Antimicrobial peptides from fish: beyond the fight against pathogens

Abstract Fish antimicrobial peptides ( AMP s) are small peptides whose actions have great implications in the innate immune response of teleost fish, being considered critical as the first line of defence against a wide spectrum of pathogens. Antibiotics have been widely used in aquaculture, resulting in bacterial resistance. The potential of AMPs as alternative to antibiotics makes them a very interesting tool as they represent lower‐risk peptides to develop resistances, or even in the fight against other pathogens such as viruses. Beyond their antimicrobial function, fish AMP s possess several relevant but little‐known characteristics and capabilities such as host‐defence peptides, antioxidants, active compounds of immunogenic drugs and as adjuvants. Moreover, their antitumour properties make them potential drugs to be used in oncological treatments in human subjects. Novel methodologies as clustered regularly interspaced short palindromic repeats associated proteins system ( CRISPR ‐Cas), or even their use as nutraceutics, seem to be promising instruments to enlarge the functions of fish AMP s. This review discusses these new methodologies, as well as the latest research on fish AMP functions, newly discovered properties of AMP s and their future applications in both the aquaculture industry and human health care.