Use of different Saccharomyces cerevisiae biotic forms as immune-modulator and growth promoter for Oreochromis niloticus challenged with some fish pathogens

The manipulation of intestinal bacterial flora through dietary supplementation of beneficial microbes is a new approach not only from the nutrition point of view but also to overcome the adverse effects of chemotherapeutants and lack of effective vaccines. The current study was performed to assess the role of Saccharomyces cerevisiae as a whole yeast cell (Probiotic), its extract (mannan-oligosaccharide - Prebiotic) and Pre-Probiotic mixture (Synbiotic) as growth promoters and immunostimulants in cultured Oreochromis niloticus (O. niloticus). One hundred fifty-six O. niloticus were divided into four groups fed on Probiotic, Prebiotic, synbiotic and basal diet for two months. Treated fish groups showed significant improvement in growth performance and activation of non-specific cellular/humoral immunological measures together with a relative enhancement of resistance against challenged bacteria. Synbiotic feed additive has proved significant enhancement of fish innate resistance against selected fish pathogens as well as positively increased the growth performance of challenged fish.