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Interpretive Summary: Selenium decreased cholesterol levels

By: Caitlin Vonderohe

A major goal in animal agriculture is to improve the nutritional value of animal products. One area of focus in the beef cattle industry is to use supplemental selenium to improve the antioxidant abilities of muscle and liver tissue, which may reduce the cholesterol levels of muscle tissue, resulting in a healthier product. The primary measures of antioxidant capabilities of muscle tissue assesses the activity of glutathione peroxidase, which also reflect the amount of cholesterol in the tissue. A recent paper, published in the Journal of Animal Science by da Silva et al. explored the effects of different selenium sources and doses on glutathione peroxidase activity and cholesterol levels in beef cattle. The authors hypothesized that selenium supplementation would improve glutathione peroxidase activity and decrease cholesterol levels in muscle tissue. 

To query this hypothesis, investigators fed 63 Nellore bulls a common diet, supplemented with either an inorganic (sodium selenite) or organic source of selenium at one of three doses, or a control diet where selenium was not supplemented. Bulls remained on test diets for 90 days, and tissue was collected for assessment of glutathione peroxidase activity and markers of cholesterol metabolism in blood and muscle tissue. 

Bulls that received supplemental selenium, regardless of source, had higher levels of glutathione peroxidase in their muscle tissue, and lower levels of cholesterol. Selenium-supplemented bulls also had greater anti-oxidant and selenium in the liver. The bulls fed the organic selenium source had greater levels of antioxidants in the liver compared to the inorganically sourced selenium. Overall these results indicate that selenium supplementation may represent an alternative strategy to decreased cholesterol levels  in meat products, but more research needs to be done to fully understand the metabolic pathways involved in this phenomenon and the utility of this strategy in the market.