Two metabolism assays were carried out in order to evaluate the aparent metabolizable energy (AME) and true metabolizable energy (TME) values of 11 feedstuffs (corn and corn byproducts and of the millet samples) by using the traditional method of excreta collection with growing chickens and the forced feeding method, by using adult cockerels (Sibbald method). In the first assay, 540 male Hubbard chickens fed the experimental diets in four replicates with ten birds in each experimental unit and the basal diet fed to six replicates. In the second assay, each one of 11 feedstuffs was fed to six cockerels, 15 g were fed at 8:00 a.m. and 15 g were fed at 4:00 p.m., after fastening by 24 hours. Simultaneously six cockerels were fasted in order to determine the metabolic and endogenous nitrogen losses. After determination of AMEn and TMEn values, prediction equations were simulated to predict the energetic values of the corn and corn byproducts, based on chemical composition. The AMEn and TMEn of feed evaluated ranged from 1937 to 4108 and from 2246 to 4248 kcal/kg of dry matter, respectively. The results shown that millet should be one alternative feed to corn, with lower energetic value. The prediction equations adjusted with the variables neutral detergent fiber (NDF) or crude fiber (CF) and ash should be used to predict the energetic values of corn and corn byproducts, being AMEn = 4281.6 -- 39.97 -- 72.90ash (R² = 0.96) or EMAn = 4354.8 -- 112.05CF -- 151.74ash (R² = 0.95) and EMVn = 4485.1 -- 34.20NDF -- 83.83ash (R² = 0.94) or 4250.22 -- 136.60CF -- 120.48ash (R² = 0.91).
broiler chickens; cockerels; metabolizable energy; prediction equations; corn; millet
