TRIENNIAL GROWTH SYMPOSIUM: Effects of polymeric carbohydrates on growth and development in pigs1

Abstract

Polymeric carbohydrates, starch and nonstarch polysaccharides (NSP), quantitatively represent the largest portion of the diets for pigs and are, therefore, the largest energy contributor. The 2 types of polysaccharides, however, have different fates and functions in the gastrointestinal tract and lead to different metabolites upon digestion. Pancreatic and mucosal enzymes in the small intestine break down the majority of starch, whereas NSP primarily are degraded by the microflora in the large intestine. Starch degradation leads to the release of glucose, which is absorbed by an active absorption process that triggers the release of insulin from the pancreas, whereas the fermentation of NSP to short-chain fatty acids (SCFA; i.e., acetate, propionate, and butyrate) occurs at a slower and more constant rate and with SCFA being absorbed by passive diffusion. Type and amounts of polymeric carbohydrates influence growth and development through different mechanisms. First, the proportion of starch to NSP plays an important role for the content of available energy (i.e., DE, ME, and NE); available energy relative to protein is crucial for performance and carcass quality. Second, the proportion of starch to NSP will influence rate and type of metabolites (i.e., glucose vs. SCFA) deriving from carbohydrate assimilation. Third and finally, the type of starch (i.e., types A, B, and C) and soluble NSP will influence the release of insulin, the hormone that facilitates nutrient uptake by tissues, organs, and cells, and thus plays a critically essential role in protein synthesis and muscle growth, as well as lipid synthesis and adipose tissue growth. In conclusion, polymeric carbohydrates influence growth and development through events in the gut and direct and indirect effects of different metabolites deriving from carbohydrate assimilation.

Energy content and amino acid digestibility of extruded and dehulled-extruded corn by pigs and its effect on the performance of weaned pigs

“…This supports previous reports that extrusion may improve protein digestibility in feeds through protein denaturation making the protein molecules more susceptible to proteolytic enzymes (Fadel et al, 1988;Hancock, 1992;Muley et al, 2007). Also, it is known that starch is associated with proteins in cereal grains and therefore, through the gelatinization of starch, through extrusion, the proteins may also become more accessible to enzymatic digestion (Knudsen, 2011).…”

The role of added feed enzymes in promoting gut health in swine and poultry

“…Interestingly, in the same study some birds were fed diets supplemented with xylanase instead of AXOS and the scale of the (9,103) and Meng (86) . † Includes lignin.…”

Factors affecting starch utilization in large animal food production system: A review

“…In swine nutrition, dietary starches from different feed grains are however digested and absorbed at different rates and to different extents depending on their physico‐chemical characteristics. The physico‐chemical characteristics can modulate the post‐prandial metabolic response, with possible implications on feed intake, nutrient digestibility, hormone release, metabolism of amino acids, energy expenditure, protection against swine dysentery, nitrogen retention and carcass composition . For instance, slowly digestible starch can decrease net portal glucose and increase net portal VFA flux as compared to feeding pigs rapidly digestible starch .…”