Antibacterial Activity of Citrus limon Peel Essential Oil and Argania spinosa Oil Against Fish Pathogenic Bacteria

The main objective of the study was the identification of antibacterial activity of lemon (Citrus limon L.) peel essential oil and argan (Argania spinosa L.) oil against fish pathogenic bacteria. Antibacterial activity was determined against six different fish pathogens (Yersinia ruckeri, Aeromonas hydrophila, Listonella anguillarum, Edwarsiella tarda, Citrobacter freundii and Lactococcus garvieae). Essential oil derived from lemon peel and argan oil were applied against the bacteria using the disc diffusion and micro dilution method under in vitro conditions. The disc diffusion results indicated that essential oil of naturally C. limon peel and argan oil significantly inhibited the growth of Y. ruckeri, A. hydrophila, L. anguillarum and C. freundii. Our results suggested that the use of lemon peel essential oil and argan oil induced a stronger antibacterial effect

Evidence of threat to European economy and biodiversity following the introduction of an alien pathogen on the fungal-animal boundary

Recent years have seen a global and rapid resurgence of fungal diseases with direct impact on biodiversity and local extinctions of amphibian, coral, or bat populations. Despite similar evidence of population extinction in European fish populations and the associated risk of food aquaculture due to the emerging rosette agent Sphaerothecum destruens, an emerging infectious eukaryotic intracellular pathogen on the fungal-animal boundary, our understanding of current threats remained limited. Long-term monitoring of population decline for the 8-year post-introduction of the fungal pathogen was coupled with seasonal molecular analyses of the 18S rDNA and histological work of native fish species organs. A phylogenetic relationship between the existing EU and US strains using the ribosomal internal transcribed spacer sequences was also carried out. Here, we provide evidence that this emerging parasite has now been introduced via Pseudorasbora parva to sea bass farms, an industry that represents over 400M(sic) annually in a Mediterranean region that is already economically vulnerable. We also provide for the first time evidence linking S. destruens to disease and severe declines in International Union for Conservation of Nature threatened European endemic freshwater fishes (i.e. 80% to 90 % mortalities). Our findings are thus of major economic and conservation importance