In vitro simulated canine and feline gastrointestinal digestion of fructooligosaccharides and isomaltooligosaccharides and their effects on intestinal microbiota

This study aimed to investigate the effects of fructooligosaccharides (FOS) and isomaltooligosaccharides (IMO) in simulated canine and feline gastrointestinal digestion, as well as on growth and metabolism of intestinal microorganisms in vitro. Changes in the composition of FOS and IMO before and after simulated canine and feline gastrointestinal digestion were analyzed using high performance liquid chromatography (HPLC). In vitro fermentation of intestinal microorganisms was conducted to assess strain growth, pH of the fermentation broth, and lactic acid content. The results revealed that IMO did not result in changes in the chemical composition in the juice of simulated canine and feline gastrointestinal digestion, while degradation of FOS was observed. Following simulated gastrointestinal digestion, the primary components of both FOS and IMO were identified as isomaltose. Furthermore, it was observed that FOS and IMO digested in the simulated canine and feline gastrointestinal fluid could be utilized by some intestinal microbes. The pH of Lactobacillus acidophilus and Bifidobacterium animalis fermentation system decreased significantly (P < 0.001), and the lactic acid content increased significantly (P < 0.001). Notably, the biomass of Escherichia coli (P < 0.01) and Clostridium perfringens (P < 0.001) increased, suggesting the importance of combining prebiotics and probiotics to inhibit the growth of pathogenic bacteria. Moreover, in simulated intestinal fluid, FOS played a prebiotic role for both dogs and cats, while IMO played a more prominent prebiotic role for cats than dogs. These findings highlight that FOS and IMO could serve as potential prebiotics, each with varying degrees of utilization, thus offering valuable insights for the development of healthy foods for dogs and cats.