Effects of salinity and temperature on reproductivity and fatty acid synthesis in the marine rotifer Brachionus rotundiformis

To examine the effect of salinity and temperature in the marine tropical rotifer Brachionus rotundiformis, we analyzed various in vivo life cycle parameters, fatty acid (FA) composition, and transcriptional levels of elongation of very long-chain fatty acid (Elovl) and fatty acid desaturase (Fad) genes. In the case of life cycle parameters, the reproduction of B. rotundiformis showed the highest fecundity under 5 practical saline unit (PSU) and 30 °C conditions, while the concentrations of total FAs were the highest in 15 PSU and 25 °C-exposed groups, respectively. Besides, changes in culture condition (salinity and temperature) resulted in a decrease in n-3 FAs. Therefore, the correlation between nutrient components and the total yield should be considered to determine the optimal culture conditions for B. rotundiformis. The changes in the transcriptional level of Elovl and Fad genes appear to be involved in the compositional modulations of FA, and in particular, Elovl9b could be suggested as useful biomarker due to its temperature-dependent modulation. •The reproduction of Brachionus rotundiformis showed the best performance in 5 psu and 30 °C.•The concentrations of total fatty acids were the highest in 15 psu and 25 °C group.•Changes in salinity and temperature resulted in a decrease in n-3 FAs.•Elovl9b could be suggested as useful biomarker due to its temperature-dependent modulation.