During the reporting period, the Researcher first got specific training in laboratory techniques and bioinformatics at the partner organization: the Institute for Genomic Biology (IGB), within the University of Illinois, USA. The Researcher has successfully analyzed 168 fecal samples of two wild primates living in the Udzungwa Mountains of Tanzania for bacterial, fungal and helminthes diversities and composition. Bioinformatics and statistical analyses were performed at the beneficiary host institute (FEM) where the Researcher devoted most of the time to analyzing and writing up the results obtained. Despite the fact that some analyses are still on-going, especially those referring to the interactions between biota, among the key results we achieved is the first comprehensive assessment of gut biota diversity (i.e. bacteria, fungi and parasitic worms, simultaneously) of tropical primates living in natural conditions.
Although the two selected primates are phylogenetically related, bacterial and fungal composition of their guts was clearly distinct, probably as a result of their dietary habits (e.g. red colobus are folivorous and baboons are omnivorous). That red colobus had a higher bacterial gut diversity than that of yellow baboons is also found in humans with a vegetarian vs omnivorous diets. Similarly, leaf-eating red colobus monkeys presented higher fungal richness than the omnivorous baboons, consistent with previous findings indicating that hosts with high gut fungal richness might be more efficient in breaking down plant fibers.
In addition, despite the short geographical distance separating the intact and well protected forest from the degraded one, individuals of the same primate species present unique gut biota compositions in each forest type, especially bacteria and fungi. However, although intact habitats are expected to offer their animal inhabitants a more diverse diet, the WILDGUT results support this hypothesis only for the arboreal and strictly leaf-eating red colobus monkey. We did not find the same association within the omnivorous, crop-raiding baboon. We conclude that due to the rapid conversion of tropical forest in agricultural croplands, baboons living in proximity to human settlements have altered their behavioural strategies by feeding on human food waste and cultivations. By widening their dietary choices, baboons most likely increased their bacterial richness and consequently changed their gut biota composition. However, this increase may not be entirely positive; for example, we observed that baboons living in degraded habitats had an enrichment of bacterial genera such as Sarcina and Prevotella which are generally associated with consumption of sugar-rich food and potentially linked to chronic gut inflammatory conditions and implicated in gut diseases.
Also for parasitic worms, another important component of the gut, we found a reduction of parasite diversity in animals living the degraded forests compared to those from intact forests. This result confirms those found for bacteria, and strengthens the idea that habitat changes also promote biodiversity loss at a micro scale. Thus, the need for further investigations on the health impacts of changes in the different components of the gut biota and their interactions on conservation is ever more urgent.
