A study was made of the effects of barley feeds containing varying levels of natural grain selenium derived from fertilizer and of the effects of sodium selenite on selenium concentrations in the tissues of growing pigs and on the histological structure of myocardium and longissimus muscle. The results indicated that organic grain selenium affects the selenium levels of porcine tissues significantly more than sodium selenite supplementation of the same amount. The organic selenium concentrations of feed and organs were found to be linearly correlated. Spleen, lung and heart were the most reliable indicators of tissue selenium level in pigs. The selenium concentration of muscles of pigs fed on naturally seleniferous feed (270 µg Se/kg DM) was at the internationally level (500 µg Se/kg DM in meat), whereas the same amount of selenite in feed increased the selenium level of muscle only slightly (to 200/µg Se/kg DM). The histological structures of heart and muscle of pigs fed on naturally seleniferous feed were normal, whereas in the selenite group there were signs of muscle dystrophy when the selenium level was below 200 µg Se/kg DM. In addition, the pigs given selenite were subsequently placed in a lower, fat-containing carcass class. Feed with a natural organic selenium level of 150—200 µg Se/kg DM is preferred to selenite selenium supplement in pork production.
Effects of barley-bound organic selenium compared with inorganic selenite on selenium concentration and structure of tissues in pig
