The regulatory effect of fermented black barley on the gut microbiota and metabolic dysbiosis in mice exposed to cigarette smoke.

Smoking is a global public health event that can cause oxidative stress and gut microbiota dysbiosis and is related to the occurrence of diseases such as cancer and respiratory system disease. We previously found that fermented black barley was rich in antioxidative components such as polyphenols and flavonoids and regulated gut microbiota dysbiosis. In the present study, the protective effects of fermented black barley on cigarette smoke-induced damage, such as lung, reproduction organ injury, gut microbiota and metabolic dysbiosis, were investigated. Fermented black barley (100 μL/10 g·BW per day, containing 1 × 10 CFU/mL Lactobacillus) was administered orally to male ICR mice that were regularly exposed to cigarette smoke (one time a day, 15 cigarettes each time, 30 min/time). The intervention lasted continuously for 12 weeks. The results showed that compared to the group exposed only to cigarette smoke, fermented black barley treatment alleviated the pathological damage to lung and testis tissues and significantly increased the total sperm motility and antioxidative capacity of the lung. Fermented black barley also regulated the intestinal microbiome diversity; reduced the relative abundances of Lactobacillus, Turicibacter and Bifidobacterium; and increased the relative abundances of Oscillospira and Ruminococcus at the genus level. Furthermore, the metabolic profile was investigated via analysis of the abundances of fecal and hepatic metabolites, and it was shown that fermented black barley treatment alleviated the metabolic dysbiosis of lipids, amino acids, and the biosynthesis of steroid hormones (such as dehydroepiandrosterone sulfate, etc.) induced by cigarette smoking, which approached normal conditions. These regulatory effects may partially elucidate the beneficial role of fermented black barley in alleviating the harmful effects of cigarette smoking. In summary, supplementation with fermented cereal food may be a helpful way to ameliorate cigarette smoking-induced damage.