Developing pituitary adenylate cyclase-activating polypeptide into a treatment for microbial infections in fish and shrimp aquaculture

In 2017, aquaculture provided more than 50% of the fish humans consumed. In Cuba, there are plans to double the fish farming industry by 2030. However, aquaculture occurs in uncontrolled ocean and pond water that contains many potential pathogens. Antibiotics are used regularly to prevent and treat bacterial diseases, but resistant strains have arisen, making treatment less effective in this vital food source.

Antimicrobial peptides (chains of amino acids) offer an alternative treatment that is already part of the host immune response. The pituitary adenylate cyclase-activating polypeptide (PACAP) has shown antimicrobial properties in humans, but its activity in aquatic animals has not been well-explored.

This project seeks to characterize and select polypeptides with immunostimulant and antimicrobial activities to protect fish and shrimp against infectious diseases in Canada and Cuba. This will be achieved by assessing the antimicrobial and immunostimulant activity of variants of PACAP with modifications to extend the effective lifespan of the molecule, and then determining the dose and treatment plan most effective in rainbow trout in Canada.

The information obtained from testing and optimizing the use of PACAP as an antimicrobial treatment in Canada will be shared with Cuban scientists to apply to Cuban species, including tilapia, claria, and shrimp. Due to the characteristics of this class of polypeptides, it has the potential to increase animal health and reduce the need for antimicrobials.