Metabolizable energy of crude glycerin for broiler chickens at different ages

Abstract

The values of apparent metabolizable energy (AME), the AME corrected for nitrogen retention (AMEn) and their respective metabolization coefficients (CME and CMEn) of crude glycerin were determined utilizing the total excreta collection method with broiler chickens at different ages. A randomized complete design was used, with six treatments, six replications and ten, five and four birds per experimental unit in the periods from 11 to 20 days, from 21 to 30 days and from 31 to 40 days of age, respectively. The test food replaced the reference diet in 0; 3; 6; 9; 12 and 15% and the experimental period lasted ten days, five of which for adaptation and five for total collection. The AME and AMEn values in the phase from 11 to 20 days ranged from 2723 to 3817 and from 2672 to 3666 kcal/kg-1, respectively. In the phase from 21 to 30 days the AME and AMEn values ranged from 3723 to 3982 and from 3555 to 3945 kcal/kg-1, respectively. In the phase from 31 to 40 days the AME and AMEn values ranged from 3029 to 4143 and from 2975 to 4048 kcal/kg-1, respectively. The values of CME and CMEn linearly decreased from 11 to 20 days of age, ranging from 87.39 to 62.90 and 84.41 to 61.53%, respectively. During the phase from 21 to 30 days the coefficients also linearly decreased, ranging from 91.70 to 84.30 for CME and from 90.80 to 81.40% for CMEn. In contrast, during the phase from 31 to 40 days, the coefficients linearly increased, values ranging from 95.39 to 69.76 for CME and from 93.21 to 68.51% for CMEn. The crude glycerin can be used as an energy source in broiler diets, because it has high levels of metabolizable energy. However, the values of AME and AMEn and the metabolization coefficients of crude glycerin vary according to the levels in the reference diet and age of the birds.