Four experimental
treatment groups were planned: basal diet (BD), BD+His, BD+ASX, and BD+ASX+His, with four chicks (5 days old) in each group and
three replications (i.e., a total of 12 chicks per group). The BD was supplemented with either 0.4% His or 100 ppm ASX. The birds were
fed ad libitum for 3 weeks, and diets contained no antimicrobial compounds. Supplementing the diet with His significantly decreased
body weight gain, but increased the weights of the gizzard and proventriculus of the chicks as compared with those of chicks in the BD
group (p