Summary The effects of exogenous enzymes supplementation on kibble diets for dogs formulated with soybean meal (SBM) as a substitute for poultry by‐product meal (PM) was investigated on nutrient digestibility, fermentation products formation, post‐prandial urea response and selected faecal bacteria counts. Two kibble diets with similar compositions were used in two trials: PM‐based diet (28.9% of PM; soybean hulls as a fibre source) and SBM‐based diet (29.9% of SBM). In experiment 1, the SBM diet was divided into three diets: SBM‐0, without enzyme addition; SBM‐1, covered after extrusion with 7500 U protease/kg and 45 U cellulase/kg; and SBM‐2, covered with 15 000 U protease/kg and 90 U cellulase/kg. In experiment 2, the SBM diet was divided into three diets: SBM‐0; SBM‐1, covered with 140 U protease/kg; 8 U cellulase/kg, 800 U pectinase/kg, 60 U phytase/kg, 40 U betaglucanase/kg and 20 U xylanase/kg; and SMB‐2, covered with 700 U protease/kg, 40 U cellulase/kg, 4000 U pectinase/kg, 300 U phytase/kg, 200 U betaglucanase/kg and 100 U xylanase/kg. Each experiment followed a block design with six dogs per diet. Data were submitted to analysis of variance and means compared by orthogonal and polynomial contrasts (p < 0.05). In both experiments, nutrients and energy digestibility did not differ between diets (p > 0.05). SBM consumption resulted in increased faecal moisture and production (p < 0.05), without effect on faecal score. Higher concentration of propionate, acetate and lactate, and lower ammonia and pH were found in the faeces of dogs fed SBM (p < 0.05). Higher post‐prandial urea was verified in dogs fed SBM (p < 0.05). In experiment 2, the addition of enzymes increased faecal concentration of propionate, acetate and total short‐chain fatty acid (p < 0.05) and tended to reduce post‐prandial urea concentration (p = 0.06). Although with similar digestibility, SBM shows a worse utilization of absorbed amino acids than the PM. Soybean oligosaccharides can beneficially change gut fermentation product formation. Enzymes can increase the gut fermentation activity and improve the SBM proteic value.

a b s t r a c tSugarcane juice is a common beverage in many Brazilian cities. At harvesting season most sugarcane plantation is burnt and this procedure has been shown as an important source of PAHs emission. In the present study 80 samples of sugarcane juice collected from two Brazilian cities, in two different periods, were analysed for the presence of four PAHs: benz(a)anthracene, benzo(b)fluoranthene, benzo(k)fluoranthene and benzo(a)pyrene. PAHs were detected in 50% of the samples. The samples collected between harvests presented mean sums of PAHs of 0.013 lg/kg and 0.012 lg/kg, while the samples collected during harvest presented mean sums of 0.053 lg/kg and 0.055 lg/kg. A higher concentration and incidence of PAHs in the juices collected in the harvest period was verified, corroborating the burning of the crops as a source of sugarcane juice contamination.

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