| Resumo: |
Two different studies were conducted in order to develop the present work. In the first, the objective was to determine the values of apparent metabolizable energy (AME) and nitrogen corrected apparent metabolizable energy (AMEn) of coconut meal (CM), cashew nut meal (CNM) and two types of sugar cane yeast (SCY1 and SCY2) for chicks and roosters. Two metabolism trials were developed applying the total collection excreta methodology with chicks (12 days of age) and another with adult roosters (27 weeks of age). For both trials, birds were allotted in a completely randomized design with five treatments and five replicates of eight chicks in the first trial and two roosters in the second. Treatments consisted of a reference-diet and four test-diets containing 40% of each by-product (CM, CNM, SCY1 and SCY2) and 60% of a reference-diet. Values of AME e AMEn (kcal/kg of dry matter) of all by-products studied were higher for roosters than those for chicks. The second experiment was carried out to evaluate the effect of a partial substitution of soybean meal protein (SMP) by coconut meal protein (CMP) and sugar cane yeast 1 protein (SCY1P) in diets containing cashew nut meal (CNM) on broiler performance. For this study, 585 day-old male chicks from Ross line were allotted in a completely randomized design with nine treatments and five repetitions of 13 birds per treatment. Treatments consisted of a control diet and eight diets in which SMP was substituted by CMP and SCY1 at the levels of 5%; 10%; 15% and 20%. According to regression analysis, the substitution of SMP by CMP in levels higher than 5% reduced linearly feed intake (FI), weight gain (WG) and feed conversion (FC) for initial phase. Also, there was a quadratic effect for breast yield as SMP was substituted by CMP up to the level of 11.5%. However, Dunnett’s test showed that the substitution of SMP by CMP did not affect bird performance and carcass yield up to the level of 20% compared to control diet. The substitution of SMP by SCY1P in the initial phase increased FI and FC until the level of 12.5% and reduced WG linearly. Nevertheless, the substitution of SMP by SCY1P up to the level of 20% did not affect bird performance and carcass yield (Dunnett, 5%). According to the economic study, substitution of SMP by both by-products (CMP and SCY1P) in broiler diets is economically viable up to the level of 20%. It can be concluded that in broiler diets containing 20% of CNM, soybean meal protein can be substituted by CMP and SCY1P at the level of 20%. Key Words: metabolizable energy, cashew nut meal, coconut meal, broiler chick, sugar cane yeast |
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