Sources of Protein | Animal Husbandry & Veterinary Science Optional for UPSC PDF Download

Sources of Protein Overview

• Farm feeds contain varying amounts of proteins.
• Succulent feeds like turnips, cabbage, and kale have low protein content (not exceeding 1-2%).
• Coarse fodders such as oats and barley straw also fall in the low protein category.
• Grazing animals can fulfill their protein needs from green grass in various forms (fresh, hay, or silage).
• Pasture grass typically contains more than 2% protein.
• Protein content in hay ranges from 3-8% or even higher.
• Silage usually contains 1-3% protein, which can increase with a higher legume percentage.
• Home grain concentrates have protein levels ranging from over 7% in oats and barley to nearly 10% in wheat.
• Beans and peas are rich protein sources with around 20% protein content.
• The highest protein content is usually found in the seeds of plants.

Protein Elaboration Process

• Protein synthesis starts in the leaves where carbon, hydrogen, and oxygen from sugar combine with nitrogen and other elements absorbed by the roots from the soil.
• Young leafy grass has a high protein content due to this process.
• As plants mature, protein shifts to reproductive parts like seeds.
• After flowering, the feeding value of stems and leaves decreases, while seeds become protein-rich.

Protein Sources in Animal and Plant Feeds

Impact of Seed Processing on Protein Content:

• When the non-protein part of a seed is removed, the protein content of the remainder increases proportionately.
• For instance, oil-bearing seeds like cottonseeds have their oil extracted, resulting in residues sold as cotton cake. These residues have a higher protein content, making them valuable farm feeds.

Vegetable Origin Feeds:

• By-products of extraction processes, such as wheat feeds like bran and outer seed coat layers, are part of this category.
• These wheat by-products contain around 10 to 12% protein, which is higher than the protein content found in the whole grain.

Animal-Derived Proteins:

• Another essential protein source comes from animals.
• Popular feeds in this group include fish-meal, comprising fine inedible fish parts, and various meat and bone-meals from slaughterhouses.
• These animal-derived feeds are highly valuable due to their rich protein content sourced from animals.
• A certain portion of animal protein in the feed is deemed necessary.

Protein in Animal Nutrition

• Importance of Protein in Animal Body: Proteins are crucial for animals as their bodies are predominantly made up of protein. The daily requirement for protein is relatively high as it is essential for repairing worn-out tissues and building new ones.
• Protein Requirements: Youthful animals have particularly high protein needs as they are developing muscle tissue or lean meat, which consists mainly of protein. As animals mature, their protein requirements decrease relative to their size, except during periods such as reproduction or milk production when demands increase.
• Function of Protein in Food: The primary function of protein in food is to provide animals with a variety of amino acids necessary for building their own body proteins.
• Essential Amino Acids: Some amino acids cannot be produced by the animal's body and must be obtained through diet. These essential amino acids (about a dozen in number) are crucial for preventing malnutrition in animals.
• Importance of Animal Proteins: Proteins of animal origin are vital as they contain the required amino acids in appropriate quantities. Animal proteins are highly efficient for animals, have high biological value, and are essential for meeting the animals' nutritional needs.