1. Tannin  characteristics

(1) tannin also known as tannin or tannic acid, moisture absorption is strong, easy to oxidize.

(2) tannin has a strong acerbity, poor palatability.

(3) tannin can combine with protein to precipitate and form insoluble complex by chelating with metal ions.

2. tannin is a natural product of polyphenols widely found in many plants, which has strong biological properties and pharmacological activities.

3. In terms of structure and activity, tannin can be divided into two types: hydrolyzed tannin and condensed tannin.

4. Hydrolysis of tannin

(1) Hydrolyzed tannin is a polyphenol synthesized by polymerizing polyols and sugars via ester bonds with phenolic acid and its derivatives. Its molecular weight is 500-3000. More simple compounds including tannin and tannic acid tannic acid tannin were hydrolyzed under the action of dilute acid, dilute base and tannin hydrolase.Phenolic polyester compounds with D-glucose as the core, such as gallic acid and trihydroxybenzoic acid, are contained in the hydrolyzed tannin, and the ester bond of glucose gallate has a strong antioxidant effect.

(2) It can be extracted from the bark and fruit of gallnut, chestnut, sumac, coattail and hazel.

(3) Hydrolyzed tannin can be used as feed additives in feed, and its hydrolyzed products gallic acid and glucose can improve the growth performance and intestinal health of monogastric animals.

5. Condensation tannin

(1) Condensed tannin is a polymer formed by repeated polymerization of flavanols with a molecular weight of 1000-20000, which can be divided into flavanol monomers and polymers according to the molecular weight.Condensed tannin is a kind of antitrophic factor, which is formed by oxidation dehydration and condensation under the action of acid, alkali or bacteria to form a macromolecule

red brown insoluble in water precipitation, thus reducing the growth performance of monogastric animals and producing antitrophic effect.

(2) It mostly comes from the rhizome of Hyacinth and Hyacinth, the stems and leaves of Hyacinth, the grape skins and seeds.Most of the tannins in herbage and fruit are condensed tannins.

6. tannin product type

(1) Coated with hydrolyzed tannin: 40%, 50% content, no moisture absorption, no oxidation, astringency taste light.

Chinese gallnut hydrolysis tannin : China is mainly for gallnut tannic acid, a large yield.

Chestnut wood hydrolysis tannin: mainly produced in Europe.

(2) Tannin protein: flavorless tannin preparation made with protein by special chemical process

Hydrolysis of tannin

1. Convergence

Hydrolyzed tannins are polyphenols plant extracts, intramolecular hydrophobic key can make the polyphenols to be near surface protein molecules, protein activity center and tannic acid protein was hydrolyzed with multiple sites bond formation and small intestine alkaline hydrolysis intestinal juice will gut release of tannic acid, tannic acid protein decomposition promote vasoconstriction, reduce inflammatory exudation, alleviate the stimulation of intestinal contents, provide a good

environment in the development of digestive tract.In addition, hydrolyzed tannic acid can prolong the retention time of chyme in the small intestine through its effect on intestinal convergence, reduce intestinal overfeed, improve feed utilization rate, reduce fecal water content, promote feed digestion and absorption, reduce diarrhea rate, and improve growth performance.

2. Antibacterial and bacteriostatic effects

Hydrolyzed tannic acid is a polyphenolic substance composed of many "phenolic nuclei". The hydrophobic group of its internal benzene ring can be combined with hydrophobic groups such as benzene ring and hydrocarbon chain in protein molecules to denaturate or solidify proteins, inhibit microbial nitrogen metabolism, and thus inhibit the reproduction of bacteria and fungi.

3. Antioxidant effect

(1) Catophenol hydroxyl contained in the hydrolyzed tannic acid molecule is an excellent hydrogen donor, which can scavenging free radicals and has obvious inhibitory effect on lipid peroxidation. It can inhibit the peroxidation of linoleic acid emulsion and is a kind of natural antioxidant.

(2) It has anti-heat stress effect.

4. Anti-inflammatory effect

The hydrolysis of tannic acid may have an anti-inflammatory effect by affecting phagocytes and blocking inflammatory pathways.Studies have shown that the combination of hydrolyzed tannic acid and intestinal cell wall can form a protective layer, block the binding of bacteria to intestinal receptors, improve intestinal microecological environment and inhibit bacterial infection, improve the area of small intestine absorbing nutrients and the activity of digestive enzymes in small

intestine, and promote the absorption of animal nutrients.

5. Antiviral effect

The hydrolysis of tannic acid can inhibit the synthesis of viral glycoproteins, interfere with the virus adsorption on the host cell membrane, and thus play an antiviral effect.Hydrolyzed tannic acid has strong antiviral ability, which makes it have a good application prospect in medicine.

6. Anti-parasite effect

(1) Hydrolysis of tannic acid has an inhibitory effect on animal gastrointestinal parasites.

(2) The hydrolysis of tannic acid can impede the normal physiological metabolism of the parasite by directly binding to the protein of the parasite, or by regulating the immune response of the host to eliminate the parasite entering the body.

7, deodorant

Tannic acid can coagulate with protein, prevent bad fermentation of protein to produce odor, reduce urine nitrogen, manure nitrogen and ammonia gas, and reduce the breeding of mosquitoes and flies.

Application of hydrolyzed tannin in non-resistant feed

1. Application of hydrolyzed tannic acid products in piglet feed

Most studies have shown that adding 0.7-1.5kg/t of hydrolyzed tannic acid to the diet of weaned piglets can reduce diarrhea, improve production performance, replace antibiotics and reduce the amount of zinc oxide.Sui Hui et al. (2013) added 0.07% 80% tannin to the diet of weaned piglets, which significantly increased daily weight gain, reduced feed to meat ratio and reduced diarrhea rate compared with 0.04% 15% jinomycin and blank control group.Sun Zhanying et al. (2014) found that 0.1% tannic acid was used in the feed of Suckling piglets to replace some acidifying agents, zinc oxide and myxobacteria, which could increase the activities of pepsin,

amylase and lipase, improve the digestibility of crude protein and crude fat, significantly improve the daily weight gain of piglets, and reduce the rate of diarrhea.Xin Suwen et al. (2015) added 1kg chestnut tannic acid to the diet of weaned piglets, and found that it did not affect the performance of piglets, could prevent the rate of diarrhea of piglets, and could completely replace mucin sulfate and zinc bacitracin.An Wenting et al. (2014) substituted 1.5 kg chestnut tannic acid for the same amount of zinc oxide in the diet of piglets and found that the daily weight gain and digestibility of crude fiber, calcium and phosphorus in piglets were significantly increased and the diarrhea rate was reduced.

2. Application of hydrolyzed tannic acid products in growing pig feed

Tannic acid added to the diet of growing and finishing pigs can improve its growth performance, promote digestion and reduce diarrhea.Liu Shudong et al. (2014) added 450 g/ T chestnut tannic acid to growth and finishing pigs and found that the digestibility of energy, crude protein and phosphorus was increased, daily weight gain was significantly increased, and diarrhea rate was reduced.Pang Shukun (2015) used chestnut tannic acid of 450 g/t to replace myxobacterium and aureomycin in

the diet of fattening pigs and found that the diarrhea rate was significantly reduced, the serum creatine kinase activity and malonaldehyde content in pigs were significantly reduced, and the total superoxide dismutase activity was significantly increased.

Adding tannic acid to the diet of growing pigs can also improve the antioxidant capacity of the body and improve the meat quality.Ranucci et al. (2015) added 0.1% chestnut tannic acid and 0.1% oregano oil to growth and finishing pigs and found that the activities of glutathione peroxidase and glutathione reductase in longus dorsi muscle increased, while the degree of lipid peroxidation in meat decreased.For cooked meat samples, the L and H values are lower, while the A values are higher.Sensory evaluation of flesh color, taste, and overall score was higher than that of the control group.

3. Application of hydrolyzed tannic acid in chicken feed

Adding hydrolyzed tannic acid to chicken diet can improve intestinal flora, increase digestive enzyme activity, increase intestinal absorption area, reduce ammonia content in feces, improve production performance and slaughtering performance, and improve meat quality.Hou Haifeng et al. (2016) added 0.15% hydrolyzed tannic acid into the diet of broilers and found that the growth rate and feed reward of broilers were significantly improved, the semi-clean chamber rate was increased, the

abdominal fat rate was reduced, and the muscle pH was reduced.China agricultural university animal sciences in broilers diet adding 300 g/t respectively, 500 g/ton, 750 g/t tannins instead of 8.0 g/t avila toxin (effect) found that when tannins add quantity of 500 g/ton or 750 g/tons can replace 8 PPM avila, and could improve the growth performance of broilers.

The addition of tannic acid to the diet of broiler chickens can also reduce heat stress, improve antioxidant capacity, and improve the fatty acid composition of pectoral muscle.Li Hong et al. (2015) found that the addition of chestnut tannic acid in the diet had no significant effect on the growth performance of broilers at room temperature, but under the condition of high temperature and heat stress, the addition of 0.3% chestnut tannic acid could significantly improve the antioxidant capacity of broilers and alleviate the influence caused by high temperature and heat stress.

The hydrolysis of tannic acid can improve the production performance of livestock and poultry and the anti-oxidation ability of the body. It can replace antibiotics and reduce the amount of zinc oxide.Tannic acid as a natural plant extract, no residue, and has a variety of biological functions, has broad application prospects in animal production.