Response of life-history traits, population dynamics, offspring size of Brachionus plicatilis exposure to BTBPE

The novel brominated flame retardant 1, 2-bis (2,4,6 tribromophenoxy) ethane (BTBPE) has been widely used since the mid-1970s and detected in the aquatic environment and organisms; however, little information is available regarding its biotoxicity. In this study, the life-history parameters, transcriptomic regulation, multi-generational offspring size, and population dynamics of rotifers were determined in response to BTBPE (0, 0.01, 1, and 100 μg/L). The results showed that BTBPE (>1 μg/L) significantly increased the pre-reproductive time, shortened both reproduction periods and the lifespan, and decreased the total number of rotifer offspring. Transcriptomic analysis revealed that the expression of key genes involved in the pathways of citrate cycle, 2-oxocarboxylic acid metabolism, carbon metabolism, and propanoate metabolism was affected. Moreover, BTBPE has transgenerational effects on rotifers, the size of the F1 to F5 generations decreased significantly in response to BTBPE. Finally, the population density in the 100 μg/L BTBPE treatment group was significantly reduced by 30 % compared to the control group, suggesting that the population growth of rotifers was inhibited by BTBPE exposure. The findings of this study indicate that BTBPE has effects on the individual reproduction, population growth, offspring quality, and energy metabolism of rotifers. These findings highlighted the potential impacts of BTBPE on dominant zooplankton species, providing useful baseline information for evaluating the potential ecological risk of novel brominated flame retardant.