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United States Department of Agriculture

Agricultural Research Service

Title: Effect of Level and Source of Selenium on Size of Gravid Uterine Tissues in Growing Pregnant Lambs

Authors
item Ward, Marcy - NORTH DAKOTA STATE UNIV
item Caton, Joel - NORTH DAKOTA STATE UNIV
item Taylor, Joshua
item Reynolds, Lawrence - NORTH DAKOTA STATE UNIV
item Redmer, Dale - NORTH DAKOTA STATE UNIV

Submitted to: Society for Gynecologic Investigation
Publication Type: Abstract Only
Publication Acceptance Date: February 1, 2004
Publication Date: February 27, 2004
Citation: Ward, M.A., Caton, J.S., Taylor, J.B., Reynolds, L.P, Redmer, D.A. 2004. Effect of level and source of seleniumon size of gravid uterine tissues [abstract]. Journal of the Society for Gynecologic Investigation. 2:216A.

Interpretive Summary: The mechanism for the reduction of cell proliferation in both cancerous and healthy tissues from supranutritional levels of selenium is not fully understood. Therefore, the objective of this study was to determine the effects of selenium source (organic vs inorganic) and level (0.1 ppm, 3 ppm, and 15 ppm) on maternal and fetal placental tissues. Supranutritional (3 ppm) selenium supplementation reduced uterine, fetal, fetal membrane, and placental weights as well as placentome number. The organic source, high selenium wheat, had greater effects on uterine and fetal membrane weights then the inorganic source, selenate. The potentially toxic level of selenium (15 ppm; selenate) did not show dramatic differences in measured parameters compared with supranutritional (3 ppm; selenate) levels.

Technical Abstract: Several studies have shown that supranutritional levels of dietary selenium (Se) reduce the rate of tumor growth and cell proliferation in several kinds of cancers. The mechanism by which this occurs in both cancerous and healthy tissue has yet to be fully understood. To examine the effects of source (organic vs. inorganic) and level (0.1 ppm, 3 ppm, and 15 ppm) of dietary Se on maternal and fetal placental tissues, 32 pregnant Targhee ewe lambs (45.6 ± 10.5 kg, 330 ± 30 days of age) were randomly allotted to one of four treatments in a completely randomized design. Treatments consisted of Control (CON; 0.1 ppm), Se-Wheat (SW; 3 ppm), 3 ppm Selenate (S3), and 15 ppm Selenate (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 days of gestation. Formulation of SW and S3 (supranutritional levels) provided 75 ug/kg BW of Se, while S15 (toxic level) treatment provided 375 ug/kg BW of Se. At day 130 ± 10 days of gestation, ewes were slaughtered and tissues harvested. Weight of the uterus was less (P < 0.04) for Se-treated (SW, S3, and S15) compared with CON ewes (573.6 vs 695.9 ± 42.3 g), and also was less (P < 0.02 for SW compared with selenate (S3 and S15; 502.4 vs 609.2 g). Fetal weight was also less (P < 0.05) for Se treatments compared with CON ewes (3.34 vs 3.82 kg ± 0.30 g). For fetal membrane weight, Se-treated ewes were less (P < 0.09) than CON (237.2 vs 289.0 ± 24.8 g), and SW was less (P < 0.06) then S3 and S15 (202.7 vs 254.5 g). Placentome number was less (P < 0.02) in Se-treated compared with CON ewes (66.1 vs 80.9 ± 5.5). Placentome weight was also less (P < 0.02) in Se-treated ewes then CON ewes (252.3 vs 332.4 ± 29.3 g). From these data we conclude that supranutritional (3 ppm) levels of dietary Se reduce uterine, fetal, fetal membrane and placental weights, as well as placentome number. The organic source (high Se wheat) had greater effects on uterine and fetal membrane weights then inorganic (3 or 15 ppm selenate), but had similar effects on fetal and placental weights and placentome number. Potentially toxic levels of Se (15 ppm), did not show dramatic differences in these parameters compared with supranutritional (3 ppm) levels.

Last Modified: 10/24/2014