Goats as Valuable Animal Model to Test the Targeted Glutamate Supplementation upon Antral Follicle Number, Ovulation Rate, and LH-Pulsatility

Simple Summary Exogenous glutamate administration to yearling-anestrous goats enhanced not only ovarian function (i.e., ovulation rate and antral follicle number) but also denoted undoubted effects at the hypothalamic-pituitary level, augmenting LH pulsatility. Our results show not only the use of glutamate as a clean alternative but also as an interesting reproductive strategy to amplify ovarian function, considering goats as an animal model. While this should enlarge the possibility of escalating our knowledge regarding the hypothalamic-pituitary-gonadal modulation by glutamate, such research outcomes may also embrace potential translational implications. The potential effect of intravenous administration of glutamate on the ovarian activity and the LH secretion pattern, considering the anestrous yearling goat as an animal model, were assessed. In late April, yearling goats (n = 20) were randomly assigned to either (1) Glutamate supplemented (GLUT; n = 10, Live Weight (LW) = 29.6 +/- 1.02 kg, Body Condition (BCS) = 3.4 +/- 0.2 units; i.v. supplemented with 7 mg GLUT kg(-1) LW) or (2) Non-supplemented (CONT; n = 10; LW = 29.2 +/- 1.07 kg, BCS = 3.5 +/- 0.2 units; i.v. saline). The oats were estrus-synchronized; blood sampling (6 h x 15 min) was carried out for LH quantification. Response variables included pulsatility (PULSE), time to first pulse (TTFP), amplitude (AMPL), nadir (NAD), and area under the curve (AUC) of LH. Ovaries were ultra-sonographically scanned to assess ovulation rate (OR), number of antral follicles (AF), and total ovarian activity (TOA = OR + AF). LH-PULSE was quantified with the Munro algorithm; significant treatment x time interactions were evaluated across time. The variables LW and BCS did not differ (p > 0.05) between the experimental groups. Nevertheless, OR (1.77 vs. 0.87 +/- 0.20 units), TOA (4.11 vs. 1.87 +/- 0.47 units) and LH-PULSE (5.0 vs. 2.2 pulses 6 h-1) favored (p < 0.05) to the GLUT group. Our results reveal that targeted glutamate supplementation, the main central nervous system neurotransmitter, arose as an interesting strategy to enhance the hypothalamic-hypophyseal-ovarian response considering the anestrous-yearling goat as an animal model, with thought-provoking while promising translational applications.