A 51-Week Egg Production Assessment with White Leghorn Hens Fed on a 400 kcal AMEn/kg Range (2,850 to 2,550)

Energy is a key determinant of feed intake regulation, nutrient utilization, and egg production in laying hens, but the long-term effects of gradual reductions in dietary metabolizable energy remain poorly understood. This study evaluated the impacts of graded decreases in apparent metabolizable energy corrected for nitrogen (AMEn; 2,850, 2,750, 2,650, and 2,550 kcal/kg) on performance and egg quality of Bovans White hens from 25 to 76 weeks of age. Ninety-six hens were allocated to a completely randomized design with four treatments and 12 replicates of two birds each. Data were analyzed using SAS 9.4 (p<0.05). Progressive AMEn reductions had significant effects on performance, with linear decreases in body weight, egg weight, egg mass, and daily energy intake, accompanied by compensatory increases in feed intake. Egg production and feed conversion ratio showed quadratic responses, with optimal values estimated at 2,733 and 2,842 kcal/kg, respectively. Lower AMEn diets also reduced yolk, albumen, and shell weights, although eggshell thickness increased. Overall, hens on the lowest AMEn diet mobilized body reserves to maintain egg output, leading to body weight loss and reduced laying persistency. These findings demonstrate that dietary AMEn from 2,733-2,750 kcal/kg supports optimal production and egg quality, while further reductions compromise long-term performance.