Reproductive performance and transcriptome analysis of ovaries at different parities in female rabbits.

The pregnancy data of 658 female rabbits from the first to sixth parities (P1 to P6) under the same mating pattern were used to assess the rate of conception at different parities. The reproductive performance and follicular development of P1, P2, and P6 female rabbits were analyzed. The results showed that conception rate was dramatically reduced in P6. Compared with P1 and P2, P6 rabbits showed evidence of lower fertility in terms of total litter size, live litter size, survival rate at birth, and weights of kits at 3 and 5-wk-old. The primordial follicle storage at P6 was significantly reduced, with greater numbers of atretic follicles compared with P1 and P2. In terms of serum glutathione, reactive oxygen species, malondialdehyde, and ovarian Klotho protein, telomeres, the anti-oxidant capacity and ovarian function at P6 was significantly affected by parity. Further, based on the ovarian transcriptomes at P2 and P6, several genes related to reproductive regulation were identified. These findings provide a basis for improving the reproductive rate of female rabbits.