Gill Tissue Research Articles

Benzo[a]pyrene-induced oxidative stress-mediated apoptosis in gill tissue of fish, Channa punctatus

Benzo[a]pyrene-induced oxidative stress-mediated apoptosis in gill tissue of fish, Channa punctatus

Effectiveness of functional ingredients to enhance gill disease in Atlantic salmon (Salmo salar, L.).

The development and application of functional feed ingredients represents a great opportunity to advance fish growth and health, boost the immune system, and induce physiological benefits beyond those provided by traditional feeds. In the present study, we looked at the feasibility of in vitro methods for screening the qualities of functional feed ingredients using the fish cell line RTgill-W1, which has never been used in fish nutrition, and the culture of Paramoeba perurans. Five functional feed ingredients (arginine, β-glucan, vitamin C, and two phytogenic feed additives) were selected to investigate their effects on cell viability and reactive oxygen species production. Three of the selected ingredients (arginine and two phytogenic feed additives) were additionally tested to assess their potential amoebicidal activity. As these functional ingredients are the core of a commercially available feed (Protec Gill, Skretting AS), their beneficial effects were further assessed in a field trial in fish affected by complex gill disease. Here, the analyzed parameters included the evaluation of macroscopic and histopathological gill conditions, pathogen detections, and analyses of plasma parameters. RTgill-W1 cell line assays were a good tool for screening functional ingredients and provided information about the optimal ingredient concentration ranges, which can be helpful for adjusting the concentrations in future feed diets. Through the culture of P. perurans, the tested ingredients showed a clear amoebicidal activity, suggesting that their inclusions in dietary supplements could be a viable way to prevent microbial infections. A three-week period of feeding Protec Gill slowed the disease progression, by reducing the pathogen load and significantly improving gill tissue conditions, as revealed by histological evaluation. The use of diets containing selected functional ingredients may be a feasible strategy for preventing or mitigating the increasingly common gill diseases, particularly in cases of complex gill disease, as documented in this study.

Determination of Some Heavy Metals in Tissues of Binni Mesopotamichthys sharpeyi and Water in Al-Dalmaj Marsh/Iraq

The study was conducted in Al-Dalmaj marsh, considered one of the most important wetlands at the national and regional level and represents the most critical environment to form a good stock of Binni Mesopotamichthys sharpeyi in Iraq. The study assessed heavy metals in water and M. sharpeyi by detecting accumulation of (Nickel, Cadmium and Lead) in the tissues of gills, liver, and small intestines during the summer and winter seasons 2022-2023. The study results showed a high concentration of heavy metals in the water during summer compared to winter. Nickel levels ranged (0.19 ±0.627, 0.20 ±0.531) in water for both stations. The highest concentration was (1.339 mg/L) in suspended phase during summer, and ND in dissolved phase in winter, while Cadmium rates were (0.25±0.948, 0.17±0.478) in both stations respectively, the highest concentration was (1.827 mg/L) in suspended phase of station 1 during summer. Both stations ' lead rates were (0.39±1.455, 0.09±1.117). (3.176 mg/L) was the highest concentration in the suspended phase of station 1 during summer, while (0.121 mg/L) was the lowest in the suspended phase in winter. The results showed a sequence of concentrations of heavy metals in M. sharpeyi organs: Gills > Liver ≥ Small Intestines. The highest concentration rate of Nickel (4.109 & 3.692 mg/g) was recorded in small intestines and liver, respectively, during winter, the lowest rate (3.057 mg/g) was recorded in the gills during summer, the total of sedimentation rate of Ni in the liver and intestines was (3.726 mg/g), whereas (3.114 mg/g) in gills. Cadmium recorded an equal value of (0.957 mg/g) representing the highest percentage in the small intestines for both seasons. The highest concentrations (0.906 mg/g) in liver during summer. The total sedimentation rate of Cd in liver and small intestines was (0.852 mg/g), while (0.738 mg/g) was in gills. Lead recorded a high significant rate reaching to (8.501 mg/g) in gills during summer, followed by (6.115 mg/g) and (5.891 mg/g) in the liver and small intestines, respectively. Generally, lead reached the highest value for all elements assessed in fish at (8.501 mg/g) in the gills during summer, while (5.027 mg/g) was the highest rate in the liver during winter, and (3.709 mg/g) was the lowest rate in small intestines during winter. The total sedimentation rate of Pb in liver and small intestines was (5.185 mg/g), and (6.41 mg/g) was in the gills. Cadmium was recorded above the permissible (0.05 mg/g) limit by FAO [25] in the small intestine and liver, whereas lead exceeded the allowable limits (5 mg/g) by FAO/WHO [26]. Accordingly, the intake of these organs is unsafe for humans, and the registration of these high values poses a risk to the survival of this species as it can cause the death of fish in their environment under certain conditions.

Lambda-cyhalothrin'nin Oreochromis niloticus’un Solungaç Fosfolipid (PL) Alt Sınıfı Üzerine Etkisi

Fatty acids have a crucial role in providing energy and performing essential functions in living organisms. Moreover, these substances exhibit the most significant alterations in their structure based on ecotoxicological parameters when viewed from a biochemical perspective. These bioactive chemicals are present in the cellular architecture. The study of these fatty acids, crucial for maintaining the integrity and permeability of cell membranes, holds great significance for all living organisms. Consequently, doing fatty acid analysis specifically at the phospholipid level holds significant importance.
 The impact of lambda cyhalothrin on the fatty acid content of several phospholipid subclasses (phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylinositol (PI), and phosphatidylserine (PS) in the gill tissue of O. niloticus (Perciformes: Cichlidae) was assessed using gas chromatography. The alterations in the fatty acid composition was analyzed 21 days after exposure.
 Following the complete extraction of lipids from gill tissue, the tissue was subsequently separated into different subclasses of phospholipids using thin layer chromatography. The samples were subjected to methylation and then evaluated using Gas Chromatography to determine the percentage of the fatty acid. After doing the analysis, a grand total of 16 fatty acids were identified. The research revealed that the primary fatty acids were 16:0 and 18:0 of saturated fatty acids, monounsaturated 18:1n-9, and polyunsaturated 18:2n-6, 20:4n-6, and 22:6n-6. Upon analyzing the distribution of fatty acids, it was observed that PC, PE, and PI included 16:0, PE contained 18:1, PE and PS contained C18:2n-6 and 20:4n-6, and significant alterations in C22:6n-3 were detected in PE. Our investigation revealed that the n-3/n-6 ratio of fish in the PE subclass was the lowest when compared to PC, PI, and PS.

Spatial Distribution and Enrichment Dynamics of Foodborne Norovirus in Oyster Tissues.

The prevalence of norovirus in oysters poses a significant threat to food safety, necessitating a comprehensive understanding of contamination patterns. This study explores the temporal dynamics of norovirus distribution in various oyster tissues over a contamination period ranging from 6 to 96 h. Four tissues-the gill, palp, digestive gland, and stomach-were subjected to systematic monitoring using RT-qPCR for absolute quantification. Results revealed rapid norovirus detection in all tissues six hours post-contamination, with subsequent variations in detection rates. Gill and digestive gland tissues exhibited a peak in detection at 12-24 h, aligning with the oyster's gastrointestinal circulatory system. The digestive gland, distinguished by specific enrichment and adsorption capabilities, demonstrated the highest virus concentration at 48 h. In contrast, the stomach displayed a reemergence of norovirus. Beyond 72 h, detection remained exclusive to the digestive gland, with Ct values comparable to earlier time points. At 96 h, a limited amount of norovirus was detected in the digestive gland, emphasizing the importance for timely monitoring. In addition to providing critical insights into optimal detection strategies, these findings highlight the time-related characteristics of norovirus contamination in oysters. The study identifies the digestive gland as a key target for reliable monitoring, providing valuable data to improve protocols for reducing hazards associated with oyster consumption and foodborne norovirus infections. This research contributes to the understanding of norovirus dynamics in oyster tissues and reinforces current efforts aimed at ensuring food safety and public health.

New wine in old bottles: Modification of the Na+/K+‐ATPase enzyme activity assay and its application in salmonid aquaculture

AbstractThe Na+, K+ ATPase (NKA) enzyme is important to generate the transmembrane ion gradient in the gills, intestine, and kidneys, hence, is vital for secondary transport of fluids and different solutes in teleosts. Gill NKA enzyme activity is often used as a proxy for parr–smolt transformation (PST) during which anadromous salmonids prepare for seawater (SW). Increased intensification and production of larger smolts in modern salmonid aquaculture has resulted in reports of gill NKA activity being less reliable as a proxy for smolt quality. Consequently, changes in mRNA nka‐α1b/α1a ratios in gills are increasingly used as indicators of PST. However, nka isoform mRNA abundance may not reflect translation into the functional protein, nor the activity of the mature enzyme. This may limit the predictive power of molecular markers under certain environmental conditions, rearing regimes and biological scenarios. During PST, the osmoregulatory transformations necessary for SW tolerance and survival does not only occur in the gills. Equally important are the changes in ion transporting activities, including NKA activity, in the intestine and kidneys. However, to our knowledge, there are no previous studies addressing the timing and concurrent changes in NKA activity in the three osmoregulatory tissue during PST. Here we present modifications and optimization of the NKA enzyme activity protocols for gill, intestinal and kidney tissue and outline how to best utilize NKA activity measurements as part of a more holistic approach to evaluate overall smolt quality in modern aquaculture.

Protective Effects of Sanyar Prebiotic on Immunity and Tissue Changes of Common Carp (Cyprinus carpio) Exposed to CuSO4 Stress

Prebiotics, as feed additives, can activate the antioxidant and immune systems of fish and significantly improve the survival of aquaculture animals in stressful conditions. The exposure of fish to copper sulfate leads to oxidative stress, suppression of the immune system, and destruction of vital body tissues. This study aimed to investigate the protective effects of Sanyar prebiotic on the immunity and tissue changes of common carp (Cyprinus carpio) exposed to CuSO4 stress. Two hundred common carp fish with an average weight of 12.33 ± 0.93 g were stocked in four treatments (triplicates) for 60 days. The experimental treatments contained Sanyar commercial prebiotics in 100 g of food, which included P1 (1 ml prebiotic liquid), P2 (0.1 g prebiotic powder), P3 (0.5 ml liquid and 0.05 g powder), and treatment C (control treatment without any additives). At the end of the experimental period, the fish were exposed to acute toxicity of Cu (0.1 m/l) for 96 hours. Gill, kidney, and liver tissue samples were collected and evaluated after 96 hours. According to the results obtained, there were significant differences in specific growth rate (SGR) and final weight ( p < 0.05). The lowest feed conversion ratio (FCR) was observed in the Sanyar treatments (1.56 ± 0.37), which had a significant difference from the control treatment (1.85 ± 0.35) ( p < 0.05). The results showed that immunity indices such as lysozyme, cortisol, and ACH50 increased in the experimental treatments compared to the control treatment ( p < 0.05). The highest and lowest lysozyme activities were observed in P2 (16.35 ± 0.57) and control treatments (13.15 ± 1.00), respectively ( p < 0.05). Generally, no significant difference was observed between growth and nutrition indices in Sanyar treatments ( p < 0.05). Symptoms of kidney, liver, and gill tissue damage were reported from mild (hyperemia and infiltration of inflammatory cells) to severe (hemorrhage and necrosis). The lowest severity of tissue damage was observed in the treatments fed with Sanyar food supplement. In general, the results of this study showed that the addition of Sanyar prebiotic to the diet of common carp improves the growth indicators and immune response and can also be beneficial in increasing fish resistance to copper toxicity.

Oxidative stress, gene expression and histopathology of cultured gilthead sea bream (Sparus aurata) naturally co-infected with Ergasilus sieboldi and Vibrio alginolyticus

BackgroundParasitic and bacterial co-infections have been associated with increasing fish mortalities and severe economic losses in aquaculture through the past three decades. The aim of this study was to evaluate the oxidative stress, histopathology, and immune gene expression profile of gilthead sea bream (Sparus aurata) co-infected with Ergasilus sieboldi and Vibrio alginolyticus.ResultsVibrio alginolyticus and Ergasilus sieboldi were identified using 16 S rRNA and 28 S rRNA sequencing, respectively. The collagenase virulence gene was found in all Vibrio alginolyticus isolates, and the multiple antimicrobial resistance index ranged from 0.286 to 0.857. Oxidant-antioxidant parameters in the gills, skin, and muscles of naturally infected fish revealed increased lipid peroxidation levels and a decrease in catalase and glutathione antioxidant activities. Moreover, naturally co-infected gilthead sea bream exhibited substantial up-regulation of il-1β, tnf-α, and cyp1a1. Ergasilus sieboldi encircled gill lamellae with its second antennae, exhibited severe gill architectural deformation with extensive eosinophilic granular cell infiltration. Vibrio alginolyticus infection caused skin and muscle necrosis in gilthead sea bream.ConclusionThis study described some details about the gill, skin and muscle tissue defense mechanisms of gilthead sea bream against Ergasilus sieboldi and Vibrio alginolyticus co-infections. The prevalence of co-infections was 100%, and no resistant fish were detected. These co-infections imbalance the health status of the fish by hampering the oxidant-antioxidant mechanisms and proinflammatory/inflammatory immune genes to a more detrimental side. Our results suggest that simultaneous screening for bacterial and parasitic pathogens should be considered.

Physiological and histopathological effects of polystyrene nanoparticles on the filter-feeding fish Hypophthalmichthys molitrix

Excessive use of plastics in daily life is causing plastic pollution in aquatic environment and threatening the aquatic life. Therefore, research on the plastic pollution in aquatic environment is crucial to understand its impact and develop effective solution for safeguarding aquatic life and ecosystem. The current study investigated the effects of water borne polystyrene nanoparticles (PS-NPs) on hemato-immunological indices, serum metabolic enzymes, gills, and liver antioxidant parameters, plasma cortisol level and histopathological changes in liver and gill tissues of the widely distributed fish Hypophthalmichthys molitrix. The fingerlings of H. molitrix were exposed to different concentrations (T1–0.5, T2–1.0, and T3–2.0 mg/L) of PS-NPs respectively for 15 days consecutively. Our results indicated the dose dependent negative effects of PS-NPs on the physiology and histopathology of H. molitrix. Immuno-hematological indices showed significant increase in WBCs count, phagocytic activity, and lysozyme activity, while decreased RBC count, Hct%, Hb level, total proteins, IgM, and respiratory burst activity were observed. The levels of antioxidant enzymes like SOD, CAT and POD showed the decreasing trends while metabolic enzymes (AST, ALT, ALP and LDH), LPO, ROS activities and relative expressions of SOD1, CAT, HIF1-α and HSP-70 genes increased with increased concentrations of PS-NPs. Moreover, blood glucose and cortisol levels also showed significant increasing trends with dose dependent manner. Histopathological examination indicated moderate to severe changes in the gills and liver tissues of the group treated with 2.0 mg/L of PS-NPs. Overall, the results showed the deleterious effects of PS-NPs on physiology, immunity, metabolism, and gene expressions of H. molitrix. It is concluded that particulate plastic pollution has deleterious effects on filter feeding fish, which might affect human health through food chain and particulate chemical toxicity.

Environmental monitoring: Tobara fish as bioindicators of heavy metal pollution in a coastal ecosystem

This study aims to evaluate the liver, gill, and muscle tissue heavy metal accumulation of the thin lip mullet (Chelon ramada) from Ain Ziana Lagoon, Benghazi. The heavy metals included zinc, copper, lead, and manganese. Between September 2021 and August 2022, specimens were collected on a monthly basis. They were identified using DNA barcoding, namely the CO1 gene, which is associated with the sequence that is BankIt in the NCBI gene bank (accession number OR533708). The research tracked the lagoon's physicochemical characteristics, finding that heavy metal concentrations spiked in the summer and that water temperature, pH, and salinity varied throughout the year. Except for copper in the winter, lead, manganese, and copper levels were all above acceptable limits, according to a comparison with EPA (2005) regulations. On the other hand, zinc levels were under these limitations. The amounts of all metals in the sediment regularly exceeded the limits set by the EPA. Zinc and manganese levels in fish tissues were within the approved ranges according to WHO and FAO standards but lead and manganese levels were far higher than allowed, indicating possible pollution from sewage or industrial sources. There were noticeable seasonal patterns in bioaccumulation, especially during the warmer months, but manganese did not exhibit a distinct pattern. Also noted that the thin lip mullet's mineral absorption and release capacities varied with the different seasons and tissues. Lastly, the Metal Pollution Index (MPI) showed that there was a larger possibility for bioaccumulation in the liver, gill, and muscle during the study period.

The potential mechanism of concentrated mannan-oligosaccharide promoting goldfish’s (Carassius auratus Linnaeus) resistance to Ichthyophthirius multifiliis invasion

Because of the low host specificity, Ichthyophthirius multifiliis (Ich) can widely cause white spot disease in aquatic animals, which is extremely difficult to treat. Prior research has demonstrated a considerable impact of concentrated mannan-oligosaccharide (cMOS) on the prevention of white spot disease in goldfish, but the specific mechanism is still unknown. In this study, transcriptome sequencing, histological analysis, immunofluorescence analysis, phagocytosis activity assay and qRT-PCR assay were used to systematically reveal the potential mechanism of cMOS in supporting the resistance of goldfish (Carrasius auratus) to Ich invasion. According to the transcriptome analysis, the gill tissue of goldfish receiving the cMOS diet showed greater expression of mannose-receptor (MRC) related genes, higher phagocytosis activity, up-regulated expression of phagocytosis-related genes and inflammatory-related genes compared with the control, indicating that cMOS can have an effect on phagocytosis and non-specific immunity of goldfish. After the Ich challenge, transcriptome analysis revealed that cMOS fed goldfish displayed a higher level of phagocytic response, whereas non-cMOS fed goldfish displayed a greater inflammatory reaction. Besides, after Ich infection, cMOS-fed goldfish displayed greater phagocytosis activity, a stronger MRC positive signal, higher expression of genes associated with phagocytosis (ABCB2, C3, MRC), and lower expression of genes associated with inflammation (IL-1β, IL-17, IL-8, TNF-α, NFKB). In conclusion, our experimental results suggest that cMOS may support phagocytosis by binding to MRC on the macrophage cell membrane and change the non-specific immunity of goldfish by stimulating cytokine expression. The results of this study provide new insights for the mechanism of cMOS on parasitic infection, and also suggest phagocytosis-related pathways may be potential targets for prevention of Ich infection.

Epigenetic variation mediated by lncRNAs accounts for adaptive genomic differentiation of the endemic blue mussel Mytiluschilensis

Epigenetic variation affects gene expression without altering the underlying DNA sequence of genes controlling ecologically relevant phenotypes through different mechanisms, one of which is long non-coding RNAs (lncRNAs). This study identified and evaluated the gene expression of lncRNAs in the gill and mantle tissues of Mytilus chilensis individuals from two ecologically different sites: Cochamó (41°S) and Yaldad (43°S), southern Chile, both impacted by climatic-related conditions and by mussel farming given their use as seedbeds. Sequences identified as lncRNAs exhibited tissue-specific differences, mapping to 3.54 % of the gill transcriptome and 1.96 % of the mantle transcriptome, representing an average of 2.76 % of the whole transcriptome. Using a high fold change value (≥|100|), we identified 43 and 47 differentially expressed lncRNAs (DE-lncRNAs) in the gill and mantle tissue of individuals sampled from Cochamó and 21 and 17 in the gill and mantle tissue of individuals sampled from Yaldad. Location-specific DE-lncRNAs were also detected in Cochamó (65) and Yaldad (94) samples. Via analysis of the differential expression of neighboring protein-coding genes, we identified enriched GO terms related to metabolic, genetic, and environmental information processing and immune system functions, reflecting how the impact of local ecological conditions may influence the M. chilensis (epi)genome expression. These DE-lncRNAs represent complementary biomarkers to DNA sequence variation for maintaining adaptive differences and phenotypic plasticity to cope with natural and human-driven perturbations.

Effects of cadmium exposure on tissue structure, antioxidant enzyme activity, serum biochemical indices and gene expression in the liver of juvenile largemouth bass (Micropterus salmoides)

This study aimed to understand the effect of various levels of waterborne cadmium exposure and associated integrated response in largemouth bass (Micropterus salmoides). The experimental fish were randomly divided into 4 groups: Group H (high concentration group): 0.25 mg/L of water (100% of the LC50); Group M (medium concentration group): 0.01 mg/L of water (50% of the LC50); group L (low concentration group): 0.05 mg/L of water (12.5% of the LC50) and group C (control). Experimental fish in group C (control group) were cultured in cadmium (Cd)-free tap water. After 28 days of Cd exposure, the gill and liver tissues were collected for histological analysis and antioxidant enzyme activities assay. Serum biochemical indices and the expression levels of HSP70, HSP90, Cyp1a, and MT in the liver were assayed. Results indicated Cd exposure in group H could significantly damage the gill and liver. The SOD activity of gill and liver exhibited an increasing trend with Cd concentrations increasing, and SOD activities increased significantly in group M compared to that of group C. Still, SOD activity significantly decreased in group H. MDA content increased significantly in both the gill and liver, while T-AOC activities were not significantly different in both the gill and liver. By comparison with group C, the activities of ALT and AST in serum were significantly increased in group M and group H; the contents of ALB and TP significantly decreased in group M and group H except for the content slightly increased in the group L; the contents of GLU, TG, and TC did not show significant changes in the group L and the group M, but increased significantly in the group H. The expression levels of HSP70 and HSP90 in the liver exhibited the highest level in group M, whereas the expression levels of MT and Cyp1a were highest in groups H and L, respectively. Our results are intended to provide a reference basis for the safety risk evaluation of Cd and healthy fish farming.

CBFA2T3 affects red blood phenotype in the blood clam Tegillarca granosa by regulating hemocyte proliferation

The red blood phenotype of blood clam Tegillarca granosa, is tightly linked to its health conditions and nutritional benefits, making it an economically important trait. Despite its significance, the molecular regulatory mechanisms responsible for red blood phenotype variation in blood clams still poorly understood. Our previous study shows that hemocyte proliferation may affect hemoglobin concentration (HGC) and cause the red blood phenotype variation in T. granosa. Thus, we defined total hemocyte counts (THC) and HGC as red blood-related traits. In this research, we discovered that blood clams with higher THC exhibited elevated HGC and a darker blood color. To gain insights into the genes associated with THC in T. granosa, we conducted RNA-Seq analysis. Our transcriptome analysis identified 682 genes exclusively highly expressed in high THC clams (HTHC:THC ≥ 15.5 × 104 cells/mL), and 709 genes highly expressed in low THC clams (LTHC:THC ≤ 6.5 × 104 cells/mL). Furthermore, the weighted gene co-expression network analysis (WGCNA) revealed that the grey60 module exhibited significant positive correlations with THC and HGC, implying an association of this module with the red-blood phenotype. Subsequently, the red blood-related module exhibited a significant positive correlation with gill tissue, providing an alternative perspective to support the hypothesis that gills serve as the primary hematopoietic organ in T. granosa. By employing differential expression analysis and WGCNA, CBFA2T3, TAL1, and FLI1 are potentially key genes involved in the regulation of hemocyte proliferation and differentiation. RNA interference of CBFA2T3 gene led to a remarkable decrease in HGC and THC in T. granosa, resulting in a lighter blood color. EdU staining further confirmed the decrease of cell proliferation activity in the gills of T. granosa after knockdown of CBFA2T3. This study enhances our apprehending of the molecular mechanisms in red blood phenotype variation in T. granosa, and potential contributes to the selection breeding of high THC blood clams.

Studies on Histopathological Alterations in the Brain and Gill, of <i>Cyprinus carpio</i> Exposed to the Insecticide Afidopyropen

The histopathology of the brain and gill tissues of the fish Cyprinus carpio following exposure to afidopyropen was determined by light microscopy. This particular carp species is one of the most prevalent in India. Afidopyropen (0.2 mg/L) was administered to fish for 1, 10, 20, and 30 days as part of an experiment. The tissues in the control group were found healthy. The abnormalities in the brain were Neural Degeneration (ND) Pyknotic Neuron (PN) Necrotic Internal Granule Cells (NIGC) Demyelination (DM). In gill tissues exposed to afidopyropen, hyperplasia, telangiectasia, epithelial separation, and total destruction of lamellae were seen. In the current study, afidopyropen damaged the organs, indicating its potential for harm. There were no sudden histological changes in one day-exposed group of the fishes. It could be due to healthy fish’s strong and quick adaptation capacity. The severity of stress and the associated histological changes would likely increase over time as the exposure to afidopyropen continues. However, prolonged exposure to the toxicant extremely affects the fish physiology leading to the form of above said pathological lesions.

Assessment of Genotoxicity and Histological Changes in the Tissue of Liver, Kidney and Gills Induced by Synthetic Hormone 17 A - Ethinylestradiol (EE2) in Fish, Channa Punctatus (Bloch. 1793)

The synthetic hormone 17α-ethinylestradiol (EE2) is often used as medicine for people, animals, and aquaculture activities. It enters the aquatic environment mostly via sewage treatment facilities.

Differential Toxicity Responses between Hepatopancreas and Gills in Litopenaeus vannamei under Chronic Ammonia-N Exposure.

Ammonia nitrogen is one of the main toxic substances in aquatic cultivation environments. Chronic exposure to excessive amounts of ammonia-N creates toxic consequences, retarding the growth of aquatic organisms. This study investigated the growth performance, morphological and physiological alterations, and transcriptome changes in the hepatopancreas and gills of white shrimp Litopenaeus vannamei. The results showed that there was no significant difference in the survival rate (p > 0.05), whereas growth performance was reduced significantly in the treated groups compared to the control groups (p < 0.05). Significant structural damage and vacuolation occurred in hepatopancreas and gill tissues in the treated groups. Superoxide dismutase (SOD) activity and Na+/K+-ATPase content were significantly increased by chronic ammonia-N exposure in the two tissue groups. In addition, catalase (CAT) activity and malondialdehyde (MDA) levels were significantly altered in the hepatopancreas groups (p < 0.05), whereas no differences were observed in the gill groups (p > 0.05). There were 890 and 1572 differentially expressed genes identified in the hepatopancreas (treated versus control groups) and gills (treated versus control groups), respectively, of L. vannamei under chronic ammonia-N exposure. Functional enrichment analysis revealed associations with oxidative stress, protein synthesis, lipid metabolism, and different serine proteases. The gills maintained cellular homeostasis mainly through high expression of cytoskeleton and transcription genes, whereas the hepatopancreas down-regulated related genes in the ribosome, proteasome, and spliceosome pathways. These genes and pathways are important in the biosynthesis and transformation of living organisms. In addition, both tissues maintained organismal growth primarily through lipid metabolism, which may serve as an effective strategy for ammonia-N resistance in L. vannamei. These results provided a new perspective in understanding the mechanisms of ammonia-N resistance in crustaceans.

Metabolic adaptation of the clam Ruditapes philippinarum during air exposure and the positive effects of sodium nitroprusside pretreatment.

The Manila clam (Ruditapes philippinarum), as one of the shellfish living in the intertidal zone, is known for its strong ability to withstand air exposure. Sodium nitroprusside (SNP), a donor of nitric oxide (NO), has been shown to be useful for antioxidant and immune regulation in aquatic animals. In this study, an untargeted metabolomics (LC-MS/MS) technique was employed for the first time in Manila clam to analyze the metabolic and histological impacts after air exposure and the positive effects of SNP pretreatment. During air exposure, a significant increase in taurine, L-glutamate, and several polyunsaturated fatty acids in clams was detected, which indicates that clams may experience inflammatory reactions, oxidative stress, and an increase in blood ammonia content. When clams were exposed to SNP for 6h, arginine, spermine, L-glutamic acid, and glutathione content were all upregulated, indicating that the SNP exposure induced NO production and improved antioxidant capacity in clams. When the clams were exposed to air after SNP pretreatment, there were no significant differences in the levels of taurine, L-glutamate, or aliphatic acids between the experimental and control groups. Gill tissue was more severely damaged in clams directly exposed to air than in those that experienced air exposure after SNP pretreatment, especially in clams exposed to air for a long time (72h). Both metabolomics and tissue section structure indicated that SNP pretreatment decreased the stress responses caused by air exposure in R. philippinarum. These findings provided fresh insights and a theoretical foundation for understanding the tolerance to air exposure and physiological functions of SNP (or NO) in R. philippinarum.

Effects of vitamin C combined with sodium alginate on serum biochemistry, oxidative stress, gill tissue morphology, and muscle quality of pearl gentian grouper during waterless transport.

This research examined the effects of sodium alginate (SA) and vitamin C (Vc) soaking of pearl gentian grouper before waterless transportation from the perspectives of serum parameters, oxidative stress, muscle quality, and gill tissue morphology. After the fish reached semi-dormancy with a cooling rate of 3°C/h, fish (420 ± 25g) were distributed to 4 treatments as follows: S1 group (50mg/L Vc and 0.1% SA were added), S2 group (50mg/L Vc and 0.3% SA were added), S3 group (50mg/L Vc and 0.5% SA were added), and control group (without soaking in protective fluid). After oxygenated packaging, samples were taken at 0, 8, and 16h of waterless transportation and 12h after rehydration, respectively. It was found that after 16h of waterless transport, compared with the control group, cortisol, glucose, blood urea nitrogen (BUN), uric acid (UA), creatinine (CREA), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and malondialdehyde (MDA) levels were significantly decreased (p < 0.05), while albumin, lysozyme (LZM), muscle pH, and total free amino acid (TFAA) contents were significantly elevated (p < 0.05) in the S3 group. Moreover, by gill tissue microscopy, it was found that the protective solution of group S3 did not cause serious deleterious morphological changes to the gill epithelium. The results showed that the grouper was soaked by protective fluid before waterless could maintain surface moisture, reduce gill and kidney function and oxidative stress damage, and maintain the stability of muscle quality. This study provides a novel transportation method for waterless preservation, which helps to reduce transportation costs and improve transportation efficiency.

The effects of bisphenol S exposure on the growth, physiological and biochemical indices, and ecdysteroid receptor gene expression in red swamp crayfish, Procambarus clarkii

The experiment was conducted to investigate the effects of Bisphenol S (BPS) on growth, physiological and biochemical indices, and the expression of ecdysteroid receptor (ECR) of the red swamp crayfish (Procambarus clarkii). The gene encoding ECR was isolated from red swamp crayfish by homologous cloning and rapid amplification of cDNA ends (RACE). The ECR transcripts were 1757 bp long and encoded proteins of 576 amino acids. The quantitative real-time PCR (qRT-PCR) analysis showed that the ECR gene was expressed in various tissues under normal conditions, and the highest level was observed in the ovary and the lowest level was observed in the muscle (P < 0.05). Then, the experiment was designed with four different BPS concentrations (0, 1, 10, and 100 μg/L), BPS exposure for 14 days, three parallel groups, and a total of 240 red swamp crayfish. At 100 μg/L BPS, the survival rate, weight gain rate, and relative length rate were decreased significantly (P < 0.05). Malonaldehyde (MDA) content reached the highest level at 100 μg/L BPS. When BPS concentration was higher than 10 μg/L, the activities of superoxide dismutase (SOD) and catalase (CAT) were significantly lower than those of the control group (P < 0.05). The expression levels of the ECR gene in ovary, intestinal, gill, and hepatopancreas tissues were significantly increased after BPS exposure (P < 0.05). The ECR gene expression in ovaries and Y-organs was significantly higher than other groups in 10 μg/L BPS (P < 0.05). The expressions of the tumor necrosis factor -α (TNF-α) and interleukin-6 (IL-6) genes in the hepatopancreas gradually increased, and the highest expression was observed exposed in 100 μg/L BPS (P < 0.05). This research will provide novel insights into the health risk assessment of BPS in aquatic organisms.