Periodontitis is an infectious polymicrobial, immuno-inflammatory disease of multifactorial aetiology that has an impact on the health, production and welfare of ruminants. The objective of the present study was to determine the microbial profiles present in the gingival sulcus of cattle considered periodontally healthy and in the periodontal pocket of animals with periodontitis lesions using high-throughput bacterial 16S rRNA gene sequencing. Subgingival biofilm samples were collected from 40 cattle with periodontitis and 38 periodontally healthy animals. In total, 1923 OTUs were identified and classified into 395 genera or higher taxa. Microbial profiles in health differed significantly from periodontitis in their composition (p < 0.0001, F = 5.30; PERMANOVA) but no statistically significant differences were observed in the diversity of healthy and periodontitis microbiomes. The most prevalent taxa in health were Pseudomonas, Burkholderia and Actinobacteria, whereas in disease these were Prevotella, Fusobacterium and Porphyromonas. The most discriminative taxa in health were Gastranaerophilales, Planifilum and Burkholderia, and in disease these were Elusimicrobia, Synergistes and Propionivibrio. In conclusion, statistically significant difference exists between the microbiome in bovine oral health and periodontitis, with populations showing 72.6% dissimilarity. The diversity of the bacteria found in health and periodontitis were similar and bacteria recognised as periodontal pathogens showed increased abundance in disease. In this context, the main components of bacterial homeostasis in the biofilm of healthy sites and of dysbiosis in periodontal lesions provide unprecedented indicators for the evolution of knowledge about bovine periodontitis.

Periodontitis is a polymicrobial infectious disease that causes occlusion change, tooth loss, difficulty in rumination, and premature culling of animals. This study aimed to detect species of the genera Porphyromonas and Prevotella present in the periodontal pocket of sheep with lesions deeper than 5mm (n=14) and in the gingival sulcus of animals considered periodontally healthy (n=20). The presence of microorganisms was evaluated by polymerase chain reaction (PCR) using specific primers for Porphyromonas asaccharolytica, Porphyromonas endodontalis, Porphyromonas gingivalis, Porphyromonas gulae, Prevotella buccae, Prevotella intermedia, Prevotella loescheii, Prevotella melaninogenica, Prevotella nigrescens, Prevotella oralis, and Prevotella tannerae. Prevalence and risk analysis were performed using Student's t-test and Spearman's correlation. Among the Prevotella and Porphyromonas species detected in the periodontal lesions of sheep, P. melaninogenica (85.7%), P. buccae (64.3%), P. gingivalis (50%), and P. endodontalis (50%) were most prevalent. P. gingivalis (15%) and P. oralis (10%) prevailed in the gingival sulcus. P. gulae and P. tannerae were not detected in the 34 samples studied. Data evaluation by t-test verified that occurrence of P. asaccharolytica, P. endodontalis, P. gingivalis, P. buccae, P. intermedia, P. melalinogenica, and P. nigrescens correlated with sheep periodontitis. The findings of this study will be an important contribution to research on pathogenesis of sheep periodontitis and development of its control measures.

The objective of this study was to describe the epidemiological, clinical and pathological aspects of an outbreak of periodontitis in sheep that occurred on a rural property in Benevides, in the state of Pará, Brazil. The first clinical signs of this disease in the herdvisible nodular swollen mandible -were observed about one month after the sheep began grazing on a recently renovated Panicum maximum cv. Massai pasture; the animals were also supplemented with elephant grass (Pennisetum purpureum). From the 545 adult Santa Ines, Dorper, Texel and crossbred sheep, 20 (3.7%) showed facial bulging, particularly of the mandible. These 20 sheep, which were generally over 36 months of age, had low body condition scores as well as dull and ruffled coats; many of them had loose or missing pre, upper or lower molars, showed the formation of abscesses and fistulas, exhibited pain upon palpation and had difficulty chewing. In the same herd, the prevalence of periodontal lesions at the premolars and molar teeth was evaluated via post-mortem examination of 39 young and 17 adult sheep. In 51.3% (20/39) of adolescents and in 100% of adults, periodontal lesions were found at least at one tooth of the dental arch, with unilateral or bilateral periodontal lesions at the maxillary and mandibular teeth. Histopathological analysis of 13 sheep revealed pyogranulomatous inflammation. The second and third maxillary premolars were the teeth that were most affected in young animals, whereas the third pre-molar and the molars, of the maxilla and mandible, were most often affected in adults. These lesions led to severe bone destruction, alterations in the dental arch, occlusion, tooth loss and periodontal abscesses. The epidemiological and clinic-pathological characteristics of this periodontitis outbreak, described here for the first time in sheep in Brazil, were similar to those for bovine periodontitis ("cara inchada"). No mesmo rebanho, a prevalência de lesões periodontais nos dentes pré-molares e molares foi avaliada por meio do exame post-mortem em 39 ovinos jovens e 17 adultos. Assim, 51,3% (20/39) dos jovens e todos os adultos apresentavam lesões periodontais em pelo menos um dos dentes da arcada, com ocorrência uni ou bilateral nos maxilares e mandibulares. A análise histopatológica de 13 animais revelou processo inflamatório piogranulomatoso. Os dentes mais afetados nas arcadas dos animais jovens foram os segundo e terceiro pré-molares maxilares. Já nos adultos foram o terceiro pré-molar e os molares, tanto maxilares quanto mandibulares. As lesões causaram severa destruição óssea, alteração na arcada dentária, na oclusão, perda dental e ocorrência de abscessos periodontais. As características epidemiológicas e clínico-patológicas do surto de periodontite em ovinos, aqui descritos originalmente nesta espécie animal no País, assemelham-se às da periodontite bovina ("cara inchada").TERMOS DE INDEXAÇÃO: Doença periodontal, periodontite, epidemiologia, ovinos.

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Introduction. Periodontitis, one of the most common oral disorders in sheep, is caused by a mixed and opportunistic microbiota that severely affects the health and welfare of animals. However, little is known about the ecological processes involved and the composition of the microbiota associated with the development of the disease. Hypothesis/Gap Statement. Using high-throughput sequencing of the 16S ribosomal RNA gene and network analysis it would be possible to discriminate the microbiomes of clinically healthy sheep and those with periodontitis and possibly identify the key microorganisms associated with the disease. Aim. The present study aimed to characterise the composition of dental microbiomes and bacterial co-occurrence networks in clinically healthy sheep and animals with periodontitis. Methodology. Dental biofilm samples were collected from ten sheep with periodontitis and ten clinically healthy animals. Bacteria were identified using high-throughput sequencing of the 16S ribosomal RNA gene. Results. The most prevalent genera in the dental microbiota of sheep with periodontitis were Petrimonas , Acinetobacter , Porphyromonas and Aerococcus . In clinically healthy animals, the most significant genera were unclassified Pasteurellaceae, Pseudomonas, and Neisseria. Fusobacterium was found at high prevalence in the microbiomes of both groups. The dental microbiota of sheep in the two clinical conditions presented different profiles and the diversity and richness of bacteria was greater in the diseased animals. Network analyses showed the presence of a large number of antagonistic interactions between bacteria in the dental microbiota of animals with periodontitis, indicating the occurrence of a dysbiotic community. Through the interrelationships, members of the Prevotella genus are likely to be key pathogens, both in the dental microbiota of healthy animals and those with periodontitis. Porphyromonas stood out among the top three nodes with more centrality and the largest number of hubs in the networks of animals with periodontitis. Conclusion. The dental biofilm microbiota associated with ovine periodontitis is dysbiotic and with significant antagonistic interactions, which discriminates healthy animals from diseased animals and highlights the importance of key bacteria, such as Petrimonas , Porphyromonas , Prevotella and Fusobacterium species.