Effects 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 conceptuses. In the first, 91 second-estrus gilts were inseminated 24 h after detection of standing estrus and randomly assigned to a recommended 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 recovered conceptuses (n = 977) were recorded. Conceptuses were photographed, and surface areas were measured using an image analysis system. Standard 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) concentrations by enzymeimmunoassay. Conceptus survival was similar for RE and HE groups (76.2 +/- 21 vs 78.8 +/- 17.5%; P > .05). Mean surface areas and SD increased (P < .05) between d 9 and 11, but they were the same 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 +/- .40 vs 1.29 +/- .39 ng/mL; P < .01).(ABSTRACT TRUNCATED AT 250 WORDS)