Search

ABSTRACT Cassava by-products are abundant and largely unused in familiy agro-industries in the Amazon region, where slow-growing broilers are commonly raised. Thus the incorporation of cassava by-products in broiler feed may provide starch enrichment for better zootechnical performance. We evaluated the use of cassava residues instead of corn in the diet of slow-growing broilers. We determined the chemical composition of cassava scrapings (CS) and cassava starch residue (CSR), and tested the digestibility of the residues in 192 broilers and three treatments: inclusion of 30 g kg-1 CS or CSR and a control without residue, with eight replicates of eight broilers each. Digestibility was assessed through collection of total excreta from 19 to 22 days of age. Apparent and corrected metabolizable energy, and apparent digestibility coefficients of dry matter, crude protein and crude energy were significantly higher for CSR than CS. Therefore, only CSR was used in a performance experiment using 324 broilers 30 to 90 days old, distributed in four treatments (0; 6.8; 13.4 and 20 g kg-1 CSR in feed) with nine replicates of nine broilers each. There was no significant difference among treatments in weight gain, feed intake, yield of carcass, breast and viscera, meat color, luminosity, pH, shear force, cooking-weight loss and drip loss. As there was a significant reduction in feed conversion and thigh and drumstick yield for 20 g kg-1, we suggest the incorporation of CSR up to 13.4 g kg-1.

This study evaluated the use of dehydrated guava by-products (DGBP) in the feed of slow-growing broilers as a substitute for corn. A total of 324 one-day-old broiler Naked Neck from a slow-growing lineage were used. At 30 days of age, the broilers were distributed in an entirely randomized experimental design consisting of four treatments with nine replicates and nine birds in each replicate. The treatments were differentiated by varying concentrations of DGBP (0, 5, 10, and 15%) in the feed. Performance data [feed intake, weight gain, and feed conversion ratio (FCR)] were evaluated from 30 to 60 days and 61 to 84 days of age. At 84 days of age, the broilers were slaughtered; subsequently, the analyses of carcass and organ yield in terms of chemical composition of the breast, thigh and drumstick, and meat quality parameters (coloration, pH, weight loss by cooking and dripping, shear force, and sensory evaluation) were performed. There was no effect of DGBP on the average weight, weight gain, feed consumption, and FCR of the broilers (P > 0.05). However, there was an increasing linear effect (P < 0.05) on the gizzard yield and a quadratic effect on the liver and abdominal fat yield, where treatments with 5 and 10% DGBP obtained the highest yield percentages. There was no effect (P > 0.05) of DGBP addition on chemical composition, pH, shear force, and weight loss by cooking and dripping. A linear increasing effect on coloration (P < 0.05) was found due to dietary DGBP in all the cuts of meat. In addition, a significant difference (p < 0.05) was found in the texture of the breast meat, where the greater the amount of DGBP added, the greater the scores attributed by the tasters. In conclusion, DGBP can be included up to 15% in the diet of slow-growing broilers without altering the production performances, carcass and cut yield, and meat quality parameters. Furthermore, it promoted a reddish coloration of the breast skin and thigh skin of the birds.