Search Results (62)

The Chinese soft-shelled turtle (Pelodiscus sinensis) is an important aquaculture species in China, and proper follicular development is crucial for its reproduction. Collagen plays a critical role in ovarian development, yet its effects in this species remain unclear. Using primary granulosa cells and ovarian tissue, we found that collagen content varied dynamically throughout follicular development and peaked at the mid-vitellogenic stage. Collagen reduction resulted in granulosa cell detachment, inhibited proliferation, induced nuclear vacuolation, and arrested the cell cycle. Collagen reduction also caused a persistent increase in ERK1/2 phosphorylation over 24 h, which was associated with downregulation of CCNE1, CDK2, and BCL2; pharmacological inhibition of ERK1/2 phosphorylation partially restored the expression of these genes. These results indicate that collagen is involved in ovarian development, and its reduction may inhibit granulosa cell proliferation, at least in part, through persistent ERK1/2 activation. Our findings, obtained from an experimentally manipulated in vitro system, provide insights for in vitro culture of chelonian granulosa cells and ovarian tissues. Full article

This study aimed to isolate and identify angiotensin I-converting enzyme (ACE) inhibitory peptides from Chinese soft-shelled turtle (Pelodiscus sinensis Wiegmann) meat. A total of 80 peptides were identified from the active fractions of the papain hydrolysate of the Pelodiscus sinensis meat water-soluble protein, including 78 unique peptides; among them, 47 had identification scores above 50. Of these, 10 peptides were predicted to possess ACE inhibitory potential, good water solubility, and no toxicity and were therefore synthesized for further evaluation. Peptide YK-17 showed the strongest ACE inhibitory activity among the synthesized peptides, with an IC₅₀ value of 479.3 μM, while peptide GK-18 possessed the strongest inhibitory effect on the viability of the hepatic stellate cell line HSC-T6. Molecular docking further indicated that YK-17 formed more hydrogen bonds with N-ACE than with C-ACE, suggesting that YK-17 exhibited stronger hydrogen bonding interactions with N-ACE. These findings suggest that Pelodiscus sinensis meat is a promising source of functional peptides with potential antihypertensive activity and liver fibrosis-related bioactivity. Full article

Converting conventional rice monoculture to co-culture with fish is a common strategy to increase farmers’ incomes. The Chinese soft-shell turtle is a typical high-value species for paddy co-culture, but the effects of the co-culture system (RT) on greenhouse gas emissions (GHG) are poorly understood. This study evaluated the impacts of RT on economic benefits and greenhouse gas emissions. Our results showed that RT co-culture did not significantly increase rice yield, but it provided additional income from turtle sales, increasing net profits. GHG emission responses to RT differed between the two farms. In farm 1, RT increased CH₄ emissions from the rice-cultivated area but decreased them from the turtle culture area, resulting in no net effect on total CH₄ emissions. The reduction of CH₄ emissions in the turtle culture area was associated with lower DOC content and reduced methanogenic gene mcrA abundance. In farm 2, RT reduced CH₄ emissions from both areas, lowering total CH₄ emissions by 36.5%, which was linked to less water flooding and higher methanotrophic gene (pmoA) abundance. Total N₂O emissions were not significantly affected by RT at either farm. RT increased indirect GHG emissions, but these accounted for only 7.2–16.9% of total emissions. Overall, RT reduced total GHG emissions by 27.7% at farm 2, with no significant change at farm 1. These findings suggest that RT can enhance economic benefit while lessening total GHG emissions. Full article

This study was designed to assess the protective efficacy of dihydromyricetin (DHM) against intestinal injury in Chinese soft-shelled turtles (Pelodiscus sinensis) caused by partial replacement of fishmeal (FM) with fermented rapeseed meal (FRM), and to uncover the molecular mechanisms involved. Turtles were fed an FM-based control diet, an FRM-substituted diet, or FRM diets supplemented with DHM at 0.5‰ (DHMT1), 1.0‰ (DHMT2) or 2.0‰ (DHMT3) for 8 weeks. Growth performance, digestive enzyme activities, antioxidant parameters, inflammatory cytokines, and intestinal histomorphology were assessed, and intestinal transcriptomics and metabolomics were also performed. FRM replacement significantly improved growth performance; however, this beneficial effect was accompanied by notable intestinal mucosal oxidative damage, as evidenced by decreased villus height, increased lumen space, and lamina propria edema, along with elevated pro-inflammatory cytokines (IL-1β and TNF-α) and MDA content, alongside reduced GSH and CAT activities. DHM supplementation dose-dependently ameliorated these adverse effects by restoring mucosal integrity, digestive enzyme activities, redox homeostasis, and inflammatory balance, ultimately improving growth performance. Transcriptomic KEGG analysis revealed that DHM enriched pathways related to glycerophospholipid metabolism, glutathione metabolism, drug metabolis-cytochrome P450, and polyunsaturated fatty acid metabolism. Metabolomics further confirmed dose-dependent remodeling of phospholipids and bile acids. Integrated omics demonstrated that DHM likely regulates detoxification, anti-inflammatory, membrane repair, and antioxidant pathways. In conclusion, DHM demonstrates a protective effect against FRM-induced intestinal mucosal oxidative damage in P. sinensis, which may be mediated by a synergistic combination of enhanced detoxification, anti-inflammatory modulation, restoration of phospholipid membrane integrity, and reinforcement of antioxidant defenses. Full article

Reducing reliance on supplemental fish oil is central to sustainable aquaculture, but the molecular consequences of replacing it with vegetable oils remain poorly characterized in the juvenile Chinese soft-shelled turtle (Pelodiscus sinensis). We evaluated whether full substitution of the supplemental dietary fish oil (FO) with linseed oil (LO) or soybean oil (SO) compromises hepatic lipid metabolism in Pelodiscus sinensis. Three isonitrogenous and isolipidic diets, sharing identical fish meal and other ingredient bases and differing only in the supplemental lipid (4% FO, LO or SO), were fed to triplicate groups of juvenile turtles (initial body weight 55.0 ± 0.05 g) for 8 weeks. Growth performance, survival, feed conversion ratio, and serum biochemistry were unaffected. However, both vegetable oil diets altered tissue fatty acid composition, raising n-6 PUFA and lowering n-3 LC-PUFA and the n-3/n-6 ratio in liver and muscle (muscle EPA and DHA each decreased by approximately 40%); the SO group additionally exhibited elevated hepatic malondialdehyde, whereas hepatic lipid droplet area and lipid content did not differ significantly among groups. Liver transcriptomic profiling identified 262 (LO vs. FO) and 214 (SO vs. FO) differentially expressed genes, converging on lipid storage and bile acid metabolism. RT-qPCR confirmed the up-regulation of PLIN3, G0S2 and APOF and the down-regulation of CYP7A1. Over 8 weeks, replacement of supplemental FO maintained growth without overt impairment while altering tissue fatty acid profiles and the hepatic expression of key lipid metabolism genes. Full article

The physiological and metabolic responses of juvenile Chinese softshell turtles, Pelodiscus sinensis, exposed to single or double heatwaves (33 °C for 4 days) were investigated based on liver antioxidant assay and transcriptomic and metabolomic analyses. Heatwave exposure increased superoxide dismutase and catalase activities, but did not significantly alter malondialdehyde and reactive oxygen species levels, indicating enhanced antioxidant defense. Transcriptomic analysis revealed the differential expression of genes involved in carbohydrate metabolism, immune function, cardiovascular regulation, and signal transduction, with more pronounced alterations in single-heatwave-exposed turtles. Additionally, metabolic dysregulation in amino acids was revealed by significantly altered levels of some key amino acids and their derivatives. Compared with single-heatwave-exposed turtles, fewer differentially expressed genes and less metabolic disruptions in double-heatwave-exposed turtles probably indicated less physiological disorders under recurrent heat stress. Although P. sinensis can adopt physiological and metabolic adjustments to mitigate the adverse effects of short-term heatwaves, repeated heatwave exposure might still cause severe physiological consequences in aquatic turtles. These findings may have important implications for the conservation of freshwater turtle species under future climate change scenarios. Full article

In this study, Chinese medicinal herbs were evaluated as potential antibiotic substitutes for Chinese soft-shelled turtle (Pelodiscus sinensis). Forty-five herbs were initially screened for antibacterial activity against Salmonella enteritidis, Escherichia coli, and Shigella flexneri. Nine herbs exhibiting broad-spectrum inhibitory effects were selected and subjected to microbial fermentation, after which their antibacterial activities were reassessed and applied as dietary supplements in feeding trials. The results showed that fermentation altered the antibacterial activities of several herbs and enhanced their overall functional performance. Dietary supplementation with fermented Chinese herbal medicine did not adversely affect feed utilization but significantly improved hematological parameters, liver and kidney function indicators, antioxidant capacity, and nonspecific immune responses. Furthermore, turtles fed fermented herbal diets exhibited higher survival rates following bacterial challenge. Intestinal microbiota analysis based on 16S rRNA gene sequencing indicated that fermented herbal supplementation modulated microbial community structure by reducing potential pathogens and increasing beneficial bacterial taxa associated with intestinal health. These findings suggest that microbial fermentation effectively enhances the biological efficacy of Chinese medicinal herbs. Fermented herbal feed additives represent a promising green alternative to antibiotics for soft-shelled turtle aquaculture. The global ban on prophylactic antibiotics drives the need for safe, effective feed alternatives. Microbial fermentation of Chinese herbs (FCM) is proposed to enhance efficacy and detoxification, but its comprehensive effects in aquaculture require deeper investigation. This study evaluated compound unfermented (CM) and fermented (FCM) Chinese herbal supplements on the Chinese soft-shelled turtle (Pelodiscus sinensis). Initial screening showed fermentation generally enhanced the antibacterial activity of the herbs against common enteric pathogens (S. enteritidis, E. coli, S. flexneri). Results indicated that the FCM diet significantly improved physiological status, leading to higher red blood cell counts, better liver/kidney function (reduced ALT/AST, UREA), and stronger immune/antioxidant responses (increased Lysozyme and T-AOC) compared to CM or control diets. Critically, the FCM group achieved the highest survival rates across all single and combined pathogen challenges, demonstrating superior protective efficacy. Furthermore, FCM effectively modulated the gut microbiota, enriching beneficial fermentative bacteria. In conclusion, microbial fermentation significantly amplifies the health-promoting and protective benefits of Chinese herbal supplements in soft-shelled turtles, positioning FCM as a promising green alternative for disease control in aquaculture. Full article

The carapace of the Chinese soft-shelled turtle (Pelodiscus sinensis) is rich in collagen and stands as a crucial economic trait for assessing its quality, as well as a key indicator for selective breeding. However, current studies on the mechanisms underlying collagen deposition in the carapace remain severely limited, significantly hindering progress in selective breeding. Here, the Col1a2 gene of P. sinensis was molecularly characterized for the first time. Analysis of gene structure, phylogenetic tree, and amino acid sequence homology revealed that Col1a2 is relatively conserved among tetrapods but divergent from fishes. Collinearity analysis identified the BET1-COL1A2-CASD1-SGCE gene block shared across all 14 representative vertebrates and found that the Col1a2 is located on the Z chromosome of Thamnophis elegans. Tissue expression analysis showed that Col1a1 was highly expressed in the heart, gonad, and lung. Additionally, Col1a1 expression levels markedly increased during carapace development, exhibiting a strongly positive correlation with the changes in collagen content of the carapace. In situ hybridization results revealed strong signal for the Col1a2 transcripts in fibroblasts of the dermal layer of P. sinensis carapace. Knockdown of the Col1a2 gene in the carapace cells of P. sinensis significantly reduced collagen content. Transcriptome analysis following Col1a2 knockdown identified several differentially expressed genes associated with collagen deposition, including Fbln2, IL-11, and Rspo4, as well as significantly enriched pathways such as the JAK-STAT signaling pathway, the apelin signaling pathway, and the Hippo signaling pathway. Our findings offer a molecular basis for elucidating the mechanisms of collagen deposition in the carapace of P. sinensis, while also supplying a potential target for the selective breeding of collagen-rich strains of P. sinensis. Full article

Sharp declines in temperature pose a significant risk for mass mortality events in the Chinese soft-shelled turtle (Pelodiscus sinensis). To assess the effects of acute cold stress on intestinal health, turtles were exposed to temperatures of 28 °C (control), 14 °C, and 7 °C for 1, 2, 4, 8, and 16 days. The results showed that acute cold stress at 14 °C and 7 °C induced time-dependent alterations in intestinal morphology and histopathology. The damage was more severe at 7 °C, characterized by inflammatory cell infiltration, lymphoid hyperplasia, and extensive detachment and necrosis across the villi, muscle layer, and submucosa. 16S rDNA sequencing revealed significant shifts in intestinal microbiota composition in the 7 °C group, dominated by Helicobacter and Citrobacter. Transcriptomic analysis identified differentially expressed genes (DEGs) that respond to acute cold stress and are involved in the Toll-like receptor signaling pathway (Tlr2, Tlr4, Tlr5, Tlr7, and Tlr8), the NOD-like receptor signaling pathway (Traf6, Traf2, Casr, Rnasel, Pstpip1, Plcb2, Atg5, and Mfn2), apoptosis (Tuba1c, Ctsz, Ctsb, Kras, Hras, Pik3ca, Bcl2l11, Gadd45a, Pmaip1, Ddit3, and Fos), and the p53 signaling pathway (Serpine1, Sesn2, Ccng2, Igf1, Mdm2, Gadd45a, Pmaip1, and Cdkn1a). Metabolomic profiling highlighted differentially expressed metabolites (DEMs) that cope with acute cold stress, such as organic acids (oxoglutaric acid, L-aspartic acid, fumaric acid, DL-malic acid, and citric acid) and amino acids (including L-lysine, L-homoserine, and allysine). The integrated analysis of DEGs and DEMs underscored three key pathways modulated by acute cold stress: linoleic acid metabolism, neuroactive ligand–receptor interaction, and the FoxO signaling pathway. This study provides a comprehensive evaluation of intestinal health in Chinese soft-shelled turtles under acute cold stress and elucidates the underlying mechanisms. Full article

The infectious diseases have become more frequent with the production of farmed Chinese soft-shelled turtles (Pelodiscus sinensis) increasing. In this study, bacterial strain was isolated, identified, and characterized from the liver of diseased Chinese soft-shelled turtles exhibiting body surface hemorrhages, claws and tail tips necrosis, and bleeding spots in visceral tissues. Based on the analysis results of morphology, biochemistry, and 16S ribosomal RNA (16S rRNA) sequencing, one bacterium Providencia rettgeri (P. rettgeri) was identified. The histopathological examination results revealed varying degrees of tissue damage in the spleen, liver, kidneys, and intestines of individuals with P. rettgeri. Challenge experiments results confirmed that the P. rettgeri caused morbidity and mortality in healthy Chinese soft-shelled turtles, reproducing similar clinical symptoms of naturally infected individuals. And, its mortality rate was up to 91% in the highest concentration group. Screening of eight virulence-associated genes results revealed that this P. rettgeri strain carried virulence factors including invasion protein gene, alpha-hemolysin, and others which were considered to contribute to pathogenicity. Antibiotic susceptibility testing showed that the bacterium was sensitive to amikacin and ciprofloxacin, which may be effective therapeutic options. In conclusion, this bacterium P. rettgeri was the pathogen that caused this disease in Pelodiscus sinensis. These results provide valuable research basis for the disease prevention and control of Pelodiscus sinensis farming. Full article

Background/Objectives: The Sox transcription factor family is critical for gonadal development and sex differentiation in animals, yet its roles in chelonians, particularly in the Chinese soft-shelled turtle (Pelodiscus sinensis), have rarely been investigated. Methods: This study cloned and analyzed the cDNA sequences of Sox3 and Sox30 genes from P. sinensis, examining their amino acid sequences and structural properties. Real-time quantitative PCR (RT-qPCR) was used to assess the expression of these two genes in different adult tissues and at various stages of embryonic gonadal development. Additionally, the effects of exogenous hormones (17β-estradiol, E₂ and 17α-Methyltestosterone, MT) on the expression of Sox3 and Sox30 were also investigated. Results: The results indicated that Sox3 showed significantly elevated expression in female gonads, kidney, brain, liver, lung, spleen, and muscle relative to male counterparts, displaying a female-biased expression pattern. In contrast, Sox30 showed a male-biased pattern, with higher expression in male gonads, spleen, muscle, brain, and liver than in females, showing expression. Both genes were expressed at low levels. Exogenous hormone treatments revealed that MT significantly downregulated Sox3 expression in female embryos, whereas E₂ significantly enhanced Sox3 expression in male embryos. Furthermore, MT treatment significantly upregulated Sox30 expression in female embryos, and E₂ treatment also significantly increased Sox30 expression in male embryos. Conclusions: These findings suggest that Sox3 and Sox30 play crucial roles in the gonadal development of P. sinensis, with Sox3 potentially involved in ovarian development and Sox30 in testicular maturation. Both genes are regulated by exogenous hormones, highlighting their importance in sex differentiation and gonadal development. This study provides valuable theoretical insights for further exploration of the molecular mechanisms of sex regulation in reptiles. Full article

To explore the current state of genetic diversity of in the Chinese soft-shelled turtle (Pelodiscus sinensis) in the Dongting Lake basin, the genetic diversity of five sub-populations consisting of 71 turtles were analyzed through mitochondrial Cytb and 12S rRNA. Our results revealed 13 haplotypes for Cytb and 6 for 12S rRNA. The overall haplotype diversity and nucleotide diversity indices were 0.750 and 0.014, and 0.712 and 0.009, respectively. The Shaoyang sub-population showed the lowest genetic diversity according to both markers. The genetic distances between sub-populations ranged from 0.010 to 0.018 (Cytb), and from 0.002 to 0.014 (12S rRNA), with the largest distance observed between the Shaoyang and Junshan sub-populations. The Junshan sub-population was significantly different from the other sub-populations (p < 0.05), and gene exchange was weak, despite belonging to the same population. Genetic variation within the P. sinensis sub-population was much higher than that between sub-populations. There was no recent expansion event in the history of P. sinensis. Overall, the genetic diversity of P. sinensis was high, whereas it appeared to be homogenous, suggesting a potential decline in genetic diversity. This study provides valuable insights for the conservation and sustainable use of P. sinensis. Full article

In farmed animals, body color is not only an ecological trait but also an important trait that influences the commercial value of the animals. Melanin plays an important role in the formation of body color in animals, while the tyrosinase (TYR) gene family is a group of key enzymes that regulate melanogenesis. The Chinese soft-shelled turtle (Pelodiscus sinensis) is one of the most important reptiles in freshwater aquaculture. However, the potential role of the TYR gene family in the body color formation of P. sinensis remains unclear. This study aimed to investigate the expression and conservation of the TYR gene family in relation to body color variation in P. sinensis. Three core members of this gene family were identified from the P. sinensis genome. Following identification, the genomic features were analyzed. They shared similar physicochemical properties and conserved domains. Chromosome mapping showed that the three genes of P. sinensis were all located on the autosomes, while phylogenetic and collinearity analysis suggested that the protein functions of the three genes in the studied species were highly conserved. Amino acid sequence alignment indicated high conservation among the three TYR gene family proteins (TYR, TYRP1, and DCT) in multiple critical regions, particularly in their hydrophobic N-/C-terminal regions and cysteine/histidine-rich conserved domains. The qRT-PCR revealed that the TYR and DCT genes were highly expressed in the eyes of individuals with different body colors. The expression levels of TYR and TYRP1 genes in the skin were significantly higher in dark-colored individuals than in light-colored ones (p < 0.05). These results will lay the groundwork for functional studies and breeding programs targeting color traits in aquaculture. Full article

The rapid increase in drug resistance in recent years has become a significant global public health concern. Escherichia coli are ubiquitous bacteria, widely distributed in various environments. This study isolated a bacterial strain (HD-593) from diseased Chinese soft-shelled turtles (Pelodiscus sinensis). The bacterium was identified based on morphology, biochemical tests, and 16S rRNA sequencing, confirming it as E. coli. Drug susceptibility tests revealed that the HD-593 strain was highly resistant to ceftriaxone, enrofloxacin, doxycycline, sulfadiazine, gentamicin, neomycin, florfenicol, carbenicillin, cefradine, erythromycin, penicillin, ampicillin, midecamycin, and streptomycin. Resistance gene analysis confirmed the presence of quinolone resistance genes (oqxA and oqxB), aminoglycoside resistance genes (aac(3)-II and aphA1), a β-lactam resistance gene (blaTEM), and an acylaminol resistance gene (floR) in HD-593. The median lethal dose (LD50) of HD-593 for P. sinensis was 6.53 × 10⁵ CFU/g. Biochemical analysis of serum revealed that HD-593 infection caused a significant reduction in total protein, albumin, and globulin levels, while markedly increasing the levels of aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase. Histopathological analysis revealed severe intestinal damage characterized by villi detachment and muscle cell necrosis. Additionally, extensive splenocyte necrosis with nuclear marginalization, glomerular swelling, and pronounced hepatic steatosis accompanied by distended sinusoids were observed. This study identified a multidrug-resistant E. coli strain from deceased P. sinensis, suggesting that drug resistance genes may circulate in aquaculture ecosystems, posing potential risks to aquaculture. Full article

D-glucuronolactone (DGL), a hepatoprotective compound widely used in clinical and energy products, was evaluated for its effects on Chinese soft-shelled turtles (Pelodiscus sinensis) through an 8-week feeding trial with dietary supplementation (0, 200, and 400 mg kg⁻¹). DGL did not alter survival or feed intake, but induced dose-dependent growth improvements, including increased final body weight, weight gain rate, specific growth rate, and muscle/liver glycogen, alongside reduced feed conversion ratio and muscle and liver fat. Serum analysis showed decreased activities of alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, and reduced low-density lipoprotein cholesterol, total cholesterol, and triacylglycerols. Antioxidant indices revealed elevated catalase and superoxide dismutase (SOD) activities in serum and intestine, coupled with reduced malondialdehyde, though hepatic SOD activity declined. Histologically, 400 mg kg⁻¹ DGL alleviated liver lesions without impacting intestinal morphology. Molecular analyses demonstrated upregulated muscle mTOR signaling genes (mTOR, IGF1, S6K1) but downregulated hepatic/intestinal mTOR and IGF1 expression. DGL also suppressed inflammatory cytokines (TNF-α, IL-1β, IL-10) in liver and intestine. Challenge tests with Aeromonas hydrophila confirmed the enhanced disease resistance in DGL-supplemented turtles. These findings highlight DGL’s potential as a nutritional strategy to enhance growth, antioxidant capacity, and health in intensive turtle farming. Full article