The secrets of fermented grape polyphenols

Antioxidants are important means to prevent the harmful effects of oxidative stress on the animal’s growth performances, immunity and health. In the last few years, antioxidants have received an increasing attention because of the possible toxicity of their synthetic kind. Thus, it is important for the producers to find new natural alternatives. The polyphenols derived from plant extracts can represent a solution.

Polyphenols play a key role within the plant and animal kingdom, and provide interesting opportunity in both alimentary and nutraceutical fields.

Polyphenols are little molecules that can be found in plants only and are the active principles of many medicinal herbs.  Their main action is the antioxidant one: they catch and neutralize “oxidizing” substances free radicals that, if produced in excess, have negative effects on the organism and are involved in the harmful effect of many pathologies. The polyphenols can exert a positive effect on the gastrointestinal apparatus by metabolizing (chemically transforming) toxins, reducing their negative action. Moreover, they promote the maintenance of the intestinal microbiota eubiosis, acting as a prebiotic substance, which means that they increase the quantity of healthy bacteria in the intestine, such as the Lactobacillus strains. In a scientific study, it has been demonstrated that rats feeding on red wine polyphenols had predominant bacteria totally different compared to those that did not consume polyphenols: in the latter case rats showed a predominance of Bacteroides, Clostridium and Propionibacterium species, whereas rats on polyphenols-based diet had Bacteroides, Lactobacillus and Bifidobacterium species mostly.  This shows that the intake of polyphenols has a remarkable impact on intestinal bacteria. Researchers are discovering that the relation between polyphenols and intestinal microbiota is a two-way road: the polyphenols change the intestinal bacteria composition, while the intestinal bacteria are responsible for the polyphenols metabolism in their bioactive metabolites.

In nature, the polyphenols can be divided into three classes: flavonoids, non-flavonoids and tannins. These latter, commonly indicated with the term tannic acid, are hydro-soluble polyphenols present in many plant foods. They are the most used in the animal feeding thanks to their ability to decrease the feed consumption, while increasing the growth rate and the feed efficiency.

Their use in feed destined to farm animals is becoming increasingly popular since the animals are particularly exposed to oxidative stress. In order to avoid the formation of free radicals that usually lead to such stress and other disease linked to redox, it is necessary to safely eliminate them through the administration of antioxidant compounds. In the last few years, evidence is emerged that the oxidative stress carries out a key role in the development and perpetuation of inflammations, together with the potentiality of plant polyphenols of counteracting such stress and the subsequent inflammation. Another action that the antioxidants perform is the improvement in the nutritional condition and the food intake thanks to some plant extracts that improve the feed flavor and palatability, subsequently improving the production performances. The higher palatability stimulation results in an increased food consumption, that means weight gain. As regards the vegetable extracts rich in polyphenols, it has been shown that an increase in the digestive secretion (such as saliva and digestive enzymes) increase the animals’ growth, by improving the absorption and use of nutrients. Studies in ruminants have mainly focused on the induction of changes in the rumen microbial populations and on the subsequent effects on the ruminal fermentation.

In a French viticultural region, Languedoc, some farmers have started feeding their animals with their local red wine to improve the taste of meat, making it softer and tastier. Two Angus cows and one Camargue have been fed with a mixture of grape waste, barley and hay accompanied by the administration of two liters of wine. Farmers claimed that the better taste of meat not only was it a result of the change in the cows’ diet, but also a result of the improved animals’ health determined by the wine, which can develop beneficial effects.

In 2010, a Canadian farmer, Janice Ravndahl, carried out a similar experiment, introducing red wine in his animals’ diet 90 days before the slaughter. Moreover, in Australia, a group of scientists has found a relation between feeding cows with pomace and the increase in milk production. While, for the chef Gordon Ramsay, it is customary to supplement his pigs’ diet with beer to obtain better meat.

According to Jean-Charles Tastavy, founder of Vinbovin, cows can consume up to one liter and a half of wine per day, the human equivalent of two or three glasses. A systematic introduction of wine in the cows’ diet will inevitably affect on prices, driving them up to 100 euros per kilo for the finest cuts of meat.

In other words, we are dealing with special meat destined to high-end restaurants. Some starred chefs – like Laurent Pourcel – are already very intrigued by this version, so much so that they have become the best clients of the Languedoc beef meat production.

Akron Srl R&D group – on the basis of the extensive scientific research on polyphenols and their activity – has conceived ad hoc products to ensure a higher energy intake and an increase in the animal’s appetite. In order to guarantee a high-quality polyphenols supply, we have developed an innovative production method based on the fermentation of plant extracts rich in nutrients, such as the products and byproducts of the fruit transformation (grape). This process, indeed, allows the polyphenols to become more bioavailable and – subsequently – more easily absorbable by the animal. Meanwhile, in terms of nutrition, part of the glycerol added through our fermentation is used from the rumen bacteria for the AGV production and the other part is absorbed by the rumen wall and transported through the liver portal vein, where it is rapidly employed in the glucose synthesis. By reason of this property, the glycerol is used to prevent ketosis in cows and to maintain the milk production stable during the first phase of lactation. In beef cattle, the glycerol represents a valid alternative to energy food, allowing also a decrease in the diet total starch with positive repercussions on the rumen acidosis.

Such compounds, associated to energy sources – such as molasses and glycerol – allow the animal to receive the proper energy amount, also re-balancing the gastrointestinal microflora.



“Effect of raw and fermented grape seed on growth performance, antioxidant capacity, and cecal microflora in broiler chickens”
E. Gungor, A. Altop, G. Erener 2021

“Dietary Polyphenol Supplementation in Food Producing Animals: Effects on the Quality of Derived Products” by Valentina Serra, Giancarlo Salvatori, Grazia Pastorelli, 2021
“Antioxidant activity and total polyphenol content of selected herbal medicinal products used in Poland “ Aleksandra Duda-Chodak*, Tomasz Tarko, Magdalena Rus