Glucogenic Precursor Release from Dietary Supply Is a Potential Amplifier of Monosodium-Glutamate Ovary Stimuli in Sheep with Low Involving Key Gene Mediators of the Glutamate Pathway

This study aimed to evaluate the effect of combined supplementation of MSG with glycerin, a glucogenic precursor, on ovarian function in sheep. Twenty-four ewes had estrus and follicular waves synchronized using three prostaglandin injections at 7-day intervals. The ewes were grouped: baseline TMR diet (Control; <i>n</i> = 8); glutamate diet (MSG; <i>n</i> = 8), receiving MSG (1 g/kg of body weight/day) for 16 days; and MSG plus glycerin (MSGLY; <i>n</i> = 8), which received MSG plus 150 mL of glycerin during the eight days prior to ovulation induction. MSG showed lower dry matter intake, while the MSGLY group showed increased heart and respiratory rates and skin temperature. Rectal temperature was higher in MSG and MSGLY. MSGLY also showed reduced triglyceride and urea levels. MSG and MSGLY exhibited decreased cholesterol and creatinine. MSGLY exhibited a higher number of large follicles and greater intraovarian blood perfusion after ovulation induction and larger corpus luteum perfusion. Ovulation rate increased by 64% in the supplemented groups vs. control. MSG supplementation led to greater SCL1A1, GRIA1, and GLUD1 genes expression. Thus, the combined supplementation of MSG and glycerin effectively enhances ovarian function in sheep, representing a viable nutritional strategy to improve reproductive outcomes.