冷胁迫诱导休眠方式对虾夷扇贝无水保活期生命特征及营养品质指标的影响

Effects of cold stress-induced dormancy methods on life characteristics and nutritional quality indexes of Patinopecten yessoensis during anhydrous living-preservation

探究虾夷扇贝(Patinopecten yessoensis)保活运输前的最佳诱导休眠方式,可为其保活流通提供理论依据。参考产业实际流通,采用散冰降温和急性降温和梯度降温3种低温诱导休眠方式处理虾夷扇贝,探讨了不同降温休眠方式对虾夷扇贝无水保活期的成活率、生命特征及营养品质的影响。结果表明:梯度降温组在4℃条件下保活3 d后的成活率为93.33%,明显高于急性降温和散冰降温组;在降温休眠过程中,散冰降温和急性降温组由于温度骤变,无法检测到规律的心电图,梯度降温组的心率呈规律性缓慢下降趋势;保活期间,各组扇贝的心率均呈下降趋势,保活3 d后,散冰降温组已无规律心率,梯度降温和急性降温组仍有规律心率;3组降温方式的缩边率和外套膜响应时间均呈逐渐上升的趋势,其中散冰降温和急性降温组的缩边率和外套膜响应时间显著高于梯度降温组,且心率与外套膜响应时间呈负相关关系;水分、粗蛋白、粗脂肪和肌糖原含量均呈下降趋势,其中对肌糖原的消耗最大,梯度降温组相较于其他组在保活期营养成分损失较少,且梯度降温组的闭壳肌在微观组织结构上排列紧密整齐,无明显断裂。研究表明,采用梯度降温诱导扇贝进入休眠或半休眠状态后开始无水保活,有利于提高活体扇贝的成活率,减少其在流通过程中营养成分的损失,进而保持其活力,更有利于其无水保活。

Exploring the best method to induce the dormancy of scallops(Patinopecten yessoensis)before live transport can provide a theoretical basis for their survival and circulation.Referring to the actual industrial circulation,we treated the samples by three methods of natural cooling of crush ice,acute continuous cooling and gradient cooling,so as to explore the effects of different cooling and dormancy methods on the survival rate,life characteristics and nutritional quality of scallops during anhydrous living-preservation.The results show that the survival rate of the gradient cooling group was 93.33%after 3 d of keeping alive at 4℃,significantly higher than that of the acute and natural cooling groups.In the process of cooling dormancy,regular electrocardiogram could not be detected in the natural and acute cooling groups due to the sudden temperature change,and the heart rate in the gradient cooling group showed a regular slow decline.During the live transport,the heart rate in each group showed a decreasing trend.After 3 d of keeping alive,the irregular heart rate in the natural ice cooling group was no longer observed,while the irregular heart rate in the gradient and acute cooling groups was still observed.The edge mantle retraction ratio and the response time of all three cooling groups tended to increase gradually(Those of natural and acute cooling groups were significantly higher than those of gradient cooling groups),and the heart rate was negatively correlated with the response time of the mantle.The contents of water,crude protein,crude fat and muscle glycogen all showed a decreasing trend,and the consumption of glycogen was the largest.Less loss of nutrients before live transport was observed in the gradient cooling groups compared with the other groups.The microstructure also shows that the closed shell muscles in the gradient cooling group were closely arranged without an obvious fracture.This study indicates that inducing P.yessoensis to enter dormancy or semidormancy state by gradient cooling and then keeping them alive without water,is beneficial to improving the survival rate of living P.yessoensis,reducing the loss of nutrients during the live transport,and maintaining the vitality of living P.yessoensis,so it is more conducive to its anhydrous living-preservation.