Effects of heat acclimation on energy metabolism of juvenile Larimichthys crocea under temperature stress
Large yellow croaker(Larimichthys crocea)is an important marine economic fish,with a national annual total production of 2.58 × 105t in 2022.It is highly sensitive to environmental temperature changes,and the mass mortality of this species was observed in aquaculture,leading to significant economic losses for farmers.Based on the hormic priming concept,organisms that are pre-acclimated to a mild stress may be able to improve resistance to subsequent higher levels of the same or different stressors.In order to investigate the effects of heat acclimation on the energy metabolism of juvenile Larimichthys crocea under temperature stresses,the fish was pre-exposed to 18.5 ℃ and 24 ℃ for 7 d,and subsequently exposed to heat stress(31±0.5 ℃)and cold stress(9±0.5 ℃)for another 24 h.And the fish that were not acclimated to high temperature could be divided into control group,high-temperature group(HT group),and low-temperature group(LT group).The fish acclimated to high temperature could be divided into heat acclimation plus high-temperature stress group(TA-HT group)and heat acclimation plus low-temperature stress group(TA-LT group).Liver samples were taken after 6,12,24 h of stress to determine the content of adenosine triphosphate(ATP),activities and gene expressions of energy metabolism-related enzymes such as ATP synthase(F-ATP),pyruvate kinase(PK),succinate dehydrogenase(SDH),malate dehydrogenase(MDH),and adenosine 5'-monophosphate(AMP)-activated protein kinaseα subunit(AMPKα).The results showed that compared with the control group,HT group significantly increased PK activity and decreased MDH activity at 6,12,24 h(P＜0.05),indicating that the fish mainly obtained energy by glycolysis.Compared with HT group,TA-HT group remarkably enhanced PK,SDH,MDH activities at 6,12,24 h,reduced ATP content at 12,24 h(P＜0.05),indicating that heat acclimation simultaneously accelerated the adaptability of fish to high-temperature stress,leading to a decrease in the body's energy demand.Compared with the control group,LT group significantly increased MDH activity at 6,12,24 h,and ATP content at 6 h,and reduced SDH activity at 6,12 h(P＜0.05),indicating that the fish mainly satisfied the increased energy demand by enhancing glycolysis during the initial stage of low-temperature stress.Compared with LT group,TA-LT group remarkably enhanced ATP content,SDH and PK activities at 6,12,24 h(P＜0.05),indicating that heat acclimation improved energy metabolism efficiency of juvenile Larimichthys crocea under low-temperature stress.AMPK α mRNA level was positively correlated with the gene expression levels of energy metabolism,indicating that AMPKα was involved in the regulation of energy-expressing genes.In conclusion,the study showed that heat domestication reduced the energy demand of Larimichthys crocea under high-temperature stress,and improved their energy metabolism efficiency under low-temperature stress.The results of this study can help to reveal the mechanism of the effect of heat acclimation on energy metabolism in Larimichthys crocea under temperature stress,and provide a theoretical basis for water temperature regulation in the healthy culture of Larimichthys crocea.
Larimichthys croceahigh-temperature stresslow temperature stressenergy metabolismheat acclimation
万方数据
维普
