Four, ruminal fistulated buffaloes, 4 years old with initial body weight (BW) of 321±20 kg, were randomly assigned to receive four dietary treatments according to a 4×4 Latin square design. The dietary treatments were based on different levels of ELM supplementation at 0, 40, 80, and 120 g/hd/d, respectively. Concentrate was fed daily at 0.3% BW and rice straw was offered ad libitum. The experiment was conducted for four periods and each lasted for 21 days. During the first 14 days, all animals were fed respective diets; whereas during the last 7 days, animals were moved to metabolism crates for total urine and fecal collection as well as rumen fluid and blood sampling.