In vitro development of ovine preantral follicles and oocyte cleavage rate are not affected by long-term ingestion of detoxified castor meal

In the present study, we evaluated the effect of long-term ingestion of detoxified castor meal on in vitro development of sheep preantral follicles as well as on the developmental competence of oocytes from antral follicles. Ovarian fragments were cultured for one or seven days and further analyzed by histology and fluorescence microscopy (experiment 1). The cumulus oocyte complexes (COCs) obtained from antral follicles were matured in vitro and activated by parthenogenesis or fertilization in vitro (experiment 2). Even after 1 day of culture, in both tested groups, a significant reduction in the percentage of primordial follicles and a concomitant increase in the percentage of intermediate follicles were observed when compared to non cultured tissue. After 7 days of culture, the percentage of primary follicles in both tested groups was significantly higher when compared to the non cultured tissue or the tissue cultured for 1 day (P < 0.05). The number of in vitro embryos produced was similar between the tested groups. However, for those animals fed with detoxified castor meal, the parthenogenesis method resulted in a higher number of embryos (morulae) when compared to in vitro fertilization (IVF) activation. In conclusion, detoxified castor meal can be used as an alternative protein source without affecting the ovine preantral and antral folliculogenesis.