Effects of cashew nut shell oil on in vitro methane production and organic matter digestibility of different feed sources

Abstract

The objective of this study was to evaluate the effect of different levels of cashew nut shell oil (CNSO) on methane production and digestibility of various feed sources by using in vitro method. The experimental design was a 3*4 factorial with 3 replications. The first factor was feed source (Brachiaria mutica, Sesbania grandiflora and Operculina turpethum) and the second factor was supplemental levels of CNSO (0, 1, 2, 3 and 4%, DM basis). The substrates (2.5g) were added 200m1 of buffer solution and 50ml of buffalo rumen fluid taken immediately after the animal was killed in the slaughter-house. The incubation was for 96h with easurements of gas and methane production at 6, 12, 24, 48, 72 and 96h. Unfermented solids at 96h were determined by filtering through two layers of cloth and drying at 1050C for 24 h and ashing for 5 hrs to measure the DMD and OMD. The results of this paper showed that the total gas production, CH4 production and concentration after 96h incubation were significantly different (P<0.05) among feed sources and supplemental levels of CNSO with the lowest values at para grass and at 4% supplementation, respectively. It could be concluded that CNSO supplementation could reduce total gas and methane production in in vitro incubation with the higher reduction at 4% of supplemental levels.