光照强度对三疣梭子蟹呼吸代谢的影响

Effects of light intensity on the respiratory metabolism of swimming crab(Portunus trituberculatus)

在实验室条件下，研究了光照强度（0，200，800，1500，3500lx）对三疣梭子蟹耗氧率、排氨率、肌肉中乳酸含量、血淋巴能源物质及己糖激酶（HK）、丙酮酸激酶（PK）、琥珀酸脱氢酶（SDH）和乳酸脱氢酶（LDH）4种呼吸代谢酶活力的影响。结果发现，5种光照强度下，三疣梭子蟹的耗氧率和排氨率均有显著差异，200—1500lx下，蟹的耗氧率显著高于0和3500lx处理组（P〈0．05）；1500lx下，蟹的排氨率显著低于其他处理组（P〈0．05）；光照强度对三疣梭子蟹血淋巴中的总蛋白含量产生显著影响（P〈0．05），但对氧氮比和血淋巴中的其他能源物质未产生显著影响（P〉0．05）；光照强度对三疣梭子蟹的肌肉乳酸含量产生显著影响（P〈0．05），1500lx下，蟹肌肉乳酸含量显著低于其他处理组（P〈0．05），说明该光照强度对蟹机体的胁迫小；1500lx光照下，蟹的HK和PK活力处在较高水平，表明机体糖酵解速率较高，产生更多的能量；SDH的活力处在较高水平，LDH处在较低水平，表明蟹的有氧代谢能力高，有利于蟹的持续运动。研究表明，1500lx光照下，三疣梭子蟹机体受到的胁迫小，整体代谢水平较高，是工厂化养殖较为理想的光照参数。

Indoor experiments were conducted to investigate the effect of constant light intensity on physiology and ecology characteristics of swimming crab （Portunus trituberculatus ）. The oxygen consumption rate （ OCR）, ammonia excretion rate （ AER）, O： N ratio, lactic acid （ LD ）, energetic contents in hemolymph and respiratory enzyme activities including hexokinase （ HK ）, pyruvate kinase （ PK ）, succinate dehydrogenase （SDH）and lactate dehydrogenase（LDH） were tested in five constant light intensity treatments （0,200,800,1 500,3 500 Ix）. The main results were as follows： 1. Light intensity influenced the OCR and AER significantly （P 〈 0. 05）. The oxygen consumption rate of the crab under 200 - 1 500 lx was significantly higher than those of the crab under 0 Ix and 3 500 lx（P 〈 0.05）. The ammonia excretion rate of the crab under 1 500 lx was significantly lower than others （ P 〈 0.05 ）. 2. Light intensity influenced total protein, but did not influence other energetic contents and O： N ratio significantly （P 〉 0.05 ）. Our results suggest that protein is used preferentially as energy source. 3. Marked differences were found in LD （P 〈 0.05）. The LD in muscle of the crab under 1 500 lx was lowest. 4. Different light intensity influenced different respiratory enzymes differently. Under 1 500 Ix, the activity of HK and PK were at a high level. Glycolysis went faster and produced more energy. The activity of SDH was at a high level, while LDH was low. Aerobic metabolism was at a higher level, providing more energy for a continuous motion of crab The results revealed that light intensity affected respiratory metabolism, and the crab at 1 500 lx had higher metabolism while under less stress. So about 1 500 lx may be the better illumination condition of the crab culture industry.