Endocrine Characterization of the Reproductive Axis in Highly Prolific Lacaune Sheep Homozygous for the FecLL Mutation

A prolific allele named FecLL is known to segregate in the meat breed of the French Lacaune sheep on the basis of ovulation rate record. To gain more knowledge about the physiological effects of FecLL, ewes homozygous for FecLL (L/L) were compared to wild-type ewes (+/+) for ovarian phenotype and reproductive endocrine profiles. At the ovarian level, the increased ovulation rate in L/L ewes was associated with an increased number of antral follicles of greater than 3 mm and with preovulatory follicles being, on average, 1 mm smaller. Intrafollicular estradiol and testosterone concentrations were not significantly different between the two genotypes. In contrast, L/L large follicles (≥6 mm) had lower intrafollicular progesterone concentration. At the molecular level, expressions of ovarian markers, such as CYP19A1, CYP11A1, CYP17A1, LHR, and INHA, were not significantly different between the two genotypes. In contrast, FSHR and STAR mRNA levels increased in granulosa cells from L/L ewes. Plasma concentrati...