How much do you know about feed-grade tannins?

Tannins have long been regarded as anti-nutritional factors, but numerous studies have revealed that tannin components in feed actually confer several positive effects on animals. Now, with the growing "ban on antibiotics" movement gaining momentum, selecting appropriate alternatives to antibiotics has become an urgent necessity. So, does dietary tannin hold potential as an effective "antibiotic substitute" in animal production—and if so, how feasible is this approach?

Currently, the "ban on antibiotic growth promoters" has become a global trend in livestock production, profoundly impacting the improvement of livestock product quality and safety, boosting the supply of eco-friendly, high-quality animal products, reducing farming costs, enhancing livestock exports, and ultimately supporting the sustainable development of the livestock industry. Tannins, as an alternative to antibiotics, show promising potential for use in animal production. Could you please elaborate on the specific ways tannins can help replace antibiotics in practical animal farming applications?

Natural extract hydrolyzed tannins have been used to treat human diarrhea for centuries, and their application in animal production has nearly six decades of proven experience abroad. In general, hydrolyzed tannins exhibit antibacterial, anti-inflammatory, antioxidant, and antiparasitic properties, effectively inhibiting the majority of both plant- and animal-origin pathogenic microorganisms. When applied in animal farming, they not only enhance overall animal health and improve the safety of animal-derived products but also deliver significant economic benefits.

Tannins have historically been associated with three negative attributes in animal production: palatability issues, feed-blocking effects, and anti-nutritional properties. The palatability problem stems from their astringent taste, which reacts with salivary proteins, leading to a feed-blocking sensation. Condensed tannins—found, for instance, in sorghum—tend to form indigestible complexes with proteins, hindering the proteins' ability to undergo normal metabolic processes. Additionally, condensed tannins can bind to the outer cells of the intestinal lining, reducing the permeability of the intestinal wall. This is precisely how condensed tannins exert their anti-nutritional effects. On the other hand, hydrolysable tannins, when combined with proteins, can be broken down under alkaline conditions into simpler compounds like gallic acid and ellagic acid—low-molecular-weight polyphenols that are readily absorbed by the body. As a result, there’s no evidence that hydrolysable tannins interfere with protein metabolism or synthesis.

Hydrolyzed tannins exhibit broad-spectrum antibacterial, anti-inflammatory, and antiparasitic properties. Containing natural polyphenolic active compounds, hydrolyzed tannins selectively inhibit harmful bacteria while promoting the growth of beneficial microbes, thereby helping to maintain a balanced gut microbiome and strengthening the body’s ability to fend off most pathogenic bacterial threats. Through a competitive exclusion mechanism, these tannins specifically target and suppress the replication of certain bacteria, while also exerting cytotoxic effects that favor the proliferation of lactic acid bacteria and Bifidobacteria—key players in gut health. Additionally, hydrolyzed tannins effectively inhibit the reproduction of several intestinal parasites. As a result, they prove highly effective against bacterial enteritis and diarrhea in piglets.