Avaliação de rações comerciais para o cultivo super-intesivo de juvenis de Litopenaeus vannamei, com um mínimo de troca de água.

Abstract

The Pacific white shrimp, Litopenaeus vannamei (Boone, 1931), is the only commercially grown crustacean in Brazil. In 2016, its production reached 52,120 tons. with an estimated value of USD255 million. Currently, super-intensive cultivation technologies have been implemented in farms in the Northeast region. The objective of this study was to evaluate 10 commercial rations in two super-intensive juvenile cultures of L. vannamei, operated with a minimum of water exchange, using circular experimental tanks from LANOA / LABOMAR / UFC. The research was carried out in two stages, using 25 circular tanks of 6.37 m3. The first and second stages evaluated five rations (1-5 and 6-10, respectively) at the initial densities of 186 and 282 shrimps / m2 for 81 and 87 days, respectively. The shrimp were stocked with body weight of 1.74 and 1.53 g, respectively. The observed averages for temperature, salinity and pH in the 1st and 2nd stages were: 29.1 °C and 30.6 °C; 36 g / L and 41 g / L; 7.65 and 7.45, respectively. The final survival rate was over 90%, with no significant effect of the type of feed used. The average productivity gain in the 1st crop reached 1.962 ± 173 g / m2 (p> 0.05). In the second stage, rations 6 and 7 resulted in a more significant gain of productivity, of 3.1 kg / m2, compared to rations 8 and 9, with 2.8 kg / m2, and finally the ration 10, with 2, 6 kg / m2. The final body weight of shrimp fed rations 3, 4 and 5 was significantly higher than that of rations 1 and 2. In the 2nd crop, final body weight was higher with ration 6, followed by rations 7, 8, 9 and 10. The increase in density also resulted in slower shrimp growth, from a maximum of 1.13 g / week in the 1st crop to 1.00 g / week in the 2nd crop. Two regression equations were defined to correlate the culture time (t) with shrimp body weight (WG) at densities of 186 and 282 animals / m2: WG = 1.461e(0.027 t), p<0.0001, r2 = 0.816 and WG = 1.562e(0.025 t), p< 0.0001, r2 = 0.839, respectively. By means of the present study it was possible to verify that juveniles of the L. vannamei shrimp present a survival, growth, and adequate alimentary efficiency when cultivated in high density regime, using a minimum of water exchange.