Broussonetia kazinoki as a Feed Additive Enhances Disease Resistance against Streptococcus parauberis in Paralichthys olivaceus

Abstract

We report the effect of Broussonetia kazinoki as a feed additive on disease resistance in olive flounder Paralichthys olivaceus, against Streptococcus parauberis. The cumulative mortalities were lower in fish fed with diets supplemented with 1.0% and 2.0% than in those fed with 0% and 0.1% diets. Phagocytic, complement and lysozyme activities were significantly enhanced by 0.1%, 1.0% and 2.0% B. kazinoki diets. Respiratory burst activity was significantly enhanced by 1.0% and 2.0% diets. This study suggests that diets supplemented with 1.0% and 2.0% B. kazinoki enhance the immune parameters concerning resistance against S. parauberis infection in P. olivaceus.