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

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, 3.5 y. old, 7/8 Sannen-Alpine] were randomly assigned to: a) Betacarotene group [BC, n = 10; 45.9 ± 1.97 kg live weight (LW), 3.04 ± 0.08 units, body condition score (BCS), supplemented with 50 mg of BC goat day−1], and b) Control group [CONT, n = 12; 46.2 ± 2.04 kg 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 ± 1.0 ng mL−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 ± 28.9 ng mL−1 p > 0.05) nor GH-PULSE (1.4 ± 0.5 pulses 6 h−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.