Gas box system to measure the effects of low-density polyethylene microplastics on rumen activity

The alarming presence of microplastics in the digestive system of ruminants highlights the urgent need for precise assessment methods to comprehend their effects specifically on rumen function, an integral aspect of overall animal health. This study aimed to validate the applicability of an in vitro gas box system, that mimics the rumen environment, for exploring the effects of introduction of varying levels of low density polyethylene microplastics (ranging from 2 to 200 mg/30 mL of buffered rumen fluid) into the rumen under controlled laboratory conditions. The results successfully demonstrated the effectiveness of this technique in detecting the effects of lowdensity polyethylene microplastics on the dynamic of gas produced by rumen fermentation including asymptotic gas production, the constant gas production rate, the average fermentation rate, the time to the onset of rumen gas production and the time to half maximum gas production. Moreover, this system detected the effects of the low-density polyethylene microplastics on concentration of rumen ammonia nitrogen and the level of rumen protozoa. Lastly, the study highlighted the ability of the gas box system to discriminate not only the presence of low-density polyethylene microplastics, but also its dose-dependent effects across all these parameters.