Adaptive metabolic responses in a thermostabilized environment: Transgenerational trade-off implications from tropical tilapia.

ABSTRACT

Relatively warm environments caused by global warming enhance the productivity of aquaculture activities in tropical/subtropical regions; however, the intermittent cold stress (ICS) caused by negative Arctic Oscillation can still result in major economic losses. In contrast to endotherms, ectothermic fishes experience ambient temperature as an abiotic factor that is central to performance and survival. Therefore, the occurrence of extreme temperatures caused by climate change has ignited a surge of scientific interest from ecologists, economists and physiologists. In this study, we test the transgenerational effects of rearing cold-experienced (CE) and cold-naïve (CN) strains of tropical tilapia. Our results show that compared to CN tilapia, the CE strain preferentially converts carbohydrates into lipids in liver at a regular temperature of 27 °C. Besides, at a low temperature of 22 °C, the CE strain exhibits a broader aerobic scope than CN fish, and their metabolite profile suggests a metabolic shift towards the utilization of glutamate derivatives. Therefore, in response to thermal perturbations, this transgenerational metabolic adjustment provides evidence into the adaptive trade-off mechanisms in tropical fish. Nevertheless, global warming may result in less thermal variation each year, and the stabilized ambient temperature may cause tropical tilapia to gradually exhibit lower energy deposits in liver. In addition to those habitants in cold and temperate regions, a lack of cold exposure to multiple generations of fish may decrease the native cold-tolerance traits of subtropical/tropical organisms; this notion has not been previously explored in terms of the biological effects under anthropogenic climate change.