The key role of targeted betacarotene supplementation on endocrine and reproductive outcomes in goats: Follicular development, ovulation rate and the GH-IGF-1 axis

Abstract

The possible effects of betacarotene (BC) supplementation on the secretion pattern of growth hormone (GH) and insulin-like growth factor-1 (IGF-1), and their possible relationship with total ovarian activity (TOA), was evaluated in adult goats during the breeding season. In October, goats [n=22, 3.5y. old, 7/8 Sannen-Alpine] were randomly assigned to: a) Betacarotene group [BC, n=10; 45.9±1.97kg live weight (LW), 3.04±0.08 units, body condition score (BCS), supplemented with 50mg of BC goat day−1], and b) Control group [CONT, n=12; 46.2±2.04kg LW, 3.0±0.08 units, BCS]. An ultrasonographic scan was performed to evaluate corpus luteum number (OR) and antral follicle number (AF); TOA=OR+AF. Average LW and BCS did not differ (p>0.05) during the experimental period, yet BC-goats reflected an increased OR (3.4±0.2 vs. 2.8±0.2), AF (5.0±0.6 vs. 3.4±0.6) and TOA (8.4±0.5 vs. 6.2±0.6). Regarding the endocrine profile, the lowest (p<0.05) serum GH average concentrations (10.0 vs. 14.3±1.0ngmL−1; p=0.01) and GH-AUC (3670.4 vs. 5235.7±369.8 units; p=0.01), were observed in the BC-supplemented group. Neither serum IGF-1 concentrations (254.6±28.9ngmL−1 p>0.05) nor GH-PULSE (1.4±0.5 pulses 6h−1 p>0.05) differed between treatments. We document a potential role of BC as modulator of somatotrophic function, decreasing mean serum concentration and the area under the curve of GH, while also noting a positive action upon ovarian function with increases in ovulation rate and antral follicular development; such outcomes may embrace not only physiologic significance but also potential translational applications.