Polystyrene exposure induces lamb gastrointestinal injury, digestive disorders and inflammation, decreasing daily gain, and meat quality.

Microplastics (MPs), recognized as an emerging environmental menace, have been extensively investigated in both marine and terrestrial fauna. This study is comprehensive to investigate how polystyrene (PS) affects ruminant animals. The experimental design comprised 24 individually housed lambs, divided into a CON group (diet without PS) and three PS-exposed (25 µm, 50 µm, 100 µm) groups, each with six lambs, the exposure of PS was 100 mg/day, and the duration of exposure was 60 days. The study yielded noteworthy results: (ⅰ) PS leads to a decrease in average daily gain along with an increase in feed conversion rate. (ⅱ) PS decreases rumen ammonia nitrogen. The rumen microbiota diversity remains consistent. However, the relative abundance of Bacteroidetes and Actinobacteria increased in the PS-exposed groups, while the relative abundance of Coriobacteriales_incertae_Sedis and Prevotellaceae_YAB2003_group decreased. (ⅲ) PS leads to decrease in hemoglobin, thrombocytocrit, and albumin levels in lamb blood, thus triggering oxidative stress accumulation, along with swelling of the kidneys and liver. (ⅳ) PS inflicts severe damage to jejunum, consequently impacting digestion and absorption. (ⅴ) PS reduces meat quality and the nutritional value. In conclusion, PS-exposure inhibited lambs' digestive function, adversely affects blood and organs' health status, reducing average daily gain and negatively influencing meat quality. PS particles of 50-100 µm bring worse damage to lambs. This research aims to fill the knowledge void concerning MPs' influences on ruminant animals, with a specific focus on the meat quality of fattening lambs.

Uptake and distribution of microplastics of different particle sizes in maize (Zea mays) seedling roots.

Microplastics (MPs) pollution may be harmful to terrestrial ecosystems and is receiving increasing attention. A microcosm study on the uptake of MPs in maize (Zea mays) seedling roots exposed to small polystyrene (PS) beads (0.2, 0.5 and 1.0 µm) and large PS beads (2.0 and 5.0 µm) at 50 mg L-1 for 7 d was performed. Additionally, the absorption ability of different parts of the roots was also investigated after 10 d of exposure with 0.2 µm PS beads. The results showed that root and shoot biomass remained unchanged under different particle sizes of PS beads. The small PS beads markedly increased the accumulation and distribution of PS beads in roots more than large ones. Confocal laser scanning micrographs confirmed that strong fluorescence signals from small PS beads (0.2 µm) were seen in all tissues, as compared with the control. Large PS beads (2.0 µm) were mainly distributed in the xylem, and no PS beads were detected in any root tissues when treated with 5.0 µm PS beads. More PS beads were absorbed by the root maturation zone than by the root tip zone. Fluorescence intensity values of PS bead accumulations measured across the tissues further confirmed these results. As seen in scanning electron microscopy images, small PS beads assembled on the cell wall of the xylem, while large PS beads (2.0 µm) were scattered on the cell walls of root xylem. The present study revealed the effects of different PS bead sizes on accumulation and distribution in maize roots, as well as the absorption ability of different positions of the roots. Moreover, fluorescence intensity could be a useful method to evaluate the uptake and distribution of MPs accurately.

Microplastic pollution in soils, plants, and animals: A review of distributions, effects and potential mechanisms.

Increasing production of synthetic plastics and poor management of plastic wastes have dramatically increased the amount of plastics in the environment. In 2014, at the first United Nations Environment Assembly, marine plastic waste pollution was listed as one of the 10 most pressing environmental issues. In addition, there is much plastic waste in terrestrial ecosystems due to substantial residues from agricultural mulching and packing. As a recently recognized pollutant, microplastics (MPs) have attracted significant attention from the public and various governments. Concentrations of MPs in the environment vary among locations, from <100 to >1 × 106 particles per cubic meter. Many studies have addressed the impacts and potential mechanisms of MPs on the environment and organisms. Humans and other organisms can ingest or carry MPs in a variety of passive ways and these MPs can have a range of negative effects on metabolism, function, and health. Additionally, given their large surface area, MPs can sorb various pollutants, including heavy metals and persistent organic pollutants, with serious implications for animals and human wellbeing. However, due to their complexity and a lack of accurate determination methods, the systematic impacts of MP pollution on whole foodwebs are not clearly established. Therefore, this review summarizes current research advances in MP pollution, particularly the impact of MPs on soils, plants, and animals, and proposes potential future research prospects to better characterize MPs.

High-potency white-rot fungal strains and duration of fermentation to optimize corn straw as ruminant feed.

Five white-rot fungi Pleurotus ostreatus, Lentinus edodes, Hericium erinaceus, Pleurotus eryngii and Flammulina filiformis were studied (solid-state incubation and in vitro gas production) to determine lignin degradation and optimal duration of fermentation of corn straw. All fungi significantly decreased lignin, with optimal reductions after 28 d. Although cellulose also decreased, L. edodes and P. eryngii minimized these losses. In intro dry matter digestibility, total volatile fatty acid concentration and total gas production of fermented corn straw decreased (P < 0.001) as fermentation was prolonged, with improved rumen fermentability for all fungal treatments except F. filiformis. Total gas production in L. edodes did not decrease but peaked on day 28, whereas F. filiformis reduced methane emission. In conclusion, fermentation of corn straw with P. eryngii or L. edodes for 28 d degraded lignin and improved nutritional value as ruminant feed.