Assessment of the lung microbiota in dogs: influence of the type of breed, living conditions and canine idiopathic pulmonary fibrosis

BACKGROUND: Literature about the lung microbiota (LM) in dogs is sparse. Influence of breed and living conditions on the LM in healthy dogs is currently unknown, as well as the influence of chronic respiratory diseases such as canine idiopathic pulmonary fibrosis (CIPF) in West highland white terriers (WHWTs). Aims of this study were (1) to assess the characteristics of the healthy LM according to breed and living conditions, and (2) to study LM changes associated with CIPF in WHWTs. Forty-five healthy dogs divided into 5 groups: domestic terriers (n = 10), domestic shepherds (n = 11), domestic brachycephalic dogs (n = 9), domestic WHWTs (n = 6) (H-WHWTs) and experimental beagles (n = 9) and 11 diseased WHWTs affected with CIPF (D-WHWTs) were included in the study to achieve those objectives. RESULTS: In healthy domestic dogs, except in H-WHWTs, the presence of few discriminant genera in each type of breed was the only LM modification. LM of experimental dogs displayed a change in b-diversity and an increased richness compared with domestic dogs. Moreover, Prevotella_7 and Dubosiella genera were more abundant and 19 genera were discriminant in experimental dogs. LM of both H-WHWTs and D-WHWTs revealed increased abundance of 6 genera (Brochothrix, Curvibacter, Pseudarcicella, Flavobacteriaceae genus, Rhodoluna and Limnohabitans) compared with other healthy domestic dogs. Brochothrix and Pseudarcicella were also discriminant in D-WHWTs compared with H-WHWTs and other healthy domestic dogs. CONCLUSIONS: In domestic conditions, except for H-WHWT, the breed appears to have minor influence on the LM. LM modifications were found in experimental compared with domestic living conditions. LM modifications in H-WHWTs and D-WHWTs compared with other healthy domestic dogs were similar and seemed to be linked to the breed. Whether this breed difference might be related with the high susceptibility of WHWTs for CIPF requires further studies.