A new equipment for continuous measurement of methane production in a batch in vitro rumen system

Abstract

A new rumen batch fermentation system that allows continuous measures of total gas (GP) and methane production (MP) was tested. The fermentation system is composed of glass bottles connected to gas counters (Ritter Apparatebau GmbH & Co. KG) and an infrared gas analyser that measures the methane concentration. The system allows direct and continuous measurement of GP and MP for accurate kinetic studies. The aim of the work was to test the rumen fermentation system and compare the GP and MP kinetics obtained. Barley meal (BM), alfalfa hay (AH), corn silage (CS), and soya bean hulls (SH) were used as substrates in four consecutive fermentation runs. Cumulative volumes of GP and MP and the percentage of methane on total GP were recorded continuously until 48 h and average values at 1 h intervals were fitted with an exponential model with a lag phase reaching a good fit (R2 > 0.992). GP and MP reached the highest plateau levels for SH (1836 and 370 ml, respectively; p < 0.01) and the lowest for AH (1000 and 233 ml, respectively). The remaining substrates showed intermediate values. MP kinetics showed a discrete lag phase (from 0.09 to 1.12 h), whereas it was equal to zero for the total GP (except for SH). The methane concentration in gas flowing increased rapidly at the beginning of fermentation (from 0.35 to 0.95 h−1) and reached a plateau after approximately 8–12 h. In conclusion, the rumen fermentation system evaluated generates methane data comparable to those reported in the literature and allows simple continuous measurement of methane release throughout fermentation.

In vitro aflatoxins recovery after changing buffer or protozoa concentrations in the rumen fermentation fluid

“…The fluid was delivered, within half an hour of it being collected, to the laboratory in airtight glass bottles refluxed with CO 2 and maintained at 39°C. We recently described (Braidot et al, 2022) the in vitro apparatus used in this work. Briefly, it is composed of fermentation glass bottles (100 mm external diameter; 150 mm high and 750 mL total available capacity) closed with an airtight cap in which an electric engine is inserted that rotates an internal mixing paddle.…”