Evaluation of sources of variation on in vitro fermentation kinetics of feedstuffs in a gas production system

Abstract

The aim of this study was to evaluate the effect of different sources of variation in gas production technique on the in vitro gas production kinetics of feedstuffs. Triplicates of commercial concentrate, grass silage, grass hay and grass pasture were incubated in three experiments: experiment 1 assessed two agitation methods; experiment 2 evaluated different rumen inocula (pooled or different donor cows for each incubation run); and experiment 3 used Goering-Van Soest or Mould buffers for media preparation. Gas production data were fitted into the Michaelis-Menten model and then subjected to analysis of variance. Gas production (GP) at 48 h and asymptote gas production (A) were lower when bottles were continuously under horizontal movement. Time to produce half and 75% of A, and A were affected by rumen inocula, while buffer type affected time to produce half and 25% of A and GP. No interactions between substrates and sources of variation were observed, suggesting that the effects of substrates on GP parameters were not modified. It is concluded that comparison of numerical data from in vitro experiments that follow different protocols must be done carefully. However, the ranking of different substrates is more robust and less affected by the sources of variation.

Rumen In Vitro Fermentation and In Situ Degradation Kinetics of Winter Forage Brassicas Crops

“…This is because in vitro gas production rates take into account the gas produced from the soluble fraction, whereas the in situ degradation rate comes only from the insoluble but potentially degradable fraction. Nevertheless, C and MDR values of both swedes and kales (0.14 and 0.15, respectively) demonstrated faster fermentation compared to other typical feedstuffs used for ruminant feeding during winter, such as concentrate (0.11 h −1 for both c and MDR), hay (0.03 and 0.05 h −1 for c and MDR), silage (0.07 and 0.08 h −1 for c and MDR) and pasture (0.09 and 0.10 h −1 for c and MDR) [40].…”

Dose–Response Effects of 3-Nitrooxypropanol Combined with Low- and High-Concentrate Feed Proportions in the Dairy Cow Ration on Fermentation Parameters in a Rumen Simulation Technique

“…This would become even more important during the course of the incubation with regard to inactivating the MCR activity arising time-delayed from slow fermentable fibre fractions in the LC diets. Thus, rates of fermentation of NDF are significantly lower as compared to that of rapidly fermentable NFC [27]. However, the CFP × dose interaction was not significant.…”

Comparative Analysis of Wheat Hay and Silage in Methane Production, Fermentation Characteristics and Microbiota Using In Vitro Rumen Cultures

“…Moreover, the higher culture pH in the DWH7 group than in the MWS15 may be a result of the numerically higher ammonia concentration in the DWH7 group than in the MWS15 group [28]. The gas production in vitro is a valuable index that describes the fermentability of ruminant feedstuffs and estimates DM degradation [29,30]. The greater gas production in the wheat harvested at 15:00 (MWH15, MWS15, DWH15, DWS15) may because that the enzyme activity evaluated or some harmful bacteria were killed through the strong sunshine at noon, thereby increasing the digestibility of OM in the rumen fermentation.…”