Coconut oil effects on in vitro ruminal fermentation and methanogenesis

Abstract

Methane emission from ruminants can be mitigated with supplementation of medium chain fatty acids (MCFA) such as lauric acid that present in coconut oil. However, the effects of coconut oil supplementation on in vitro rumen fermentation and methane emission have been varied. This study was conducted to examine the effect of dietary coconut oil supplementation on rumen fermentation and methanogenesis by integrating data from various in vitro studies. A linear regression statistical model approach was applied to a total of 14 studies and 38 data points. The response variables integrated were methane emission, fermentation products, nutrient digestibility, and microbial population. The data obtained were analyzed by using IBM SPSS software version 20. The results showed that methane production was decreased significantly (P<0.01) by supplementation of coconut oil. Coconut oil tended to decrease methanogenic archaea, protozoa, total volatile fatty acids and isovalerate proportion (P<0.1). However, the oil supplementation did not significantly affect dry matter digestibility, total gas production, N-ammonia, acetate, isobutyrate, valerate, acetate to propionate ratio, population of rumen bacteria, organic matter digestibility, pH, propionate and butyrate. It can be concluded that coconut oil supplementation is able to mitigate methane emission by modifying microbial population structure and fermentation in the rumen.