Avaliação aminoacídica de concentrados proteicos vegetais alternativos na dieta de peixes

Abstract

The objective of this study was to evaluate various alternative vegetable protein sources to replace soybean meal (traditional protein source) on the performance and chemical composition of catfish (Rhamdia quelen) and its influence on the coloration of the fillets. For this, we conducted an experiment lasting 45 days in thermoregulated water recirculation with biological filter (biofilter). For this study, we used 20 experimental units with a capacity of 90L each, where 400 fish were kept. We evaluated four diets with different protein sources, as follows: control diet with soybean meal-based protein; CL: diet containing protein crambe meal concentrate + protein linseed meal concentrate; CLGM: composed crambe meal protein concentrate + linseed meal protein concentrate + cassava leaf protein concentrate + sunflower meal protein concentrate and GM: protein concentrate consisting of sunflower meal + protein cassava leaf concentrate. Each treatment consisted of five repetitions. Juvenile catfish had 11.5±4.99 cm and an initial weight of 10.35±5.5 g. The diet was provided three times a day (8:00, 12:00 and 17:00) and water analysis was performed weekly. At the end of the experiment blood samples were collected for determination of blood parameters (total protein, albumin, triglycerides, total cholesterol and glucose). We also evaluated growth parameters (weight, condition factor, specific growth rate, daily weight gain and relative protein efficiency ratio and feed conversion). In addition, we collected two animals per treatment for proximate evaluate of the whole fish and fillet (moisture, crude protein, amino acids, fat and ash and was conducted to evaluate the instrumental coloration of the fillets. At the end of the experiment, significant differences were observed on growth parameters, except for the condition factor. The color of the fillets presented statistical differences in all diets analyzed, and the animals fed on GM diets CLGM and had a yellowish color, this may be a factor in choosing the product by the consumer. Based on this study, we concluded that the CL diet showed higher growth compared to diets containing protein concentrate of cassava leaves and sunflower, but it was the highest fat content in whole fish and fillet. The color of the fillets was also affected by protein sources, and treatment with protein cassava leaf concentrate resulted in a yellow pigment in the fillets.