Harmon, D. L., Yamka, R. M. and Elam, N. A. 2004. Factors affecting intestinal starch digestion in ruminants: A review. Can. J. Anim. Sci. 84: 309-318. The process of starch assimilation in the ruminant is complex and remains an avenue by which increases in production efficiency can be gained. Ruminal starch digestion is typically 0.75-0.80 of starch intake. Starch that escapes fermentation and flows to the small intestine may be more resistant to enzymatic digestion and on average 0.35-0.60 of starch entering the small intestine is degraded there. Of the fraction that escapes small intestinal digestion an additional 0.35-0.50 is degraded in the large intestine. This suggests that limitations to small intestinal starch digestion do exist. This review summarizes available information describing the digestive and absorptive processes occurring in the small intestine with an emphasis on nutritional factors that influence these processes. A review of experiments measuring small intestinal starch digestion indicates that small intestinal digestion is either highly variable or poorly determined whereas ruminal and large intestinal digestion are much more clearly described. These data indicate that improvements in methodologies are needed before we can accurately describe processes occurring in the small intestine and formulate diets to optimize site of starch digestion. L'amidon qui échappe à la fermentation pour passer dans l'intestin grêle pourrait résister davantage à une digestion enzymatique et 35 à 60 % de cet amidon y est dégradé. Sur la fraction qui sort intacte de l'intestin grêle, 35 à 50 % sont dégradés dans le gros intestin. Tout laisse croire que la digestion de l'amidon dans l'intestin grêle a ses limites. L'article que voici résume l'information disponible sur les mécanismes de digestion et d'absorption qui surviennent dans l'intestin grêle, en mettant l'emphase sur les paramètres nutritionnels qui influent sur ces mécanismes. L'analyse des expériences jaugeant la digestion de l'amidon dans l'intestin grêle indique que cette dernière varie considérablement ou est mal évaluée, tandis qu'on possède des données nettement plus précises sur la digestion dans le rumen ou le gros intestin. Les données laissent croire que les méthodes devraient être améliorées avant qu'on puisse décrire avec précision les processus qui surviennent dans le petit intestin et qu'on formule des régimes en vue d'optimiser la digestion de l'amidon.
Mots clés: Ruminants, amidon, glucose, intestin grêle, digestionThe ruminant digestive system provides the powerful advantage of pregastric fermentation that enables the use of structural carbohydrates and the production of microbial protein to meet the needs of the host. This complexity of ruminant digestion also offers a challenge towards optimizing nutrient supply for the host. Despite the advantages for use of structural carbohydrates, the system is not designed for use of nonstructural carbohydrates. The pregastric fermentation results in fermentation losses of 13-18% of gross energy ...
Dietary fortification with fish oils rich in DHA and possibly other nutrients implicated in neurocognitive development following weaning improved cognitive, memory, psychomotor, immunologic, and retinal functions in growing dogs.
Eight mature female dogs (18.0 +/- 0.2 kg) were used in a replicated 4 x 4 Latin square experiment to determine the feeding value of low-ash poultry meal (PM) in a complete food fed to dogs. All foods contained graded concentrations of PM (10.4 to 32.5% DM), resulting in foods that were 10, 15, 20, and 25% CP. Daily DMI averaged 284 +/- 14 g/d. An increase in PM resulted in an increase in fecal moisture from 44.7 to 55.1% (linear; P < 0.01), and fecal DM output increased from 24.8 to 31.6 g/d (linear; P < 0.05). Ileal DM flow increased from 27.1 to 40.7 g/d (linear; P < 0.01). Small intestinal DM digestibility decreased from 90.4 to 86.1% (linear; P < 0.01) and total-tract DM digestibility decreased from 91.2 to 89.4% (linear; P < 0.01) as PM increased. Large intestinal DM digestibility increased from 8.4 to 21.1% with increasing PM (linear; P < 0.05). Fecal excretion of CP increased from 5.6 to 10.0 g/d (linear; P < 0.01) and ileal flow of CP increased from 6.9 to 15.6 g/d (linear; P < 0.01) as PM increased. Small intestinal CP digestibility was unaffected with treatment (P > 0.05). Large intestinal CP digestibility increased from 21.6 to 37.1% (linear; P < 0.05) with increasing PM. Total-tract CP digestibility increased from 81.0 to 86.6% (linear; P < 0.01) as PM increased. Arginine had the highest overall digestibility ranging from 88.5 to 91.3%, whereas cysteine had the lowest digestibility, ranging from 67.1 to 71.4%. These data indicate that PM is a highly digestible protein source for canine foods with inclusions of 10.4 to 32.5% of DM.
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