Yucca, commonly known as pineapple, is a genus of yucca in the agave family. Yucca extract is made of yucca, extracted and concentrated by alcohol solvent, and then extracted with water and n-butanol to remove impurities. The n-butanol phase is evaporated to dryness and the ether insoluble matter obtained by refluxing with ether has been used as feed. Additives are used in livestock production. At present, there are two main forms of products on the market: liquid and solid powder. Among them, the liquid yucca extract is a kind of pressed and concentrated yucca juice without any carrier; the solid powder is also divided into two types. One is to directly dry and grind the yucca to make a powder product, without a carrier, containing all the active ingredients of the yucca.
Main active ingredient
Many biological functions of yucca extract are related to its active components, and its main active components include: steroid saponins, polysaccharides, resveratrol, and phoenix orchid polyphenols.
1. Steroid saponins
Steroidal saponins are the most important active components of yucca extract and the most well-studied component. Saponin contains a lipophilic group called sapogenin, and one or more hydrophilic sugar branched chains. It is a natural surfactant or emulsifier, which is conducive to the emulsification of oil and promotes the digestion of monoglycerides. absorption, thereby improving the utilization rate of oil. The hydrophobic part of saponin is linked with the hydrophobic group of cholesterol in the form of micelle superposition in mucosal cells to form a complex to affect the permeability of intestinal cells. In a similar fashion, saponins also have antiprotozoal activity, disrupting the integrity of the protozoan cell membrane by binding to cholesterol at the protozoan cell membrane, resulting in cell lysis.
2. Polysaccharides
Polysaccharides, especially functional oligosaccharides formed by the connection of multiple monosaccharides through glycosidic bonds, are an important active ingredient in yucca extracts. They are not digested by the digestive enzymes secreted by animals themselves and enter the back of the intestine. As a chemical prebiotic, it promotes the growth and reproduction of beneficial bacteria, and can effectively inhibit the proliferation of pathogenic bacteria, maintain the stable structure of the intestinal microflora, and promote intestinal health. In addition, as a nutrient, polysaccharides can be decomposed and utilized by intestinal probiotics such as Lactobacillus and Bifidobacterium, and can also be combined with intestinal ammonia molecules, which can be fully utilized as a nitrogen source for intestinal microbial fermentation, and at the same time effectively regulate The acid-base balance of the gut increases the activity of digestive enzymes and improves the utilization of nutrients such as proteins, vitamins and minerals.
3. Polyphenols
Yucca contains two unique polyphenols, resveratrol and fenugreek polyphenol, which have strong binding ability to amino groups. Therefore, it is speculated that these two polyphenols in Yucca extract may also have the ability to reduce ammonia gas. In addition, the anti-infective effect of resveratrol is remarkable. As a signaling molecule, nitric oxide (NO) plays an important role in physiological functions such as immune regulation and neurotransmission, but excessive NO is cytotoxic and accompanied by inflammation. Marzocco and other studies have shown that yucca polyphenols can inhibit the expression of nitrogen oxygenase (iNOS). NF-κB is a transcription factor that regulates the expression of iNOS gene. Therefore, yucca polyphenols exert a strong anti-infective effect by inhibiting the activity of NF-κB.
main physiological function
1. Reduce ammonia emissions
Ammonia accounts for a large proportion of the odorous gas produced by animal manure and urine in farms. It and highly toxic hydrogen sulfide become the main odor indicator gas in farms. The production of ammonia in feces is mainly due to the excretion of undigested nutrients (especially sulfur-containing amino acids) with the feces, which are fermented by microorganisms to produce a large amount of ammonia and hydrogen sulfide; while the production of ammonia in urine is due to the action of urease, Promote the escape of ammonia gas from urea in large quantities. Urea produced by protein and amino acid metabolism in the intestine is decomposed under the action of urease and ammonia gas is also produced. These intestinal ammonia can damage the mucosal epithelial tissue, affect the physiological metabolism of mucosal cells, destroy the normal intestinal flora composition, break the intestinal acid-base balance, reduce the activity of intestinal digestive enzymes, and ultimately affect the digestion and absorption of feed.
At present, a large number of studies have reported that the active ingredients in yucca extract can reduce the production of ammonia in the feces and urine, and improve the utilization rate of nitrogen in the feed. Its mechanism of action is still inconclusive, and the possible mechanisms are as follows: Yucca extract can reduce the production of ammonia by inhibiting the activity of urease. Numerous studies have reported that yucca extract is a urease inhibitor. Tang Yanjun et al. through two in vitro simulation tests, the results show that Yucca extract has obvious inhibitory effect on urease activity.
Yucca extract has the ability to directly bind ammonia. Buggle et al. reported that macromolecules and sequence molecules in yucca extracts have the ability to adsorb ammonia gas. The polyphenols and ammonia molecules in the composition also have strong binding ability, reducing the emission of ammonia gas. Yucca extract can promote microorganisms to use ammonia in the intestine to form microbial protein, and the nitrogen compounds formed by the combination of polysaccharides and ammonia can also be fully utilized by intestinal microorganisms, thereby reducing the mass concentration of ammonia and improving the utilization rate of nitrogen in the feed. Yucca extract can also reduce the amount of ammonia emitted into the atmosphere by preventing the nitrification of nitrogen in feces and urine, so that nitrogen exists in the form of inorganic substances.
2. Regulate the intestinal microenvironment
The intestinal tract is a very complex environment. Nutrients, physicochemical environment and microbial flora are all in a dynamic balance process to ensure efficient digestion and absorption of nutrients. Once the balance is disturbed, animals can experience various digestive problems. Ammonia is a weak alkaline gas and an important factor affecting the physical and chemical balance of the intestine. Yucca extract reduces the content of ammonia in the intestinal tract, maintains the acid-base balance of the intestinal tract, provides suitable pH conditions for the highest activity of digestive enzymes, and promotes the digestion and absorption of nutrients.
The saponins in the Yucca extract can change the structure of the intestinal villi and the thickness of the mucosa, increase the absorption area of nutrients, and also combine with the cholesterol on the intestinal epithelial cell membrane to form a complex, remove it, and increase the permeability of the intestinal mucosal cells. , reducing the membrane surface tension. Saponins can also combine with compounds similar in structure to cholesterol on the surface of bacteria, increasing the permeability of bacterial cell walls and cell membranes, increasing the secretion of exogenous enzymes and degrading macromolecules around bacteria, making the absorption of nutrients faster. In addition, yucca saponins affected the phagocytosis of bacteria by protozoa by inhibiting intestinal protozoa, which increased the number of fibrinolytic bacteria in the intestinal tract, which was more conducive to the fermentation and degradation of cellulose in the latter part of the digestive tract.
3. Antibacterial effect
According to Chinese applied pharmacology records: yucca saponins have broad-spectrum antibacterial effects against hemolytic Staphylococcus aureus, hemolytic streptococcus, pneumococcus, dysentery bacillus, typhoid bacillus, paratyphoid bacillus, Vibrio cholerae, Escherichia coli , Proteus, Pseudomonas aeruginosa, Bacillus pertussis and its common pathogenic dermatophytes have strong inhibitory properties. Wallance et al. found in the pure culture of carbohydrates on rumen bacteria that the effect of saponins is species-selective, and the effect on Gram-positive bacteria is much greater than that on Gram-negative bacteria, and pointed out that the mass concentration of yucca saponins at 1-10 mg/L can inhibit the Growth of Streptococcus bovis and Shigella.
Bu Changying et al reported that the addition of yucca saponins to the diet significantly reduced the content of Escherichia coli in the cecum of 21-day-old broilers, while the content of Lactobacillus in the cecum showed an increasing trend but the difference was not significant (P>0.05). Yucca extract also has a certain inhibitory effect on fungi. Chen Huajie and others reported that Yucca extract can inhibit the growth of two uricase-producing yeasts, Candida utilis and Pichia pastoris.
4. Improve immune function
Yucca saponins have immunostimulatory activity, can promote the production of antibodies, can stimulate the proliferation of immune cells in vitro, increase the content of CD4+ in the blood, reduce the content of CD8+, and increase the titer of Newcastle disease antibodies. At present, various scholars have put forward many views on the specific mechanism of yucca extract to promote immune system function: Kensil et al reported that saponins can induce the production of cytokines such as insulin and interferon, thereby mediating their immune stimulation response; it may also be related to the Antigen-presenting cells interact to induce the occurrence of an immune response; it has been reported that yucca saponins can enhance the immune response by increasing the uptake of antigens by the intestinal mucosa, and can also combine with antigens to form complexes to avoid the digestion and degradation of antigens .
5. Hypoglycemic, cholesterol-lowering and antioxidant effects
Yucca extract lowers blood sugar and cholesterol levels and has anti-oxidative stress properties. Fidan et al. took diabetic mice as test subjects and found that yucca powder could reduce blood sugar levels in diabetic mice, significantly reduce blood cholesterol and triacylglycerol, and also reduce DNA damage in monocytes. The results of Cigerci et al. showed that the components in yucca can reduce hemoglobin, malondialdehyde content in blood and tissue, and nitric oxide content in tissue, increase glutathione content in blood and tissue, and improve the antioxidant capacity of poisoned mice. The ability to fully protect the body from oxidative damage and its complications caused by nitrite poisoning.
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