|Taylor, Joshua - Bret|
Submitted to: Journal of Animal Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/31/2013
Publication Date: 5/1/2013
Citation: Yunusova, R.D., Neville, T.L., Vonnahme, K.A., Hammer, C.J., Reed, J.J., Taylor, J.B., Redmer, D.A., Reynold, L.P., Caton, J.S. 2013. Impacts of maternal selenium supply and nutritional plane on visceral tissues and intestinal biology in 180 day-old offspring in sheep. Journal of Animal Science. 91:2229-2242. Interpretive Summary: Forage quality and availability, which are driven by climatic conditions, soil chemistry and rangeland management, can vary greatly when sheep are pregnant. Nutrient intake during pregnancy can have both positive and negative effects on the dam and, more importantly, the offspring. Based on the literature, maternal nutritional status during pregnancy is a major contributing factor in developmental outcomes in offspring. The objectives of this study were to determine the effects of deficient, adequate, or excessive macro (energy and protein) and micro (selenium) nutrient intake during pregnancy on intestinal development and growth of subsequent offspring at 180 days of age. Based on the data, maternal nutrient intake during pregnancy affected visceral organ development and intestinal biology in 180-day-old offspring. Specifically, deficient and excessive macro nutrient intake during pregnancy appeared to reduce total crypt cell proliferation and measures of vascularization in the intestinal villi of offspring at 180 days of age. No toxic effects were observed when selenium was provided at >10-fold the daily requirement. These results suggest that despite the similar postnatal environment, visceral tissues in the offspring were increasingly sensitive to maternal nutrition during pregnancy.
Technical Abstract: Objectives were to investigate the effects of maternal Se supply and nutritional plane during gestation on offspring visceral tissues and indices of intestinal growth, vascularity, and function at 180 d of age. Rambouillet ewe lambs (n = 82, approximately 240 d of age; 52 ± 0.8 kg BW at breeding) were allocated to a 2 × 3 factorial arrangement of treatments. Treatments included dietary Se (adequate Se [ASe, 9.5 µg/kg BW] or high Se [HSe, 81.8 µg/kg BW]) initiated at breeding and nutritional plane (60% [restricted, RES], 100% [control, CON], and 140% [ high, HI] of requirements) initiated at d 50 of gestation. Ewes were fed pelleted diets and housed individually indoors. At parturition, lambs were immediately removed and fed artificial colostrum for the first 20 h followed by ad libitum milk replacer. At 180 ± 2 d of age, lambs were euthanized and tissues harvested. Birth weight was affected by nutritional treatments (P < 0.001) with decreased birth weight in RES and HI compared with CON. Offspring from RES and HI ewes had decreased (P = 0.07) blood volume compared to CON, and those born to HSe ewes had increased (P < 0.04) total visceral adiposity (g/kg empty BW). Within offspring from CON ewes, those from HSe ewes had greater (P < 0.02) intestinal mass compared with ASe ewes. Within offspring from HSe ewes, both RES and HI had reduced (P = 0.05) intestinal mass compared with CON. Jejunal capillary area density was greater (P = 0.08) in offspring from ewes fed HSe compared with ASe. In addition, area per capillary was greater (P = 0.09) in CON compared with RES. Maternal nutritional plane tended (P = 0.11) to alter total small intestinal vascularity, with lambs from CON being greater than RES. Expression of most mRNA for measured angiogenic factors and receptors was not altered (P = 0.13) by maternal treatments; however expression of glucagon like peptide -2 (GLP-2) was lower (P = 0.07) in offspring from RES compared with CON ewes. Offspring from ewes fed HI diets had increased (P = 0.08) jejunal mucosal maltase activity. In conclusion, maternal Se supply and nutritional plane during gestation resulted in measurable changes in offspring visceral tissues and intestinal biology including perirenal fat, blood volume, intestinal mass, total jejunal crypt cell proliferation, area per capillary in jejunal villi, GLP-2 mRNA expression, and maltase activity at 180 d. Additional work is needed to determine impacts on intestinal function and nutrient uptake.