Combined Supplementation of Two Selenium Forms (Organic and Inorganic) and Iodine in Dairy Cows' Diet to Obtain Enriched Milk, Cheese, and Yogurt.

Simple Summary: Selenium and iodine are two microelements necessary for a normal thyroid hormone metabolism, and their deficiency in human diets can result in a significant health problem. Milk is a good vehicle for mineral enrichment and an available food for the general population. Thus, the main objective of this study was to evaluate the combined dietary intake of iodine and two chemical forms of selenium in dairy cows, at the maximum levels permitted in the European Union, in order to obtain milk, cheese, and yogurt naturally enriched in these microminerals. As a result, animal performance and the overall health status of cows were not negatively affected by the diets. However, selenium and iodine were successfully transferred to milk, increasing the level of both minerals in cheese and increasing the iodine level in yogurt, without harming the quality or acceptance. Therefore, the value-added products obtained could contribute in a realistic way to improve the current supply in the market to enhance the intake of selenium and iodine in the human population. This study evaluated the effects of dietary supplementation in dairy cows with two Se forms (organic and inorganic) and I at the maximum levels permitted in the European Union, with the aim to obtain naturally enriched milk and derived products. A total of 20 Holstein Friesian cows in lactation were fed 2 diets for 64 days: a control diet with a supply of 0.57 mg of inorganic Se and 0.57 mg of I per kg of ration in dry matter (DM), and an experimental diet (SeI) with a supply of 0.34 mg of inorganic Se, 0.23 mg of organic Se, and 5.68 mg of I per kg of ration in DM. The SeI diet did not modify the performance or, in general, the metabolic profile of cows. Se and I levels in milk were affected by diet type and time of measurement (p < 0.01). Thus, a marked increase of both microminerals was evident between the beginning and the end of the test, when the SeI diet was administered. For Se, this increase ranged from 1.95 to 3.29 μg/100 g of milk; and for I, from 19.69 to 110.06 μg/100 g of milk. The SeI diet increased (p < 0.01) the Se and I content in the cheese, reaching levels of 16.4 μg/100 g for Se and 269.7 μg/100 g for I. An increase in I was observed in yogurt from the SeI diet (p < 0.001). The supplementation of two forms of Se and I in the cows' ration, at the levels evaluated, produced milk and dairy products enriched in these microelements without altering their quality parameters. However, a responsible intake of these products is necessary to avoid risks of deficiencies or excesses that could negatively affect the health of consumers. [ABSTRACT FROM AUTHOR]