Produção e composição bioquímica de dietas suplementadas com pasta liofilizada de spirulina (Arthrospira sp.) produzida com fins de aqüicultura ornamental

Abstract

The ornamental fish culture represents an important aquaculture sector, under social, environmental and economic aspects. Due to the importance of this activity in the economy, there is a growing interest in studies focused on the nutrition of ornamental fish, aiming to understand and meet their nutritional requirements(energy, protein and amino acids, fatty acids, vitamins and minerals) which is essential to ensure good growth rates and survival. In addition, some compounds such as carotenoids are also used in diets to accentuate the skin pigmentation of fish, however, the cost of including this component is still high In this sense, the use of cyanobacteria can be an alternative to produce better quality diets and that result in lower costs in fish production, since it can promote improvements in digestibility, physiological activity, resistance to stress and diseases, as well as in fish color patterns. Thus, the aim of the present study was to analyze the proximate composition of diets prepared with different levels of inclusion of Spirulina sp. for possible use in aquaculture. Spirulina biomass was produced during 30 days in the modified medium of Jourdan under uncontrolled growing conditions, concentrated in a creamer and then lyophilized. In order to characterize the nutritional composition, such as proteins, lipids, ash, dry matter and moisture, physical-chemical tests of cyanobacteria, pure commercial feed, and in three mixtures of the feed with cyanobacterium, in different proportions were performed. The analyzes were performed in the following proportions (D1) 100% commercial feed; (D2) 25% Spirulina and 75% feed; (D3) 50% Spirulina and 50% feed; (D4) 75% Spirulina and 25% ration e; (D5) 100% lyophilized Spirulina. To determine the proximate composition of the diets, analyzes of proteins, lipids, ash, dry matter and moisture were performed. The levels of protein, lipid and dry matter increased as Spirulina was incorporated into the feed, with the highest levels found in D4, with 47.76%, 5.9% and 86.55%, respectively, followed by D3 (44.45%, 4.15% and 84.15, respectively) and D2 (43.30%, 2.54% and 83.70% respectively). However, there was a decrease in ash and moisture content with a higher concentration of Spirulina, with the highest levels in D1 with 14,37% e 17,80%, respectively, followed by D2, (12.90% and 16.30%, respectively), D3 (10.97% and 15.85%, respectively) and D4 (5.90% and 13.45%, respectively). In conclusion, the commercial feed supplemented with freeze-dried Spirulina has a good protein energetic potential and should be tested in ornamental fish, aiming to evaluate the nutritional factors and color enhancement.