Efficacy of three marine yeasts (Debaryomyces hansenii S8, Debaryomyces hansenii S100 and Candida tropicalis S186) as feed supplement for Penaeus indicus was estimated in comparison with Saccharomyces cerevisiae MTCC 36, a commercial feed (Higashi Maru Feeds, India) and a control feed. The yeast component of control feed was replaced with Carboxy Methyl Cellulose. Biomass of yeast strains in Malt extract agar incorporated into a standard diet was used to prepare the experimental yeast diets. P. indicus was fed these diets for a period of 28 days and growth parameters were assessed. Among the three marine yeast diets, D. hansenii S8 supported the best bio-growth parameters. Commercial feed was found to be better in efficiency compared to the Baker’s yeast (F36) diet and control diet. Histological examination of the hepatopancreas was carried out in an attempt to evaluate the toxic effects, if any, in shrimps fed yeast diets. The cross section of hepatopancreas tubules of the midgut-gland of shrimps that were fed the control feed was taken as reference for the comparative studies. Unlike earlier reports of adverse effects on intestinal function and an intensified immune response in fishes on fish meal replacement diet, no histopathological alterations indicative of toxic effects could be observed in the shrimps fed yeast diets. The three tested marine yeasts could very well be used as feed supplement in aquaculture as they have desirable qualities and no noticeable histological consequences on the shrimps.

Penaeus indicus, Debaryomyces hansenii, saccharomyces cerevisiae, single cell protein, histolog