Immune effects of Alarelin on ovarian development and GnRH receptor mRNA expression levels of pituitary in tilapia ( Oreochromis niloticus )

摘要

The effects of a gonadotropin releasing hormone analogue (GnRH-a, alarelin) on ovarian development and the associated gene expression in the tilapia (Oreochromis niloticus) pituitary gland were investigated for 60 days. Eighty sexually mature female tilapia were randomly divided into group I (GI, 10 μg alarelin), group II (GII, 15 μg alarelin), group III (GIII, 20 μg alarelin), and control group (GC). Anti-GnRH antibody levels peaked on day 30 in GI, days 40–50 in GII, and day 40 in GIII, and were highest in GII (P0.05). The highest follicle stimulating hormone β (FSH-β) and luteinizing hormone β (LH-β) concentrations occurred in GII and GIII on day 40, and were higher in GII than in the other groups (P0.05). No significant differences in FSH-β or LH-β concentrations were observed between GI and CG. FSH-β and GnRH receptor mRNA levels declined significantly in the pituitary after alarelin treatment, whereas LH-β mRNA increased by day 60. Alarelin treatment promoted ovarian and follicular development, which has implications for novel GnRH-based techniques established to regulate sexual maturation in tilapia.