Pathogenic infection of fishes is an important constraining factor affecting marine aquaculture. Insufficient understanding of the molecular mechanisms has affected the diagnosis and corresponding treatment. Here, we reported the dynamic changes of gene expression patterns in the Chinese tongue sole kidney at 16 h, 48 h, 72 h and 96 h after Vibrio harveyi infection. In total, 366, 214, 115 and 238 differentially expressed genes were obtained from the 16 h−vs. −C, 48 h−vs. −C, 72 h−vs. −C and 96 h−vs. −C group comparisons, respectively. KEGG enrichment analysis revealed rapid up-regulation of several immune-related pathways, including IL-17, TNF and TLR signaling pathway. More importantly, time-series analyses of transcriptome showed that immune genes were specifically up-regulated in a short period of time and then decreased. The expression levels of chemokines increased after infection and reached a peak at 16 h. Specifically, Jak-STAT signaling pathway played a crucial role in the regulation during Vibrio harveyi infection. In the later stages of infection, genes in the neuroendocrine pathway, such as glucocorticoid-related genes, were activated in the kidney, indicating a close connection between the immune system and neuroendocrine system. Our dynamic transcriptome analyses provided profound insight into the gene expression profile and investigation of immunogenetic mechanisms of Chinese tongue sole.

Grass carp (Ctenopharyngodon idella) is an important freshwater aquaculture species in China. However, high-density farming often leads to significant growth differentiation among individuals, seriously affecting yield and product quality. Here, we conducted an integrated transcriptomic and data-independent acquisition (DIA) proteomic analysis across the brain, liver, and muscle tissues of fast-growing (FG) and slow-growing (SG) grass carp after 9 months of high-density culture. Our analysis revealed that the core mechanism driving growth differentiation is a deep decoupling of transcription and translation, where enhanced muscle translational efficiency dictates the fast-growth phenotype, while slow growth is constrained by central stress and hepatic energy depletion. In the slow growth group, the brain exhibited translational arrest and neuroinflammation, and the liver entered a state of hypermetabolism mediated by AMPK, evidenced by the post-transcriptional up-regulation of key sensors such as CAB39 (PRM ratio = 1.634) and CAMKK2 (PRM ratio = 1.295). Conversely, in the fast-growing group, the mTOR–ribosome signaling axis was strongly activated at the post-transcriptional level in the muscle (GSEA NES = −1.852), triggering myofibrillar protein deposition despite transcriptional silence in classical growth pathways. These findings elucidate the systemic molecular mechanisms of growth divergence and provide high-confidence molecular targets for developing fast-growing, stress-resilient grass carp strains for precision aquaculture breeding.

Nanoplastics (NPs) are emerging aquatic pollutants that may threaten farmed fish health. This study evaluated whether dietary nanocurcumin (NCUR) modulates NP-associated biological disturbances in largemouth bass (Micropterus salmoides). A total of 480 fish (initial weight 11.52 ± 0.02 g) were assigned to four treatments for 21 days: control, 0.2% NCUR, 100 μg/L NPs, and 0.2% NCUR + 100 μg/L NPs. NP exposure significantly reduced growth and feed intake (p < 0.05) and was accompanied by gill, hepatic and intestinal tissue alterations, disturbed serum lipid parameters, changes in hepatic antioxidant enzyme activities, and altered mRNA expression of antioxidant- and metabolism-related genes. Dietary NCUR was associated with partial modulation of several NP-associated responses, including hepatic and intestinal structural alterations, serum lipid changes, adaptive antioxidant enzyme responses, and transcriptional changes in Nrf2/Keap1- and SIRT1/FoxO1-associated genes. However, NCUR did not alleviate NPs-induced gill damage, and NCUR alone also caused branchial histopathological alterations. Therefore, 0.2% NCUR may partially mitigate selected NPs-induced disturbances in M. salmoides, but its independent effects, branchial safety, and pathway-level mechanisms require further investigation.

Grass carp (Ctenopharyngodon idella) is a major freshwater aquaculture species in China, but its growth is limited under intensive high-density farming. This study aimed to investigate the characteristics of plasma exosomes associated with distinct growth performance by isolating and characterizing exosomes from fast- and slow-growing grass carp after nine months of culture. Exosomes showed typical morphology and expressed characteristic markers (CD63, CD81, TSG101). Small RNA sequencing identified 3325 miRNAs, with 177 highly abundant miRNAs differentially expressed: immune-related miRNAs were upregulated, while development-inhibitory miRNAs were downregulated in fast-growing fish. Target gene enrichment highlighted pathways in neural and skeletal development and amino acid metabolism. Integrative analysis across tissues revealed 26 miRNAs with coordinated expression patterns between plasma exosomes and brain, liver, or muscle, validated by qPCR. DIA proteomics quantified 4203 proteins, identifying 843 differentially enriched proteins linked to immune response, energy metabolism, and endoplasmic reticulum stress. Notably, TYMP was upregulated in muscle and exosomes, while several proteins (e.g., GYG2, BHMT) showed coordinated downregulation across tissues and exosomes in large fish. These results provide comprehensive evidence of exosome-mediated cross-tissue communication in teleosts and suggest a potential role for plasma exosomal miRNAs and proteins as non-invasive biomarkers correlated with growth status in aquaculture.

Backgrounds: Largemouth bass ( Micropterus salmoides ) is an economically important aquaculture species, but its pronounced intolerance to high‐carbohydrate diets often leads to metabolic liver disorders and compromised growth, limiting the practical application of cost‐effective high‐carbohydrate feeds in aquaculture. Lipid nanoparticles (LNPs) have shown promise in regulating glucose metabolism in mammals, but their efficacy and size‐dependent effects in fish remain unelucidated. Objective: LNPs were evaluated as novel potential additives to enhance the glucose utilization in M. salmoides under high‐glucose (HG) feeding conditions, addressing the issues of glucose intolerance and thereby reducing breeding costs. Methods: We constructed LNPs to serve as a feed additive for modulating the glucose metabolism in M. salmoides . We prepared LNPs with five different particle sizes (60, 125, 150, 175, and 200 nm) by varying the formulation ratio of the preparation. To obtain further results, the regulatory effect of LNPs on glucose metabolism in M. salmoides was verified through gavage administration. The expression levels of genes associated with glucose metabolism in M. salmoides were observed following acute (one administration) treatment with HG feeding to investigate the relevance between LNPs and glucose metabolism induced by HG in M. salmoides . Results: HG exposure activated the hepatic PI3K/AKT pathway, upregulated the expression of gluconeogenesis‐related genes ( foxo1 and g6pase ), and disrupted the expression of glycogenesis‐related genes ( gsk3 and gys1 ), leading to impaired glucose metabolism in M. salmoides —a key pathogenesis of high‐carbohydrate‐induced metabolic disorders. Notably, LNPs with 150–200 nm sizes specifically upregulated intestinal glut5 mRNA expression (but not glut2 ), intestinal GLUT5 is a critical hexose transporter: traditionally recognized for mediating fructose transport, it also facilitates glucose crossing the intestinal epithelial barrier to enter the bloodstream, providing the foundation for subsequent systemic glucose metabolism, and 150 nm LNPs exhibited the most rapid efficacy: they modulated the hyperactivated PI3K/AKT pathway, reversed the abnormal expression of foxo1 , g6pase , gsk3 , and gys1 induced by HG, and improved insulin sensitivity by upregulating irs1 and insr mRNA levels. Conclusion: 150 nm LNPs effectively ameliorate high‐carbohydrate‐induced metabolic damage by targeting GLUT5 to enhance intestinal glucose absorption and regulating the PI3K/AKT‐gluconeogenesis/glycogenesis cascade, providing a targeted solution for improving HG feed utilization in carnivorous fish aquaculture.