Grape by-products as growth promoters for broilers from 1 to 21 days of age/Subprodutos da uva como promotores de crescimento em dietas de frangos de corte de 1 a 21 dias de idade

An experiment was conducted to determine the effects of phenolic compounds from grape by-products (Vitis vinifera) as growth promoters in the diets of broilers between 1 and 21 days of age. Six hundred Ross male chicks were raised from 1 to 21 days of age. The experimental design was completely randomized a 6 x 2 factorial scheme (six diets, inoculated or not inoculated with strains of Escherichia coli), and five repetitions consisting of 10 animals each. Each bird received an isonutritive basal diet consisting of grape by-products or antibiotics as follows: T1-negative control; T2--positive control-0.05% of flavomycin and colistin sulphate; T3--0.04% defatted grape seed extract; T4--0.1% grape seed (WGS); T5--0.47% WGS; and T6--2.35% WGS. Analyzed variables were: weight gain, feed intake, average weight gain, body weight, feed conversion and production efficiency index. Including grape by-products did not influence parameters of rate growth or show any growth promoter activity. Inoculating with E. coli decreased weight gain and body weight. The results did not recommend the use of grape by-product.