Effect of mixture of medium chain fatty acids and unsaturated fatty rich oils on methane production and rumen fermentation in vitro

An experiment was carried out to evaluate effect of mixture of medium chain fatty acid sources with unsaturated fatty acid rich oil supplementation on methane production, dry matter digestibility and other rumen fermentation parameters using in vitro gas production technique. Completely randomized design was used with ten treatments including control. Treatments were supplemented with 1% Coconut oil (CO) + 1% Palmolein oil (PO), 1% CO + 1% Mustard oil (MO), 1% CO + 1% Linseed oil (LO), 1% Lauric acid (LA) + 1% PO, 1% LA + 1% MO, 1% LA + 1% LO, 1% Myristic acid (MA) + 1% PO, 1% MA + 1% MO and 1% MA + 1% LO on dry matter (DM) basis in total mixed ration (TMR) containing 40: 40: 20; concentrate, wheat straw and green maize. Supplementation with CO+LO, LA+PO, LA+MO, LA+LO and MA+LO significantly (P<0.05) decreased methane production compared to control group and the percent reduction was 16.98, 18.87, 21.70, 26.42 and 19.81% respectively. However, methane reduction was accompanied by decreased IVDMD except in case of MA+LO supplementation. Unsaturated fatty acid, especially linolenic acid rich oil i.e. LO blends resulted in significant (P<0.05) decrease in methane production compared with other vegetable oils. Concentration of NH₃-N decreased significantly (P<0.05) in CO+LO, LA+PO and LA+MO supplemented diets. Acetate level was decreased (P<0.05) with all treatments and propionate concentration was increased at the expense of acetate. Acetate to propionate ratio also decreased in all fat supplemented diets except LA+LO. The present study demonstrated that addition of mixture of medium chain fatty acids and unsaturated fatty acid rich oils in diet decreased methane release, and the effect was enhanced with LO blends especially with MA.