N-(1,3-dimethylbutyl)-N’-phenyl-p-benzoquinone (6PPD-Q) is an emerging environmental contaminant that is widely distributed in aquatic environments and presents significant toxicological risks to aquatic organisms. As 6PPD-Q is primarily derived from oxidative transformation of the tire antioxidant N-(1,3-dimethylbutyl)-N’-phenyl-p-phenylenediamine (6PPD), its persistence and potential for bioaccumulation in aquatic organisms have raised widespread concerns. This study reviews the environmental sources, spatial distribution, migration, and transformation behaviors of 6PPD-Q, as well as its degradation mechanisms in different environmental media. Additionally, this review systematically explores the toxicological effects of 6PPD-Q on aquatic organisms, including its physiological, biochemical, and molecular impacts on fish, crustaceans, mollusks, and algae, with a focus on potential toxicological mechanisms. Finally, we discuss the limitations of current research on 6PPD-Q and propose key directions for future studies, including long-term ecological risk assessments, mechanisms of bioaccumulation, metabolic pathway analysis, and optimization of pollution control strategies, aiming to provide a scientific basis for the ecological risk assessment and pollution management of 6PPD-Q.

Toxic effects of abamectin on non-target aquatic organisms have been well documented due to its extensive use in both agricultural and aquacultural areas. However, knowledge of the abamectin induced cytotoxicity in crustacean hepatopancreas is still incomplete. In this study, we investigated the cytotoxic effects of abamectin on hepatopancreas cells of Chinese mitten crab, Eriocheir sinensis by an in vitro assay. The results showed that abamectin inhibited cell viability with elevated reactive oxygen species (ROS) and malondialdehyde (MDA) levels in a dose-dependent manner. Increased olive tail moment (OTM) values and 8-hydroxy-2'-deoxyguanosine (8-OHdG) contents indicate the DNA damage under abamectin exposure. The up-regulation of the typical apoptosis-related protein BCL2-associated X protein (Bax) and the down-regulation of B cell leukemia/lymphoma 2 (Bcl-2) demonstrate apoptosis in hepatopancreas cells. Meanwhile, the activities of both caspase-3 and caspase-9 were increased, indicating caspase-mediated apoptosis. In addition, qRT-PCR results showed the up-regulation of antioxidant genes superoxide dismutase (SOD) and catalase (CAT). The mRNA expression of Cap 'n' Collar isoform-C (CncC) and c-Jun NH2-terminal kinases (JNK) was also significantly increased, implying the involvement of the Nrf2/MAPK pathway in the antioxidative response. The alteration of innate immune-associated genes Toll-like receptor (TLR) and myeloid differentiation primary response gene 88 (Myd88) also indicates the influence of abamectin on immune status. In summary, the present study reveals the cytotoxicity of abamectin on hepatopancreas cells of E. sinensis and this in vitro cell culture model could be used for further assessment of pesticide toxicity.

This study investigates the impact of different diets on fish growth and bacterial community structure present in the intestine of goldfish (Carassius auratus) and their aquaculture water under recirculating water conditions. We assumed that different types of diet would form different intestinal microbiota that may affect host growth. Using Illumina MiSeq high-throughput sequencing, we analyzed bacterial communities in goldfish fed with formulated pellet feed, Tubifex worms (Limnodrilus hoffmeisteri), and an alternating diet of both. Over a 14-day feeding trial, no significant differences in juvenile goldfish growth were observed between groups. After 7 days, diet changes significantly influenced the abundance and diversity of intestinal bacteria, with the alternating diet notably enhancing bacterial diversity in both the intestines and water. However, these differences in bacterial diversity decreased by day 14. The results indicate that diet type affects microbial community diversity in the intestines and water of goldfish, and that goldfish intestines maintain a stable core bacterial community structure. This highlights the potential for optimizing diet types to enhance microbial health and stability in aquaculture systems and, in addition, provides an important scientific basis for alternative diets in goldfish aquaculture in the industry.

Puerarin, a bioactive isoflavone extracted from Pueraria lobata, possesses well-documented pharmacological properties, including anti-inflammatory, antioxidant, and metabolic regulatory effects, which have been extensively studied in mammalian models and traditional medicine. Recently, its potential as a functional feed additive in aquaculture has garnered increasing attention. This study aimed to evaluate the effects of dietary puerarin supplementation on growth performance, immune response, antioxidant capacity, and disease resistance in largemouth bass, Micropterus salmoides. A total of 120 fish were randomly assigned to 4 dietary groups, receiving a basal diet supplemented with 0 (control), 200, 500, and 1000 mg/kg puerarin for 8 weeks. The results showed that dietary puerarin significantly (p < 0.05) improved weight gain, with the 200 mg/kg and 500 mg/kg groups exhibiting the best performance. Puerarin supplementation enhanced acid phosphatase (ACP), alkaline phosphatase (AKP), and lysozyme (LZM) activities, reduced malondialdehyde (MDA) levels, and increased superoxide dismutase (SOD) and catalase (CAT) activities, indicating improved immune function and oxidative stress resistance in groups receiving medium concentrations of puerarin supplementation. The expression of the TNF-α, IL-6, IL-8, and HSP70 genes was significantly downregulated, especially in the 200 mg/kg and 500 mg/kg groups, suggesting anti-inflammatory and anti-stress effects, while Nrf2 expression was upregulated in the 1000 mg/kg group, reinforcing its antioxidative role. Additionally, puerarin-fed fish exhibited significantly lower mortality rates following Aeromonas hydrophila infection, highlighting enhanced disease resistance. In summary, the dose-dependent effect of puerarin on largemouth bass aquaculture has been revealed in this study. Dietary supplementation with moderate doses of puerarin (200 and 500 mg/kg) effectively suppressed inflammation and enhanced immune function, while the highest dose (1000 mg/kg) may mildly activate the immune system. These findings suggest that puerarin is a promising phytogenic feed additive for improving fish health and aquaculture sustainability.