Effects of excessive levels of sodium selenite on daily weight gain, mortality and plasma selenium concentration in chickens

Abstract

One hundred and five, one day old unsexed Hybro chickens divided into 7 groups, were fed basal diets supplemented with 0, 2, 5, 10, 20 and 30 mg Se/kg as sodium selenite for 6 weeks. The Se level of 2 mg/kg feed had no effect on chicken daily weight gain. The lowest level at which dietary Se caused reduction in daily gain was 5 mg/kg. Diets supplemented with 10, 15 and 20 mg Se/kg produced 24.5, 62.7 and 96.6% reductions in daily gain, respectively. Lower gains were evident within the first 11 days for chickens fed diets with 20 or 30 mg Se/kg and after 11 days for those provided with 10 or 15 mg Se/kg. Daily gain for the chickens fed the diet with 5 mg Se/kg was significantly lower only in the fifth week of fattening. Feeding diets with 15, 20 and 30 mg Se/kg caused 26.7 60 and 80% mortality, respectively Plasma Se concentrations were increased in all groups given supplementary Se. Maximal plasma Se levels between 220 and 300 mu g/l were reached on the 11th day (except for the group with 2 mg Se/kg) and at that level were maintained to the end of the experiment.