The effect on tambaqui fingerlings performance caused by diets containing two different carbohydrate sources was evaluated. Four isoproteic diets with different mango meal concentrations (0, 33, 66 and 100%) replacing cornmeal were tested. The feeding trial lasted 45 days and the feeding rate was 8% of total biomass. 240 tambaqui fingerlings with an initial weight average of 3.66g were distributed in 12 500-liter tanks in a recirculating water system with biofilter. Performance, feed intake, carcass yield, survival, total cholesterol, plasmatic free amino acids, hepatic aspartate aminotransferase(AST), hepatic glycogen and plasma glucose values were evaluated. The results showed that weight gain, daily weight gain, specific growth rate, apparent food consumption, cholesterol, AST and glycogen showed higher values in the treatments with the highest levels of mango meal. Apparent feed conversion, carcass yield, survival and plasma glucose were not affected by the two sources of carbohydrates tested. In conclusion, mango meal used in a practical diet for tambaqui improved growth performance.

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Fish quality is conditioned by several factors, among them desensitization methods applied for fish managing and slaughtering. This research used electric shock at different intensities as a desensitization method for cobia (Rachycentron canadum) slaughtering and evaluated its effects over fish quality during refrigerated storage. The experiment was carried out by numbing the fish with electroshock at the intensities of 100, 150 and 200 Volts, and keeping them in refrigerated storage for 21 days. On the cobia, obtained from a commercial fish farm the following physical, chemical and sensorial characteristics as quality variables were evaluated: dielectric properties, rigor index, pH, texture, color, sensorial evaluation of freshness, ATP and degradation catabolites. The experimental design was a 6×3 factorial (6 times of analysis and 3 electroshock intensities). Significant differences (P<0.05) were observed for the analyzed variables, as a consequence of desensitization treatments and of storage time within each treatment. However, the number of variables affected by the treatment was smaller than the number of variables significantly affected by the storage time, and the interaction time×treatment was highly significant within the results reported. The best results for the parameters tested were obtained when the treatment at 150 volts intensity with the majority of analyzed variables held significant differences (P<0.05) among treatments. It was also concluded that cobia can be conserved in refrigerated storage within seven days after slaughtering using electro-narcosis as a method of desensitization.

The research was carried out with the objective of evaluating different levels of metabolisable energy (3050, 3100, 3150, 3200 and 3250 kcal.kg-1) in the diet of 22-to-42-day-old broilers kept in an environment of thermal stress. Three hundred male chicks weighing 814.7 g initial average weight were distributed in a completely randomised design with five treatments, six replications and ten birds per experimental unit. Feed metabolisable energy levels did not influence (P > 0.05) the performance variables of feed conversion, daily weight gain and daily feed intake in the two phases studied. There were no statistical differences in carcass yields: carcass, chest, thigh, drumstick, heart, wing and back. Differences were observed for the two variables gizzard yield and abdominal fat. A linear increase in the percentage of abdominal fat with an increase in energy levels in the diet was observed. The 3100 kcal.kg-1 level of metabolisable energy is the level indicated by this research because it results in lower abdominal fat content and lower cost per kilo of feed.