ABSTRACT: The objective of this study was to evaluate the effect of different levels of crude cottonseed oil in isoenergetic diets, with or without supplementation of ferrous sulfate, on performance variables, relative weight of organs, and blood parameters of broilers, and on the economic viability of diets in the periods from 1 to 7 and 1 to 21 days of age. A total of 600 male birds of the Ross line were distributed in a completely randomized design in a (4×2) factorial arrangement with eight treatments (0, 2, 4, and 6% cottonseed oil with and without ferrous sulfate), and five replicates. The following variables were studied: feed intake, weight gain, feed conversion, weight of organs, blood parameters, and yield of carcass and cuts at 21 days. No effects of the levels of cottonseed oil were found on the performance of animals aged 1 to 7 days, or on the relative weights of the organs. In this same period, the weight gain, and the relative weights of heart, liver, and intestine of the animals that received ferrous sulfate were decreased, and feed conversion was worsened. In the period from 1 to 21 days, weight gain increased linearly with the increase in the levels of cottonseed oil. Blood parameters were not influenced by the diets. Crude cottonseed oil can be utilized in diets for broilers in the periods from 1 to 7 and 1 to 21 days of age at up to 6% of inclusion, and supplementation with ferrous sulfate is unnecessary if the differences in metabolization of the cottonseed oil are considered, with and without, it during the diet formulation process.
