Resíduo do cultivo de cogumelos comestíveis na alimentação de cordeiros confinados.

Abstract

One experiment was carried out to characterize the mushroom cultivation substrate as a function of fungus growth time and three experiments to determine the best level of replacement of Tifton-85 hay by the mushroom cultivation residue in the diet of confined lambs. To characterize the substrate for mushroom cultivation, the substrate was collected at the mushroom factory at seven ages of fungus inoculation, 0, 5, 10, 15, 20, 25 and 30 days, and bromatological analysis was carried out. For the animal experiments, five levels of replacement of Tifton-85 hay by the residue from mushroom cultivation were tested, namely: 0, 25, 50, 75 and 100% based on DM. The first animal experiment was carried out with forty crossbred lambs (Santa Ines × Dorper) with a mean age of four months and mean body weight of 27.8 ± 2.37 kg, to evaluate nutrient intake, performance, of carcass, ingestive behavior and blood parameters. The second experiment was carried out with twenty-five animals, with a mean age of six months and mean body weight of 40.0 ± 3.0 kg, on which the coefficients of digestibility and nitrogen balance were determined, where both were used in a completely randomized design. The third experiment was conducted with five rumen-cannulated adult lambs, 12 months of age and average weight of 42.0 ± 4.0 kg, which were distributed in a 5 × 5 Latin square. Variables were analyzed using the SAS PROC MIXED procedure, with statistical significance set at P ≤ 0.05. The composition of the cultivation substrate is modified as the fungus grows, so that the percentages of DM, EE, NFC reduced, while ash, CP, NDF, ADF and IVDMD increased. Nutrient consumption increased quadratically, mainly due to the smaller particle size and consequent reduction of digesta permanence in the rumen. The digestibility of DM, OM, CP, NDF and TDN reduced, due to the higher proportion of indigestible components, such as ADF and lignin in the highest percentages of residue used. There was greater nitrogen intake, with greater fecal N excretion and a reduction in N excreted in the urine, resulting in greater nitrogen retention, according to the levels evaluated. pH and ammonia nitrogen were not influenced, while the population of protozoa reduced. The performance and carcass characteristics were also not altered with the replacement of hay by residue. Significant variations were observed mainly for the feeding time and rumination time, which reflect the physical characteristics of the diets, especially the particle size. There were no alterations in the blood parameters of the animals fed with residue from mushroom cultivation instead of hay. It is therefore recommended to replace Tifton-85 hay with mushroom growing residue by up to 100%, as it increased N retention, in addition to decreasing the population of protozoa. Although there was maintenance of performance, there was a reduction of soybean meal in the diet, the ingredient with the highest cost.