Effect of Canary native plant extracts on bacterial growth for relevant pathogens in aquaculture

Abstract

Introduction: Antibiotics are currently the most effective way to control outbreaks of disease in aquaculture, however have disadvantages, increasing questions about their use, such as bacterial resistance, environmental care and consequences for human health. Immunostimulants, prebiotics and probiotics are actually the more promising alternatives to antibiotics. The plant extract are gaining special interest in order to know antimicrobial properties. Canary plants are used for their medicinal properties from the first inhabitants of the Canary Islands. Methodology: The main aim of this work looks for analyzing the in vitro antimicrobial qualities of plant native to the islands against relevant pathogens for continental and marine aquaculture (Vibrio anguillarum, Photobacterium damselae subsp. piscicida, Streptococcus iniae, Yersinia ruckeri, Aeromonas salmonicida and Vibrio harveyi). Antimicrobial susceptibility testing EUCAST disk diffusion method was used, adapting the medium used to our bacteria requirements. Ethanolic plant extracts used belong to several genera of Family Compositae (Daisy family): Agallopappus dichotomus subsp. dichotomus, A. dichotomus subsp. latifolius, Gonospermum fruticosum, Lugoa revoluta, Nauplius stenophyllus,Tanacetum oshanahanii, T. ptarmicaeflorum, Viera laevigata. Results and Conclusions: Canary plant extracts used in this study have showed antimicrobial activity against relevant strains of pathogens for aquaculture. Concentrations of the plant extracts used (mainly 100 μg/ml) resulted appropriate to test antimicrobial effect, against bacterial strains used, regardless the active principle they contain. It is necessary to study in depth, in order to reach more clear and effective results, to evaluate the possibility of using these extracts as prebiotics in aquaculture, which is now real and closer for controlling relevant pathogens.