Tannins; Use in Silage and Animal Feeding Applications

Abstract

Aim: This review was made to determine the effects of using tannin on the fermentation quality and animal nutrition as a different alternative to the additives used to prevent the spoilage of silages, which are widely used in today's livestock. Tannins are polyphenolic compounds and are natural compounds with a characteristic odor, acrid taste, and different colors from yellow to white, which can also be found in feeds such as gallnut, oak, chestnut and rapeseed, broad bean, sorghum. Since BC 1500 they have been used in various fields from medicine to food. Apart from its antidiarrheal, antiseptic and anthelmintic effects, its most well-known feature is that it forms compounds with proteins. The high protein/water presence of the feed to be ensiled makes ensiling difficult and affects fermentation negatively. High protein will reduce lactic acid formation in silages due to proteolysis and the desired pH value will not be reached. It is thought that tannins can form compounds with proteins and prevent proteolysis in silages and provide by-pass properties to proteins. Thus, the proteins that pass through the rumen will be digested in the small intestine and their utilization will increase. In addition, methane gas produced by ruminants causes loss of gross energy and contributes to global warming with greenhouse gas. Tannins are considered as an alternative to reduce methane gas and dispose of waste ammonia.
 Conclusion: The use of tannin in silages can facilitate the ensiling of high protein feeds, increase their quality, and meet the nutrient needs of animals better. It can improve the storage conditions of roughage. An innovative feeding method can be provided by reducing the methane production of animals that consume tannin-containing feeds. It can be a natural approach to the disposal of ammonia.