Classification of Nutrients

Transcription

1 Classification of Nutrients Nutrients; Definition and Classification Nutrients Any chemical compound/substance having specific function in the nutritive support of animal life 20 Elements make 40 nutrient chemicals (including AAs) 1. Water 2. Carbohydrates 3. Fats 4. Proteins 5. Minerals 6. Vitamins 1 2 Functions of Nutrients 1. Basic Functions 1. As a structural material for building and maintaining the body structure. Bone, muscles, skin, organs etc. Maintenance 2. As a source of energy for heat production, work, and/or fat deposition. Keep body warm and to do work Functions of Nutrients 3. For regulating body processes or in the formation of body produced regulators Enzymes, hormones etc. 2. Accessory Functions Milk production Egg production Fetal growth 3 4

2 Functions that nutrient may serve Nutrients As a structural material for body building and maintenance Basic Functions As energy for heat production, work, and fat deposition As or for the formation of body regulators Accessory Functions As a source of nutrient for milk (or egg) production Proteins Yes Yes Certain AA Yes Carbohydrates Fats Only as fat formed enters into make up of cellular growth Only as fat enters into make up of cellular growth Yes Yes Yes Yes Certain fatty acids Minerals Yes No Yes Yes Vitamins No No Yes Yes Yes Water Functions, Sources, Metabolism and Factors Affecting Requirements Water Yes No Yes Yes 5 6 Water The most vital nutrient Makes up 71 73% of the fat free animal body weight Body can lose nearly all fat and over half of its protein and live 10 15% loss of water will result in death (20% of body weight; BW) Water is usually the cheapest nutrient on a cost per unit basis 7 Water.Importance Species Percentage water contents of the animal body Water (contents of GIT not included) Calf, new born 74 Calf, fat 68 Steer, thin 64 Sheep, thin 74 Sheep, fat 40 Horse 60 Hen 69 Human 60 8

3 Water Importance Dairy cows need 4 to 4.5 lit. per lit. of milk produced Dairy cow usually consume 3-4 units of water for each unit of dry feed consumed (57-95 lit. or more daily for high producing cows) A single cow may consume up to 140 lit. of water daily via drinking water and ration Drinking water generally provides 80-90% of water needs Basic functions of water 1. Major Component in body metabolism 2. Major factor in body temperature control 9 10 Properties and functions of water WATER AND BODY METABOLISM Solvent and ionizing power Ideal for dispersal of organic and inorganic molecules Facilitation of cell reactions Surface tension Reduces evaporation for liquid air interfaces Influences pulmonary function Properties and functions of water Water as a transport medium and as a dilutent Facilitates digestion, transportation and excretion of other nutrients and metabolites Intimate involvement in many biochemical reactions Reactant/substrate (e.g., hydrolysis; water is a substrate in the reaction) Product of the reaction (e.g., oxidation) 11 12

4 Properties and functions of water Body water distribution WATER AND BODY TEMP. REGULATION High specific heat, high thermal conductivity, high latent heat of vaporization Absorbs metabolic heat 1g of water takes up 580 Cal when changes from liquid to vapor Helps regulate body temperature Total body water content is inversely related to body fat content Water content of lean body tissues is relatively constant at 70-75% Body water distribution 30-40% of total body water is in extracellular fluid (20-25% of the BW) Blood plasma is 5% of body weight Remainder is interstitial fluid 60-70% of total body water is in intracellular fluid (45% of the BW) Body water turnover: is directly related to body water content Factors affecting body water Genotype Bos taurus vs Bos indicus Age Decreases with age Environmental temperature Feed quality and quantity Physiological state 15 16

5 Sources of body water 1. Drinking free water 2. In or on feed Dry diet vs wet feeds 3. Metabolic water from nutrient oxidation Sources of body water 4. Water liberated from metabolic reactions such as condensation of AA to peptides 5. Preformed water associated with body tissue catabolized during a period of negative energy balance Metabolic water Metabolic water and oxygen Glucose + 6 O 2 6 CO H 2 0 Alanine + 3 O CO 2 + CO(NH 2 ) H 2 0 Palmitic acid + 23O 2 16 CO H

6 Water losses Urine Ambient temperature Digestible dry matter intake N intake, metabolism and excretion Feces Genotype Sheep (50-60% water); Cattle (80% water) Water intake Dry matter intake Fiber content of feed Water losses Evaporation Ambient temperature Physiological state Lactation (milk contain 87% water) Pregnancy/dry Water metabolism (g/d) of sheep Water balance of Holstein cows 23 24

7 Water requirements Affected by factors that influence water loss Dry matter intake (DMI) Recommendations for water intake are often expressed in terms of DMI Physiological state Ambient temperature Genotype Salt contents of diet and water Water requirements Effect of water content of feeds on drinking water consumed % water in diet (L) Drinking water Feed water Total water a 25 a Lower because of lower DM intake on the high moisture diets Woodford et al. (1985) 26 Water requirements Water requirements (Average) Effect of additional salt in the diet on water intake Diets Intake Basal Basal + 2% NaCl Dry matter (kg/day) Basal + 2% Na 2 CO Water (L/day)

8 Water requirements (Average) kg water/kg dry matter intake Environmental temperature ( o C) < > 20 Calves (upto 6 weeks) Cattle (Growing/Adult, Pregnant/ Nonpregnant) Dairy cows (lactating); 600 kg animal Dairy cows (lactating); 350 kg animal Lambs (upto 4 weeks) Sheep (Growing/Adult, Pregnant/ Nonpregnant) Ewes: Mid pregnancy, twin bearing Ewes: Late pregnancy, twin bearing Ewes (lactating); First month Ewes (lactating); 2 nd third month Water absorption In Ruminants: Rumen and omasum In all species: Ileum, jejunum, cecum and large gut Difference in osmotic pressure helps in absorption Rapid absorption if fluid are absorbed without food Polysaccharides (pectin gel formation) and fiber in GIT reduces absorption 30 Water turnover Rate at which body water is excreted and replaced in the tissues Higher turnover rates in non ruminants due to less water in the GIT. Low turnover rates in species (camel) that tolerate greater water restrictions. Salt intake and climatic factors affects water turnover rates. Water quality Salinity (total dissolved solids, mg/liter) Slightly saline 1,000-3,000 Moderately saline 3,000-10,000 Very saline 10,000-35,000 Brine (ocean) >35,000 3,000-5,000 problem for poultry 5,000-7,000 fine after adaptation for dairy and beef cattle, sheep, swine and horses Tolerance: Sheep > cattle > pigs 31 32

9 Minerals in water Most abundant salts in saline water Na with Ca and Mg Carbonates, bicarbonates, chlorides and sulfates Sulfates are more harmful than chlorides Minerals present include P, Ca, Mg, Na, K, Cl, S, Cu, Fe, Mn, Zn, Se, I and Co Types of Water Quality Problems Low Intake and Milk Production Perceived or measured? Usually aesthetic pollutants Especially common in mining areas Health Effects Often more difficult to determine cause Many potential pollutants Water: References for further study 1. Pond, W.G., D.C. Church, K.R. Pond and P.A. Schoknecht Basic Animal Nutrition and Feeding. 5 th Edition. Page No Wiley International Edition, USA. 2. Sarwar, M. and Zia ul Hasan, Nutrient Metabolism in Ruminants. University of Agriculture Press, Faisalabad. 35