Replacement of fish meal and oil with vegetable meal and oil in diets used in the fattening phase of white shrimp Litopenaeus vannamei, in biofloc (BFT) systems
Fishmeal and fish oil are the main protein and lipid sources in aquaculture diets. However, the price of fishmeal and fish oil has remained high in recent years. The use of fish meal and oil, and the possible products for their replacement, in diets for shrimp is a subject of extensive research, directed to the search for protein and lipid ingredients, with availability, that do not affect the zootechnical development of animals . This experiment aimed to evaluate the effect of replacing fish meal and fish oil with soy protein and soy oil concentrate on growth, survival, and proximal analysis of shrimp (Litopenaeus vannamei) produced in biofloc (BFT) systems. The experiment was carried out at the Marine Aquaculture Station (EMA) of the Federal University of Rio Grande (FURG).Five diets were formulated, isoproteic and isoenergetic, with different levels of substitution of fish flour and fish oil for soy protein concentrate and soy oil, with the treatments designated as: 0% (without substitution, control diet), 25%, 50%, 75% and 100%. The diets were made to contain approximately 35% crude protein, 8% lipids and 4200 Kcal / Kg of crude energy. The experiment was conducted in a water recirculation system over a period of 35 days, with juveniles of L. vannamei with an initial weight of (3.47 ± 0.19g). No significant differences were found between treatments up to 75% substitution for the variables of specific growth rate, weight gain, weekly weight gain, feed conversion rate and survival. On the other hand,the 100% substitution treatment had lower final weight and final biomass when compared to the other treatments. The present result suggests that in diets for shrimp raised in a biofloc system, fish meal and oil can be replaced by up to 75% with soy protein concentrate and soy oil, without harming the development of animals, showing to be an economical and friendly alternative with the environment.