基于高通量测序的大黄鱼表面微生物群落组成及变化分析

为了探究茶黄素对低温贮藏大黄鱼表面附着的微生物组成的影响情况，本实验以空白处理和0.3 mol/L Vc溶液浸泡处理为对照，采用0.3 mol/L茶黄素对冷藏和冻藏大黄鱼分别进行浸泡处理，通过对大黄鱼表面附着微生物提取及高通量测序分析，获得不同处理样品中微生物组成及变化情况。结果表明，大黄鱼样本中有效序列范围为22879~55910条，Operational taxonomic unit（OTU）范围为28~49，其中以采用Vc浸泡处理后冻藏大黄鱼OTU数最低。实验组的Chao1值、Shannon指数和Simpson指数与空白处理组相比均有明显变化，其中Shannon指数分别下降17.80%和13.79%，Simpson指数分别上升50.80%和71.72%，表明茶黄素对大黄鱼表面菌落多样性和丰富度具有显著影响。经过茶黄素处理后，大黄鱼表面菌落分布发生了变化，冷藏条件下的大黄鱼表面的类香味菌属、嗜冷杆菌属、黄杆菌属的相对丰度占比从20.55%、11.02%、7.38%均下降到1%以下，冻藏条件下的不动杆菌属等菌属生长受到抑制。以上结果说明，茶黄素具有较好的抗氧化性，对脂肪含量较高的大黄鱼表面微生物菌落组成有一定的影响，可以抑制部分菌属生长，延长大黄鱼贮藏时间。研究结果可为大黄鱼品质保障、复合生物保鲜剂的开发等提供基础参考。

Analysis Microbial Community on the Surface of Large Yellow Croaker (Larimichthys crocea) Based on High-throughput Sequencing

To investigate the effect of theaflavin on the microbial composition on the surface of large yellow croaker (Larimichthys crocea) in low-temperature storage, microbial composition and changes in different samples were obtained by microbial extraction and high-throughput sequencing analysis after soaking the refrigerated and frozen yellow croaker with 0.3 mol/L theaflavin and 0.3 mol/L Vc solution. The results showed that the effective sequence range was 22879~55910, and the operational taxonomic unit (OTU) range was 28~49 in large yellow croaker. The number of OTUs in the frozen large yellow croaker after Vc soaking was the lowest. The Chao1 value, Shannon index, and Simpson index of refrigerated and frozen large yellow croaker treated with theaflavin were significantly changed compared with the blank group, among that Shannon index decreased by 17.80% and 13.79%, Simpson index increased by 50.80% and 71.72% respectively, indicating that theaflavin had a significant effect on the colony diversity and richness of bacteria on the surface of large yellow croaker. The surface colony distribution of the large yellow croaker was changed, the relative abundance of Myroides, Psychrobacter and Flavobacterium on the surface of refrigerated large yellow croaker treated with theaflavin decreased from 20.55%, 11.02% and 7.38% to less than 1%, and the growth of Acinetobacter was inhibited by theaflavin treatment. Taken together, theaflavin had a good antioxidative effect on the microbial composition on the surface of large yellow croaker with high-fat content, which could inhibit bacteria growth and prolong the storage time of large yellow croaker. The research provides a basic reference for the quality assurance of large yellow croaker and the development of compound biological preservative.