Billions of bacteria are part of the primate gastrointestinal tract, contributing to metabolic, autoimmune, and pathogen resistance. These bacteria are correlated to metabolic and autoimmune human diseases that are shown in western societies. Factors such as poor environment, stress, or antibiotic use can lead to dysbiosis, which is a microbial imbalance. This can cause the movement of bacteria, expansion of pathogens, and harmful bacteria to move into and out of the gastrointestinal tract. Overall microbial diversity can be lost due to dysbiosis. Understanding how diet and lifestyle can affect the composition of the gut microbiome is an important health issue to focus research towards.
A study of nonhuman primates in captivity was conducted to show the relationship between lifestyle and diet on gut microbial diversity to better understand primate conservation and human dysbiosis. The red-shanked douc and the howling monkey were the two species studied with a sample of different individuals from captive and wild environments. Both these species are folivorous, meaning a diet that is nutritionally poor and hard to digest. These species are hard to maintain in a captive environment due to the challenge of providing a wild-like diet. It was found that in captivity, the nonhuman primates have a loss in fiber, which in turn, a loss of native gut bacteria. Also, being in captivity, with the loss of native bacteria, they become colonized with two distinct bacteria, Prevoltella and Bacteroides. These are largely found in the human gut microbiome. The researchers confirmed this phenomenon in eight other captive environments that showed the same convergence pattern. By studying the most prevalent animal model to humans, other primates, can show environmental and diet behaviors that lead to a host of gastrointestinal diseases.