Effects of diets containing vegetable protein concentrates on performance and activity of digestive enzymes in silver catfish (Rhamdia quelen)

Abstract

The purpose of study was to evaluate the effect of using protein concentrates crambe and sunflower meal in the diet of silver catfish juveniles, as substitute for animal protein source. A total of 300 silver catfish had been separate in 15 experimental units of 280 L, totaling five treatments with three replications. We evaluated two levels (25% and 50%) replacement of the meat and bone meal by protein concentrates of crambe and sunflower meals. Evaluated growth parameters, biological index and digestive enzymes in fish. There was no statistical difference for mass (g) and standard length (cm), but the fish diet CPFCr-25% had greater total length (cm). No difference in dry matter, crude protein and total protein deposited (calculated). However, there was a higher concentration of ash in the carcass of the animals fed the control diet and CPFCr-50% in relation to diet CPFG- 50%, in addition, higher levels of lipids in fish fed diet CPFG-50%. No significant differences for hepatosomatic index, digestive somatic index and intestinal quotient of animals subjected to different treatments. The activity of digestive enzymes trypsin and chymotrypsin did not change. There was increased activity of acid protease. The quantitative and qualitative increase in protein concentration from this fraction allows the use of bran protein concentrates crambe and sunflower as substitutes for animal protein source.