Fig. 2

Physiological characteristics of Abx-treated old mice. A Schematic illustration of FMT to antibiotics-treated 12-month-old mice (xOld). The matrix describes two donor groups: O, old at 12 months; Y, young at 5 weeks. The recipient mice were designated as xOld^O (n = 5) and xOld^Y (n = 6). After a week of acclimation followed by a week of antibiotic treatment, FMT was repeated 16 times for 8 weeks. B Relative abundance of the gut microbiota in xOld during FMT. Samples were grouped by the fecal donor and ordered by collection time. C Linear discriminant analysis effect size of samples between xOld^O and xOld^Y at week 8. _una, unassigned; _unc, uncultured. D Body weight changes in xOld during FMT. Mice were housed in a SPF facility and weighed twice a week during FMT treatment. Results are represented as mean ± SD. E Relative organ weight in xOld after FMT. Each group of mice was euthanized after FMT and the heart, brain, liver, spleen, kidney, BAT, and WAT were weighed. F Blood chemistry analysis of serum from the treatment groups. G Passive avoidance test. Total time in the illuminated chamber was recorded as training time on day 1 and retention time was recorded on day 2. H Grip strength of contralateral forelimb. I Average diameter of muscle fiber. J Average number of stratum corneum layers. K Skin hydration (left) and TEWL (right) values. Box and whiskers. Student’s t test. *P < 0.05, ** P < 0.01, *** P < 0.001, and **** P < 0.0001