Archivos de Zootecnia
versión impresa ISSN 0004-0592
SOUZA, K.M.R. et al. Cassava root meal in diets of free-range broiler chickens. Arch. zootec. [online]. 2011, vol.60, n.231, pp.489-499. ISSN 0004-0592. http://dx.doi.org/10.4321/S0004-05922011000300038.
The aim this work was to evaluate cassava root meal inclusion levels in diets of free-range broiler chickens on performance, carcass yield, parts yield and functional properties of the meat. 384 male chickens of ISA S757-N strain (naked neck) were distributed in a completely randomized design with four treatment and four replicates of 24 birds each. The treatments were 0%, 20%, 40% and 60% of FRIM (cassava root meal) in the total ration. The trial period was divided into three rearing phases: initial (1 to 28 days of age), growth (29 to 56 days of age) and fattening (57 to 84 days of age). Final body weight (PF), weight gain (WG), feed intake, feed conversion and liveability were evaluated. At 84th day, carcass, breast, thigh + upper thigh, wing, back and abdominal fat yield were obtained. Breast meat was used to determine the pH, water holding capacity (CRA) and cooking loss (PPC) too. The shank and breast skin color scores were determined by visual comparison. The results were submitted to analysis of variance, analysis of regression and averages were compared by Tukey's test to 5% of probability. The analysis of variance found a significant difference between treatments for BW and WG, only at the phase of 1 to 28 days of age. There was a linear increased in BW and WG when the CRM inclusion level increased in feed. There were no significant differences between the treatments for the variables of carcass yield, cuts yield, pH, CRA and PPC. The use of FRIM in the diets of freerange broiler chickens promoted linear reduction in the shank and breast skin colors with the increase of the inclusion level of this ingredient in the feed. The FRIM can be used in the diets of freerange broiler chickens in the proportion of 60% of total ration without resulting in worst performance, carcass yield, cuts yield and functional properties of the meat, however it promotes shank and breast skin no coloration.
Palabras clave : Color of skin; Meat functional properties; Naked neck; Rearing system; Weight gain; Yield of carcass.