Quercetin supplemented diet improves follicular development, oocyte quality, and reduces ovarian apoptosis in rabbits during summer heat stress

The present study was designed to test the modulatory effect of dietary quercetin on follicle population, apoptosis, in vitro maturation rate and quality of oocytes in heat stressed female rabbits. A total of thirtyfour New Zealand White heat stress (HS) exposed female rabbits were either fed with quercetin supplemented diet (QU-HS) or non-supplemented (HS) diet. Firstly, laparotomy was performed for oocyte retrieval and then, oocyte grading and COCs dimensional assessments were conducted. The A and B-grade oocytes were submitted for in vitro maturation. Thereafter, the ovaries were collected from rabbits and were processed for follicular population estimation and granulosa cells apoptosis. The results showed that follicle number, retrieved oocytes and A-grade oocytes were higher in QU-HS, comparatively. A significant difference was observed in A-grade oocytes dimensions between QU-HS and HS treatment groups. The oocyte maturation rate was same across the groups. The quercetin supplementation significantly improved primordial and antral stage follicles. A greater number of apoptotic cells were observed in primary and antral follicles in the HS group. In conclusion, the quercetin provision improves the follicular development, minimize granulosa cells 'apoptosis, and maintain the oocyte competence in HS rabbits. (C) 2017 Published by Elsevier Inc.