Calorimetric measurements on chickens given diets with a range of energy concentrations

Synopsis Eight diets with metabolisable energy (ME) concentrations ranging from 9–1 to 15–3 MJ/kg were given to groups of five chickens kept in respiration calorimeters for 3 to 4 d. Availability of ME ranged from 57% to 79%. One diet differed from the others, but for those groups of chickens on the other seven diets availability of ME was 80% when energy balance was negative and only 60% when positive. Protein synthesis appeared to continue when chickens were in negative energy balance and fat was frequently catabolised when birds were in positive energy balance, apparently to support protein synthesis.