Influence Of Oxidative Stress Induced By Repeated Ovulation On Ovary Functions Of Laying Hens

The reproductive performance in laying hens is known to deteriorate with age, but the mechanismis unclear. The study found that the wild birds, their annual egg production very little, but as long as10years in their life cycle, almost no decline in reproductive performance. So we suppose that aging hensovarian function decline may be related to ovulation volume. To verify this conjecture, we designed thefollowing three tests.1. Age-dependent alterations in the ovarian activity and oxidative stress of laying hens48Jinghong hens of17weeks of age were randomly divided into two groups and fed the basal dietuntil36and48weeks of age.24Jinghong hens of78weeks of age fed the basal diets until87weeks ofage. The result showed that, the number of hierarchical yellow follicles（P<0.05）is decreased incomparison to young hens, so as to the smaller yellow follicles(SYF)(P<0.05) and large whitefollicles(LWF)(P<0.05); as well as higer atresia rate of SYF (P<0.05) and LWF (P<0.05) andsecondary follicular (P<0.05). There is an tendency decreasing in LH content in serum (P=0.0751). TheSOD and GSH-Px in liver and ovarian were decreased week by week, as well as increased in MDAconcentrations and the expression of Tfam mRNA.2. Induction of laying hens mature follicle ovulation in vitro and ROS levels in the process ofovulation.Records the egg production time of the hens at egg production peak, the usual time between eggproduction is about24h, and the clutch is above30eggs. After15min of laying take out the ovarian andseparate the F1follicle, ovulation can be completed within2hours in culture medium. The resultshowed that, the level of ROS will rose up at the process of ovulation.3. The alterations in the ovarian activity and oxidative stress of laying hens with same age differentegg productions.48Jinghong hens of17-weeks-old were randomly divided into two groups, one group hens weremaintained under6h light:18h darkness until32-week-old, then recover to18h light:6h darkness Theresult showed that, the hens laying more eggs had the higer expression of Tfam mRNA in F1follicular(P<0.05), and the SOD(P<0.05)、GSH-Px(P<0.05) in liver and ovarian were decreased, as the result, theexpression of LHR mRNA(P<0.05)、 FSHR mRNA(P<0.05) in follicular were decreased, as well asLWF (P<0.05), secondary follicular (P<0.05). finally result of the higher atresia rate of SYF (P<0.05)and LWF (P<0.05) and secondary follicular (P<0.05).