Effects of five carbohydrate sources on cat diet digestibility, postprandial glucose, insulin response, and gut microbiomes.

Cat obesity has become a serious problem that affects cats' lives and welfare. Knowing how to control obesity in pet cats and its mechanism is urgently needed. Here, by feeding 30 cats different diets for 28 d, we explored the effects of 5 cat foods with potato, sweet potato, cassava, rice, and wheat as the main carbohydrate sources on the glycolipid metabolism of pet cats. The results showed that dietary carbohydrate sources did not affect the normal growth performance and stool scores of cats. Notably, we found that the starch gelatinization degree of sweet potato and cassava cat food were higher than those of other groups, while the rice diets had the highest digestibility, but the difference was not significant (P > 0.05). Furthermore, cats fed cassava diets had lower postprandial glucose responses. The mean glucose value, maximum glucose value, AUC0-360 min, AUC≤30 min, and AUC≥30 min in the cassava group were lower than those in other dietary groups (P > 0.05). In addition, we found that the carbohydrate source had a minimal effect on serum biochemical immune indices, but the blood lipid indices, such as TG, TC, HDL, and LDL of cats fed the cassava diet were maintained at a low level compared with other groups (P > 0.05). In addition, diets with different carbohydrate sources affect the gut microbial composition, and sweet potato and cassava diets tend to increase the diversity of gut microbiota with a higher Shannon index and Simpson index. The abundance of Fusobacterium, Veillonella, and Actinobacillus was significantly higher in sweet potato diet-fed cats (P < 0.05), while the abundance of Delftia, Shinella, Rothia, and Hydrogenophage was highest in cassava diet-fed cats (P < 0.05). Collectively, this study revealed that cassava and sweet potato diets have a better effect on feeding value, controlling blood glucose and blood lipids, and improving the intestinal flora of pet cats, which is worth developing dietary formulations to alleviate pet obesity.