The effect of selenium or vitamin E supplementation on volatile fatty acid content of rumen liquor in sheep fed a purified diet.

Twelve crossbred wethers, four per diet, were allotted at random as follows: (1) purified control diet; (2) purified diet plus a weekly oral dose of 1 mg sodium selenite per sheep; (3) purified diet plus a weekly oral dose of 1000 l.U. vitamin E. The wethers were maintained on the diets for six months. Weight gains during the initial 140 days of the experiment were significantly greater in selenium (Se)-supplemental sheep than in the others. The rumem liquor from the untreated sheep contained lower proportions (molar %) of acetic acid than from the Se or vitamin E-supplemented sheep and had higher butyric acid concentration than the Se-supplemented sheep. Concentrations of acetate, butyrate and valerate were higher in vitamin E than in Se-supplemented sheep. In addition, the concentration and molar percent of isovaleric acid was significantly higher in Se-supplemented sheep than in the other sheep.