Many herbivorous small mammals are limited by low-quality food and body size, and they often cannot get enough energy and nutrients to meet their metabolic and nutritional needs. Coprophagy, a popular behavior to eat feces of their own and others, can help some herbivores rodents reabsorb the nutrients, and provide some essential amino acids, vitamin B and vitamin K as well.

Recently, researchers from the Animal Physiological Ecology Group of the Institute of Zoology, Chinese Academy of Sciences discovered that the coprophagy of Brandt's vole could regulate metabolism, neurochemistry, and cognitive behavior by changing gut microbiota.

In this study, by preventing the behavior of coprophagy, the researchers found that the coprophagy prevention influence the community structure of the gut microbiota in voles. Bacteroidetes increased while Firmicutes decreased, however, the structure and composition of gut microbiota will also be restored after the animals recover their coprophagy.

They also found that during coprophagy prevention, voles were in a state of negative energy balance, voles decrease their body weight and increase food intake and changed the hormone and neurotransmitter levels. Further, they tested the memory of voles after preventing of coprophagy by Y-maze, and results showed that their memory was damaged.

In order to further explore whether the memory impairment caused by coprophagy prevention is related to the changes of gut microbiota, they targeted the short-chain fatty acids (SCFAs), the main metabolites of the gut microbiota, and they made artificial supplement of acetate to the voles which were prevented of coprophagy. They found that daily acetate administration was able to reverse some of the coprophagy prevention-induced changes in microbiota composition, metabolism, neurochemistry and cognitive behavior.

All together, coprophagy help to maintain the stable gut microbiota, promote microbial metabolites, maintain host energy balance, and benefit the host cognitive performance, according to the researchers.

This is another finding demonstrating the function of gut microbiota in regulating host metabolism in wild small mammals, after two other papers showing that huddling improves gut microbial community and confers host energy benefit to defense cold and gut microbiota-norepinephrine crosstalk regulates thermogenesis during cold acclimation, from the lab of Prof. WANG Dehua.

This research was supported by the National Natural Science Foundation of China and the Natural Science Foundation of Beijing.

Coprophagy affects the gut microbiota and cognitive behavior of Brandt's voles. (Image by IOZ)