Anaerobic Fungi in Gorilla (Gorilla gorilla gorilla) Feces: an Adaptation to a High-Fiber Diet?

Many studies have demonstrated the importance of symbiotic microbial communities for the host with beneficial effects for nutrition, development, and the immune system. The majority of these studies have focused on bacteria residing in the gastrointestinal tract, while the fungal community has often been neglected. Gut anaerobic fungi of the class Neocallimastigomycetes are a vital part of the intestinal microbiome in many herbivorous animals and their exceptional abilities to degrade indigestible plant material means that they contribute significantly to fermentative processes in the enteric tract. Gorillas rely on a highly fibrous diet and depend on fermentative microorganisms to meet their daily energetic demands. To assess whether Neocallimastigomycetes occur in gorillas we analyzed 12 fecal samples from wild Western lowland gorillas (Gorilla gorilla gorilla) from Dzanga-Sangha Protected Areas, Central African Republic, and subjected potential anaerobic fungi sequences to phylogenetic analysis. The clone library contained ITS1 fragments that we related to 45 different fungi clones. Of these, 12 gastrointestinal fungi in gorillas are related to anaerobic fungi and our phylogenetic analyses support their assignment to the class Neocallimastigomycetes. As anaerobic fungi play a pivotal role in plant fiber degradation in the herbivore gut, gorillas might benefit from harboring these particular fungi with regard to their nutritional status. Future studies should investigate whether Neocallimastigomycetes are also found in other nonhuman primates with high fiber intake, which would also benefit from having such highly efficient fermentative microbes.