Abstract: Objective: To explore the effect of various dosage of food-grade κ-carrageenan on the risk of colitis and the accumulation of body fat in obese mice. Methods: After feeding C57BL/6Cnc male mice with a low-fat or high-fat diet for 5 weeks, the mice fed with the high-fat diet was 22% heavier than those fed with the low-fat diet, indicating that an animal of obesity model was successfully constructed. The mice were divided into seven groups, including normal control (NC), high-fat diet (HFD) model and HFD + 0.05% (H0.05%), 0.5% (H0.5%), 1% (H1%), 2.5% (H2.5%) or 5% (H5%) carrageenan groups. After feeding for 6 weeks, the mice were sacrificed to examine indicators related to colon inflammation and body fat accumulation. Results: Disease activity index (DAI), myeloperoxidase activity and the relative mRNA expression of inflammatory factors in the colon, and colonic physiological structure were not significantly different among all groups (P > 0.05). The secretion of prostaglandin E2 in the colon of mice in the H1% and H2.5% groups decreased by 13.94% and 20.75%, respectively compared to the HFD group (P < 0.05). The body mass, body fat percentage and epididymal adipocyte size of mice in the H5% group decreased by 10.51%, 37.67% and 31.59%, respectively compared with the HFD group (P < 0.05). Conclusion: Dietary addition of 0.05%–5% food-grade κ-carrageenan had no risk of inducing colitis in obese mice, and 5% carrageenan inhibited the accumulation of body fat.

Key words: food-grade carrageenan; dosage; obese; colitis; body fat accumulation