Evaluation of Thalassiosira weissflogii in Litopenaeus vannamei (BOONE, 1931) larval rearing.

Abstract

The objective of this work was to establish the effects of the microalgae Thalassiosira weissflogii in different densities added to experimental L. vannamei larval rearing, as well as assess its use in commercial-scale production. To evaluate the algal densities, were tested three treatments (0.5, 1 and 2 x 104 cells/mL) in experimental conditions. In the commercial-scale larval rearing was compared the use of T. weissflogii with Chaetoceros muelleri as regard to shrimp metamorphosis, final survival and final weight. The results showed that larvae fed with 2 x 104 cells/mL presented low survival and the culture water became highly concentrated with nutrients and total bacteria counts when compared to treatments 0.5, 1 x 104 cells/mL (p < 0.05), which no statistically significant differences were observed in both treatments (p > 0.05) for analyzed parameters. No significant differences were observed in the parameters tested between microalgae species in the commercial-scale larval rearing (p > 0.05). Results demonstrate that T. weissflogii at a density of 2 x 104 cells/mL can be detrimental to shrimp larval rearing due to decay in water quality caused by the introduction of high microalga inoculum, which generates accumulation of nutrients and increase of total bacteria. The use of T. weissflogii showed good results and can be adopted in commercial-scale of the L. vannamei larval rearing.