Palliative effects of zinc sulfate against the immunosuppressive, hepato- and nephrotoxic impacts of nonylphenol in Nile tilapia (Oreochromis niloticus)

Chronic cypermethrin induced toxicity and molecular fate assessment within common carp (Cyprinus carpio) using multiple biomarkers approach and its novel therapeutic detoxification

Cypermethrin (CYP) is a chemical of emerging concern which has persistent and bioaccumulating impacts as it can be found extensively in freshwater ecosystem and agricultural products. It has exposure risk and toxic effects over human edible fish, as common carp. Four groups were designed for toxicity assessment and detoxification approach: control group (CL), CYP exposure group (CYP), CYP + 10% M. oleifera leaves and 10% M. oleifera seeds (CMO group), 10% M. oleifera leaves and 10% M. oleifera seeds (MO group). Trial period was forty days during which cohort of 240 fish in CYP and CMO group was exposed to 1/5 of 96h LC50 of CYP (0.1612 μg/L). CYP-exposed carp exhibited lower growth parameters, but carp fed with 10% M. oleifera seeds and leaves showed significant improvement in growth rate (SGR, RGR) and weight gain (WG) as compared to the control group. CYP exposure negatively affected haemato-biochemical parameters. Moreover, CYP exposure also led to oxidative stress, damaged immunological parameters, genotoxicity and histopathological damage in liver and intestinal cells. Whereas, M. oleifera supplementation has ameliorated these conditions. Thereby, supplementation with M. oleifera is potential and novel therapeutic detoxication approach for common carp and human health against persistent and bioaccumulating emerging chemicals.

Supplementation of Siberian sturgeon (Acipenser baerii) diet with different zinc sources: effects on growth performance, digestive enzymes activity, hemato-biochemical parameters, antioxidant response and liver histology

An 8-week feeding trial was carried out to examine the effect of different sources of dietary Zn on some physiological responses (performance, digestive enzymes activity, hemato-biochemical parameters, antioxidant status and liver histology) of Siberian sturgeon, Acipenser baerii. For this purpose, fish with an average weight of 100 g ± 5 were randomly allocated into four groups including control, inorganic zinc (Zn-sulfate), organic zinc (Zn-gluconate), and zinc-oxide nanoparticles (ZnO-NPs) at 50 mg Zn kg- 1 feed. Improved growth indices, namely weight gain (WG) and specific growth rate (SGR) and feed conversion ratio (FCR) were observed in fish fed Zn-gluconate supplemented diet (P < 0.0.5). The highest digestive enzymes activity was recorded in fish fed Zn-gluconate supplementation (P < 0.0.5). Hematological indices significantly increased in fish fed diet containing ZnO-NPs (P < 0.0.5). Serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) of fish fed ZnO-NPs contained diet were the highest (P < 0.0.5). The highest serum superoxide dismutase (SOD) and catalase (CAT) enzymes activity were observed in fish fed ZnO-NPs and inorganic/organic Zn contained diets, respectively. While liver tissue SOD and glutathione peroxidase (GPx) enzymes activity Zn were significantly increased in fish fed inorganic/organic Zn supplemented diet (P < 0.0.5). Based on liver histological results, a severe tissue changes such as necrosis and pyknosis were observed in fish fed with Zn-sulfate in comparison to other forms. In conclusion, the data of the present study confirmed that organic Zn (mainly) and nano-Zn (to some extent) could be more efficient Zn sources in Siberian sturgeon.

Nelumbo nucifera synthesized selenium nanoparticles modulate the immune-antioxidants, biochemical indices, and pro/anti-inflammatory cytokines pathways in Oreochromis niloticus infected with Aeromonas veronii

Bacterial infection is considered one of the major issues in fish culturing that results in economic losses. Metal nanoparticles are a cutting-edge and effective disease management and preventive strategy because of their antibacterial ability. In this investigation, the selenium nanoparticles were prepared by a biological method using Nelumbo nucifera leaves extract. The in-vitro antibacterial activity of N. nucifera synthesized selenium nanoparticles (NN-SeNPs) was tested against Aeromonas veronii. A treatment assay was conducted on 210 Oreochromis niloticus (average body weight: 27 ± 2.00 g). A preliminary approach was conducted on 90 fish for determination of the therapeutic concentration of NN-SeNPs which was found to be 4 mg/L. Fish (n = 120) were categorized into four groups for 10 days; G1 (control) and G2 (NN-SeNPs) were non-challenged and treated with 0 and 4 mg/L NN-SeNPs, respectively. While, G3 and G4 were infected with 2 × 106 CFU/mL of A. veronii and treated with 0 and 4 mg/L NN-SeNPs, respectively. NN-SeNPs exhibited an inhibition zone against A. veronii with a diameter of 16 ± 1.25 mm. The A. veronii infection increased the hepato-renal biomarkers (alanine and aspartate aminotransferases and creatinine) than the control group. An oxidative stress was the consequence of A. veronii infection (higher malondialdehyde and hydrogen peroxide levels with lower glutathione peroxidase superoxide, dismutase, and catalase activity). A. veronii infection resulted in lower immunological biomarker values (immunoglobulin M, lysozyme, and complement 3) with higher expression of the inflammatory cytokines (interleukin-1β and tumor necrosis factor-ɑ) as well as lower expression of the anti-inflammatory cytokines (interleukin-10 and transforming growth factor-β). Therapeutic application with 4 mg/L NN-SeNPs prevented the disease progression; and modulated the hepato-renal function disruptions, oxidant-immune dysfunction, as well as the pro/anti-inflammatory cytokines pathway in the A. veronii-infected fish. These findings suggest that NN-SeNPs, employed as a water therapy, can safeguard fish from the harmful effects of A. veronii and serve as a promising antibacterial agent for sustainable aquaculture.

Alpha-lipoic acid suppresses gibberellic acid nephrotoxicity in Nile tilapia (Oreochromis niloticus) via modulating oxidative stress, inflammation, cytokine production, and apoptosis

Globally, gibberellic acid (GA) is one of the extensively used plant growth regulators in agriculture. Yet, there is limited information about their toxicity to fish. Recently, alpha lipoic acid (ALA) has drawn much interest due to its antioxidant properties. This study was planned to determine whether ALA might protect Nile tilapia's kidneys from the toxic effects of GA and the probable underlying mechanisms. Thus, 240 Oreochromis niloticus fish (average initial weight 30.67 ± 0.57) were allocated into four groups received a basal diet or a basal diet supplemented with 600 mg/kg ALA or a basal diet but exposed to a GA (150 mg/L), or ALA-fortified diet and concurrently exposed to GA as previously described. After 60 days, hematological, oxidative stress, lipid peroxidation, stress indices, selected kidney toxic byproducts, histological investigations, and associated gene expression were assessed. Anemia, leukopenia, hypoproteinemia, and elevated kidney function indicators were noticed in the GA-treated group. Additionally, there were detectable cortisol, glucose, 8-OHdG, and MDA increases. However, there was a considerable drop in Cat, Sod, Gpx, GSH, and AChE levels. Structural damage to the kidneys was also identified. In the kidney of fish treated with GA, pro-inflammatory cytokines (tnfα, il-1β), stress, and apoptotic genes (hsp70, pcna, caspase-3, and p53) genes were markedly up-regulated, while anti-oxidative (cat, sod) gene expression was downregulated. Conversely, adding ALA to the diet abolished the GA-induced changes in most of the markers mentioned above. Conclusively, ALA protects against GA-induced hematotoxicity, oxidative damage, and nephrotoxic effects in Nile tilapia fish.

Neurotoxicity of 4-nonylphenol in adult zebrafish: Evaluation of behaviour, oxidative stress parameters and histopathology of brain

Nonylphenol and its derivatives use as plasticizer or additives in manufacturing industries. Effluents originated from industrial areas are being added to soil, ground water, river and marine water intentionally or unintentionally. Complex mixture of these contaminants enter the food chain and produce sub-lethal deleterious effects mainly on nervous and reproductive systems of aquatic animals and human beings. The information pertaining to oxidative stress-mediated alterations in brain of zebrafish would be helpful to understand the toxicity potential of such compounds in aquatic animals. The aim of the present study was to evaluate the behavioural changes, status of oxidative stress markers; sod, cat, and NF-E2-related factor 2 (nrf2) mRNA gene expression profile; and histopathological changes in the brain of adult zebrafish exposed to 4-nonylphenol (4NP) at concentration of 100 and 200 μg/L of water for 21 days. Zebrafish were divided into four groups viz; control (C1), vehicle (C2, ethanol 10 μg/L of water), treatment 1 (T1, 4-NP, 100 μg/L) and treatment 2 (T2, 4-NP, 200 μg/L). Both exposure levels of 4-NP adversely affected the exploratory behaviour of zebrafish and produced anxiety-like symptom. Concentration-dependent reduction in activity of superoxide dismutase and catalase; and glutathione level, with increased level of malondialdehyde recorded in the brain of exposed zebrafish. Gene expression analysis showed down regulation of sod, cat, nrf2 genes in brain of zebrafish from toxicity groups indicating 4-NP induced oxidative stress in brain. However, noticeable histological alterations were not observed in 4-NP exposed brain of zebrafish.

Chitosan neem nanocapsule enhances immunity and disease resistance in nile tilapia (Oreochromis niloticus)

Finding eco-friendly alternatives for antibiotics in treating bacterial diseases affecting the aquaculture sector is essential. Herbal plants are promising alternatives, especially when combined with nanomaterials. Neem (Azadirachta indica) leaves extract was synthesized using a chitosan nanocapsule. Chitosan neem nanocapsule (CNNC) was tested in-vitro and in-vivo against the Aeromonas sobria (A. sobria) challenge in Nile tilapia. A preliminary experiment with 120 Nile tilapia was conducted to determine the therapeutic dose of CNNC, which was established to be 1 mg/L. A treatment study was applied for seven days using 200 fish categorized into four groups (10 fish/replicate: 50 fish/group). The first (control) and second (CNNC) groups were treated with 0 and 1 mg/L CNNC in water without being challenged. The third (A. sobria) and fourth (CNNC + A. sobria) groups were treated with 0 and 1 mg/L CNNC, respectively, and challenged with A. sobria (1 × 107 CFU/mL). Interestingly, CNNC had an in-vitro antibacterial activity against A. sobria; the minimum inhibitory concentration and minimum bactericidal concentration of CNNC against A. sobria were 6.25 and 12.5 mg/mL, respectively. A. sobria challenge caused behavioral alterations, skin hemorrhage, fin rot, and reduced survivability (60%). The infected fish suffered a noticeable elevation in the malondialdehyde level and hepato-renal function markers (aspartate aminotransferase, alanine aminotransferase, and creatinine). Moreover, a clear depletion in the level of the antioxidant and immune indicators (catalase, reduced glutathione, lysozymes, nitric oxide, and complement 3) was obvious in the A. sobria group. Treatment of the A. sobria-challenged fish with 1 mg/L CNNC recovered these parameters and enhanced fish survivability. Overall, CNNC can be used as a new versatile tool at 1 mg/L as a water treatment for combating the A. sobria challenge for sustainable aquaculture production.

Acute mancozeb-fungicide exposure induces neuro-ethology disruption, health disorders, and immune-oxidative dysfunction in Nile tilapia (Oreochromis niloticus)

An acute exposure study of mancozeb (MAZ) fungicide was applied on Oreochromis niloticus for 96-h duration. Three hundred fish (20.50 ± 1.60 g) were assigned into six groups (50 fish/ group; 10 fish/replicate) and exposed to different six concentrations (0, 4, 8, 12, 16, and 20 mg L^-1) of MAZ for 96-h. The Probit analysis program was used to compute the 96-h lethal concentration 50 (96-h LC₅₀) of MAZ. During the exposure duration, the fish's behavior, clinical symptoms, and mortalities were recorded daily. After the exposure period was ended, the hematological, biochemical, immunological, and oxidant/antioxidant parameters were evaluated. The results of this study recorded the 96-h LC₅₀ of MAZ for O. niloticus to be 11.49 mg L^-1. Acute MAZ exposure badly affected the fish's behavior in the form of increased the breath gasping and swimming activity with aggressive mode. The exposed fish showed excessive body hemorrhages and fin rot. The survival rate of the exposed fish to MAZ was 100, 80, 66, 50, 38, and 30% in 0, 4, 8, 12, 16, and 20 mg L^-1 MAZ, respectively. The hematological indices (red blood cell count, hemoglobin, packed cell volume%, and white blood cell count) were significantly decreased by increasing the MAZ exposure concentration (8-20 mg L^-1). The acetylcholine esterase activity and immune indices (lysozyme, nitric oxide, immunoglobulin M, complement 3) were decreased by MAZ exposure (4-20 mg L^-1). Acute MAZ exposure induced hepato-renal dysfunction and elevated stress-related parameter (cortisol) by increasing the MAZ concentration. A significant reduction in the antioxidant parameters (total antioxidant activity, catalase, and superoxide dismutase) with increasing the lipid peroxidation marker (malondialdehyde) was noticed by acute MAZ exposure (4 -20 mg L^-1) in O. niloticus. Based on these outcomes, the MAZ exposure induced toxicity to the fish evident in changes in fish behavior, neurological activity, hepato-renal functioning, and immune-antioxidant responses which suggest physiological disruption.

Nigella sativa seeds mitigate the hepatic histo-architectural and ultrastructural changes induced by 4-nonylphenol in Clarias gariepinus

Due to its prevalence in aquatic environments and potential cytotoxicity, 4-nonylphenol (4-NP) has garnered considerable attention. As a medicinal plant with numerous biological activities, Nigella sativa (black seed or black cumin) seed (NSS) is widely utilized throughout the world. Consequently, this study aimed to examine the potential protective effects of NSS against 4-NP-induced hepatotoxicity in African catfish (Clarias gariepinus). To achieve this objective, 18 fish (351 ± 3 g) were randomly divided into three equal groups for 21 days. The first group serves as a control which did not receive any treatment except the basal diet. The second and third groups were exposed to 4-NP at a dose of 0.1 mg L^-1 of aquarium water and fed a basal diet only or supplemented with 2.5% NSS, respectively. The histological, histochemical, and ultrastructural features of the liver were subsequently evaluated as a damage biomarker of the hepatic tissue. Our results confirmed that 4-NP was a potent hepatotoxic agent, as 4-NP-intoxicated fish exhibited many lesions. Steatohepatitis, ballooning degeneration, sclerosing cholangitis, and coagulative necrosis of melanomacrophagecenters (MMCs) were observed. Hemosiderin, lipofuscin pigments, and proliferation of fibroblasts, kupffer cells, and telocytes were also demonstrated in the livers of 4-NP-intoxicated fish. In addition, decreased glycogen content and increased collagen deposition were observed in the hepatic tissue. Hepatocytes exhibited ultrastructural alterations in the chromatin, rough endoplasmic reticulum, smooth endoplasmic reticulum, mitochondria, lysosomes, and peroxisomes. Co-administration of 2.5% NSS to 4-NP-intoxicated fish significantly reduced these hepatotoxic effects. It nearly preserved the histological, histochemical, and ultrastructural integrity of hepatic tissue.

Toxicity bioassay and sub-lethal effects of profenofos-based insecticide on behavior, biochemical, hematological, and histopathological responses in Grass carp (Ctenopharyngodon idella)

Profenofos (organophosphate) is among the major toxicant polluting freshwater bodies, exerting a significant effect on fish health. The LC50 value of Profenofos (PRO) was resolved in Grass carp (Ctenopharyngodon idella) with average body weight (55.82 ± 5.42 g) and determined the 96 h LC50 value as 7.2 µg/L for the assay. Twenty-one-day exposures to 1.8 µg/ L and 3.6 µg/ L doses were conducted to evaluate the sub-lethal effects, and various toxicological endpoints were assessed on the 1st, 7th, 15th and 21st days of exposure. Acute toxic stress was observed with fish displaying behavioral toxicity. The most hematological change was extreme microcytic hypochromic anemia. Leucocyte count increased in experimented fish. Moderate neutrophilia, monocytosis and lymphocytosis were observed. Serum total protein, albumin, and globulin concentrations were significantly diminished. Overall, increments over control were recognized in serum urea, creatinine and acid phosphatase. However, serum glucose, total lipid, cholesterol, serum ALT and AST activity showed a significant decrease in fish exposed to both concentrations of PRO. Serum IgM concentrations insignificantly changed in treated fish except for on the 21st day of exposure to 3.6 µg/ L of PRO, while serum lysozyme significantly decreased. Furthermore, total protein, lipid and glycogen concentrations in muscles and the liver exhibited a decreasing trend at all concentrations. Moreover, histopathological alterations in the liver, kidney, and muscles occurred exclusively after treatment. From the obtained results, it is assumed that profenofos induced general toxic impacts under field conditions and might disturb ecologically relevant processes.

Immune-antioxidant trait, growth, splenic cytokines expression, apoptosis, and histopathological alterations of Oreochromis niloticus exposed to sub-lethal copper toxicity and fed thyme and/or basil essential oils enriched diets

Two experiments were conducted in this study, using 250 Oreochromis niloticus (O. niloticus) (average weight 30.28 ± 0.27 g). The first experiment was conducted to investigate the 96-h lethal concentration 50 (LC₅₀) of copper chloride (CuCl₂) using the probit analysis, seventy fish was divided into seven different concentration of CuCl₂ (0, 22, 23, 24, 25, 26, and 27 mg/L), the accurate Cu concentrations were (1.23, 5.36, 6.02, 6.98, 7.05, 7.93, 8.12 mg/L Cu). The second experiment was conducted for investigating the effect of dietary supplementation with thyme (Thymus vulgaris, T. vulgaris) and sweet basil (Ocimum basilicum, O. basilicum) essential oils (TEO and BEO respectively) against sub-lethal Cu exposure (1/10 96-h LC₅₀ of CuCl₂). About 180 fish was divided into six groups in triplicate (10 fish/replicate, 30 fish/group). Group 1 (C) was kept as a control group with no Cu exposure and was fed the control basal diet. Group 2 (C-Cu) was fed the control basal diet and simultaneously exposed to 1/10 of the 96 h LC₅₀ of CuCl₂ (2.574 mg/L) as a sub-lethal concentration of Cu, where the realistic Cu concentration was 3.976 mg/L. Group 3 (TEO) and group 4 (BEO) were fed the diets fortified with 1%TEO and BEO, respectively without exposure to Cu. Group 5 (TEO-Cu) and group 6 (BEO-Cu) were fed the diets fortified with 1%TEO and 1%BEO, respectively, and simultaneously exposed to 1/10 of the 96 h LC₅₀ of CuCl₂ (2.574 mg/L). The growth and behavioral performance, immunological response and its related gene expression, antioxidant status, stress biomarker indicators, apoptosis biomarkers, and histopathological alteration were investigated. The results of the first experiment showed that the 96-h LC₅₀ of CuCl₂ in O. niloticus was 25.740 mg/L with lower and upper confidence limits of 25.152 and 26.356 mg/L, respectively. The results of the second experiment showed that sub-lethal Cu exposure induced growth retardation (lowered final body weight, total weight gain, and specific growth rate %), behavioral abnormalities (slower swimming activity and feeding performance), immunosuppression (lowered nitric oxide, complement-3, lysozyme, total proteins, albumin, and globulin), and lowering the hepatic antioxidant functions (higher MDA, and lower SOD, CAT, and GPx) in the exposed fish. Furthermore, alteration in the immune-related genes expression (down-regulation of IL-10 and TGF-β and up-regulation of IL-1β, IL-6, IL-8, and TRL-4), hepato-renal dysfunction (elevated ALT, AST, urea, and creatinine), and high levels of serum stress indicators (cortisol and glucose) were markedly evident. sub-lethal Cu toxicity induced significant up-regulation of apoptosis biomarkers involving, nuclear factor-κβ (NF-κβ), Bcl-2 Associated X-protein (BAX), meanwhile, the expression of B-cell lymphoma 2 (BCL2) and Proliferating cell nuclear antigen (PCNA) was remarkably down-regulated. In addition, apoptosis was also evident by histopathological investigation of branchial, hepatic, and renal sections. TEO and/or BEO dietary supplementation mitigate the destructive impacts of sub-lethal Cu exposure in O. niloticus, depending on the results of our study, it could be concluded that TEO and BEO with a 1% dietary level could be a promising antioxidant, immunostimulant, anti-stress factors, and anti-apoptosis mediators against heavy metal contaminants (Cu) in O. niloticus, providing a solution to the problem of aquatic bodies pollution, consequently aiding in the development of aquaculture industry.

The Role of Zinc Microelement in Aquaculture: a Review

Trace elements are required in optimum regimes for improving the productivity and wellbeing of aquatic animals. Zinc is one of the main microelements involved in several functions in the animal's body. Zinc potentiates the metabolism function, synthesis of essential enzymes, and the formation of hormones associated with growth, reproduction, immunity, and antioxidative roles in aquatic animals. Several sources of zinc are regularly applied in aquaculture, including inorganic, organic, and nanoparticles. Many studies examined the effects of zinc supplementation in the diets of aquatic animals. The results indicated that zinc could be included in aquafeed in a dose-dependent manner. The effects of zinc depend on the dose, source, duration of feeding, animals' sizes, and experimental conditions. This article comprehensively discusses the results of relevant studies that investigated the effects of zinc on the performances of aquatic animals. The review also intended to update the academia with the previous and current status of using zinc in aquafeed. Furthermore, the article includes up-to-date outputs of relevant studies of using different zinc sources in aquafeed.

Dietary Parsley Seed Mitigates Methomyl-Induced Impaired Growth Performance, Hemato-Immune Suppression, Oxidative Stress, Hepato-Renal Damage, and Pseudomonas aeruginosa Susceptibility in Oreochromis niloticus

The present experiment investigated the potential protective role of parsley (Petroselinum crispum) seed meal (PSM) in alleviating methomyl (MET)-adverse impacts on growth, whole-body composition, hematological indicators, hepatorenal function, immune response, oxidative status, and disease resistance to Pseudomonas aeruginosa. For this purpose, 225 healthy Nile tilapia (Oreochromis niloticus) were allotted into five groups (45 fish/group in triplicate). One group was reared in clean water and fed a non-supplemented basal diet, while the other groups were exposed to 20.39 μg L^-1 MET and fed a non-fortified basal diet or basal diets supplemented with 0.5, 1.0, or 2.0% of PSM for 60 days. The obtained data revealed significantly lower weight gain, feed intake, and specific growth rate, but higher feed conversion ratio and decreases in crude protein, lipid, and ash contents in the MET-exposed fish. Anemia, leukopenia, lymphocytopenia, and esonipenia were also obvious. Furthermore, MET-exposed fish had significantly higher serum levels of hepatic enzymes and renal damage products. Nevertheless, there was a significant depletion of enzymatic and non-enzymatic antioxidants and increased malondialdehyde, myeloperoxidase, and tumor necrosis factor-α levels in MET-exposed fish. The MET exposure significantly depressed lysozyme activity, nitric oxide, complement3, acetylcholinesterase activity, total proteins, globulin, and albumin levels in O. niloticus serum. Furthermore, pathological alterations in the liver and kidney were noted. The relative percentage of survival rate in MET-exposed fish was dramatically reduced on day 14 post-challenge with P. aeruginosa. The inclusion of PSM, on the other hand, greatly alleviated most of the MET-related negative effects. Taken together, the dietary intervention with PSM has a promising role in alleviating MET-deleterious impacts, rendering parsley seeds a viable aqua feed additive for O. niloticus.

The effect of nonylphenol exposure on the stimulation of melanomacrophage centers, estrogen and testosterone level, and ERα gene expression in goldfish

The present study tried to measure the formation of melanomacrophage centers (MMCs) in various organs of male and female goldfish exposed to nonylphenol (NP) and aimed to assess its relationship with the main sexual hormones, estrogen receptor expression, and the pigment content of the MMCs. Immature goldfish were exposed to 10^-6 and 10^-7 M NP for 25 days. After obtaining blood for measuring testosterone and estrogen (E2) levels, tissue samples were collected from various organs for histological studies, quantifying pigments using ImageJ software and chemical analysis, and measuring ERα gene expression. Results showed that the order of forming MMCs in various organs exposed to NP was liver > spleen > kidney, and the order of ERα gene expression was liver > testes > spleen > kidney in the male, and liver > spleen > kidney > ovaries in the female. Among the three pigments present in MMCs after exposure to the two doses of NP, melanin was more obvious (especially in the liver) and increased mostly in a dose-dependent manner in both sexes (especially in the male). Chemical analyses confirmed these results. Measurement of testosterone and E2 level in male and female goldfish showed that NP had more effect on the concentration of these hormones in male fish, indicating more endocrine-disrupting potential of NP against the male fish. Generally, the increase of melanin content of melanomacrophage centers coincided with the increase of ERα gene expression and decrease of testosterone level in goldfish after exposure to NP.

Assessment of reproductive toxicity of carbofuran and copper sulfate in male Nile tilapia (Oreochromis niloticus)

This study's hypothesis is that carbofuran and copper sulfate have a synergistic harmful impact on the fertility of male Nile tilapia. Hence, this study was designed to assess the toxic reproductive outcome of carbofuran, copper sulfate, and their mixture in male Nile tilapia. Sixty male Nile tilapia fishes were separated into four groups (15 fish/group). The control group; carbofuran group, was given dechlorinated tap water containing 0.02 mg/L (1/10 dose of LC50) carbofuran; copper group was given dechlorinated tap water containing 4.0 mg/L (1/10 dose of LC50) copper sulfate; carbofuran + copper sulfate group received dechlorinated tap water containing 0.02 mg/L carbofuran plus 4.0 mg/L copper sulfate. After 6 weeks, results revealed a significant rise in testicular malondialdehyde levels and a significant decrease in testicular reduced glutathione contents among all experimental groups compared to the control group. Testicular testosterone levels were significantly declined in copper and combined groups compared to the control. The seminal evaluation using computer-assisted sperm analysis showed a significant decline in the progressive motility percentage, motile ratio percentage, sperm concentration, curvilinear velocity, straight-line velocity, average path velocity, and wobble in all intoxicated groups, particularly, the combined group. The histopathology of testes in all intoxicated groups revealed a detachment of the basal membrane of some seminiferous tubules, and others were free from spermatogonia and spermatozoa with interstitial eosinophilic granular cell infiltration. Testicular lesions were more severe in the combined group. Finally, it was concluded that carbofuran and copper sulfate exerted a negative effect on the reproductive function of male Nile tilapia, and they have a synergistic harmful impact on the fertility of male Nile tilapia.

Chronic exposure to nonylphenol induces oxidative stress and liver damage in male zebrafish (Danio rerio): Mechanistic insight into cellular energy sensors, lipid accumulation and immune modulation

Nonylphenol (NP), an environmentally persistent and toxic endocrine-disrupting chemical with estrogenic properties, has severe implications on humans and wildlife. Accumulating evidence demonstrates the toxic response of NP on the developmental process, nervous system, and reproductive parameters. Although NP exposure has been implicated in chronic liver injury, the underlying events associated with hepatic pathophysiology remain less investigated. Using male zebrafish (Danio rerio) as the model, the present study investigates the impact of environmentally relevant concentrations of NP (50 and 100 μg/L, 21 days) on hepatic redox homeostasis vis-à-vis cellular energy sensors, inflammatory response, and cell death involving a mechanistic insight into estrogen receptor (ER) modulation. Our results demonstrate that congruent with significant alteration in transcript abundance of antioxidant enzymes (SOD1, SOD2, Catalase, GPx1a, GSTα1), chronic exposure to NP promotes ROS synthesis, more specifically superoxide anions and H₂O₂ levels, and lipid peroxidation potentially through elevated NOX4 expression. Importantly, NP perturbation of markers associated with fatty acid biosynthesis (srebf1/fasn) and cellular energy-sensing network (sirt1/ampkα/pgc1α) indicates dysregulated energy homeostasis, metabolic disruption, and macrovesicular steatosis, albeit with differential sensitivity at the dose level tested. Besides, elevated p38-MAPK phosphorylation (activation) together with loss of ER homeostasis at both mRNA (esr1, esr2a, esr2b) and protein (ERα, ERβ) levels suggest that NP modulation of ER abundance may have a significant influence on hepatic events. Elevated expression of inflammatory markers (TLR4, p-NF-κB, TNF-α, IL-6, IL-1β, and NOS2) and pro-apoptotic and necrotic regulators, e.g., Bax, caspase- 8, -9 and cleaved PARP1 (50 kDa), indicate chronic inflammation and hepatotoxicity in NP-exposed males. Collectively, elevated oxidative stress, metabolic dysregulation and immune modulation may lead to chronic liver injury in organisms exposed to metabolic disrupting chemicals.

Overfeeding-Induced Obesity Could Cause Potential Immuno-Physiological Disorders in Rainbow Trout (Oncorhynchus mykiss)

Although over-nutrition from overfeeding-induced obesity is known to be highly associated with metabolic and immunological disorders in humans, little is known about overfeeding-induced obesity in fish farming. The purpose of this study was to investigate changes in immuno-physiological parameters, to better understand the potential risk of overfeeding-induced obesity in fish. Commercial feed was provided to fish in the overfed group until they refuse to eat, but fish in the control group was fed with the feed at 1% bodyweight per day. The hemato-serological, histological, and immunological changes were observed at weeks 2 and 8. Rainbow trout leukocytes were co-incubated with oxidized low-density lipoprotein (OxLDL), and the phagocytes engulfing the OxLDL and the presence of apoptotic cells were evaluated. The body weight, body mass index (BMI), and hepatosomatic index (HSI) index were significantly higher in the overfed group, and high lipid accumulation and fatty changes were also observed in their livers, indicating that the feeding regime used in this study led to overfeeding-induced obesity. Likewise, much higher numbers of and larger vacuoles were observed in overfed fish macrophages, showing unclear boundaries between the cytoplasm and extracellular space. In the overfed group, the expression of IL-10, HSP70, TLR2, and CD36 was significantly higher, and lymphocyte apoptosis was more evident, indicating that overfeeding-induced obese fish might have immunologic disorders. This was the first study to demonstrate that overfeeding-induced obesity could cause an immune-physiological imbalance in rainbow trout, making them more vulnerable to infectious diseases and various stressful conditions. This study will contribute to improvements in fish nutrition, feeding practices, fish nutrition, and disease prevention in the aquaculture industry.

Inorganic mercury and dietary safe feed additives enriched diet impacts on growth, immunity, tissue bioaccumulation, and disease resistance in Nile tilapia (Oreochromis niloticus)

Little is known about the impacts of dietary exposure to inorganic mercury (Hg) for a long duration on the health indicators, growth, and disease resistance in Oreochromis niloticus. Accordingly, the current study was designed to assess the effects of Hg contaminated diets on blood biochemistry, growth, chemical composition, Hg bioaccumulation in the tissues, histopathology of liver and head kidneys, and disease resistance to Aeromonas hydrophila of O. niloticus. Also, the efficiency of citronella oil, geranium oil (GO), curcumin (CUR), Bacillus toyonensis (BT), and Bacillus subtilis (BS) as dietary supplements on reversing the negative impacts of Hg were assessed. A total of 240 tilapia fingerlings were assigned to eight dietary treatments fed on the basal diet (G1), G1 diet contaminated with 50 ppm Hg (G2), whereas the other groups fed the G2 diet and enriched with 400 mg CO (G3), 400 mg GO (G4), 200 mg CUR (G5), 7 × 10⁷ cells BT (G6), 7 × 10⁷ cells BS (G7), and 7 × 10⁷ BT + BS/ kg diet (G8) for 16 weeks. The obtained results showed that fish fed on the G2 diet had significantly impaired growth performance indicators, blood parameters, and resistance to bacterial infection compared with fish in the control group. Additionally, distinct pathological perturbations in liver and head kidneys were observed. In contrast, fish groups G3 to G8 had a significant enhancement in the growth performance, Hg bioaccumulation in fish tissues, blood biochemistry, and resistance against A. hydrophila infection compared with fish in the G2 group. Maximum improvement was recorded in G5, G6, and G8. Conclusively, from both health and an economic point of view, these results suggested that several benefits might be gained by adding these additives, especially CUR, BT, and BT + BS, on growth enhancement and ameliorating Hg negative impacts in O. niloticus.

Disruptive effects of nonylphenol on reproductive hormones, antioxidant enzymes, and histology of liver, kidney and gonads in Caspian trout smolts

The endocrine-disrupting effect of pollutants such as alkylphenols has been considered a major concern during recent years. Although the effects of nonylphenol on the reproductive hormones of fish have been investigated in several studies, the effect of this endocrine disruptor on reproductive hormones of immature fish and salmonid smolts has been less addressed. The present work studied the effects of 1, 10 and 100 μg/l concentrations of nonylphenol on the levels of plasma reproductive hormones and liver antioxidant enzymes as well as on histopathology of reproductive and non-reproductive organs of male and female Caspian brown trout (Salmo trutta caspius) smolts after 21 days of exposure. The results of the present study showed that environmentally relevant concentrations of nonylphenol affected plasma levels of sex steroids; gonadotropins, phosphorus, estradiol to testosterone ratio, and also caused histopathological lesions in liver, kidney and testis tissues of immature Caspian brown trout during smolting. Nonylphenol significantly increased the levels of estradiol in plasma of both male and female smolts exposed to nonylphenol compared with the control groups. Exposure to nonylphenol decreased testosterone and FSH levels in both genders. It has also increased plasma levels of LH in females but did not affect LH levels in male fish. Liver SOD and CAT content was decreased in nonylphenol-exposed smolts. Therefore, the release of this economically valuable and endangered species into the rivers contaminated with nonylphenol should be avoided as it can have significant effects on the development and reproductive function of smolts.

Melamine and curcumin enriched diets modulate the haemato-immune response, growth performance, oxidative stress, disease resistance, and cytokine production in oreochromis niloticus

Currently, feed adulteration and contamination with melamine (MEL) are considered one of the serious issues in the aquatic industry. With the limited studies of MEL exposure alone in fish, its adverse impacts on fish cannot be evaluated well. Accordingly, this study aimed to investigate the effects of MEL containing diets on the immune response, disease resistance to Aeromonas hydrophila, growth performance, chemical composition, immune-related genes expression, and histopathology of both spleen and head kidneys. Also, the efficacy of curcumin (CUR) dietary supplementation to alleviate MEL negative impacts were evaluated. A total of 180 apparently healthy Oreochromis niloticus (O. niloticus) were divided into four groups with three replicates fed the basal diet only, basal diet fortified with 200 mg/kg CUR, basal diet containing 1 % MEL, or a basal diet containing CUR + MEL. The results displayed that MEL significantly reduced growth performance indices and body crude lipid contents. Anemic, leukopenic, lymphocytopenic, heterocytopenic, esonipenic, hypoproteinemic and hypoalbuminic conditions were apparent. Moreover, depleted immune and antioxidant indicators including lysozyme activity, nitric oxide, immunoglobulin M, complement 3, glutathione peroxidase, and superoxide dismutase enzyme activity were recorded. Also, MEL reduced the disease resistance of O. niloticus to bacterial infection. Furthermore, MEL induced downregulation of mRNA levels of interleukin 1β and tumor necrosis factor α in the spleen together with obvious pathological perturbations in both spleen and head kidneys. The CUR addition resulted in a significant enhancement in most indices. These results may conclude that MEL could alter both innate and adaptive immune responses via the negative transcriptional effect on immune-related genes together with the oxidative damage of the immune organs. Furthermore, CUR dietary supplements could be advantageous for mitigating MEL negative impacts, thus offering a favorable aquafeed additive for O. niloticus.

Assessment of hematological, hepato-renal, antioxidant, and hormonal responses of Clarias gariepinus exposed to sub-lethal concentrations of oxyfluorfen

Little is known about the effects of oxyfluorfen, a diphenyl ether herbicide, exposure on the African catfish (Clarias gariepinus) health. Consequently, the existing investigation was designed to highlight the impacts of oxyfluorfen exposure on C. gariepinus hematological indices, liver and kidney functions, reproductive hormones, and oxidative status. Furthermore, a consequent 10-day depuration period was adopted to evaluate the recovery of the disturbed indicators to normal values. In the first experiment, the 96-h lethal concentration 50 (LC₅₀) of oxyfluorfen for C. gariepinus was determined using probit analysis. Next, in a second experiment, 180 healthy fish (average initial body weight: 164.23 ± 0.24) were randomly assigned to 4 experimental groups exposed to 0, 1/10, 1/8, or 1/5 96-h LC₅₀ of oxyfluorfen. The hematological profile, hepatic enzymes, kidney damage byproducts, reproductive hormones, oxidative stress, and lipid peroxidation indicators together with acetylcholinesterase (AChE) content were assessed. A histopathological examination of the hepatic, renal, brain, and testicular tissues was accomplished. Moreover, the expression of the oxidative stress-related gene was carried out. The results showed that 96-h LC₅₀ of oxyfluorfen for C. gariepinus was 11.698 mg/L. Exposure to sublethal levels of oxyfluorfen induced macrocytic hypochromic anemia, leukopenia, lymphopenia, monocytopenia, and eosinopenia. Also, a concentration-dependent increase in alanine transaminase, alkaline phosphatase, aspartate transaminase, urea, creatinine, catalase, and malondialdehyde was detected following oxyfluorfen exposure together with upregulation of catalase gene. But, significant concentration-dependent reductions in AChE, glutathione transferase, reduced to oxidized glutathione ratio, estradiol, and testosterone activities were recorded. These biochemical alterations were accompanied by pathological perturbations in hepatic, renal, brain, and testicular tissues. Following 10 days of recovery, only the hematological impairments were abolished. Conclusively, the herbicides oxyfluorfen could induce multiple negative impacts on C. gariepinus with oxidative stress as a probable underlying mechanism. Additionally, a recovery period of 10 days was not enough to restore these impairments.