Morphological Characteristics of Ovarian Tissues and Follicular Fluid Metabolites of Female Lambs and Ewes in Subtropics

Background: Oocyte and follicular fluid recovery and evaluation are a crucial step in assisted reproductive technologies. The aims of the current study were to evaluate the ovarian tissues and their resulting oocytes and follicular fluid of Awassi female lambs and ewes in subtropics of Saudi Arabia. Methods: Thirty reproductive systems of female lambs in addition to forty reproductive systems of ewes of follicular and luteal phases were collected. The ovarian tissues were evaluated through ovarian follicle numbers, oocytes recovery in addition to determination of follicular fluid (FF) metabolites. The ovarian follicles were categorized into small ( less than 3 mm), medium (3-5 mm) and large follicles ( greater than 5 mm). The medium and large ovarian follicles were aspirated for FF collection and oocytes recovery. The FF concentrations of total protein (g/dl), urea (mg/dl), glucose (mg/dl), total cholesterol (mg/dl) and triglycerides (mg/dl) were determined. Result: The weight of reproductive system and ovary were increased of ewes compared to female lambs. The number of small follicles was not differed among groups whereas the numbers of medium and large follicles increase in ewes groups. The highest number of medium follicles was found in ewes of follicular phase compared to other groups. Although the percentage of oocyte recovery increased in ewes compared to female lambs, the oocytes quality was not differed among groups. The total protein values were high (P less than 0.05) in FF of ewes compared to that of female lambs. On the other, the values of urea and triglycerides were low (P less than 0.05) in FF of ewes compared to FF of female lambs. Moreover, the values of total protein, urea and triglycerides were comparable in FF of ewes during follicular or luteal phase. Additionally, there is slight increase of glucose and slight decrease of total cholesterol values in FF of ewes compared to FF of female lambs. In conclusion, follicles of ovarian tissues, oocyte recovery and quality and follicular fluid biochemistry of female lambs and ewes showed differences. The recovered oocytes and FF are available for assisted reproductive techniques.