1,3-1-6 ß-glucans enhance tissue regeneration in zebrafish (Danio rerio): Potential advantages for aquaculture applications

High aquacultural rearing density and handling of fish may frequently result in skin or gills wounds, thereby facilitating the onset of secondary infections. The capacity of the zebrafish to regenerate tissues, as well as fins and other organs, makes it an ideal animal model for studying the mechanisms of tissue regeneration. Since macrophages are involved in tissue regeneration, a diet including ß-glucans might positively affect the process through activation of macrophages and other immune pathways. Consequently, the aim of the present study was to investigate the effects of the oral administration of 1,3-1,6 β-glucans on the regeneration process of the caudal fin after its amputation in zebrafish. One hundred twenty zebrafish were randomly distributed into 4 groups with 3 replicates each: an untreated non-amputated group (CNA) and an untreated amputated group (CA) fed a control diet; two treated and amputated groups (MI and MII) fed for 14 days the same diet with the addition of two differently extracted 1,3-1,6 ß-glucans (MacroGard® and Experimental MacroGard®, Biorigin©, Sao Paulo, Brazil). ß-glucans were added to allowed the administration of 12.5 mg kg-1 of fish body weight (0.35 g kg-1 of feed). Results showed that 1,3-1,6 ß-glucans decreased fish mortality rate and enhanced both daily and cumulative regenerated fin area, independent of the specific ß-glucan extraction method used. Based on the mechanisms similarities of the innate immune system and tissue regeneration among different teleost species, these results may likely be extended to species of interest for the aquaculture sector.