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Bioefficacy of hydroxy-selenomethionine in dairy cows.

N. L. Whitehouse




Bioefficacy of hydroxy-selenomethionine in dairy cows.
N. L. Whitehouse*1, J. R. Sexton1, S. M. Hollister1, L. H. P. Silva2, S. M. Fredin3, M. Briens1. 1University of New Hampshire Durham, NH, 2Adisseo USA Inc Alpharetta, GA, 3Adisseo France SAS Commentry, France.

Selenium (Se) is an essential trace mineral that if deficient in the soil will therefore be deficient in diets fed to dairy cows. Selenium supplements exists in inorganic and organic forms, with the organic form being seleno-yeasts (SY) or pure forms such as selenomethionine or hydroxy-selenomethionine (OH-SeMet). The objective was to determine the amount of Se that was transferred to milk and blood of mid to late lactation dairy cows when supplemental Se from a OH-SeMet (Selisseo 2% Se, Adisseo France SAS) was fed compared with an unsupplemented group and a group supplemented with a SY. Twenty-four lactating Holstein cows, 12 multiparous and 12 primiparous (178 � 43 d in milk (DIM)) were used in a randomized complete block design for 91 d (7 d for covariate and 84 d for treatments). Treatments were 1) basal (practical) diet with an expected Se background of 0.2 mg Se per kg as-fed (negative control), 2) basal diet + 0.3 mg Se per kg as-fed from SY (positive control SY-0.3), 3) basal diet + 0.1 mg Se per kg as-fed from OH-SeMet (OH-SeMet-0.1), and 4) basal diet + 0.3 mg Se per kg as-fed from OH-SeMet (OH-SeMet-0.3). Blood (at 1030h) and milk samples (am and pm milking) were obtained from each on the last 3 d of the covariate week and wk 1, 2, 3, 4, 6, 8, 10 and 12 of the study. Data were analyzed using the PROC MIXED procedures of SAS with REPEATED measures. Significance was declared at P ≤ 0.05. Plasma and milk Se concentrations was highest for OH-SeMet-0.3 (Table 1). However, there was no difference on the plasma glutathione peroxidase activity between groups. Those results are a confirmation that organic Se forms can increase milk and plasma Se concentrations. Moreover, when administered at the same level of supplementation, OH-SeMet showed to be more efficient than SY to improve those Se concentrations.Table 1. Average plasma and milk Se concentration and plasma glutathione peroxidase activity

ItemNegative controlPositive control SY-0.3OH-SeMet-0.1OH-SeMet-0.3P-value
Plasma Se, ng/mL120d134b122c142a<0.0001
Milk Se, ng/mL57d97b78c116a<0.0001
Glutathione peroxidase, nmol/mL90.5891.6391.0092.850.859
a—dMeans within rows differ at P < 0.05.

Keywords: selenium, selenomethionine, milk.