Dietary Saccharomyces cerevisiae improves survival after thermal and osmotic challenge during sexual reversal of postlarval Nile Tilapia

Objective This study aimed to evaluate the stress resistance and growth performance of postlarval Nile Tilapia Oreochromis niloticus that were fed a diet supplemented with the yeast Saccharomyces cerevisiae as a probiotic. Methods Two groups were established in triplicate: fish that were given a diet supplemented with probiotic and a control group that received a diet without probiotic. Two‐hundred larvae were randomly distributed into each of six experimental units. Fish were fed six times daily. After 20 days, growth performance was determined, including survival, final weight, specific growth rate, feed conversion ratio, and effectiveness of sexual reversal. From these fish, 30 fingerlings (0.25 ± 0.02 g [mean ± SD]) per experimental unit were removed and used to perform stress tests (n = 180), with 10 fingerlings being subjected to three stressors (i.e., transport, osmotic shock, and thermal shock). Result Fish that were fed the probiotic diet showed improved performance in final weight (16.6%) and survival (15.1%), as well as higher resistance to thermal (102.3%) and osmotic (27.5%) challenges, compared to control fish. Conclusion Saccharomyces cerevisiae improved growth performance and survival and had no effect on the rate of masculinization. Impact statement Yeast improves resistance to cold heat stress. Yeast increases resistance to osmotic challenge.