Carbohydrates Overview in Animal Nutrition

Comprise 60% to 70% of animal diets and serve as a major energy source.
Energy utilization for microbes supports their metabolism, growth, and protein synthesis.
Animals primarily benefit from the digestible carbohydrates that escape fermentation in the rumen.

Nonstructural Carbohydrates (NSC): Include storage compounds like sugars and starches.
Structural Carbohydrates (SC): Constitute cell walls; include hemicellulose and cellulose.

Pentoses:
- Mainly exist as polymers (pentosans) associated with hemicellulose in cell walls.
- Contribute to energy after microbial fermentation. Ribose plays crucial roles in ATP, DNA, and RNA formation.
Hexoses:
- Glucose: Found in fresh fruits and as a starch digestion product; primary energy source and a constituent of sucrose and lactose.
- Galactose: A sugar unit of lactose, converted to glucose in the liver; not found freely in nature.
- Fructose: A ketose sugar, important in baby pig diets, found in fruits and honey; sweeter than glucose.

Disaccharides include:
- Maltose, isomaltose, sucrose, lactose.
Polysaccharides include:
- Starch: Main energy reserve in seeds, key energy source.
- Glycogen: Energy storage in animals.

Fiber is a combination of lignin and polysaccharides indigestible by digestive tract enzymes.
Typical cell walls comprise 20-40% cellulose, 10-40% hemicellulose, and smaller percentages of lignin and pectin.

Most abundant carbohydrate; a structural component of plant cell walls.
Composed of beta-1,4-linked D-glucose; resistant to hydrolysis by nonruminants but digestible by microorganisms.

Non-starch polysaccharide found between and within cell walls.
Extractable with water, forms gels, and is highly fermentable despite lacking mammalian digestive enzymes.

A non-carbohydrate structural component of plant cell walls, providing support.
Consists of high molecular weight, amorphous polymers derived from phenylpropane.