Fish is considered a meat of important biological value as it represents a valuable source of high quality animal protein; this protein is highly digestible and provides all the essential amino acids required by humans.
The amino acids are the fundamental constituents of the protein, and those that are present in the food are the decisive ones to determine the quality of the protein of the tilapia fillet. Of the 20 existing amino acids, 10 can be synthesized by the body (non-essential), and the rest need to be supplied to the body through the diet (essential).
The Nile gray tilapia is one of the most consumed species in the world, it has characteristics that allow its cultivation in sustainable systems with little or no water exchange, such as the biofloc system, which provides a supplement in the nutrition of cultivated organisms. The biofloc not only provides complementary food in situ , but also produces extracellular enzymes that break down proteins, carbohydrates and other nutritional ingredients, facilitating the digestibility and absorption of the food.
The type of diet offered to farmed fish has a significant effect on the nutrient composition of the meat, and can be adapted to produce a desirable nutrient profile in the farmed species.
To determine the effect of the biofloc system on the
a mino a cid in f illet of the Nile gray tilapia Oreochromis niloticus , an experiment was carried out for 120 days, with two treatments and three repetitions: traditional system (TS) and heterotrophic biofloc system (BFT). Male monosex organisms with initial average weight of 109 ± 39.29 g were used at a stocking density of 100 fish m-3 , fed with extruded pellets with 32% CP . In the present work, nine of the ten essential amino acids were analyzed in the tilapia fillet; where six of these (lysine, threonine, methionine, isoleucine, leucine and phenylalanine) were present in a higher proportion in the tilapia fillet grown in the biofloc system (Table 1 ). With the results obtained in the present work, it is concluded that
t he biofloc system has influence in the protein quality of the meat due to the consume of the microrganisms presents contributes a constant nutritional supplement compared with the traditional system.