Effect of ovarian morphology on in vitro oocyte recovery and quality, and certain follicular fluid steroids hormones concentrations in ewes

ABSTRACT

The present study was conducted to investigate the effects of ovarian morphology on oocyte quantity and quality, as well as on follicular fluid steroid hormones concentrations. Fifty pairs of ovaries were collected from Barbari ewes and grouped into right, left, CL bearing and non-CL bearing ovaries. The weight, length, width and thickness of the right, left, CL bearing and non-CL bearing ovaries were recorded. The follicles were classified according to their diameter into 3 groups; small [<2mm], medium [2-4mm] and large [>4mm] follicles. Oocytes were classified according to their morphology into 3 grades; COCS [Compact cumulus oocyte complexes], POCS [Partially invested with less than three layers of cumulus cells] and DO [denuded oocyte]. The concentrations of progesterone and estradiol 17 beta in the follicular fluid were estimated. Results indicated that, dimensions of both right and left ovaries were not significantly differed. However, the ovarian dimensions as well as their weights were significantly [P < 0.05] affected by the presence of CL, being higher in the CL bearing ovary. The average number of large follicles were significantly [P < 0.05] increased in the right ovary when compared to the left one. The recovered COCs number was found to be significantly higher [P < 0.05] in the right than left ovaries. A greater number of vesicular follicles and aspirated COCS were found in the non-CL bearing ovary than in the CL bearing ovary. The non CL bearing ovaries provide larger numbers as well as higher quality of COCs when compared to CL bearing ovaries and that the former can be used to collect good quality COCs for in vitro production of sheep embryos. The progesterone concentration of follicular fluid was significantly higher in CL- and non-CL bearing ovaries [27.75 and 12.33 ng/ml; P < 0.05, respectively]. Non-CL bearing ovaries had significantly [P < 0.05] higher concentration of estradiol 17beta than those found in CL bearing ovaries [22.10 vs.8.43 pg/ml, respectively]. It can be concluded that non-CL bearing ovaries provide a higher number as well as superior quality of COCs than those obtained from ovaries bearing CL suggesting that the ovaries without CL can be used to collect good quality of COCs in view of in vitro production of sheep embryos [IVP]