Data_Sheet_1_Whole genome analysis of host-associated lactobacillus salivarius and the effects on hepatic antioxidant enzymes and gut microorganisms of Sinocyclocheilus grahami.PDF

As a fish unique to Yunnan Province in China, Sinocyclocheilus grahami hosts abundant potential probiotic resources in its intestinal tract. However, the genomic characteristics of the probiotic potential bacteria in its intestine and their effects on S. grahami have not yet been established. In this study, we investigated the functional genomics and host response of a strain, Lactobacillus salivarius S01, isolated from the intestine of S. grahami (bred in captivity). The results revealed that the total length of the genome was 1,737,623 bp (GC content, 33.09%), comprised of 1895 genes, including 22 rRNA operons and 78 transfer RNA genes. Three clusters of antibacterial substances related genes were identified using antiSMASH and BAGEL4 database predictions. In addition, manual examination confirmed the presence of functional genes related to stress resistance, adhesion, immunity, and other genes responsible for probiotic potential in the genome of L. salivarius S01. Subsequently, the probiotic effect of L. salivarius S01 was investigated in vivo by feeding S. grahami a diet with bacterial supplementation. The results showed that potential probiotic supplementation increased the activity of antioxidant enzymes (SOD, CAT, and POD) in the hepar and reduced oxidative damage (MDA). Furthermore, the gut microbial community and diversity of S. grahami from different treatment groups were compared using high-throughput sequencing. The diversity index of the gut microbial community in the group supplemented with potential probiotics was higher than that in the control group, indicating that supplementation with potential probiotics increased gut microbial diversity. At the phylum level, the abundance of Proteobacteria decreased with potential probiotic supplementation, while the abundance of Firmicutes, Actinobacteriota, and Bacteroidota increased. At the genus level, there was a decrease in the abundance of the pathogenic bacterium Aeromonas and an increase in the abundance of the potential probiotic bacterium Bifidobacterium. The results of this study suggest that L. salivarius S01 is a promising potential probiotic candidate that provides multiple benefits for the microbiome of S. grahami.

作为中国云南省特有鱼类，滇池金线鲃（Sinocyclocheilus grahami）的肠道中蕴藏着丰富的潜在益生资源。然而，其肠道内具有益生潜能的细菌的基因组特征，以及这些细菌对滇池金线鲃的影响，目前仍未明确。本研究针对从人工繁育的滇池金线鲃肠道中分离得到的唾液乳杆菌（Lactobacillus salivarius）S01，开展了功能基因组学与宿主响应相关研究。结果显示，该菌株的基因组总长度为1737623 bp，GC含量为33.09%，共包含1895个基因，其中包括22个核糖体RNA（rRNA）操纵子与78个转运RNA（tRNA）基因。通过antiSMASH与BAGEL4数据库预测，共鉴定出3个抗菌物质相关基因簇。此外，人工注释验证发现，唾液乳杆菌S01的基因组中携带有与抗逆性、黏附性、免疫调节及其他益生潜能相关的功能基因。随后，通过向滇池金线鲃饲喂添加该菌株的饲料，在活体水平探究了唾液乳杆菌S01的益生功效。结果表明，潜在益生质补充可提升宿主肝脏中的抗氧化酶（超氧化物歧化酶SOD、过氧化氢酶CAT与过氧化物酶POD）活性，并降低氧化损伤产物丙二醛（MDA）水平。此外，本研究通过高通量测序技术对比了不同处理组滇池金线鲃的肠道微生物群落组成与多样性。结果显示，添加潜在益生质的实验组肠道微生物群落多样性指数显著高于对照组，表明该益生菌株可提升宿主肠道微生物多样性。在门分类水平上，潜在益生质补充组的变形菌门（Proteobacteria）丰度显著降低，而厚壁菌门（Firmicutes）、放线菌门（Actinobacteriota）与拟杆菌门（Bacteroidota）的丰度均有所提升。在属分类水平上，条件致病菌气单胞菌属（Aeromonas）的丰度显著下降，而潜在益生菌双歧杆菌属（Bifidobacterium）的丰度则有所上升。本研究结果表明，唾液乳杆菌S01是一株极具应用前景的潜在益生候选菌株，可为滇池金线鲃的肠道微生物组提供多重有益功效。