Effects of supplemental lauric acid-rich oils in high-grain diet on in vitro rumen fermentation

A series of in vitro studies were performed to evaluate the effects of lauric acid (LA)-rich oils on rumen fermentation with a high-grain diet. Soy oil (SO) and palm oil (PO) as long-chain fatty acid triglycerides, palm kernel oil (PKO), coconut oil (CO), powdered coconut oil (pCO) and coconut oil calcium salt (COCa) as medium-chain LA-rich oils were used as tested additives. Rumen fluid from steers fed high-grain diet was incubated with ground corn with or without oil supplementation (2.0 g/L) for 6 h at 39 degrees C to monitor rumen products. Methane production decreased, while hydrogen production increased on LA-rich oils except COCa. All the LA-rich oils increased total volatile fatty acids (VFA) production and molar proportion of propionate. Also, amylase activity in culture was higher when these oils were added. The most potent additives, pCO and free LA, were further tested to determine dose-response of rumen fermentation. Powdered coconut oil and LA altered rumen fermentation toward more propionate production by supplementation at 1.2 and 0.3 g/L, respectively. These results suggest that some LA-rich oils and free LA could be used for improving rumen fermentation under high-grain diet feeding conditions.