The effect of level of dietary fish oil inclusion on intake and methane emissions of beef steers

Abstract

Irish livestock account for 0.55 million tonnes of methane (CH4) annually from enteric fermentation and manure management (EPA, 2006). However, recent studies have shown the potential to reduce ruminal methanogenesis through strategic dietary supplementation with polyunsaturated fatty acids (PUFA; Jordan et al. 2006). This is likely to be mediated, in part, through the unsaturated double bonds of PUFA acting as sinks for free hydrogen during ruminal biohydrogenation. Fish oil is acknowledged as the richest natural source of long chain n-3 PUFA such as eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids (Ruxton et al., 2004). Despite this, there is little published information on the effect of dietary fish oil supplementation on in vivo ruminal methanogenesis in cattle. The aim of this study was to assess the effect of a novel concentrated n-3 PUFA fish oil, on the intake and CH4 emissions of beef steers.