Effects of strain, antibiotic supplement and diet calcium level on chick growth and feed conversion and on utilization of dietary energy and nitrogen

Abstract

The effects of two antibiotics and four calcium levels on body weight, feed consumption and conversion, metabolizable energy, and nitrogen retention of two commercial broiler strains were examined in an experiment conducted from day-old to eight weeks of age. Comparable growth rates were obtained for both strains on diets containing from 1.1 to 1.7 per cent calcium. Efficiencies of feed conversion and metabolizable energy and nitrogen retention values were not significantly influenced by diet calcium level. Although both antibiotics gave comparable weight gains and efficiencies of feed conversion, metabolizable energy and nitrogen retention were significantly higher when bacitracin was fed as opposed to chlortetracycline. More energy was metabolized and more nitrogen was retained per unit of diet by the slower growing broiler strain.