|Taylor, Joshua - Bret|
Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/1/2008
Publication Date: 4/1/2008
Citation: Neville, T.L., Ward, M.A., Reed, J.J., Soto-Navarro, S.A., Julius, S.L., Borowics, P.P., Taylor, J.B., Redmer, D.A., Reynolds, L.P., Caton, J.S. 2008. Effects of level and source of dietary selenium on maternal and fetal body weight, visceral organ mass, cellularity estimates, and jejunal vascularity in pregnant ewe lambs. Journal of Animal Science. 86:890-901. Interpretive Summary: We investigated the effects of selenium source and level on pregnant ewe lambs and their fetuses. Feeding supranutritional selenium, from either a selenium-salt or selenomethionine source, to pregnant ewes seems to alter, 1) intestinal-cell and -vascular growth in the pregnant ewe lamb and 2) liver, kidney, and intestinal development in the fetus.
Technical Abstract: Pregnant Targhee ewe lambs (n = 32; BW = 45.6 ± 2.3 kg) were allotted randomly to one of four treatments in a completely randomized design to examine effects of dietary-Se level and source on maternal and fetal visceral organ mass, cellularity estimates, and maternal jejunal crypt cell proliferation and vascularity. Diets contained (DM basis) either no added Se (CON) or supranutritional Se included as high Se-wheat at 3.0 ppm (SW) and sodium selenate included at 3 (S3) or 15 (S15) ppm Se. Diets were similar in CP (15.5%) and ME (2.68 Mcal/kg of DM), and fed to meet or exceed requirements. Treatments were initiated at 50 ± 5 d of gestation. The CON, SW, S3, and S15 treatment diets provided 2.5, 75, 75, and 375 ug Se/kg BW, respectively. On day 134 ± 10 of gestation, ewes were necropsied and tissues harvested. Orthogonal contrasts included CON vs. Se treatments (SW, S3, and S15), SW vs. S3, and S3 vs. S15 were used to evaluate differences between Se level and source. There were no differences in ewe initial and final BW. Full viscera and liver mass (g/kg empty BW and g/kg maternal BW) and maternal liver protein concentration (mg/g) and content (g) were greater (P < 0.04) in Se-treated compared with CON ewes. Maternal liver protein concentration was greater (P = 0.01) in SW ewes vs. S3, and content was greater (P = 0.01) in S15 compared with S3 ewes. Maternal jejunal mucosal DNA concentration (mg/g) was greater (P = 0.08) in SW compared with S3 ewes. Total number of proliferating cells in maternal jejunal mucosa was greater (P = 0.02) in Se-fed compared with CON ewes. Capillary number density within maternal jejunal tissue was greater (P = 0.08) in S3 compared with SW ewes. Selenium treatment resulted in reduced fetal heart girth (P = 0.08). Fetal kidney RNA (P = 0.04) and protein concentrations (mg/g; P = 0.03) were greater in Se-treated compared with CON ewes. These results indicate that supranutritional dietary Se increases maternal-jejunal mucosa cell number through increased crypt cell proliferation. No indications of toxicity were observed in any of the selenium treatments.