Effect of season on intrafollicular fatty acid concentrations and embryo production after in vitro fertilization and parthenogenic activation of prepubertal goat oocytes

Abstract

In this study we have assessed the concentration of 13 fatty acids (FAs) in follicular fluid (FF) and tested the blastocyst development of prepubertal goat oocytes after in vitro fertilization (IVF) and parthenogenic activation (PA) during spring, summer, autumn and winter. Ovaries were collected from a local slaughterhouse and transported to the laboratory during the four seasons. Samples of FF were recovered from follicles and FAs were analyzed by gas chromatography. Oocytes were in vitro matured in TCM-199 with hormones, epidermal growth factor and 10% of fetal bovine serum for 24 h. After maturation, oocytes were inseminated with fresh semen capacitated with heparin or parthenogenically activated with ionomycin and 6-dimetylaminopurine. Zygotes from both groups were cultured in SOF medium for 8 days. The results showed that the polyunsaturated FA (PUFA) concentration of n3 was significantly reduced in autumn compared to winter (46.17 μM and 116.45 μM, respectively) and the n6 to n3 (n6:n3) PUFA ratio was significantly higher in autumn than in winter (11.17 μM vs 4.23 μM, respectively). Blastocyst production was significantly higher (P < 0.05) in winter than autumn after IVF (16.8% and 5.5%, respectively) and showed a statistical tendency (P < 0.1) after PA (22.7% and 11.5%, respectively). In conclusion, in ovaries of prepubertal goats we have observed higher concentrations of n3 PUFAs and lower n6:n3 PUFA ratio in the follicular fluid and oocytes with higher competence to develop up to blastocyst in winter compared to autumn. Moreover, spring, which is a non-breeding season in goat, have not affected in vitro blastocyst production from suckling kid oocytes.