ANIMAL NUTRITION & FEEDING - I

Animal Nutrition and Feeding

Part 1 - Overview

  • Study of fundamental components of animal nutrition which includes carbohydrates, fats, and proteins.

Definitions

  • Animal Nutrition: The science dealing with the dietary requirements of animals. Food is defined as material that, after ingestion by animals, is capable of being digested, absorbed, and utilized.

  • Food Composition in Farm Animals: Predominantly consists of plants and plant products, with minimal use of animal-origin foods such as fishmeal and milk.

Photosynthesis and Energy Storage

  • Plants can synthesize complex materials using simple substances:

    • Carbon dioxide from the air

    • Water and inorganic elements from the soil

  • Photosynthesis: The process in which energy from sunlight is captured and utilized in the synthesis of these materials, leading to the storage of energy in the form of chemical energy within plants. This stored energy is essential for animals for life maintenance and tissue synthesis.

Chemical Composition of Foods

  • Plants and animals share similar chemical substances that can be classified based on composition, properties, and functions. Main classes include:

    • Organic Components:

    • Carbohydrates

    • Lipids

    • Proteins

    • Nucleic acids

    • Organic acids

    • Vitamins

    • Inorganic Components: Minerals

Water in Animal Nutrition

  • Water (H2O)

    • Acts as a solvent for nutrient transport and waste excretion.

    • Essential for chemical reactions involving enzymes and hydrolysis.

    • Sources of water for animals:

    1. Drinking Water

    2. Water in Food

    3. Metabolic Water: Produced during metabolism via the oxidation of hydrogen-containing organic nutrients.

Carbohydrates

General Characteristics

  • Carbohydrates are neutral chemical compounds made of carbon, hydrogen, and oxygen.

  • Empirical formula: (CH2O)n, where n ≥ 3.

  • Some carbohydrates may contain phosphorus, nitrogen, or sulfur; examples include deoxyribose (C5H10O4).

Classification of Carbohydrates

  • Sugar: Carbohydrates with fewer than ten monosaccharide residues.

  • Oligosaccharides: Include all sugars other than monosaccharides. Monosaccharides can bond, losing one molecule of water at each connection, forming chains:

    • Monosaccharides (2 to many units):

    • Trioses: C3H6O3

    • Tetroses: C4H8O4

    • Pentoses: C5H10O5

    • Hexoses: C6H12O6

    • Heptoses: C7H14O7

Monosaccharides Examples

  • Trioses: Glyceraldehyde, Dihydroxyacetone

  • Tetroses: Erythrose, Arabinose, Xylose, Xylulose

  • Pentoses: Ribose, Ribulose

  • Hexoses: Glucose, Galactose, Mannose, Fructose

Key Monosaccharides

Glucose

  • Also known as grape sugar or dextrose.

  • Primary energy source, found in free state in fruits, honey, and animal fluids.

  • Chemical formula: C6H12O6.

  • Properties: White crystalline solid, soluble in water, key component of oligosaccharides and polysaccharides.

Fructose

  • Known as fruit sugar or laevulose.

  • Found in fruits, green leaves, and honey; part of sucrose and fructans.

  • Sweeter than sucrose, exists as a white crystalline solid.

Mannose

  • Exists mainly in polymeric form as mannan.

  • Found widely in yeasts, molds, and bacteria.

  • Used in medicine to prevent UTIs by inhibiting bacteria from adhering to bladder walls.

Galactose

  • Occurs primarily in dairy as part of lactose and during fermentation as a breakdown product.

  • Less commonly found than other sugars, involved in plant anthocyanin pigments and galactolipids.

Disaccharides

  • Formed by the linkage of two monosaccharides through a glycosidic bond.

  • Nutritionally significant disaccharides include:

    • Sucrose (C12H22O11): Table sugar from glucose and fructose.

    • Maltose: Composed of two glucose units, produced during starch hydrolysis.

    • Lactose: Found in milk, composed of glucose and galactose.

    • Cellobiose: Basic unit of cellulose not found free in nature.

Sucrose

  • Most common disaccharide, widely spread in plants.

  • Hydrolyzed by enzyme sucrase.

  • Found abundantly in sugar cane and beet.

Maltose

  • Known as malt sugar, produced during starches hydrolysis, including during barley germination for beer production.

  • Used in baking and candy-making.

Lactose

  • Milk sugar; less soluble and less sweet than sucrose but necessary for young mammals.

Cellobiose

  • Not naturally free, key component of cellulose, split by microbial enzymes but not by mammalian ones.

Polysaccharides

  • Complex carbohydrates with high molecular weight formed from long chains of monosaccharides.

  • Most abundant carbohydrates, acting mainly as energy storage (starch, glycogen) or structural components (cellulose, chitin).

  • Generally insoluble in water and non-sweet.

Homoglycans Examples

  1. Starch: Reserve carbohydrate in plants; insoluble in cold water but gelatinizes when heated.

  2. Glycogen: Highly branched structure in animals used for quick glucose mobilization during stress.

  3. Cellulose: Found in plant cell walls, significant in dietary fiber yet indigestible by many mammals.

Callose

  • Composed of β-(1,3)-linked glucose; important in responses to plant wounding.

Chitin

  • Polysaccharide of acetyl-D-glucosamine prevalent in fungal cell walls and crustacean exoskeletons.

Lignin

  • Not a carbohydrate but important structural polymer in plant cell walls, affecting digestibility.

Lipids

Introduction to Lipids

  • Group of substances including fats, oils, and others, characterized by insolubility in water but solubility in organic solvents.

  • Functions:

    • Energy storage and insulation

    • Cell membrane formation and signaling functions

Classification of Lipids

  • Non-glycerol-based: Includes sphingolipids, waxes, steroids, etc.

  • Glycerol-based: Include fats, oils, and phospholipids.

Fats and Oils

  • Saturated fatty acids: Solid at room temperature, found in animal fats and some tropical oils; health implications include increased heart disease risk.

  • Unsaturated fatty acids: Healthy fats found in plant oils and fatty fish; beneficial for heart health.

Glycolipids

  • Composed of carbohydrate and lipid; important for cell membrane stability and cell-cell recognition.

Phospholipids

  • Major component of biological membranes, abundant in tissues like heart and brain.

Waxes

  • Protective coatings in plants and animals, preventing water loss through transpiration and providing waterproofing.

Proteins

Introduction to Proteins

  • Complex organic compounds containing carbon, hydrogen, oxygen, and nitrogen (often sulfur).

  • Key functional molecules in all biological activities.

Amino Acids

  • Proteins are hydrolyzed into amino acids; over 200 amino acids exist, but only 20 are commonly found in proteins.

Essential Amino Acids

  1. Arginine

  2. Histidine

  3. Isoleucine

  4. Leucine

  5. Lysine

  6. Methionine

  7. Phenylalanine

  8. Threonine

  9. Tryptophan

  10. Valine

Non-Essential Amino Acids

  • Synthesized by the body and thus may not need supplementation:

  1. Alanine

  2. Aspartic Acid

  3. Citrulline

  4. Cystine

  5. Glutamic Acid

  6. Glycine

  7. Hydroxyproline

  8. Proline

  9. Serine

  10. Tyrosine

Conditional Amino Acids

  • Taurine: Considered conditionally essential for functions like vision, digestion, and muscle function, particularly in cats.

Note: This summary is expansive but not exhaustive; explore each category further for in-depth understanding related to animal nutrition.