Mitigating methane production from ruminants; effect of supplementary sulphate and nitrate on methane production in an in vitro incubation using molasses and cassava leaf meal as substrate

Le Thuy Binh Phuong, Duong Nguyen Khang, T R Preston* and R A Leng**

Nong Lam University, Viet Nam
binhphuongty27@yahoo.com
*Finca Ecologica, TOSOLY, UTA (Colombia)

AA#48, Socorro, Santander, Colombia
**University of New England, Armidale NSW, Australia

Abstract

The research including two in vitro experiment with these two objectives is to compared effect of three nitrate salts with urea (experiment 1) and evaluate supplementary three levels of sulfur (0, 0.4 and 0.8 % of DM diet) with urea replacement by nitrate as NPN (experiment 2) on methane production of rumen fluid with molasses and cassava leaf meal as substrate . Four treatments of  experiment in randomized complete design were isonitrogenous levles. The results showed that during 24h incubation, compared to urea treatment, nitrate diminished total gas and about 40% methane. However, there was no difference among nitrate treatments in total gas and methane production

The second experimental designs were allocated according to randomized completely with 6 treatments, 4 replicates and consisted of two factors: 3 levels of sulfur (0, 0.4 and 0.8% of DM diet) and supplementary nitrate or urea as NPN. The results showed that potassium nitrate reduced methane production compared with urea. This effect of nitrate was consistent over successive in all stage of 48h incubation. Increasing supplementary level of sulfur in treatment with molasses as fermentable substrate did not affect on methane production in primary fermentation (24h). However, supplementary sulfur in treatment reduced methane production in secondary fermentation (48h) but there was no difference between 0.4 and 0.8 %S. There were consistent effect of nitrate and tendency for methane to be less with increasing level of sulfur after 48h incubation, with indication that methane is reduced more by sulfur when the NPN is nitrate.

Key word:  Calcium nitrate, climate change, fermentation, gas production, greenhouse gases, urea, substrate