Abstract: Feed peptides are widely used as a new feed ingredient in animal husbandry. In this paper, the nutrition of small peptides, the absorption mechanism of small peptides in animals and the immune function and intestinal tract of small peptides on piglets. The effects of development are discussed one by one.
Keywords: small peptides, nutritional piglets, immune function, intestinal development,
In recent years, with the development of modern biotechnology, especially modern microbial fermentation technology, small peptide production technology has become more and more, and small peptide products have been widely used as a new feed ingredient or additive for animal husbandry production.
Peptides are linear polymers of amino acids, more than 50 amino acid residues, commonly referred to as proteins, and less than 50 amino acid residues, referred to as peptides. The simplest peptide consists of two amino acid residues, called dipeptides, which contain a peptide bond. It is generally considered in animal nutrition that "a peptide having 2 or 3 amino acid residues is a small peptide".
1 small peptide nutrition
The protein eaten by animals is degraded into free amino acids and various small peptides by digestive enzymes. The free amino acids can be directly absorbed and utilized by animals, and the intact proteins or small peptides produced by their degradation can also be directly absorbed by animals. Small peptides have different absorption mechanisms than single amino acids and are more effective than single amino acid absorption (Rerat et al., 1988).
The absorption of small peptides by monogastric animals is in the mesenteric system, and the small intestine is the main site of peptide absorption, which is completed by small intestinal mucosal epithelial cells (Qi Lili et al., 2003).
2 absorption mechanism of small peptides in animals
Studies have shown that small peptides can be absorbed into the circulatory system more and faster. In addition, the absorption of dipeptides in the small intestine of piglets also shows that the rate of lysine uptake in dipeptides is much higher than that in free amino acid mixtures. Acid intake. Therefore, the absorption mechanism of small peptides is different from that of amino acids, mainly in the low energy consumption of peptide transport, fast transport, and the carrier is not easy to be saturated. It has more advantages in absorption than free amino acids.
Classical nutrition believes that the protein of animal diets is degraded into small peptides and free amino acids in the digestive tract by proteases and peptidases. Free amino acids can be directly absorbed and utilized by animals, and small peptides can only be further degraded into free amino acids. In the early 1960s, Neway and Smyth (1960) found that the digestion products of proteins in the small intestine had a large number of small peptides in addition to amino acids, and the peptides could enter the intestinal mucosal cells intact; Adibi (1978) used electromagnetic probes. The final products of the detected proteins are small peptides and amino acids; these provide further support for the absorption mechanism of small peptides. Therefore, there is
Some scholars have proposed that the complete protein or the small peptide produced by its degradation can also be directly absorbed by animals, so the research on the nutrition of small peptides has begun to receive attention. Subsequent studies have shown that most of the degradation products of proteins in the digestive tract are small peptides (mainly dipeptides and tripeptides) that are absorbed into the circulatory system in intact form for tissue utilization.
2.1 Absorption mechanism in monogastric animals
The protein diet is degraded into free amino acids and small peptides by the action of enzymes in the digestive tract of animals. The transport mechanism of small peptides may have the following three forms: 1 pH-dependent hydrogen ion and sodium ion transport system, no consumption ATP; 2 active transport process dependent on hydrogen ions or calcium ions, need to consume ATP; 3 glutathione (GSH) transport system.
2.2 Absorption mechanism in ruminants
Webb (1993) proposes that the absorption of amino acids and peptides exists in both the mesenteric system and the non-mesenteric system. Small peptides absorbed by the jejunum, colon, ileum, and cecum enter the mesenteric system, while small peptides absorbed by the rumen, valvular, reticulum, abdomen, and duodenum enter the non-mesenteric system.
3 peptide absorption advantage
The absorption of small peptides has the advantages of low energy consumption, fast transport speed, and low saturation of the carrier. The absorption of free amino acids is slow, the carrier is easy to be saturated, and the energy consumption during absorption is large. Some scholars believe that the absorption capacity of peptide carriers may be higher than that of various amino acid carriers. The sum of absorption capacity, and the infusion experiment of the mixture of duodenal small peptides in pigs, chickens and other animals showed that the absorption rate of the small peptide mixture was significantly higher than that of the amino acid mixture. The reason why the amino acid residue in the small peptide is rapidly absorbed is that, in addition to the peptide absorption mechanism itself, it may be that the peptide itself promotes the absorption of the amino acid or its residue. According to reports by Bamba et al., using small peptides as a substrate to make the intestinal brush border membrane
The aminopeptidase activity and amino acid number of the vesicle (BBMV) are increased in vector and activity.
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