of broilers,so as to provide theoretical basis for the rational use of GSE in broiler production.Experiment 1 Effects of GSE,OPE and ROE on growth performance and antioxidant capacity of cocks under oxidative stressA single factor design was used in the experiment.200 1-day-old healthy roosters were randomly divided into 5 groups,with 40 chickens in each group.Each Rooster had one replicate,with a total of 40 replicates.PC group was fed with basal diet and intraperitoneal injection of normal saline for 7 days;NC group was fed with basal diet and injected with diquat intraperitoneally for 7 days;In GSE group,100 mg·kg^-1GSE was added to the basal diet and diquat was injected intraperitoneally（7 days）;In the ope group,100 mg·kg^-1OPE was added to the basal diet and diquat was injected intraperitoneally（7 days）;In the ROE group,100 mg·kg^-1ROE was added to the basal diet and diquat was injected intraperi-toneally（7 days）.The experimental period was 21 days.The results showed that:1)comp-ared with PC group,the growth performance of NC group decreased,the activities of AST and ALT in serum increased significantly（P<0.05）,the concentrations of ALB,GLB and TP decreased significantly（P<0.05）,the activities of SOD and GST in serum decreased significantly（P<0.01）,the activities of GST and T-AOC in liver decreased significantly（P<0.05）,and the activities of MDA in serum and liver increased significantly（P<0.01）.2)Compared with NC group,GSE group,OPE group and ROE group had higher growth performance,significantly lower serum ALT activity（P<0.01）,significantly higher serum SOD activity,and significantly lower MDA content in serum and liver tissue（P<0.01）.The activities of SOD,GST and T-AOC were significantly increased in GSE group（P<0.05）.Conclusion:the oxidative stress model is established successfully.GSE,OPE and ROE can improve the growth performance and antioxidant capacity of cocks under oxidative stress,and GSE has the best effect.Experiment 2 Effect of GSE on growth performance and antioxidant signaling pathway of AA Broilers under oxidative stress504 one day old healthy AA broilers were randomly divided into 7 groups with 6 replicates in each group and 12 broilers in each replicate.The PC group was fed with the diet supplem-ented with fresh oil and 25 mg·kg^-1VE;HNC group was fed with diet supplemented with oxidized oil and 50 mg·kg^-1VE;Group LNC,group I,group II,group III and group IV were fed with oxidized oil+25 mg·kg^-1VE and 0 mg·kg^-1、100 mg·kg^-1、200 mg·kg^-1、300mg·kg^-1、400 mg·kg^-1GSE.The experimental period was 42 days.The results showed that:1)compared with LNC group,the average feed intake and average daily gain of 22-42 days,whole period HNC group,group I,group II,group III and group IV were significantly increased（P<0.01）.Compared with the LNC group,the serum AST,ALT,GGT and TBIL concentrations in HNC group,group I and group II were significantly increased（P<0.01）,the activities of SOD,CAT and GSH-Px in serum and liver were significantly increased（P<0.05）,the activity of T-AOC was significantly increased（P<0.01）,and the content of MDA was significantly decreased（P<0.01）.2)m RNA expression in liver:compared with LNC group,Nrf2 in HNC group was significantly increased（P<0.05）,SOD1 and CAT in HNC group,group I and group II were significantly increased（P<0.05）,HO-1 in group I and group II was significantly higher than that in LNC group（P<0.05）.3)There was no significant difference in growth performance among PC group,HNC group,I group,II group,III group and IV group（P>0.05）.There was no significant difference in AST,ALT,GGT,TBIL concentration,SOD,CAT,GSH-Px activity and MDA content among HNC group,I group and II Group（P>0.05）.There was no significant difference in the activities of SOD,CAT and GSH-Px among HNC group,I group and II Group（P>0.05）.The m RNA expression levels of SOD1,CAT and HO-1 in liver tissues were not significantly different（P>0.05）.Conclusion:GSE can activate Keap1-Nrf2/ARE signaling pathway,promote the expression of antioxidant enzymes,improve antioxidant capacity,reduce oxidative damage and improve production performance.100 mg·kg^-1GSE was the best and could replace 25mg·kg^-1VE.In conclusion,diquat can reduce growth performance,antioxidant enzyme activity and damage liver function of roosters,and the model is established successfully.GSE,OPE and ROE can improve production performance,alleviate liver damage and improve antioxidant capacity of cocks.GSE is the best.GSE stimulates Keap1-Nrf2/ARE signaling pathway,promotes the expression of antioxidant enzymes,enhances antioxidant function and improves growth performance of AA broilers.Adding 100 mg·kg^-1GSE had the best effect and could replace 25 mg·kg^-1VE.