The objective of this study was to evaluate the effect of different supplementation levels of Rhodocyclus gelatinosus biomass on the performance and pigmentation of broilers. Cobb broilers were raised in pens and were fed a sorghum-based diet until 35 days of age. At the 36th day of age, ninety-six birds were randomly distributed to four treatments consisting of experimental diets with different supplementation levels of Rhodocyclus gelatinosus biomass (0, 75, 150 and 300 ppm) added to the finisher basal diet, which were given for seven days. A completely randomized experimental design was used, with four treatments, four replicates and six broilers per parcel. Birds and diets were weighed at the 36th and at the 42nd day of age for performance analysis. There was no significant effect on broiler feed intake. Significant differences in weight gain and feed conversion were seen between the control group and the groups supplemented with 75 and 150 ppm. The treatment with the highest supplementation level and the control group had best weight gain and feed conversion. Color analysis showed that R. gelatinosus biomass supplementation resulted in more yellow breast skin and increased darkening and color purity in breast and thigh meat of broilers, but had no effect on lightness or color purity of breast and thigh skins

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Nutritionists need to make commercial decisions about the optimal nutrient content broiler feeds. In order to demonstrate that broiler prices may influence dietary nutrient density, this study developed quadratic feed intake and weight gain equations, according to broiler sex and feeding phase, to be applied in a nonlinear feed formulation model. Four hundred and eighty Cobb broilers were allotted to a completely randomized experimental with six treatments, each with four replicates of 10 birds each, from 1 to 56 days old. Treatments consisted of diets containing 2800, 2900, 3000, 3100, 3200, or 3300 kcal metabolizable energy (ME)/kg and constant nutrient to ME ratio. A nonlinear version of the PPFR feed formulation software (http://www.fmva.unesp.br/ ppfr) was developed with the objective of optimizing energy density and bird performance. According to the results, when the models are applied in the PPFR nonlinear spreadsheet, the most favorable nutrient density content is defined by mathematical models, as optimized by the Excel Solver tool by means of cost/benefit comparisons and as a function of rearing phase (starter, grower, and finisher) and sex. This contradicts the recommendations of genetic company manuals and published requirement tables, whose goal is to maximize weight gain and do not necessarily guarantee maximum economic efficiency.

Pesq. Vet. Bras. 34(5):409-414, maio 2014 409 RESUMO.-A composição de ácidos graxos da dieta pode influenciar o desempenho produtivo e o sistema imune de frangos de corte. O objetivo deste estudo foi avaliar o efeito do consumo de óleos ricos em ácidos graxos poli--insaturados ômega-6 (PUFAs n-6) e ômega-3 (PUFAs n-3) sobre o desempenho e a resposta imunológica de frangos de corte frente a um desafio antigênico. Foram comparadas dietas formuladas com 7% de óleo de soja (OS), linhaça (OL) ou sardinha (OP), fornecidas a 240 frangos da linhaFontes de óleo na dieta e sua influência no desempenho e na imunidade de frangos de corte