PSII-31 Effects of restricted dietary intake on protein expression of oviductal glycoprotein 1 (OVGP1) in the oviductal ampulla of beef cows

Abstract

Abstract In vitro production of embryos (IVP) results in poor pregnancy rates, with 10 to 40% of embryos transferred surviving to term. Inclusion of oviductal fluid (OF) in the culture media improves success of IVP and pregnancy rates, but factors influencing OF composition are not well investigated. Therefore, we examined the effects of restricted maternal dietary intake on expression of oviductal glycoprotein 1 (OVGP1; or oviductin), a highly conserved glycoprotein involved in fertilization and early embryo cleavage. Multiparous nonpregnant beef cows were randomly assigned to one of 2 intake groups (n = 9 per group) designed to maintain [control (CON)] or lose [0.7 kg/d, negative (NEG)] body weight (BW) for 9 wk; for each cow, initial and final body condition score (BCS; 1–9 scale) and body weight (BW) were determined. Cows were estrus synchronized (Co-Synch + CIDR protocol) and slaughtered 3 d after synchronized ovulation. At slaughter, cross sections of the oviductal ampulla adjacent to the ovary containing the corpus luteum were fixed in neutral buffered formalin, embedded in paraffin, sectioned, and stained using a primary antibody against OVGP1 and fluorescently-labeled secondary antibody. Intensity of immunofluorescent staining for OVGP1 was quantified by image analysis, and differences between intake groups analyzed by t-test. Change (final – initial) in BCS and BW were greater for the NEG compared with CON cows (BCS: -1.06 vs. -0. 50, P< 0.03; and BW: -40.8 vs. -3.6 kg, P < 0.0001). The OVGP1 glycoprotein was expressed in the luminal epithelium of the ampulla, and site of expression did not differ between NEG and CON intake groups. Intensity of staining also did not differ (P >0.30) between NEG and CON intake groups (7.110 vs. 7.153 arbitrary intensity units; SEM = 0.059). Thus, restriction of maternal nutrient intake for 9 weeks did not influence protein expression of OVGP1, a major oviductal glycoprotein.