Application of Bacillus amyloliquefaciens as probiotic for Litopenaeus vannamei (Boone, 1931) cultivated in a biofloc system

Abstract

[EN] Probiotics can improve growth, survival and resistance to pathogenic organisms of the
\ncultivated species in aquaculture systems with water recirculation. However, their
\npossible benefits on biofloc systems have been less studied. In this study, the benefits
\nof Bacillus amyloliquefaciens bacterium, on a biofloc culture of Litopenaeus vannamei
\nwere evaluated. B. amyloliquefaciens was applied as dissolved in water. To our
\nknowledge, no previous assays on biofloc systems have been published, and on
\nrecirculation systems it has only been tested mixed with feed. The objective of the
\npresent study was to evaluate the effect of B. amyloliquefaciens on water quality,
\ngrowth parameters and the immune system of shrimp. Three concentrations of probiotic
\nwere tested in triplicate (9.48 × 104
\n, 1.90 × 105
\n, and 3.79 × 105 cfu ml
\n-1
\n) and were
\ncompared with the control (without probiotics). Water quality parameters such as
\nnutrients and suspended solids were monitored. In L. vannamei, growth, survival and
\ntheir immune system parameters (total protein concentration, cell number with
\napoptosis and percentage of granular and hyaline hemocytes) were studied. The results
\nshowed that the application of B. amyloliquefaciens did not produce significant
\ndifferences in water quality or shrimp growth. However, it showed significant
\nimprovements in the immune system. As compared with the control treatment, an
\nincrease in the total protein concentration and granular hemocytes, and a decrease in the
\ncell number with apoptosis in the hempolymph were observed. Thus, we can conclude
\nthat B. amyloliquefaciens provides greater resistance to shrimp against the attack of
\npathogens in biofloc systems.