Effects of dietary fibers and their mixtures on short chain fatty acids and microbiota in mice guts.

Dietary fiber (DF) can be broken down into short-chain fatty acids (SCFAs) such as acetic, propionic and n-butyric acid by gut microbiota to obtain energy. Therefore, dietary fibers have effects on the balance of gut microbiota and the production of SCFAs. In the four-week feeding, mice were fed with four dietary fibers, including pectin, resistant starch (RS), fructo-oligosaccharide (FOS) and cellulose. The results showed that the mice body-weight gain was the smallest (7.0 ± 2.3 g) when the mixture of RS-FOS-cellulose was ingested, followed by the mixture of RS-cellulose (7.2 ± 3.5 g) and FOS-cellulose (8.3 ± 2.5 g). Ingestion of the mixture of pectin-FOS-cellulose, RS-FOS and RS-FOS-cellulose can respectively increase the diversity of the gut microbiota with 12, 11 and 11 terminal restriction fragments (TRFs) detected (digested by Hha I). The maximum amount of total SCFAs were produced by the mixture of FOS-cellulose (5.504 ± 0.029 μmol mL(-1)), followed by pectin-FOS-cellulose (3.893 ± 0.024 μmol mL(-1)) and pectin-RS-FOS-cellulose (3.309 ± 0.047 μmol mL(-1)). In conclusion, the addition of DFs (pectin, RS, FOS and cellulose), in single or mixture pattern, can exert different effects. An amount of 10.7% of single DF in the diet cannot be conducive to the balance of gut microbiota after ingestion for a long time, however, it can help with body weight loss like the mixtures of DFs in this study; FOS is a very important component in the mixture of DFs for both the balance of the gut microbiota and the production of SCFAs.