Dental and Periodontal Health in Free-Ranging Swedish Brown Bears (Ursus arctos)

A retrospective study on the prevalence of main clinical findings in brown bears (Ursus arctos) rescued from substandard husbandry conditions

Brown bears (Ursus arctos) are kept under varied captive conditions, some of which may greatly compromise their welfare. FOUR PAWS is an NGO that rescues some of these bears kept in substandard conditions and houses them in species-appropriate sanctuaries, where preventive and reactive veterinary care is provided. This retrospective study aims to provide an overview of pathologies and clinical abnormalities reported in veterinary records and their prevalence according to body system affected and pre-rescue bear origin. Origin was categorised as subzoo (bears coming from substandard zoos), dancing (used to "dance" upon a music cue), restaurant (used to attract clients), private keeping (used for various purposes, such as photo props), circus (used for shows), and bear-baiting (exploited for hunting dog training in baiting stations). Clinical findings were extracted from reports of veterinary examinations done from 2006 to 2021, during rescue, routinely, in response to clinical signs, and/or post-mortem. Their prevalence was calculated according to the body system affected and neoplasia (specific group independent from the organ) over the findings' total number. Prevalence was also calculated according to pre-rescue origin (general and relative values in proportion to the number of reports per origin). Results refer to 302 veterinary reports of 114 bears examined, rescued from 1998 to 2021, with the age at rescue varying from a few months to 30 years (median 13 years). The total number of clinical findings was 1,003, and the systems with more findings were oral cavity (56.0%), abdominal cavity and digestive system (7.9%), integumentary (7.9%), ocular systems (7.7%), and musculoskeletal (7.6%). Findings involving other body systems and neoplasia were less prevalent (≤2.8%). Results showed a higher prevalence of some clinical findings for bears rescued from certain origins compared to others. Straightforward associations between pre-rescue origin and clinical findings were not feasible due to unknown anamnesis and details on pre-rescue conditions, and because some housing and management characteristics might be transversal to origins. Results suggest that bears rescued from certain origins were prone to specific clinical findings, supporting the need for the creation of ad hoc preventive veterinary and husbandry management plans after rescue, thus contributing to the improvement of captive bear welfare.

The Plaque Microbiota Community of Giant Panda (Ailuropoda melanoleuca) Cubs With Dental Caries

Dental caries severely hinders efficient access to adequate energy in wildlife. Different food supplies will develop characteristic plaque, and the microorganisms of these plaque are closely related to dental health. Here, plaque samples from panda cubs with caries and caries-free were collected for 16S rRNA high-throughput sequencing. All sequences clustered into 337 operational taxonomic units (OTUs; 97% identity), representing 268 independent species belonging to 189 genera, 98 families, 51 orders, 24 classes, and 13 phyla. Two groups shared 218 OTUs, indicating the presence of a core plaque microbiome. α diversity analysis showed that the microbial diversity in plaques with caries exceeded that of caries-free. The dominant phyla of plaque microbiota included Proteobacteria, Bacteroidetes, Firmicutes, Fusobacteria, and Actinobacteria. The dominant genera included unclassified Neisseriaceae, Actinobacillus, Lautropia, Neisseria, Porhyromonas, unclassified Pasteurellaceae, Moraxella, Streptococcus, Bergeywlla and Capnocytophaga. β diversity analysis showed that the plaque microbial community structure was different between two groups. Using LEfSe analysis, 19 differentially abundant taxa were identified as potential biomarkers. Finally, function predictions analysis showed All the energy related metabolic pathways on KEGG level 2 were enriched in caries-active group. Consistent with the mainstream caries-causing narrative, our results illuminate the lack of information regarding the oral microflora composition and function within giant panda cubs.

Dental and Temporomandibular Joint Pathology of the North American Brown Bear (Ursus arctos horribilis, Ursus arctos middendorffi and Ursus arctos sitkensis)

Museum specimens (maxillae and mandibles) from 393 North American brown bears (Ursus arctos) from Alaska were examined macroscopically according to predefined criteria and 204 specimens were included in this study. The specimens were acquired between 1905 and 2012. There were 99 specimens (48.5%) from male animals, 87 (42.7%) from female animals and 18 (8.8%) from animals of unknown sex. The ages of the animals ranged from neonate to adult, with 92 adults (45.1%) and 112 young adults (54.9%) included and neonates/juveniles excluded from the study. The number of teeth available for examination was 6,525 (76.2%); 8.6% of teeth were absent artefactually, 0.8% were deemed absent due to acquired tooth loss and 14.5% were absent congenitally. None of the brown bears had supernumerary teeth, persistent deciduous teeth or abnormally formed crowns. Only four of the specimens in the present population were affected by enamel hypoplasia and one specimen contained two mandibular fourth premolar teeth with one root instead of two. All 204 specimens displayed at least some degree of attrition/abrasion, affecting 63% of all teeth, ranging from mild wear of the enamel to deep abrasion associated with pulp exposure. Ten-times more adult than young adult specimens had abrasion causing pulp exposure, while more young adults showed mild attrition/abrasion. Dental fractures were noted in one-third of brown bears and in 3.0% of the total number of present teeth. More adult brown bears had dental fractures than young adults. There were 11 specimens (5.4%) that displayed overt periapical disease, affecting a total of 20 dental alveoli (0.22%), with adults significantly more affected than young adults. Some degree of periodontitis was seen in 145 specimens (71.1%), affecting 13.6% of all dental alveoli. Nearly one-third (29.9%) of skulls displayed skeletal and/or dental malocclusion, most commonly a level bite. Lesions consistent with temporomandibular joint (TMJ) osteoarthritis were found in 27 specimens (13.2%). Caries lesions were discovered in four specimens (2.0%), affecting eight teeth in total. Although the clinical significance of dental and TMJ pathology in the brown bear remains elusive, the occurrence and severity of some of these lesions may play an important role in the morbidity of this species.

Dental and Temporomandibular Joint Pathology of the American Black Bear (Ursus americanus)

Museum specimens (maxillae and/or mandibles) from 371 American black bears (Ursus americanus) acquired between 1889 and 2006 were examined macroscopically according to predefined criteria, and 348 were included in this study. Of the 348 specimens, 126 (36.2%) were from male animals, 106 (30.5%) were from female animals and 116 (33.3%) were from animals of unknown sex. Specimen ages ranged from young adult (n = 63, 18.1%) to adult (n = 285, 81.9%), with juveniles excluded from the study. The number of teeth available for examination was 12,019 (82.2%); 7.0% of teeth were absent artefactually, 0.4% were deemed absent due to acquired tooth loss and 9.7% were absent congenitally. In 43 specimens (12.3%), 82 teeth (0.68%) were small vestigial structures with crowns that were flush with the level of surrounding alveolar bone. The remaining teeth (99.3%) were of normal morphology. Only three supernumerary teeth and three instances of enamel hypoplasia were encountered. Persistent deciduous teeth or teeth with an aberrant number of roots were not encountered in any of the specimens. Approximately one-third of the teeth examined (4,543, 37.8%) displayed attrition/abrasion, affecting nearly all of the specimens (n = 338, 97.1%). Incisor and molar teeth accounted for 52.5% and 34.3% of the affected teeth, respectively, with significantly more adults affected than young adults. Dental fractures were noted in 63 bears, affecting 18.1% of specimens and 1.0% of the total number of present teeth. The canine teeth were most often fractured, with adults having significantly more complicated crown fractures of these teeth than young adults. There were 11 specimens (3.2%) that displayed periapical lesions, affecting 12 (0.1%) dental alveoli. There were 179 specimens (51.4%) displaying bony changes indicative of periodontitis, affecting 816 (6.8%) dental alveoli. The proportion of adult bears affected by periodontitis (57.9%) was significantly greater than that of young adults (22.2%). Exactly half of the specimens (n = 174) possessed lesions consistent with mild temporomandibular joint osteoarthritis. The occurrence and severity of the dental pathology encountered in this study may play an important role in the morbidity and mortality of the American black bear.

Gastric Dilatation and Volvulus in Brown Bear (Ursus arctos)

Gastric dilatation and volvulus is a life-threatening condition characterized by rapid accumulation of food and gases that cause displacement and distension of the stomach. The large and giant, deep-chested breeds of dogs are at higher risk for developing the gastric dilatation and volvulus. Uncommonly, it can also develop in cats, but it is also described in free-range polar bears.

A case of gastric dilatation and volvulus in a brown bear (Ursus arctos) is described in this paper. This case was characterized by lack of any previous symptoms, sudden death, as well as macroscopic findings during necropsy - twisted distended stomach, congested displaced spleen and necrotic gastric wall. According to the available data this is the first described case report of the gastric dilatation and volvulus in brown bear (Ursus arctos).

Dental and Temporomandibular Joint Pathology of the Polar Bear (Ursus maritimus)

Museum specimens (maxillae and/or mandibles) from 317 polar bears (Ursus maritimus) were examined macroscopically according to predefined criteria and 249 specimens were included in this study. The specimens were acquired between 1906 and 2011. There were 126 specimens (50.6%) from male animals, 93 (37.3%) from female animals and 30 (12.1%) from animals of unknown sex. The ages of the animals ranged from neonate to adult, with 125 adults (50.2%) and 124 young adults (49.8%) included and neonates/juveniles excluded from the study. The number of teeth available for examination was 7,638 (73.5%); 12.3% of teeth were absent artefactually, 0.8% were deemed absent due to acquired tooth loss and 13.4% were absent congenitally. With respect to tooth morphology, 20 teeth (0.26% of available teeth) in 18 specimens (7.2% of available specimens) were small vestigial structures with crowns that were flush with the level of surrounding alveolar bone. One supernumerary tooth and one tooth with enamel hypoplasia were encountered. Persistent deciduous teeth and teeth with an aberrant number of roots were not found. Relatively few teeth (3.7%) displayed attrition/abrasion, 90% of which were the maxillary and mandibular incisor teeth, in 41 polar bears (16.5%). Nearly twice as many adult specimens exhibited attrition/abrasion as those from young adults; significantly more males were affected than females. Dental fractures were noted in 52 polar bears, affecting 20.9% of specimens and 1.3% of the total number of teeth present. More adult polar bears had dental fractures than young adults. There were 21 specimens (8.4%) that displayed overt periapical disease, affecting a total of 24 dental alveoli (0.23%). Some degree of periodontitis was seen in 199 specimens (79.9%); however, only 12.6% of dental alveoli had bony changes indicative of periodontitis. Lesions consistent with temporomandibular joint osteoarthritis (TMJ-OA) were found in 23 specimens (9.2%). TMJ-OA was significantly more common in adults than in young adults and in males than in females. Although the clinical significance of dental and TMJ pathology in the polar bear remains elusive, the occurrence and severity of these lesions may play an important role in the morbidity and mortality of this species.

DENTAL ABNORMALITIES OF EIGHT WILD QINLING GIANT PANDAS (AILUROPODA MELANOLEUCA QINLINGENSIS), SHAANXI PROVINCE, CHINA

Eight adult (six male and two female) wild Qinling giant pandas (Ailuropoda melanoleuca qinlingensis) from China National Foping Nature Reserve were tracked, and their dental data collected and recorded from October 2010 to April 2014. Each panda had dental abnormalities of varying severity. Dental wear and fracture were the most common conditions. Absent teeth were common, with premolars missing most often. Mild caries were present in five molar teeth between two animals. Different degrees of dental plaque and calculus occurred in all animals but without severe periodontal disease. Two animals with severe dental abnormalities died due to intestinal problems. Large segments of bamboo were found in their intestinal tracts, and intestinal perforation and ulcers were evident, indicating dental abnormalities can be an important factor in the health of wild giant pandas and may lead to death. Further research with larger sample sizes of wild and captive giant pandas will be required to substantiate the relationship between dental abnormalities and mortality in giant pandas.

Salivary amylase - The enzyme of unspecialized euryphagous animals

INTRODUCTION

Alpha-amylase (EC 3.2.1.1) is the most abundant enzyme in the saliva of man and of several vertebrates. In humans, salivary amylase is mainly formed in the parotid gland; its activity is of high inter-individual and intra-individual variability. The physiological functions of α-amylase have not yet been explored completely. It is well known that the enzyme cleaves the α-(1,4)-glycosidic bonds of polysaccharides. Furthermore it plays an important role in initial bioadhesion in man, facilitating carbohydrate metabolism and bacterial adherence at the tooth surface and therewith caries initiation. Nevertheless, it is still a matter of interest why humans have such high amounts of salivary amylase.

OBJECTIVE

The review presents an evolutionary approach by considering salivary amylase in the animal kingdom with special focus on mammalians divided into the three main nutritional types carnivores, herbivores, and omnivores; it was postulated that for most mammalian animals salivary α-amylase is essential.

RESULTS

The enzyme has been detected in saliva of some herbivores and many omnivorous animals, but not in pure carnivores. Focusing on ruminants, negligible levels or an absence of α-amylase was determined. Presence and activity probably differ depending on the species-specific diet. Animals feeding on unripe fruits, seeds, roots and bulbs exhibit higher activity of salivary α-amylase than species consuming ripe fruits, insects, and vertebrates.

CONCLUSION

In contrast to carnivores and most herbivores, omnivores have considerable amounts of amylase in their saliva. Though, the starch-digesting enzyme has been investigated well, the physiological function of amylase in saliva has not yet been explored completely. It can be hypothesized that nutritional habits affect expression of enzymes in the saliva of animals. It has to be verified, whether α-amylase is genetically or epigenetically determined. As a consequence of the development of agriculture, and following dietary changes, amylase can be recognized as a nutritional and evolutionary marker. Interdisciplinary evolutionary research might offer new perspectives for preventive dentistry.

Dental abnormalities in eight captive giant pandas (Ailuropoda melanoleuca) in China

Dental data from eight adult giant pandas (Ailuropoda melanoleuca) (four females and four males) were collected at the Beijing Zoo from February 2009 to July 2010. Examination findings were recorded in dental charts. All the pandas had different degrees of tooth wear. Incisors, canines and second premolars had the most abnormalities. Five animals had caries; molars were the most affected. Chip fractures were found in seven teeth (incisor, canine and premolar) of five pandas; two had complicated fractures of their canines. Premolars and other teeth were missing in three pandas. Different degrees of dental plaque and calculus were found in all animals. Two pandas had mild gingivitis; the depth of periodontal pockets in all pandas was normal (0-2 mm). Five pandas had abnormal tooth mobility. Samples of dental plaque were collected for microbial culture. Two hundred and fifty-three bacterial strains belonging to 48 species of 23 genera were isolated. Streptococcus, Moraxella, Peptostreptococcus and Porphyromonas were the dominant genera. Further research with larger sample sizes of free-ranging and captive giant pandas will be required in order to demonstrate the absence of the premolar tooth, tooth fractures and the relatively low prevalence of periodontal disease in captive giant pandas.