Effects of dietary supplementation with probiotic live yeast Debaryomyces hansenii on the immune and antioxidant systems of leopard grouper Mycteroperca rosacea infected with Aeromonas hydrophila

Abstract

Two trials were conducted to determine the e⁄cacy of ¢sh fed live yeast Debaryomyces hansenii strain CBS 8339 on immune and antioxidant systems in leopard grouper Mycteroperca rosacea infected with Aeromonas hydrophila .J uveniles (12� 0.5 g) were fed with a control diet or a D. hansenii-supplemented diet (10 6 colony-forming units per gram) for 5 weeks. The live weight of ¢sh was registered on a weekly basis. After 4 weeks, ¢sh from each treatment were immunocompromised with pathogenic A. hydrophila and further fed for1week in order to evaluate the eiect on immunological and antioxidant parameters. Generally, the results showed enhanced growth performance in ¢sh fed the diet containing yeast compared with the control. Addition of live yeast had no signi¢cant eiect on the immunological parameters after 4 weeks of feeding. However, post infection with A. hydrophila ¢sh fed the yeast-supplemented diet resulted in a signi¢cant increase in the levels of plasmatic immunoglobulin M. Superoxide dismutase and catalase (CAT) activities were signi¢cantly higher in the yeast group. In this ¢sh, CAT and heat shock protein 70 genes were up-regulated before and after infection of A. hydrophila. The present study is the ¢rst one reporting that yeast (D. hansenii) can enhance immunity and resistance against A. hydrophila.