|Taylor, Joshua - Bret|
Submitted to: Midwestern Section of the American Society of Animal Science
Publication Type: Abstract only
Publication Acceptance Date: 12/15/2003
Publication Date: 1/12/2004
Citation: Ward, M.A., Caton, J.S., Taylor, J.B., Lawler, T.L., Soto-Navarro, S.A., Reynolds, L.P. 2004. Effect of level and source of seleniumon mass and growth of maternal visceral tissues in growing pregnant ewe lambs [abstract]. Midwestern Section of the American Society of Animal Science. 1:62. Interpretive Summary: The objective of this study was to determine the effects of selenium source (organic vs inorganic) and level (0.1, 3, and 15 ppm) on maternal visceral tissues. Thirty two pregnant Targhee ewe lambs were used. Maternal visceral tissues, particularly jejunal mucosa, are responsive to supranutritional levels of selenium in the diet, especially when the source of selenium is organic.
Technical Abstract: To examine the effects of source (organic vs inorganic) and level (0.1 ppm, 3 ppm, and 15 ppm) of dietary Se on maternal visceral tissues, 32 pregnant Targhee ewe lambs (45.6 ± 10.5 kg; 330 ± 30 d) were randomly allotted to one of four treatments in a completely randomized design. Treatments consisted of Control (CON; 0.1ppm), Se-Wheat (SW; 3 ppm), 3 ppm Selenite (S3), and 15 ppm Selenite (S15). The SW diet was formulated using 32% high Se wheat (with a concentration of 8 ppm Se). All diets were similar in N and energy, and fed to meet or exceed nutritional requirements. Diets were initiated upon receiving, at 50 ± 5 d of gestation. Formulation of SW and S3 (supranutritional levels) provided 75 ug/kg BW of Se, while the S15 (toxic level) treatment provided 375 ug/kg BW of Se. At day 130 ± 10 of gestation, ewes were slaughtered and tissues harvested. Liver mass (g/kg; EBW), was greater (P < 0.10) in SW and S15 compared with CON (15.0, 17.4, 16.4, and 16.9; ± 0.64 g for CON, SW, S3, and S15 respectively). Blood volume (g) was less (P < 0.10) in SW and S3 versus CON; however, S15 did not differ from any other treatments. Liver protein (mg/g) concentrations were greater (P < 0.05) in SW and S15 versus CON (95.7, 111.9, 101.1, and 121.6 ± 5.5 g, for CON, SW, S3, and S15 respectively). Jejunal and small intestinal mass (g and g/kg maternal BW), was unaffected by treatment. Jejunal DNA (mg/g), however, was higher (P < 0.05) in CON tissue, versus SW and S3. Interestingly, jejunal mucosal DNA was higher (P < 0.05) in SW compared with CON (6.39 vs 5.19 ± .33 mg/g), indicating a greater number of jejunal mucosal cells present in SW treatment. In addition, mucosal protein:DNA and RNA:DNA ratios were lower (P < 0.05) in SW compared with CON (7.75 vs 5.85 ± 0.55; 0.86 vs 0.69 ± 0.05, respectively). These data indicate maternal visceral tissues are responsive to supranutritional levels of selenium in the diet, especially when the source of Se is organic. This appears to be particularly true in the case of jejunal mucosa.