Tannin in Ruminant Nutrition: Review

Abstract

Tannins are polyphenols characterized by different molecular weights that plants are able to synthetize during their secondary metabolism. Macromolecules (proteins, structural carbohydrates and starch) can link tannins and their digestion can decrease. Tannins can be classified into two groups: hydrolysable tannins and condensed tannins. Tannins are polyphenols, which can directly or indirectly affect intake and digestion. Their ability to bind molecules and form complexes depends on the structure of polyphenols and on the macromolecule involved. Tannins have long been known to be an “anti-nutritional agent” in monogastric and poultry animals. Using good tannins’ proper application protocols helped the researchers observe positive effects on the intestinal microbial ecosystem, gut health, and animal production. Plant tannins are used as an alternative to in-feed antibiotics, and many factors have been described by researchers which contribute to the variability in their efficiencies. The objective of this study was to review the literature about tannins, their effects and use in ruminant nutrition.

Compared to antibiotic, feeding peony byproducts can improve growth performance, rumen fermentation, slaughter parameters, and meat quality of lambs

“…Many studies have demonstrated that active substances, including monoterpenoid glycosides, paeonols, flavonoids, phenols, and tannins, can improve gastrointestinal health in animals (Besharati et al, 2022; Kang et al, 2022; Pei et al, 2020; Yu et al, 2019). Meanwhile, PR had better effects on rumen fermentation, most likely due to the presence of paeonols in the PR, whereas PSL and PSM have limited paeonols and there is increasing recognition that they have a vital role in gastrointestinal health (Kang et al, 2022).…”

“…Herbal byproducts (tea residue) altered rumen fatty acid composition and rumen microbiota and improved muscle metabolism in steers (Li et al, 2022). Furthermore, tannins affect meat fatty acid profile through rumen level modulating lipid metabolism (Besharati et al, 2022). More importantly, fatty acid metabolism is closely related to amino acid metabolism (Wallace et al, 2018); therefore, changes in amino acids in lamb meat in our studies were reasonable, although mechanisms are not clear.…”

“…Those results were attributed to some bioactive substances having dose‐dependent effects (Zhong et al, 2015), with high concentrations of flavonoids, tannins, or phenols in peony byproducts adversely affecting intestinal health. For example, high concentrations of tannins affected morphology and proteolytic activity of rumen microorganisms (Besharati et al, 2022; Hoste et al, 2006).…”

“…Many studies have demonstrated that active substances, including monoterpenoid glycosides, paeonols, flavonoids, phenols, and tannins, can improve gastrointestinal health in animals (Besharati et al, 2022;Kang et al, 2022;Pei et al, 2020;Yu et al, 2019).…”

“…However, the high level of PR had a higher live weight but a smaller heart weight. This may be due to the fact that the active components of peony are mainly concentrated in its roots, and these active components all have an optimal dosage range, and it is not that the higher the content of these active components is better, such like tannin (Besharati et al, 2022) and paeonols (Adki et al, 2020), which is rich in PR.…”