Effect of tannin supplementation on nitrogen digestibility and retention in growing pigs

Two levels (0.25% and 0.5%) of water soluble chestnut tannin were added to the diet of growing pigs in a 40 days feeding trial, from the average body weight of 76kg up to about 110kg. As expected, a significant depression of the apparent digestibility of both dietary dry matter and nitrogen was recorded with level 0.5%, but the decrease of retained nitrogen was not statistically significant, due to the higher dietary nitrogen. It is concluded that the present preliminary study showed that a concentration of 250g tannin per 100kg mixed feed does not appreciably influence the animals' performance. The aspect of a possible beneficial effect on the gut microflora deserves further studies.