Effect of age on utilization of selenium by chickens

Utilization of selenium was examined in slow-growing laying-type chickens (SG) and in fast-growing broiler hybrids (FG) fed ad libitum on a diet with 265 mu g of selenium/kg, including 128 mu g of selenium added as sodium selenite. To 40 d of age, coefficients of selenium retention increased (P < 0.05) daily in the SG and FG groups by 0.76 and 0.61%, respectively. From 40 to 100 d, the regression coefficients were not significant. Coefficients of selenium retention and retention per unit of body gain were higher in SG chickens. The influence of age on selenium content in BW gain of birds was evident (P < 0.01). From 5 to 40 d, allometric coefficients were 1.444 and 1.070 for SG and FG, respectively, and from d 40 to 100 the corresponding values were 1.282 and 1.081, respectively.