Two trials were conducted to evaluate the energetic value and the optimum level of increasing dietary annatto seed by-product (ASB) levels for broiler chick. In the first trial, sixty Ross male broiler chicks (516 + 8.62 g) were fed ad libitum with a basal diet (BD) and a mixture of BD+30% ASB. The first trial was analyzed as a complete randomized design with five replications of six birds. Feces were collected in the morning and afternoon from age 20 to 25 days. In the second trial, 1,190 Ross male broiler chicks were allocated in boxes of 1.5 m2 , analyzed as a complete randomized design with ten replications of 17 birds. The following treatments were used: 0 (control), 2.5, 5.0, 7.5, 10.0, 12.5, and 15.0% ASB from 1 to 21, 22 to 42, and 43 to 47 days old. ASB diet was formulated to contain 12.12% CP and 2,233 kcal AMEn. The 7.5% ASB treatment increased feed intake from 22 to 42 day old, but decreased feed conversion in overall period (1 to 47 days) in relation to the control treatment. Excluding the 0% ASB treatment of variance analysis, carcass and drums yields and drum weight decreased linearly, whereas drumstick yield was optimized with 9.9% ASB in the diet. According to the performance data, it is recommended to include up to 9.9% ASB in the broilers diet.
alternative feedstuff; nutritive value; performance
