Table_2_Comparison of Oropharyngeal Microbiota in Healthy Piglets and Piglets With Respiratory Disease.docx

Porcine respiratory disease (PRD) is responsible for severe economic losses in the swine industry worldwide. Our objective was to characterize the oropharyngeal microbiota of suckling piglets and compare the microbiota of healthy piglets and piglets with PRD. Oropharyngeal swabs were collected from healthy (Healthy_A, n = 6; Healthy_B, n = 4) and diseased (PRD_A, n = 18; PRD_B, n = 5) piglets at 2–3 weeks of age from two swine farms in Guangdong province, China. Total DNA was extracted from each sample and the V3-V4 hypervariable region of the 16S rRNA gene was amplified and sequenced using the Illumina MiSeq platform. No statistically significant differences were observed in bacterial diversity and richness between the healthy and PRD groups in the two farms except for Shannon index in farm A. Principal coordinates analysis (PCoA) showed structural segregation between diseased and healthy groups and between groups of different farms. Among all samples, the phyla Firmicutes, Proteobacteria, and Bacteroidetes were predominant. At the genus level, Streptococcus, Lactobacillus, and Actinobacillus were the core genera in the oropharynx of healthy piglets from the two farms. Significant differences in bacterial taxa were found when the microbiota was compared regarding the health status. In farm A, the percentages of Moraxella and Veillonella were higher in the PRD group, while only Porphyromonas was significantly increased in the PRD group in farm B (p < 0.05). Compared to PRD groups, statistically significant predominance of Lactobacillus was observed in the healthy groups from both farms (p < 0.05). Our findings revealed that Moraxella, Veillonella, and Porphyromonas may play a potential role in PRD and Lactobacillus may have a protective role against respiratory diseases.

猪呼吸道疾病（Porcine respiratory disease, PRD）给全球养猪业造成了严重的经济损失。本研究旨在解析哺乳仔猪的口咽微生物组（oropharyngeal microbiota）特征，并对比健康仔猪与感染PRD仔猪的微生物组差异。我们从中国广东省的两个养猪场采集了2~3周龄仔猪的口咽拭子样本，其中健康仔猪组分为Healthy_A（n=6）与Healthy_B（n=4），患病仔猪组分为PRD_A（n=18）与PRD_B（n=5）。对每份样本提取总DNA，采用Illumina MiSeq平台对16S rRNA基因的V3-V4高变区进行扩增与测序。在两个养猪场的健康组与PRD患病组间，除A场的香农指数（Shannon index）存在显著差异外，细菌多样性与丰富度均无统计学显著性差异。主坐标分析（Principal coordinates analysis, PCoA）结果显示，患病组与健康组间以及不同猪场的样本组间均存在群落结构分离。所有样本中的优势菌门为厚壁菌门（Firmicutes）、变形菌门（Proteobacteria）与拟杆菌门（Bacteroidetes）。在属水平上，两个猪场健康仔猪口咽部的核心菌属为链球菌属（Streptococcus）、乳杆菌属（Lactobacillus）与放线杆菌属（Actinobacillus）。基于健康状态对比微生物组时，各细菌分类单元存在显著差异：在A场，PRD患病组的莫拉氏菌属（Moraxella）与韦荣球菌属（Veillonella）占比更高；而在B场，仅卟啉单胞菌属（Porphyromonas）在PRD患病组中显著升高（p < 0.05）。与PRD患病组相比，两个猪场的健康组均表现出乳杆菌属的显著富集（p < 0.05）。本研究结果表明，莫拉氏菌属、韦荣球菌属与卟啉单胞菌属可能在PRD的发生中发挥潜在致病作用，而乳杆菌属则可能对呼吸道疾病具有保护作用。