Affiliation:
1. Biotechnical Faculty Department of Animal Science University of Ljubljana Domžale Slovenia
Abstract
AbstractBackgroundAccurate dosing of feed additives is often required to evaluate their effects on rumen fermentation. This can be done using soluble but nonfermentable hydroxypropyl methylcellulose (HPMC) hard capsules.ObjectivesThe aim of the study was to evaluate the effect of HPMC hard capsules on the extent and rate of in vitro gas production in eleven feeds.MethodsSix high‐fibre feeds and five concentrates, were weighed into syringes either directly or into HPMC capsules and incubated anaerobically in 30 mL buffered rumen fluid at 39°C. Data obtained from gas production measurements were fitted using the Gompertz model to obtain kinetic parameters for gas production.ResultsHPMC hard capsules had no effect on the gas production of the blank sample and concentrate feeds. In contrast, high‐fibre feeds weighed in HPMC showed a significant decrease (p < 0.05) in total gas production and gas produced within 24 h of incubation.ConclusionsThe use of HPMC hard capsules was found to be inappropriate for determining gas production kinetics because fermentation subsides at a certain point when peak fermentation is reached (at TMFR), resulting in a decrease in both total potential gas production and gas production within 24 h of incubation. This is particularly evident when high‐fibre feeds are incubated.