INFLUENCE OF ENERGY INTAKE ON DEVELOPMENT OF BROILER BREEDER PULLETS

Abstract

One hundred and two broiler breeder pullets were reared from 10 wk of age on one of three diets formulated to contain 15% CP and provide 10.67, 11.72, or 12.89 MJ ME kg−1. All birds received the same daily feed allotment. At 20 wk of age, the pullets were light-stimulated and nine birds per treatment were slaughtered for carcass analysis. The remaining birds were slaughtered for carcass analysis at the time that they laid their first egg. Twelve birds from each treatment were blood sampled from 10–25.5 wk of age and plasma luteinizing hormone levels determined. While all birds had similar ages at first egg, birds given the high energy diet grew faster and had more fat, protein and fat-free mass in the body at first egg relative to birds consuming the least amount of energy. Birds fed the high energy diet also displayed a higher percentage of fat and lower percentage of protein at first egg than did the birds fed the low energy diet. Coefficients of variation for weight of protein and fat-free mass at first egg were 9.1 and 7.9%, respectively, compared to 24.4% for grams of fat at first egg; protein and fat-free masses appeared to be relatively constant at first egg. Linear regressions suggested a strong relationship between body composition and body weight both at 20 wk of age and first egg. Plasma luteinizing hormone levels were unaffected by diet. Key words: Broiler breeder, body composition, body weight, sexual maturity, energy intake