External ear canal mycobiome of some rabbit breeds.

The genus Malassezia is part of the normal skin mycobiota of a wide range of warm-blooded animals. In this genus, M. cuniculi is the only species described from rabbits. However, Malassezia species are rarely studied in lagomorphs. In the present study, the presence of Malassezia was assessed in samples from the external ear canal of healthy rabbits of different breeds. Cytological and culture techniques, Sanger sequencing, and Next-generation sequencing (NGS) were used to describe the ear mycobiota in the samples. Although no growth was observed in the cultured plates, cytological examination revealed the presence of round cells similar to those of Malassezia yeasts. For metagenomics analysis, the D1/D2 domain of the large subunit of the ribosomal DNA (LSU rDNA) was PCR amplified and the resulting reads were mapped against a custom-made cured database of 26S fungal sequences. NGS analysis revealed that Basidiomycota was the most abundant phylum in all the samples followed by Ascomycota. Malassezia was the most common genus presenting the highest abundance in the external ear canal. Malassezia phylotype 131 and M. cuniculi were the main sequences detected in the external auditory canal of rabbits. The study included both lop-eared and erect-eared rabbits and no differences were observed in the results when comparing both groups. This is the first attempt to study the external ear canal mycobiome of rabbits of different breeds using NGS. LAY SUMMARY: In the present study, the presence of Malassezia was assessed in samples from the external ear canal of healthy rabbits of different breeds. Cytological and culture techniques, Sanger sequencing, and Next-generation sequencing (NGS) were used to describe the ear mycobiota in the samples.