Glucose protects the pacific white shrimp Litopenaeus vannamei against Vibrio alginolyticus by inhibiting biofilm formation.

Biofilms not only enhance the colonization of bacteria on the surface of the host but also increase the pathogenicity of bacteria. In this study, five carbon sources were determined to inhibit the biofilm formation of Vibrio alginolyticus R9 to different levels. Among the tested carbon sources, 0.5 % glucose showed an inhibitory effect on biofilm formation but a promotion in the dispersal of mature biofilms of V. alginolyticus R9, both of which led to significant loss in biofilm mass. It was further shown that glucose inhibited the biofilm formation of V. alginolyticus R9 by inhibiting autoaggregation and promoted the dispersal of mature biofilms by inhibiting isocitrate lyase (aceA) activity. The addition of glucose in diets reduced intestinal tissue damage caused by V. alginolyticus R9 via inhibiting 83.8 % V. alginolyticus R9 colonized in the intestine of the shrimp Litopenaeus vannamei, with a relative percent of survival of 47.4 % and improved pathological symptom. However, the relative abundance of Vibrio in the intestine of L. vannamei decreased 13.4 % in the presence of glucose. It could be concluded that glucose alleviated infection symptoms of L. vannamei mainly by inhibiting the biofilm formation of V. alginolyticus R9 on the intestinal epithelium rather than reducing the relative abundance of Vibrio in the intestine. This is the first study to demonstrate that glucose can inhibit biofilm formation and promote the biofilm cell dispersal of V. alginolyticus, which offers a new strategy for the control of Vibrio infections in aquaculture.