Influence of Dietary Energy and Antibiotic on Performance,Egg Solids,and Egg Quality in Bovans White and Dekalb White Hens

A 4 × 2 × 2 factorial experiment with 4 dietary energy levels (2,776, 2,820, 2,864, and 2,908 kcal/kg) and 2 strains (Bovans White and Dekalb White) with and without Tylosin was conducted to determine the influence of dietary energy and antibiotic on performance, egg solids, and egg quality. The experiment lasted 10 wk. Bovans White hens (n = 768) and Dekalb White hens (n = 768) at 55 wk of age were randomly divided into 16 treatments (8 replicates of 12 birds per treatment). Bovans hens had significantly greater egg production and significantly lower egg weight, egg-specific gravity, and shell weight than Dekalb hens. Increasing dietary energy by the addition of poultry oil had no significant effect on performance, egg solids, or eggshell quality. An ideal dietary energy level for optimal performance could not be determined. There can be no fixed ideal dietary energy level for optimal profits, due to varying feed ingredient and egg price. Although Tylosin supplementation had no effect on performance or egg solids, Tylosin significantly reduced dirty eggs, resulting in a positive effect on egg quality.