The effects of dietary supplementation with marine picoalga Picochlorum maculatum MACC3 biomass on growth, digestive enzyme activity, gut microbiome composition, immunity, and pigmentation of Silverado guppies, Poecilia reticulata

This study evaluated the potential benefits of dietary supplementation with chitosan-flocculated biomass of the marine picoalga Picochlorum maculatum MACC3 on the growth, digestive performance, gut microbiome composition, immune response, and pigmentation of juvenile Silverado guppies, Poecilia reticulata. Two groups were established, namely, a control group, without supplementation, and a treatment group supplemented with the algal biomass. Next-generation sequencing-based analysis of the gut microbiome revealed a higher abundance of beneficial bacterial taxa in the treatment group. The supplementation positively modulated the gut microbial structure, which corresponded with enhanced growth, increased digestive enzyme activities, improved immune responses, and intensified pigmentation in the guppies.