鱼袋保活中团头鲂存活率和肌肉品质的变化

Changes in survival rate and muscle quality of Megalobrama amblycephala in fish bags during the process of keeping-alive

为促进活鱼电商物流的发展,本实验采用鱼袋保活运输团头鲂,研究了保活条件对存活率的影响,以及保活过程中血液应激指标、肌肉品质的变化。结果显示,当运输环境温度为10℃,鱼和水质量比为1∶3,运输中使用水为曝气自来水时,鱼体存活率最高。在保活过程中,团头鲂血液的应激指标均呈现波动性变化趋势。但是整体上,皮质醇、尿素和丙二醛含量先增加后降低;乳酸脱氢酶含量先降低后增加;超氧化物歧化酶含量逐渐降低;过氧化氢酶、天冬氨酸转移酶和肌酐含量逐渐增加。在肌肉品质方面,白度值、剪切力、滴水损失整体上呈现先增加后降低的趋势;与0 h相比,保活72 h后粗蛋白、乳酸和糖原含量分别下降了19.0%、27.2%和50.0%;鲜味和苦味核苷酸类物质以及鲜度值K整体上均呈现逐渐增加的趋势;肌纤维间隙随保活时间的延长而逐渐增大。研究表明,在保活过程中,鱼体受到持续的应激,肌肉品质劣变。本研究可为鱼类的电商活运提供理论依据。

With the development of aquatic logistics industry,China has now formed a live fish transportation system mainly based on high-density live transportation,supplemented by single fish transportation through plastic fish bag filled with oxygenated water.Although keeping-alive with fish bags has the advantages of shortening the transportation intermediate link,improving the survival rate of fish,and promoting the sales of local specialty fish,there is relatively little research on stress response and muscle quality changes in live fish transported with fish bags,which greatly limits the development of this transportation method.In order to promote the development of live fish transportation industry,this study adopts the fish bag to preserve the survival of the blunt snout bream(Megalobrama amblycephala).Firstly,the influence of survival conditions(temperature,fish-water ratio,and water source)on the survival rate was studied,and the optimal survival conditions were determined;then,the changes in blood stress indicators and muscle quality of fish during the keeping-alive process were studied under the optimal conditions.The results showed that when the transportation environment temperature was 10 oC,the fish to water mass ratio was 1:3,and the water source was aerated tap water,the fish survival rate was the highest.The survival rates were 90%and 70%at 36 and 48 hours of keeping-alive process,respectively.During the keeping-alive process,the stress indicators in the blood of the bream showed a fluctuating trend.However,overall,the content of cortisol(COR),urea(URA),and malondialdehyde(MDA)increased first and then decreased;the content of lactate dehydrogenase(LDH)first decreased and then increased;the content of superoxide dismutase(SOD)gradually decreased;the content of catalase(CAT),aspartate transferase(AST),and creatinine(CR)gradually increased.In terms of muscle quality,physical indicators such as whiteness value,shear force,and drip loss show an overall trend of first increasing and then decreasing,which was consistent with the formation of pale,soft and exudative(PSE)meat after stress.Compared with 0 hour,the crude protein,lactate,and glycogen content decreased by 19.0%,27.2%,and 50.0%respectively after 72 hours of keeping-alive process;The nucleotide compounds of freshness(ADP,AMP,IMP)and bitterness(HxR,Hx),as well as the freshness value K,showed an overall increasing trend;the gap between muscle fibers gradually increased with the prolongation of survival time.This study has shown that during the keeping-alive process,fish are subjected to sustained stress,and the intensity of single stress may gradually weaken.The main reason for the deterioration of fish muscle quality may be related to physiological processes such as energy metabolism disorders.This study can provide a theoretical basis for the ecommerce logistics of fish by fish bags.However,further research is needed on how to effectively alleviate the stress response of fish during the transportation,thereby improving survival rate and muscle quality.