Comparison of Blood Serum Biochemical Compositions and Ovarian Follicular Fluid of Different-Sized Follicles in Dairy Cows

Biochemical compositions of ovarian follicular fluid may be influenced by blood serum metabolic changes and metabolic function of follicular cells. This study was performed to investigate some metabolic and hormonal changes of blood sera and ovarian follicular fluid of different-sized follicles in dairy cows. Follicular fluid from three groups of differentsized follicles; small (< 5 mm), medium (5-10 mm) and large (> 10 mm) in diameter were extracted, separately. Tail vein blood samples were obtained from 10 cows before slaughtering. Concentrations of hormones including IGF-1, estrogen, progesterone and concentrations of metabolites such as glucose, urea, cholesterol and triglyceride of blood sera and follicular fluid were determined using related commercial kits. For comparison metabolites and hormones concentration in blood sera and follicular fluid the linear mixed model, was used. This study showed a significant increase in glucose, estrogen and IGF- 1concentrations of follicular fluid by increasing of follicular size, but a significant decrease in urea, triglyceride and progesterone concentrations by increasing of follicular size. In addition, this study indicated a significant partial correlation for IGF-1(r=0.48), progesterone (r=0.47), urea (r=0.76) and cholesterol (r=0.74) concentrations between blood sera and follicular fluid. The results of this study showed that, biochemical compositions of follicular fluid is influenced by biochemical compositions of blood sera. Moreover, This study revealed a clear relationship between the follicular fluid concentrations of stradiolhormones, IGF-1, glucose, urea, cholesterol and triglyceride with follicle growth. Overall, the identification of essential biochemical compounds for growth and maturation of follicles, provides background to the requirement for enhancing the oocyte growth and ultimately to provide optimal reproduction.