This study was carried out to evaluate the effect of a multi-carbohydrase complex (MCC) rich in xylanase (Xyl) and arabinofuranosidase (Abf) on overall broiler feed digestibility in broilers. Energy utilization and digestibility of dry matter (DM), organic matter (OM), protein, starch, fat, and insoluble and soluble fibers were measured using the mass-balance method. The experiment was carried out on 120 broilers (3-week-old chickens). Broilers were distributed over 8 treatments to evaluate the effect of the dietary arabinoxylan content and nutrient density with and without MCC (Rovabio® Advance). The graded content of arabinoxylan (AX) was obtained using different raw materials (wheat, rye, barley, and dried distillers' wheat). Diet-energy density was modified with added fat. Measurements indicated that nutrient density and AX content had a significant effect on most digestibility parameters. Apparent metabolizable energy (AME) was significantly increased (265 kcal kg-1) by MCC. The addition of MCC also resulted in significant improvement in the digestibility of all evaluated nutrients, with average improvements of 3.0, 3.3, 3.2, 3.0, 6.2, 2.9, 5.8, and 3.8% units for DM, OM, protein, starch, fat, insoluble and soluble fibers, and energy utilization, respectively. The interaction between MCC and diet composition was significant for the digestibility of OM, fat, protein, and energy. Nutrient digestibility and diet AME were negatively correlated with AX content (P < 0.001). However, the addition of MCC resulted in a reduction of this negative effect (P < 0.001). The AME of diets with and without the addition of MCC were successfully predicted by the diet digestible nutrient (i.e., starch, protein, fat, insoluble and soluble fibers) content with and without MCC (R2 = 0.87; RSD = 78 kcal kg-1). This study confirms that the presence of AX in wheat-based diets and wheat-based diets with other cereals and cereal by-products reduces nutrient digestibility in broiler chickens. Furthermore, the dietary addition of MCC, which is rich in Xyn and Abf, reduced deleterious effect of fiber and improved overall nutrient digestibility in broiler diets.

We sought to estimate the nutrient load in the waste released into aquatic environments based on the feeding of Nile tilapia (Oreochromis niloticus, L.) reared in cages that were installed in artificial reservoirs. For the calculation, an analysis of the chemical composition of commercial feeds intended for this species in their various stages of production was conducted (N = 130). We combined this information with a meta-analysis of published data from commercial producers in Brazil about expected feed intake, feed conversion and other animal production indices, and body composition. With these data, it was possible to estimate the load. We estimated that 18% of the feed given to the animals is not consumed and is lost in the aquatic environment. The calculated average digestibility was 71.97% for the organic matter in the diet, 84.06% for protein and 54.40% for phosphorus. The estimated nutrient deposition efficiency, with respect to what was actually consumed by the tilapia, was 26.39% for organic matter, 43.25% for protein and 34.07% for phosphorus. The total nutrient load in the waste per tonne of biomass of produced tilapias was estimated to be 1040.63 kg of organic matter, 44.95 kg of nitrogen and 14.26 kg of phosphorus, representing 78%, 65% and 72% of the respective nutrient amounts supplied by the feed. The information obtained in this study serves as a reference for predicting the potential impact of tilapia farming in reservoirs and to establish scientific parameters for the planning of this activity.

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This study evaluates the composition and nutritional content of feeds for the commercial production of Nile tilapia (Oreochromis niloticus L.) in Brazil. The feeds were assessed from a nutritional standpoint and as potential polluting agents of aquatic environments. The nutritional contents of each feed were calculated by considering the nutritional contributions of its ingredients based on reference tables. These contents were compared to the nutritional recommendations for O. niloticus. Altogether, 130 feeds were analysed, including 32 meant for fingerlings, 30 meant for juveniles, 38 meant for the growth stage and 30 meant for the termination stage. The overall digestibility of the feeds in terms of dry matter utilization was estimated to be 68.5%. Phosphorus was the nutrient with the lowest mean digestibility (51.2%), while protein had the highest mean digestibility (86.6%). Calcium and phosphorus levels exceeded their recommended values by 256.2% and 31.3%, respectively. The ratios of methionine, methionine plus cysteine, threonine and tryptophan to lysine were below their recommended values. The indigestible contents of nitrogen and phosphorus were 6.96 (±2.57) and 7.35 (±1.77) g kg−1, respectively. The information obtained here provides a reference for estimating the productive and polluting potential of feeds used in the production of Nile tilapia.

A study with 2,400 broilers was carried out to compare the effect of the use of mannanoligosaccharides, Saccharomyces cerevisiae cell wall or growth promoter (Olaquindox) in the diet on broiler. Diets were based on corn and soybean meal. A completely randomized experimental design was used, and the obtained data were evaluated by analysis of variance and test of Tukey at a level of 5%. The following parameters were measured: feed intake, daily weight gain, feed conversion ratio, and mortality. It was concluded that the effect of the inclusion of mannanoligosaccharides in the diet on the studied parameters was significantly higher as compared to the inclusion of cell wall or to the control diet, but the effect was not different as compared to the inclusion of growth promoter