State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Provincial Key Laboratory of Microbial Molecular Biology, College of Life Science, Hunan Normal University, Changsha, China.
Microbiologyopen. 2020 May;9(5):e996. doi: 10.1002/mbo3.996. Epub 2020 Mar 16.
Gut microbiota are known to play an important role in health and nutrition of the host and have been attracting an increasing attention. Farming of new lineages of grass carp and crucian carp has been developed rapidly as these species were found to outperform indigenous ones in terms of growth rate and susceptibility to diseases. Despite this rapid development, no studies have addressed the characteristics of their gut microbiota as a potential factor responsible for the improved characteristics. To reveal whether microbiomes of the new lineages are different from indigenous ones, and therefore could be responsible for improved growth features, intestinal microbiota from the new lineages were subjected to high-throughput sequencing. While the phyla Firmicutes, Fusobacteria and Proteobacteria were representing the core bacterial communities that comprised more than 75% in all fish intestinal samples, significant differences were found in the microbial community composition of the new linages versus indigenous fish populations, suggesting the possibility that results in the advantages of enhanced disease resistance and rapid growth for the new fish lineages. Bacterial composition was similar between herbivorous and omnivorous fish. The relative abundance of Bacteroidetes and Actinobacteria was significantly higher in omnivores compared to that of herbivores, whereas Cetobacterium_sp. was abundant in herbivores. We also found that the gut microbiota of freshwater fish in the Dongting lake area was distinct from those of other areas. Network graphs showed the reduced overall connectivity of gut bacteria in indigenous fish, whereas the bacteria of the new fish lineage groups showed hubs with more node degree. A phylogenetic investigation of communities by reconstruction of unobserved states inferred function profile showed several metabolic processes were more active in the new lineages compared to indigenous fish. Our findings suggest that differences in gut bacterial community composition may be an important factor contributing to the rapid growth and high disease resistance of the new fish lineages.
肠道微生物群被认为在宿主的健康和营养中发挥着重要作用，越来越受到关注。由于发现草鱼和鲫鱼的新谱系在生长速度和对疾病的易感性方面优于本地种群，因此这些新谱系的养殖得到了迅速发展。尽管发展迅速，但没有研究涉及它们的肠道微生物群作为潜在因素的特征，这些因素可能导致其生长特征得到改善。为了揭示新谱系的微生物组是否与本地种群不同，因此可能是导致生长特征改善的原因，对新谱系的肠道微生物组进行了高通量测序。虽然厚壁菌门、梭杆菌门和变形菌门代表了核心细菌群落，在所有鱼类肠道样本中占比超过 75%，但在新谱系与本地鱼类种群的微生物群落组成方面发现了显著差异，这表明新鱼类谱系在增强疾病抵抗力和快速生长方面具有优势的可能性。草食性和杂食性鱼类的细菌组成相似。与草食性鱼类相比，杂食性鱼类的拟杆菌门和放线菌门的相对丰度显著更高，而梭菌属在草食性鱼类中丰富。我们还发现，洞庭湖地区淡水鱼的肠道微生物群与其他地区的不同。网络图显示，本地鱼类的肠道细菌整体连通性降低，而新鱼类谱系群体的细菌则具有更多节点度的枢纽。通过未观察状态的重建进行群落的系统发育分析推断功能谱表明，与本地鱼类相比，新鱼类谱系中的几种代谢过程更为活跃。我们的研究结果表明，肠道细菌群落组成的差异可能是新鱼类谱系快速生长和高抗病性的重要因素。
