Humic acid as a microbial control agent during the incubation of rainbow trout (Oncorhynchus mykiss) eggs

This study investigated the effect of humic acid on survival and as a treatment to reduce fungal and bacterial infections to increase survival during the incubation of rainbow trout (Oncorhynchus mykiss) eggs. Humic acid, an aqueous extract of oxidized lignite, was added to water entering both stacked tray and jar type incubators at a dosage rate of 0.005 mg/L from fertilization until hatching and resulted in increased survival and reduced abundance of pathogens. These findings support the topical treatments of humic acid may be considered as an a potential alternative treatment to treat prevent fungal infections and reduce mortality during incubation of rainbow trout eggs.