Development of hepatic microsomal mixed function oxidase system in male broilers fed a high or low protein diet

This experiment was undertaken to determine the changes in the mixed function oxidase system (MFO) in hepatic microsomes of male broiler chicks fed a 15% crude protein (LP) or 23% crude protein (HP) diet at different ages. The cytochromes P-450 and b5 content per unit of microsomal protein increased with age, while those per unit of body weight reached a maximum at 6 weeks of age, regardless of dietary protein levels. The activity of the MFO in chicks fed the HP diet was greater than those in chicks fed the LP diet during the first 9 weeks after hatching. At 4 weeks of age, cytochromes P-450 and b5, and NADPH-cytochrome c reductase were reduced by feeding the HP diet, but not by the LP diet.