Aquaculture industry is continuously interested in a deeper understanding of the impacts of farm practices on targeted species with the aim to improve and adjust its sustainable development. It is well known that intestinal microbiota has strong interactions with numerous physiological processes and it composition fluctuates depending on various parameters, including the exposure to antibiotics, which can lead to rapid emergence of resistant bacteria threating global human health.
A first 45-days feeding trials was performed in a Chilean fresh water system on Oncorhynchus mykiss (3 replicates/group) ). Starting with a 15-days of antibiotic treatment with florfenicol added to the diet and following with a 30-days of marine probiotics consortium encapsulated in algae (marine synbiotic) feed supplementation.
A second 60-days feeding trials was performed in a Chilean salted water system on Oncorhynchus mykiss (3 replicates/group). Starting with a 30-days supplementation of marine synbiotic, following with an antibiotic treatment with oxytetracycline by injection and ending with a 30-days feed supplementation of marine symbiotics.
For both trial, evolution of microbiote composition (metabarcoding) after antibiotic treatment and at the end of the 30-days of marine symbiotics feed supplementation period was analyzed and compared to a control group fed with a conventional feed underwent the same approach and antibiotic treatment.
Both studies demonstrated that antibiotic treatment led to significant dysbiosis, characterized by marked alterations in gut microbial diversity and composition. Asignificantly higher amount of γ-Proteobacteria, including potentially pathogenic genus,was observed in the control group. We observed an increase of Bacterioides genus in the marine synbiotic group, well know as a biomarker of resistance to antibiotic-induced stress. Dietary supplementation with marine symbiotics after antibiotic treatment shown a strong and positive modulation on the intestinal microbiota contributing to its recovery.
Marine symbiotic demonstrate a promising and sustainable approach to improve fish health and management facing varios well known challenges.
ORAL PRESENTATION