Poultry producers know a healthy gut is critical for optimal performance. Unfortunately, managing enteric challenges – like coccidiosis and necrotic enteritis – in antibiotic-free production systems is anything but easy. To protect poultry from disease, using feed additives – like tannins – that offer a wide-range of potential benefits for optimal gut health is key.
Tannins are natural phytogenic molecules found in grains, tree wood, gallnuts and fruits. Known for their ability to bind proteins, tannins have traditionally been considered anti-nutritive when used in poultry diets. In reality, tannins represent a highly diverse group of molecules with variable structures and properties. Importantly, tannin source and tannin structure can greatly impact the nutritive or anti-nutritive properties of the tannin.1 Growing research indicates that dietary tannins – when dosed correctly – offer a wide-range of benefits that support optimal gut health and performance of poultry.
Tannins are recognized as highly effective natural antioxidants. Due to their polyphenolic structure, tannins have significant capacity to scavenge free radicals which could otherwise damage intestinal cell membranes leading to oxidative stress and inflammation.
By supporting redox balance, tannins can help to control oxidative stress as well as inflammatory responses in the intestine. For example, application of tannins has been reported to reduce oxidative and inflammatory stress in colon tissue.2 Tannins may also help enhance antioxidant status in serum of muscle tissue as well as improve shelf-life of refrigerated poultry products.
The last time you enjoyed a rich, red wine or ate a bite of 90% dark chocolate, do you recall the acidic, bitter flavor on your tongue? That flavor is due to the astringent, protein-binding property that all tannins possess. Astringency, by definition, describes the ability of a molecule to constrict, or tighten, body cells and other cellular tissues, and this property of tannins can pay major dividends for gut health.
When it comes to intestinal integrity, maintenance of tight junctions between intestinal epithelial cells is critical. Environmental stress, inflammation or enteric pathogens can cause barrier breakdown leading to leaky gut syndrome, malabsorption of nutrients and depressed growth. By helping to tighten junctions between intestinal epithelial cells, tannins can reduce intestinal lesion formation, thereby strengthening intestinal barrier integrity to support performance.
Tannins have been shown to inhibit growth of several poultry pathogens in vitro, including Campylobacter spp.3, Salmonella spp.3 and Clostridium perfringens.4 The antimicrobial, anti-parasitic and anti-viral effects of tannins are likely related to tannin complexation with microbial enzymes and/or metal ions, like iron, that are required for normal pathogen growth and metabolism.5,6
Interestingly, development of bacterial resistance to tannins is expected to be difficult due to the complex structure of tannin molecules. In vivo studies have further shown that feeding tannins can help minimize the negative effects of coccidiosis and necrotic enteritis challenge on poultry performance.7,8
In addition to their antimicrobial properties, tannins may also positively modulate gut microflora and influence mucosal immunity. Recently, broilers fed tannins were found to increase microbial diversity of Ruminococcaceae and Lachnospiraceae bacterial families, both of which are associated with improved intestinal health and feed efficiency of poultry.9 Dietary tannins have also been shown to increase secretory IgA and mucin concentrations within the intestine, indicative of enhanced mucosal immunity.10
Tannins offer multiple benefits to support gut health of poultry. However, producers must remember that using tannins in poultry diets is a balancing act. Choosing the right tannin, at the right level and at the right time is crucial to ensure the benefits of tannin-based feed additives are realized.
As a phytogenic and probiotic combination, VANNIX™ C4 serves as a multi-mode of action gut health solution to help minimize the effects of coccidiosis infection as well as reduce the opportunity for secondary bacterial challenges in poultry. Its tannic acid extract (TAE) – a unique hydrolysable tannin – has been shown to inhibit growth of coccidia parasites and reduce intestinal lesions,8 thereby improving intestinal integrity to support optimal performance of poultry.
For more information on how VANNIX™ C4 can support poultry intestinal health, visit Kemin Animal Nutrition and Health at kemin.com/vannixc4.
1Mueller-Harvey, I. (2006). Unravelling the conundrum of tannins in animal nutrition and health. J. Sci. Food Agric., 86:2010-2037.
2Hamiza, O. O. et al. 2012. Amelioration of 1,2 Dimethylhydrazine (DMH) induced colon oxidative stress, inflammation and tumor promotion response by tannic acid in wistar rats. Asian Pacific J. Cancer Prev. 13:4393-4402.
3Redondo, L. M. et al. 2014. Perspectives in the use of tannins as alternative to antimicrobial growth promoter factors in poultry. Frontiers Microbiol. March(5). doi:10.3389/fmicb.2014.00118.
4Elizondo, A. M. et al. 2010. Effect of tannins on the in vitro growth of Clostridium perfringens. Vet. Microbio. 145:308-314.
5Chung, K. T., et al. 1998. Mechanism of inhibition of tannic acid and related compounds on the growth of intestinal bacteria. Food and Chem. Tox. 36:1053-1060.
6Min, B. R. and S. P. Hart. 2003. Tannins for suppression of internal parasites. J. Anim. Sci. 81(E. Suppl. 2):E102-E109.
7Tosi, G. et al. (2013). Efficacy test of a hydrolysable tannin extract against necrotic enteritis in challenged broiler chickens. Italian Journal of Animal Science, 12:3, DOI: 10.4081/ijas.2013.e62.
8Tonda, R.M. et al. (2018). Effects of tannic acid extract on performance and intestinal health of broiler chickens following coccidiosis vaccination and/or a mixed-species Eimeria challenge. Poult. Sci., 97:3031-3042.
9Carrasco, J.M.D. et al. (2018). Tannins and bacitracin differentially modulate gut microbiota of broiler chickens. BioMed Research International, https://doi.org/10.1155/2018/1879168.
10Karaffova, V. et al. (2019). The influence of Farmatan® and Flimabend® on the mucosal immunity of broiler chicken. Poultry Science, 98:1161-1166.
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