Efeitos do uso da tecnologia de bioflocos em camarão marinho infectado experimentalmente pelos vírus da mancha branca e mionecrose infecciosa

Abstract

Shrimp farming on no water exchange systems with bioflocs (BFT) has been shown an alternative to avoid recurrent outbreaks of exotic infectious diseases. Its immunostimulatory role has already been proven in several studies, protecting shrimp by activating several factors present in its immune system and conferring greater resistance to infection. Among these agents, White spot syndrome (WSSV) and Infectious myonecrosis (IMNV) viruses have historically already caused billionaire losses and are still widespread worldwide, including Brazilian shrimp-producing states. Our objective was to evaluate the effect of the use of biofloc technology on experimentally infected marine shrimp by WSSV and IMNV. The animals were divided into three treatments, one with WSSV (W) immersion infection, another with infection by IMNV contaminated tissue (I), a third by the two anterior (IW) and the negative control (C), without viral challenge. At the end of the experiment (day 20), the mortality rate did not differ statistically between any groups. PCR analysis showed no positivity for WSSV in any sample, but there were positive animals for IMNV in treatments C (23.8%) and W (8.7%). However, no animal presented macro and microscopic alterations, indicating the non-development of the infection. These results point to a resistance to infection by the animals, suggesting that bioflocs can act as a barrier against infection.