饥饿对食蚊鱼和唐鱼幼鱼能量物质消耗及游泳能力的影响

Effects of starvation on the consumption of energy sources and swimming performance in juvenile Gambusia affinis and Tanichthys albonubes

为探究食蚊鱼和唐鱼在遭受饥饿胁迫时其能量物质消耗利用特征以及在游泳能力上的响应在室内(25±1)℃水温下设0(对照组)、10、20、30和40 d5种饥饿时间,研究了饥饿对食蚊鱼和唐鱼幼鱼主要能量物质消耗以及对爆发游泳速度(U_(burst))和临界游泳速度(U_(crit))的影响,旨在从能量代谢和游泳行为角度探讨食蚊鱼和唐鱼幼鱼应对饥饿胁迫的策略及其种间差异.结果表明:饥饿前(0 d对照组),食蚊鱼糖原和脂肪含量均显著小于唐鱼,蛋白质含量却与唐鱼无显著差异,而无论何种游泳速度,食蚊鱼均显著小于唐鱼.经历不同饥饿时间后,两种鱼糖原含量均随饥饿时间增加呈显著幂函数曲线下降趋势,并在饥饿10d时接近于0,而脂肪和蛋白质含量均随饥饿时间呈显著线性下降.与唐鱼相比,食蚊鱼脂肪-饥饿时间线性方程斜率显著降低,但蛋白质-饥饿时间方程斜率却显著增加.饥饿40 d后,食蚊鱼和唐鱼能量物质消耗率均显示为糖原>脂肪>蛋白质;但从能量物质的绝对消耗量来看,食蚊鱼表现为蛋白质>脂肪>糖原,而唐鱼则是脂肪>蛋白质>糖原.而无论何种试验鱼,其U_(burst)和U_(crit)均随饥饿时间增加呈显著线性下降,且U_(burst)-饥饿时间线性方程斜率均显著小于U_(crit)-饥饿时间方程.与唐鱼相比,食蚊鱼U_(burst)-饥饿时间线性方程斜率无显著变化,但U_(crit)-饥饿时间线性方程斜率却显著降低.结果表明,饥饿胁迫下2种鱼的能量物质消耗利用特征与游泳能力变化密切相关.相比唐鱼,食蚊鱼虽然整体上能量储备较少,游泳能力较低,但在饥饿期间却主要利用储存量更大的蛋白质供能,饥饿后脂肪含量下降幅度小于唐鱼,其U_(crit)变化比唐鱼更加稳定,这从一定程度上表明其具有更强的耐饥饿潜力,为适应营养匮乏的溪流生境提供了有利条件.

To explore the consumption of energy sources and swimming performance of juvenile Gambusia affinis and Tanichthys albonubes after starvation,contents of glycogen,lipid and protein,burst swimming speeds（Uburst）,and critical swimming speeds（Ucrit） at different starvation times（0,10,20,30 and 40 days） were evaluated.The results showed that,at 0 day,contents of glycogen and lipid were significantly lower in G.affinis than those in T.albonubes,whereas no significant difference in content of protein between two experimental fish was found.Swimming speeds in G.affinis were significantly lower than those in T.albonubes for all swimming performances.After different starvation scenarios,content of glycogen both in G.affinis and T.albonubes decreased significantly in power function trend with starvation time and were close to zero after starvation for 10 days,whereas the contents of lipid and protein were linearly significantly decreased.The slope of line regression equation between content of lipid and starvation time in G.affinis was significantly lower than that in T.albonubes,whereas there was a significantly higher slope of line equation between content of protein and starvation time in G.affinis.40 days later,the consumption rate of glycogen both in G.affinis and T.albonubes were significantly higher than that of lipid,while the consumption rate of protein was the least.Consumption amounts of glycogen in all experimental fish were the least,G.affinis consumed more protein than lipid,and T.albonubes consumed more lipid than protein.Uburst and Ucrit decreased significantly linearly with starvation time for all experimental fish.Slope of linear equation between Uburst and starvation time was not significantly different between G.affinis and T.albonubes.However,the straight slope between Ucrit and starvation time was significantly lower in G.affinis than that in T.albonubes.These findings indicated that there was close relationship between the consumption of energy sources and swimming performance in starvation.Although the store amounts of energy sources and swimming performance were lower in G.affinis than those in T.albonubes,G.affinis mainly used protein during starvation.The result of more stable lipid content and Ucrit in G.affinis in starvation compared with that in T.albonubes indicated that G.affinis had a fair endurance to starvation,which helped them to adapt to the poor nutrition environment in stream habitat.