Factors affecting in vitro maturation, yield and quality of camel (Camelus dromedarius) oocytes

The present work was conducted to study the effect of different culture media, adding of gonadotropins and maturation times on IVM rate of camel oocytes. Moreover, the effect of seasonal variations and ovarian status (presence or absence of corpus luteum) on yield and quality of oocytes was also investigated. Camel ovaries were collected during breeding and non – breeding seasons. The cumulus-oocytes complexes (COCs) were recovered and cultured either in TCM-199, Ham's F-10 or RPMI-1460. These media supplemented with or without gonadotropin hormones (GHs). The GHs were in form PMSG + hCG. The culture periods consisted of three times, 28,32 and 42h. The maturation processes were performed at 39°C under 5% CO₂ and 95% humidity. The results showed that the use of TCM-199 in culturing of camel oocytes led to a significant increase (P<0.05 or P<0.01) of in vitro maturation rate comparing with other culture media. The supplementation of maturation media with PMSG + hCG resulted in significant improvement of meiotic maturation rate of camel oocytes than in hormone- free media. The proportions of camel oocytes reaching M II were significantly elevated (P<0.05 or P<0.01) after 42h of culture time than other maturation times (28 or 32h). Concerning the effect of seasonal variations and ovarian status on the yield quality of oocytes, the results showed that the average number (AN) of recovered oocytes per ovary as well as the proportions of high quality oocytes (COCs) were significantly elevated during winter and spring compared to those harvested during summer and autumn (6.71 and 5.57 vs. 2.95 and 4.26 for AN, respectively, or 4.16 and 3.04 vs. 1.18 and 2.17 for COCs, respectively). Moreover, the total oocytes recovered (TOR) per ovary and the proportion of COCs categories were more in ovaries without corpus luteum (CL) than those collected from ovaries with CL (5.39 for TOR and 3.04 for COCs vs. 4.36 for TOR and 2.23 for COCs respectively). In conclusion, the high maturation rate could be achieved when oocytes were matured in TCM–199 supplemented with gonadoropin hormones in form PMSG + hCG and using maturation time of 42h. Furthermore, the seasons of winter and spring as well as the using of ovaries without corpus luteum are favorable subjects for recovery of high quality of camel oocytes (COCs) which have a worthy competence to be matured in vitro.