Abstract: This experiment was conducted to evaluate the effect of age on ovary function and oxidative stress in laying hens.48 Jinghong hens of 17 weeks of age were selected and fed with the basal diet until 36 and 48 weeks of age.24 Jinghong hens of 78 weeks of age fed with the basal diets until 97 weeks of age. The results showed as follows: compared with the young hens,numbers of hierarchical yellow follicles,small yellow follicles,primary follicles and secondary follicles were decreased significantly (P<0.05),whereas the follicular atresia rate of smaller yellow follicles,large white follicles and secondary follicles were increased significantly (P<0.05).The content of LH and progesterone in serum were decreased as age growing, but there were no significant differences at 36, 48 and 97 weeks of age (P>0.05).The content of SOD and GSH-Px in liver and ovarian were significantly decreased as age growing (P<0.05),whereas the content of MAD increased significantly (P<0.05).These results indicated that ovary function decline might be related with oxidative stress of liver,ovary and serum.

Key words: weeks of age; laying hens; ovary function; oxidative stress; follicular atresia