Effect of roughage to concentrate ratio and plant oil supplementation on in vitro fermentation end-products

Abstract

An in vitro study was conducted to evaluate effect of roughage to concentrate ratio (R:C) and coconut oil (CO) and wild almond seed oil (WO) supplementation on gas production, volatile fatty acid (VFA) concentration, methane production and dry matter disappearance. Completely randomized design was used for sixteen treatments. Treatments were 4x4 factorial arrangement where four of R:C ratios (100:0, 75:25, 50:50 and 25:75) and four of oil supplementation (un-supplement, 5% CO, 5% WO and 2.5% CO+2.5% WO). The potential extent of gas production was quadratically responded to R:C ratio (p<0.01) while gas production from all fractions of feed were suppressed by oil supplementation (p<0.05). Total VFA production, propionic acid proportion and calculated methane production were linearly increased with concentrate ratio; while oil supplementation decreased (p<0.05) these parameters especially when supplemented with wild almond seed oil. Dry matter disappearance at 24 h of incubation was increased with concentrate quantity but decreased by oil supplementation (p<0.05). It could be concluded that R:C ratio and seed oil remarkably influenced on fermentation end-product and gas production.