Pedro D. M. Dias1, Rafael Félix1, Sara C. Novais1, Adriana P. Januário1, Marco F. L. Lemos1 and Carina Félix1
1MARE – Marine and Environmental Sciences Centre, ESTM, Politécnico de Leiria, Peniche, Portugal
The increase of human population has created the need for intensive food production, being aquaculture one of the solutions used to supply seafood. In Asia, the shrimp farming industry has increased in the last 4 decades. However, the intensive aquaculture is a risk factor for disease outbreaks and consequent mortality of the living stock, leading to elevated economic losses. The Acute Hepatopancreatic Necrosis Disease (AHPND), caused by Vibrio parahaemolyticus, was firstly registered in China in 2009 and spread to Vietnam, Malaysia and Thailand, and is characterized by the hepatopancreas destruction of the animal, causing high percentages of death and major economic losses.
Asparagopsis armata is an invasive seaweed in Portugal with a recognized biotechnological potential for the feed industry. An ethanolic extract from this species already demonstrated activity inhibiting V. parahaemolyticus growth in vitro and reducing AHPND-related death in vivo when a supplemented diet is used to feed the whiteleg shrimp Litopanaeus vannamei. The main goal of this work was to decipher the mechanism of action of this extract regarding its anti-Vibrio activity, through biochemical and molecular analyses, in order to understand effective mechanisms against this disease.
The results showed that at minimal inhibitory concentration (2 mg.mL-1) the mitochondria activity and the biofilm formation decreased with increasing concentrations of extract and time intervals, while extracellular protein content increased in the same conditions. Regarding the real time quantification of genes potentially involved in these mechanisms of action, a global tendency was found, with an increase of gene expression with increasing concentrations of A. armata extract, and is further depicted in this work.