不同温度条件下运动和摄食对细鳞鲑幼鱼代谢模式的影响

Effect of locomotion and feeding on metabolic mode of juvenile lenok,Brachymystax lenok (Pallas) under different water temperatures

为了揭示不同温度条件下运动和摄食对细鳞鲑幼鱼代谢模式的影响,在饱和溶氧(>8.0 mg·L-1)条件下,分别测定了空腹组和摄食组在5个处理温度(4、8、12、16和20℃)下的运动前代谢率(MO2p)、活跃代谢率(MO2a)、代谢范围(MS)、临界游泳速度(UC)以及10个流速水平下的实时游泳代谢率(MR).结果表明:在各个温度条件下,摄食组的MO2p和MO2a均显著高于空腹组(P<0.05),且分别提高了15%和12%(4℃)、47%和23%(8℃)、30%和21%(12℃)、43%和36%(16℃)及8%和7%(20℃);摄食组与空腹组的UC和MS均无显著性差异(P>0.05),但随着温度升高,两组的MS均呈现下降趋势;随流速的增加,各组的游泳代谢率呈先升高后降低的变化规律,且摄食组显著大于空腹组(P<0.05),各组的最大代谢率峰值均出现在低于UC的流速条件下;在细鳞鲑幼鱼的游泳速度接近70%UC的运动过程中,其代谢率不断增大至峰值,随后在游泳速度达到UC的过程中,代谢率呈下降趋势.表明在一定温度范围条件下,细鳞鲑幼鱼的最大代谢率是由运动与摄食共同诱导产生的,在达到最大代谢率峰值的过程中代谢表现为添加模式;之后随游泳代谢率的下降,摄食诱导的代谢率被削减,该过程表现为运动优先代谢模式.

To investigate the effect of locomotion and feeding on the metabolic mode of juvenile lenok, Brachymystax lenok （Pallas） under different water temperatures, the pre-exercise oxygen consumption rate （ MO2p）, active oxygen consumption rate （ MOna ）, metabolic scope （ MS）, criti- cal swimming speed （ Uc ） and swimming metabolic rate of both fasting and fed fish were measured at five temperature levels （4 ℃, 8 ℃, 12 ℃, 16 ℃ and 20 ℃ ） and ten flow velocities with satu- rated dissolved oxygen （ 〉8.0 mg · L-1 ）. The results showed that the MO2p and M02a of the feeding group were significantly higher （P〈0.05） than the fasting group under different temperatures, and the increases in MO2p and MO2a at 4 ℃ , 8 ℃ , 12 ℃, 16 ℃ and 20 ℃ were 15% , 47% , 30% , 43% and 8%, and 12%, 23%, 21%, 36% and 7%, respectively. No significant differences were observed for Uc and MS between the fasting and the feeding groups （ P〉0.05 ）, but the MS showed a trend of decline with increase in water temperature. Swimming metabolic rate of fish was increased with increasing the flow velocity, and further increase of flow velocity resulted in a decline in swimming metabolic rate, and the swimming metabolic rate of the feeding group was significantly higher than that of the fasting group （P〈0.05）. The metabolic rate increased with increasing the swimming speed up to 70% Uc, and then decreased with increasing the swimming speed up to Uc. It was concluded that, under certain temperature, the maximum metabolic rate was induced by exercise and feeding; the maximum and the the metabolic rate exhibited the additive metabolic mode before increasing to reafter, the metabolic rate induced by feeding swimming metabolic rate, exhibiting the locomotion prioritized mode reduced with decreasing the