Effect of ingestion of hydrolysable tannins in Terminalia oblongata on digestion in sheep fed Stylosanthes hamata

Abstract

Effect of hydrolysable tannins in the browse tree Terminalia oblongalu (yellow-wood) on digestion of organic matter, fibre and nitrogen in the stomach and intestines, was studied in sheep fed a basal diet of the tropical legume Stylosanthes hamata (verano). These tannins are toxic to the liver and kidneys, but their effect on digestion is not known. Although two of the four sheep used showed signs of yellow-wood toxicity with an intake of 0.9 g tannin/kg body weight, there were no significant effects on OM, N and CWC digestion of verano in the alimentary tract as a whole. However, yellow-wood appeared to depress OM and CWC digestion in the stomach, but this was compensated for by greater intestinal digestion. The OM digestibility of verano in the whole tract was 0.59 of intake, with two-thirds due to digestion in the stomach. About 0.87 of the total N loss (0.68 of intake) in the gut occurred in the intestines, and microbial N production was 33 g/kg of verano OM digested in the stomach. Therefore intake of non-toxic levels of yellow-wood should not compromise digestion.