Effect of microplastic on rumen metabolism.

The environmental pollution by microplastics and their additives represents a problem for human health and food safety because they are accumulated in water, soil, and crops and transferred by animal feeding in milk, meat, and eggs. The role of bisphenols and phthalates as endocrine disruptors or carcinogens has been proved. Literature suggests that several bacterial species can metabolize microplastics or their additives. Hence, microbial communities of rumen could interact with microplastics and their additives resulting in a possible alteration of bacterial activities. This study aimed to evaluate the effect of several bisphenols and phthalates on rumen ecology using an in vitro trial. Bisphenols A, AF, F, S, C and monomethyl-, diethyl-, monobutyl-, dimethyl-, monobenzyl-, dioctylphthalates were individually fermented (0.83 mg/mL) using ewe rumen liquor as inoculum. Results showed that bisphenols affect differently microbial fatty acid metabolism compared to phthalates. The C18:0 (p<0.0001) concentration decreased while C18:2 c9c12 (p<0.0001), C18:2 c9t11 (p<0.0001), and C18:3 c9c12c15 (p<0.0001) content increased in fermenters containing bisphenols compared to the others. Monounsaturated fatty acid concentration was significantly affected by bisphenol presence in feeds (p<0.0001). The saturated fatty acid concentration was different between treatments (p<0.0001), with the highest value in the control fermenters and the lowest in the Bisphenol A ones. In conclusion, the additives of plastics interfered with microbial metabolism and the results on fatty acids showed a possible different action on microflora.