单宁酸技术

Despite major structural differences, 饲料级单宁酸hydrolyzable and condensed tannins often produce similar antinutritional effects. The most common effects are diminished weight gains and lowered efficiency of nutrient utilization. The major biochemical basis for these effects appears not to be inhibition of dietary protein digestion but rather a systemic inhibition of the metabolism of digested and absorbed nutrients, particularly protein. In the case of condensed tannins, this inhibition is probably not due to polymeric tannin molecules, which are not absorbed from the digestive tract, but to associated lower MW polyphenols, which are readily absorbed.Despite major structural differences, hydrolyzable and condensed tannins often produce similar antinutritional effects. The most common effects are diminished weight gains and lowered efficiency of nutrient utilization. The major biochemical basis for these effects appears not to be inhibition of dietary protein digestion but rather a systemic inhibition of the metabolism of digested and absorbed nutrients, particularly protein. In the case of condensed tannins, this inhibition is probably not due to polymeric tannin molecules, which are not absorbed from the digestive tract, but to associated lower MW polyphenols, which are readily absorbed.

Because tannins bind to proteins, polysaccharides, enzymes, metal ions, etc., they have long been used as an anti-nutritional factor. In recent years, studies have found that feed grade tannins have strong physiological activities in antibacterial, antiviral, antioxidant and free radical scavenging. The appropriate tannins in the diet have a positive effect on the growth, immunity and reproductive performance of the animals. The article provides a reference for the application of tannins in animal production by reviewing their research progress in the above-mentioned areas.

单宁酸（饲料级单宁酸）是一种天然的多酚类化合物，可降低膳食蛋白的消化率，但也有抗菌作用。本研究在体外和体内研究了不同水平的单宁酸（使用含75%单宁的板栗木提取物）对仔猪生长性能、肠道微生物群和肠壁形态的影响。在体外粪便发酵24 h期间，利用0.75、1.5、1.5、3、6 g/l的单宁酸的利用量显著降低了总产气量和氨气、挥发性脂肪酸的浓度，并增加了肠道菌群和大肠菌群的存活率。当以1.13、2.25和4.5 g/kg的剂量喂养仔猪时，单宁酸显著提高了饲料效率，降低了氨、异丁酸和异戊酸的粪便浓度。空肠中乳酸菌的存活率往往会因单宁的作用而增加，而细菌性粪便数量则不受影响。在2.25和4.5g/kg时，饲喂单宁酸的仔猪回肠囊的深度有下降的趋势。本研究表明，饲用富含单宁酸的木材提取物饲喂断奶仔猪，可提高饲料利用率，减少肠道细菌蛋白分解反应。在体外条件下，单宁酸对肠球菌和大肠菌群的生长促进作用值得进一步研究。

Tannins饲料级单宁酸 are natural polyphenolic compounds that can reduce digestibility of dietary protein but also display antibacterial effects. The present study investigated, in vitro and in vivo, the effect of different levels of tannins (using a chestnut wood extract containing 75% tannins) on growth performance, intestinal microbiota and wall morphology in piglets. During a 24 h in vitro caecal fermentation, the utilisation of tannins at 0.75, 1.5, 3, and 6 g/l significantly reduced total gas production and concentrations of ammonia and volatile fatty acids and increased viable counts of enterococci and coliforms. When fed to piglets at 1.13, 2.25, and 4.5 g/kg, tannins significantly improved feed efficiency and reduced caecal concentrations of ammonia, iso-butyric, and iso-valeric acid. Viable counts of lactobacilli tended to be increased by tannins in the jejunum, while bacterial caecal counts were not affected. Depth of ileal crypts tended to decrease in piglets fed tannins at 2.25 and 4.5 g/kg. The present study showed that feeding weaned piglets with a tannin-rich wood extract 饲用单宁酸can result in improved feed efficiency and reduction of intestinal bacterial proteolytic reactions. The growth-enhancing effect that tannins had on enterococci and coliforms under in vitro conditions deserves further investigation.

结果表明，温度、TA级饲料单宁酸及其相互作用效应显著降低了日增重和采食量。此外，高温下饲料转化率(FCR)显著增加，高温下添加TA并没有改善FCR。温度、TA及其相互作用对饱和脂肪酸和不饱和脂肪酸的影响均不显著（P<0.05）。但在日粮中加入TA后，单宁脂肪酸的单不饱和脂肪酸明显减少。总的来说，TA饲用单宁酸改善了热应激下肉鸡胸肌的脂肪酸谱，与没有接受TA的热应激鸡相比，TA饲用单宁酸改善了肉鸡的脂肪酸谱。由此看来，在高温气候条件下，日粮中补充TA可作为家禽营养的生物抗氧化剂应用。

Results showed that temperature, TA饲料级单宁酸 and their interaction effect significantly decreased body weight gain and feed intake. In addition, feed conversion ratio (FCR) significantly increased under high temperature, and addition of TA under high temperature did not improve the FCR. The effects of temperature, TA and their interaction on the saturated and unsaturated fatty acids were not significant (P<0.05). However, monounsaturated fatty acids significantly reduced by adding TA to the diet. Generally, TA饲用单宁酸 improved the fatty acid profile of breast muscle of broilers under heat stress in comparison to the heat stressed chickens, which did not receive TA. Hence, it seems that dietary TA supplementation can be applied as a biological antioxidant for poultry nutrition in hot climatic conditions.

饲料级单宁酸（单宁酸）是没食子酸分子和葡萄糖的聚合物。在该示例中，有3个没食子酸分子，但通常大约有8个。由于单宁酸的分子结构不同，因此最好谈谈单宁酸（复数）。单宁酸会水解成葡萄糖和没食子酸或鞣花酸单元。单宁酸无味，但味道很涩。纯单宁酸是浅黄色无定形粉末

饲用单宁酸（补充饲料级单宁酸）可能不会影响生长性能、肠道黏度和产仔质量。但是，它可以降低肉鸡FPD的发病率和严重程度。研究人员表示，补充单宁酸饲料级单宁酸的饲料可能会通过减少脚垫皮炎的发生和严重程度，为家禽的足部健康提供一个促进作用。