The effects of dietary energy concentration on growth rate and conversion of energy to weight gain in broiler chickens

Publisher Website
Google Scholar
Abstract
Eight diets, their metabolisable energy (ME) concentrations ranging from 2.3 Mcal/kg to 3.6 Mcal/kg (9.6 to 14.1 MJ/kg) were fed to each of four pens of broilers in two trials. Food intake was inversely related to energy concentration but the ME required by each sex to reach a given live‐weight was quite similar. Birds on the diets with a medium energy concentration (about 3.1 Mcal/kg (13.0MJ/ kg)) required slightly less ME than those on other diets and generally reached the required live‐weight earlier than those on other diets. Birds in the first trial required less of any particular diet than their counterparts in the second trial, reflecting the lower ambient temperatures recorded during the latter trial. Mortality recorded from 14 d of each trial was generally lower for birds on the medium energy concentration diets and dressed carcass percentage higher than those on other diets. The results of the present study are in agreement with the recent recommendation (National Research Council, 1971) of 3.2 Mcal ME/kg (13.4 MJ/kg) for broiler diets. However, it is suggested that minimum and maximum values be given in such recommendations; this would allow greater flexibility and a wider range of ingredients in diet formulation.