*3.4. Effect of GCP on the SCFAs of Normal Mice*

Due to the glycoside bonds between monosaccharides and their complex structure, most polysaccharides are resistant to saliva and gastric and small intestinal juices, which are further utilized by gut microbiota to produce SCFAs [18,32]. As illustrated in Figure 2, the concentrations of SCFAs in the control group were significantly lower than in experimental groups (*p* < 0.01). After administration of 400 μg/mL GCP for 28 days, the acetate concentration in the cecum contents of mice increased from 23.85 ± 1.37 μmol/g to 42.77 ± 1.29 μmol/g, the propionate concentration increased from 10.23 ± 0.78 μmol/g to 20.03 ± 1.44 μmol/g, the butyrate concentration increased from 7.15 ± 0.35 μmol/g

to 12.06 ± 0.51 μmol/g, and the total SCFAs increased from 41.23 ± 0.86 μmol/g to 74.86 ± 2.07 μmol/g. SCFAs could inhibit the growth and reproduction of pathogenic bacteria by reducing the acidity of the intestinal environment, but could also produce a positive systematic physiological effect on the host via regulating the innate and adaptive immune systems and intestinal permeability [33]. Furthermore, SCFAs may also be conducive to losing weight by promoting satiety [34], especially acetate, thus explaining the reduction in body weight gain caused by GCP in Table 1. Many factors affect the utilization of polysaccharides by gut microbiota, such as linkage mode, chain type, molecular weight, sulfate content, etc. [35]. In future work, we will investigate the effect of the GCP's structure on the gut microbiota utilization.

**Figure 2.** Effect of GCP on the concentrations of acetate, propionate, butyrate and total SCFAs in the cecum of mice (*n* = 10). (**A**) Acetate, (**B**) propionate, (**C**) butyrate, (**D**) total SCFAs. CON: control group. Significance was determined through ANOVA, \*\* *p* < 0.01.
