Rumen-protected gambir catechins encapsulated using CaO-PFAD: Their effects on rumen fermentation, nutrient digestibility, and methane production in vitro

The objective of this study was to evaluate the impact of rumen-protected gambir catechins encapsulated using calcium oxide (CaO) and palm fatty acid distillate (PFAD) on rumen fermentation profiles, microbial activity, nutrient digestibility, and methane production in vitro. A randomised block design was used, consisting of four treatments and five replicates. The treatments were assigned based on different levels of gambir catechin-CaO-PFAD encapsulate supplementation, namely 0% (A), 5% (B), 10% (C), and 15% (D) in the diet. The results indicated that the treatments significantly affected NH₃ concentration, partial VFA profiles, methane production, microbial protein synthesis, degradation, and nutrient digestibility (P < 0.05), but no significant treatment effects were detected for total VFA, pH, or microbial biomass (P > 0.05). Treatment C produced the highest concentrations of propionate, microbial protein synthesis, degradation, and nutrient digestibility, while reducing methane production and the acetate to propionate ratio. The Cao-PFAD-encapsulated gambir catechin supplementation improved rumen fermentation efficiency, as indicated by increased propionate concentration, microbial protein synthesis, nutrient digestibility, and reduced methane production. Thus, gambir catechin-CaO-PFAD encapsulates could be used as a functional feed supplement to improve nutrient utilisation and mitigate enteric methane emissions in ruminant livestock.