Effects of tamanu crude oil as feed additive on rumen digestibility, fermentation, methane production through in vitro study

This study aimed to evaluate the effects of tamanu crude oil (TCO) supplementation as a feed additive on ruminal fermentation, digestibility, methane production through an in vitro technique. TCO is rich of plant secondary metabolite and unsaturated fatty acids such as C18:1 and C18:2. A basal diet consisting of Pennisetum purpureum and commercial concentrate (7:3, dry matter basis) was supplemented with TCO at levels of 0, 0.01, 0.05, 0.10 of sample weight dry matter basis. Rumen fluid was obtained from two animal donors and used for in vitro fermentation over 48 hours. In the results, TCO level at 0 and 0.01 were not different on ruminal dry matter and organic matter digestibility, also total volatile fatty acid (VFA). However, TCO level at 0.05 and 0.10 had lower values of these variables than TCO at 0 and 0.01 (p<0.05). Notably, methane production was lower across all supplementation treatments compared to none (p<0.05), with the most favorable balance between ruminal digestibility, fermentation and methane mitigation were observed at 0.01 of TCO application. The findings suggest that TCO at 0.01 may serve as a promising natural feed additive to reduce enteric methane emissions without impairing ruminal function through in vitro study. © 2025, Fundacion CIPAV. All rights reserved.