Probiotic Microbes Sustain Youthful Serum Testosterone Levels and Testicular Size in Aging Mice
a. Gross appearance of outbred Swiss male mice with oral Lactobacillus reuteri treatment at 12 months of age. Testes of L. reuteri-fed mice are larger compared to control mice. b–e. Results of statistical analyses of testes weight at different time-points after starting treatment, including the (b) 5, (c) 7, (d) 9 and (e) 12 months of age time-points. L. reuteri consistently increased testicular weight in both control- and new western-diet-fed mice compared to age- and diet-matched controls. Dietary supplementation with L. reuteri, but not with E coli K12, increased testicular weight in control-diet-fed mice at age 7 months when compared to age- and diet-matched controls (c). Numbers on the y-axis of bar graphs correspond to the mean±SEM of testes weight or the testicular weight; *p<0.05, **p<0.001.