Proteins

Protein Structure and Function

• Proteins are formed by amino acids linking together to create a complex 3D structure.
• Animals use 21 of the many amino acids to create proteins.
• Proteins are crucial for all bodily tissues and organs.
• Proteins are fundamental to cell structure, playing a role in cell walls.
• They're vital for tissue growth, repair, and maintenance.
• Dietary protein provides essential amino acids.
• Protein is crucial for synthesizing non-essential amino acids.
• Amino acids are essential for building, repairing, and replacing body proteins.
• Excess protein is converted to glycogen and potentially stored as fat.

Protein Functions in the Body

• Proteins are involved in many bodily functions, including:
  • Providing structure to cartilage, tendons, and ligaments.
  • Enabling muscle contraction.
  • Forming skin, hair, and nails (keratin).
  • Creating blood proteins (albumin, globulins, hemoglobin).
  • Producing enzymes, hormones, and antibodies.

Essential, Non-Essential, and Conditionally Essential Amino Acids

• Amino acids are categorized into essential (must come from diet), non-essential (body can synthesize), and conditionally essential (needed in specific situations).
• Dogs require 10 essential amino acids, and cats require 11.
• Key essential amino acids for dogs: Arginine, Histidine, Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Threonine, Tryptophan, and Valine.
• Key essential amino acids for cats: Same as dogs plus Taurine.

Taurine

• Taurine is a conditionally essential amino acid critical for cats.
• It's not synthesized by cats and is vital for retinal function, and myocardial function.
• It's found predominantly in animal tissues.
• Diets high in plant-based proteins may not provide sufficient taurine in cats, particularly if the diet is largely dry food.
• Canned cat food often has a higher taurine requirement due to the heat-processing effect on protein.

Protein Quality and Source

• Protein quality varies based on the completeness and digestibility of the protein source.
• High-quality proteins provide essential amino acids in the correct proportions.
• Low-quality sources may lack sufficient quantities of specific amino acids.
• Cooking methods, temperature, and fiber content can affect the digestibility of protein sources.
• Animal-based proteins are generally considered higher quality.

Protein Deficiency Symptoms

• Deficiencies of essential amino acids can lead to:
  • Impaired growth.
  • Weight loss.
  • Dull coat.
  • Weakened immunity.

Protein Storage and Energy

• The body stores excess protein as dietary energy (fat) if caloric intake exceeds energy requirements.

Biological Value of Protein

• Biological value (BV) measures the body's ability to utilize absorbed protein.
• High BV proteins require less intake to meet amino acid needs.

Protein Sources in Diets

• Various animal and plant-based proteins are used: beef, chicken, pork, eggs, fish, various plant-based proteins (pea, potato, rice, soybeans).
• Organ meats and animal byproducts are common and contribute to sustainable practices by using otherwise wasted materials.

Protein Requirements

• Cats generally have higher protein requirements than dogs.