The Effect Of Two Fasting Regimes On The Gut Microbiome In Mice

Objective: Intermittent fasting(IF),also known as time-restricted fasting is a popular type of dietary intervention,typically ranging from 16 to 24 hours per day,repeated for several weeks to six months.A number of studies have shown that IF intervention is beneficial on weight loss,lowering blood sugar,improving blood pressure and blood lipids,and prolonging life expectancy.However,the underlying mechanism is still unclear,but may be related to changes in gut microbiota.An in-depth understanding of the action and function of microbiome during IF would be helpful for discovery and identification of functional bacteria,thereby providing preliminary data for the exploration and utilization of bioactive peptides derived from intestinal probiotics.Method: Based on the two commonly used IF intervention strategy,C57BL/6J mice were divided into two groups: namely 16 hours fast(daily fasting)and 24 hours fast(alternate-day fasting),with subgroup using day and night alternate fast mode of intervention.There are a total of five groups(n=16): 16-hour daytime fasting(D-DF),16-hour night fasting(N-DF),24-hour daytime fasting(N-ADF),24-hour night fasting(N-ADF),and non-fasting control(Ad libitum,AL).The body weight and food intake were weighed during fasting.After fasting,fasting blood glucose was measured,and feces,blood and tissue were collected.Subsequently,feces of each group were subjected to bacterial 16 S r RNA gene sequencing.Result: After IF,the cumulative food intake was significantly reduced in all experimental groups compared to AL.Body weight did not significantly differ between D-DF and AL group either before or after fasting,while it was reduced in N-DF group.However,decreased fasting blood glucose was observed in D-DF only.Furthermore,the shift of the microbiome composition was seen in each experimental group,with Bacteroidota phyla and Faecalibaculum genera being decreased,and Firmicutes phyla,Ligilactobacillus genera and Lactobacillus?murinus being increased.Conclusion: This study showed that fasting reduced the cumulative feeding and body weight of mice in the 24-hour fasting group.In addition,fasting also altered the microbiome structure of the mice,increasing the abundance of intestinal protective bacteria,decreasing the relative abundance of harmful bacteria.This study preliminarily proved that the start time of fasting had a greater impact on the 16-hour fasting group but had a smaller impact on the 24-hour fasting group.The effect was more diverse in the 24-hour fasting group.Fasting starting from the day or night was also different in changing the gut microbiota.Overall,both fasting duration and time are extremely important.This study provides new insights into intermittent fasting effect.