Mr. HuyenMai: Thank you for your question. Yes you are correct, 75% is the minimum level of tannins found in Silvafeed(R) Nutri P. These are extracted from the Italian Chestnut and Argentine Quebracho trees and combined to produce Nutri There is recent data (Carrasco et al., 2017) presented in St. Louis, Missouri at the Sympoisum on Gut Health in Farm Animals which indicates that a 0.1% level of S ...