Dietary fibre crude fibre cellulose NSP NDF cellulose

Dietary fibre crude fibre cellulose* NSP NDF cellulose dietary fibre cellulose hemicellulose* hemicellulose lignin pektin β-glucan arabinoxyl an an * = not the total content ADF ADL cellulose lignin

Cellulose • cell wall structure (10 -15 thousand glucose units) • does not soluble in water • higher animals and humans can’t digest • bacteria in the rumen and large intestine produce cellulase enzyme

The structure of starch and cellulose starch cellulose

Hemicelluloses • closely associated with cellulose • can bind water • not homogenous structure (glucose, galactose, mannose, xylose, arabinose polymers) • can metabolise only bacteria

Pectic subtances • the first compound of primary cell walls • the linear chain of galacturonic acid • good water absorbing capacity • soluble in hot water, but animals can not digest • contains considerable gelling properties (jam making)

Lignin • is not a well defined compound • alcohol polymer • high résistance to chemical degradation • binding to cell wall polysaccharides, mostly cellulose • wood products and straw are rich • do not solve in water • from nutritional point of view has a negative effect

Other fibre compounds • -glucan, arabinoxylan (wheat, barley, rye, oats) – anti-nutritive effect – increasing the viscosity of the digesta – decrease the digestibility of nutrients – sticky droppings, Salmonella contamination of eggs • chitin – a linear polymer of glucose amine, containing insects, fungi, and green algae • exudate gums – produces from wounds of plants, contains arabinose, galactose, glucuronic acid

The effect of fibre in the nutrition of ruminants • chewing, rumination, producing saliva, rumen contraction • structural fibre (min. 75% of crude fibre) • only microbes in the digestive tract produce digestive enzymes (cellulase, hemicellulase etc. ) • energy source, precursor of volatile fatty acids • has an influence on the time of rumen fermentation, the transport time of chyme in the intestine

Rumen degradation of dietary carbohydrates hemicellulose pectin starch sucrose lactose CH 3 C=O COOH pyruvate acetate propionate butyrate

The effect of fibre in the nutrition of monogastric animals • bacterial degradation only in the caecum and large intestine (horse, rabbits) • peristaltic movement of the intestine horse > rabbit > pig > poultry 12 -20% 10 -14% 3 -8% 3 -6% • young animals need less • high fibre decrease the digestibility of the other nutrients • increase endogenous losses • chyme transport time decrease • high fibre means less concentrated food • satiety feeling

Symptoms of fibre deficiency • • rumen function disturbances constipation anorexy oesophageal and stomach ulcers

Crude fibre content of some feedstuffs (%) alfalfa corn silage hay (good quality) barley straw 6, 9 12, 9 25, 8 35, 6 barley wheat corn grain full fat soybean extracted soybean meal sugar beet potato pumpkin 4, 9 2, 6 6, 9 13, 5 1, 2 0, 7 0, 8

Fibre requirement of different animal species (%) young pigs (10 -20 kg) 2, 5 older pigs (70 -110 kg) 3, 5 broiler chick (0 -3 hét) 2 -3 broiler chick (5 -6 hét) 3 -4 laying hen 5 horse 12 -16 rebbit 11 -12 milking cow 17 -23

Effect of dietary fibre in the human nutrition • requirement: 30 -40 g/day • consumption: 15 -25 g/day Consequences of fibre deficiency : • large bowel problems, diseases (constipation, diverticuloses, colon or rectal cancer) • metabolic disorders (obesity, diabetes high blood lipid parameters)