Avaliação de proteases ácidas e alcalinas para juvenis de tilápia

Abstract

Nutrition is an essential factor for the development of aquatic organisms, considering that protein is a costly and limiting factor for fish diets. In this context, an alternative is sought to reduce the use of protein in feed. Therefore, the objective of the study was to evaluate the influence of blends of acidic and alkaline proteases FC-TECMAX PRO FC®: on the productive performance of juvenile Nile tilapia. The experiment was conducted at the Aquaculture Studies and Management Group (GEMAq) at UNIOESTE campus Toledo, PR. 400 specimens of Nile tilapia were used, with an average initial weight of 12.57 ± 0.22 g. The animals were distributed in 20 boxes in polyethylene (5 treatments/4 repetitions), totalizing 20 animals per experimental unit and 80 fish per treatment, over a period of 51 days. The diets were formulated with Positive Control (CP) protease inclusion levels: recommended nutritional levels to meet nutritional requirements; Negative control (CN): Depreciated nutritional levels (protease valorization); CN+100; CN+200 and CN+400 of protease. To the Final of experiment were verified you parameters of performance production, fish body indices, analysis of digestive enzyme activity and histology of muscle, liver and intestine. No significant differences were observed in the productive performance of the animals when comparing all treatments, as well as in the bromatological indices of the diets and fish. Regarding enzymatic activity, changes were observed in maltase activity, with the highest activity being 1651.47 (nmol/min/mg of protein) in fish fed with CN + 100 g/t of protease, although it did not contribute to improving production performance. Regarding histological performance, it was observed that CN+200 and CN+400 presented greater height and width of the intestinal villi. In relation to the number of hepatocytes, the best results were found in CP and CN. In this sense, the use of proteases presents in FC-TECMAX PRO FC®: did not contribute to improving the productive performance of juvenile Nile tilapia. The enzymatic variables indicate the need for further studies regarding the metabolism of fish fed with the inclusion of proteases in the diet.