Low-Density Polyethylene Microplastics in the Rumen: Implications for Rumen Fermentation Dynamics and Utilization of Concentrate Feed

Microplastics are becoming an increasing environmental concern in farm animals. This study presents the first in vitro investigation of the effects of low-density polyethylene microplastic contamination on rumen fermentation dynamics and feed utilization in a simulated ruminal digestive system. Concentrate feed was incubated in buffered rumen fluid collected from lambs, supplemented with low-density polyethylene microplastics and compared to the concentrate incubated in the buffered rumen fluid without microplastic addition. The results indicated that low-density polyethylene microplastics reduced the ability of the lamb rumen to ferment feed, which led to a reduction in metabolizable energy of the concentrate feed. Additionally, this contaminant decreased the number of rumen protozoa and the ammonia levels. These findings underscore the potential risks posed by low-density polyethylene microplastics in ruminant nutrition.