Abstract #M185

# M185
Effects of feeding a rumen-protected methionine on plasma amino acid concentrations, glandular morphology, and immunolabeling in the bovine endometrium.
S. L. Stella*1, D. A. V. Acosta2, C. Skenandore1,3, B. Q. Pinto1, Z. Zheng1, D. Luchini4, F. C. Cardoso1, 1University of Illinois, Urbana, IL, 2The Colombian Corporation for Agricultural Research (CORPOICA), Bogotá, Colombia, 3Texas A&M College of Veterinary Medicine, College Station, TX, 4Adisseo NACA, Alpharetta, GeoGArgia.

Glandular and immune function of the uterus are required for reproductive success in dairy cows. The objective of this study was to evaluate the impact of feeding a rumen-protected methionine, Smartamine M (RPM), on amino acid (AA) concentrations, glandular morphology, and immunolabeling of glutathione peroxidase 1 antibody (GPX) and superoxide dismutase 1 antibody (SOD). Multiparous Holstein cows (n = 20) were randomly assigned to 2 treatments starting at 21 d before calving until 73 DIM. Treatments were: CON (n = 9, fed the close-up and lactation diets with a Lys:Met = 3.5:1) and MET (n = 11, fed the basal diet+RPM to a Lys:Met = 2.8:1). Uterine endometrial biopsies and blood samples from the coccygeal artery or vein were collected at 15, 30, and 73 DIM. Images were captured using whole image scanning and quantification of glandular area, epithelial height, number of cells per gland, and percentage of positively immunolabeled cells were obtained. Median values were used as cutoff values for high/low scoring during frequency analysis. Statistical analysis were performed using the MIXED and FREQ procedures of SAS. CON had lower (P < 0.01) methionine plasma concentrations (18.05 ± 2.0 μmol/mL) than MET (30.39 ± 1.6 μmol/mL). CON had higher (P < 0.01) cystine plasma concentrations (3.62 ± 0.3 μmol/mL) than MET (2.8 ± 0.3 μmol/mL). An overall treatment by DIM interaction was observed for glandular epithelial height and number of cells per gland: CON (11.76 ± 2.0 μm) had higher (P = 0.03) glandular epithelial height than MET (10.45 ± 1.7 μm) and CON (16.0 ± 2.8) had higher (P = 0.03) number of cells per gland than MET (13.81 ± 2.5). Statistical differences were not observed for glandular area (P > 0.19), GPX (P > 0.18), or SOD (P > 0.89). Frequency analysis for samples having a high or low score of positively immunolabeled cells for GPX revealed a tendency (P = 0.08) at 15DIM for CON (n = 4) having increased chances of having a high score as compared with MET (n = 1). Supplementation of RPM altered the plasma AA concentrations, uterine glandular morphology, and results in increased immunolabeling of GPX at 15DIM for dairy cows.

Key Words: methionine, uterus, immunolabeling