This study aimed to evaluate the fermentation in the large intestine of indigestible dietary protein sources from animal, insect, and plant origin using an in vitro model of the pig's gastrointestinal tract. Protein sources were used raw and after a cooking treatment. Results showed that the category of the ingredient (meats, insects, or grain legumes) exerts a stronger impact on enzymatic digestibility, fermentation patterns, and bacterial metabolites such as short-chain fatty acids (SCFA) and hydrogen sulfide (H2S) than the cooking treatment. The digestibility and the fermentation characteristics of insects were more affected by the cooking procedure than the other categories. Per gram of consumed food, ingredients from animal origin, namely, meats and insects, were associated with fewer fermentation end-products (gas, H2S, SCFA) than ingredients from plant origin, which is related to their higher small intestinal digestibility.
Keywords: hydrogen sulfide; in vitro method; pig; protein fermentation; short-chain fatty acid.