越冬对黄鳝(Monopterus albus)机体生化组成及部分血清生化指标的影响

以初始体重为(118.42±4.38) g的黄鳝(Monopterus albus)为研究对象，研究越冬对黄鳝机体生化组成及部分血清生理生化指标的影响。实验结果显示，与越冬前相比，1) 越冬后黄鳝全鱼、肝脏和肌肉组成显著改变，越冬后鱼体粗脂肪含量显著下降(P<0.05)，鱼体水分和粗灰分含量显著升高(P<0.05)，肝体比和肝糖原含量极显著降低(P<0.01)，肝脏粗脂肪含量显著升高(P<0.05)，肌肉中总氨基酸和必需氨基酸含量极显著升高(P<0.01)，肌肉中饱和脂肪酸含量极显著降低(P<0.01)，多不饱和脂肪酸含量显著升高(P<0.05)；2) 越冬后黄鳝血清甘油三酯、葡萄糖和总蛋白含量以及血清氨基酸发生显著改变，越冬导致黄鳝血清甘油三酯、葡萄糖含量显著降低(P<0.05)，总蛋白含量极显著升高(P<0.01)，黄鳝血清中总氨基酸和必需氨基酸含量显著下降(P<0.05)，但越冬对血清总胆固醇和尿素氮含量、谷草转氨酶和谷丙转氨酶活力无显著影响。上述结果表明，越冬期间黄鳝营养物质消耗以肝糖原和鱼体脂肪为主，越冬后肌肉氨基酸和脂肪酸组成显著改变。

Effects of Overwintering on the Body Biochemical Composition and Serum Biochemical Indices of Rice Field Eel (Monopterus albus)

Temperature is one of the key environmental factors affecting the growth and physiological functions of fish. Both the physical activity and the feeding behavior of fish can be significantly reduced or even stopped at low temperature. In this case, fish may consume stored nutrients to stay alive. Rice field eel Monopterus albus is a subtropical freshwater fish with great commercial values. They are prone to diseases and have a high mortality rate in winter. Previous studies suggested that overwintering could significantly affect the intestinal digestive enzymes, the immune and antioxidant functions (serum catalase and lysozyme), muscles and the liver lipid content of M. albus. However, changes in nutrients and physiological adaption during overwintering have been unclear. In this study, we conducted a 124-day experiment to investigate effects of overwintering on the body biochemical composition and partial serum biochemical indices of M. albus with the initial average body weight of (118.42±4.38) g. Results showed that after overwintering: 1) The compositions of the whole body, the liver and muscles of M. albus were significantly affected. The body crude lipid decreased compared to that before overwintering (P<0.05), whereas the body moisture and body crude ash were increased (P<0.05). The hepatosomatic ratio and the content of the liver glycogen were dramatically reduced (P<0.01), but the liver crude lipid was significantly increased (P<0.05). In muscles, the level of saturated fatty acids dropped (P<0.01), the content of polyunsaturated fatty acids rose (P<0.05), and the total amino acids and essential amino acids were markedly increased (P<0.01). 2) The serum triglycerides, glucose, total amino acids and essential amino acids became lower than those before overwintering (P<0.05), and the level of total serum proteins was greatly increased (P<0.01). However, there were no differences in the total cholesterol, the blood urea nitrogen, the aspartate transaminase and the alanine aminotransferase before and after overwintering (P>0.05). In conclusion, M. albus may consume the liver glycogen and body lipids to maintain life activities during overwintering, which consequently changes the compositions of amino acids and fatty acids in the muscle.