Abstract：How to maintain egg production persistency for broiler was the most critical problem in poultry industry. Oxidative stress was known to cause ovarian function decline in female chicken．The relationship between oxidative stress and reproductive performance in late laying period was still unknown．Six individuals at their laying age of 15 weeks and 22 weeks were randomly selected for the determination of 6 antioxidant index, including catalase (CAT), superoxide dismutase (SOD), nitric oxide synthase (NOS), nitric oxide (NO), malondialdehyde (MDA) and glutathione peroxidase (GSH-Px) among serum, liver and ovarian tissues. Our results showed that there were no significant differences in ovarian index and the number of prehierarchical follicles (big white follicles and small yellow follicles) between hens at 15 weeks and 22 weeks of laying age. SOD, CAT, NO and GSH-Px in serum and liver tissue of breeders were significantly decreased with the increase of laying week (P<0.05 or P<0.01). GSH-Px, and CAT in liver of breeders at 15 weeks of laying were significantly higher than those at 22 weeks of laying (P<0.05), while MDA and NOS were significantly lower than that at 22 weeks of laying (P<0.05). There were no significant differences in the 6 antioxidant indexes of ovarian tissue. Compared with the hens at 22 weeks of laying age, the concentration of both Gonadotrophin Releasing Hormone (GnRH) and Estradiol (E2) in serum were significantly higher at 15 weeks of laying age（P<0.05 or P<0.01). The Correlation anaylsis showed that there were significant positive correlation beween serum GnRH concentration and 3 antioxidant indexes (SOD, CAT and NO), between serum E2 concentration and 2 antioxidant indexes (CAT and NO). Our results indicated that the accumulation and aggravation of oxidative damage in serum and liver seems to relate to the decline of productive performance after laying peak.
2021, Vol. 34 
