Effects of graded levels of tannin‐containing tropical tree leaves on in vitro rumen fermentation, total protozoa and methane production

AIMS: This study was carried out to determine the effect of graded levels of tannin‐containing tropical tree leaves, Autocarpus integrifolis, Azardirachta indica and Ficus bengalensis, on the in vitro rumen fermentation pattern, total protozoa and methane suppression in order to establish the optimum dose of these leaves for inclusion in the ruminant diets. METHODS AND RESULTS: The air‐dried and ground samples of Au. integrifolis, Az. indica and Ficus bengalensis were subjected to in vitro incubation using 30 ml buffered rumen fluid at 0, 2·5, 5·0, 10·0, 15·0, 20·0, 25·0 and 30·0% (dry matter refers to moisture‐free basis) of a total mixed ration (TMR: refers to mixture of roughage and concentrate containing cereals and oil cakes) devoid of tannin. The TMR for the experimental incubation was prepared by mixing 40 parts of ground Elusine coracana straw as roughage source with 60 parts of concentrate mixture. The leaves contained an average 130 g kg⁻¹CP with 7·0 MJ of ME kg⁻¹DM. The average neutral detergent fibre (NDF) content was