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United States Department of Agriculture

Agricultural Research Service

Title: Comparative Toxicosis of Sodium Selenite and Selenomethionine in Lambs

Authors
item Tiwary, A. - UC DAVIS
item Stegelmeier, Bryan
item Panter, Kip
item Hall, Jeffery - USU

Submitted to: Journal of Veterinary Diagnostic Investigation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 13, 2005
Publication Date: April 7, 2006
Citation: Tiwary, A.K., Stegelmeier, B.L., Panter, K.E., Hall, J.O. 2006. Comparative toxicosis of sodium selenite and selenomethionine in lambs. Journal of Veterinary Diagnostic Investigation.

Interpretive Summary: The movement of selenium (Se) was studied in serum and whole blood of lambs that were orally dosed with various doses of Se as sodium selenite (inorganic Se, NaSel) or selenomethionine (organic Se, SeMet). Thirty-two lambs were randomly assigned to eight treatment groups, with four animals per group. Se was administered at 0, 1, 2, or 3 mg/kg body weight, as either NaSel or SeMet. Control groups were given similar amounts of carrier or methionine and carrier. Blood and serum were collected at 0, 10 min, 30 min, 1 h, 3 h, 6 h, 12 h, 18 h, 1 d, 2 d, 3 d, 5 d, and 7 d after dosing. Resulting Se concentrations in both serum and whole blood from SeMet treatment groups were higher than those given equal amounts of Se as sodium selenite, with selenium concentrations of lambs dosed with SeMet peaking at 1.4 to 1.75 and 1.2 to 1.7 times that for NaSel, for serum and whole blood respectively. From the serum data, the half-life (t1/2) for absorption, distribution and elimination was found ranging from 2.5 to 5.4 h, 8.0 to 16.6 h, and 2.1 to 4.8 d, respectively, depending on the dose and type of Se administered. For the whole blood, the t ½ for absorption, distribution and elimination ranged from 2.5 to 5.7 h, 8.2 to 14.2 h, and 4.8 to 14.1 d. respectively. Based on the serum and whole blood kinetics, the rate of Se absorption was found to be greater for SeMet than for NaSel. The rates, however, reduced with increasing dose. The elimination rate increased with dose. The Se concentration in RBCs, mathematically determined from the whole blood and serum data, increased significantly 6 h after dosing with SeMet and remained statistically higher than the controls throughout the 7-d observation period. RBCs of lambs given NaSel did not appear to incorporate significant amounts Se during the first week post-dosing, and was non-significantly different from the controls at a = 0.05.

Technical Abstract: The kinetics of selenium (Se) was determined in serum and whole blood of lambs that were orally dosed with various doses of Se as sodium selenite (inorganic Se) or selenomethionine (organic Se, SeMet). Thirty-two lambs were randomly assigned to eight treatment groups, with four animals per group. Se was administered at 0, 1, 2, or 3 mg/kg body weight, as either sodium selenite or selenomethionine Control groups were given similar amounts of carrier or methionine and carrier. Blood and serum were collected at 0, 10 min, 30min, 1 h, 3 h, 6 h, 12 h, 18 h, 1 d, 2 d, 3 d, 5 d, and 7 d after dosing. Resulting Se concentrations in both serum and whole blood from SeMet treatment groups were higher than those given equal amounts of Se as sodium selenite, with selenium concentrations of lambs dosed with SeMet peaking at 1.4 to 1.75 and 1.2 to 1.7 time that for sodium selenite, for serum and whole blood respectively. From the serum data, the half-life (t½) for absorption, distribution and elimination was found ranging from 2.5 to 5.4 h, 8.0 to 16.6 h, and 2.1 to 4.8 d, respectively, depending on the dose and type of Se administered. For the whole blood, the t½ for absorption, distribution and elimination ranged from 2.5 to 5.7 h, 8.2 to 14.2 h, and 4.8 to 14.1 d, respectively. Based on the serum and whole blood kinetics, the rate of Se absorption was found to be greater for SeMet than for sodium selenite. The rates, however, reduced with increasing dose. The elimination rate increased with dose. The Se concentration in RBCs, mathematically determined from the whole blood and serum data, increased significantly 6 h after dosing with SeMet and remained statistically higher than the controls throughout the 7-d observation period. RBCs of lambs given sodium selenite did not appear to incorporate significant amounts of Se during the first week post-dosing, and was non-significantly different from the controls at a = 0.05.

Last Modified: 11/28/2014
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