Desempenho produtivo e composição corporal de juvenis de tilápia do nilo alimentados com feijão, Phaseolus vulgaris L., Extrusado e in natura

Abstract

The aquaculture has great growth worldwide and in Brazil the state of Paraná stands out with the production of Nile tilapia (Oreochromis niloticus). From sustainable aquaculture produc tion with agroecological guidelines, fish farming emerges as a viable economic alternative for family farmers. In this sense, the objective of this study was to evaluate the effect of the inclu sion of beans (Phaseolus vulgaris L.) residue from the processing industry, previously extrud ed and in natura, as an alternative ingredient in organic diet, on the survival, growth and body composition of Nile tilapia juveniles. Five isoprotein and isoenergetic diets were prepared to contain 0, 10 and 20% extruded and in natura beans (control, 10FE, 10FN, 20FE and 20FN, respectively) in a completely randomized design, in triplicate. The diets were prepared with certified organic ingredients and offered for 30 days to tilapia juveniles (0.24±0.05 g) stored (20 fish/experimental unit) in 15 polyethylene tanks (60 L of useful volume), connected to a heated (26 ºC) and salinized (3‰) water recirculation system with individual aeration. At the end of the feeding period, survival and performance variables (weight gain, daily feed intake, feed conversion and specific growth rate) of tilapia juveniles were evaluated. Fish samples were randomly collected at the beginning and end of the experimental period to determine the body composition of the whole fish. Zootechnical performance and survival of Nile tilapia juveniles were significantly influenced by dietary treatments. The inclusion of fresh beans in diets resulted in worsening of all variables analyzed (P<0,05), on the other hand, the results obtained with diets containing extruded beans did not differ from the control (P>0.05). Mois ture, crude protein and hepatosomatic index were not influenced by dietary treatments (P>0.05). However, nile tilapia juveniles fed diets containing fresh beans showed the lowest lipid and highest ash contents (P<0.05). It is concluded that the inclusion of 10% or more of fresh bean meal in the diet is harmful for Nile tilapia juveniles in the initial phase of develop ment, but the extrusion process improves its utilization by fish, allowing inclusion in the diet of up to 20% without impairment in the performance and survival of juveniles of O. niloticus.