EFFECT OF INCREASED DIETARY ENERGY AFTER MATING ON DEVELOPMENTAL UNIFORMITY AND SURVIVAL OF PORCINE CONCEPTUSES

Two experiments were conducted to examine the effect of the feeding of a high-energy diet during early gestation on survival of porcine conc eptuses. In the first, 91 second-estrus gilts were inseminated 24 h af ter detection of standing estrus and randomly assigned to a recommende d energy (RE: 22.2 MJ of DE/d) or high-energy diet (HE: 36.0 MJ of DE/ d) obtained by addition of cornstarch to RE. Gilts were slaughtered 9, 10, or 11 d later, and numbers of corpora lutea (n = 1,268) and recov ered conceptuses (n = 977) were recorded. Conceptuses were photographe d, and surface areas were measured using an image analysis system. Sta ndard deviations (SD) for mean areas from 82 litters with 899 embryos were used as a measure of size variability within and between litters, and 472 of these were cultured for measurement of estrogen (E) concen trations by enzymeimmunoassay. Conceptus survival was similar for RE a nd HE groups (76.2 +/- 21 vs 78.8 +/- 17.5%; P > .05). Mean surface ar eas and SD increased (P < .05) between d 9 and 11, but they were the s ame for both diets (P > .1). No difference was detected between diets in E produced by d 9 and 10 blastocysts after 24 h in vitro (P > .1). In contrast, d-11 RE embryos produced more E than did HE embryos after 3 h (.77 +/- .11 vs .37 +/- .11 ng/mL; P < .01) and 24 h (3.02 +/- .4 0 vs 1.29 +/- .39 ng/mL; P < .01). In a second experiment, 47 gilts we re fed the same diets as in Exp.1 but were slaughtered on d 25 to dete rmine whether the difference in E production measured on d 11 affected subsequent embryonal survival. On d 25, fecal samples were collected and conceptuses (n = 537) were recovered. Conceptus survival (81 vs 74 %) and fecal estrogen concentration (28.7 vs 24.1 ng/g) were similar ( P > .10) for both diets. Combined results indicate that in adequately fed gilts, increased dietary energy after mating does not affect conce ptus survival during early gestation.