Unit 2 Animal Nutrition

Unit 2 

Minerals, Vitamins and Feed additive 

1. Macrominerals and their deficiency system
2. Microminerals and their deficiency system
3. Fat Soluble vitamin and their role
4. Water Soluble vitamin and their role
5. Feed Additives in Livestock Nutrition   

Classification of Minerals: Two type

Major (Macro) Minerals

• Calcium (Ca)
• Phosphorus (P)
• Sodium (Na)
• Chlorine (Cl)
• Potassium (K)
• Magnesium (Mg)
• Sulphur (S)

Minor (micro) Minerals

• Zinc (Zn)
• Copper (Cu)
• Cobalt (Co)
• Iron (Fe)
• Iodine (I)
• Manganese (Mn)
• Selenium (Se)
• Molybdenum (Mo)

Newer Trace Minerals

• Chromium (Cr)
• Fluorine (F)
• Nickel (Ni)
• Arsenic (Ar)

Minerals as Enzyme Components

Mineral	Enzyme	Function
Iron	Cytochromes	Electron transport and energy production
Copper	Cytochrome oxidase, Ceruloplasmin	Electron transport, iron metabolism
Zinc	Carbonic anhydrase, Carboxypeptidase	CO2 transport, protein digestion
Manganese	Pyruvate carboxylase	Gluconeogenesis
Molybdenum	Xanthine oxidase (uric acid)	Purine metabolism
Selenium	Glutathione peroxidase	Antioxidant defence

Key Points

• Calcium and Phosphorus: Vital for bone structure and metabolic processes.
• Sodium, Potassium, and Chlorine: Crucial for maintaining fluid balance and nerve function.
• Zinc, Copper, and Iron: Essential for enzyme function and metabolic processes.
• Selenium and Vitamin E: Work together as antioxidants to protect cells from oxidative damage.

1. Macrominerals and their deficiency system

1.1 Calcium (Ca)

Importance and Functions of Calcium

Approximately 99% of the calcium is found in bones and teeth, where it provides structural integrity. The remaining 1% is involved in vital metabolic functions.

Structural Role: Bones and Teeth-Provides strength and structure.

Metabolic Functions:

             Blood Coagulation: Essential for the clotting process.

Nerve Impulse Transmission: Facilitates the transmission of nerve impulses.

Muscle Contraction: Crucial for muscle function.

Blood Calcium Levels:

Normal Blood Concentration: 9-11 mg/dl.

Layers (Egg-Laying Birds): Higher concentration, around 30-40 mg/dl.

Hormonal Regulation:

Parathormone (PTH): Increases blood calcium levels by mobilizing calcium from bones and enhancing the activation of vitamin D (1,25 di-hydroxy cholecalciferol) in the kidneys.

Calcitonin: Decreases blood calcium levels by inhibiting bone resorption.

Deficiency Symptoms

1. Young Animals:

Rickets-weak and deformed bones due to inadequate mineralization.

2. Adult Animals:

Osteomalacia-Softening of the bones caused by defective bone mineralization.

Milk Fever (Parturient Paresis)- In lactating animals characterized by low blood calcium levels, leading to muscle weakness and paralysis.

1.2 Phosphorus (P) 

It is a component of phosphoproteins, nucleic acids (nucleotides), and phospholipids, which are essential for various physiological functions.

Key Functions

Structural Role:

Phosphoproteins, Nucleic Acids, and Phospholipids-Integral components of cell membranes and genetic material.

Metabolic Functions:

Energy Metabolism-Vital for the formation of ATP (adenosine triphosphate), the primary energy carrier in cells.

Form in Feed:

Phytate/Phytic Acid-The primary storage form of phosphorus in cereal grains, which is less available to non-ruminant animals.

Environmental Impact:

High Levels of Phosphorus-Can contribute to environmental pollution by promoting the growth of algae in water bodies.

Health Issues:

High Phosphorus Intake-In combination with magnesium, can lead to urolithiasis (urinary stones).

Blood Concentration:Normal Levels-4-8 mg/dl.

Deficiency Symptoms

1. Pica (Depraved Appetite/Allotriophagy): 

Abnormal cravings and eating non-food items such as wood, soil, and bones.

2. Post-Parturient Hemoglobinuria (PPH): 

A condition in cows characterized by the breakdown of red blood cells after calving, leading to hemoglobinuria (presence of hemoglobin in urine).

3. Ca:P Ratio: 

The optimal calcium to phosphorus ratio is 2:1. An imbalance can lead to conditions such as “Big Head Disease” in horses, where excessive phosphorus intake relative to calcium causes bone deformities.

1.3 Potassium (K)

Chief Intracellular Cation: Potassium is the primary cation inside cells, playing a crucial role in maintaining cellular function.

Functions:

Nerve and Muscle Activity: Essential for normal nerve impulse transmission and muscle contraction.

Enzyme Activation: Activates various enzymes involved in carbohydrate and protein metabolism.

Sources:

Natural Conditions: Grass and green fodder are rich sources of potassium.

Deficiency Symptoms

Synthetic Milk: Potassium deficiency can occur in animals fed synthetic milk, leading to reduced nerve and muscle activity, and in severe cases, paralysis.

1.4 Sodium (Na)

Chief Extracellular Cation: Sodium is the primary cation outside cells, crucial for maintaining fluid balance and nerve function.

Functions:

Water Intake Increases water intake, which is particularly important during heat stress.

Acid-Base Balance: Helps maintain acid-base balance in the body.

Sources:

Common Salt (NaCl): The primary source of sodium in animal diets.

Deficiency Symptoms

• General: Slow growth, keratinization of corneal epithelium, impotency in males, delayed sexual maturity, and impaired estrus.
• Poultry: Feather picking and cannibalism.
• Salt Poisoning: Common in pigs and poultry when excessive salt is consumed.

1.5 Chlorine (Cl)

Importance and Functions

Functions:

Acid-Base Balance: Helps maintain the acid-base balance in body fluids.

Electrolyte Balance: Works with sodium to regulate osmotic pressure and fluid balance.

Sources

Common Salt (NaCl): The primary source of chlorine in animal diets.

Deficiency Symptoms

• General: Deficiency of chlorine can lead to an abnormal increase in the alkali reserve, resulting in alkalosis.
• Poultry: Deficiency can lead to feather picking and cannibalism.

 1.6 Sulphur (S)

• Amino Acids: Integral component of sulphur-containing amino acids such as cystine, cysteine, and methionine.
• Vitamins: Essential for the synthesis of vitamins like biotin and thiamin.
• Hormones: Part of important hormones like insulin and oxytocin.
• Wool: Rich in cysteine, wool contains about 4% sulphur. The nitrogen to sulphur (N:S) ratio in wool is typically 5:1.
• NPN Supplementation: For non-protein nitrogen supplementation in ruminants, the N:S ratio should be 10:1 (or up to 15:1).

Deficiency Symptoms

• Reduced Feed Intake: Lowered appetite and feed intake.
• Poor Wool Quality: Reduced wool growth and quality due to insufficient sulphur for cystine synthesis.

1.7 Magnesium (Mg)

• Enzyme Activation: Acts as a cofactor for enzymes such as pyruvate carboxylase and pyruvate oxidase.
• Energy Metabolism: Essential for the tricarboxylic acid (TCA) cycle, which is crucial for carbohydrate and lipid metabolism.
• ATP Synthesis: Necessary for the production and utilisation of ATP.
• Normal Blood Levels: 2-4 mg/dl.

Deficiency Symptoms

• Hypomagnesemic Tetany: Also known as grass tetany or lactation tetany, characterised by muscle spasms, convulsions, and potentially death due to respiratory failure.
• Lactation Tetany: Occurs in lactating animals.
• Grass Staggers: A condition in grazing animals, particularly ruminants, due to low magnesium levels in lush, fast-growing pastures.

2. Microminerals and their deficiency system

2.1 Iron (Fe)

• Transport: Iron is transported in the body by transferrin.
• Storage: Stored in the form of ferritin and hemosiderin.
• Enzyme Component: Integral part of various enzymes and proteins involved in oxygen transport and metabolism.

Deficiency Symptoms

• Piglet Anaemia: Known as “thumps,” characterised by laboured breathing due to iron deficiency in young pigs.
• Iron Absorption: Governed by the mucosal block theory, where ferritin saturation in the intestinal mucosa regulates iron absorption.

2.2 Copper (Cu)

• Essential for normal pigmentation of hair, fur, and wool
• Component of turacin, a pigment found in feathers
• Involved in various enzyme systems and oxidation-reduction reactions

Deficiency Symptoms:

1. Lambs: Muscular incoordination leading to sway back condition (enzootic ataxia)
2. Wool: Loss of crimp, resulting in stringy or steely wool due to disruption of disulfide linkages between cysteine molecules
3. Falling disease: Degeneration of heart muscle (myocardium)
4. Microcytic anaemia in pigs, poultry, and calves

 2.3 Cobalt (Co)

• Essential component of cyanocobalamin (vitamin B12)
• Required by rumen microbes for the synthesis of vitamin B12

Deficiency:

• “Pining” condition in ruminants, characterised by:Loss of appetite
  • Loss of appetite
  • Wasting
  • Anaemia
  • Reduced growth and milk production

2.4  Iodine (I)

• Essential component of thyroid hormones (thyroxine and triiodothyronine)
• Increases basal metabolic rate, accelerating growth

Deficiency:

• Goiter (enlarged thyroid gland)
• Reduced growth rate
• Reproductive problems
• Hairless, weak, or stillborn offspring

Note on Goitrogenic Compounds:

• Found in Brassica genus plants (e.g., cabbage)
• Inhibit iodination of tyrosine, interfering with thyroid hormone synthesis

2.5 Manganese (Mn)

• Activates glycosyl transferases, important for bone formation
• Component of various enzyme systems

Deficiency Symptoms:

1. Poultry:

• Perosis (slipped tendon) – malformation of leg bones Reduced hatchability and eggshell thickness
• Head retraction in chicks

2. Other animals: 

• Impaired growth
• Skeletal abnormalities
• Reproductive problems

2.6 Zinc (Zn)

• Component of numerous enzymes:Carbonic anhydrase
• Pancreatic carboxypeptidase
• Lactate dehydrogenase
• Alcohol dehydrogenase
• Alkaline phosphatase
• Thymidine kinase

Deficiency Symptoms:

1. Skin disorders:

Parakeratosis in pigs (thickening and hardening of skin) Bone abnormalities:’Swollen hock syndrome’ in poultry

2. Bone abnormalities:’Swollen hock syndrome’ in poultry

2.7  Molybdenum (Mo)

• Known for its interaction with copper (Cu)
• Acts as an antagonist to Cu, Zn, and sulphur (S)

Toxicity/Deficiency:

• Teartness or peat scour: Can be caused by either Mo toxicity or acute Cu deficiency

2.8 Selenium (Se)

• Considered one of the most toxic minerals when in excess
• Component of glutathione peroxidase enzyme
• Works synergistically with Vitamin E as an antioxidant

Toxicity Symptoms:

1. Alkali disease
2. Blind staggers
3. Degnala disease
4. Hoof deformity

2.9 Fluorine (F):Bureau of Indian Standards (BIS) recommends that F concentration in mineral mixtures should not exceed 0.06%.

Functions:Prevention of dental caries

2.10 Chromium (Cr)

• Acts as a glucose tolerance factor
• Functions similar to insulin-like growth factor (IGF-1)
• Carcass modifying effects:Enhances nitrogen (N) retention
• Helps reduce stress and metabolic disorders

2.11 Nickel (Ni)

• Important for urease activity in the rumen

3. Fat Soluble vitamin and their role

1. Vitamin A
2. Vitamin D
3. Vitamin E
4. Vitamin K

Vitamin A (Retinol)

Vitamin A, also known as retinol. It is derived from carotenoids, such as carotenes and xanthophylls, which are precursors of vitamin A.

Sources

• Carotenoids: Found in plant-based foods, including carotenes (e.g., beta-carotene) and xanthophylls.
• Animal-Based Sources: Liver, fish oils, egg yolk, and dairy products.

Conversion in the Body

• Intestinal Mucosa: Carotenoids are converted into retinol in the intestinal mucosa.
• 1 Molecule of Beta-Carotene: Yields 2 molecules of Vitamin A (Retinol).

Functions

1. Anti-Infective Vitamin: Enhances immune function and helps in the maintenance of epithelial tissues.
2. Vision: Essential for the synthesis of rhodopsin, a pigment in the retina that is necessary for night vision.

3. Reproduction: Supports normal reproduction and embryonic development.
4. Growth and Development: Important for bone growth and development.
5. Skin Health: Maintains the integrity of skin and mucous membranes.

Deficiency Symptoms

1. Night Blindness: Impaired synthesis of rhodopsin leads to difficulty seeing in low light conditions.
2. Xerophthalmia: Dryness of the conjunctiva and cornea, which can lead to blindness.
3. Infertility: Reproductive issues due to impaired development and function of reproductive organs.
4. Nutritional Roup in Poultry: Respiratory infection characterised by nasal discharge, swollen eyes, and reduced egg production.
5. Bitot’s Spots: Foamy patches on the conjunctiva, indicative of severe vitamin A deficiency.

Vitamin D

Types of Vitamin D

1. Vitamin D2 (Ergocalciferol)Source
2. Vitamin D3 (Cholecalciferol)Source

• Hormone-Like Activity: Vitamin D acts like a hormone in the body, regulating calcium and phosphorus metabolism.
• Antirachitic Activity: Prevents rickets, a disease characterised by softening and weakening of bones in young animals.

Deficiency Symptoms

1. Young Animals:Rickets-Characterised by weak and deformed bones due to inadequate mineralization.
2. Adult Animals:Osteomalacia-Softening of the bones caused by defective bone mineralization.

Sources

• Vitamin D2: Found in plants, particularly in fungi and yeast.
• Vitamin D3: Found in animal products such as fish liver oils, egg yolk, and synthesised in the skin upon exposure to sunlight.

Vitamin K

1. Synthesis of Prothrombin: Vitamin K is essential for the synthesis of prothrombin in the liver, a protein and clotting factor that is crucial for blood coagulation.
2. Blood Clotting: It plays a vital role in the blood clotting process by activating clotting factors that help in the conversion of prothrombin to thrombin.
3. Bone Health: Vitamin K is also involved in the regulation of calcium in bones and other tissues.

Deficiency Symptoms

1. Hemorrhagic Conditions: Deficiency in vitamin K can lead to bleeding disorders due to impaired blood clotting. This can manifest as excessive bleeding from wounds, bruising, and internal bleeding.
2. Sweet Clover Poisoning: In cattle, sweet clover poisoning occurs when the plant becomes mouldy and produces dicoumarol, a compound that antagonises vitamin K. This leads to a decrease in prothrombin levels, resulting in hemorrhagic disease.

Sources

• Green Leafy Vegetables: Such as spinach, kale, and broccoli.
• Animal Products: Liver, egg yolk, and fish.
• Synthesised by Gut Bacteria: In the intestines of animals.

Types of Vitamin K

1. Vitamin K1 (Phylloquinone): Found in green plants.
2. Vitamin K2 (Menaquinone): Produced by bacteria in the intestines.
3. Vitamin K3 (Menadione): A synthetic form of vitamin K.

Vitamin E (Tocopherols)

• Antioxidant: Vitamin E acts as a powerful antioxidant, protecting cell membranes from oxidative damage. It works in association with the selenium-containing enzyme glutathione peroxidase.
• Free Radical Scavenging: Vitamin E is the first line of defence against free radicals, neutralising them before they can cause harm.
• Glutathione Peroxidase: This enzyme destroys any remaining peroxides, preventing further oxidative damage.

Deficiency Symptoms

1. Calves:

Nutritional Myopathy: Also known as muscular dystrophy or white muscle disease, characterised by muscle degeneration and weakness.

Fatal Syncope: Sudden death due to heart failure.

2. Lambs:

Stiff Lamb Disease:Muscle stiffness and weakness due to nutritional myopathy.

3. Pigs:

Mulberry Heart Disease: sudden death due to heart muscle degeneration.

Fatal Syncope: Similar to calves, sudden death due to heart failure.

4. Chicks:

Encephalomalacia: Also known as “crazy chick disease,” characterised by neurological symptoms such as incoordination and convulsions.

Exudative Diathesis: Edema and haemorrhages due to increased capillary permeability.

5. Cats:

Yellow Fat Disease:Also known as steatitis, characterised by inflammation of fatty tissues.

Sources

• Green Fodders: Rich in vitamin E.
• Cereal Grains: Good sources of tocopherols.
• Vegetable Oils: High in vitamin E.
• Nuts and Oil Seeds: Rich in tocopherols.

4. Water soluble vitamin and their role

1. Vitamin B Complex 
   1. Thiamin (Vitamin B1)
   2. Riboflavin (Vitamin B2)
   3. Niacin (Vitamin B3)
   4. Pyridoxine (Vitamin B6)
   5. Pantothenic Acid (Vitamin B5)
   6. Folic Acid
   7. Cyanocobalamin (Vitamin B12)
   8. Biotin (Vitamin B7)
   9. Choline
   10. P-Amino Benzoic Acid
   11. Inositol  
2. Vitamin C (Ascorbic Acid)

Vitamin C (Ascorbic Acid)

Sources

• Primary Sources: Citrus fruits and green leafy vegetables are rich sources of vitamin C.
• Synthesis: Most animals can synthesise vitamin C in their bodies from glucose using the enzyme gluconolactone oxidase. However, humans, guinea pigs, and some other species lack this enzyme and must obtain vitamin C from their diet.

Functions

1. Antioxidant: powerful antioxidant, protecting cells from oxidative damage 
2. Collagen Synthesis: Protein that helps maintain the integrity of skin, blood vessels, bones, and connective tissues.
3. Intercellular Cement Substance: Plays a crucial role in the formation of intercellular cement substances, which are important for the maintenance of capillaries, teeth, and bone.
4. Immune Function: Enhances the immune response and helps in the absorption of iron from plant-based foods.

Deficiency Symptoms

1. Scurvy: A disease caused by severe vitamin C deficiency, characterised by symptoms such as:

• Anaemia Dry, rough skin covered with reddish spots
• Weakness and fatigue
• Swollen and bleeding gums
• Loosening of teeth
• Joint pain and swelling

2. Poor Wound Healing: Due to impaired collagen synthesis, wounds may heal slowly.
3. Increased Susceptibility to Infections: Weakened immune response can lead to a higher risk of infections.

Thiamine (Vitamin B1)

• Energy/Carbohydrate Metabolism: Thiamine is essential for the oxidative decarboxylation of pyruvate to acetyl-CoA and of α-ketoglutarate to succinyl-CoA in the tricarboxylic acid (TCA) cycle. These reactions are crucial for energy production from carbohydrates.

Sources

• Natural Sources: Yeast, bran, rice polish, egg yolk, liver, pork.
• Antithiamine Factors:

Thiaminase: Found in raw fish and bracken fern, this enzyme breaks down thiamine, leading to deficiency.

Deficiency Symptoms

1. Accumulation of Pyruvic Acid: Without sufficient thiamine, pyruvate cannot be converted to acetyl-CoA, leading to an accumulation of pyruvic acid, which is then converted to lactic acid. This results in muscular weakness.
2. Excess Polished Rice Consumption: Diets high in polished rice, which is low in thiamine, can lead to deficiency.
3. Polyneuritis: Inflammation of multiple nerves leading to paralysis.

Chastek Paralysis: A specific type of paralysis seen in animals, particularly in those consuming raw fish containing thiaminase.

Riboflavin (Vitamin B2)

• Component of flavoproteins, flavin mononucleotide (FMN), and flavin adenine dinucleotide (FAD)
• Involved in protein and carbohydrate metabolism
• Used by cells to transport hydrogen in metabolic pathways

Sources:

• Synthesised by yeast, bacteria and fungi
• Rich sources include liver, yeast, milk, eggs, and green leafy vegetables

Deficiency Symptoms:

1. Curled Toe Paralysis

• Occurs in poultry, especially chicks 
• Caused by peripheral nerve degeneration
• Characterised by curling of the toes inward, making it difficult for birds to walk

2. Clubbed Down Syndrome/Condition

• Feathers continue to grow within the follicle, leading to curled feathers 
• Affects the appearance and health of the bird’s plumage

• Degeneration of myelin sheath in nerves
• Loss of integrity of epithelial tissues
• In swine: stiff legs, nerve degeneration, corneal opacity, cataracts

Importance:

• Essential for proper nervous system function
• Critical for energy metabolism in cells
• Necessary for normal growth and development
• Important for maintaining healthy skin, eyes, and mucous membranes

Niacin (Vitamin B3)/ Nicotinamide

 Niacin can be synthesised in the body from the amino acid tryptophan.

• Part of Enzyme Systems: A component of the coenzymes NAD (Nicotinamide Adenine Dinucleotide) and NADP (Nicotinamide Adenine Dinucleotide Phosphate), which are crucial for hydrogen transfer in metabolic reactions.
• Energy Metabolism: Involved in the metabolism of carbohydrates, proteins, and fats.

Deficiency Symptoms

• Dermatitis: Inflammation of the skin.
• Specific to Pigs and Poultry:
• Maize-Rich Diets: Maize is low in tryptophan, leading to niacin deficiency in pigs and poultry.
• Pigs: Symptoms include poor growth and skin lesions.
• Poultry: Symptoms include poor feathering and dermatitis.

Vitamin B6 (Pyridoxine)

• Functions: Protein and Amino Acid Metabolism: Acts as a coenzyme in the metabolism of amino acids and proteins.
• Deficiency Symptoms: Convulsions, anaemia, slow growth, and hatchability issues in poultry.

Pantothenic Acid

Functions: Component of Coenzyme A: Essential for acyl transfer and fatty acid metabolism.

Deficiency Symptoms

• Pigs: Goose-stepping gait, characterised by a peculiar high-stepping walk.
• General: Poor growth and skin lesions.

Biotin (Vitamin B7)

Functions: Carboxylation Reactions: Acts as a coenzyme for carboxylase enzymes involved in fatty acid synthesis and gluconeogenesis.

Deficiency Symptoms

• Raw Eggs: Contain avidin, which binds biotin and leads to deficiency.
• Poultry: Fatty liver and kidney syndrome (FLKS), characterised by fat accumulation in the liver and kidneys.
• General: Dermatitis, poor growth, and cracked feet.

Choline

1. Methyl Donor: Choline acts as a methyl donor in transmethylation reactions, which are crucial for fat mobilisation.
2. Transition Animals: Helps prevent metabolic diseases such as ketosis in transition animals (e.g., dairy cows around calving).
3. Poultry Chicks: Prevents perosis (slipped tendon), a condition also influenced by manganese (Mn).

Deficiency Symptoms

• Perosis in Poultry: Characterised by slipped tendon, where the tendon slips from its normal position, leading to leg deformities.

Vitamin B12 (Cyanocobalamin)

1. Synthesis: Vitamin B12 is synthesised exclusively by microorganisms.
2. Mineral Requirement: Requires cobalt (Co) for synthesis.
3. Absorption: Absorbed in the gut when bound to a glycoprotein called intrinsic factor, which is produced in the stomach.

Sources

• Microbial Synthesis: Synthesised by microorganisms in the gut.
• Animal Products: Found in liver, kidney, and other animal products.
• Not Present in Plants: Vitamin B12 is not found in plant-based foods.

Deficiency Symptoms

• Pernicious Anaemia: A type of anaemia characterised by the inability to absorb vitamin B12 due to the lack of intrinsic factor. Symptoms include weakness, fatigue, and neurological issues.

Perosis in Poultry

• Caused By: Deficiency in manganese (Mn), biotin, choline, and folic acid.

5. Feed Additives in Livestock Nutrition   

Supplement: 

• Feedstuffs that are used to improve the value of basal feeds.
• They have their own nutritive value.
• Used in large quantities (protein supplements) or in small quantities (trace minerals).

Feed additive: 

Non-nutritive product added to a basic feed in small quantities that affects utilisation of the feed or productive performance of the animal.

Advantages:

• Increase feed quality and feed palatability

• Improve animal performance

• Improve the final product

• Economise the cost of animal protein

Disadvantages:

• May leave their residues

• May favour the proliferation of antibiotic resistant microorganisms

Types of feed additives:

• Additives that promotes growth and production: antibiotic, probiotic, prebiotics

• Additives that alter metabolism: Hormone (estrogens, androgens, progesterone, GH, thyroxine, glucocorticoids)

• Additives that enhance feed intake: antioxidants, flavouring agents

• Additives that enhance the colour: food colour, pigments

• Additives that facilitate digestion and absorption: grits, enzymes

•Additives that affect the health status of livestock: antifungals, Anticoccidials/coccidiostat, acidifiers

Antibiotics:

• bacteriostatic or bactericidal properties.

• Prevent subclinical infections

• Example: penicillin, oxy-tetracycline, chlortetracycline, bacitracin, streptomycin, neomycin, erythromycin       

Mechanism of action of antibiotics includes:

• Nutrient sparing effect by increasing growth of vitamin and protein synthesising microorganism

• Reduces the thickness of the intestinal wall of birds, which enhances absorption of nutrients.

• Reduce or eliminate the activity of pathogens causing “subclinical infection.”

• Reduce the growth of microorganisms that compete with the host for supplies of nutrients.

• Antibiotics alter intestinal bacteria so that less urease is produced and thus less ammonia is formed. Ammonia is highly toxic and suppresses growth in poultry (NH3 concentration in poultry shed: <25ppm).

• Antibiotics appear to spare the dietary requirement of the chick for unidentified growth factors.

Probiotics: direct fed microbials

• Live non-pathogenic microbial feed supplement, which beneficially affects the host animals by      improving its intestinal microbial balance, facilitating digestion and absorption.

• Species: Lactobacilli, saccharomyces and Streptococci spp. (30×109 CFU/g)

• Mechanism of action:

• Having a direct effect against undesirable or harmful organisms through production of antibacterial  compounds, eliminating or minimising their competition of nutrients.

• Stimulation of the immune system.

• Neutralisation of toxins formed by pathogenic organisms.

Prebiotics:

• Non-digestible food ingredients that benefit the host by selectively stimulating the growth of desirable bacteria in GIT.

• They modify the balance of the microflora population by promoting the growth of beneficial bacteria &  thereby provide a healthier intestinal environment.

• Examples:

Oligosaccharides (Mannan-oligosaccharides, fructo- oligosaccharides). 

Soya bean meal, rapeseed meal & legumes contain-galactooligosaccharides (GOS)

Cereals contain fructo-oligosaccharides (FOS);

Milk products have trans-galactooligosaccharides (TOS);

Yeast cell walls contain mannan-oligosaccharides (MOS).

Synbiotics: probiotics & prebiotics

Antioxidants:

• Prevent oxidative rancidity of polyunsaturated fats and enhance feed intake

• Example: Vit. E, Se, Ethoxyquin or BHT (butylated hydroxytoluene).

Flavouring Agent:

• Increase palatability and feed intake e.g. Monosodium glutamate (MSG).

• Flavouring agents are needed 

• When highly unpalatable medications are being mixed During attacks of diseases. 
• When animals are under stress 
• With less palatable feedstuffs is being used Food 

Colours:

• Make food more attractive and pleasing.

• Examples: acid fuchsin, brilliant blue, β-carotene, saffron, beetroot red, chlorophyll, etc.

Pigments:

• Examples: Carotenoids/ xanthophyll

• Enhance the colour of the marketed product.

• Colour of an egg yolk due to carotenoids

• Carotenoids in alfalfa produce yellow pigmentation of skin and fat of chicken.

• Xanthophylls are not stable compounds and can be lost by oxidation so antioxidants must be added in poultry feed.

Grit:

• Function: facilitates the digestion and absorption in poultry because poultry do not have teeth to grind any hard grain, most grinding takes place in the thick muscular gizzard for increasing the surface area for digestion and subsequent absorption.

• Oyster shells and limestone are used as grit.

Enzymes:

• Enzymes are biological catalyst

• Examples: beta-glucanase and xylanase, cellulose, Phytase.

• Improve the efficiency of the utilisation of the feed.

• Upgrade cereals by-products or feed components that are poorly digested

• Provide additional digestive enzymes to help poultry to withstand stress conditions.

Antifungal additives:

• Mould inhibitors are added to feed liable to be contaminated with various types of fungi such as Aspergillus and Penicillium spp.

• Propionic, formic acid and acetic acid are added in high moisture grain to inhibit mould growth.

• Antifungals such as Nystatin and copper sulfate preparations are also in use to concentrate feeds to prevent moulds.

Acidifiers:

• As preservative and prevent attaching of microbes with gut walls.

• Organic acids like formic acid, propionic acid, fumaric acid etc. are used as acidifiers

Ionophore antibiotics:

• Ex: monensin, lasalocid, salinomycin

• monensin: streptomyces cinnamonensis

• Rumensin: 50-100 mg/head/day

• Active against G +ve bacteria  fibrolytic bacteria

• Support G –ve bacteria: concentrate digestion- propionate

• Nutrient partitioning agents: phenylethanolamine towards muscle

• Deodorising agents: Yucca Schidigera (block urease no ammonia)

• Methyl donor: methionine, betaine, choline

• Biopreservatives: Nisin produced by Lactococcus lactic- inhibit G-ve and G+ve bacteria.

• Defauning agent: copper sulfate

• Pellet binder: sepiolite

• Buffer: sod. Bicarbonate, MgO

• Mycotoxin binder: zeolite, mineral clay