Supplementation of increasing amounts of linoleic acid to Leymus chinensis decreases methane production and improves fatty acid composition in vitro

Abstract

The effects of linoleic acid (LA) supplementation on in vitro dry matter disappearance (DMD), gas production, methane and hydrogen gas production, ruminal fermentation characteristics, and fatty acid (FA) profiles in fermentation fluid were investigated in vitro. Rumen fluid was collected from four ruminally cannulated goats, diluted with incubation buffer, and then incubated with 500 mg Leymus chinensis meal supplemented with different amounts of LA (0, 20, 40, and 60 mg for the control, LA20, LA40, and LA60 groups, respectively). In vitro rumen incubation was anaerobically carried out in 130‐mL sealed fermentation bottles at 39°C for 48 h, and samples were collected at three time points (12, 24, and 48 h) for analysis. Supplementation of LA reduced DMD (P<0.05), the cumulative gas production, theoretical maximal gas production and methane production (P<0.05), whilst increased the hydrogen gas production. In addition, LA addition to substrate had no negative effects on ruminal fermentation parameters (pH, NH3, and VFA). The concentration of total polyunsaturated fatty acid (PUFA) and conjugated linoleic acid (CLA) were higher for LA groups than for control during the whole incubation process. These results indicate that LA supplementation in substrate reduces gas and methane production, and increases the amounts of some beneficial fatty acids in fermentation liquid in vitro.Practical applications: Achieving reduction of the production of methane and improving the composition of fatty acids in ruminant products.Information about H2 concentrations in the rumen of ruminents is scarce. This study investigated the effects of increasing amounts of linoleic acid on CH4 and H2 production when Leymus chinensis was fermented as a substrate in vitro. Supplementing different doses of LA to Leymus chinensis decreased the GP and suppressed CH4 emissions in vitro.