Livestock Nutrition (Proteins)

Proteins

  • Essential constituents of living organisms, formed by long chains of amino acids (aa).

  • Comprised of 20 standard amino acids with specific structures and functions.

  • Characteristics: Water-soluble, contains C, H, O, N; some have S and P.

Amino Acids

  • General formula includes amino group (NH2) and carboxyl group (COOH).

  • R group is unique to each amino acid, determining properties.

  • 20 Amino Acids List:
      - Ala: Alanine, Leu: Leucine, Arg: Arginine, Lys: Lysine, Asp: Aspartic acid
      - Met: Methionine, Asn: Asparagine, Phe: Phenylalanine, Cys: Cysteine
      - Pro: Proline, Gln: Glutamine, Ser: Serine, Glu: Glutamic acid
      - Thr: Threonine, Gly: Glycine, Trp: Tryptophan, His: Histidine
      - Tyr: Tyrosine, Ile: Isoleucine, Val: Valine

Protein Structure

  • Proteins are polypeptides formed via peptide bonds (condensation reactions between aa).

  • Bonds include hydrogen, ionic, hydrophobic interactions, and disulfide bonds.

  • Denaturation: Loss of structural shape due to weaker bonds breaking.

Protein Evaluation

  • Evaluated by CP content via the Kjeldahl method.

  • Essential amino acids cannot be synthesized by the body; must be ingested.
      - Key: Lysine, Methionine, Arginine, Leucine, Isoleucine, Phenylalanine, Threonine, Tryptophan, Valine.

  • Non-essential amino acids can be synthesized.

Protein Digestion

  • Initiated in the stomach by HCl and pepsin, leading to proteolysis.

  • Further breakdown occurs in the small intestine (SI) via proteolytic enzymes: Pepsin, Trypsin, Chymotrypsin, Amino peptidases.

  • Absorption occurs as mono- and di-peptides.

Amino Acid Metabolism

  • Pathways:
      - Deamination: Removal of amino group for energy, resulting in urea production.
      - Transamination: Transfer of amino groups to alpha-keto acids, synthetizing non-essential amino acids.

Essential Points

  • Proteins are crucial for body functions, nutrition, growth, and reproduction.

  • Protein requirements are based on the animal's maintenance, growth, and production needs.

  • High biological value proteins are essential in diets to meet amino acid needs.

I can't add pictures directly to the notes, but I can suggest using diagrams or images that illustrate protein structures, amino acid structures, and protein digestion processes. You can find relevant images in educational resources, textbooks, or online databases dedicated to biology and biochemistry.