Ours Continuous Culture Systems
ADVANCED IN VITRO MODELS FOR RUMINANTS NUTRITION STUDIES
To assess the usefulness of isotope ratios, the first step is to test different conditions in controlled in vitro environments that quantify rumen metabolites. Among these, continuous culture systems are the most advanced, as they allow microbial communities to adapt to substrates and treatments over time.
Dual Flow Continuous Culture System (DFCCS)- University of Milan (Italy)
The research unit at UNIMI has recently developed a prototype of a new, modified dual-flow continuous system. This system is designed specifically for the continuous measurement of fermentation gases. The prototype will be used in nutritional studies to evaluate dietary strategies that can mitigate methane emissions. This new system is unique among Italian and European laboratories alike. Specifically, it functions as a dual-flow continuous system in which the outflow is separated into its solid and liquid components. This design produces results that more accurately reflect in vivo observations than ‘traditional’ single-flow continuous fermenters.
Automated Continuous Rumen Incubation system (ACRIS)- Bioeconomy Science Institute (New Zeland)
The ACRIS system consists of two linear arrays of six vessels with an effective volume of 1L situated in a box heated to 39 °C. It has a fully automated intermittent stirring system, an automated feeder for solid substrates, two pumps for buffers or liquid substrates and one for pH control. The combination of a pressure sensor, a gas and a liquid valve achieves the real-time quantification of gas production and the liquid level control. A separate pump and valve setup is used to measure methane and hydrogen using a dedicated gas chromatograph with a maximum resolution of 7 min. The outputs are pH, gas production, methane and hydrogen production. Liquid outflows are collected into a bottle placed in a 4 °C water bath to stop the fermentation.
PRO AND CONS OF IN VITRO SYSTEMS
In vitro methods offer key advantages: controlled conditions, use of the same rumen microbiota across treatments, and the ability to isolate variables like pH and feed intake—factors difficult to control in live animals. However, a major limitation is the absence of short-chain fatty acid absorption, requiring buffering with artificial saliva. This restricts substrate input and dilutes the system compared to in vivo conditions.
