The respiratory microbiota and its impact on health and disease in dogs and cats: A One Health perspective

The nasal microbiota of two marine fish species: diversity, community structure, variability, and first insights into the impacts of climate change-related stressors

Vertebrate nasal microbiota (NM) plays a key role regulating host olfaction, immunity, neuronal differentiation, and structuring the epithelium. However, little is known in fish. This study provides the first comprehensive analysis of the NM in two marine fish species, the European seabass and the Atlantic cod. Given its direct environmental exposure, fish NM is likely influenced by seawater fluctuations. We analysed the community structure, specificity regarding seawater, and interindividual variability of 32-38 fish reared under ambient conditions. Additionally, we conducted an experiment to investigate the influence of acidification and a simplified heatwave on cod NM (three fish per replicate). High-throughput 16S rRNA sequencing revealed species-specific NM communities at the genus-level with Stenotrophomonas and Ralstonia dominating seabass and cod NM, respectively. This suggests potential habitat- or physiology-related adaptations. The most abundant bacterial genera in seabass NM were also present in seawater, suggesting environmental acquisition. Alpha diversity was highest in Brest seabass NM and variability greatest in Tromsø cod NM. Simulated climate change-related scenarios did not significantly alter cod NM structure. We propose a minimum of 13 cod rosettes per replicate for future studies. This research establishes a foundation for understanding marine fish NM and its response to environmental changes.

Six-year duration of upper respiratory tract signs in a cat secondary to a draining tract from an incomplete enucleation in the left orbit

This case report describes a 10-year-old spayed female domestic medium-hair cat with chronic upper respiratory signs related to a remnant of the left globe in the orbit after incomplete enucleation, causing a draining tract. A CT scan, complete blood (cell) count, biochemical analysis, rhinoscopy, biopsy, culture, histopathologic analysis, and surgical revision of enucleation were done. Complete blood (cell) count was unremarkable. Biochemical analysis showed mild hyperglycemia at 9.38 mmol/L [referral range (RR): 3.95 to 8.84 mmol/L] and hyperglobulinemia at 56 g/L (RR: 28 to 51 g/L). The CT scan showed a soft-tissue opacity consisting of a cyst in the orbit from the previously enucleated eye with a draining tract and a completed destruction of the nasal turbinates. Pseudomonas aeruginosa was cultured from nasal biopsies. Histopathologic analysis of the nasal tissue showed lymphocytic and neutrophilic rhinitis with edema. Revision surgery was carried out to remove the orbital cysts. Histopathologic analysis of the cyst in the left orbit revealed a distorted globe with almost all the ocular structures. Upon recheck a few weeks later, no discharge from the surgical site was observed. However, mild chronic discharge remained present in both nostrils. This is the first report of incomplete enucleation in a cat leading to chronic nasal signs. Removing the entire globe with the conjunctiva and lacrimal glands is important to minimize postsurgical complications. Key clinical message: This is the first case report of chronic nasal signs secondary to an incomplete enucleation in a cat. Key factors of the surgery include removal of the entire globe with the lacrimal gland, conjunctiva, and eyelid margin to prevent secondary complications.

Synergistic anti-infectious bronchitis virus activity of Phillygenin combined Baicalin by modulating respiratory microbiota and improving metabolic disorders

Phillygenin (PHI) and Baicalin (Bai) are the major chemical ingredients extracted from Forsythia suspensa and Scutellaria baicalensis, respectively. The mixture of Forsythia suspensa and Scutellaria baicalensis according to the theories of Traditional Chinese Veterinary Medicine, compounded formulation can effectively exert heat-clearing and detoxifying effect, but the synergistic anti-IBV activity of PHI combined with Bai was unclear. Here, the protection of PHI combined with Bai on avian infectious bronchitis virus (IBV) M41 infection and the change of respiratory microbiota and metabolomics profiles in broilers that infected with IBV were investigated. According to the experimental findings, the combination of PHI and Bai effectively alleviated broilers' slowing-growth weight and respiratory symptoms. This was accompanied by a reduction in viral copies and histopathological changes, as well as an increase of antiviral protein (G3BP1) level in tracheas and anti-IBV antibody levels in serum. In addition, 16s RNA sequencing revealed that IBV infection significantly changed respiratory microbiota composition at different taxonomic levels and respiratory metabolism composition in broilers. Interestingly, PHI combined with Bai modulated the composition of respiratory microfloras, especially the abundance of Firmicutes and Lactobacillaceae were upregulated, as well as the abundance of Proteobacteria was downregulated. The metabolomics results indicated that PHI combined with Bai involved in glucose, lipids, amino acids and nucleotide metabolism during IBV infection. In summary, PHI combined with Bai exhibited a synergistic effect on preventing infectious bronchitis (IB), with the protection being closely associated with the composition of respiratory microbiota and metabolites. Therefore, adding the mixture of PHI and Bai to the chicken drinking water is recommended to prevent and control IB in clinical.

Probiotics in milk replacer affect the microbiome of the lung in neonatal dairy calves

Introduction

Probiotics have been investigated for their many health benefits and impact on the microbiota of the gut. Recent data have also supported a gut-lung axis regarding the bacterial populations (microbiomes) of the two locations; however, little research has been performed to determine the effects of oral probiotics on the microbiome of the bovine respiratory tract. We hypothesized that probiotic treatment would result in changes in the lung microbiome as measured in lung lavage fluid. Our overall goal was to characterize bacterial populations in the lungs of calves fed probiotics in milk replacer and dry rations from birth to weaning.

Methods

A group of 20 dairy calves was split into two treatment groups: probiotic (TRT; N = 10, milk replacer +5 g/d probiotics; Bovamine Dairy, Chr. Hansen, Inc., Milwaukee, WI) and control (CON; N = 10, milk replacer only). On day 0, birth weight was obtained, and calves were provided colostrum as per the dairy SOP. On day 2, probiotics were added to the milk replacer of the treated group and then included in their dry ration. Lung lavages were performed on day 52 on five random calves selected from each treatment group. DNA was extracted from lavage fluid, and 16S ribosomal RNA (rRNA) gene hypervariable regions 1-3 were amplified by PCR and sequenced using next-generation sequencing (Illumina MiSeq) for the identification of the bacterial taxa present. Taxa were classified into both operational taxonomic units (OTUs) and amplicon sequence variants (ASVs).

Results

Overall, the evaluation of these samples revealed that the bacterial genera identified in the lung lavage samples of probiotic-fed calves as compared to the control calves were significantly different based on the OTU dataset (p < 0.05) and approached significance for the ASV dataset (p < 0.06). Additionally, when comparing the diversity of taxa in lung lavage samples to nasal and tonsil samples, taxa diversity of lung samples was significantly lower (p < 0.05).

Discussion

In conclusion, analysis of the respiratory microbiome in lung lavage samples after probiotic treatment provides insight into the distribution of bacterial populations in response to oral probiotics and demonstrates that oral probiotics affect more than the gut microbiome.