The current gut microbiome research relies on the fecal microbiome under the assumption that the fecal microbiome represents the microbiome of the entire gastrointestinal (GI) tract. However, there have been growing concerns about using feces as a proxy to study the gut microbiome. Here, we comprehensively analyzed the composition of microbiome and metabolites in the feces and at 14 different locations of GI tracts of genetically homogenous sibling pigs to evaluate the validity of using feces as a proxy to the whole gut microbiome. The composition of intestinal microbes constituting the gut microbiome at each intestinal content and feces and their metabolic compositions were thoroughly investigated through metagenome sequencing and an ultraperformance LC-MS/MS, respectively. The fluctuation in the composition of the microbiome in the stomach and the small intestine became stabilized from the large intestine to feces and was able to be categorized into 3 groups. The taxonomic α-diversities measured by ACE (abundance-based coverage estimator) richness and Shannon diversity indicated that the microbiome in the large intestine was much more diverse than those of the small intestine and feces. The highly independent intestinal microbes in the stomach and the small intestine became flourished in the large intestine and converged into a community with tightly connected networks. β-Diversity analyses by NMDS plots, PCA, and unsupervised hierarchical clustering all showed that the diversities of microbiome compositions were lowest in feces while highest in the large intestine. In accordance with fluctuation of the composition of gut microbiome along with the GI tract, the metabolic composition also completely differed in a location-specific manner along with the GI tract. Comparative analysis of the fecal microbiome and metabolites with those of the whole GI tract indicated that fecal microbiome is insufficient to represent the whole gut microbiome.
The current gut microbiome research relies on the fecal microbiome under the assumption that the fecal microbiome represents the microbiome of the entire gastrointestinal (GI) tract. However, there have been growing concerns about using feces as a proxy to study the gut microbiome. Here, we comprehensively analyzed the composition of microbiome and metabolites in the feces and at 14 different locations of GI tracts of genetically homogenous sibling pigs to evaluate the validity of using feces as a proxy to the whole gut microbiome. The fluctuation in the composition of the microbiome in stomach and the small intestine became stabilized from the large intestine to feces and were able to be categorized into 3 groups. The highly independent intestinal microbes in stomach and the small intestine became flourished in the large intestine and converged into a community with tightly connected networks. Comparative analysis of the gut microbiome at each location suggested that fecal microbiome is insufficient to represent the whole gut microbiome.
A 10-year-old castrated male miniature poodle dog with diabetes mellitus was presented for a week history of blepharospasm and epiphora in the right eye. The spontaneous chronic corneal epithelial defect (SCCED) was diagnosed, and a bandage contact lens was applied following corneal debridement with sterile cotton-tip applicators. In 1 week, SCCED was improving uneventfully, though an annular pattern of intracorneal hemorrhage was observed. The contact lens was removed and the intracorneal hemorrhage resorbed in 4 weeks. To the author's knowledge, this is the first report of presumed contact lens-induced intracorneal hemorrhage characterized by an annular pattern in a dog.
A fledgling feral pigeon with systemic protozoal infection was referred with corneal protrusion in the right eye after being treated for a corneal ulcer for 12 days. Ophthalmic examination revealed a corneal bulla covering almost the entire central cornea and preventing the eyelids from closing. Gelatinous corneal stroma with numerous heterophils surrounding the corneal bulla was also detected on cytologic examination. Bullous keratopathy and melting keratitis in the right eye were diagnosed. Temporary tarsorrhaphy with topical eye drops was prescribed for a week; however, the bulla persisted. A modified nictitating membrane flap was created under general anesthesia and maintained for 2 weeks. The corneal bulla resolved, and corneal thickness was restored. The pigeon was presented again with recurrence of the corneal bulla in the right eye after 45 days. Alternative surgical options were recommended; however, the pigeon was euthanized because the protozoa‐induced intra‐oral and intra‐aural masses caused malformation of the beaks, which made voluntary feeding impossible.
Objective
To report the corneal toxicity of erlotinib in dogs.
Animal studied
A 13‐year‐old castrated male Maltese dog.
Results
A dog with lung cancer presented with a month‐long history of mucoid discharge and blepharospasm in both eyes. Corneal ulcerations with stromal thinning were diagnosed in both eyes, which were refractory after 2 weeks of treatment with topical antibiotics and artificial tears. The dog was orally administered erlotinib (Tarceva®) by his owner for 2 months to treat his lung cancer. Urgent withholding of erlotinib was recommended, and after 2 weeks of discontinuation, the corneal defects resolved; however, corneal thinning remained until the six‐month follow‐up.
Conclusions
To the best of author's knowledge, this is the first report in the veterinary literature that describes bilateral corneal ulcers associated with erlotinib administration in a dog.
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