Effect of ovary preservation period on recovery rate and categories of dromedary camel oocytes.

The aim of this study was to evaluate the effect of different periods of ovary preservation at 25-30 °C for 5, 6, 7, 9, 12 and 24 h on recovery rate and oocyte categories of dromedary camel oocytes. Camel ovaries were collected from El-Bassatein slaughterhouse, Cairo. The collected ovaries were placed immediately after slaughtering into thermos in saline solution (0.9% NaCl) supplemented with antibiotics (100 IU penicillin and 100 μg streptomycin/ml) at 25-30 °C and transported to the laboratory within 4-5 h. Ovaries were washed three times with warmed (30 °C) phosphate buffer solution (PBS) and one time with ethanol (70%). All visible follicles on the ovarian surface (2-8 mm in diameter) were counted. Oocytes were aspirated using a 20-gauge hypodermic needle. Oocyte yield was recorded and the number of oocytes/ovary was calculated. Oocytes were classified into five categories (compact, partial denuded, denuded, shrunken and cleaved oocytes). Results show that average number of follicles on each ovary was not significantly affected by preservation period, although tended to reduce only after 5 h of ovary preservation. However, this number was insignificantly reduced by increasing period of ovary preservation more than 5 up to 24 h. Average number of oocytes on each ovary was significantly (P < 0.05) reduced only between 5 and 6 h of ovary preservation. Average number of oocytes showed higher reduction rate between 5 and 6 h from 12.4 to 9.3/ovary as well as between 9 and 12 h. Oocyte recovery rate showed insignificant decrease from 88.1% at 5 h to 78.6% at 9 h of preservation. However, it showed significant (P < 0.05) reduction to 62.0% between 9 and 12 h, then insignificantly decreased to 58.6 at 24 h of preservation of the ovaries. Frequency distribution and recovery rate of each category was the highest for compact oocytes and the lowest for cleaved oocytes at all periods of preservation. Increasing preservation period significantly (P < 0.05) decreased frequency distribution of compact and cleaved oocytes, while increased frequency distribution of partial denuded, denude and shrunken oocytes. It might be concluded from the present results that the preservation of dromedary camel ovaries at 25-30 °C for 5-6 h was effective for maintaining the oocytes quality and recovery rate compared with the other preservation periods.