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In order to evaluate the partial replacement of fish meal by chemical silage of pig by-products in extruded diets to feeding fish, a total of 360 small fish of Clarias gariepinus (10.15 ± 0.01 g initial weight and 11.8 ± 0.01 cm) were used, randomly placed in three treatments with three repetitions, according to one-way model. The treatments were a control diet, with 35 % of fish meal and two experimental, with levels of 10 and 20 % (dry basis) of chemical silage with pig by-products, representing substitution of 28.75 % and 57.14 % of fish meal, respectively. The survival was high in all treatments (100 to 96%). The food and protein supplied per fish were reduced (P <0.05) in 8.64 g and 3.09 g respectively, for 20% of pig by-products with respect to the control. There were significant differences (P <0.001) in growth. In the treatments with 10 and 20 % of chemical silage of pig by-products, the final weights were 7.4 g and 28.33 g lower than in the control, and the length was only statistically reduced 3.26 cm for 20% of chemical silage of pig by-products. The conversion factor was affected at 530 g more of food/kg of live weight, when including 20% of by-product chemical silage, as well as protein efficiency, which decreased with that treatment. The condition factors K were similar for the three evaluated diets. It is concluded that silage can be acceptable up to 10% (dry basis) in extruded diets for Clarias gariepinus and higher levels markedly reduce productive indicators. [ABSTRACT FROM AUTHOR]

In order to evaluate the partial replacement of fish meal by chemical silage of pig by-products in extruded diets to feeding fish, a total of 360 small fish of Clarias gariepinus (10.15 ± 0.01 g initial weight and 11.8 ± 0.01 cm) were used, randomly placed in three treatments with three repetitions, according to one-way model. The treatments were a control diet, with 35% of fish meal and two experimental, with levels of 10 and 20% (dry basis) of chemical silage with pig by-products, representing substitution of 28.75% and 57.14% of fish meal, respectively. The survival was high in all treatments (100 to 96%). The food and protein supplied per fish were reduced (P <0.05) in 8.64 g and 3.09 g respectively, for 20% of pig by-products with respect to the control. There were significant differences (P <0.001) in growth. In the treatments with 10 and 20% of chemical silage of pig by-products, the final weights were 7.4 g and 28.33 g lower than in the control, and the length was only statistically reduced 3.26 cm for 20% of chemical silage of pig by-products. The conversion factor was affected at 530 g more of food/kg of live weight, when including 20% of by-product chemical silage, as well as protein efficiency, which decreased with that treatment. The condition factors K were similar for the three evaluated diets. It is concluded that silage can be acceptable up to 10% (dry basis) in extruded diets for Clarias gariepinus and higher levels markedly reduce productive indicators. [ABSTRACT FROM AUTHOR]

A total of 225 young fish of Clarias gariepinus (10.1+0.01g initial average weight) were randomly distributed in three triplicate treatments according to the simple classification model, with the purpose of evaluating the productive performance of these fishes, by reducing the amount of ration and increase dietary protein levels. The treatments consisted of three diets with 34.7, 39.2 and 43.7% of crude protein added at 8.0, 7.0 and 6.4% of body weight / day so that all fishes received 2.8 g of crude protein / kg live weight /day. The supplied feed did not significantly differ (P> 0.05) between treatments (44.3, 44.9 and 45.3 g/fish). However, significant differences were found in supplied CP (16.1, 18.0 and 20.4 g / fish), the growths (39.4, 47.8 and 59.1 g of average weight) and feed conversion (1.5, 1.2 and 0.9), in favor of increasing dietary protein levels. The economic analysis showed differences in the rations cost (US $ 0,857, 0,977 and 1.088 / kg), but lower amounts in the production of 1kg of live weight (US $ 1,285, 1,172 and 0.979 / kg). It was demonstrated that the reduction of the amount of ration with increase of dietary protein improved the productive performance of Clarias gariepinus with positive economic effect. [ABSTRACT FROM AUTHOR]