Effects of exogenous melatonin on ovary activity during anestrus and reproductive seasons in ewes in Argentina.

CHAVES, M.A.; TERRANEO, M.B.; CERIONI, A.; VÁZQUEZ, M.I.

Simposio; Symposium of Animal Reproduction; 2015

This study investigated the effect of melatonin treatment and level of nutrition on follicular development and oocyte competence during anestrus. According to a 2x2 factorial design, 30 ewes were treated (MEL) or not with a melatonin implant. After 42 days, animals were synchronized with progestagen pessaries and fed to provide 1.5 (C) or 0.5 (L) times daily maintenance requirements. Follicular development was evaluated from Day -3 (oestrus=Day 0) to ovulation by ultrasonography. Ewes were mated and ovariectomized on Day 5. Healthy oocytes were matured, fertilized and incubated. Embryo development was evaluated throughout an 8-d culture period. No effects of diet or melatonin treatment were observed on growth rate of the ovulatory follicle but diet effect was significant on the mean diameter of the ovulatory follicle (C=45.5±1.7; L=40.2±1.9 mm; P