Fish Physiology and Biochemistry最新文献

The study aims to investigate the synergistic antioxidant effects of the phenolics present in Mentha piperita (MP) against arsenic trioxide-induced oxidative stress, biochemical alteration, and cyto-genotoxicity in the fish, Channa punctatus. The phenolic composition of MP estimated by HPLC-PDA analysis reveals the presence of phenolics, viz., ascorbic acid (Rt = 2.763 min.), rutin (Rt = 12.597 min.), caffeic acid (Rt = 18.304 min.), quercetin (Rt = 26.731 min.), luteolin (Rt = 42.709 min.), and hesperetin (Rt = 49.525 min.). The experimental setup consists of four groups (G1-G4) with a density of 12 fish in each. The fishes in G1 served as the control group, whereas the fishes in G2 were exposed to 81.73 mg/L of As₂O₃. Fish in group G3 were subjected to 8 mg/L MP, whereas those in group G4 were treated to 8 mg/L MP plus 81.73 mg/L As₂O₃. The result showed a significantly (p < 0.05) increased GOT and GPT level, increased oxidative stress markers, SOD and CAT, and induction in cyto-genotoxic markers, viz., disintegrated nucleus (DN), microcyte (MC), echinocyte (EC), and nucleoplasmic bridges (NpBs). A significant (p < 0.05) decreased GSH level in the arsenic-exposed group for all exposure periods was observed. However, in G4, all parameters reduced significantly (p < 0.05) more than in G2. The results suggest that the phenolics present in MP are synergistically able to reduce arsenic-induced oxidative damages by improving antioxidant defence, thus improving fish health status.

This study examined how European seabass, Dicentrarchus labrax, juveniles are affected by heat stress in several ways, including growth biometrics, stress indicators, oxidative stress biomarkers, and histopathological changes. Our research aims to gain a better understanding of the impact of thermal stress on these parameters. Hence, European seabass juveniles (30-32 g) were exposed to temperatures of 20 °C, 23 °C, 26 °C, 29 °C, and 31 °C using a 28-day bioassay. It was noted that the fish showed better performance indices at 23 °C and 26 °C. However, fish reared at 20 °C showed intermediate growth, while the fish reared at 31 °C displayed poor performance with low survival rates. As the water temperature increased from 20 to 31 °C, the levels of glucose, cortisol, aspartate aminotransferase, and alanine aminotransferase in the fish blood also increased, suggesting that the fish were under stress. Furthermore, activities of superoxide dismutase (SOD) and catalase (CAT), as well as levels of malondialdehyde, increased significantly (P < 0.05) with the rise in the rearing temperature, particularly at 31 °C. This suggested that European seabass juveniles experienced oxidative stress. Additionally, the mRNA expression of SOD and CAT genes was upregulated at 31 °C compared to those reared at 23-26 °C. This high upregulation of both genes led to an increase in the secretion of SOD and CAT. Juveniles of European seabass raised in 31 °C for 28 days showed significant damage in the histological structure of their kidney, liver, and gills. In addition to fusion and blood congestion of secondary lamellae, the fish in this treatment (31 °C) displayed edema, epithelial lifting, and blood congestion of the gill epithelium. After 28 days, fish cultivated at 31 °C had sinusoid dilatation, hyperemia, and nuclear hypertrophy in their liver tissues. Furthermore, hyperemia, tubular necrosis, and severe glomerular congestion were observed in fish raised in water temperatures as high as 31 °C for 28 days. This study recommends farming European seabass at 23 °C and 26 °C, which were the optimum temperatures. By global warming due to climatic changes, water temperature may reach up to 31 °C or more, which will cause adverse effects on fish performance and increase the oxidative stress.

This study examined how combining curry leaf (Murraya koenigii) and marigold leaf (Tagetes erecta) extracts affects immune response and disease resistance in Labeo rohita (rohu) fish against Saprolegnia parasitica infection. We conducted a 74-day trial using 360 juvenile rohu divided into four treatment groups: control (T0), curry leaf extract (T1), marigold leaf extract (T2), and combined extracts (T3). The trial consisted of a 60-day feeding period followed by a 14-day pathogen challenge test. The combined extract treatment (T3) demonstrated superior results across all measured parameters. Fish in T3 showed significantly enhanced hematological values, with the highest hemoglobin content (9.4 ± 0.5 g/dL) and total leukocyte count (41.3 ± 2.5 × 103/μL) post-challenge. Immunological parameters were markedly elevated in T3, with serum immunoglobulin levels reaching 22.7 ± 1.3 mg/mL after pathogen exposure. Importantly, liver enzyme levels remained stable across all treatments, indicating the safety of the extracts. Disease resistance metrics in T3 were notably superior, with the highest survival rate (86.7%), minimal lesion severity (1.2 ± 0.2 on a 4-point scale), and lowest fungal load (1.8 × 103 ± 0.3 × 103 gene copies/mg tissue) following pathogen challenge. The enhanced performance of the combined treatment suggests a synergistic effect, potentially activating multiple immune pathways simultaneously. These findings demonstrate that the combination of curry and marigold leaf extracts offers a promising natural approach for enhancing disease resistance in aquaculture.

Contamination of the aquatic bodies with pesticides is a serious issue that hinders the aquaculture industry worldwide. Preventing aquatic pollution is a challenge, and finding eco-friendly strategies could help to overcome such a problem. Herein, we studied the antagonistic potential of dietary fortification of white poplar (Populus alba; PA) leaf powder against chronic hexaflumuron (HX) toxicity in Nile tilapia (Oreochromis niloticus). Fish (n = 200; 36.20 ± 1.55 g) were eventually grouped into four groups with five replicates and kept for 60 days. The C (control) and PA groups were fed basal diets fortified with 0 and 6 g PA/kg diet, respectively, without toxicant exposure. Additionally, the HX and PA + HX groups were exposed to 1/10 of 96-h lethal concentration 50 (96-h LC₅₀) of HX (0.72 mg/L) and given the same diets as those of the C and PA groups, respectively. The biochemical, immune-antioxidant, survival, splenic gene expression, and tissue microstructure were assessed at the end of the exposure time. The outcomes of this research showed that exposure to HX resulted in biochemical disorders (elevated blood glucose, cortisol, alanine aminotransferase, aspartate aminotransferase, and creatinine) in Nile tilapia. Immune suppression (lowered complement 3 and immunoglobulin M) and oxidative stress (lowered superoxide dismutase and catalase activity and higher malondialdehyde) were consequences of HX toxicity. The splenic expression of nuclear factor-kappa β65, kelch-like ECH-associated protein 1, and heme oxygenase-1 was down-regulated by HX exposure. Various pathological changes were noted as consequences of HX exposure in the liver, kidney, and spleen tissues. By feeding on the PA diet, the fish survivability was increased (90%) compared to the non-fed group (76%). Additionally, the biochemical disorders were modulated, and immune responses were enhanced due to PA feeding. Amelioration of the oxidative stress condition (by improving the antioxidant enzyme activity and lowering malondialdehyde) and the immune gene expression were noticed when the HX-exposed Nile tilapia were fed on the PA diet. A noticeable soothing effect was noticed by feeding on the PA diet against the pathological changes in the Nile tilapia tissues. Overall, feeding on a 6 g PA/kg diet ameliorates the detrimental consequences of HX toxicity in Nile tilapia.

Alkaline stress is a major concern in aquaculture that badly affects the aquatic species' health and hemostasis. This research investigated the effect of carbonate alkalinity exposure on the gills and kidney organs as important organs for hemostasis, as well as the ameliorative role of camel protein hydrolysates (CPH) as dietary additives against alkaline stress detrimental impacts in Nile tilapia (Oreochromis niloticus). The fish (n = 160) were divided into four groups (G1, G2, G3, and G4), with the control (G1) fed a basal diet, while G2 was fed a basal diet supplemented with 75 g CPH/kg and was reared in freshwater (carbonate alkalinity of 1.4 µmol/L, pH = 7.19). The G3 and G4 were reared in alkaline water (carbonate alkalinity of 23.8 µmol/L, pH = 8.65) and fed the same diets as G1 and G2 for 30 days, respectively. The fish were stocked under a water temperature of 26.4 ± 1.5 °C, and the diets were introduced to the fish three times daily at a rate of 4% of their body weight. The results of this research showed that alkaline exposure increased kidney function parameters (creatinine, urea, and uric acid), glucose, and cortisol levels in the exposed fish. Alkaline exposure reduced the blood electrolytes level (calcium, magnesium, sodium, potassium, and chloride) and branchial antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase, and reduced glutathione) and elevated malondialdehyde level in the exposed fish. Significant downregulation of the branchial expression of Na⁺/K⁺ ATPase α-3 subunit (0.17-fold), calcium/calmodulin-dependant protein kinase 1 β (0.23 fold), chloride channel protein 2 (0.38-fold), solute carrier family 12 a 2 (0.33-fold), and solute carrier family 4 a 4 (0.21-fold) was in the fish-reared under carbonate alkalinity stress. Alkaline exposure induced severe histopathological changes in the gills and kidney tissue architecture including inflammatory, circulatory, degenerative, and progressive responses. Supplementation of the Nile tilapia diet with 75 g CPH/kg ameliorated renal function and balanced the blood electrolytes, glucose, and cortisol levels in the alkaline-exposed fish. Modulation of the branchial gene expression profile and improving the gills and kidney microstructure were consequences of feeding on CPH diets during alkaline stress situations. Overall, fortifying the Nile tilapia diets with 75 g CPH/kg helps the fish restore their hemostasis and metabolic status during alkaline stress exposure which enables the sustainable culture of this species in such conditions.

Fish are facing compromised health with mass mortality due to the decreased water quality of aquatic bodies. The brain, a complex body organ that controls whole body physiology, is influenced first by any kind of water fluctuations, and by keeping it relaxed and nourished, fish health can be improved. Among freshwater fish, catfish Heteropneustes fossilis has importance not only as a rich nutrient source but also due to medicinal significance. This study evaluated the impact of pyrimidine, a well-known organic compound with several therapeutic properties, on the cerebral health of the freshwater catfish H. fossilis as a bioremediation of aquatic environmental threats. In experiments, to get an effective concentration of pyrimidine, fish were incubated with different doses of pyrimidine (10 fg/mL-1 mg/mL) for 24 h, and brain histotexture and fish survival were recorded. As per the results of the previous experiment, an effective concentration of pyrimidine (10 pg/mL) was given for different durations (1-, 5- and 21-day incubation with pyrimidine and recovery; after 21-day treatment in only water for 7 days) along with the control group. Results exhibited that the level of cerebral antioxidant enzymes (catalase, superoxide dismutase, peroxidase) and lipid peroxidation were significantly lower, and macromolecules (carbohydrate, protein and lipid) were increased in pyrimidine-treated fish with duration of pyrimidine treatment as compared to the control group. Histo-neurological analysis of the brain with haematoxylin-eosin and cresyl violet revealed that an effective, nonlethal concentration of pyrimidine supported overall neuronal health without any histopathological changes. However, in the recovery experimental group, results showed reverting of pyrimidine induced positive changes in antioxidative enzyme and energy biomolecule levels, supporting the non-bio-accumulative nature of pyrimidine. However, microphotographs revealed that the neuronal quantity (cresyl violet) and cellular histotexture (haematoxylin-eosin) improvement due to pyrimidine were sustained in the recovery group. The results of this study suggested that effective concentration of pyrimidine improved the brain health of H. fossilis in a duration-dependent manner compared to control fish due to increased metabolism by upregulating energy macromolecule and cellular-neuronal texture along with downregulation of antioxidative stress.

As an environmental estrogen biomarker, the yolk precursor, vitellogenin (Vtg) is widely used in the assessment of estrogen pollution in aquatic environment. Currently, the detection of Vtg in plasma is mainly achieved by enzyme-linked immunosorbent assay (ELISA) method based on Vtg antibodies. However, due to differences in the immunological epitopes of Vtg from various species, Vtg antibodies have low universality. Therefore, identifying a universal antigenic epitopes of Vtg from multiple fish species and designing a tools that can be applied in the field can promote the use of Vtg in monitoring estrogenic contamination in aquatic environments. Bioinformatics analysis of the Vtg of Bostrichthys sinensis revealed that the protein is highly conserved in structure. The results of PCR showed that the amino acid sequence encoded by the BsVg819 gene fragment from the Vtg gene of Bostrichthys sinensis could have more than 97% similarity with the amino acid sequences of the PCR products of ten fish species. Development of a colloidal gold immunochromatographic test strip using recombinant proteins was expressed in BsVg819 gene fragments. The test strip was able to detect Vtg in the plasma of untreated female Bostrichthys sinensis and ten different female fish species. Vtg in the plasma of juvenile Bostrichthys sinensis treated with estrogen is elevated and can be detected by test strips. The results show that the test strips have good usability. Compared to ELISA, the strip is prospective for field applications. It provides a portable tool for future rapid detection of estrogenic contamination in the field.

Recent studies have demonstrated that the fish liver protein fraction extract obtained by gel filtration exhibits nitric oxide synthase (NOS)-independent NO synthase from nitrates and nitrites. This activity was attributed to the molybdenum enzymes (Mo-enzymes) group which was already demonstrated in mammals. However, the evidence that NOS-independent NO synthase activity can be classified as a fish Mo-enzyme has been poorly demonstrated. In mammals, Mo-enzymes NOS-independent NO synthase activity occurs at the molybdenum center. We studied the ability of molybdenum cofactor (Mo-co) isolated from the protein fraction of fish liver extract to restore the NADPH-nitrate reductase (NADPH-NR) activity from Neurospora crassa nit-1. Our results demonstrated that Mo-co from the extract from fish liver was able to recover NADPH-NR activity in the extract of N. crassa nit-1, thereby possessing the ability to reduce nitrogen compounds. However, the oxidation of Mo-co from fish liver destabilizes molybdenum, leading to its inactivation. However, the results obtained under anaerobic conditions with dithionite indicate that Mo remains bound to Mo-co under highly reducing conditions. This may also indicate that the availability of Mo is not the sole factor affecting the activity of Mo-enzymes, also oxygen content after the synthesis of mature Mo-co may play a role in cofactor inactivation.

Dissolved oxygen (DO) is necessary for fish survival and growth. This study investigated the hypoxia tolerance, hematological indexes, hepatic antioxidant capacity, and liver and gill morphological alternation of fat greenling during hypoxia stress. Changes in hematological parameters (cortisol, glucose, lactic acid, hemoglobin [Hb], hematocrit [Hct], and white blood cell [WBC], and red blood cell [RBC] numbers), hepatic antioxidant enzymes (superoxide dismutase [SOD], glutathione peroxidase [GSH-Px], catalase [CAT]), aminotransferase (AST), alanine aminotransferase (ALT) activities, and malondialdehyde (MDA) contents, and the histology of the liver and gill were evaluated under hypoxia stress and reoxygenation. Results showed that the DO at critical oxygen tension (Pcrit) and loss of equilibrium (LOE) were 3.10 ± 0.17 mg/L and 1.90 ± 0.11 mg/L, respectively. Hypoxia stress significantly stimulated the respiratory frequency rate, Hb and Hct levels, and RBC numbers; the highest values were observed at Pcrit and LOE, respectively. Serum glucose, cortisol and lactic acid contents, and hepatic MDA, AST, ALT, SOD, and CAT activity demonstrated similar results to Hb. However, hepatic GSH-Px activity obtained the highest value at Pcrit and drastically decreased the lowest value at LOE. Moreover, hypoxia stress induced hepatocyte necrosis, vacuolization, and increased hepatocyte apoptosis rate. Lamellar perimeters, length, surface area, and gill surface area manifested results similar to those for respiratory frequency rate, whereas lamellar width and interlamellar distance significantly decreased at Pcrit, LOE, and reoxygenation treatment for 4 h. The above parameters returned to nearly normal levels after reoxygenation treatment for 8 h. These results suggest that fat greenling is a hypoxia-tolerant marine fish that copes with potential hypoxia-induced damage by elevating hematological-related parameters, stimulating hepatic antioxidant capacity, and altering the gill and liver morphology to maintain homeostasis.