Therapeutic modulation of fish gut microbiota, a feasible strategy for aquaculture?

The intestinal epithelium of fish is the major absorptive barrier for nutrients assisted by a large number of microbes. These are known as resident microbiota or gut microbiota, which has a symbiotic relationship with the host, playing key roles in pathogen protection, nutritional, endocrine, neural, and physiological functions. Dysbiosis is an impairment in the balance of the commensal communities forming the gut microbiota. This imbalance is caused by several factors with physiological consequences for the host and subsequent reduced growth and higher mortality rates. Therapeutic modulation strategies of the gut microbiota have been successfully used in higher vertebrate models; however, these procedures can also be adapted for their application to fish and other aquatic animals. Strategies such as probiotics, prebiotics, synbiotics, paraprobiotics, and postbiotics, as well as other emerging strategies, are discussed as potential therapeutic approaches for treating or avoiding dysbiosis in fish.