不同降温速率休眠的加州鲈无水保活品质比较

Comparison of Dormancy at Different Cooling Rates on the Survival of Micropterus salmoides without Water

为了研究不同降温速率休眠对加州鲈无水保活的影响,按照1、3、5℃/h降温速率将暂养水温为10~13℃鱼样降至临界温度0℃至其休眠,3℃保活,分别保活12、14、16 h后,测定该过程加州鲈血液生化指标和肌肉品质的变化,以期获得最优的降温速率提高存活率。结果表明:3℃/h降温,3℃保活效果最好,保活16 h后复苏率达85.75%,复苏率明显高于其他两实验组;随保活时间延长3个降温速率处理组加州鲈血液中皮质醇、谷草转氨酶、丙二醛、尿素氮、乳酸含均会显著升高(p<0.05),鳃Na+/K+-ATPase、白蛋白含量会显著降低(p<0.05),保活16 h以上指标升高或降低值基本为对照组的1~2倍;与对照组相比,粗蛋白含量、全质构指标中硬度、胶黏性、咀嚼性等肌肉指标随保活时间延长会显著降低(p<0.05)指标,以上指标3℃/h降温组减小值显著低于其他两实验组(p<0.05)。综上所述,3℃/h降温保活对鱼肝脏和肾脏影响较小,既可保证运输较长时间的存活率,也能保证该过程鱼的肌肉品质变化较小。

In order to study the effect of different cooling rates on the survival of Micropterus salmoides without water, the temperature for temporary culture water(10~13 ℃) was reduced, at a cooling rate of 1, 3 or 5 ℃/h, to the critical temperature(0 ℃) to make the fish go dormant, and the fish was kept alive at 3 ℃ for 12, 14 or 16 hours, respectively. Then, the changes of the blood biochemical indices and muscle quality of Micropterus salmoides were determined during this process, to obtain the optimal cooling rate and improve the survival rate. The results showed that a cooling rate of 3 ℃/h along with the temperature for keep-alive at 3 ℃ was the most effective, and the rate of resuscitation from dormancy and after 16-h keep-alive reached 85.75%, which was significantly higher than those of the other two groups;With the extension of keep-alive time, the contents of cortisol, aspartate aminotransferase, malondialdehyde, urea nitrogen and lactate in the blood of the three cooling-treated groups increased significantly(p<0.05), whilst the contents of Na+/K+-ATPase and serum albumin in the gills decreased significantly(p<0.05). The increases or decreases of the above indices for the group after 16-h keep-alive were 1~2 times those of the control group. Compared with the control, the content of crude protein and the muscular texture indices such as hardness, adhesiveness and chewiness were significantly reduced with the extension of keepalive time(p<0.05). The decreases in the above indices of the 3 ℃/h cooling group were significantly lower than those of the other two experimental groups(p<0.05). In summary, cooling at 3 ℃/h for the keep-alive process had relatively little effect on the liver and kidneys of the fish, which can not only guarantee the survival rate of fish subjected to long distance transport, but also ensure least changes in muscle quality of fish during this process.