Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: March 25, 1997
Publication Date: N/A
Technical Abstract: The uterine endometrium secretes a variety of proteins in preparation for maternal recognition of pregnancy, implantation and embryonic/fetal development. Progesterone is responsible for stimulating synthesis of uterine proteins but the endometrial secretory response to periimplantation conceptus estrogen is not understood. The objectives were to: 1) compare total protein, retinol binding protein (RBP) and UF in uterine flushings o white crossbred and Meishan gilts and 2) determine whether the presence of the conceptuses influences the onset of uterine protein secretion between Day 10 and 16 of pregnancy. White crossbred (n=46) and Meishan (n=44) gilts with a normal estrous cycle (17 to 23 d) were checked for estrus twice daily and were randomly assigned to remain cyclic or to be mated (status effect) on the 1st and 2nd d of estrus (1st d = 0). Gilts were slaughtered on Day 10, 11, 12, 13, 14, 15 or 16. At slaughter, the uterus was collected dand each uterine horn was flushed with 20 ml .1x leucine minimal essential medium. Uterine flushings were assayed for total protein, RBP and UF (acid phosphatase assay). Heterogeneity of regression indicated that secretion patterns over time for total protein, RBP and UF in uterine flushings differed (p<.05) for white crossbred and Meishan gilts. Data indicated that RBP and UF contents were greater in white crossbred than Meishan gilts and total protein, RBP and UF increased with hours post estrus. The presence of conceptuses did not influence RBP and UF content in uterine flushings of gilts of either breed. These data show that changes in uterine protein secretion occur more gradually in Meishan compared to white crossbred gilts. It is hypothesized that this breed difference may influence the prolificacy of the Meishan breed by slowing conceptus development.