Concepts and classification of peptides

Peptide is a kind of compound whose molecular structure is between Amino Acid and Protein. Amino acid is the basic unit of peptide. Those containing more than 50 amino acid residues are usually called proteins, those containing less than 50 amino acid residues are called peptides, those containing less than 10 amino acid residues are called oligopeptides, and those containing 2 or 3 amino acid residues are called small peptides, namely commonly known as dipeptides and tripeptides.

Peptides can be divided into two broad groups according to the functions they perform: Functional peptides and nutritional peptides. Functional small peptides are small peptides that can regulate some physiological activities of animals or have some special functions. They can also be called bioactive peptides. Nutritional small peptides are small peptides that only provide nitrogen scaffolds for protein synthesis without special physiological regulatory functions.

Nutritional and physiological functions of small peptides

The digestion and absorption efficiency and utilization efficiency of protein were significantly improved. The overall protein precipitation efficiency of the diets with small peptides as nitrogen sources was higher than that of the diets with amino acids or whole proteins as nitrogen sources.

Promote the absorption and utilization of mineral elements. Some small peptides have the properties of binding to metals, and can form chelates with Ca, Zn, Cu and Fe plasma to increase their solubility, thus promoting the passive operation process of Ca, Zn, Cu and Fe and their storage in vivo.

Physiological regulation：a. Immune regulation b. Antioxidant function c. Neuroregulation D. Some growth promoting peptides have the function of promoting animal growth E. Improve the palatability of feed, some peptides can promote sour, sweet, bitter, salty taste. Some peptides are also used as chemical attractants in fish feed. Peptides can be designed and used to improve palatability by mimicking, masking, or enhancing taste.

Excerpt from "Practical Manual of Feed Additives" Chemical Industry Press