Cold Exposure during the Active Phase Affects the Short-Chain Fatty Acid Production of Mice in a Time-Specific Manner

Abstract

Chronic or acute ambient temperature change alter the gut microbiota and the metabolites, regulating metabolic functions. Short-chain fatty acids (SCFAs) produced by gut bacteria reduce the risk of disease. Feeding patterns and gut microbiota that are involved in SCFAs production are controlled by the circadian clock. Hence, the effect of environmental temperature change on SCFAs production is expected depending on the exposure timing. In addition, there is limited research on effects of habitual cold exposure on the gut microbiota and SCFAs production compared to chronic or acute exposure. Therefore, the aim was to examine the effect of cold or heat exposure timing on SCFAs production. After exposing mice to 7 or 37 °C for 3 h a day at each point for 10 days, samples were collected, and cecal pH, SCFA concentration, and BAT weight was measured. As a result, cold exposure at ZT18 increased cecal pH and decreased SCFAs. Intestinal peristalsis was suppressed due to the cold exposure at ZT18. The results reveal differing effects of intermittent cold exposure on the gut environment depending on exposure timing. In particular, ZT18 (active phase) is the timing to be the most detrimental to the gut environment of mice.

Effects of ambient temperatures between 5 and 35 °C on energy balance, body mass and body composition in mice

“…The increase in metabolism as ambient temperature fell below the LCT was correlated with increased levels of T3, expansion of the BAT mass, increases in BAT mitochondrial protein, BAT COX activity and direct measures of non-shivering thermogenesis. These observations all support extensive previous work showing thermogenesis after about 10 days of cold exposure is provided predominantly by elevated heat production in BAT [ 26 , [76] , [77] , [78] ]. Our work shows that these responses are closely calibrated to the exact levels of cold, and the thermoregulatory requirements to sustain body temperature.…”

The gut microbiome: a core regulator of metabolism

“…This evidence suggests that increasing SCFAs in the body might be metabolically beneficial. In addition to the intake of non-digestible polysaccharides, physical activity (Magzal, et al 2022) and cold stimuli (Ichikawa, et al 2021)…”

“…This evidence suggests that increasing SCFAs in the body might be metabolically beneficial. In addition to the intake of non-digestible polysaccharides, physical activity ( Magzal et al 2022 ) and cold stimuli ( Ichikawa et al 2021 ) are implicated in SCFA production. Prior attempts have been made to ameliorate metabolic diseases using SCFA-related interventions.…”