Carbohydrates and it's classification and nutritional importance in animals

Carbohydrates, classification and it's digestion in ruminants and non ruminants, and abnormal carbohydrates metabolism

1. Carbohydrates

2. Carbohydrates Carbohydrates are organic substances containing carbon, hydrogen and oxygen (hydrates of carbon). Carbohydrates are basic energy source in animal cells. Animal metabolism produces energy in a reverse process to that of photosynthesis in plants.

3. DIGESTION OF CARBOHYDRATE IN RUMINANTS

4. Carbohydrate digestion in ruminants and monogastric animals Ruminants Monogastric animals Major carbohydrates: Starch, Cellulose, hemicellulos. Starch Site of digestion: small intestines Rumen End product of digestion: VFA and some monosaccharides glucose Digest all plant carbohydrates including cellulose Don't digest cellulose Produces more saliva with no carbohydrate digestive enzymes Produces less saliva with carbohydrate digesting enzymes

5. Nutritional importance of carbohydrates Most nutritionally important sugars are pentoses and hexoses. Nutritionally important sugars are of D form. Glucose: Primary carbohydrate used by body for energy production Fructose(fruit sugar):- Ripened fruits and honey Galactose:- mammalian milk Some oligosaccharide are used as substance to enhance the growth of good microbes (Prebiotics) ex.. Fructooligosacharides , mannan oligosaccharides

6. Functions of polysaccharides include Energy storage in plant cells (seed starch in cereal grain) Animal cells (glycogen) Structural support (plant fiber) Starch is the chief carbohydrate source in the diet of monogastric animals. Cellulose is most abundant carbohydrate in nature. No animal enzyme can break it, only microbial cellulase can degrade it. Two major pathways of glucose catabolism are glycolysis and TCA cycle.

7. Non starch polysaccharides Non Starch Polysaccharides (NSPs) are polymeric carbohydrates which differ in composition and structure from starch and possess chemical cross linking among them The NSP is a fraction of carbohydrate in feed and it does not include starch and free sugars. They cannot be digested by animal enzymes but are fermented by hindgut and rumen microbes. Soluble NSPs includes Arabinoxylans, ß-glucans , pectins, mannans, glucomannans. Insoluble NSPs include cellulose , some hemicelluloses.

8. High levels of w ater soluble NSP -in monogastric diet – Viscous digesta -interfere with digestion- Malabsorption. Poultry- wet litter, dirty eggs & diarrhea. Insoluble NSP increases the faecal bulk and promotes peristalsis of intestines, accelerates colonic transit and thus prevents constipation.

9. Function of Carbohydrates Source of energy for muscular activity, heart muscles etc. Carbohydrates are needed for oxidation of fat Synthesis of ribose from glucose. For synthesis of fatty acids For synthesis of non-essential amino acids eg. oxaloacetate → aspartic acid For glycolipids synthesis For ascorbic acid synthesis

10. Abnormal Carbohydrate metabolism Ketosis:- Hypoglycaemia Fatty liver :- Disorder of highly productive dairy cows, Excessive negative energy balance at the onset of lactation Acidosis :- Excess carbohydrate feeding in ruminants Laminitis:- Carbohydrate overload