Effect of two commercial probiotic products on population growth of rotifer Brachionus rotundiformis Tschugunoff

The application of probiotics has varying effects on rotifer culture. These effects can either be directly on their growth and reproduction or indirectly by affecting the culture environment. The role played by specific probiotic candidates is still indistinct and further research is required to ascertain their significance in rotifer culture. In this study, euryhaline rotifer Brachionus rotundiformis (SS-type) was used to evaluate the effect of two commercial probiotic products on rotifer density, reproductive parameters and unionized ammonia concentration for a twelve-day culture period. To estimate these parameters, rotifers were cultured in glass bottles containing dilute sterilized sea water with the following five diet treatments: Nannochloropsis oculata (control), Igsign (PB1), Toaraze Aqua (PB2) or the combination of N. oculata with either PB1 or PB2. The rotifer density was significantly affected by the addition of probiotic. N. oculata + PB2 treatment resulted in higher rotifer density and specific growth rate compared to the control treatment. Mixis induction was unaffected by N. oculata + PB2 while it was repressed by N. oculata + PB1. Ammonia concentration was not significantly affected with the addition of probiotics. These results indicate that probiotics have synergetic effects with microalgae diet that resulted in the highest rotifer densities.