The good properties of polyphenols in animal feed

By Monika Korzekwa, product manager, 
Dr Eckel, Germany

Product safety, sustainability and animal welfare are some of the most discussed topics in modern animal production. A steadily growing population and finite resources require the improvement of efficiency in feed and food production to satisfy demand. While intensive animal husbandry is one way to save resources per produced product, high performing animals are prone to diseases often caused by oxidative stress. Oxidants such as Reactive Oxygen Species (ROS) can induce physiological imbalances that may directly lead to inflammatory processes and subsequently to increased energy expenditure. Since inflammation of the intestine not only impairs function and integrity of the gut but also affects growth performance, dietary strategies to inhibit the inflammatory process in the small intestine are in great demand.

Cause of inflammation

Inflammation is a reaction to damage of animal tissues caused by various stimuli. Those stimuli can be physical (e.g. injuries, heat and radiation), chemical (e.g. acids and toxins) and biological (e.g. bacteria, fungi and viruses). The inflammatory process is mainly caused by the transcription factor nuclear factor kappa B (NF-κB). After stimulation by various inducers, for instance reactive oxygen species (ROS), NF-κB activates the expression of genes encoding pro-inflammatory proteins or enzymes involved in the inflammatory process.
The inflammatory mediators contribute to the disruption of the epithelial barrier and favour the activity of other immune cells which enhance the inflammation of the intestine. This is related to an increased energy requirement and can result in a considerable decrease of both zootechnical performance and feed utilisation of livestock.

Polyphenols give protection

More than 4,000 natural polyphenols such as oligomeric proanthocyanidines and flavonoids were described and there is growing awareness of their vast antioxidant potential in animal nutrition. Polyphenols are common components of fruit, legume seeds, chocolate, fruit juices and wine. However, these substances differ considerably in their antioxidant and anti- inflammatory capacity, due to their various polyphenol compositions.
There is evidence from numerous studies in humans and animals that dietary polyphenols, especially some of the group of flavonoid are able to reduce inflammation by modulating the activities of NF-κB. However, the potential anti-inflammatory effects of polyphenols have scarcely been investigated in farm animals so far. Special products of wine/grape juice processing provide an abundant source of flavonoid compounds. Flavonoids from grapes have a high content of resveratrol, anthocyanides, proanthocyanidines, flavonols and phenolic acids. In the production process, selected high quality grapes are separated from the stems and in a further step the grapes are milled.
The milled grapes are then pressed to produce grape pomace and juice. The grape pomace is then dried. In several studies Gessner et al. (2013) observed that these flavonoid-rich products* cause anti-inflammatory effects both in vitro and in vivo (Figure 1).

Better gut health

A large number of studies have been performed regarding different effects of polyphenols. Gessner et al. (2013) observed a significantly improved feed conversion ratio (Table 1) and similar to Sehm et al. (2006) an increased villus height: crypt depth ration in the duodenum. This is in agreement with a broiler study of Viveros et al. (2010) who observed an increased villus height in the small intestine by feeding polyphenol-rich products of wine/grape juice processing.
It is assumed that an increased villus height leads to an improvement of digestive and absorptive functions of the intestine as a result of increased absorptive surface, expression of brush border enzymes and nutrient transport systems (Caspary, 1992).

Conclusions

Polyphenol-rich plant extracts such as special products of wine/grape juice processing are useful for the prevention and inhibition of inflammatory processes in the intestine of livestock and therefore valuable in order to improve both animal health and performance. They are profitable for all animal species in each age group. Due to the improved feed conversion ratios and better health, polyphenols* can save production costs for farmers. Furthermore it is consumer friendly, since there is no carry-over-effect into animal products like milk, eggs or meat.
*Anta®Ox, Dr. Eckel GmbH, Germany. References are available on request.

Article featured in AllAboutFeed 22.7 2014