Effect of dietary protein source and monensin on performance of chicks

The effects of dietary protein source and monensin on growth performance of chicks fed diets containing 121 or 160 mg/kg monensin were investigated. Crossbred chicks (New Hampshire X Columbian) were fed a corn soybean meal diet (24% crude protein) containing 0, 5.0, or 13.0% animal-source protein supplied by various combinations of fish meal and meat and bone meal. Growth rate and gain/feed ratio were measured from 8 to 22 days posthatching. Growth performance was depressed by both 121 and 160 mg/kg monensin with the depression being greater at 160 mg/kg. The type or level of animal-source protein had no effect on the magnitude of growth depression caused by monensin. Growth performance was improved by addition of fish meal and meat and bone meal to the corn-soybean meal diet.