Fish meal is too weak, want to use small peptide, what is small peptide?

Fish meal is so expensive that we can't afford it, and we don't want users to say anything. I'd like to add some substitutes. I heard that the small peptide is good, so I want to use it, but I can ask that the standard of this small peptide is CP. I would like to ask how can we know the content of this small peptide, and how did this small peptide come from? The prawn expressed his opinion. -- if you don't believe it, there are still so many people using it, and you're afraid that others will run faster and harder than yourself. anyone who has used it or has done an experiment can help. I don't have a testing ground. -- Fish meal is too weak and wants to use small peptides, but fish meal and small peptides are two different things-- Research Progress on absorption Mechanism and Nutrition of small peptides

Li Lusheng (College of Agriculture, Liaocheng University, 252000, Liaocheng, Shandong)

Feng Dingyuan (School of Motion Sciences, South China Agricultural University, Guangzhou 510640)

Abstract in recent years, studies have shown that small peptides are the main digestive products of proteins and play a very important role in the digestion, absorption and metabolism of amino acids. This paper reviews the absorption mechanism of small peptides in monogastric animals and ruminants, the nutritional role of small peptides and the factors affecting the absorption of small peptides, as well as the role of small peptides in protein metabolism.

Key words absorption mechanism of free amino acids in small peptides

Protein is one of the most important nutrients in animal nutrition, and there are many studies on its absorption mechanism. In the past, it was believed that the digestive tract of animals could only absorb free amino acids, that is, proteins had to be broken down into free amino acids before they could be absorbed. However, in recent years, some experiments have proved that the best production performance and feed efficiency can not be achieved when the animals are fed a homozygous diet or a low-protein amino acid balanced diet. Therefore, some scholars believe that the digestive tract of animals not only can absorb free amino acids, but also have special needs for proteins or peptides. Neway and Smith first put forward the idea that small peptides can be transported and absorbed completely in 1960. Since then, most of the hydrolyzed end products of proteins in the digestive tract are small peptides composed of 2 or 3 amino acid residues, which can be absorbed into the circulatory system in complete form and then used by tissues. Type I vector [1] and type II vector [2] of small peptides were cloned respectively. In recent years, great progress has been made in the research on the absorption mechanism, carrier and physiological characteristics of small peptides in animals. The view that small peptides can be completely absorbed in animals has been further confirmed and developed.

1 absorption mechanism of small peptides

1.1 absorption mechanism of small peptides in monogastric animals

The absorption mechanism of small peptides is completely different from that of free amino acids. There are four kinds of systems for the absorption of free amino acids: neutral, acidic, basic amino acids and sub-amino acids. The reverse concentration transport of these four systems mainly depends on different Na+ pumps, which is an active transport process. At present, the transport mechanism of small peptides is not very clear, and there may be three forms: ① needs to consume the active transport process of ATP [4], and depends on hydrogen ion concentration and calcium ion concentration for conductivity. This mode of transport is inhibited by hypoxia or the addition of metabolic inhibitors. The second type of ② is a PH-dependent exchange and transport system of sodium ion, which does not consume ATP [5]. Daniel et al. (1994) found that the power of small peptide transport comes from the electrochemical gradient of protons, and the driving force of proton movement is caused by the activity of the Na + channel in the tip cell of the brush margin: the proton transport into the cell drives the small peptide to move into the cell. In this way, the small peptides enter the cell in the form of facilitation and diffusion, resulting in a decrease in the pH value of the cytoplasm; thus activating the Na+/H+ channel, H + is released from the cell, and the intracellular PH is restored to the original level. The third type of ③ is glutathione (GSH) transport system. Due to the antioxidant effect of glutathione in biofilm, GSH transport system may have special physiological significance, but its mechanism is not very clear. Vincerzini (1989) reported that the transmembrane transport of GSH is related to the concentration gradients of Na+, K +, Li+, Ca+ and Mn+, but has nothing to do with the concentration of H +.

1.2 absorption mechanism of ruminants

The absorption of small peptides by ruminants is different from that of monogastric animals. According to the study, it is found that there are two sets of absorption systems in ruminants, mesenteric system and non-mesenteric system [7]. In general, the absorption of small peptides in the digestive tract in the rumen, reticulum, valve, abomasum and duodenum is carried out in the non-mesenteric system, while in the jejunum, colon, ileum, cecum and other parts in the form of mesentery. Dirienzo (1990) determined the absorption of amino acids and peptides in sheep. The free amino acids absorbed from the mesentery were 36.74g/d, the amino acids absorbed in the form of peptides were 52.01g/d, and the amounts absorbed from non-mesentery were 4.51g/d and 308.40g/d, respectively. Thus it can be seen that the non-mesenteric system is the main way of peptide absorption. When Matthews (1991) studied the absorption of small peptides by rumen epithelial cells and valvular epithelial cells in vitro, it was found that the absorption of small peptides by rumen epithelial cells and valvular epithelial cells was an unsaturated passive diffusion process, and the ability of rumen epithelial cells to absorb small peptides was stronger than that of rumen epithelial cells.

1.3 characteristics of absorption mechanism of small peptides

Compared with free amino acids, the transport system of small peptides has the characteristics of low energy consumption, fast transport speed and not easy to be saturated [8], while the transport speed of free amino acids is slow, high energy consumption and carriers are easy to be saturated. A large number of experiments have confirmed that most of the amino acid residues of peptides formed in the intestinal tract are absorbed more quickly and effectively than single amino acids. Rerat et al. (1988) observed that when the mixture of peptides was injected into the duodenum, except methionine, the amino acids in the portal vein appeared earlier than the corresponding mixture of amino acids, and the absorption peak was higher, indicating that the absorption rate of the mixture of small peptides was high. Le Guowei et al (1997) reported that when CSP (enzyme-hydrolyzed casein mainly composed of small peptides) and the corresponding mixture of free amino acids were infused into the duodenum of chickens, the amounts of some small peptides and total peptides in portal vein circulation in CSP group were significantly higher than those in FAA group 10 minutes later. Daneil et al. (1994) suggested that the absorption capacity of peptide carriers may be higher than the sum of the absorption capacity of various amino acid carriers. The reason for the rapid absorption of amino acid residues in small peptides, in addition to the absorption mechanism of small peptides, may be that small peptides can promote the absorption of amino acids or their residues. As the absorption substrate of intestinal cavity, small peptides can not only increase the activity of brush margin aminopeptidase and dipeptidase, but also increase the number of small peptide carriers [9].

2 the nutritional effect of small peptides

2.1 increase the utilization rate of dietary amino acids

There is a competition for the absorption of free amino acids in the digestive tract, and the absorption mechanism of small peptides is completely different from that of free amino acids. Many experiments show that the addition of small peptides can improve the absorption rate of amino acids and promote the utilization of dietary amino acids. The inhibition of arginine on the absorption of lysine was obvious in the form of favorable and partial small peptides, and the absorption rate of lysine was not affected by arginine when supplied with small peptides. Pharagyn and Barley (1987) reported that when lysine and arginine exist in free form, they compete with each other for absorption sites. Free arginine tends to decrease the level of lysine in hepatic portal vein, while arginine has no effect on its absorption when lysine exists in peptide form. When Shi Yonghui et al (1996) studied the effects of different ratios of small peptides and free amino acids on the absorption of amino acids in chickens, it was observed that the increase of the proportion of small peptides could significantly increase the absorption rate of amino acids, while increasing the proportion or concentration of free amino acids in the perfusion solution could not accelerate the absorption of most amino acids.

2.2 increase the deposition rate of protein in the body

The existence of amino acids in diet affects the metabolism of protein in animals. Some animal nutrition experiments have observed the role of small peptides in animal protein deposition. Infante et al (1992) reported that when nitrogen was supplied in the form of small peptides or free amino acids and complete protein, the nitrogen deposition of rats in dipeptide and tripeptide diets was the highest, free amino acids were poor, and complete protein was in the middle. Le Guowei (1996) observed that the tissue protein synthesis rate of chicks perfused with casein hydrolysate peptide was significantly higher than that of the corresponding free amino acid mixture group. Funabiki (1992) also observed that the body protein synthesis rate of the peptide diet group was 26% higher than that of the corresponding amino acid diet group. Rerat et al (1988) reported that after infusing small peptides into the duodenum of pigs, the concentration of plasma insulin was higher than that of free amino acids, and one of the physiological functions of insulin was to participate in the extension of peptide chain in protein synthesis and increase protein synthesis.

2.3 promote the absorption and utilization of mineral elements

Some small peptides have the property of binding to metals, which can promote the passive transport and storage of metal elements in the body. In the hydrolysate of casein, there is a kind of phosphorylated serine residues which can bind with calcium ion and ferrous ion, which can improve their solubility. Meiser et al. (1980) isolated opioid peptides from bovine casein and obtained a phosphopeptide, referred to as casein, whose serine hydroxyl groups are almost phosphorylated. These phosphopeptides concentrate a large amount of negative charge, can prevent further protein hydrolysis, and can combine free calcium, iron, copper, zinc and other metal ions to form soluble salts to increase their concentration in the intestinal cavity and promote the passive transport of these ions. Shi Yonghui et al (1996) reported that after adding small peptide products to the diet of laying hens, the contents of iron and zinc in plasma were significantly higher than those in the control group, and the strength of eggshell was improved.

2.4 nutritional effect of small peptides on Rumen microorganisms

Ha (1996) reported that one hour after sheep were fed with rice straw and concentrate at the ratio of 1 ∶ 1, the concentration of peptides in the rumen increased by 2.5 times, and then decreased in a straight line. The results showed that most of the feed protein was used by microorganisms after the feed protein was rapidly decomposed into peptides. Arggde (1989) found that about 2% of the ammonia needed for rumen microbial protein synthesis came from peptides and amino acids. Peptide is an important substrate for protein synthesis by rumen microorganisms. The main effect of peptides on the growth of rumen microorganisms is to accelerate the reproduction of microorganisms and shorten the cell division cycle [10]. In particular, small peptides can stimulate the microbial growth of fermented sugars and starches. CruzSoto et al. (1994) pure culture of rumen microorganisms showed that when soluble sugars such as glucose and cellobiose were used as energy sources, the growth rate of soluble sugar-decomposing bacteria promoted by small peptides was 70% higher than that of amino acids, while the growth rate of cellulose-decomposing bacteria was the same under the conditions of ammonium chloride, mixed amino acids and peptides.

Although the mechanism of transport and utilization of small peptides by rumen microorganisms is not clear, it has been proved that small peptides are the key factors for the maximum growth efficiency of rumen microorganisms, but whether small peptides can promote the growth of microorganisms mainly depends on the fermentation rate of carbohydrates as energy. For soluble sugars with fast fermentation rate, small peptides can promote the growth of microorganisms, while for cellulose substances with slow fermentation rate, small peptides can not promote the growth of microorganisms. This is also the core of the established rumen microbial peptide nutrition system [11].

2.5 improve the growth performance of animals

Some proteins are degraded under the action of digestive enzymes to produce many small peptides with certain peptide chain structure and amino acid residue sequence, which may have special physiological activities and can be directly absorbed by animals. participate in the physiological activity and metabolic regulation of the body, so as to improve its production performance. Parisini et al. (1989) significantly increased daily gain, protein utilization and feed conversion rate of growing pigs after adding a small amount of peptides to the diet. Shi Yonghui et al (1996) reported that after adding peptide products to the basic diet of laying hens, the laying rate and feed conversion rate were significantly increased, and the eggshell strength also tended to increase. Pocius et al. (1981) observed that glutathione (tripeptide) in the blood can be used by breast tissue, and cysteine from glutathione can meet the needs of milk production. Other studies have shown that free cysteine in the blood cannot be used to synthesize milk proteins.

Other physiological activities of 3 small peptides

Small peptides not only promote the absorption of amino acids and provide amino acids themselves, but also have many important physiological functions. There are also a lot of studies in this area, especially on tyrosine hydrolysates. Brantl et al. (1979) proved that the glycolysis products of bovine lactoprotease have the activity of opioid peptides. After a large number of studies, people have found many small peptides with special physiological functions, called physiologically active peptides, including antiviral and anticancer peptides, antibacterial peptides, growth-promoting peptides, immunomodulatory peptides, seasoning peptides, antioxidant peptides and environmental protection peptides. These physiologically active peptides play an important role in anti-virus and antibacterial, promoting growth, immune regulation, improving palatability and protecting the environment.

4 summary

The nutritional effect of small peptides has been confirmed by many experiments, but how small peptides participate in nitrogen metabolism and what are the requirements of livestock and poultry? under the current theory that animals need complete proteins to meet the needs of oligopeptides, how to re-evaluate the ideal protein model based on available amino acids. Further discussion is needed.

"small peptides are 2 or 3 amino acid residues". Is the feeding effect of leucine residues the same as that of lysine residues? Is the residue a complete amino acid after hydrogenation? What is the nutritional essence of small peptides? Is there any relationship between the nutrition of small peptides and amino acids? Is there any part of protein feed used in the form of small peptides in the process of digestion and absorption?

How do small peptides be used in formulations? Is it added according to a certain proportion, or is it calculated according to the amount required? .

It seems that there is still a certain distance for small peptides to reach universal use, and all their metabolic processes have not yet been fully understood. Good things should be more stable, and early development often has negative effects, just like nano-feed.

Small peptides have been studied a lot at home and abroad, and there are a lot of materials. It has been said that it is a new thing for several years, and it is not very clear and difficult to understand it.

In fact, small peptides are really a good thing, with fast digestion and absorption and high utilization, and some special small peptides also have their unique functions. This is definitely a development direction in the future.

But the most important thing is that the understanding of it is still too superficial and has not yet reached a practical stage, and the production method and production process can not be controlled. The test doesn't seem to work either. Anyway, he said it was a small peptide, and you don't know exactly what it is. As far as I know, Nestl é is using Harbin Leneng products, you can have a look on the website of Leneng Peptide! In fact, small peptides are really a good thing, with fast digestion and absorption and high utilization, and some special small peptides also have their unique functions. This is definitely a development direction in the future.

Well, it could be a good thing. In theory, the absorption process is clear, and the actual effect is clearer (including various animal products), but no one seems to have come up with a theoretical basis for the protein reorganization process after absorption, whether it is meat, milk, or eggs. This is the essence of small peptide nutrition, without which we can only use it blindly. If the domestic products are produced by hydrolysis of fish protein, is the effect of hydrolysis of useful soybean protein the same? If the small peptide is used as an additive, it is easy to understand, if it is used as the main protein raw material, how does he calculate it?

Really know too little, who can explain him clearly. -- small peptides are good things. the question is whether they are real small peptides on the market. It is better to be cautious before they are understood. Use raw materials clearly!-- Yes, small peptides are very good in theory. However, when it comes to promotion, I always feel that I can't accept it. People who do small peptide business are talking about a concept, but we can't see how much that small peptide should actually be used, and we always feel a little empty. It's better to actually use fishmeal, it's a little more expensive, but it's better than harming the farmer elder brother who works hard below.