Feces metagenome Targeted loci environmental

This study investigated the role of the pineal gland in mediating the seasonal profile of the gut microbiota in Siberian hamsters (Phodopus sungorus). Siberian hamsters are photoperiodic mammals that display robust seasonal changes in behavior and physiology. These seasonal changes are largely driven by the pattern of melatonin release from the pineal gland. While the profile of the gut microbiota also changes by season, it was unclear whether these changes are driven by pineal signals. To test this, we placed pinealectomized and intact hamsters into long or short photoperiods for 8 weeks, and collected weekly fecal samples. The results of this study indicate that the pineal gland plays an important role in determining the seasonal profile of the microbiota. Thus, these results identify a novel neuroendocrine pathway by which a host regulates seasonal shifts in gut community composition and indicate a relationship between seasonal changes in the gut microbiota and seasonal physiological adjustments. These results represent an important advance in our understanding of the relationship between photoperiod, brain, microbiota, and physiology.