Nutrients and their Metabolism with Reference to Poultry, Meat and Egg Production | Animal Husbandry & Veterinary Science Optional for UPSC PDF Download

Nutrients and Their Metabolism in Poultry, Meat, and Egg Production

Nutrients: 

• Plants and animals are made up of similar chemical compounds but with varying compositions. These compounds, categorized as nutrients, include carbohydrates, proteins, fats, vitamins, minerals, and water. They are essential for both plant and animal bodies.

Carbohydrates:

• Carbohydrates play a vital role in providing energy to birds. Important polysaccharides like starch, cellulose, and pentosans are part of their diet. While chickens can digest starch, cellulose remains indigestible. Cereal grains are significant sources of starch in poultry feed.

Proteins:

• Poultry products are protein-rich, with broiler carcasses containing over 65% protein. Essential amino acids, the building blocks of proteins, are crucial for protein synthesis. The amino acid composition in the diet must be balanced for efficient protein synthesis needed for tissue repair and egg production.

Fats:

• Fats contribute significantly to the composition of eggs and broiler meat. While essential fatty acids are vital for poultry nutrition, the high cost and potential rancidity of fats limit their direct use. Many feed ingredients naturally contain sufficient amounts of fat to meet the bird's requirements.

Metabolism of Carbohydrate, Protein, and Fat

• The gradual oxidation of absorbed metabolites is the primary mechanism for releasing energy.
• Carbohydrates, proteins, and fats are broken down into pyruvic acid, acetyl-CoA, or a-Ketoglutaric acid, which then enter the Krebs cycle for complete breakdown into CO₂ and H₂O.
• During this process, energy transfers occur, with higher potential systems oxidizing lower potential ones, releasing energy for vital processes.
• The liberated energy is stored in high-energy phosphate bonds and distributed to different tissues for their functions.

Energy and Protein Ration

• The protein level in the diet should be adjusted based on the amount of feed consumed.
• Higher feed intake leads to lower protein proportions and vice versa to maintain a specific protein intake.
• Linking protein concentration with the energy content of the feed ensures a proper energy-protein ratio in the diet.

Factors Affecting Feed Consumption:

• Aside from diet energy content, factors like hen size, breed, environmental temperature, and production stage influence feed intake.
• Feed consumption varies with environmental temperature, reducing in summer and increasing in winter.
• During summer, a laying hen weighing 2 kg consumes 90 g of feed, whereas in winter, consumption rises to 130 g.
• Protein concentration in the diet should be adjusted according to seasonal feed intake variations.

High-Energy Rations for Poultry:

• Commercial poultry farmers commonly use high-energy diets for chicks and broilers for faster growth and reduced feed requirements.
• These diets provide over 900 calories of productive energy per pound and often include low-fibre dehydrated alfalfa.
• Featherpicking issues on high-energy, low-fibre diets can be managed by adjusting lighting or debeaking birds.
• Chickens have limited fiber digestion capabilities, so diets should contain low fiber, typically under 5%.

Fibre Content in Rations: 

• Chicken diets should have low fiber content, usually not exceeding 5%, as chickens struggle to digest fiber efficiently.
• High-energy diets typically contain around 4% fiber to maintain optimal digestion and growth.
• Pelleted rations can support normal growth even with higher fiber content compared to grains, but they require more feed for weight gain.