Changes

[[File:Carbohydrate digestibility.jpg|400px|right]]

[[File:Carbohydrate digestibility.jpg|400px|right|thumb|© Diffomédia/Masure]]

Unlike humans, '''dogs and cats lack salivary amylase''' and enzymatic digestion of [[Carbohydrates Overview - Nutrition|carbohydrate]] begins in the [[Small Intestine - Anatomy & Physiology|small intestine]].<ref name="Morris">Morris JG, ''et al''. (1997) '''Carbohydrate digestion by the domestic cat (''Felis catus). '''Br J Nutr'' 1997;37:365-373.</ref><ref name="Hilton">Hilton J. (2006) '''Carbohydrates in the nutrition of dog.''''' Can Vet J ''1990;46A:359-369.</ref> The sugar alcohols mannitol, sorbitol, and xylitol are found as straight chain carbons instead of hexose (glucose and galactose) or pentose (fructose) carbon ring structures and sugar alcohols are absorbed by diffusion across the intestinal mucosa without hydrolysis.<ref name="NRC">National Research Council (NRC). (2006) '''Carbohydrates and Fiber. In Nutrient Requirements for Dogs and Cats. '''2006 ''Washington, DC: National Academies Press'' p.51-54.</ref> Dietary monosaccharide can be absorbed directly via facilitated diffusion and Na²⁺-dependent glucose transporters, while disaccharide and absorbable polysaccharide carbohydrates must first be broken down by mammalian enzymes into their monosaccharide subunits.<ref name="NRC" /> Disaccharides are hydrolysed by small intestinal enzymes (maltase, sucrase and lactase) while longer chain [[Nutrition Glossary#Polysaccharides|polysaccharides]] (i.e. absorbable starches) must first be hydrolysed by pancreatic α-amylase. Pancreatic α-amylase breaks the α-1,4 glycosidal linkages in starch<ref name="Colonna">Colonna P, ''et al.'' (1992) '''Limiting factors of starch hydrolysis.''''' Eur J Clin Nutr ''1992;46:S17-S32.</ref>. Secretion of pancreatic α-amylase, with lipase, colipase and trypsin, is under the influence of cholecystokinin (CCK), though CCK release itself is stimulated by the presence of free [[Fatty Acids Overview - Nutrition|fatty acids]] and [[Amino Acids Overview - Nutrition|amino acids]], not carbohydrates, in the duodenal lumen.<ref name="Backus">Backus RC, ''et al.'' (1995)''' Elevation of plasma cholecystokinin (CCK) immunoreactivity by fat, protein, and amino acids in the cat, a carnivore. '''''Regul Pept ''1995;57:123-131.</ref>

Unlike humans, '''dogs and cats lack salivary amylase''' and enzymatic digestion of [[Carbohydrates Overview - Nutrition|carbohydrate]] begins in the [[Small Intestine - Anatomy & Physiology|small intestine]].<ref name="Morris">Morris JG, ''et al''. (1997) '''Carbohydrate digestion by the domestic cat (''Felis catus). '''Br J Nutr'' 1997;37:365-373.</ref><ref name="Hilton">Hilton J. (2006) '''Carbohydrates in the nutrition of dog.''''' Can Vet J ''1990;46A:359-369.</ref> The sugar alcohols mannitol, sorbitol, and xylitol are found as straight chain carbons instead of hexose (glucose and galactose) or pentose (fructose) carbon ring structures and sugar alcohols are absorbed by diffusion across the intestinal mucosa without hydrolysis.<ref name="NRC">National Research Council (NRC). (2006) '''Carbohydrates and Fiber. In Nutrient Requirements for Dogs and Cats. '''2006 ''Washington, DC: National Academies Press'' p.51-54.</ref> Dietary monosaccharide can be absorbed directly via facilitated diffusion and Na²⁺-dependent glucose transporters, while disaccharide and absorbable polysaccharide carbohydrates must first be broken down by mammalian enzymes into their monosaccharide subunits.<ref name="NRC" /> Disaccharides are hydrolysed by small intestinal enzymes (maltase, sucrase and lactase) while longer chain [[Nutrition Glossary#Polysaccharides|polysaccharides]] (i.e. absorbable starches) must first be hydrolysed by pancreatic α-amylase. Pancreatic α-amylase breaks the α-1,4 glycosidal linkages in starch<ref name="Colonna">Colonna P, ''et al.'' (1992) '''Limiting factors of starch hydrolysis.''''' Eur J Clin Nutr ''1992;46:S17-S32.</ref>. Secretion of pancreatic α-amylase, with lipase, colipase and trypsin, is under the influence of cholecystokinin (CCK), though CCK release itself is stimulated by the presence of free [[Fatty Acids Overview - Nutrition|fatty acids]] and [[Amino Acids Overview - Nutrition|amino acids]], not carbohydrates, in the duodenal lumen.<ref name="Backus">Backus RC, ''et al.'' (1995)''' Elevation of plasma cholecystokinin (CCK) immunoreactivity by fat, protein, and amino acids in the cat, a carnivore. '''''Regul Pept ''1995;57:123-131.</ref>