采用Illumina MiSeq测序技术比较日本鲭和大黄鱼冷藏期间的腐败特性

为比较日本鲭和大黄鱼肌肉中微生物和代谢功能的变化及其与鱼肉腐败特性之间的关系，本研究检测了2种鱼在冷藏过程中的理化指标和菌落总数的变化，利用Illumina Miseq测序技术分析细菌群落变化，并利用皮尔森相关性分析检验微生物与鱼肉腐败及组胺产生相关性，结合功能预测分析细菌群落组成与代谢功能之间的关系。结果显示，冷藏期间日本鲭和大黄鱼的pH、挥发性盐基氮、组胺、菌落总数等均呈上升趋势，且日本鲭上升较快；冷藏末期2种鱼TVB-N值和组胺含量分别达到76.34、59.98和59.92、3.11 mg/100 g；日本鲭肌肉中细菌丰富度和多样性先增加后减少，大黄鱼则整体呈下降趋势；2种鱼肌肉中的优势腐败菌均为希瓦氏菌属；日本鲭体内与TVB-N产生相关的菌共12种，其中10种与组胺产生具有显著相关性；大黄鱼体内与TVB-N产生相关的菌共7种，但未检测出与组胺产生具有相关性的细菌；冷藏过程中氨基酸代谢和碳水化合物代谢为最主要的代谢通路，日本鲭样品组氨酸、精氨酸、脯氨酸等氨基酸代谢相关基因和丁酸丁酯代谢、丙酸酯代谢及丙酮酸代谢丰度均显著高于同一时期的大黄鱼，本实验从微生物代谢水平解释了日本鲭比大黄鱼更易腐败的原因，为不同水产品腐败特性的研究提供新思路。

Comparative analysis of the spoilage characteristics of Scomber japonicus and Larimichthys crocea during refrigerated storage byIllumina Miseq sequencing technology

To compare microbial community structure, diversity and metabolic potential, and analyze their relationships with the spoilage characteristic between Scomber japonicus and Larimichthys crocea, Illumina MiSeq sequencing technology was used to sequence the 16S rRNA V3-V4 hypervariable region of bacteria, and the physicochemical and microbiological indices including pH, total volatile basic nitrogen (TVB-N), histamine and aerobic plate count (APC) were detected. The correlation between microbes and fish spoilage and histamine producing was investigated by Pearson analysis, and the relationship between bacterial community composition and metabolic function was also predicted by phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt). The results showed that the pH, TVB-N, histamine content and APC in both fish fillets increased with the storage time extention, however their values in S. japonicus fillet increased faster and kept higher than those in L. crocea throughout storage. TVB-N and histamine content reached 76.34 mg/100 g, 59.92 mg/100 g in S. japonicus, while 59.98 mg/100 g, 3.11 mg/100 g in L. crocea at the end of storage, respectively. An increase tendency was observed in richness and diversity of bacteria in S. japonicus muscle and then followed by a decrease during the storage, while a sustained increase tendency was observed in that of L. crocea. Shewanella was the dominant bacteria in fillets of both S. japonicus and L. crocea. Twelve types of bacteria in S. japonicus were screened as TVB-N correlation bacteria, ten of which also showed significant correlation with the histamine producing, meanwhile seven types of bacteria in L. crocea were screened as TVB-N correlation bacteria, however, no bacterium showed correlation with histamine producing. Amino acid metabolism and carbohydrate metabolism were higher than other metabolism during the storage. The abundance of function genes related to amino acids metabolism and carbohydrate metabolism in S. japonicus was enormously higher than that in L. crocea throughout the storage period such as histidine, arginine and proline metabolism and butanoate metabolism, propanoate metabolism and pyruvate metabolism, respectively. This may partially explain why S. japonicus was more perishable than L. crocea from the level of metabolism of the bacterial community. Our study provided a new method to understand the spoilage characteristics of different aquatic products from the perspective of bacterial community and their metabolism related function genes.