Effects of various levels of dietary selenium on hybro-type chicks

Sodium selenite was fed in the diet in concentrations of 3, 1 and 0.50 ppm to hybro-type chicks for 4 weeks from the age of 7 d. The chemical's effects on growth and tissues were investigated. One and 3 ppm dietary levels of selenium caused depression of growth, fatty change, focal necrosis, congestion of the sinusoids and slight fibroplasia in the liver, congestion and degeneration and/or necrosis of the cells of the proximal renal tubules and of the cardiac muscle fibers and hemorrhage in the thigh and breast. These changes were accompanied by an increase in the activity of sorbitol and glutamic dehydrogenases (SDH and GDH) and in the concentration of potassium, and a decrease in the levels of total protein, calcium and zinc in the serum. Susceptibility to hemorrhage and damage to kidneys and liver persisted for 3 weeks after the test diet was withdrawn. One-half of 1 ppm-selenite meal produced no adverse effects on the chicks.