Oral microbiota play a prominent role in canine periodontal disease and wet foods are often blamed for poor oral health, but canine oral microbial communities have been poorly studied. We aimed to determine differences in oral health measures, breath odor, and oral microbiota populations of dogs fed wet or dry food. Twelve adult dogs fed either a commercial dry (extruded) or commercial wet (canned) food for 6 wk were studied. Breath samples were measured for sulfur compounds, teeth were scored for plaque, calculus, and gingivitis by a blinded veterinary dentist, salivary pH was measured, and supragingival (SUP) and subgingival (SUB) plaque samples were collected for microbiota analysis. Plaque DNA was extracted and Illumina sequencing conducted. Phylogenetic data were analyzed using the CosmosID bioinformatics platform and SAS 9.4, with P<0.05 being significant and P<0.10 being trends. Plaque coverage tended to be higher (P<0.10) in dogs fed wet vs. dry food, but other oral health scores were not different. Dogs fed dry food had higher (P<0.05) salivary pH and lower (P<0.05) breath sulfur concentrations than those consuming wet food. Bacterial alpha diversity was higher in SUP than SUB samples, and a clear separation in beta diversity was observed between sample sites on principal coordinates analysis (PCoA) plots. In SUP samples, dogs fed wet food had a higher alpha diversity than dogs fed dry food, with PCoA plots showing a separation between wet and dry food. Relative abundances of Firmicutes, Synergistetes, and 10 bacterial genera were different (P<0.05) in SUB samples of dogs fed wet vs. dry food. Relative abundances of Fusobacteria and over 20 bacterial genera were different (P<0.05) in SUP samples of dogs fed wet vs. dry food. In general, oral health-associated bacterial taxa (Pasteurella, Capnocytophaga, Corynebacterium) were higher, while bacteria associated with poor oral health (Fretibacterium fastidiosum, Filifactor alocis, Treponema medium, Tannerella forsythia, Porphyromonas canoris, Porphyromonas gingivalis) were lower in dogs fed dry food. Such shifts in the oral microbiota may impact periodontal disease risk, but longer dietary intervention studies are required to confirm their role in the disease process. Our results suggest that dogs fed dry extruded foods have lower breath odor and tooth plaque buildup and an oral microbiota population more closely associated with oral health than dogs fed wet canned foods.

中文翻译：

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食用湿粮或干粮的成年犬的口腔微生物群

口腔微生物群在犬牙周病中发挥着重要作用，湿食经常被归咎于口腔健康不佳，但对犬口腔微生物群落的研究很少。我们旨在确定喂食湿粮或干粮的狗的口腔健康指标、呼吸气味和口腔微生物群的差异。研究了 12 只成年狗喂食商业干（挤压）或商业湿（罐头）食物 6 周。测量呼吸样本中的硫化合物，由不知情的兽医对牙齿的菌斑、牙结石和牙龈炎进行评分，测量唾液 pH 值，并收集龈上 (SUP) 和龈下 (SUB) 菌斑样本进行微生物群分析。提取斑块 DNA 并进行 Illumina 测序。使用 CosmosID 生物信息学平台和 SAS 9.4 分析系统发育数据，P＜0。05 是显着的，P<0.10 是趋势。喂食湿粮与干粮的狗的牙菌斑覆盖率往往更高（P<0.10），但其他口腔健康评分没有差异。与食用湿粮的狗相比，喂食干粮的狗的唾液 pH 值更高（P<0.05），而呼吸硫浓度更低（P<0.05）。SUP 中的细菌 α 多样性高于 SUB 样本，并且在主坐标分析 (PCoA) 图上的样本位点之间观察到β多样性的明显分离。在 SUP 样本中，喂食湿粮的狗比喂食干粮的狗具有更高的 alpha 多样性，PCoA 图显示湿粮和干粮之间的分离。在喂食湿粮和干粮的狗的 SUB 样本中，厚壁菌门、协同菌门和 10 种细菌属的相对丰度不同 (P<0.05)。在喂食湿粮和干粮的狗的 SUP 样本中，梭杆菌和 20 多种细菌属的相对丰度不同 (P<0.05)。一般来说，与口腔健康相关的细菌类群（巴斯德氏菌、Capnocytophaga、棒状杆菌）较高，而与口腔健康不良相关的细菌（Fretibacterium fastidiosum、Filifactor alocis、Treponema medium、Tannerella forsythia、Porphyromonas canoris、Porphyromonas gingivalis）在喂食的狗中较低干粮。口腔微生物群的这种变化可能会影响牙周病的风险，但需要更长时间的饮食干预研究来证实它们在疾病过程中的作用。我们的研究结果表明，与喂食湿罐头食品的狗相比，喂食干燥挤压食品的狗的口气气味和牙菌斑积聚较少，并且口腔微生物群与口腔健康的关系更密切。