Item – Theses Canada

​
OCLC number
1007094213
Link(s) to full text
LAC copy
LAC copy
Author
Novak, Susan,1972-
Title
The role of the oviduct in embryonic survival in the gilt.
Degree
Ph. D. -- University of Alberta, 2000
Publisher
Ottawa : National Library of Canada = Bibliothèque nationale du Canada, [2002]
Description
3 microfiches
Notes
Includes bibliographical references.
Abstract
The potential role of the oviduct in nutritionally-mediated, and locally regulated effects on embryonic survival was investigated. In the first experiment, time after ovulation was correlated (r = 0.79, P = 0.0001) with peripheral, but not oviductal, progesterone concentrations suggesting that nutritional effects on peripheral progesterone are temporally different to effects within the ovarian and oviductal vasculature. Two experiments established temporal and steroid-dependent changes in the oviduct during the peri-ovulatory period. Temporally, protein and insulin-like growth factor (IGF)-I concentrations in oviduct flushings decreased (P < 0.01), and porcine oviductal secretory protein (POSP) mRNA and protein abundance was lowest (P = 0.001) on d 2 after ovulation, coincident with changes (P = 0.0001) in plasma progesterone concentrations and the estrogen: progesterone (E-P) ratio. Unilaterally ovariectomized gilts were used to study local steroid dependent regulation of oviduct function. Plasma steroids were higher (P < 0.001) in oviductal veins ipsilateral (INT) than contralateral (OVX) to the remaining ovary, confirming sub-ovarian countercurrent transfer of steroids in vivo. Protein concentration was higher (P = 0.031) and POSP abundance was lower (P = 0.0001) in OVX than INT oviductal flushings. Two final experiments determined whether nutritionally-induced changes in embryonic survival could be mediated by oviduct function. Using an established experimental paradigm that results in differences in embryonic survival and progesterone status in the immediate post-ovulatory period, gifts were restrict fed in the first (RH) or second week (HR) of the estrous cycle. In this study, protein concentration increased (P = 0.002) in oviduct flushings, coincident with a higher (P < 0.05) E:P ratio in peripheral plasma in the RH group. The second study used the same nutritional paradigm, plus a third insulin-treated group. HR had lower (P < 0.05) E:P ratio, estradiol, and IGF-I concentrations in oviductal plasma, lower protein and IGF-I concentrations, and POSP abundance in oviduct flushings (P < 0.01), and lower (P < 0.05) POSP and IGF binding protein (IGFBP)-4 mRNA in oviduct tissue compared to RH. Insulin treatment differentially affected the oviduct environment by lowering (P = 0.0001) POSP abundance, and increasing (P = 0.026) IGFBP-4 mRNA compared to HR gifts. Previous feed restriction and insulin treatment affects the oviduct environment and may contribute to nutritional effects on embryonic survival.
ISBN
0612596478
9780612596474