Evidence that injection of vitamin A before mating may improve embryo survival in gilts fed normal or high-energy diets.

Abstract

The hypothesis was that administration of vitamin A before ovulation would improve embryo survival in gilts fed a high-energy diet intentionally to reduce embryo survival. Forty crossbred ([Landrace x Large White] x [Duroc x Hampshire]) gilts were fed control (5.5 Mcal ME/d) or high-energy (11.0 Mcal ME/d) diets from 7 d after second estrus until 11 to 12 d after third estrus. Gilts in each dietary group received (i.m.) corn oil or retinyl palmitate (1 x 10(6) IU, vitamin A) on d 15 after second estrus and were mated at third estrus. Blood for determination of progesterone and estradiol was collected twice daily. The uterus and ovaries were removed on d 11 or 12 after third estrus for assessment of number of CL, and number, size and aromatase activity of embryos. Neither diet nor vitamin treatment affected number of CL. The high-energy diet exerted a negative effect on number of embryos (P = .09) and embryo survival (P = .07), whereas vitamin A exerted a positive effect on number of embryos (P = .07) and embryo survival (P = .08). The high-energy diet increased variation in embryo diameter, whereas vitamin A reduced variation in diameter and increased average diameter. Neither diet nor vitamin treatment influenced aromatase activity of embryos. Diet and vitamin treatment interacted with day to influence serum progesterone, but not estradiol. Injecting vitamin A before estrus restored embryo survival to normal levels in gilts fed high-energy diets, and this may be attributable to decreased variation in size of embryos.

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

“…Recently, RA treatment during the pre-implantation period in the mouse (Huang et al 2001(Huang et al , 2003 was shown to cause developmental retardation, inhibition of cell proliferation and induction of apoptosis. In previous reports, development of blastocysts to term was not analysed (Shaw et al 1995, Whaley et al 1997, Eberhardt et al 1999, and the precise stage (oocyte, embryo or both) during which retinoids exerted their effects was not determined. Our results involving oocytes isolated by OPU following ROH treatment and subsequently cultured in vitro demonstrate that ROH can influence development by acting on the oocyte during its intrafollicular growth.…”

“…Our results involving oocytes isolated by OPU following ROH treatment and subsequently cultured in vitro demonstrate that ROH can influence development by acting on the oocyte during its intrafollicular growth. In the future, it would be interesting to find out the outcome had the oocyte following ROH treatment been fertilized in vivo and the embryo recovered at specific stages during pre-implantation development, as done in earlier studies (Shaw et al 1995, Besenfelder et al 1996, Whaley et al 1997, Eberhardt et al 1999.…”

“…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.…”