Toxicological Effects of Polystyrene Microplastics on Growth, Enzymatic Activity, Hematology, and Tissue Integrity in Labeo rohita.

Integrated biomarker responses to dietary polypropylene microplastics in rainbow trout (Oncorhynchus mykiss) under simulated aquaculture conditions

Effects of Aged Polymethylmethacrylate Microplastics on Physiological Biochemistry and Intestinal-Sediment Microbial Communities of Urechis unicinctus (von Drasche, 1881)

Microplastics (MPs) widely distribute in marine environments and generate severe hazards to marine biota, yet little is known regarding the toxic impacts of aged MPs on benthic invertebrates and their surrounding sediment microbiota. This work aimed to fill this research gap by exploring the comprehensive toxicity of aged polymethylmethacrylate microplastics (PMMA-MPs) toward Urechis unicinctus and its sediment habitat. A 21-day laboratory exposure trial was performed with two PMMA-MP treatments: environmentally realistic low concentration (10 μg/L) and extreme high concentration (1000 μg/L). Aged PMMA-MPs accumulated in the body wall and intestine of U. unicinctus, with markedly higher body wall MPs loads in the high-dose group (p < 0.05). High-concentration PMMA-MPs significantly raised intestinal total protein and triggered intense oxidative stress (p < 0.01), and the Integrated Biomarker Response value rose dose-dependently. Sediment microbial β-diversity was obviously reshaped (p < 0.05), with enriched pathogens including Klebsiella and Enterobacteriaceae under high MP exposure, while the worm’s intestinal α-diversity and core microbiome remained stable, showing host adaptability. This study reveals multi-level toxic outcomes of aged PMMA-MPs on benthic worms and their sediment microhabitat, offering fundamental data to evaluate the ecological risks of weathered MPs in marine benthic systems.

Thymol dietary supplementation mitigates microplastic-induced hematological disturbances, oxidative stress, immunosuppression, gene dysregulation, and histopathological alterations in Nile tilapia.

Thymol supplementation against polystyrene microplastics exposure in Nile tilapia may be considered a helpful nutritional additive for lessening the negative impacts of PS-MPs.

Toxicological effects of polypropylene microplastics and co-exposure with arsenic in Drosophila melanogaster

ABSTRACT Microplastics (MPs) are particles smaller than 5 mm that, due to their physicochemical properties, can act as carriers for contaminants such as heavy metals. In this study, we evaluated the toxicological effects of polypropylene microplastics (PP-MPs) and their co-exposure with dimethylarsinic acid (DMA) in the Drosophila melanogaster model. Third-instar larvae were exposed to the following experimental groups: negative control, positive control (0.02% H2O2), cosolvent control (ethanol, 6.94% final concentration), PP-MPs (0.01 g/mL), DMA (0.5 mM), and the co-exposure group (PP-MPs + DMA). Larval-to-adult viability, morphology, tissue damage, and fecundity were assessed. PP-MPs alone did not significantly affect larval-to-adult viability, the incidence of morphological abnormalities, or fecundity; however, evidence of tissue damage was observed. In contrast, co-exposure suggested an antagonistic effect on larval-to-adult viability and tissue damage, while indicating a synergistic effect on fecundity and the incidence of abnormalities. These findings contribute to a better understanding of the biological effects associated with co-exposure to microplastics and arsenic in an in vivo model.

Remedial and toxic effects of lead exposure in Catla catla juveniles: Assessment of growth, carcass, blood profile and tissue metal analysis.

In recent years, waterborne heavy metal (HM) contamination is a major concern in aquaculture systems due to its detrimental effects on fish health. Therefore, the development of effective dietary strategies to alleviate HM-induced toxicity is imperative for ensuring the sustainability of aquaculture production. The present study investigated the efficacy of dietary garlic powder (GP) in mitigating the adverse effects of lead (Pb) on growth indices, hematological parameters, digestive enzyme activity, carcass composition, and tissue health of Catla catla (Thaila). A total of 270 fish were allocated to 18 tanks in triplicate (n=15/tank). Five dietary treatments were formulated containing 0, 5, 10, 15, or 20 g kg-1 GP. The experimental groups were as follows: G1, negative control with no GP supplementation and no Pb exposure; G2, positive control with no GP supplementation and exposure to 1 mg L-1 Pb; and G3-G5, supplemented with 5, 10, or 20 g kg-1 GP, respectively, with exposure to 1 mg L-1 Pb. The experimental duration was sixty days. Results demonstrated that waterborne Pb toxicity had significant (P<0.05) negative impacts on C. catla in terms of growth, body composition, hematology, intestinal enzymes and oxidative stress biomarkers. Pb concentrations increased significantly in the gills, spleen, liver, and kidneys of Pb-exposed fish relative to control. In contrast, GP supplementation significantly (P<0.05) reversed the harmful effects of Pb and improved the growth, blood profile, carcass characteristics, digestive enzyme activities and oxidative status of fish, with the most pronounced effects at 5 g kg-1 diet. In conclusion, the dietary GP incorporation into the diets of C. catla effectively improved fish health and mitigated Pb toxicity. These findings revealed that garlic can be used as a natural feed additive to improve fish resilience against HM stress in aquatic environments.

Physiological and histopathological effects of polystyrene and polyethylene terephthalate microplastics and their binary mixture in a ground beetle ( Blaps polychresta )

Microplastic (MP) contamination of soils is increasing, yet mechanistic evidence for mixture toxicity in terrestrial insects remains limited. We investigated the sub‐chronic (30‐day) dietary effects of polystyrene (PS‐MP), polyethylene terephthalate (PET‐MP) and their binary mixture (1% PS + 1% PET; total 2% w/w) on the ground beetle Blaps polychresta . Endpoints included defecation rate, digestive enzyme activities (amylase and protease), oxidative stress biomarkers (reactive oxygen species [ROS], catalase [CAT] and superoxide dismutase [SOD]) and histopathological alterations in the midgut and testis. Survival was unaffected; however, PS and PET individually reduced defecation rate, whereas the mixture did not further exacerbate gut motility impairment. All treatments significantly altered digestive physiology, with increased amylase and reduced protease activity and the strongest imbalance occurring in the mixture group. ROS levels were elevated in both midgut and testicular tissues, accompanied by significant upregulation of CAT and SOD, indicating oxidative stress–mediated responses. Histological investigation revealed epithelial disruption and muscle disorganization in the midgut and degeneration of testicular follicles, vacuolization, pyknosis of spermatocytes and reduced follicular integrity. Trypan blue staining confirmed increased cellular damage in the testes following MP exposure. Testicular follicle diameter decreased in PS‐ and PET‐exposed beetles, indicating impaired spermatogenesis. Overall, chronic ingestion of PS and PET disrupts digestive and male reproductive physiology through oxidative stress–linked mechanisms, with mixture exposure intensifying several biochemical and histopathological effects. These findings highlight the importance of incorporating polymer interactions into terrestrial insect risk assessments.