What are the aquafeed additives?
1, live bacterial preparations
Live bacterial preparations are animal beneficial bacteria produced by industrialized anaerobic fermentation of bacterial agents. Live bacterial preparations on the role of aquatic animals can be briefly summarized as follows: live bacterial preparations of beneficial microorganisms into the aquatic animal body, the formation of dominant flora, and harmful bacteria compete for oxygen attachment sites and nutrients, competitive inhibition of the growth of harmful bacteria, so as to regulate the intestinal flora tends to normalize; microbial metabolism produces organic acids, reduce the pH value of the intestinal tract, kill acid-resistant harmful bacteria; production of lysozyme, Hydrogen peroxide and other substances, can kill potential pathogenic bacteria; produce a variety of digestive enzymes, is conducive to the decomposition of nutrients; synthesize B vitamins, amino acids, unknown growth-promoting factors and other nutrients; directly stimulate the intestinal immune cells and increase the local immune antibodies, enhance the body's resistance to disease.
Live bacterial preparations used in aquaculture, characterized by the following three aspects: the first is the diversity of functions, it has a growth-promoting effect, to improve fish, shrimp, crabs and other aquatic products, according to the report: can improve the yield of 10 to 30%; improve the quality of aquatic products; with a variety of functions, such as prevention of disease and disease resistance. Can improve the survival rate of fish species 5 to 20%; the second is a wide range of adaptability, the existing aquatic live bacterial preparations in Sichuan, Liaoning, Guangdong and other places of experimental demonstration, have shown significant results. The main reason for this is that it is mainly affected by the aquatic organisms individual live bacteria environment, the external environment on its role is relatively small. At present, there are only a small number of domestic and foreign reports on shrimp, fish-specific live bacterial preparations; the third is a high degree of security, aquatic live bacterial preparations are mostly from the microbial system in the body of a healthy aquatic animal to isolate, purify, and then act on the aquatic animal, will not produce any harm to the aquatic animal, and will not be in the water and the fish body has a residue.
2. Sugar terpenes
Sugar terpenes are natural bioactive substances composed of sugars (≥30%), ligands (≥30%) and organic acids. Sugar terpenes active ingredients performance is stable, the use of safe, and other feed additives are not contraindicated. Sugar terpenes in the feed additive amount of 200-500 g / ton, it can completely replace the antibiotic drugs, and no residue, no pollution of the environment, feeding, can significantly enhance the body of aquatic animals immunity and resistance to disease, to promote growth, improve the daily weight gain and feed conversion rate, and anti-stress, antioxidant effect; at the same time on the intestinal bacterial disease has a strong preventive effect. According to the test, fed with sugar terpene feed additives for aquatic products, the quality has been improved, in line with the green production requirements of animal-derived food, social and economic benefits are very significant.
3, oligosaccharides
Oligosaccharides, also known as oligosaccharides, is a general term for oligosaccharides with straight or branched chain structure connected by 2-10 sugar groups through glycosidic bonds. There are many types of oligosaccharides, but the ones currently used as feed additives mainly include: isomaltose, isomaltotriose, isomaltotetraose, panose, fructo-oligosaccharides, fructo-oligosaccharides, fructo-oligosaccharides, fructo-oligosaccharides, galacto-oligosaccharides, mannan-oligosaccharides, soybean-oligosaccharides, gentian-oligosaccharides, xylo-oligosaccharides and so on. Oligosaccharides can selectively promote the proliferation of beneficial bacteria in the intestinal tract of aquatic animals. These beneficial bacteria utilize oligosaccharides to produce short-chain fatty acids by fermentation, lowering intestinal pH, inhibiting pathogenic bacteria from consuming nutrients in the body, and reducing the production of toxic and disease-causing metabolites, thus maintaining and enhancing the health of aquatic animals.
Some oligosaccharides can improve the body's immune response to drugs and antigens, and enhance the immunity of aquatic animals. Compared with live bacterial preparations, oligosaccharides are more stable and highly tolerant to harsh environmental conditions such as granulation, expansion, oxidation and storage and transportation, and can resist the inactivation of gastric acid, overcoming the defects of live bacterial preparations that are difficult to colonize in the intestinal tract. Plus it is non-toxic and has no side effects.
4, enzyme preparations
Enzyme preparations are processed through a specific production process containing a single enzyme or a mixture of enzyme industrial products. At present, in addition to phytase has a single enzyme products, the rest of the feed enzyme preparations mostly contain a variety of enzyme composite preparations. Application of more cellulase, β-glucanase, xylanase, amylase, protease, pectinase, phytase and so on. Part of these enzymes can be secreted by the aquatic animals themselves, such as amylase and certain proteases; while the other part of the aquatic animals themselves can not be secreted, such as cellulase, β-glucanase and xylanase can not be secreted. Enzymes can break down plant cell walls, by breaking down cellulose, hemicellulose and pectin, which are made up of non-starch polysaccharides (NSPs), not only to break down these unavailable polysaccharides into small-molecule sugars that can be digested and absorbed, but also to expose nutrients, such as starch and proteins, which are protected by the cell walls, so as to make them more adequate nutrients. Enzymes can also reduce the viscosity of sticky chowders caused by soluble NSP. Enzymes can also destabilize the stable phytate-phosphorus structure, increasing the utilization of phosphorus and other nutrients in the feed.
Feeding enzyme preparation applied to aquaculture has four main functions: to promote feed digestion and absorption, to promote the aquatic animal feeding and growth; has to improve the function of the digestive system and a certain anti-inflammatory effect; to prevent and slow down the stress response of the aquatic animal; to improve the effect of the feed, reduce the content of nutrients in the excreta.
5, herbal feed additives
In recent years, Chinese herbs due to the absence of resistance and drug residues, side effects, small, effective, resource-rich and other advantages of people's attention. Herbs contain nutrients such as proteins, amino acids, vitamins, oils, resins, sugars, plant pigments, macronutrients and trace elements, and also contain a large amount of organic acids, alkaloids, polysaccharides, volatile oils, waxes, tannins, and a number of unknown growth-promoting active substances.
According to another study, Chinese herbs also contain a variety of immune active substances. The role of herbal additives in aquaculture is mainly manifested in the following four aspects: to promote aquatic animal feeding (enticement), increase the amount of food; reduce the bait coefficient, increase the weight gain rate; prevention and control of fish disease, improve the survival rate; replace some of the mineral salt additives and vitamin additives.
6, yeast cell wall
Yeast cell wall is a new natural green additives, its products for the egg yellow powder, is the production of brewer's yeast in the process of soluble substances extracted from a special by-products, mainly composed of β-glucan, mannan oligosaccharide, glycoprotein and chitin, accounting for about 85% of the dry weight of the cell wall. Studies have shown that yeast cell wall has physiological effects such as stimulating and enhancing immune function; maintaining the balance of live bacteria and controlling diseases. Aquatic animals not only face the stress of water environment changes, but also suffer from a variety of common diseases, conventional disease control measures are limited, and low-dose yeast cell wall added to aquatic feed, you can enhance the fish, shrimp, soft-shelled turtles, crabs, etc. on a variety of major diseases and environmental changes in resistance to improve the survival rate.
Healthy fish, shrimp feeding yeast cell wall can improve the survival rate of seedlings 20% -40%, to improve the survival rate of the growth period 10% -20%. Therefore, the use of yeast cell wall special feed is considered to be an effective means of strengthening the resistance of aquatic animals to disease and promoting growth.
7, carnitine
Carnitine, also known as carnitine, was originally discovered by Krimberg and Gulewitsch in 1905 in muscle extracts. There are two variants of carnitine, left (L-type) and right (R-type), and only left carnitine exists in nature. Carnitine is a water-soluble compound, which has a great effect on human beings and animals, and is an essential life active substance for living organisms. In recent years, some studies have been conducted at home and abroad on the effect of carnitine on the growth performance of aquatic animals, and most of the research results show that carnitine has the following four effects on aquatic animals: improve the weight gain rate of aquatic animals; reduce the body fat of aquatic animals and improve the quality of meat; conserve feed protein, reduce the bait coefficient, improve the survival rate of aquatic animals; and improve the reproduction rate of fish.
The efficacy of commonly used aquatic feed additives
1, betaine
Choline is the raw material for the synthesis of phospholipids, phospholipids are conducive to the digestion and absorption of fatty acids to prevent the occurrence of fatty liver. Because betaine can provide methyl to aminoethanol to generate choline, so betaine also has the effect of preventing fatty liver disease. At the same time, due to the methylation reaction carried out by betaine in the liver, it provides methyl for the synthesis of phosphatidylcholine, and methyl can promote fat metabolism, promote the operation of liver fat, and prevent the accumulation of fat in the liver. According to the Jiangxi Ganjiang Regional Aquatic Research Institute, betaine has a significant effect on lowering the fat content of the liver of grass carp, and in the case of grass carp fed with compound feed for a long period of time without green fodder supplementation, the addition of betaine can be very good to prevent fatty liver disease caused by nutritional deficiency.
2, choline
Choline deficiency is one of the important causes of fatty liver in animals. Choline in the animal body, is the raw material of all-sheng lecithin, choline in the form of lecithin to promote fat transportation or in the process of improving hepatic fat metabolism until the key role. When rainbow trout are deficient in choline, they have protruding eyes, swollen abdomens, yellow and greasy livers, enlargement, anemia, and slow growth from the 15th day onward. In the case of choline deficiency in carp, in addition to fatty liver, the growth rate is also slowed down. According to the test, when the spotted fork-tail _ feed lack of choline, can be seen in the liver hemorrhage, liver greasy hypertrophy, weight loss.
3, phospholipids
Phospholipids from animal and plant fats and oils, its molecular structure is similar to natural fats and oils, belonging to the glycerol ester class. From the point of view of nutritional properties, phospholipids and fats and oils, can provide glycerol and fatty acids and other components, in addition to providing phosphoric acid, choline and inositol and other components, and has a water-soluble vitamins of certain properties. Soybean phospholipids and canola oil phospholipids are commonly used in aquaculture. Soybean phospholipids and canola oil phospholipids contain oil, phospholipids, glycolipids, vitamin E and other nutrients and energy.
Phospholipids and its contained choline, vitamin E and other substances are the main substances to prevent fatty liver disease in animals. This effect has been confirmed in aquaculture. The Shanghai Scientific Research Institute of Fats and Oils (1982-1984), in collaboration with the Shanghai Fisheries Research Institute and other units, used rapeseed oil phospholipids as additives for pond fish with bait, and the results proved that rapeseed oil phospholipids have the effect of increasing production, saving material and improving the net return of mu for freshwater fish (mackerel, grass carp, groupers), which is considered to have the effect of promoting the fat digestion and absorption of freshwater fish, improving liver function and preventing the occurrence of fatty liver disease in the animals. It is believed that rapeseed oil phospholipids can promote the digestion and absorption of fat in freshwater fish and improve the health of liver. The experiment showed that the maximum fatness value of the test group of Grouper bream with 7% rapeseed oil phospholipids was 3.36 (2.66 in the control group), and the minimum proportion of body weight accounted for by visceral fat was 3.62 (4.42 in the control group), and the specific liver weight index was 1.49 (1.72 in the control group), and the liver color and luster also indicated that the liver health was better than that of the control group.
4, biotin
Also known as vitamin B4, or vitamin H, is the intermediate metabolic process plays a catalytic, carboxylation role in a variety of enzymes coenzyme. Biotin is necessary for the normal synthesis of long-chain unsaturated fatty acids and fatty acid metabolism. Animals with chronic deficiencies of biotin in their feed may induce fatty liver disease. Fish plant-based feed ingredients contain biotin to varying degrees, in the process of making bait, biotin is often subject to mechanical processing of high temperature, feed mold, peroxide content of linoleic acid and other factors such as destruction; biotin and amino acids, B vitamins will increase the body's biotin requirements. Reduced levels of B vitamins, vitamin C, folic acid and inositol in fish feeds also increase the body's need for biotin. For this reason, the addition of biotin to the feed is necessary to prevent the development of fatty liver disease in fish.
5, add minerals
With the feed, in addition to the balance between amino acids, add vitamin B, vitamin C, vitamin E, choline chloride, but also need to add calcium, phosphorus, iron, potassium, copper and other elements, the amount of additions is generally 2% -3%.