维生素C对降温胁迫下大菱鲆生理生化指标及其肉质的影响

Effects of Vitamin C Pretreatment on Physiology, Biochemistry, and Meat Quality of Scophthalmus maximus Under Cold Stress

【目的】为缓解大菱鲆(Scophthalmus maximus)在降温过程中的应激反应,提高肌肉品质,研究水体中添加维生素C对大菱鲆降温胁迫下生理生化指标及肌肉品质的影响。【方法】首先,将大菱鲆分别放入含0、25、50、100 mg·L^(-1)维生素C溶液处理12 h,然后经制冷循环水系统降温至3℃,无水保活0、12、24、36、48、60、72 h,观察其存活率并筛选最适维生素C浓度;其次,以最适浓度维生素C处理大菱鲆12 h后,进行降温至18、13、8、3℃,分别在4个温度点取样测定白细胞、肾上腺素、皮质醇等生理生化以及肌肉质构指标。【结果】50mg·L^(-1)维生素C溶液处理的大菱鲆无水保活72 h存活率最高,为40.0%。维生素C处理的大菱鲆血液白细胞、红细胞、血红蛋白和血小板浓度均显著高于未处理组(P<0.05);降温过程中,血清肾上腺素、皮质醇、总蛋白等指标含量呈上升趋势,而血清血糖、肝脏肝糖原、肌肉pH呈下降趋势,维生素C处理组生理生化指标变化幅度均显著小于对照组(P<0.05);维生素C处理组硬度、弹性、咀嚼性等指标明显大于对照组(P<0.05)。【结论】经50mg·L^(-1)维生素C处理后,大菱鲆的应激程度及肝肾脏损伤程度得到缓解,能量代谢和肌肉品质方面也更为稳定。表明适当的维生素C处理可在一定程度上缓解降温胁迫对大菱鲆的负面影响。

【Objective】Effects of vitamin C addition in water to improve cold-tolerance of turbot(Scophthalmus maximus)on the physiology,biochemistry,and muscles of the fish in chilling preservation were studied.【Method】Live turbots were kept in water containing 0,25,50,or 100 mg·L^(-1)of vitamin C for 12 h prior to chilling to 3℃by circulating the water through a refrigeration system and holding for 0,12,24,36,48,60,or 72 h out of water to observe the survival rate of the fish and determine the optimal vitamin C concentration for the pretreatment.In water with the optimized vitamin C concentration,turbots were kept for 12 h followed by cooling the water to 18,13,8,and 3℃to measure the physiological and biochemical indexes,such as white blood cells,epinephrine,cortisol,and muscle texture,of the turbots under cold stress.【Result】The turbots kept in water containing 50 mg·L^(-1)vitamin C then chilled to 3℃for 72 h had the highest survival rate at 40.0%.The white blood cells,red blood cells,hemoglobin,and platelets of the vitamin C-treated fish were significantly higher than those of control(P<0.05).During cooling from 18℃to 3℃,the contents of serum epinephrine,cortisol,and total protein in fish were on an increasing trend,while serum glucose,liver glycogen,and muscle p H decreasing;the physiological and biochemical indexes changed significantly less on the pretreated turbots than control(P<0.05);and the muscle firmness,elasticity,and chewiness of the treatment fish were significantly higher than those of control(P<0.05).【Conclusion】With a 50 mg·L^(-1)vitamin C pretreatment,the negative impacts of cold stress on liver and kidney of the chilled turbots were significantly reduced and the energy metabolism and meat quality of the fish relatively unaffected.