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

Abstract

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

Retinoid‐dependent mRNA expression and poly‐(A) contents in bovine oocytes meiotically arrested and/or matured in vitro

“…The oocyte's developmental competence is enhanced by retinoid support during oocyte intrafollicular growth in the cow (Shaw et al, 1995), sheep (Eberhardt et al, 1999), and gilt (Whaley et al, 1997;Whaley et al, 2000), as in rabbits that have high levels of vitamin A (Besenfelder et al, 1996). In agreement with these findings, the addition of 9-cis-RA to in vitro maturation (IVM) cultures stimulated cortical granule migration in bovine oocytes both matured and meiotically arrested for a 24-hr culture period (Duque et al, 2002).…”

Oocytes recovered from cows treated with retinol become unviable as blastocysts produced in vitro

“…It has been reported that the developmental competence of the oocyte is enhanced by ROH treatment in the cow (Shaw et al 1995), sheep (Eberhardt et al 1999) and gilt (Whaley et al 1997(Whaley et al , 2000, as well as in rabbits that have high blood levels of vitamin A (Besenfelder et al 1996). In studies involving cows (Shaw et al 1995), sheep (Eberhardt et al 1999) and gilts (Whaley et al 1997(Whaley et al , 2000 the effects of retinol on follicular development were monitored and recorded 4 days post-administration.…”

“…In studies involving cows (Shaw et al 1995), sheep (Eberhardt et al 1999) and gilts (Whaley et al 1997(Whaley et al , 2000 the effects of retinol on follicular development were monitored and recorded 4 days post-administration. The reason why these standards were set are not described and the limits (length and dosage) of ROH treatment are unknown.…”

effect of ascorbic acid as a feed additive on indicators of the reproductive performance of Pulawska breed gilts

“…Mahan and Vallet (18) the stimulatory effect of various vitamins and minerals added to a feed on the sexual cycle of sows. A rapid growth and development of young growing gilts in their deficient diet during large-scale production could additionally affect the effect of increased weight of gilt's reproductive organs, which was achieved due to the administration of vitamin C. Vitamin C supplementation caused the increased levels of 17β-estradiol which influenced the growth and development of reproductive organs (6,40). Some authors (29,41) believe that backfat thickness above 16.0 mm is a prerequisite of good results in reproduction.…”