Influence of vitamin A injection before mating on oocyte development, follicular hormones, and ovulation in gilts fed high-energy diets

摘要: Previous research revealed that treatment with vitamin A approximately 5 d before ovulation may increase litter size in weaned sows and improve embryonal survival gilts fed high-energy diets reduced survival. For the current study, hypothesis was administration of would alter development follicles oocytes a way favorable to enhanced (Landrace x Large White) (Duroc Hampshire) (n = 44) were 11.0 Mcal ME gilt(-1) d(-1) beginning 7 after second estrus given (i.m.) corn oil or 1 10(6) IU (retinyl palmitate) on 15 estrus. Gilts checked for every 4 h, mated naturally at third estrus, assigned randomly undergo midventral laparotomy 24 28, 28 32, 32 36, 36 40 h onset At laparotomy, ovulated early-stage embryos recovered from oviducts, ovaries removed aspiration granulosa cells unovulated follicles. Oocytes stained assessment stage development. Granulosa cultured assess their ability secrete progesterone. Follicular fluid assayed progesterone, estradiol-17beta, IGF-I, PGF2alpha. Treatment altered by decreasing percentage germinal vesicle increasing advanced stages. Mean increased A, but variation decreased. Among matched meiotic oocyte, follicular concentrations PGF2alpha greater A-treated than controls, vivo did not affect LH-stimulated unstimulated secretion progesterone vitro. These data provide evidence influence embryonic advancing resumption meiosis altering hormonal environment during follicle maturation.