Valor nutricional do resíduo da indústria sucro-alcooleira para frangos de corte

Abstract

Two studies were conducted in order to determine the different yeast sugar cane’s energetic and digestive values, as well as generate equations of prediction for broilers at different ages according to the chemical composition. Four yeasts were collected and analyzed regarding their physical and chemical composition, and then four digestibility assays in four experimental phases were realized: post-hatch, initial, growth I and growth II. The experimental designs were completely randomized with five treatments and six repetitions. The treatments were constituted of a reference diet (corn and soybean meal) and four test diets with the replacement of 30% of reference diet by the yeasts. The percentage composition of dry matter, crude protein, ether extract, ash, neutral detergent fiber, gross energy and yeast’s geometric mean diameter (μm) were, respectively: 90.71, 17.11, 0.37, 7.54, 6.86, and 661 to 4214 yeast 1; 88.84, 18.05, 0.44, 8.05, 7.65, and 695 to 4268 yeast 2; 89.99, 14.94, 0.49, 9.1, 3.02, and 933 to 4011 yeast 3; and 90.47, 21.12, 0.30, 9.0, 12.13, and 616 to 4095 yeast 4. The values of apparent and corrected apparent metabolizable energy (kcal / kg) were: yeast 1 (2090, 1953), yeast 2 (1764, 1537), yeast 3 (2223, 2069) and yeast 4 (1674, 1566) for the post-hatch period; yeast 1 (1229, 1070), yeast 2 (1802, 1670), yeast 3 (1285, 1197) and yeast 4 (1571, 1527) for the initial period; yeast 1 (924, 803), yeast 2 (961, 940), yeast 3 (879, 698) and yeast 4 (986, 944) for the growth I period; yeast 1 (800, 785), yeast 2 (1181, 1154), yeast 3 (1422, 1408), yeast 4 (779, 781) for the growth II period, respectively. The amino acids compositions and yeast protein digestibility were determined. There were variations in amino acid composition of the studied yeasts, however the 2 and 4 yeasts had a higher percentage of amino acids. The crude protein digestibility coefficients values and digestible protein values were: yeast 1 (72.59, 12.42), yeast 2 (81.22, 14.66), yeast 3 (76.74, 11.46), yeast 4 (78.46, 16.57) for the post-hatch period; yeast 1 (66.80, 11.43), yeast 2 (78.28, 14.13), yeast 3 (68.11, 10.17), yeast 4 (66.66, 14.07) for the initial phase period; yeast 1 (63.09, 10.79), yeast 2 (74.75, 13.49), yeast 3 (63.28, 9.45), yeast 4 (62.61, 13.22) for the growth I period; yeast 1 (61.40, 10.50), yeast 2 (71.21, 12.85), yeast 3 (62.64, 9.35), yeast 4 (61.89, 13.07) for the growth II period. There was an effect of age and chemical composition in the values of yeasts’ metabolizable energy and protein digestibility, thus it was generated 8 equations of prediction, with or without the use of intercept to estimate the energetic and digestive values for broilers.