The fountain of youth
lurking inside intestines:
Microbiota.
Gut microbes are important for digestion, nutrition and immunity, and gut microflora may impact on life expectancy. Young African turquoise killifish have diverse microbial communities but this diversity decreases over time. By feeding middle-aged killifish the microbes from younger fish, Smith et al (2017) found that the older fish lived longer and were more active in later life. Manipulating gut microbe composition may therefore be a way of delaying diseases related to ageing.