Update on the use of yeast in shrimp aquaculture: a minireview

Growth in shrimp farming has shown an expansion of rearing farms and intensification of production methods, which have affected shrimp health, growth and survival and environmental integrity of the coastal areas, making the long-term viability of this farming industry doubtful. This industry demands alternative strategies to improve shrimp production, enhance disease resistance and take good care of the environment. Yeasts (live cell, total cell, or their active by-products) confer a benefit to the host by providing nutrition and protection against pathogens. This review summarizes the current knowledge of yeast species on: (i) shrimp aquaculture; (ii) shrimp nutrition; (iii) shrimp immunity; (iv) water and environment. Yeasts are used as alternative feed ingredients in aquaculture because of their nutritional value. Some products, such as b-glucans, chitin, nucleic acids, mannan oligosaccharides, b-carotene, B-complex, torulene, and torularhodin have been used in shrimp diets, showing direct effect on shrimp growth. Amylases, chitinases, phytases, and proteases are used to enhance gut maturity and digestive enzyme activity in shrimp larvae. The immune and antioxidant proprieties of yeasts have an important role as probiotics and immunostimulants to enhance shrimp resistance against common viral and bacterial diseases. Yeast bioactive products, such as glucans, nucleotides, polysaccharides, carotenoid pigments, lipids, proteins, and vitamins, activate the immune response directly or improve intestinal microbiota, specially glucans, which enhance shrimp circulating hemocytes (THC), phagocytosis, encapsulation, ProPO activity and melanization. Different yeast species, such as Debaryomyces sp., Candida sp., Rhodosporidium sp., Saccharomyces sp., and Yarrowia sp. have recently gained popularity as beneficial candidates in farmed organisms to maintain health conditions and well-being of different aquatic animals, including rearing shrimp. In addition, this study condensed current knowledge of the ability of yeasts to sustain the performance of marine shrimp and provide information for future research and development of yeast application in aquaculture.