Exigência de proteína para frango de crescimento lento até 28 dias.

Abstract

The objective was to evaluate the performance of slow-growing broilers, reared in confinement, submitted to different levels of protein. 1000 male red naked neck broilers of the French lineage were used in a completely randomized design. The treatments were divided in four diets with different levels of digestible protein: 16.5%, 18.0%, 19.5% and 21.0% until the 28 days of age. It was evaluated the performance, and the rate of fat and protein deposition in the carcass. The data were submitted to variance analysis and the results to linear regression. The daily and total weight gain showed quadratic effect (P>0.01) with estimated maximum value above 21%, considering the effects in these variables as trend, because the value is above of the maximum tested. The feed conversion also showed quadratic effect (P<0.01) with estimated value of digestible protein requirement of 19.6%. The protein and fat deposition rate showed quadratic effect (P<0.01). For the rate of protein deposition, the concentration of 21% is the best recommended. For a lower fast deposition in the carcass, it is recommended the protein concentration of 19.5%. And digestible protein level of 19.5% for male red naked neck broilers of the French lineage.