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 lambs1

Abstract

Pregnant Targhee ewe lambs (n = 32; BW = 45.6 +/- 2.2 kg) were allotted randomly to 1 of 4 treatments in a completely randomized design to examine the effects of level and source of dietary Se 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 (control) or supranutritional Se from high-Se wheat at 3.0 ppm Se (SW) or from sodium selenate at 3 (S3) or 15 (S15) ppm Se. Diets were similar in CP (15.5%) and ME (2.68 Mcal/kg of DM) and were fed to meet or exceed requirements. Treatments were initiated at 50 +/- 5 d of gestation. The control, SW, S3, and S15 treatment diets provided 2.5, 75, 75, and 375 microg of Se/kg of BW, respectively. On d 134 +/- 10 of gestation, ewes were necropsied, and tissues were harvested. Contrasts, including control vs. Se treatments (SW, S3, and S15), SW vs. S3, and S3 vs. S15, were used to evaluate differences among Se levels and sources. There were no differences in ewe initial and final BW. Full viscera and liver mass (g/kg of empty BW and g/kg of maternal BW) and maternal liver protein concentration (mg/g) and content (g) were greater (P < 0.04) in Se-treated compared with control ewes. Maternal liver protein concentration was greater (P = 0.01) in SW vs. S3 ewes, 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 control 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 control ewes. These results indicate that supranutritional dietary Se increases cell numbers in maternal jejunal mucosa through increased crypt cell proliferation. No indications of toxicity were observed in any of the Se treatments.

Nutritional plane and selenium supply during gestation affect yield and nutrient composition of colostrum and milk in primiparous ewes1

“…Within each Se and nutritional plane treatment, one-half of the ewes were assigned to be slaughtered and necropsied after colostrum sampling (between 3 and 24 h postpartum), and the remaining ewes were mechanically milked twice daily for 20 d. This resulted in a completely randomized design with a 2 × 3 factorial arrangement of Se supply × nutritional plane (ASe-RES, ASe-CON, ASe-HIH, HSe-RES, HSe-CON, HSe-HIH; n = 14 ewes/treatment for colostrum measures, n = 7 ewes/treatment for early lactation measures). Selenium treatments were based on NRC requirements (ASe), and nontoxic supranutritional amounts of Se (HSe) that have previously elicited biological response in ruminants (Soto-Navarro et al, 2004;Reed et al, 2007;Neville et al, 2008;Carlson et al, 2009).…”

“…In this research model, nutritional plane during gestation has affected ewe endocrine profiles. Nutrient-restricted ewes had decreased IGF-I (Ward et al, 2008), progesterone Lekatz et al, 2010), and thyroid hormones (Ward et al, 2008;Lekatz et al, 2010), whereas ewes fed a high nutritional plane had decreased estradiol and progesterone but increased prolactin (Camacho et al, 2010) and cortisol during gestation. These alterations in hormones likely interact to play a role during the crucial mammary growth and development of gestation Banchero et al, 2006).…”

“…Maternal changes in body composition Carlson et al, 2009;Meyer et al, 2010b), endocrine and metabolic status (Ward et al, 2008;Lekatz et al, 2010), and colostrum yield and nutrient content (Swanson et al, 2008) have accompanied changes observed in offspring. Therefore, we hypothesized that gestational nutrition alters the subsequent milk production of the dam, even when nutrient requirements of lactation are met.…”

Feeding value of nontoxic Jatropha curcas seed cake for partially replacing dry-rolled corn and soybean meal in lambs fed finishing diets

“…Previous data suggests that there is very little variation among fresh and dry weights for visceral organs (Neville et al, 2008). Organ mass was expressed as grams of fresh tissue per kilogram of final EBW.…”

Effects of maternal plane of nutrition and increased dietary selenium in first-parity ewes on inflammatory response in the ovine neonatal gut1

“…Soil Se concentrations can directly affect the Se concentration in the plants consumed by grazing ruminants. Adequate dietary Se is necessary for proper growth, reproduction, and performance, and Se deficiency results in debilitating and fatal disease conditions in human and animals (Levander and Burk, 1986), whereas excessive intake of Se causes toxicity (Schwarz et al, 1957;Neville et al, 2008). Improper maternal nutrient supply during gestation affects fetal gut development (Trahair et al, 1997) and neonatal and postnatal outcomes (Wu et al, 2006).…”