急性低温胁迫对四指马鲅幼鱼肝脏、肌肉以及鳃组织结构的影响

The effects of acute low temperature stress on liver, muscle and gill tissues of juvenile Eleutheronema tetradactylum

为探究急性低温胁迫对四指马鲅Eleutheronematetradactylum幼鱼肝脏、肌肉以及鳃组织结构的影响。该研究设置了常温(27±0.5℃)组、20℃组以及15℃组共三个温度梯度进行试验,以常温组作为对照,在试验进行的2 h、6 h以及12 h分别采集肝脏、肌肉以及鳃样品进行观察和测定。结果显示:随着低温处理时间的延长, 20℃组的肝脏细胞空泡结构呈增多,细胞核偏离,染色变浅趋势;肌纤维出现弯曲现象,肌纤维之间与内部均出现较大间隙;线粒体丰富细胞数目增多,鳃小片末端轻微的膨大到鳃小片整体水肿且严重弯曲,血管以及血窦内出现大量的红细胞,部分鳃小片因红细胞过多而涨破;同时,15℃组肝脏细胞排列混乱,肝板结构不清晰,细胞核溶解,肝脏整体失去固有形态。肌纤维间隙增大,部分断裂直至肌纤维之间与内部均严重开裂,部分肌纤维溶解并暴露出细胞核。鳃小片表皮出现轻微的脱落,少部分鳃小片胀大到其吸水涨破,鳃小片基本形态不可见。该研究结果为优化四指马鲅养殖生产温控管理措施,提高越冬成活率提供参考资料。

In order to explore the effects of acute low temperature stress on liver,muscle and gill tissues of juvenile Eleutheronema tetradactylum,three test groups,control group(27±0.5℃),20℃group and 15℃group,were set up in this study.The liver tissue,muscle tissue,and gill tissue were sampled at 2 h,6 h and 12 h when low temperature stress occurred to make slices.Results showed that with the time prolonging,the liver cells in 20℃group performance as vesicles structure was increased;nucleus was deviated and the staining became shallow.The muscle fibers were bending,and there was a large gap between the muscle fibers and the interior.The number of mitochondria rich cells was increased,and slight swelling symptom occurred at the end of the gill lamellae,until to final,the gill lamellae became overall edema and severely bending.A large number of red blood cells were appeared in sinus and blood vessels,besides,part of gill lamellae was burst because of too many red cells.Meanwhile,the liver cells in 15℃group performance as the liver cells chaotic arrangement,the liver plate structure was not clear,the cell nucleus dissolved,and the whole liver lost its inherent form.The gap between muscle fibers increased,and some of them ruptured until the muscle fibers were severely cracked.Some muscle fibers dissolved and the nucleus was exposed.The epidermis of the lamellae of the gill appeared slight shedding.A few of lamellae was swollen,finally,it was burst because of water absorption,and the basic form of lamellae was not visible.Results of this study provide reference for overwintering management of juvenile E.tetradactylum and improving survival rate in winter.