PHYSIOLOGICAL APPROACHES TO INCREASE THE EFFICIENCY OF PORK PRODUCTION THROUGH IMPROVED NUTRITIONAL AND REPRODUCTIVE COMPETENCE
Location: Reproduction Research
Title: Conceptus development during embryo elongation in lines of pigs selected for ovulation rate or uterine capacity
Submitted to: Midwestern Section of the American Society of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: November 8, 2007
Publication Date: September 20, 2008
Citation: Miles, J.R., Freking, B.A., Blomberg, L., Vallet, J.L. 2008. Conceptus development during embryo elongation in lines of pigs selected for ovulation rate or uterine capacity [abstract]. Journal of Animal Science. 86 (E-Supplement 3):107 (Abstract #233).
The pig embryo undergoes a dramatic morphological transition between Day 10 and 12 of gestation, elongating from a spherical structure to a long, thin filament. Lines of pigs selected for increased uterine capacity (UC) have improved conceptus survival while pigs selected for increased ovulation rate (OR) have decreased conceptus survival relative to an unselected control line (CO). The objective of this study was to evaluate development during embryo elongation as a contributing factor to differences in conceptus survival rates among these pig lines. Conceptuses were recovered by flushing each uterine horn of pregnant gilts with 25 ml of PBS at Day 10 (n = 12, 13, and 13) or 12 (n = 7, 11, and 10) of gestation from CO, UC, and OR gilts, respectively. At Day 10 of gestation, conceptus diameter was determined and the standard deviation within individual gilts was used to assess conceptus morphologic diversity. Uterine flushings were assayed for total protein and estradiol-17beta at Day 10 and 12 of gestation. Morphological data were analyzed for analysis of variance with the fixed effects of line, season, and the interactions of fixed effects. Flushing data were analyzed for analysis of variance with the fixed effects of line, day, season, and the interactions of fixed effects. There were no significant line effects on conceptus diameter means or within-litter standard deviations at Day 10 of gestation. Furthermore, total protein or estradiol-17beta levels in uterine flushing at Day 10 and 12 of gestation were not different between the lines. Day effects were detected for total uterine luminal protein (P < 0.0001; 13.4 ± 0.5 and 32.2 ± 1.4 mg) and total uterine luminal estradiol-17beta (P < 0.0001; 1.2 ± 0.1 and 7.9 ± 1.0 ng) for Day 10 and 12, respectively. These findings indicate limited deviations in conceptus development during embryo elongation between these lines of pigs.