Fundamentals of Small Animal Nutrition

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Fundamentals of Small Animal Nutrition

• Carbohydrates
• Dr. Randy Ackman

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Carbohydrates

• Carbohydrates
• Composed of
• Carbon
• Hydrogen
• Oxygen
• 1 carbon 2 H2O
• Primary energy source for animals
• 60-90 dry matter basis of plants

http//www.ccnmtl.columbia.edu/projects/biology/le
cture3/images/carbosrjp22.gif
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Carbohydrates

• Classification of Carbohydrates
• Monosaccharides
• Simple sugars
• Pentoses
• 5 carbons
• Ribose
• Deoxyribose
• Hexoses
• 6 carbons
• Glucose
• Galactose
• Fructose

http//www.cem.msu.edu/cem252/sp97/ch18/ch18s5.GI
F
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Chemical Formulas

• Empirical formula group of chemical symbols
  that shows which elements, and how many of each
  in a compound.
• Structural formula a drawing that represents
  the spatial position of the elements in a
  compound.
• Isomers molecules that have the same empirical
  formula, but different structural formulas

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Carbohydrates

• Monosaccharides
• Glucose
• End product of
• Starch digestion
• Glycogen hydrolysis
• Primary source of energy
• Important for brain
• ATP derived from aerobic cellular respiration
• Fructose
• Found in fruits
• High fructose corn syrup

http//www.uccs.edu/rmelamed/MicroFall2002/Chapte
r202/glucose20fructose.jpg
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Carbohydrates

• Disaccharides
• Sucrose
• Glucose and fructose
• Maltose
• Glucose and glucose
• Intermediate in starch digestion
• Lactose
• Most important disaccharide in animals
• High concentrations in milk

http//dwb.unl.edu/Teacher/NSF/C11/C11Links/www.fo
rdham.edu/Biochem_3521/lect14/dissacharides.GIF
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Aerobic Cellular Respiration
http//fig.cox.miami.edu/Faculty/Dana/krebs.jpg
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Important Reactions in Biochemistry

• Dehydration synthesis the combining of two
  units (monomers) by removing H-OH (H2O)
• The adding of numerous units (monomers) to form
  a longer molecule results in a polymer.

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Important Reactions in Biochemistry

• Hydrolysis reaction breaking down of larger
  polymers to smaller units by the addition of H2O.

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Carbohydrates

• Polysaccharides
• Polymer
• Chains of monosaccharides linked together to form
  complex chains
• Starch
• Cellulose
• Glycogen
• Dietary fiber
• Cellulose
• Chitin

http//bioweb.wku.edu/courses/BIOL115/Wyatt/Bioche
m/Carbos/Carb_poly.gif
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Carbohydrates

• Starch
• Main carbohydrate source in commercial dog foods
• Found in grains
• Corn
• Wheat
• Sorghum
• Barley
• Rice
• Amylase
• Digests starch
• Salivary
• Pancreatic

http//www.uccs.edu/rmelamed/MicroFall2002/Chapte
r202/polysacharides.jpg
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Carbohydrates

• Dogs
• Excess carbohydrates not a problem usually
• Dry food
• 30-60 carbohydrates
• 3.5kcal/g
• Omnivores

• Cats
• Low disaccharidases
• Sucrase
• Lactase
• 5 of pancreatic amylase as dogs
• Lack hepatic glucokinase
• Limits ability to digest large amounts of CHOs
• Maldigestion
• Diarrhea, bloating, gas
• Up to 35 diet
• Carnivores

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Carbohydrates

• Glycogen
• Storage (short term) of carbohydrate in animal
• Liver
• Small amount in puppies/ kittens
• Muscle
• Why?
• Carb loading
• Maintains homeostasis of glucose
• Glycogenesis
• Glycogenolysis
• Gluconeogenesis

http//www.elmhurst.edu/chm/vchembook/images/604g
lycogenesis.gif
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Carbohydrates

• IMPORTANT HYPOGLYCEMIA!!
• Puppies
• Particular small breed
• Periods of anorexia
• Surgery
• Infection
• Stress
• Signs
• Lethargy, ataxia, seizures, coma, death

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Carbohydrates

• Dietary fiber
• Hemicellulose
• Pectin
• Plant gums
• Cellulose
• ß-configuration
• Not broken down by enzymes
• Starch contains a - configuration

http//www.elmhurst.edu/chm/vchembook/images/547c
omparestarchcell.gif
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Carbohydrates

• Dietary fiber
• Intestinal microbes digest some
• Production of short chain fatty acids SCFA
• Acetate
• Proprionate
• Butyrate
• SCFAs
• Transit time in GI tract

http//www.astrographics.com/GalleryPrints/Display
/GP2144.jpg
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Carbohydrates

• SCFAs
• Energy source in ruminants and herbivores
• Increased gut length
• Complex structure
• Not absorbed
• Does not affect total energy
• Significant energy source for
• Enterocytes
• Coloncytes

http//caninehealthnutrition.com/Images/gsdigest6.
JPG
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Carbohydrates

• Fermentability
• Moderately fermentable fiber
• Increased colon weights
• Increased mucosal surface area
• Mucosal hypertrophy
• Increased absorptive capability
• Increased cellular activity
• Increased health

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Carbohydrates

• Dietary Fiber
• Best fiber source
• Moderately fermentable
• Adequate SCFAs produced
• Bulk
• Fermentation rate increases
• GI transit time decreases
• Fecal bulk decreases (volume)
• Rapid ferementers may be used as laxatives
• Slow fermentation
• Increase fecal bulk (volume)
• Retain structure and hold water

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Carbohydrates

• Dietary fiber
• Increase fecal bulk and water in intestinal
  contents
• Shortens transit time in normal or prolonged
  transit time
• Lengthens transit time in dogs with increased
  transit time

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Carbohydrates

• Functions of Carbohydrates
• Energy source
• Glucose CNS especially
• Energy storage
• Glycogen
• Carbon skeletons for non- essential amino acids
• Synthesis
• DNA, RNA, structural components