Chemically and Green Synthesized ZnO Nanoparticles Alter Key Immunological Molecules in Common Carp (Cyprinus carpio) Skin Mucus

Temporal and Dosage Impact of Magnesium Oxide Nanoparticles on Grass Carp: Unveiling Oxidative Stress, DNA Damage and Antioxidant Suppression

Magnesium oxide nanoparticles (MgO NPs) have gained significant importance in biomedicine and variety of nanotechnology-based materials used in the agriculture and biomedical industries. However, the release of different nanowastes in the water ecosystem becomes a serious concern. Therefore, this study was executed to evaluate the toxic impacts of MgO NPs on grass carp. A total of 60 grass carp were randomly divided in three groups (G0, G1, and G2). Fish reared in group G0 were kept as control while fish of groups G1 and G2 were exposed to 0.5mg/L and 0.7mg/L MgO NPs respectively, mixed in water for 21 days. The 96h median lethal concentration (LC50) of MgO NPs was found to be 4.5mg/L. Evaluation of oxidative stress biomarkers, antioxidant enzymes, DNA damage in different visceral organs and the presence of micronuclei in erythrocytes were determined on days-7, 14, and 21 of the trial. Results revealed a dose and time-dependent significantly increased values of reactive oxygen species, lipid peroxidation product, DNA damage in multiple visceral organs and formation of micronuclei in the erythrocytes of treated fish (0.7mg/L). The results on antioxidant profile exhibited significantly lower amounts of total proteins, catalase, superoxide dismutase and peroxidase in visceral organs of the fish exposed to MgO NPs (0.5 and 0.7mg/L) at day 21 of trial compared to control group. In conclusion, it has been recorded that MgO NPs severely influence the normal physiological functions of the grass carp even at low doses.

Aquatic assessment of the chelating ability of Silica-stabilized magnetite nanocomposite to lead nitrate toxicity with emphasis to their impact on hepatorenal, oxidative stress, genotoxicity, histopathological, and bioaccumulation parameters in Oreochromis niloticus and Clarias gariepinus

BACKGROUND

In recent years, anthropogenic activities have released heavy metals and polluted the aquatic environment. This study investigated the ability of the silica-stabilized magnetite (Si-M) nanocomposite materials to dispose of lead nitrate (Pb(NO3)2) toxicity in Nile tilapia and African catfish.

RESULTS

Preliminary toxicity tests were conducted and determined the median lethal concentration (LC50) of lead nitrate (Pb(NO3)2) to Nile tilapia and African catfish to be 5 mg/l. The sublethal concentration, equivalent to 1/20 of the 96-hour LC50 Pb(NO3)2, was selected for our experiment. Fish of each species were divided into four duplicated groups. The first group served as the control negative group, while the second group (Pb group) was exposed to 0.25 mg/l Pb(NO3)2 (1/20 of the 96-hour LC50). The third group (Si-MNPs) was exposed to silica-stabilized magnetite nanoparticles at a concentration of 1 mg/l, and the fourth group (Pb + Si-MNPs) was exposed simultaneously to Pb(NO3)2 and Si-MNPs at the same concentrations as the second and third groups. Throughout the experimental period, no mortalities or abnormal clinical observations were recorded in any of the treated groups, except for melanosis and abnormal nervous behavior observed in some fish in the Pb group. After three weeks of sublethal exposure, we analyzed hepatorenal indices, oxidative stress parameters, and genotoxicity. Values of alkaline phosphatase (ALP), gamma-glutamyl transferase (GGT), urea, and creatinine were significantly higher in the Pb-intoxicated groups compared to the control and Pb + Si-MNPs groups in both fish species. Oxidative stress parameters showed a significant decrease in reduced glutathione (GSH) concentration, along with a significant increase in malondialdehyde (MDA) and protein carbonyl content (PCC) concentrations, as well as DNA fragmentation percentage in the Pb group. However, these values were nearly restored to control levels in the Pb + Si-MNPs groups. High lead accumulation was observed in the liver and gills of the Pb group, with the least accumulation in the muscles of tilapia and catfish in the Pb + Si-MNPs group. Histopathological analysis of tissue samples from Pb-exposed groups of tilapia and catfish revealed brain vacuolation, gill fusion, hyperplasia, and marked hepatocellular and renal necrosis, contrasting with Pb + Si-MNP group, which appeared to have an apparently normal tissue structure.

CONCLUSIONS

Our results demonstrate that Si-MNPs are safe and effective aqueous additives in reducing the toxic effects of Pb (NO3)2 on fish tissue through the lead-chelating ability of Si-MNPs in water before being absorbed by fish.

Copper-oxide nanoparticles effects on goldfish (Carassius auratus): Lethal toxicity, haematological, and biochemical effects

The advancement of nanotechnology and the widespread use of nanoparticles (NPs) in various industries have highlighted the importance of studying the potential harmful effects of nanomaterials on organisms. This study aimed to evaluate the lethal toxicity thresholds of Copper Oxide Nanoparticles (CuO-NPs). The investigation focused on examining the sub-lethal toxicity effects of CuO-NPs on blood parameters, as well as their influence on the gill tissue and liver of goldfish (Carassius auratus). Goldfish were exposed to varying concentrations of CuO-NPs (10, 20, 30, 40, 60, 80, and 100 mg/L) for 96 h. The Probit software was employed to determine the LC50 (lethal concentration causing 50% fish mortality) by monitoring and documenting fish deaths at 24, 48, 72, and 96-hour intervals. Subsequently, sub-lethal concentrations of 5% LC50 (T1), 10% LC50 (T2), and 15% LC50 (T3) of CuO-NPs were administered based on the LC50 level to investigate their effects on haematological parameters, encompassing the number of red blood cells and white blood cells, hematocrit and haemoglobin levels, mean corpuscular volume, mean corpuscular haemoglobin and mean corpuscular haemoglobin concentration. Additionally, histopathological examinations were conducted on the gill and liver tissues of the studied fish. Results indicated concentration-response of fish mortalities. In general, changes in the blood biochemical parameters of fish exposed to sub-lethal concentrations of CuO-NPs included a significant decrease in leukocyte count and glucose level and an increase in protein and triglyceride levels. Furthermore, an escalation in tissue damage such as gill apical and basal hyperplasia, lamellae attachment, squamous cell swelling, blood cell infiltration, and cellular oedema in gills tissue. and bleeding, increased sinusoidal space, necrosis, lateralization of the nucleus, cell swelling, and water retention in the liver. The findings showed dose-dependent increasing toxicity in goldfish specimens exposed to CuO-NPs.

Synergistic interaction of nanoparticles and probiotic delivery: A review

Nanotechnology is an expanding and new technology that prompts production with nanoparticle-based (1-100 nm) organic and inorganic materials. Such a tool has an imperative function in different sectors like bioengineering, pharmaceuticals, electronics, energy, nuclear energy, and fuel, and its applications are helpful for human, animal, plant, and environmental health. In exacting, the nanoparticles are synthesized by top-down and bottom-up approaches through different techniques such as chemical, physical, and biological progress. The characterization is vital and the confirmation of nanoparticle traits is done by various instrumentation analyses like UV-Vis spectrophotometry (UV-Vis), Fourier transform infrared spectroscopy, scanning electron microscope, transmission electron microscopy, X-ray diffraction, atomic force microscopy, annular dark-field imaging, and intracranial pressure. In addition, probiotics are friendly microbes which while administered in sufficient quantity confer health advantages to the host. Characterization investigation is much more significant to the identification of good probiotics. Similarly, haemolytic activity, acid and bile salt tolerance, autoaggregation, antimicrobial compound production, inhibition of pathogens, enhance the immune system, and more health-beneficial effects on the host. The synergistic effects of nanoparticles and probiotics combined delivery applications are still limited to food, feed, and biomedical applications. However, the mechanisms by which they interact with the immune system and gut microbiota in humans and animals are largely unclear. This review discusses current research advancements to fulfil research gaps and promote the successful improvement of human and animal health.

The cerium oxide nanoparticles toxicity induced physiological, histological and biochemical alterations in freshwater mussels, Unio crassus

INTRODUCTION

Releasing of cerium oxide nanoparticles (nano-CeO2) to the nature has increased due to the widespread use in many fields ranging from cosmetics to the food industry. Therefore, nano-CeO2 has been included in the Organization for Economic Co-operation and Development's (OECD) priority list for engineering nanomaterials. In this study, the effects of nano-CeO2 on the freshwater mussels were investigated to reveal the impact on the freshwater systems on model organism.

METHODS

First, the chemical and structural properties of nano-CeO2 were characterized in details. Second, the freshwater mussels were exposed to environmentally relevant concentrations of nano-CeO2 as 10 mg, 25 mg and 50 mg/L during 48-h and 7-d. Third, after the exposure periods, hemolymph and tissue samples were taken to analyse the Total Hemocyte Counts (THCs) histology and oxidative stress parameters (total antioxidant status, glutathione, glutathione-S-transferase, and advanced oxidative protein products).

RESULTS

Significant decrease of the THCs was observed in the nano-CeO2 exposed mussels compared to the control group (P < 0.05). The histological results showed a positive association between nano-CeO2 exposure concentration in the water and level of tissue damage and histopathological alterations were detected in the gill and the digestive gland tissues. Oxidative stress parameters were slightly affected after exposure to nano-CeO2 (P > 0.05). In conclusion, this study showed that acute exposure of freshwater mussels to nano-CeO2 did not pose significant biological risk. However, it has been proven that mussels are able to accumulate nano-CeO2 significantly in their bodies.

CONCLUSION

This suggests that nano-CeO2 may be a potential risk to other organisms in the ecosystem through trophic transfer in the food-web based on their habitat and niche in the ecosystem.

Antifungal Properties of Bio-AgNPs against D. pinodes and F. avenaceum Infection of Pea (Pisum sativum L.) Seedlings

Ascochyta blight and Fusarium root rot are the most serious fungal diseases of pea, caused by D. pinodes and F. avenaceum, respectively. Due to the lack of fully resistant cultivars, we proposed the use of biologically synthesized silver nanoparticles (bio-AgNPs) as a novel protecting agent. In this study, we evaluated the antifungal properties and effectiveness of bio-AgNPs, in in vitro (poisoned food technique; resazurin assay) and in vivo (seedlings infection) experiments, against D. pinodes and F. avenaceum. Moreover, the effects of diseases on changes in the seedlings' metabolic profiles were analyzed. The MIC for spores of both fungi was 125 mg/L, and bio-AgNPs at 200 mg/L most effectively inhibited the mycelium growth of D. pinodes and F. avenaceum (by 45 and 26%, respectively, measured on the 14th day of incubation). The treatment of seedlings with bio-AgNPs or fungicides before inoculation prevented the development of infection. Bio-AgNPs at concentrations of 200 mg/L for D. pinodes and 100 mg/L for F. avenaceum effectively inhibited infections' spread. The comparison of changes in polar metabolites' profiles revealed disturbances in carbon and nitrogen metabolism in pea seedlings by both pathogenic fungi. The involvement of bio-AgNPs in the mobilization of plant metabolism in response to fungal infection is also discussed.

Mitigation of haemato-genotoxic and stress response effects in Cyprinus carpio via silymarin dietary supplementation following deltamethrin exposure

The study examined the potential of Silymarin, a blend of bioactive flavonolignans extracted from the milk thistle Silybum marianum, to mitigate Deltamethrin-induced toxicity in the blood of Cyprinus carpio. Fish were exposed to Deltamethrin (0.66 μg/L), the plant extract, or a combination of both for a duration of thirty days. Various parameters, including serum biochemical markers, erythrocytic abnormalities, and genotoxicity endpoints, were assessed. Results indicated a significant (p < 0.05) increase in the levels of AST, ALT, ALP, blood urea nitrogen, creatinine, glucose, cholesterol, and TLC in the fish exposed to the pesticide. Conversely, total protein, TEC, and Hb showed a notable decrease. There was also a notable rise in micronuclei and erythrocytic abnormalities such as acanthocytes, microcytes, and notched cells. Under ultrastructural examination, phenotypic deformities like spherocytosis, discocytes, and clumped erythrocytes were observed. However, dietary supplementation of silymarin (1 g/kg) significantly restored the biochemical, genetic, and cellular parameters, resembling those of the control group. This suggests the potential of this plant extract in protecting the common carp, Cyprinus carpio, from Deltamethrin-induced damage by scavenging free radicals and reducing DNA oxidative stress.

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.

Comparative Effect of Chemical and Green Zinc Nanoparticles on the Growth, Hematology, Serum Biochemical, Antioxidant Parameters, and Immunity in Serum and Mucus of Goldfish, Carassius auratus (Linnaeus, 1758)

Recently, nano feed supplement research has great attention to improving healthy aquatic production and improving the aquatic environment. With the aims of the present study, chemical and green synthesized nanoparticles are characterized by various instrumentation analyses, namely UV-Vis spectrophotometry (UV-Vis), X-ray diffraction (XRD), Fourier transform infra-red (FTIR) spectroscopy, and scanning electron microscope (SEM). After characterization analysis of these nanoparticles utilized in aquatic animals, the composition ratio is as follows: controls (without ZnO-NPs (0 mg/L)), T1 (0.9 mg/L ZnO-NPs), T2 (1.9 mg/L ZnO-NPs), T3 (0.9 mg/L GZnO-NPs), T4 (1.9 mg/L GZnO-NPs). SEM investigation report demonstrates that the structure of the surface of green synthesized zinc oxide nanoparticles (GZnO-NPs) was conical shape and the size ranging was from 60 to 70 nm. Concerning hematological parameters, the quantity of hemoglobin increased in different doses of green zinc nanoparticles, but the values of MCV and MCH decreased somewhat. However, this decrease was the highest in the T2 group. Total protein and albumin decreased in T2 and triglyceride, cholesterol, glucose, cortisol, creatinine, and urea increased, while in T3 and T4 groups, changes in biochemical parameters were evaluated as positive. Mucosal and serum immunological parameters in the T2 group showed a significant decrease compared to other groups. In zinc nanoparticles, with increasing dose, oxidative damage is aggravated, so in the T2 group, a decrease in antioxidant enzymes and an increase in MDA were seen compared to other groups. In this regard, the concentration of liver enzymes AST and ALT increased in the T2 group compared with control and other groups. This can confirm liver damage in this dose compared with control and other groups. This research work suggests that green synthesized form of zinc nanoparticles in higher doses have less toxic effects in comparison to the chemical form of zinc nanoparticles and can act as suitable nutrient supplements in aquatic animals.

Is the trend toward a sustainable green synthesis of copper oxide nanoparticles completely safe for Oreochromis niloticus when compared to chemical ones?: using oxidative stress, bioaccumulation, and histological biomarkers

Scientists worldwide have noticed that cutting-edge technologies can be used to produce nanoparticles (NPs) in a sustainable and environmentally friendly way, instead of the old methods. However, the effectiveness of this approach for aquatic environments and species still needs to be determined. Therefore, this study aims to compare between the toxicity of green and chemically synthesized copper oxide nanoparticles (GS and CS) CuO NPs at two different concentrations on Nile tilapia (Oreochromis niloticus) using various biomarkers. CuO NPs' formation was proved, and their different characterizations were recorded. Then, the fish samples were randomly allocated in glass aquaria into five groups: one acted as a control group, and the other groups were exposed to two concentrations (25 and 50 mg/L) of GS-CuO NPs and CS-CuO NPs, separately, for 4 days. After the experimental time, in all groups that were exposed to two concentrations of both synthesized CuO NPs, the results revealed that glutathione peroxidase (GPx), catalase (CAT), superoxide dismutase (SOD), and thiobarbituric acid reactive substances (TBARS) levels were elevated in the liver and gills compared to glutathione reduced (GSH) content, which showed a significant decline. Bioaccumulation of Cu was more prevalent in the liver than in the gills, and the highest bioaccumulation capacity was more evident in the groups exposed to CS-CuO NPs. Moreover, the bioaccumulation of Cu caused severe histological changes in the liver and gills. In conclusion, the results suggested that GS-CuO NPs revealed less toxicity than CS-CuO NPs to the examined fish. However, they are still toxic, and their toxic effect cannot be overlooked.

Bio-synthesized ZnO nanoparticles and sunlight-driven photocatalysis for environmentally-friendly and sustainable route of synthetic petroleum refinery wastewater treatment

The design of a green photocatalytic system that harnesses renewable and eco-friendly constituents holds the potential to offer valuable insights into alternative strategies for treating toxic multi-components in refinery water effluents. A significant challenge in implementing a practical and viable approach is the utilization of solar energy-an abundant, natural, and cost-effective resource-for photochemical processes within advanced oxidation processes. In this study, we explored the use of zinc oxide nanoparticles (ZnO NPs) as photocatalyst prepared via an environmentally friendly synthesis approach, resulting in the formation of crystalline wurtzite nanoparticles, with an average size of about 14 nm relatively spherical in shape. Notably, the extract derived from Moringa oleifera was employed in this investigation. These nanoparticles were characterized and validated using various characterization techniques, including X-ray diffraction, transmission electron microscopy, field emission scanning electron microscopy, and energy dispersive X-ray spectroscopy. For comparison, conventionally synthesized ZnO NPs were also included in the evaluations. The findings reveal that, under illumination, biosynthesized ZnO nanoparticles (NPs) exhibit photocatalytic performance in effectively breaking down the organic compounds present in synthetic petroleum wastewater. Photochemical analysis further illustrates the degradation efficiency of Green-ZnO, which, within 180 min of irradiation resulted in 51%, 52%, 88%, and 93% of removal for Phenol, O-Cresol. Under optimal loading conditions, NPs produced via the green synthesis approach perform better when compared to chemically synthesized ZnO. This significant improvement in photocatalytic activity underscores the potential of eco-friendly synthesis methods in achieving enhanced water treatment efficiency.

Oxidative stress, genotoxic effects, and other damages caused by chronic exposure to silver nanoparticles (Ag NPs) and zinc oxide nanoparticles (ZnO NPs), and their mixtures in zebrafish (Danio rerio)

This study assessed the oxidative stress impacts of Ag NPs and ZnO NPs and their mixtures in zebrafish (Danio rerio). Zebrafish were exposed to sublethal concentrations of each NP and a mixture for 28 days followed by a 28-day recovery period (without NP exposure) and measurements made on hepatic levels of antioxidant enzymes (CAT, SOD, and GPx), MDA levels, expression of the genes for the Hsp70 and Hsp90, and MT, blood biochemical parameters (total protein, globulin, albumin, AST, ALT, ALP, and LDH), and genotoxicity in erythrocytes (via measurement of micronuclei (MN) and nuclear (NA) abnormalities). There was a tendency for an increase in the variation in the responses of antioxidant defense systems and there were higher MDA levels with increasing exposure concentration of Ag NPs and with increasing exposure time. Total protein, globulin, and albumin decreased during the exposure period, especially on the days of 28. Moreover, levels of AST and LDH increased significantly in the NPs co-exposure treatments, while levels of ALT and ALP significantly decreased. The highest expression levels for these genes occurred on day 14 and in the NPs co-exposure treatments. For exposure to both NPs individually and as a mixture, the frequency of MN and other NA were significantly increased (p < 0.05). During the recovery periods, most of the effects seen were reduced, most notably in the individual NPs treatments. The overall results suggest that the toxic effects of Ag NPs and ZnO NPs in combination significantly increase their toxicity in zebrafish.

Impacts of dietary zinc oxide nanoparticles on the growth and immunity of Nile tilapia could be ameliorated using Nigella sativa oil

BACKGROUND

Zinc nanoparticles are documented to be harmful to fish because their accumulation in fish bring about many irreversible changes in their health. Nigella sativa and its oil have been endorsed in aquaculture to improve fish health.

METHODS

Two hundred seventy experimental fish (113 ± 5 g body weight) were divided into 6 groups G1-6; control fish fed a diet without any treatment (G1), 0.3% of NSO (G2), 0.5% of NSO (G3), ZnO NPs (40 mg/kg diet) (G4), 0.3% of NSO and ZnO NPs (40 mg/kg diet) (G5), 0.5% of NSO and ZnO NPs (40 mg/kg diet) (G6), the trial lasted for six weeks.

RESULTS

Growth performance was enhanced in fish received diets containing NSO, final weight (FW), weight gain (WG), daily weight gain (DWG), and relative growth rate (RGR) were significantly increased with lower food conversion ratios (FCR) compared to the control. The hepatic glutathione peroxidase (GPx), catalase (CAT), and metallothionein (MT) were increased in response to ZnO NPs stress and only 0.5% NSO supplementation could ameliorate such increment. The immune-related genes [interleukin1-beta (IL-1β), tumor necrosis factor-beta (TNF-β), transforming growth factor-beta 2 (TGF-β2) and C-type lysozyme] as well as growth-related gene [insulin-like growth factor 1 (IGF1)] in liver showed an upregulation in fish fed with NSO diets. Administration of ZnO NPs lowered the resistance of Oreochromis niloticus against bacterial infection with Aeromonas hydrophila and NSO could enhance the immunity in the highest tested concentration (0.5%) (G₆).

CONCLUSIONS

The obtained results implied that NSO could enhance the oxidative and immune status of O. niloticus which could compensate ZnO NPs stress as well as experimental infection of a virulent strain of A. hydrophila. Our results revealed that NSO might increase fish growth and immunity only at a high dose (0.5%).

Impact of acute and sub-acute exposure of magnesium oxide nanoparticles on mrigal Cirrhinus mrigala

This experiment was conducted to investigate the impact of acute and sub-acute exposure of magnesium oxide nanoparticles on Mrigal Cirrhinus mrigala. For sub-acute tests 1/100,1/50,1/10 were selected based on the LC₅₀ at 96 h s. Protein, carbohydrate, and lipid, Aspartate aminotransferase, alanine transaminase, lactate dehydrogenase and DPPH, HRSA assays were analyzed in the gill, muscle, and liver of Mrigal. Protein and lipid levels increased on the 7th,14th day compared to control. Carbohydrate levels decreased on the 7th,14th day of exposure, and the enzymatical changes increased on the 7^th,14th day. Antioxidant levels highly increased in DPPH assay compared to the HRSA assay. This study provides the biochemical, antioxidant, and behavioral changes in relation to the exposure of MgO NPs.

A review on pathogenicity of Aeromonas hydrophila and their mitigation through medicinal herbs in aquaculture

Aeromonas hydrophila is a freshwater, facultatively anaerobic, chemo-organoheterotrophic bacterium that distressed fishes with gastroenteritis, septicemia and causes a disease known as Motile Aeromonas Septicemia (MAS), which affects the aquatic environment. Haemolysin, aerolysin, cytosine, gelatinase, enterotoxin and antimicrobial peptides have been identified as virulence factors in A. hydrophila. Medicinal herbs/plants and their uses are the instant, easily available, cost-effective, efficient and eco-friendly approach for socio-economic, sustainable development of modern aquaculture practice. Phytotherapy either through a dip or by incorporation into the diets is an alternative approach to synthetic pharmaceuticals to diminish the pathogenicity of aquatic environmental pathogens. Due to the presence of remarkable phytoconstituents like flavonoids, alkaloids, pigments, terpenoids, steroids and essential oils, the medicinal plant exhibits anti-microbial, appetite-stimulating, anti-stress, growth-promoting and immunostimulatory activities. Aqua-industry preferred phytotherapy-based techniques/compounds to develop resistance against a variety of aquatic pathogens in culturable fishes because they are inexpensive and environment-friendly. As a result, this review elaborates on the diverse applications of phytotherapy as a promising tool for disease management in aquaculture and a major step toward organic aquaculture.

Impact of Camellia sinensis Iron Oxide Nanoparticle on Growth, Hemato-biochemical and Antioxidant Capacity of Blue Gourami (Trichogaster trichopterus) Fingerlings

The effect of green tea (Camellia sinensis) iron oxide nanoparticles (nano-Fe) on the effectiveness, growth, antioxidant capacity, and immunological response of Trichogaster trichopterus (Blue gourami) fingerlings was investigated. UV-Visible, Fourier Transform Infrared, Scanning Electron Microscopy, Energy Dispersive X-ray, X-ray diffraction, Dynamic Light Scattering, and Zeta Potential spectroscopy were used to evaluate the biologically synthesized nano-Fe. Characterization revealed the hexagonal and spherical morphology with an average diameter of 114 nm. Six different experimental diets were supplied to the fish in duplicate for 60 days. The first diet served as a control (no nano-Fe supplementation), whereas the remaining five diets contained nano-Fe at concentrations of 10, 20, 30, 40, and 50 mg/kg (D1 to D5). The results indicated that fish fed a nano-Fe diet at a concentration of 40 mg/kg had improved growth performance, biochemical constituents, hematological parameters, and antioxidant activity in T. trichopterus, implying that it might be used as a vital feed supplement in ornamental fish culture.

Behavioral and physiological toxicity thresholds of a freshwater vertebrate (Heteropneustes fossilis) and invertebrate (Branchiura sowerbyi), exposed to zinc oxide nanoparticles (nZnO): A General Unified Threshold model of Survival (GUTS)

The toxic effects of Zinc oxide nanoparticles (nZnO) on Branchiura sowerbyi and Heteropneustes fossilis, was assessed in a 96-hour acute exposure regime using behavioral (including loss-of balance and clumping tendencies) and physiological (mucus secretion and oxygen consumption) endpoints. While the relationship between behavioral, physiological biomarkers, and exposure concentrations was assessed using correlation analysis, nZnO toxicity was further predicted using the General Unified Threshold model for Survival (GUTS). The time-dependent lethal limits for acute nZnO toxicity (LC₅₀) on B. sowerbyi were estimated to be 0.668, 0.588, 0.448, and 0.400 mg/l, respectively, at 24, 48, 72, and 96 h whereas for H. fossilis the LC50 values are 0.954, 0.905, 0.874 and 0.838 mg/l. Threshold effect values i.e., LOEC (Lowest Observed Effect Concentration), NOEC (No Observed Effect Concentration), and MATC (Maximum Acceptable Toxicant Concentration) threshold effect values at 96 h were higher for fish compared to the oligochaete. For B. sowerbyi, the GUTS-SD (stochastic death) model is a better predictor of nanoparticle exposure effects compared to the GUTS-IT (individual tolerance) model, however in the case of H. fossilis, the reverse pattern was observed. Oxygen consumption rate was negatively correlated to mortality under acute exposure duration. The strong negative correlation between mortality and oxygen consumption strongly suggests a metabolic-toxicity pathway for nZnO exposure effects. The higher toxicity threshold values i.e., LOEC, NOEC, and MATC for fish compared to the oligochaete invertebrate indicates greater risks for invertebrates compared to vertebrates, with resultant implications for local habitat trophic relationships.

Enhanced photodegradation of methylene blue from aqueous solution using Al-doped ZnS nanoparticles

The post-transition semiconducting material of pure zinc sulfide (ZnS) and various concentrations of aluminum (Al) (2.5 wt%, 5.0% wt, 7.5 wt%, and 10% calcined at 200 °C) doped ZnS nanoparticles (NPs) were synthesized by sol-gel procedure. The crystal-like nature and phase structure of the product were examined by powder XRD analysis. This analysis shows that the pure ZnS nanoparticle does not form any secondary phase. The functional group of synthesized materials was analyzed by FTIR examination. The energy gap of the materials is calculated using electro-optic analysis and the Kubelka-Munk equation varies from 3.04 nm to 3.63 nm. The photoluminescence studies show the wide emissions (blue to green) for pure ZnS and Al-doped ZnS nanomaterials. The SEM images show the spherical structure and the agglomerated nanostructures. The presence of Zn, S, and Al are confirmed by EDAX spectra. From HR-TEM studies, pure ZnS and Al-doped ZnS nanoparticles exhibit uniform particle sizes. The rate of degradation was observed using MB dye. MB dye has maximum wavelength (λ_max) of 664 nm. The dye degradation efficiency was improved as the dye ratio increased. Photocatalytic activities studies show the intensity of photocatalytic activities decreased for the maximum time interval. Doping of Al in ZnS boosts the photocatalytic activity. Hence, Al-doped ZnS appears to be better decomposing MB dye when exposed to visible light.

Comparative toxicity of silver nanoparticles and silver nitrate in freshwater fish Oreochromis mossambicus: A multi-biomarker approach

Silver nanoparticles (AgNPs) in the aquatic environment affect ecological repercussions and have fatal impacts on aquatic animals. The current study examined and correlated the toxicity of silver nitrate (AgNO₃) and silver nanoparticles (AgNPs) to the Mozambique tilapia, Oreochromis mossambicus. The comparative toxicity studies were done by exposing O. mossambicus to various doses of AgNO₃ and AgNPs (0, 25, 50, 75, and 100 μg/L) over a 7-day subacute exposure period. AAS analysis was used to detect Ag accumulation, while the histological examination established gill tissue damage. Oxidative stress affects lipid peroxidation (LPO) and protein carbonyl activity (PCA) in the gill tissue. Antioxidant parameters such as glutathione-S-transferase (GST), glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase activity (CAT), and non-enzymatic antioxidants such as metallothionein (MT) and reduced glutathione. The serum in the blood was used to determine non-specific immunological characteristics such as lysozyme (LYZ), myeloperoxidase (MPO), and respiratory burst activity (RBA). The neurotoxic impact of acetylcholine esterase activity (AChE) was investigated in brain tissues. The findings demonstrated that larger concentrations of AgNO₃ than AgNPs improved enzymatic antioxidant activities in the gill tissue. Histological examination of fish gills demonstrated that both AgNPs and AgNO₃ induced telangiectasia and epithelial cell hyperplasia. By increasing the concentration of AgNPs and AgNO₃, the present research demonstrated that silver accumulation leads to inefficient oxidative stress and altered enzymatic and non-enzymatic parameters, leading to cellular damage.

Growth, hemato-biochemical, immune-antioxidant response, and gene expression in Nile tilapia (Oreochromis niloticus) received nano iron oxide-incorporated diets

Nanotechnology has recently played a key role in tackling many aquacultures issues. Hence, the present study targets the evaluation of dietary inclusion of nano iron oxide (nFe₂O₃) on growth performance, hematology, immune-antioxidant responses, ionic regulation and expression of related genes in Nile tilapia (Oreochromis niloticus). Fish were fed supplementary nFe₂O₃ at rates of zero (control), 0.5, and 1 g/kg diet for 30 days. Obtained data demonstrated that nFe₂O₃ significantly (P < 0.05) augmented growth performance (final weight and length, body mass gain, specific growth rate, feed conversion ratio, and length gain rate). Hematological picture {RBCs, Hb, MCV, MCH and MCHC, and leukocytes interpretations (WBCs and monocytes)}; and biochemical indexes including (AST and ALT; total protein; and glucose, and cortisol) were significantly (P < 0.05) improved in nFe₂O₃ supplemented groups. Plasma ionic concentration was also altered with nFe₂O₃ supplementation, and 1g nFe₂O₃ revealed the most marked increase in plasma (Na⁺) potassium (K⁺) levels. Similarly, IgM, nitrous oxide (NO), and lysozyme activity, plus superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activities showed a remarkable improvement in 1g nFe₂O₃ group compared to the control. Expression of Insulin-Like Growth Factor-1 (IGF-1) and interleukin 1-β (IL-1β) genes were significantly up-regulated in nFe₂O₃ supplemented groups. Briefly, dietary nFe₂O₃ inclusion had enhanced properties on growth; hemato-biochemical; immune, antioxidative profiles; and related genes expression of O. niloticus, with a recommended concentration of 1g nFe₂O₃.

Protective effects of summer savory (Satureja hortensis) oil on growth, biochemical, and immune system performance of common carp exposed to pretilachlor herbicide

There are many reports on the deleterious effects of herbicides on aquatic organisms which lead to tremendous biological, environmental and economical damage. In this regard, in the present study, the protective effect of summer savory (Satureja hortensis) essential oil (SEO) against pretilachlor, one of the most used herbicides was investigated in common carp (Cyprinus carpio). The fish assigned to six treatment groups (T₁: control treatment; T₂: 25% LC₅₀ pretilachlor herbicide; T₃: 50% LC₅₀ pretilachlor herbicide; T₄: 1% SEO; T₅: 25% LC₅₀ pretilachlor herbicide + 1% SEO; and T₆: 25% LC₅₀ pretilachlor herbicide + 1% SEO) for 21 days. The results showed that the SEO-containing treatments significantly increased the survival rate (SR) (P < 0.05). The highest final weight (FW), specific growth rate (SGR), and feed conversion ratio (FCR) were observed in the T₄ treatment (P < 0.05). There was a significant increase in glucose (GLU) level in pretilachlor treatments and a significant decrease in SEO-containing treatments compared to the control (P < 0.05). The significantly highest total protein (TP) content was observed in T₄ treatment containing SEO. Cholesterol (CHOL) and triglyceride (TRIG) levels decreased in SEO-containing treatments with the lowest level in T₄ treatment (P < 0.05). Alternative complement pathway activity (ACH₅₀), activity levels of superoxide dismutase (SOD), and glutathione peroxidase (GP_X) showed an increasing trend in SEO-containing treatments with the highest level in T₄ treatment (P < 0.05). The activity of liver enzymes showed a significantly lowest level in T₄ treatment. To conclude, our findings revealed that the use of SEO in fish exposed to pretilachlor herbicide could improve growth, strengthen the immune system and exert a protective effect on common carp.

Biogenic Synthesis of ZnO Nanoparticles and Their Application as Bioactive Agents: A Critical Overview

Zinc oxide is a safe material for humans, with high biocompatibility and negligible cytotoxicity. Interestingly, it shows exceptional antimicrobial activity against bacteria, viruses, fungi, etc., especially when reduced to the nanometer size. As it is easily understandable, thanks to its properties, it is at the forefront of safe antimicrobials in this pandemic era. Besides, in the view of the 2022 European Green Deal announced by the European Commission, even science and nanotechnology are moving towards “greener” approaches to the synthesis of nanoparticles. Among them, biogenic ZnO nanoparticles have been extensively studied for their biological applications and environmental remediation. Plants, algae, fungi, yeast, etc., (which are composed of naturally occurring biomolecules) play, in biogenic processes, an active role in the formation of nanoparticles with distinct shapes and sizes. The present review targets the biogenic synthesis of ZnO nanoparticles, with a specific focus on their bioactive properties and antimicrobial application.

Mucuna pruriens seeds extract boosts growth, immunity, testicular histology, and expression of immune-related genes of mono-sex Nile tilapia (Oreochromisniloticus)

Nutraceuticals have received increased attention in sustainable aquaculture. Consequently, the present study aimed to evaluate the dietary effects of Mucuna pruriens (MP) seed extract on growth performance, immune status, hepatic function, biochemical profiles, gonadal histology, and expression of immune-related genes in mono-sex Nile tilapia (Oreochromis niloticus). Fish were allocated into four groups and received MP at rates of 0 (control), 2, 4, and 6 g/kg diet, respectively, for 90 days. The results revealed that MP significantly (P<0.05) modulated growth performance (specific growth rate, final length, and length gain rate, body mass gain, and feed conversion ratio), lysozyme activity, and liver enzymes (AST, ALT). However, a non-significant effect on nitric oxide (NO) or immunoglobulin M (IgM) levels was detected, whereas the dietary inclusion of MP had a hypoglycemic effect. In terms of plasma globulin, albumin, globulin/albumin ratio, and cortisol, the MP receiving groups showed insignificant difference (P<0.05) when compared to controls, except for the 2 g MP-supplemented group. The lower inclusion concentration of MP (2 g/kg diet) demonstrated the best result (P < 0.05) for gonadosomatic index (GSI) and plasma testosterone level that was consistent with the histological findings reflecting an improvement in the testicular development compared with the control group. Expressions of complement component (C5) and interleukin 1-β (IL-1β) genes were significantly up-regulated in MP receiving groups. In conclusion, M. pruriens can be used as a safe natural economic feed additive and a low inclusion level of 2 g/kg diet is recommended to improve growth, enhance immunity, maintain liver functioning, improve testicular development, and to modulate immune-related genes in the mono-sex O. niloticus.

Dietary Salvia officinalis leaves enhances antioxidant-immune-capacity, resistance to Aeromonas sobria challenge, and growth of Cyprinus carpio

The current perspective is a pioneer to assess the efficacy of Salvia officinalis leave powder (SOLP) on growth, intestinal enzymes, physiological and antioxidant status, immunological response, and gene expression of Common carp (Cyprinus carpio). We also looked into fish resistance after being challenged with Aeromonas sobria, a pathogenic zoonotic bacteria. Fish (N = 120) were fed four different experimental diets in triplicate for 8 weeks. The control diet (SOLP0 - without SOLP); meanwhile, the other three diets included SOLP of 2, 4, and 8 g kg^-1 concentrations (SOLP2, SOLP4, and SOLP8), respectively. Findings demonstrated that fish fed SOLP4 and SOLP8 diets had better growth performance and improved digestion by noticeable enhancing lipase and amylase enzymes activity than other groups. Additionally, the antioxidant (superoxide dismutase and glutathione peroxidase) and immune activities (immunoglobulin M, nitric oxide, and antiprotease) clarified a significant increase (p < 0.05) in SOLP4 and SOLP8 groups. Enriched diets with SOLP4 and SOLP8 exhibited better expression of splenic genes (IL-1β, IL-6, IL-10, TLR-2, and SOD), intestinal genes (Slc26a6) and (PepT1 or Slc15a1), and muscular genes (IGF-1 and SOD), while MSTN was down-regulated. After 8 weeks of the experimental trial, C. carpio challenged by A. sobria exhibited the highest cumulative mortality (66.67%), while SOLP8-dietary intervention showed the best results in enhancing the fish resistance against A. sobria by lessening mortalities to 13.33% followed by SOLP4 diet (20%). The outcomes indicate that the expression of splenic, muscular, and intestinal genes confirm the efficacy of SOLP on enhancing growth, digestion, and immune-antioxidant status, and recommend the potential use of SOLP especially at 4 g kg^-1 level as a valuable natural economic diet additive in C. carpio culture for sustaining aquaculture.

Silica nanoparticles are novel aqueous additive mitigating heavy metals toxicity and improving the health of African catfish, Clarias gariepinus

Silica nanoparticles (SiNPs) are among the non-toxic nanoparticles (NPs) that have magnetic capabilities. It is hypothesized that SiNPs may be able to reduce toxic effects exerted by a mixture of lead (Pb) and mercury (Hg) in African catfish Clarias gariepinus. The in vitro magnetic potential of SiNPs to absorb Pb and Hg was tested. Fish (N = 240) were divided into four groups in triplicates for 30 days. The first group served as control and the second group (SiNPs) was exposed to 1/10 of 96 h LC50 of SiNPs (14.45 mg/L). The third group (HMM) was exposed to 1/10 of 96-h LC50 of a mixture of mercury chloride (HgCl₂) and lead chloride (PbCl₂) equal to 0.04 mg/ L and 23.1 mg/L. The fourth group (SiNPs+ HMM) was exposed to a suspension composed of SiNPs, HgCl₂, and PbCl₂ at the same concentrations as the third group. Results showed that fish exposed to heavy metals revealed the following consequences; a significant decrease in hematological, immunological (complement-3 and nitric oxide), and antioxidants (total antioxidant capacity, glutathione peroxidase, superoxide dismutase, and catalase) indices, down-regulation of IL-1β, IL-8, TGF-β, NF-κβ, HSP70, and Hepcidin genes, the highest mortality rate (48.33%), higher values of alkaline phosphatase, alanine, and aspartate aminotransferases, urea, creatinine, and branchial malondialdehyde, marked up-regulation of CC chemokine and CXC chemokines, and high HMs residues levels in muscles. Extensive pathology showed degeneration with diffuse vacuolation of hepatopancreatic cells and hemorrhage in the HMM group. Interestingly, the exposed group to SiNPs and HMM demonstrated a decline of HMs concentration in fish muscles and modulated the abovementioned parameters with the regeneration of histological alterations of liver and gills. Based on the study outcomes, we highlight the importance and the safety of SiNPs as a novel aqueous additive to alleviate HMs toxicity and recommend using SiNPs for enhancing fish performance for sustaining aquaculture without adverting safety of human health by their little accumulation in muscular tissue.

Protective effects of Allium hirtifolium extract against foodborne toxicity of Zinc oxide nanoparticles in Common carp (Cyprinus carpio)

The use of nano-sized materials is increasingly growing, while consequent health and environmental risks are still disputed. On the other hand, plant extracts have been reported to improve fish general health status and enhance antioxidant capacity. Thus, the present study was aimed to assess potential effects of Allium hirtifolium extract (AHE) to fortify antioxidant responses of Common carp (Cyprinus carpio) exposed to foodborne Zinc oxide nanoparticles (ZnO-NPs). Five hundred and forty fish were randomly allocated into 18 tanks and received six diets including a basal diet (as control), basal diet incorporated with either 13 mg/kg (ZnO-25) or 26 mg/kg (ZnO-50) of ZnO-NPs, 1.5% AHE (AHE-1.5), and similar concentrations of ZnO-NPs plus AHE (ZnO-25-AHE) and (ZnO-50-AHE) for a period of 30 days. Results revealed that blood indices, stress biomarkers (glucose and cortisol), and antioxidant parameters and genes in AHE-1.5 group were significantly modulated and improved when compared to other groups (P < 0.05). In AHE-enriched groups, serum and liver tissue antioxidative parameters were enhanced as reflected in a noticeable decrease in malondialdehyde value and an increase in catalase, superoxide dismutase, glutathione peroxidase, and glutathione reductase. However, current results showed that diets incorporated with ZnO-NPs elevated the stress parameters besides a significant reduction for most measured biochemical parameters and AHE supplementation ameliorated these effects in terms of improving antioxidant parameters. In ZnO-25-AHE, and ZnO-50-AHE, the values for expression of GPx were found significantly (P < 0.05) different from that of ZnO-25 and ZnO-50. On the contrary, SOD showed a non-significant difference (P > 0.05) among control, ZnO-25, and ZnO-50-AHE, also in-between ZnO-25 and ZnO-25-AHE. The present results indicate that AHE supplementation could trigger antioxidant responses both at tissue and molecular levels suggesting its outstanding protective effects against foodborne toxicity of ZnO-NPs in Common carp.

Immune responses of Cyprinus carpio induced by protein extracts of Lernaea cyprinacea Linnaeus, 1758

Lernaea cyprinacea Linnaeus, 1758 is an ectoparasite showing widespread infections in tropical aquaculture, and the present study aimed to determine the specific immune responses against this parasite. For the experiment, whole parasite extracts were injected intraperitoneally into Cyprinus carpio Linnaeus, 1758, and samples of epidermal mucus and blood were drawn at 0, 1, 7 and 14-days post-injection (DPI). The results revealed high levels of protein, protease and lysozyme activities in the experimental fish which were injected with L. cyprinacea protein extract. In the epidermal mucus, the total protein concentration of the control fish was 460 μg/mL, and the level raised significantly to 800 μg/mL in the experimental fish. The lysozyme activity increased from 741.5 u/mL to a peak level of 1448.5 u/mL at 7DPI. The protease activity was also found elated gradually from 2.91 u/μL to 4.49 u/μL at 1 to 14 DPI. In the serum samples, the protein concentration remained steady throughout the experiment period. However, all the experimental fish displayed statistically high levels of lysozyme and protease activity, from 890 u/mL to 1220 u/mL, and 6.10 u/μL to 11.88 u/μL, respectively. In the whole blood samples, the haemoglobin content and the red blood cells (RBC) count did not show any significant change in any of the experimental groups. But, the percentage of lymphocytes showed a marginal increase from 0.47 to 0.6 in the experimental groups. Overall, the immune responses induced by L. cyprinacea protein extracts depicts a pattern of specific responses, in which the local humoral responses dominate the systemic humoral/cellular response. The results further revealed the possibility of futuristic approaches to control freshwater ectoparasites.

Immune-antioxidant trait, Aeromonas veronii resistance, growth, intestinal architecture, and splenic cytokines expression of Cyprinus carpio fed Prunus armeniaca kernel-enriched diets

Currently, the intervention of plant by-products in the fish diet has gained tremendous attention owing to the economic and high nutritious value. The current study is a pioneer attempt to incorporate the apricot, Prunus armeniaca kernel powder (PAKP) into the Common carp, Cyprinus carpio diets, and assess its efficacy on growth, digestion, intestinal morphology, immunity, antioxidant capacity, and splenic cytokines expression, besides the antibacterial role against Aeromonas veronii infection. Apparently healthy fish (N = 120) with an initial body weight of 24.76 ± 0.03g were allotted in 12 glass aquaria (60 L) and randomly distributed into four groups (triplicates, 10 fish/aquarium). The control group (PAKP0) was fed a basal diet without additives. The second, third, and fourth groups were provided PAKP diets with various concentrations (2.5 (PAKP2.5), 5 (PAKP5), and 10 g kg^-1 (PAKP10)) respectively. After 60 days (feeding trial), sub-samples of the fish (12 fish/group) were intraperitoneally injected with 1 × 10⁷ CFU mL^-1 of A. veronii. Results revealed that body weight gain, feed conversion ratio, and specific growth rates were significantly augmented in the PAKP10 group in comparison to the other groups. The dietary inclusion of PAKP at all concentrations boosted the digestive capacity and maintained the intestinal morphology (average villus length, villus width, and goblet cells count) with a marked improvement in PAKP10. Moreover, fish fed on PAKP10 followed by PAKP5 then PAKP2.5 diets had noticeably elevated values of immunological biomarkers (IgM, antiprotease, and lysozyme activity) and antioxidant capabilities (the total antioxidant capacity, superoxide dismutase, and reduced glutathione) as well as significant up-regulation of immune and antioxidant-related genes (TGF-β2, TLR-2, TNF-α, IL-10, SOD, GPx, and GSS). Fourteen days post-infection with A. veronii, the highest relative percentage survival of fish was observed in PAKP10 (83.33%), followed by PAKP5 (66.67%), and PAKP2.5 (50%). Our results indicated that a dietary intervention with PAKP could promise growth, digestion, immunity, and protect C. carpio against A. veronii infection in a dose-dependent manner. This offers a framework for future application of such seeds as a growth promotor, immune-stimulant, and antioxidant, besides an alternative cheap therapeutic antibacterial agent for sustaining the aquaculture industry.

Silica Nanoparticle Acute Toxicity on Male Rattus norvegicus Domestica: Ethological Behavior, Hematological Disorders, Biochemical Analyses, Hepato-Renal Function, and Antioxidant-Immune Response

With extensive production and various applications of silica nanoparticles (SiNPs), there is a controversy regarding the ecotoxicological impacts of SiNPs. Therefore, the current study was aimed to assess the acute toxicity of silica nanoparticles in male Rattus norvegicus domestica after 24 and 96 h. Hematological, serum biochemical, stress biomarker, and immune-antioxidant parameters were addressed. Chemical composition, crystal structure, and the particle shape and morphology of SiNPs were investigated using XRD, FTIR, BET, UV-Vis, and SEM, while TEM was used to estimate the average size distribution of particles. For the exposure experiment, 48 male rats were divided into four groups (12 rat/group) and gavaged daily with different levels of zero (control), 5, 10, and 20 mg of SiNPs corresponding to zero, 31.25, 62.5, and 125 mg per kg of body weight. Sampling was carried out after 24 and 96 h. Relative to the control group, the exposure to SiNPs induced clear behavioral changes such as inactivity, lethargy, aggressiveness, and screaming. In a dose-dependent manner, the behavior scores recorded the highest values. Pairwise comparisons with the control demonstrated a significant (p < 0.05) decrease in hematological and immunological biomarkers [lysozymes and alternative complement activity (ACH50)] with a concomitant reduction in the antioxidant enzymes [catalase (CAT), glutathione peroxidase (GPx), and superoxide dismutase (SOD)] in all exposed groups to SiNPs. On the contrary, there was a noticeable increase in biochemical parameters (glucose, cortisol, creatinine, urea, low-density lipoproteins (LDL), high-density lipoproteins (HDL), total protein, and albumin) and hepato-renal indicators, including alkaline phosphatase (ALP), alanine aminotransferase (ALT), and aspartate aminotransferase (AST), of all SiNP-exposed groups. It was observed that SiNPs induced acute toxicity, either after 24 h or 96 h, post-exposure of rats to SiNPs evidenced by ethological changes, hepato-renal dysfunction, hyperlipemia, and severe suppression in hematological, protein, stress, and immune-antioxidant biomarkers reflecting an impaired physiological status. The obtained outcomes create a foundation for future research to consider the acute toxicity of nanoparticles to preserve human health and sustain the environment.

Antimicrobial activity of chemically and biologically synthesized silver nanoparticles against some fish pathogens

Pathogens isolated from fish appear to possess considerable antimicrobial resistance and represent a problem for the economy and public health. Natural antimicrobial substitutes to traditional antibiotics represent an essential tool in the fight against antibiotic resistance. Nanotechnology has shown considerable potential in different research fields, and the antimicrobial properties of silver nanoparticles are known. Silver has been used for medical purposes since ancient times because of its bactericidal properties, and the highly reactive surfaces of silver nanoparticles (AgNPs) indicate that they might have a function in antimicrobial applications. This work aimed to study the antimicrobial properties of biologically produced AgNPs from Origanum vulgare leaves compared to chemically produced AgNPs. Both types were characterized by UV–vis spectrophotometry, TEM, and dynamic light scattering and tested against three bacterial strains (Streptococcus agalactiae, and Aeromonas hydrophila, both isolated from Nile tilapia and Vibrio alginolyticus, isolated from sea bass) and three fungal strains (Aspergillus flavus, Fusarium moniliforme, and Candida albicans, all isolated from Nile tilapia). Disk diffusion test and evaluation of ultrastructure changes of tested microorganisms treated with AgNPs by transmission electron microscopy were performed. Moreover, the hemolytic properties of AgNPs were studied on chicken and goat red blood cells. The results obtained declare that the green biological production of silver nanoparticles is safer and more effective than the chemical one; moreover, AgNPs have interesting dose-dependent antimicrobial properties, with better results for biologically produced ones; their effectiveness against tested bacterial and fungal strains opens the way to their use to limit fish diseases, increase economy and improve human health.

Assessing Fish Immunotoxicity by Means of In Vitro Assays: Are We There Yet?

There is growing awareness that a range of environmental chemicals target the immune system of fish and may compromise the resistance towards infectious pathogens. Existing concepts to assess chemical hazards to fish, however, do not consider immunotoxicity. Over recent years, the application of in vitro assays for ecotoxicological hazard assessment has gained momentum, what leads to the question whether in vitro assays using piscine immune cells might be suitable to evaluate immunotoxic potentials of environmental chemicals to fish. In vitro systems using primary immune cells or immune cells lines have been established from a wide array of fish species and basically from all immune tissues, and in principal these assays should be able to detect chemical impacts on diverse immune functions. In fact, in vitro assays were found to be a valuable tool in investigating the mechanisms and modes of action through which environmental agents interfere with immune cell functions. However, at the current state of knowledge the usefulness of these assays for immunotoxicity screening in the context of chemical hazard assessment appears questionable. This is mainly due to a lack of assay standardization, and an insufficient knowledge of assay performance with respect to false positive or false negative signals for the different toxicant groups and different immune functions. Also the predictivity of the in vitro immunotoxicity assays for the in vivo immunotoxic response of fishes is uncertain. In conclusion, the currently available database is too limited to support the routine application of piscine in vitro assays as screening tool for assessing immunotoxic potentials of environmental chemicals to fish.

The Dietary Effects of Nutmeg (Myristica fragrans) Extract on Growth, Hematological Parameters, Immunity, Antioxidant Status, and Disease Resistance of Common Carp (Cyprinus carpio) against Aeromonas hydrophila

Medicinal plants are increasingly used in aquaculture owing to their beneficial impacts on the health status of farmed fish. The current study was conducted to investigate the effect of nutmeg (Myristica fragrans) extract on growth, immunity, antioxidant parameters, and resistance of common carp (Cyprinus carpio) against Aeromonas hydrophila. In addition, in vitro antibacterial activity of the skin mucus of fish fed on nutmeg extract was evaluated against three major fish pathogenic bacteria through the standard disk diffusion method. Fish (17.27 ± 0.11 g) were divided into four groups and fed on experimental diets containing different levels of nutmeg extract, including zero (control), 0.5% (M1), 1% (M2), and 2% (M3) per kg diet. Results showed that nutmeg significantly enhanced growth parameters after a four-week feeding trial. Feed conversion ratio was remarkably reduced with the lowest value reported for the M3 group, whereas weight gain was notably increased in M2 and M3. No significant effect was found on the hematological profile, including mean corpuscular hemoglobin concentration, mean corpuscular hemoglobin, mean corpuscular volume, and hematocrit, while the highest levels of red blood cells and white blood cells were found in the M3 group. Stress biomarkers, including glucose and cortisol, were the lowest in the M3 group. Serum and skin mucus immunological and antioxidant parameters were significantly higher in M3, followed by M2, where the highest resistance was also observed. In addition, skin mucus samples effectively inhibited Streptococcus iniae, Yersinia ruckeri, and Aeromonas hydrophila. Overall, the present results suggest that dietary nutmeg (20 g/kg diet) could be used as a growth promotor and immunostimulant in common carp.

Effects of short-term selenium exposure on respiratory activity and proximate body composition of early-life stages of Catla catla, Labeo rohita and Cirrhinus mrigala

Metal exposure impairs respiration, increases metabolic demand, and reduces energy storage/fitness in aquatic species. Respiratory impairment and energy storage was examined in acute selenium-exposed Indian major carps, Catla catla, Labeo rohita and Cirrhinus mrigala fry and were correlated with exposure concentrations. Toxicity effects were determined in a renewal bioassay using 96 h lethal selenium concentrations. Species sensitivity distribution (SSD) was also used to derive predicted no-effect concentrations, toxicity exposure ratios, for selenium exposures to early-life fish stages. Mortality was proportional with increasing concentrations. Oxygen consumption and lipid content compared to moisture and ash and of all protein content in tissues of C. catla and C. mrigala indicates that lowered oxygen consumption is directly predictive of lowered lipid content and selenium-induced hypoxia impacts the energy/nutritional status of the early-life stage of carp. This cross-taxa comparison will have major implications for advancing impact assessment and allow better targeting of species for conservation measures.

Ecotoxicological Effects of Silver Nanoparticles (Ag-NPs) on Parturition Time, Survival Rate, Reproductive Success and Blood Parameters of Adult Common Molly (Poecilia sphenops) and Their Larvae

Nanoparticles (NPs) can display toxicological effects on aquatic organisms. This study investigates ecotoxicological effects of Ag-NPs on reproductive and blood parameters of adult common molly (Poecilia sphenops) and their larvae. During the LC50 96 h test, female fish were exposed to concentrations of 0, 5, 15, 25, 35, 45 and 60 mg L−1 of Ag-NPs, while larvae were exposed to 0, 3, 5, 10 and 15 mg L−1. Finally, we aim to evaluate the effects of 0, 5, 10 and 15 mg L−1 of Ag-NPs on parturition time, reproductive success and hematological parameters of the mature fish exposed to sub-lethal concentration during a 62-day period. We also evaluated the survival rate of larvae. The results show a positive correlation between mortality rate and Ag-NP concentration. Values for LC50 96 h in adult fish and larvae were 26.85 mg L−1 and 6.22 mg L−1, respectively. A lack of parturition and reproductive success were seen in fish that underwent chronic exposure to Ag-NPs (15 mg L−1). The results show that RBC, WBC and hematocrit were significantly decreased in fish exposed to Ag-NPs. In addition, the serum concentrations of total protein, albumin, cholesterol and triglycerides were significantly increased in fish submitted to Ag-NPs (concentrations of 5–15). In conclusion, submitting a fish to higher concentration than 10 mg L−1 has adverse effects on reproductive system and blood parameters.

Nano-silica and magnetized-silica mitigated lead toxicity: Their efficacy on bioaccumulation risk, performance, and apoptotic targeted genes in Nile tilapia (Oreochromis niloticus)

Contamination of aquatic systems with heavy metals (HM) is of great concern owing to their deleterious impact on living organism. The current research is focused on application of silica particles with new functionalized properties (magnetic silica; SiMag or Nanoporous silica; SiNPs) and their efficacy to mitigate lead (pb) toxicity in Nile tilapia. One thousand fingerlings were distributed: two control groups (negative; without pb toxicity (NC) positive (with pb toxicity) and other four groups received two silica sources (SiMag or SiNPs) with two levels (400 and 600 mg/kg diet) for 56 days then exposed to pb for 30 days. Before toxicity exposure, maximum growth, and most improved feed conversion ratio and biochemical parameters were noticed with higher SiMag or SiNPs levels. Serum antioxidant enzymes and their transcriptional levels in muscle and liver were boosted in groups received SiMag or SiNPs. After toxicity exposure, hematological and antioxidants biomarkers maintained at adequate levels in SiMag or SiNPs. Prominent reduction of residual pb in gills, liver, kidney, and muscle was observed in SiNPs then SiMag groups. Interestingly, the maximum down-regulation of P450, caspase-3 and HSP-70 and MT were observed in groups received 600 mg/kg diet of SiMag or SiNPs. The higher level of P53 in liver and gills was detected in PC, inversely reduced in SiMag or SiNPs. Severity of the histopathological alterations in examined organs greatly reduced in groups received SiMag or SiNPs, unlike it were induced in PC group. In conclusion, higher SiMag or SiNPs levels not only mitigate negatives impact of pb toxicity in fish but also ensure its safety for human consumption.

Imperative role of electron microscopy in toxicity assessment: A review

Electron microscope (EM) was developed in 1931 and since then microscopical examination of both the biological and non-biological samples has been revolutionized. Modifications in electron microscopy techniques, such as scanning EM and transmission EM, have widened their applicability in the various sectors such as understanding of drug toxicity, development of mechanism, criminal site investigation, and characterization of the nano-molecule. The present review summarizes its role in important aspects such as toxicity assessment and disease diagnosis in special reference to SARS-COV2. In the biological system, EM studies have elucidated the impact of toxicants at the ultra-structural level in various tissue in conformity to physiological alterations. Thus, EM can be concluded as an important tool in toxicity assessment and disease prognosis.

Effects of sodium butyrate nanoparticles on the hemato-immunological indices, hepatic antioxidant capacity, and gene expression responses in Oreochromisniloticus

Recently, nanotechnology has been greatly developed to provide the aquaculture industry with new beneficial nanomaterials to improve the health and welfare of aquatic animals. Herein, an eight-week experiment was designed to examine the dietary impacts of sodium butyrate nanoparticles (SB-NPs) on the hematological profile, blood proteins, immunological indices, antioxidant capacity, and expression analysis of cytokines and antioxidant-related genes in Oreochromis niloticus. Fish were randomly assigned into 5 experimental groups (3 replicates per group) and were fed diets supplemented with 5 levels of SB-NPs as 0.0 (control), 0.5, 1.0, 1.5, and 2.0 mg kg^-1. The results revealed that supplementing diets with SB-NPs (1.0-2.0 mg kg^-1) significantly elevated erythrocyte and leukocyte counts, hemoglobin concentrations, hematocrit values, total albumin, globulin, serum lysozyme activities, and total immunoglobulin M values compared with the control group. Notably, the highest levels of the parameters mentioned above were noticed in the group fed diet supplemented with 1.5 mg kg^-1 SB-NPs. Moreover, dietary SB-NPs modulated the fish's antioxidant defense mechanisms, whereas there was a significant increase in hepatic superoxide dismutase, catalase, and glutathione peroxidase enzyme activities along with a significant decline in hepatic malondialdehyde concentrations in fish groups fed diets supplemented with SB-NPs (1.0-2.0 mg kg^-1). A significant upregulation of antioxidant enzyme genes (gpx and sod), anti-inflammatory cytokine (il-10), and pro-inflammatory cytokines (il-1β and il-8) were noticed in liver tissues of SB-NPs groups (0.5-1.5 mg kg^-1). The highest mRNA expression folds of the above genes were recorded in the fish group fed diet supplemented with 1.5 mg kg^-1 SB-NPs. In this context, we hypothesized that dietary supplementation with SB-NPs can boost the antioxidant status and immunity of O. niloticus. However, further research studies are still recommended.

Antioxidant and antigenotoxic potential of Morinda tinctoria Roxb. leaf extract succeeding cadmium exposure in Asian catfish, Pangasius sutchi

The present study investigated the protective effect of methanolic leaf extract of Morinda tinctoria. Roxb (MEMT) (200 mg/kg) via feed in supplementation with standard compound silymarin (400 mg/kg). M. tinctoria (Roxb.) belonging to Rubiaceae, is an evergreen shrub indigenous to unfarmed lands of tropical countries. It is considered as an essential traditional medicine attributing for the potential antioxidant and anti-inflammatory properties. The enhancements of antioxidant and antigenotoxic status in different tissues of cadmium (Cd) intoxicated Pangasius sutchi were evaluated by using various antioxidant assays (superoxide dismutase (SOD) and catalase (CAT) and lipid peroxidation) in addition to micronuclei (MN), binuclei (BN) and comet assay. The cadmium toxicated fish showed a significant (p < 0.001) increase in lipid peroxidation (LPO) activities in liver, gills, muscle and kidney whereas significant (p < 0.001) decline were observed in superoxide dismutase (SOD) and catalase (CAT) contents in all fish tissues. The results also revealed that, Cd exposure induced the formation of genotoxic endpoints like MN, BN, notched nuclei, kidney shaped nuclei and DNA damage in the fish erythrocytes. Maximum of 26.8% MN frequencies and maximum of 66.74% tail DNA damage were observed on the 7th day of Cd exposure. A time-dependent significant increase (p < 0.001) in the frequencies of MN, BN and tail DNA damage were observed in all treated groups against the control which started to decline from 14th day onwards. There was a decline in the LPO content, frequencies of MN, BN and percentage of tail DNA in contrast to significant elevation in SOD and CAT content in all tissues due to the combined treatment of M. tinctoria feed and water borne Cd exposure. It can be concluded from our observations that, supplementation of M. tinctoria leaf extract through feed alone produced enhanced antioxidant and antigenotoxic status in cadmium treated fish by diminishing oxidative stress and genotoxicity effects in a time dependent manner.

The protective role of vitamins (E + C) on Nile tilapia (Oreochromis niloticus) exposed to ZnO NPs and Zn ions: Bioaccumulation and proximate chemical composition

The accumulation potency of zinc nanoparticles in Nile tilapia (Oreochromis niloticus) were previously studied but their impacts on proximate chemical composition in muscle tissue by describing the dose-dependent accumulation and the protective role of vitamins (E + C), have not been investigated. Therefore, this study was carried out to assess the protective role of vitamins (E + C) on Zn accumulation in muscle and gill tissues of O. niloticus exposed to three sublethal concentrations (1/8 LC50, 1/4 LC50, and 1/2 LC50) of zinc oxide nanoparticles (ZnO NPs) compared to zinc oxide bulk particles (ZnO BPs) as well as their effects on the induced chemical composition alterations for different experimental periods (7, 14, 21, and 28 day). The data displayed that fish exposed to the different sublethal concentrations of ZnO NPs or ZnO BPs have a significant increase (p<0.05) in Zn ions accumulation in muscle and gill tissues compared to control group but Zn was accumulated in gill tissue higher than muscle tissue at all exposure periods. Also, Zn accumulation was higher in fish tissues exposed to ZnO NPs than ZnO BPs. On the other hand, groups supplemented with vitamins (E + C) showed a significant decreasing (p<0.05) in accumulated Zn levels compared to groups without supplementation. The values of these supplemented groups returned to similar levels established in the control at low concentrations but still higher than control at the high concentrations. Furthermore, the results showed that moisture and ash content slightly increased while protein and fat decreased in fish exposed to ZnO NPs or ZnO BPs compared to control group. In conclusion, the findings supported that a combination of vitamins (E + C) reduced Zn accumulation and ameliorated chemical composition alterations in O.niloticus fish.

Adsorptivity of mercury on magnetite nano-particles and their influences on growth, economical, hemato-biochemical, histological parameters and bioaccumulation in Nile tilapia (Oreochromis niloticus)

Among toxic pollutants, Mercury (Hg) is a toxic heavy metal that induces harmful impacts on aquatic ecosystems directly and human being's health indirectly. This study confirmed the in vitro magnetic potential of magnetite Nano-Particles (Fe₃O₄ NPs) against waterborne Hg exposure-induced toxicity in Nile tilapia (Oreochromis niloticus). We further evaluate the safety profile of Fe₃O₄ NPs on fish growth, hemato-biochemical, histological parameters, bioaccumulation in muscles, and economy. Magnetite nanoparticles were characterized, adsorption loading to Hg ions was investigated, and testing different concentrations of Fe₃O₄ NPs (0.2, 0.4, 0.6, 0.8, and 1.0 mg/L) was applied to determine the highest concentration of adsorption. An in vivo experiment includes 120 fish with an average weight of 26.2 ± 0.26 g were randomly divided into 4 equal groups, each group had three replicates (n = 30 fish/group; 10 fish/ replicate). All groups were fed on a reference basal diet and the experiment was conducted for 30 days. The first group (G₁) was allocated as a control. The second group (G₂) received 1.0 mg/L aqueous suspension of Fe₃O₄ NPs. The third group (G₃) was exposed to an aqueous solution of Hg ions at a concentration of 0.025 mg/L. Meanwhile, the fourth group (G₄) acquired an aqueous suspension composed of a mixture of Hg ions and Fe₃O₄ NPs as previously mentioned. Throughout the exposure period, the clinical signs, symptoms, and mortalities were recorded. The Hg ions-exposed group induced the following consequences; reduced appetite resulting in reduced growth and less economic efficiency; microcytic hypochromic anemia, leukocytosis, lymphopenia, and neutrophilia; sharp and clear depletion in the immune indicators including lysozymes activity, immunoglobulin M (IgM), and Myeloperoxidase activities (MPO); significant higher levels of ALT, AST, urea, creatinine, and Superoxide dismutase (SOD); histological alterations of gill, hepatic and muscular tissues with strong expression of apoptotic marker (caspase 3); and a higher accumulation of Hg ions in the muscles. Surprisingly, Fe₃O₄ NPs-supplemented groups exhibited strong adsorption capacity against the Hg ions and mostly removed the Hg ions accumulation in the muscles. Also, the hematological, biochemical, and histological parameters were recovered. Thus, in order to assess the antitoxic role of Fe₃O₄ NPs against Hg and their safety on O. niloticus, and fill the gap of the research, the current context was investigated to evaluate the promising role of Fe₃O₄ NPs to prevent Hg-exposure-induced toxicity and protection of fish health, which ascertains essentiality for sustainable development of nanotechnology in the aquatic environment.