Effects of protein source and cooking procedure on intestinal microbiota and on fermentation end-products in rats

Animal and plant proteins are major proteins sources in the human diet. After their enzymatic degradation in the upper gastro-intestinal tract, the undigested fraction of these proteins is available for fermentation by the microbiota of the large intestine leading to the production of short-chain fatty acids (SCFA), branched-chain fatty acids (BCFA), ammonia, biogenic amines, sulphur metabolites, phenols and indoles. As some of these compounds have genotoxic and cytotoxic effects, protein fermentation is considered as detrimental to the host’s epithelial health. BCFA are usually used as a marker of intestinal protein fermentation. We studied in vivo the impact of proteins from animal and plant origin, raw or after a cooking procedure, on the composition of gut microbiota and on fermentation end-products. Weanling rats were used as models of the human gut microbiota. Eight experimental diets were formulated with beef meat (Longissimus dorsi), chicken meat (Pectoralis major), white pea beans (Phaseolus vulgaris), soybeans (Glycine max), used raw and cooked, as sole source of protein in the diet. One casein diet was used as control. All diets, formulated to contain 15% of raw protein, were given to seven rats for four weeks. After euthanasia, caecal contents were collected. Pyrosequencing analyses (Roche 454 GS Junior Genome Sequencer) were performed to study the microbial composition. SCFA and BCFA were measured using HPLC (Waters 2690). Microbial composition in the caecum is associated to the type of dietary protein and to the cooking procedure applied. The proportion of BCFA in the caecal content is mainly affected by the type of protein. So BCFA represent respectively 04-06% and 35-44% of total SCFA with diets based on plant and on animal proteins. In conclusion, both the type of protein and the cooking procedure could impact the gut microbiota in terms of composition and of fermentative capacity.Crédit aux Chercheurs 1.5180.1

Digestibilité, fermentation et impact sur la santé intestinale de protéines animales et végétales consommées par l'Homme

Crédit aux chercheurs 1.5180.1

In vitro evaluation of fermentation characteristics of two types of insects, as potential novel protein feeds for pigs

peer reviewedCrédit aux Chercheurs 1.5180.1

Digestibilité et fermentation intestinale de deux sources de protéines animales, soumises ou non à un traitement thermique, chez le rat en croissance

peer reviewedCrédit aux chercheurs 1.5180.1

In vitro evaluation of fermentation characteristics of two types of insects as potential novel protein feeds for pigs

Novel protein sources such as insects are suggested for pig nutrition. Protein availability might be impacted by the nature of the insect and by the thermal treatment applied to sanitize this ingredient. Their influence on protein availability and colonic fermentation is unknown. Plant proteins (beans, lentils, peas, and soybean, raw and vapor cooked) were compared to adult house crickets (Acheta domesticus) and mealworm larvae (Tenebrio molitor) that had been autoclaved, oven cooked (150 and 200°C), or used raw. Ingredients were run in an in vitro model of the pig gastrointestinal tract combining enzymes to simulate digestion in the stomach and the small intestine and subsequent fermentation by fecal microbes to simulate hindgut fermentation. In vitro crude protein disappearance (IVCPD) of insects decreased with oven cooking at 150°C or autoclaving (P 0.05), except for soybean. IVCPD of raw mealworms (0.726) equaled that of the best plants (0.725 to 0.763) while crickets were less digestible (P < 0.01). Consequences on fermentation metabolites were lower propionate (P < 0.01) and branched-chain fatty acids (BCFA; P < 0.05) molar ratio in raw insects against oven-cooked or autoclaved insects. Both insect sources displayed greater BCFA (P < 0.01) and lower propionate (P < 0.01) than plants. Crickets produced 50% as much BCFA as mealworms (P < 0.01). In conclusion, feeding insect-sourced protein requires a careful choice of the species as well as the thermal treatment to avoid possible detrimental consequences on digestibility and intestinal health in pigs

Cooking Has Variable Effects on the Fermentability in the Large Intestine of the Fraction of Meats, Grain Legumes, and Insects That Is Resistant to Digestion in the Small Intestine in an in Vitro Model of the Pig’s Gastrointestinal Tract

peer reviewedThis 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.This research was supported by the Fund for Scientific Research (FNRS, Brussels, Belgium − Research Credit 1.5180.12). The research was performed within the framework of the collaborative Food4Gut excellence research program of the Walloon Government