Effects of the Supplementation Period of Spent Composts of Selenium-enriched Mushrooms on Plasma Glutathione Peroxidase Activity and Selenium Deposition in Finishing Hanwoo Steers

摘要

This study was conducted to determine effects of different supplementation periods (2, 3 and 4 months) of spent composts of Se-enriched mushrooms (Se-SMC) on plasma glutathione peroxidase (GSH-Px) activity and selenium deposition of finishing Hanwoo steers for the optimal supplementing period determination in order to produce Se-fortified Hanwoo beef. In the present study, 30 Hanwoo steers were allotted to treatments in six groups of five steers per pen. Treatments were separated into control and Se-SMC for each supplementation period. Dietary selenium contents were 0.1 and 0.9 ppm for control and Se-SMC treatments, respectively. At the end of each supplementation period, steers by periods were slaughtered to collect hind leg and liver samples for their selenium analyses. Blood samples were taken to analyze whole blood Se concentration and plasma GSH-Px activity at the last day of each supplementation period. Dry matter intakes were unaffected by Se-SMC and supplementation periods. In addition, average daily gain was not different between control and Se-SMC treatments and among supplementation periods. There was no difference for total body weight gain between control and Se-SMC treatments within each supplementation period. The supplementation ofSe-SMC significantly (P<0.001) increased whole blood Se concentration, but whole blood selenium concentration was not affected by the supplementation period. Furthermore, plasma GSH-Px activity showed similar trend as shown in the pattern of whole bloodSe concentration, but no difference by supplementation periods was observed. Selenium contents in hind legs significantly (P<0.05) increased with increasing supplementation periods, and also they were significantly (P<0.001) higher for Se-SMC supplementation groups in comparison to controls. However, there was no difference for selenium contents of hind legs between three and four months supplementation. Selenium contents in livers tended to slightly increase with increasing supplementation periods with no significant difference, but they were significantly (P<0.01) higher for Se-SMC supplementation groups compared with controls within the same period. The results indicated that the optimal Se-SMC supplementation period for the selenium deposition inHanwoo steers might be around two or three months when we considered selenium contents in hind legs and livers.