Efeitos de níveis protéicos e probiótico no desempenho do camarão marinho cultivado em meio heterotrófico

Abstract

This study aimed to evaluate the culture of Litopenaeus vannamei marine shrimp fed with different protein levels diets in heterotrophic systems with and without probiotic addition. It was adopted a completely randomized design with 4 x 2 factorial arrangement, using four dietary protein levels (200, 250, 300 e 350 g Kg-1 CP), as the first factor (P20, P25, P30 and P35), and probiotic addition in the water, as the second factor (P20Pro, P25Pro P30Pro e P35Pro). For this were used 24 fiberglass tanks (800 L working volume), filled with a mixture of 300 liters of seawater (30 g L-1), chlorinated and dechlorinated, and 500 liters of seawater from the before culture. Each tank was stocked with 240 juveniles (300 shrimp m-3) averaging 1.55±0.1 g. Water temperature, dissolved oxygen, pH and salinity were measured daily, while NH3-N, NO2-N, NO3-N, PO4-P and alkalinity were analyzed weekly. There were no significant differences in daily parameters of water quality (temperature, dissolved oxygen, pH and salinity; P>0.05), while the weekly parameters only nitrite was influenced by the protein levels (P<0.05). After 50 days of culture the average shrimp final weight was 7.2±0.4 g (P≥0.05). The interaction of protein levels vs. probiotic addition influenced significantly (P<0.05) the survival (70.6 to 90.0%), final biomass (1,315-2,002 g/m3) and biomas gain (681-1,230 g). In Litopenaeus vannamei intensive culture with the utilization of biofloc as supplemental food it is possible to reduce the protein levels of feed from 35 to 20%, without compromising the shrimp growth performance and water quality of culture.