Effect of tamarind seed husk supplementation on ruminal methanogenesis, methanogens diversity and fermentation characteristics

Abstract

Tamarind seed husk, an agricultural waste, was evaluated both in vitro & in vivo as a methane-ameliorating agent. Basal diets for in vitro study were formulated using finger millet straw and concentrate in 70:30 proportions, and tamarind seed husk was included as part of the concentrate with equal (w/w) replacement of wheat bran to achieve 2.5 (T1), 5.0 (T2) and 10.0% (T3) levels. Based on the in vitro results, two levels (2.5%, T1 and 5.0%, T2) of tamarind seed husk were selected for the in vivo study in male cattle to investigate the effect on enteric methane emission. Fifteen crossbred cattle divided into three groups were assigned to the following diets: control (T0, no husk), test group 1 (T1, 2.5% husk) and test group 2 (T2, 5.0% husk). The in vivo study showed a decrease of about 17% in enteric methane emission with a higher level (5%) of tamarind seed husk supplementation. The in vivo study demonstrated a non-adverse impact of supplementation on dry matter intake and digestibility, while rumen methanogens notably decreased at 5% inclusion level. It may be concluded that tamarind seed husk supplementation achieved significant methane reduction via direct inhibition of rumen methanogens without affecting fibre degradability.