Effects of dietary selenium source and level on selenium contents in blood, colostrum and milk and metabolic profile in dairy cows | Vpliv izvora in vrednosti prehranskega selena na raven selena v krvi, kolostrumu in mleku ter metabolni profil krav molznic
2009
Illek, J., Brno (Czech Republic). Univ. of Veterinary and Pharmaceutical Science | Kumprechtova, D. | Ballet, N.
The aim of the study was to compare the effects of two levels of selenium yeast (SY) and sodium selenite (SS) supplementation on blood, colostrum and milk Se levels, blood chemistry parameters in dairy cows under field conditions. The study included 35 Holstein cows from 5 weeks prepartum to 12 weeks postpartum. The cows were divided into 4 treatments (n=9): 1. Negative Control (NC) 8211; no Se supplement, 2. Positive Control (PC) - 0.3 ppm Se (from sodium selenite), S1 8211; 0.3 ppm Se (from selenium yeast - SELSAF (R), Lesaffre Feed Additives, France), 4. S2 - 5 ppm Se (SELSAF (R), Lesaffre Feed Additives, France). At 5 and 1 weeks prepartum, on the calving day, and 4, 8, 12 weeks postpartum, blood samples were taken and analysed for Se, GSH-Px, TP, billirubin, AST, GMT, CK. Colostrum and milk were collected on the calving day and 4, 8 and 12 weeks postpartum and analysed for Se content. Initial Se status in all the cows was marginal. NC cows showed suboptimal blood Se levels for the whole period under study. S1 and S2 showed significantly (P 0.01) higher values than NC and PC cows. Colostrum Se levels were significantly higher (P 0.01) in S1 (128.17 ug/l) and S2 (155.58 ug/l) than in NC (94.68 ug/l) and PC (99.3 ug/l) cows. Overall mean milk Se levels in S1 (20.4 ug/l) and S2 (50.0 ug/l) were higher (P 0.01) than in NC (10.9 ug/l) and PC (16.6 ug/l). GSH-Px activity in whole blood in S1 and S2 was higher than in NC and PC (P 0.01). TP, billirubin, AST and GMT did not significantly differ between the treatments and were within the physiological ranges. Se levels in whole blood, colostrum and milk, and GSH-Px activity were significantly increased by selenium yeast supplementation. The response was dose dependent and consistent. Selenium from organic source was more bioavailable than selenium from sodium selenite. Dietary organic Se at a tolerance dose (5 ppm) had no detrimental effect on the blood chemistry parameters analysed.
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