Oxidative Stress in the Muscles of the Fish Nile Tilapia Caused by Zinc Oxide Nanoparticles and Its Modulation by Vitamins C and E

Comparative Toxicity of TiO2 and Sn-Doped TiO2 Nanoparticles in Zebrafish After Acute and Chronic Exposure

This study was conducted to assess the toxicological potential of synthesized pure and Sn-doped TiO2 NPs (Sn-TiO2 NPs) in zebrafish after acute and chronic exposure. The pure TiO2 NPs, 4%, and 8% Sn-TiO2 NPs were synthesized and characterized using X-ray diffraction, Scanning Electron Microscope, diffuse reflectance spectra, dynamic light scattering, and zeta potential analyses. The pure TiO2 NPs, 4%, and 8% Sn-TiO2 NPs were spherical with average sizes of about 40, 28, and 21 nm, respectively, indicating significant size reduction of TiO2 NPs following Sn doping. According to our results, the LC50-96h increased in the order of 8% Sn-TiO2 NPs (45 mg L-1) < 4% Sn-TiO2 NPs (80.14 mg L-1) < pure TiO2 NPs (105.47 mg L-1), respectively. Exposure of fish to Sn-TiO2 NPs after 30 days resulted in more severe histopathological alterations in gills, liver, intestine, and kidneys than pure TiO2 NPs. Furthermore, Sn-doping significantly elevated malondialdehyde levels and micronuclei frequency, indicating increased oxidative stress and genotoxicity. Expression analysis revealed altered expression of various genes, including upregulation of pro-apoptotic Bax gene and downregulation of anti-apoptotic Bcl-2 gene, suggesting potential induction of apoptosis in response to Sn-doped NPs. Additionally, antioxidant genes (Gpx, Sod, Cat, and Ucp-2) and stress response gene (Hsp70) showed altered expression, suggesting complex cellular responses to mitigate the toxic effects. Overall, this study highlights the concerning impact of Sn-doping on the toxicity of TiO2 NPs in zebrafish and emphasizes the need for further research to elucidate the exact mechanisms underlying this enhanced toxicity.

Toxicity of zinc oxide nanoparticles: Cellular and behavioural effects

Due to their extensive use, the release of zinc oxide nanoparticles (ZnO NP) into the environment is increasing and may lead to unintended risk to both human health and ecosystems. Access of ZnO NP to the brain has been demonstrated, so their potential toxicity on the nervous system is a matter of particular concern. Although evaluation of ZnO NP toxicity has been reported in several previous studies, the specific effects on the nervous system are not completely understood and, particularly, effects on genetic material and on organism behaviour are poorly addressed. We evaluated the potential toxic effects of ZnO NP in vitro and in vivo, and the role of zinc ions (Zn2+) in these effects. In vitro, the ability of ZnO NP to be internalized by A172 glial cells was verified, and the cytotoxic and genotoxic effects of ZnO NP or the released Zn2+ ions were addressed by means of vital dye exclusion and comet assay, respectively. In vivo, behavioural alterations were evaluated in zebrafish embryos using a total locomotion assay. ZnO NP induced decreases in viability of A172 cells after 24 h of exposure and genetic damage after 3 and 24 h. The involvement of the Zn2+ ions released from the NP in genotoxicity was confirmed. ZnO NP exposure also resulted in decreased locomotor activity of zebrafish embryos, with a clear role of released Zn2+ ions in this effect. These findings support the toxic potential of ZnO NP showing, for the first time, genetic effects on glial cells and proving the intervention of Zn2+ ions.

Antioxidant-related enzymes and peptides as biomarkers of metallic nanoparticles (eco)toxicity in the aquatic environment

Increased awareness of the impact of human activities on the environment has emerged in recent decades. One significant global environmental and human health issue is the development of materials that could potentially have negative effects. These materials can accumulate in the environment, infiltrate organisms, and move up the food chain, causing toxic effects at various levels. Therefore, it is crucial to assess materials comprising nano-scale particles due to the rapid expansion of nanotechnology. The aquatic environment, particularly vulnerable to waste pollution, demands attention. This review provides an overview of the behavior and fate of metallic nanoparticles (NPs) in the aquatic environment. It focuses on recent studies investigating the toxicity of different metallic NPs on aquatic organisms, with a specific emphasis on thiol-biomarkers of oxidative stress such as glutathione, thiol- and related-enzymes, and metallothionein. Additionally, the selection of suitable measurement methods for monitoring thiol-biomarkers in NPs' ecotoxicity assessments is discussed. The review also describes the analytical techniques employed for determining levels of oxidative stress biomarkers.

The probiotic SLAB51 as agent to counteract BPA toxicity on zebrafish gut microbiota -liver-brain axis

A plethora of studies have so far described the toxic effects of bisphenol A (BPA) on organism health, highlighting the urgent need to find new strategies not only to reduce the presence of this toxicant but also to counteract its adverse effects. In this context, probiotics emerged as a potential tool since they promote organism welfare. Using a multidisciplinary approach, this study explores the effects of SLAB51 dietary administration to counteract BPA toxicity using zebrafish as a model. Adult males and females were maintained under standard conditions (control group; C), exposed for 28 days via the water to an environmental relevant dose of BPA (10 μg/L; BPA), dietary treated with SLAB51 (109 CFU/g of body weight; P) and co-treated with BPA plus SLAB51 (BPA + P). In the gut, exposure to BPA resulted in altered architecture in both males and females, with females also experiencing an increase of pathogenic bacterial species. Co-administration of BPA + P led to the restoration of normal gut architecture, favored beneficial bacteria colonization, and decreased the abundance of pathogenic species. In the liver, male BPA exposure led to steatosis and glycogen depletion, which was partially mitigated by SLAB51 co-administration. In contrast, in females exposed to BPA, the lack of steatosis along with the greater glycogen depletion, suggested an increase in energy demand as supported by the metabolomic phenotype. The analysis of liver metabolites in BPA + P males revealed increased levels of anserine and reduced levels of glutamine, which could lie behind the counteraction of the brain histopathological damage caused by BPA. In BPA + P females, a reduction of retinoic acid was found in the liver, suggesting an increase in retinoids responsible for BPA detoxification. Overall, these results demonstrate that SLAB51 exerts its beneficial effects on the gut microbiota-brain-liver axis through distinct molecular pathways, effectively mitigating the pleiotropic toxicity of BPA.

In Vitro Efficacy of Isobutyl Cyanoacrylate Nanoparticles against Fish Bacterial Pathogens and Selection Preference by Rainbow Trout (Oncorhynchus mykiss)

The upsurge in havoc being wreaked by antibiotic-resistant bacteria has led to an urgent need for efficacious alternatives to antibiotics. This study assessed the antibacterial efficacy of two isobutyl cyanoacrylate nanoparticles (iBCA-NPs), D6O and NP30, against major bacterial pathogens of fish. In vivo tests on rainbow trout were preceded by in vitro tests of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). NP30 exhibited higher efficacy than D60, but both iBCA-NPs demonstrated dose-dependent and species-specific in vitro antibacterial properties against the bacterial isolates. Generally, Gram-negative bacteria were more resistant to the iBCA-NPs. Streptococcus iniae, Tenacibaculum maritimum, and Photobacterium damselae were particularly sensitive to both iBCA-NPs. Administered to rainbow trout at 3571.4 mg (iBCA-NP)/kg feed, the iBCA-NPs produced a relative gain rate and survival rates comparable to the control (p > 0.05). The condition factor and the hepatosomatic and viscerosomatic indices of fish were indifferentiable (p > 0.05) between the iBCA-NP groups and the control. The iBCA-NPs caused no alteration in stress, oxidative stress (superoxide dismutase, SOD), plasma complement titer, or lysozyme activity. This study presents the first report of antibacterial activity of iBCA-NPs against Gram-negative bacteria. The results of this study suggest that D60 and NP30 may contribute to reducing the amounts of antibiotics and chemotherapeutic agents used in aquaculture.

Toxic and bioaccumulative effects of zinc nanoparticle exposure to goldfish, Carassius auratus (Linnaeus, 1758)

The widespread use of produced metal oxide nanoparticles (NPs) has increased major concerns about their impact on human as well as aquatic animal health. The present study shows that exposure to different concentrations of zinc oxide (ZnO) NPs led to high accumulations of Zn ions in the metabolic organs of fish (liver and gills), resulting in severe oxidative stress in Carassius auratus. The goldfish (C. auratus) was chosen as an aquatic species for the evaluation of the potential toxicity of aqueous ZnO-NPs (Treatments of hemoglobin and neutrophils (0, 0.5, 1, and 1.5 mg L- 1) following 14 days of exposure. A range of histological and hematological factors were examined. Exposure to the NPs produced significant reduction of red blood cell and white blood cell counts, hematocrit) were found to produce no significant differences in lymphocyte, monocyte, and eosinophil counts; as well as the mean corpuscular hemoglobin concentrations index (P > 0.05). Moreover, the results revealed significant alterations in serum biochemical parameters, hepatic enzyme levels, and immune and antioxidant responses; except for total protein and superoxide dismutase (SOD) of C. auratus exposed to ZnO-NPs, particularly at the 1 and 1.5 mg L- 1 concentrations. Fish exposed to 1 and 1.5 mg L-1 ZnO-NPs displayed a significant reduction in alternative complement pathway activity, lysozyme, and total protein contents of mucus compared to those in the control group. The results showed that hepatic SOD and catalase, and gill catalase activity were significantly decreased, and their malondialdehyde levels increased at 1 and 1.5 mg L-1 ZnO-NPs compared to the control group (P < 0.05). Significant accumulations of ZnO-NPs were observed in the liver, kidney, and gill tissues of fish leading to severe histopathological alterations in these organs. These results suggest that water-borne ZnO-NPs can easily accumulate in metabolic organs and lead to oxidative stress and destructive effects on the physiological features of C. auratus.

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.

Modulatory effect of thymol on the immune response and susceptibility to Aeromonas hydrophila infection in Nile tilapia fish exposed to zinc oxide nanoparticles

Zinc oxide nanoparticles (ZnO-NPs) have many exciting properties that make their use in a continuous increase in various biomedical, industrial, and agricultural applications. This is associated with accumulation in the aquatic ecosystems and fish exposure with consequent deleterious effects. To determine the potential of thymol to counteract the immunotoxic effects of ZnO-NPs, Oreochromis niloticus was exposed to ZnO-NPs (⅕ LC₅₀ =1.14 mg/L, for 28 days) with or without feeding a thymol-incorporated diet (1 or 2 g/kg diet). Our data demonstrated a reduction of aquaria water quality, leukopenia, and lymphopenia with a decrease in serum total protein, albumin, and globulin levels in exposed fish. At the same time, the stress indices (cortisol and glucose) were elevated in response to ZnO-NPs exposure. The exposed fish also revealed a decline in serum immunoglobulins, nitric oxide, and the activities of lysozyme and myeloperoxidase, in addition to reduced resistance to the Aeromonas hydrophila challenge. The RT-PCR analysis showed downregulation of antioxidant (SOD) superoxide dismutase and (CAT) catalase gene expression in the liver tissue with overexpression of the immune-related genes (TNF-α and IL-1β). Importantly, we found that thymol markedly protected against ZnO-NPs-induced immunotoxicity in fish co-supplemented with thymol (1 or 2 g/kg diet) in a dose-dependent manner. Our data confirm the immunoprotective and antibacterial effects of thymol in ZnO-NPs exposed fish, supporting the potential utility of thymol as a possible immunostimulant agent.

Accumulation, Chronicity, and Induction of Oxidative Stress Regulating Genes Through Allium cepa L. Functionalized Silver Nanoparticles in Freshwater Common Carp (Cyprinus carpio)

Green evolutionary products such as biologically fabricated nanoparticles (NPs) pose a hazard to aquatic creatures. Herein, biogenic silver nanoparticles (AgNPs) were synthesized by the reaction between ionic silver (AgNO₃) and aqueous onion peel extract (Allium cepa L). The synthesized biogenic AgNPs were characterized with UV-Visible spectrophotometer, XRD, FT-IR, and TEM with EDS analysis; then, their toxicity was assessed on common carp fish (Cyprinus carpio) using biomarkers of haematological alterations, oxidative stress, histological changes, differential gene expression patterns, and bioaccumulation. The 96 h lethal toxicity was analysed with various concentrations (2, 4, 6, 8, and 10 mg/l) of biogenic AgNPs. Based on 96 h LC₅₀, sublethal concentrations (1/15^th, 1/10^th, and 1/5^th) were given to C. carpio for 28 days. At the end of experiment, the bioaccumulations of Ag content were accumulated mainly in the gills, followed by the liver and muscle. At an interval of 7 days, the haematological alterations showed significance (p < 0.05) and elevation of antioxidant defence mechanism reveals the toxicity of biogenic synthesized AgNPs. Adverse effects on oxidative stress were probably related to the histopathological damage of its vital organs like gill, liver, and muscle. Finally, the fish treated with biogenic synthesized AgNPs were significantly (p < 0.05) downregulates the oxidative stress genes such as Cu-Zn SOD, CAT, GPx1a, GST-α, CYP1A, and Nrf-2 expression patterns. The present study provides evidence of biogenic synthesized AgNPs influence on the aquatic life through induction of oxidative stress.

Assessment of multiple biomarkers in Lithobates catesbeianus (Anura: Ranidae) tadpoles exposed to zinc oxide nanoparticles and zinc chloride: integrating morphological and behavioral approaches to ecotoxicology

The ecotoxicological risk to vertebrates posed by zinc oxide nanoparticles (ZnO NPs) is still poorly understood, especially in animals with a biphasic life cycle, which have aquatic and terrestrial phases, such as amphibians. In the present study, we investigated whether acute exposure (7 days) to ZnO NPs and zinc chloride (ZnCl₂) at three environmentally relevant concentrations (0.1, 1.0, and 10 mg L^-1) induces changes in the morphology, chondrocranium, and behavior of the tadpoles of Lithobates catesbeianus (Anura: Ranidae). Tadpoles exposed to both forms of Zn did not undergo any morphological or behavioral changes at the lowest concentrations (0.1 and 1.0 mg L^-1). However, the animals exposed to the highest concentration (10 mg L^-1) lacked oral disc structures, were smaller in size, had a longer tail, and presented changes in the position and coiling of the intestine and malformations of the chondrocranium in comparison with the control group. This indicates that ZnO NPs and ZnCl₂ altered the development of the tadpoles, causing delays in their metamorphosis and even reducing individual fitness. The tadpoles exposed to both forms of Zn at 10 mg L^-1 also had reduced mobility, especially in the presence of conspecifics. Based on these findings, we emphasize the importance of studying morphological, skeletal, and behavioral biomarkers to evaluate the toxic effects of metal-based nanoparticles in amphibians.

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.

Dietary exposure of zinc oxide nanoparticles (ZnO-NPs) from canned seafood by single particle ICP-MS: Balancing of risks and benefits for human health

The present study aims to give information regarding the quantification of ZnO-NPs in canned seafood, which may be intentionally or unintentionally added, and to provide a first esteem of dietary exposure. Samples were subjected to an alkaline digestion and assessment of ZnO-NPs was performed by the single particle ICP-MS technique. ZnO-NPs were found with concentrations range from 0.003 to 0.010 mg/kg and a size mean range from 61.3 and 78.6 nm. It was not observed a clear bioaccumulation trend according to trophic level and size of seafood species, although the mollusk species has slightly higher concentrations and larger size. The number of ZnO-NPs/g does not differ significantly among food samples, observing an average range of 5.51 × 10⁶ - 9.97 × 10⁶. Dissolved Zn determined with spICP-MS revealed comparable concentration to total Zn determined with ICP-MS in standard mode, confirming the efficiency of alkaline digestion on the extraction of the Zn. The same accumulation trend found for ZnO-NPs was observed more clearly for dissolved Zn. The ZnO-NPs intake derived from a meal does not differ significantly among seafood products and it ranges from 0.010 to 0.031 µg/kg b.w. in adult, and from 0.022 to 0.067 µg/kg b.w. in child. Conversely, the intake of dissolved Zn is significantly higher if it is assumed a meal of mollusks versus the fish products, with values of 109.3 µg/kg b.w. for adult and 240.1 µg/kg b.w. for child. Our findings revealed that ZnO-NPs have the potential to bioaccumulate in marine organisms, and seafood could be an important uptake route of ZnO-NPs. These results could be a first important step to understand the ZnO-NPs human dietary exposure, but the characterization and quantification of ZnO-NPs is necessary for a large number of food items.

Modulatory effect of dietary copper nanoparticles and vitamin C supplementations on growth performance, hematological and immune parameters, oxidative status, histology, and disease resistance against Yersinia ruckeri in rainbow trout (Oncorhynchus mykiss)

Copper and vitamin C are micronutrients needed for the living organism's functions. Vitamin C has a great effect on the immune system of fish. The present study aimed to evaluate the effects of dietary copper nanoparticles (Cu-NPs) and vitamin C (VC) supplementations on rainbow trout (Oncorhynchus mykiss) juveniles. So, 216 rainbow trout juveniles were randomly assigned to six groups with trial diets supplemented with Cu-NPs and VC including 0/0 (T1, control diet), 0/250 (T2), 0/500 (T3), 2/250 (T4), 2/500 (T5), and 2/0 (T6) mg Cu-NPs/VC per kg diet. After the feeding trial for 60 days, the fish were challenged with Yersinia ruckeri, and the survival rate was calculated for 15 days. Based on the data analysis, weight gain (WG), specific growth rate (SGR), protein efficiency ratio (PER), lysozyme, alternative complement activity (ACH50), hematocrit (Hct), hemoglobin (Hb), and mean corpuscular volume (MCV) were significantly (p < 0.05) increased in the fish fed on T4 and T5 diets compared with the control group. Catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPX) were significantly (p < 0.05) decreased in the fish fed with diets contain Cu-NPs and VC (T4 and T5). The expressions of TNF-α, IL-1ß, IL-10, SOD, CAT, and GPX genes were significantly (p < 0.05) decreased in the fish fed on T3, T4, and T5 diets versus the control. In addition, the dietary Cu-NPs and VC supplementations significantly enhanced resistance against pathogens and led to the control of infection in rainbow trout. In conclusion, Cu-NPs and VC administered as feed additives at 2/250-500 mg/kg elevated the growth performance, antioxidant capacity, and health of rainbow trout.

Ameliorative role of ascorbic acid on the oxidative stress and genotoxicity induced by acetamiprid in Nile tilapia (Oreochromis niloticus)

On juveniles of Oreochromis niloticus, the protective potential of ascorbic acid (Asc) against oxidative stress and genotoxicity induced by acetamiprid (Aceta) sub-lethal concentrations was investigated in this study. Fishes were divided into six groups and exposed to either Asc (50 ppm), 10 and 20 ppm Aceta, 10 ppm (Aceta)+Asc, 20 ppm (Aceta)+Asc, or the unexposed control group. Superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX) activities and their transcripts were assessed. DNA damage in erythrocytes, hepatocytes, and gill cells, in addition to the mitotic index (MI), and the existence of erythrocytic nuclear abnormalities (ENAs) were performed. The results showed that concentrations of Aceta (10 and 20 ppm) induced oxidative stress by altering the antioxidant enzyme activities and transcripts. There were genotoxic effects of Aceta exposure showed by the significant (P < 0.05) increase in DNA-damaged cells and ENA, meanwhile a decrease in MI. Co-exposure with Asc showed significant alleviations of oxidative status and genotoxicity. Thus, results suggest that Asc-combined exposure could be the effective treatment against Aceta-induced oxidative stress accompanied with genotoxicity in O. niloticus.

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.

Assessment the using of silica nanoparticles (SiO2NPs) biosynthesized from rice husks by Trichoderma harzianum MF780864 as water lead adsorbent for immune status of Nile tilapia (Oreochromis niloticus)

Rice husks (RHs) was used as a substrate for biosynthesis of high-value Silica nanoparticles (SiO₂NPs). An isolate of Trichoderma harzianum MF780864 (T. harzianum) was isolated and identified based on the Internal Transcribed Spacers (ITS) sequences; it showed the potentiality to induce SiO₂NPs in the process of RHs biotransformation. SiO₂NPs were produced extracellularly and their size was of about 89 nm. SiO₂NPs characterized by oval, rod and cubical particles by using Transmission Electron Microscope (TEM).The Fourier transform infrared spectroscopy (FTIR) confirmed the presence of various functional groups of biomolecules and capping protein, encapsulating SiO₂NPs. Water and fish samples were collected from private fish farms in El-Sharkia Governorate, Egypt. Lead (Pb) was detected from water and fish samples at its highest concentration at about 0.088 mg/L. The adsorption capacity of Pb by SiO₂NPs was evaluated by testing different concentrations of SiO₂NPs viz. 1, 2, and 3 mg/L, wherein 1 mg/L revealed the highest Pb adsorption efficiency. Within laboratory trials, the results indicated that highest Pb adsorption efficiency revealed through the increasing of SiO₂NPs concentrations until 120 h. In vivo trial that lasted for 8 weeks, Nile tilapia (Oreochromis niloticus) (29.78 ± 0.36 g body weight) supplemented with 0.088 mg/L Pb was divided into four experimental groups having three replicates (15 fish/replicate; 45 fish/group). The results showed that SiO₂NPs supplementation through water revealed significant increase in growth and hematological parameters of O. niloticus. Moreover, enhancement of antioxidant capacity (TAC), and immune related gene expression of IL-1β were increased in the presence of SiO₂NPs compared with the groups of Pb exposure. Moreover, Pb residue level in fish muscles was noticeably decreased in the SiO₂NPs treated groups. Thus, this research opens up other possibilities in the field of using SiO₂NPs as a lead adsorbent for water bioremediation.

Copper Oxide Nanoparticle-Induced Acute Inflammatory Response and Injury in Murine Lung Is Ameliorated by Synthetic Secoisolariciresinol Diglucoside (LGM2605)

Metal-oxide nanoparticles (MO-NPs), such as the highly bioreactive copper-based nanoparticles (CuO-NPs), are widely used in manufacturing of hundreds of commercial products. Epidemiological studies correlated levels of nanoparticles in ambient air with a significant increase in lung disease. CuO-NPs, specifically, were among the most potent in a set of metal-oxides and carbons studied in parallel regarding DNA damage and cytotoxicity. Despite advances in nanotoxicology research and the characterization of their toxicity, the exact mechanism(s) of toxicity are yet to be defined. We identified chlorination toxicity as a damaging consequence of inflammation and myeloperoxidase (MPO) activation, resulting in macromolecular damage and cell damage/death. We hypothesized that the inhalation of CuO-NPs elicits an inflammatory response resulting in chlorination damage in cells and lung tissues. We further tested the protective action of LGM2605, a synthetic small molecule with known scavenging properties for reactive oxygen species (ROS), but most importantly, for active chlorine species (ACS) and an inhibitor of MPO. CuO-NPs (15 µg/bolus) were instilled intranasally in mice and the kinetics of the inflammatory response in lungs was evaluated 1, 3, and 7 days later. Evaluation of the protective action of LGM2605 was performed at 24 h post-challenge, which was selected as the peak acute inflammatory response to CuO-NP. LGM2605 was given daily via gavage to mice starting 2 days prior to the time of the insult (100 mg/kg). CuO-NPs induced a significant inflammatory influx, inflammasome-relevant cytokine release, and chlorination damage in mouse lungs, which was mitigated by the action of LGM2605. Preventive action of LGM2605 ameliorated the adverse effects of CuO-NP in lung.

The role of ascorbic acid combined exposure on Imidacloprid-induced oxidative stress and genotoxicity in Nile tilapia

Imidacloprid (Imid), a systemic neonicotinoid insecticide, is broadly used worldwide. It is reported to contaminate aquatic systems. This study was proposed to evaluate oxidative stress and genotoxicity of Imid on Nile tilapia (Oreochromis niloticus) and the protective effect of ascorbic acid (Asc). O. niloticus juveniles (30.4 ± 9.3 g, 11.9 ± 1.3 cm) were divided into six groups (n = 10/replicate). For 21 days, two groups were exposed to sub-lethal concentrations of Imid (8.75 ppm, 1/20 of 72 h-LC50 and 17.5 ppm, 1/10 of 72 h-LC50); other two groups were exposed to Asc (50 ppm) in combination with Imid (8.75 and 17.5 ppm); one group was exposed to Asc (50 ppm) in addition to a group of unexposed fish which served as controls. Oxidative stress was assessed in the liver where the level of enzymatic activities including superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) in addition to mRNA transcripts and, Lipid peroxidation (LPO) were evaluated. Moreover, mitotic index (MI) and comet assay were performed, in addition, the erythrocytic micronucleus (MN), and nuclear abnormalities (NA) were observed to assess genotoxicity in fish. Imid exposure induced significant (p ˂ 0.05) changes in the antioxidant profile of the juveniles' liver by increasing the activities and gene expression of SOD, CAT and GPX as well as elevating the levels of LPO. DNA strand breaks in gill cells, erythrocytes and hepatocytes along with erythrocytic MN and NA were also significantly elevated in Imid-exposed groups. MI showed a significant (p ˂ 0.05) decrease associated with Imid exposure. Asc administration induced a significant amelioration towards the Imid toxicity (8.75 and 17.5 ppm). A significant protective potency against the genotoxic effects of Imid was evidenced in Asc co-treated groups. Collectively, results highlight the importance of Asc as a protective agent against Imid-induced oxidative stress and genotoxicity in O. niloticus juveniles.

Effect of Dietary Sugarcane Bagasse Supplementation on Growth Performance, Immune Response, and Immune and Antioxidant-Related Gene Expressions of Nile Tilapia (Oreochromis niloticus) Cultured under Biofloc System

Simple Summary

Supplementation of agriculture by-product as functional feed additives in combination with biofloc technology (a sustainable and environmentally friendly technology) has recently gained much attention in aquaculture. In the present study, sugarcane bagasse powder can possibly be applied as a feed additive to improve growth performance, immune response, and immune and antioxidant-related gene expression.

Abstract

We investigated, herein, the effects of dietary inclusion of sugarcane bagasse powder (SB) on Nile tilapia development, mucosal and serum immunities, and relative immune and antioxidant genes. Fish (15.12 ± 0.04 g) were provided a basal diet (SB0) or basal diet incorporated with SB at 10 (SB10), 20 (SB20), 40 (SB40), or 80 (SB80) g kg⁻¹ for 8 weeks. Our results demonstrated that the dietary incorporation of sugarcane bagasse powder (SB) at 20 and 40 g kg⁻¹ significantly ameliorated FW, WG, and SGR as opposed to fish fed basal, SB10, and SB80 diets. However, no significant changes in FCR and survivability were observed between the SB supplemented diets and the control (basal diet). The mucosal immunity exhibited significantly higher SMLA and SMPA activities (p < 0.005) in fish treated with SB diets after eight weeks. The highest SMLA and SMPA levels were recorded in fish fed SB80 followed by SB20, SB40, and SB10, respectively. For serum immunity, fish fed SB incorporated diets significantly ameliorated SL and RB levels (p < 0.05) compared with the control. However, SP was not affected by the inclusion of SB in any diet throughout the experiment. The expression of IL1, IL8, LBP, GSTa, GPX, and GSR genes in the fish liver was significantly increased in fish fed the SB20 and SB10 diets relative to the basal diet fed fish (p < 0.05); whereas only the IL8, LBP, and GPX genes in the intestines were substantially augmented via the SB20 and SB80 diets (p < 0.05). IL1 and GSR were not influenced by the SB incorporated diets (p > 0.05). In summary, sugarcane bagasse powder (SB) may be applied as a feed additive to improve growth performance, immune response, and immune and antioxidant-related gene expression in Nile tilapia.

Dietary supplementation with melatonin: influence on growth performance, oxidative stress status, and amelioration of silver nanoparticles-induced toxicity in Nile tilapia (Oreochromis niloticus)

Excessive use of silver nanoparticles (AgNPs) due to antibacterial properties can raise concerns about their release into environment and potential toxicity in aquatic organisms. Melatonin has several physiological functions especially antioxidant potential against oxidative stress. The current study was conducted to investigate the potential effects of two doses of dietary melatonin on growth performance, plasma biochemistry, and liver enzyme activity in Nile tilapia (Oreochromis niloticus) juveniles. We also investigated the potential ameliorative effect of melatonin in AgNPs-induced biochemical alterations in tilapia fish. The results showed that melatonin-supplemented diets had no significant effect on growth performance of fish (P>0.05). The liver GPx activity increased in fish fed melatonin-supplemented diets (P<0.05), but the SOD activity showed no significant difference in comparison with the control (P>0.05). The administration of melatonin-supplemented diets reduced the activity of liver MDA compared to the control (P<0.05). Feeding fish with high melatonin-supplemented diet (200 mg kg^-1 of diet) decreased the plasma glucose, total protein, and AST levels (P<0.05). The liver GPx and SOD activities were higher in high melatonin-treated fish exposed to AgNPs than the control group (P<0.05). Dietary melatonin decreased the liver MDA activity in AgNPs-exposed fish. The plasma glucose, AST, and ALT levels in melatonin-treated fish exposed to AgNPs decreased compared to the untreated exposed fish (P<0.05). Melatonin-treated fish exposed to 0.05 and 0.5 mg L^-1 of AgNPs had lower plasma LDH level than the control group (P<0.05). The results showed that consumption of melatonin-supplemented diets could modulate some of the biochemical indices of plasma and liver in Nile tilapia. The findings also indicated the ameliorative effect of dietary melatonin on AgNPs-induced toxicity in Nile tilapia.

Impact of mycogenic zinc nanoparticles on performance, behavior, immune response, and microbial load in Oreochromis niloticus

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Biological ZnONPs have considerable bactericidal against pathogenic fish bacteria.

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Biological ZnONPs reduced the bacterial load in water and fish tissues.

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Biological ZnONPs enhanced FCR feeding and swimming behaviors.

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Biological ZnONPs stimulated fish health and production.

This work aims to evaluate the antibacterial activity of biological zinc nanoparticles (BIO-ZnONPs) against pathogenic fish bacteria and assess the effect of BIO-ZnONPs on the performance, behavior, and immune response in Nile tilapia (Oreochromis niloticus) as compared to chemical zinc nanoparticles (CH- ZnONPs). Aspergillus niger TS16 fabricated the BIO-ZnONPs were spherical shape with the average size of 45 nm and net charge of −27.23 mV. Generally, the results indicate that BIO-ZnONPs were more effective than CH- ZnONPs in enhancing the performance properties of Nile tilapia. Five experimental groups of Nile tilapia (initial body weight of 20.2 g) were treated with two concentrations of 0.5 and 1 mg L⁻¹ from biological and chemical ZnONPs, while the fifth group was served as a control. After ten weeks of treated water with ZnONPs, the performance, feed efficiency parameters, feeding, and swimming behaviors significantly improved in BIO-ZnONPs treated groups (P < 0.05). The liver function, LYZ activity, and NBT values were significantly enhanced in the 0.5 mg L⁻¹ BIO-ZnONPS group compared to CH- ZnONPs group and control (P < 0.05). Furthermore, the lowest cortisol and the highest testosterone and growth hormone levels were recorded in 1 mg L⁻¹ BIO-ZnONPs group. Regarding the antibacterial effects, BIO-ZnONPs displayed the lower total bacterial loads in water and fish tissues (intestine, gills, skin, and muscle) and the maximum antibacterial properties against pathogenic bacteria (Listeria monocytogenes, Bacillus cereus, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Aeromonas hydrophila). Our study exemplifies novel findings of BIO-ZnONPs in the promotion of fish health and production and its antibacterial properties in Nile tilapia.

Study on the impacts of chemical and green synthesized (Leucas aspera and oxy-cyclodextrin complex) dietary zinc oxide nanoparticles in Nile tilapia (Oreochromis niloticus)

The present study was designed to evaluate the health effects of dietary nanozinc prepared by two methods: conventional chemical method and green method. The parameters evaluated were the extent of bioaccumulation, antioxidant status, histological, immunological changes and DNA damage in Nile tilapia fed nanozinc feed. Zinc oxide nanoparticles were first prepared by green and chemical methods. Before feed preparation, the in vitro antioxidant activity and antibacterial activity of both types of nanoparticle solutions were tested and the results revealed enhanced activities in green synthesized ZnO NP solution. After the acclimatization period, 420 Nile tilapias were distributed randomly into 21 glass tanks with 20 fish per tank in triplicates. Fish were fed control diet without any ZnO NP and (i) GT1-green synthesized ZnO NP diet at 100 mg/kg, (ii) CT1-chemically synthesized ZnO NP diet at 100 mg/kg, (iii) GT2-green synthesized ZnO NP diet at 200 mg/kg, (iv) CT2-chemically synthesized ZnO NP diet at 200 mg/kg, (v) GT3-green synthesized ZnO NP diet at 400 mg/kg and (vi) CT3-chemically synthesized ZnO NP diet at 400 mg/kg for 60 days. After 60 days, gill and liver samples were collected for analysing oxidative stress, histopathological alterations and bioaccumulation of zinc, whereas serum samples were collected for evaluating immune response. The results revealed that the GT3 diet significantly (P < 0.05) enhanced the level of antioxidant enzymes (CAT, SOD, GPx, GR and GSH) than dietary nanozinc prepared by the chemical method. Similarly, the innate immunological parameters were significantly (P < 0.05) augmented in fish fed GT3 diet. Comparative histological study of liver and gill tissues revealed normal architecture in the tissues of fish fed green synthesized NP-enriched feed, whereas the tissues of fish fed chemically synthesized NP feed exhibited histological alterations. Bioaccumulation of zinc was more in the liver followed by the muscle and least in the gills and DNA damage was more evident in fish fed chemically synthesized ZnO NP-enriched feed. In conclusion, the results suggest that the inclusion of 400 mg/kg GT3 diet in fish diet enhanced the level of antioxidant enzymes, boosted immune response and did not cause histological damage to organs, and therefore, GT3 nanofeed can be recommended for fish health improvement.

Ameliorative effect of vitamins (E and C) on biochemical alterations induced by sublethal concentrations of zinc oxide bulk and nanoparticles in Oreochromis niloticus

The comparison between bulk and nano ZnO particles were antecedently studied but describing the dose-dependent toxicity and the ameliorative effect of vitamins (E and C) in Oreochromis niloticus, have not been previously documented. Therefore, the present study was designed to investigate the ameliorative effect of vitamins (E and C) against oxidative stress and biochemical alterations induced by sublethal concentrations of zinc oxide bulk particles (ZnOBPs) and zinc oxide nanoparticles (ZnONPs). Toxicity tests were carried out on O. niloticus and showed that 96 h LC₅₀ values of ZnOBPs and ZnONPs were 84 mg/l and 5.6 mg/l respectively. Exposure of the studied fish to these sublethel concentrations for 7, 14, 21 & 28 days showed a significant increase (p < 0.05) in serum glucose, AST, ALT, creatinine, urea and uric acid compared to control groups while, fish groups exposed to ZnOBPs or ZnONPs and supplemented with vitamins E and C, their serum enzyme concentrations were decreased compared to the groups without supplementation after 7, 14, 21 and 28 day. On the other hand, antioxidant defense enzymes (SOD, CAT and GST) activity in O.niloticus fish were increased significantly (p < 0.05) when exposed to sublethal concentrations of ZnOBPs or ZnONPs compared to the control value. However, fish groups supplemented with vitamins (E and C) have a decrease in SOD, CAT and GST enzymes activity when compared to unsupplemented groups and the values returned to similar levels established in the control at low concentrations but still higher than control at the high concentrations.

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

This study was conducted to compare the effects of commercially available (C) and green synthesized (GS) Zinc oxide nanoparticles (ZnO-NPs) on immunological responses of common carp (Cyprinus carpio) skin mucus. GS ZnO-NPs were generated using Thymus pubescent and characterized by UV–vis diffuse reflectance spectroscopy (DRS), Fourier-transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), scanning electron microscope (SEM), and energy-dispersive X-ray spectroscopy (EDX). Fish (n = 150) were randomly allocated into five groups in triplicate and received a waterborne concentration of 0% (control), 25%, and 50% of LC50 96 h of commercially available (C1 and C2) and green synthesized ZnO-NPs (GS1 and GS2) for 21 days. Results from XRD displayed ZnO-NPs with 58 nm in size and UV-vis DRS, EDX, and FT-IR analysis showed that some functional groups from plant extract bonded to the surface of NPs. The SEM images showed that ZnO-NPs have conical morphology. Acute toxicity study showed a higher dose of LC50_96h for green synthesized ZnO-NPs (78.9 mg.L⁻¹) compared to the commercial source (59.95 mg.L⁻¹). The highest activity of lysozyme and alternative complement activity (ACH50) were found in control and GS1 groups. A significant decrease in alkaline phosphatase activity (ALP) was found in C1 and C2 groups compared to other treatments. Protease activity (P) was significantly decreased in the C2 group compared to the control and GS groups. Total immunoglobulin (total Ig) content was the highest in the control. In addition, total Ig in the GS1 group was higher than GS2. The exposure to ZnO-NPs lowered total protein content in all experimental groups when compared to control. Present findings revealed lower induced immunosuppressive effects by green synthesized ZnO-NPs on key parameters of fish skin mucus.

Efficacy of nano zinc oxide dietary supplements on growth performance, immunomodulation and disease resistance of African catfish Clarias gariepinus

Zinc (Zn) is an important trace element in fish diets that is required for growth, immunity and antioxidant defense mechanisms. The current study assessed the effects of both organic and nanoparticle zinc oxide (ZnO and ZnO-NPs, respectively) on growth performance, immune response and the antimicrobial effect against Pseudomonas aeruginosa in African catfish Clarias gariepinus. Fish were fed either a control diet or diets supplemented with organic ZnO at concentrations of 20 and 30 mg kg-1 or ZnO-NPs at concentrations of 20 and 30 mg kg-1. After 60 d, a subset of the fish was injected intraperitoneally with 3 × 107 CFU ml-1 of P. aeruginosa. Results showed that body weight gain, feed conversion ratio and specific growth rates were significantly increased in ZnO-NPs20 compared to all other groups. The dietary supplementation with 20 mg kg-1 of ZnO-NPs improved the antioxidant status of fish. Moreover, IgM, lysozyme and nitric oxide showed a significant increase in the fish which received the ZnO-NPs20-supplemented diet. A significant upregulation of growth and stress-related genes was seen in the ZnO-NPs20-supplemented group compared to other groups. However, there was no significant difference in the expression of immune-related genes among ZnO-NPs20, ZnO-NPs30 and ZnO30 groups. These findings highlight the potential use of nano-ZnO for improving growth performance, antioxidant status, immunological status and antibacterial activity against P. aeruginosa in African catfish.

Trace elements exposure influences proximate body composition and antioxidant enzyme activities of the species tilapia and catfish in Burullus Lake-Egypt: human risk assessment for the consumers

The trace elements concentration in the fish estimates the contamination degree in the aquatic environment. These toxic trace elements are transported into the human through the consumption of polluted fish. This study estimated the effect of Cd, Hg, Pb, As, and Al on tilapia species and catfish Clarias gariepinus (six for each species of fish) inhabiting Burullus Lake-Egypt 30° 33'-31° 08' E and 30° 22'-31° 35' N. The highest Pb concentrations recorded in the muscle of C. gariepinus 2.29 ± 0.29 μg/g while S. galilaeus was estimated the lowest Hg concentration of 0.54 ± 0.02 μg/g which indicated the presence of contaminants exceeded the limits permitted by FAO/WHO and EC. The maximum mean carbohydrate, lipid, and protein recorded in O. niloticus 18.66, 16.33, and 58.16 mg/g, respectively; moisture in O. aureus 67.33%; and ash 16.41% in O. niloticus. The lowest amount of carbohydrate was recorded in the T. zillii 14.1 mg/g, lipid, and ash in C. gariepinus 11.65 mg/g and 3.375%, respectively. Protein and moisture in the S. galilaeus were 53.75 mg/g and 60.75%, respectively. The results recorded a marked insignificant (P > 0.05) decrease in CAT, GR, and GPx activity in O. niloticus. GSH and SOD activity was an insignificant (P > 0.05) decrease in C. gariepinus. The results concluded that the trace elements concentrations exceed the maximum permissible limits recommended in fish samples set by Egypt, FAO, WHO, and EC. The estimated weekly intake of all elements through consumption of studied fish species inhabiting Burullus Lake by a child (15 kg) in Egypt is well above the PTWI recommended by FAO/WHO, whereas it is well below the PTWI for human consumption by young people (40 kg) and adult person (70 kg), at least in respect of residual levels of studied elements excluding Cd and Hg. Thus, for consumer protection, these fish species are unsafe and have hazardous effects for children, and about youth and adult consumption, caution must be taken to consider individuals eating significant amounts of fish.

Antioxidative and immunoprotective potential of Chlorella vulgaris dietary supplementation against chlorpyrifos-induced toxicity in Nile tilapia

This study highlighted the effects of chronic chlorpyrifos (CPF) exposure on Nile tilapia (Oreochromis niloticus) and the benefits of using dietary Chlorella vulgaris (Ch) to ameliorate CPF-induced toxicity. Genes encoding antioxidant enzymes and stress-responsive proteins in the liver as well as cytokine expression in the spleen and head kidney were evaluated in O. niloticus fed with a basal diet or diets containing 1, 2, and 3% of supplementary Ch against 15 mg/L CPF at 4 and 8 weeks. CPF-exposed groups displayed a notable induction in the hepatic expression of heat shock protein 70/hsp70, glutathione peroxidase/GPx, and glutathione synthase/GSS, while glutathione reductase/GSR was markedly decreased. The mRNA levels of interleukin 1β/IL-1β, TNF-α, transforming growth factor β1/TGFβ1, and interleukin 8/ IL-8 in the spleen and head kidney increased significantly after CPF exposure. Interestingly, Ch supplementation, particularly at levels 2 and 3%, was able to modulate the stress and immune-related genes of Nile tilapia sub-chronically exposed to CPF. These outcomes provide valuable insights regarding the toxic impact of chronic exposure to CPF in fish at the molecular level and a better understanding of the Ch dietary vital roles. Besides, our findings encourage adequate monitoring of pesticide levels owing to its impacts on fish health and human as a final consumer.

Nitric oxide synthase-mediated sub-chronic injury and recovery in the small intestine of mice after oral administration with halloysite nanotubes

Natural halloysite nanotubes (HNTs) with a hollow lumen have been widely applied in many fields, such as water purification, drug carriers, cosmetics, antibacterial, and scaffolds for tissue engineering. However, their in vivo toxicity is still largely unclear. The aim of this study is to evaluate sub-chronic oral toxicity of HNTs in the small intestine of mice. The results demonstrated that oral HNTs at low dose (5 mg/kg) for 30 days promoted mouse growth with no obvious adverse effect on the small intestine. The promotive effect on mouse growth disappeared after cessation of oral administration of HNTs. Oral HNTs at high dose (50 mg/kg) for 30 days induced aluminum (Al) and silicon (Si) accumulation and oxidative stress in the small intestine, which caused significant increases in the levels of cyclooxygenase-2 (COX-2) and nitric oxide synthase (iNOS) and inflammatory response and iNOS-mediated damages in the organ. Oral HNTs-induced changes in the small intestine at high dose were not observed after a 30-day recovery period. These findings provided the first evidence that oral HNTs-induced sub-chronic toxicity in the small intestine was reversible. The results suggest that HNTs at low concentration in environments have no adverse effect on mice, while there are health risks to mice under severe contamination by HNTs.

Assessing the effectiveness of CoQ10 dietary supplementation on growth performance, digestive enzymes, blood health, immune response, and oxidative-related genes expression of Nile tilapia (Oreochromis niloticus)

The present study was conducted to investigate the effects of CoQ10 dietary supplementation on growth performance, feed utilization, blood profile, immune response, and oxidative status of Nile tilapia (12.4 ± 0.11 g, initial body weight). Five experimental diets were formulated containing CoQ10 at levels of 0, 10, 20, 30, 40 mg kg^-1 diet (D1, D2, D3, D4, and D5, respectively). The results of a 56-days feeding trial showed that, significantly higher weight gain % (WG %), specific growth rate (SGR), feed intake (FI), and feed efficiency ratio (FER) were recorded in fish groups fed diets supplemented with different levels of CoQ10 than fish fed the control diet, while survival rate (SR%), condition factor (CF), hepatosomatic index (HSI) and viscerasomatic index (VSI) showed no obvious differences (P > 0.05) among all experimental groups. The highest activities of digestive enzymes (protease, amylase, and lipase) were recorded in D3, D4, and D5 groups. Moreover, blood status of all experimental fish was within normal rates and significant alterations were only in the case of glucose, cortisol, total cholesterol (T-Chol), triglycerides, and total protein (TP), where fish fed on D3, D4 and D5 diets exhibited lower values of glucose, cortisol, T-Chol, and triglycerides and higher values of TP. Furthermore, the lowest values of immune response [lysozyme, bactericidal, respiratory burst (NBT), and alternative complement pathway activities (ACP)], antioxidant capacity and oxidative related genes expressions [superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GP_X)] resulted from feeding on the basal diet (D1) compared to CoQ10 diets, especially with its high levels {≥20 mg kg^-1 diet (D3, D4, and D5)} in most cases. In conclusion, our results suggest that the use of ≥20 mg CoQ10 kg^-1 diet improves the growth and health being of Nile tilapia.

Do predictive environmentally relevant concentrations of ZnO nanoparticles induce antipredator behavioral response deficit in Swiss mice?

The toxicity of zinc oxide nanoparticles (ZnO NPs) has been addressed in several studies; however, their effect on the mammalian group, even at environmentally relevant concentrations, remains poorly understood. The aims of the present study are to expose female Swiss mice to ZnO NP concentrations commonly faced by mammals who enter aquatic systems to perform different ecological functions and to assess the possible effects of such particles on their behavior. The test animals were placed in water added with ZnO NPs for 3 min, 2 times/day, for 21 days. Two experimental groups were set, NP1x, composed of animals subjected to ZnO NP concentration of 760 μg/L; and NP50x (control), which encompassed animals subjected to 38,000 μg/L. Based on field test results (OF), the contact with NPs did not induce locomotor deficits or anxiogenic and anxiolytic effect on the animal models. However, models exposed to NPs were not able to recognize the predatory threat posed by the presence of Pantherophis guttatus and Arapaima gigas; on the other hand, animals in the control group, who were not exposed to ZnO NPs, did not present antipredator behavioral response deficit. Furthermore, mice exposed to NPs were unable to distinguish real predators from plastic copies, and it suggests antipredator behavioral response deficit. High Zn concentrations in blood, liver, brain and skin samples are associated with deficit caused by the exposure to ZnO NPs. To the best of our knowledge, the current study is in the first to evidence that ZnO NPs induce changes in antipredator behavioral responses, even under ephemeral conditions and at low concentrations. However, the exposure to ZnO NPs can be a risk to the health of the assessed individuals and to the dynamics of their populations if the present antipredator behavioral response test results are extrapolated to the ecological context.

Comparison between the Effects of Adding Vitamins, Trace Elements, and Nanoparticles to SHOTOR Extender on the Cryopreservation of Dromedary Camel Epididymal Spermatozoa

Simple Summary

This is a comprehensive study to compare between the effects of different supplements (vitamins C and E, trace elements Na₂SeO₃ and ZnSO₄, and nanoparticles of zinc oxide and selenium) to the semen extender of camel epididymal spermatozoa during cooling and freezing/thawing cryopreservation. Supplementation of the semen SHOTOR extender with zinc oxide and selenium nanoparticles lead to improved progressive motility, vitality, and anti-oxidative defense, and reduced the ultrastructural abnormalities in camel epididymal spermatozoa.

Abstract

There are several obstacles in camel semen cryopreservation; such as increasing semen viscosity and the reduction in motile spermatozoa after ejaculation. Epididymal spermatozoa offer an efficient alternative to overcome these problems and are well-suited for artificial insemination in camels. In the current study, we compared the effects of supplementation with vitamin C, E, inorganic trace elements of selenium (Na₂SeO₃) and zinc (ZnSO₄), and zinc and selenium nanoparticles (ZnONPs and SeNPs, respectively) on the cryopreservation of dromedary camel epididymal spermatozoa. When the SHOTOR extender was supplemented with ZnONPs and SeNPs; the sperm showed increased progressive motility; vitality; and membrane integrity after cooling at 5 °C for 2 h; when compared to the control and vitamin-supplemented groups. Moreover, the ZnONPs and SeNPs supplementation improved the progressive motility, vitality, sperm membrane integrity, ultrastructural morphology, and decreased apoptosis when frozen and thawed. SeNPs significantly increased reduced glutathione (GSH), superoxide dismutase (SOD), and decreased lipid peroxide malondialdehyde (MDA) levels. The advantageous effects of the trace elements were potentiated by reduction into a nano-sized particle, which could increase bioavailability and reduce the undesired liberation of toxic concentrations. We recommend the inclusion of SeNPs or ZnONPs to SHOTOR extenders to improve the cryotolerance of camel epididymal spermatozoa.

Acute toxic effects caused by the co-exposure of nanoparticles of ZnO and Cu in rainbow trout

The toxic effects produced by the co-exposure to low- and non-toxic concentrations of zinc oxide (ZnONPs) and copper nanoparticles (CuNPs) was assessed in rainbow trout following the OECD Test Guideline 203. Four groups of trouts were exposed for 96 h to a range of concentrations (0.0425-0.34 mg/L) of CuNPs (50 nm) in combination with a fixed non-toxic concentration (1.25 mg/L) of ZnONPs (25 nm) determined from an independent concentration-response study. One additional group was exposed to the highest concentration of CuNPs alone. Behaviour and mortality were observed during the experiment. After 96 h exposure, accumulated levels of Cu and Zn in the fish were measured by ICP-MS and ICP-OES, respectively. The induction of oxidative stress in liver and gills was evaluated by the glutathione-S-transferase (GST) activity and the reduced glutathione (GSH) / oxidized glutathione (GSSG) ratio. The ethoxyresorufin-O-deethylase (EROD) activity was also assessed. The results showed that CuNPs at the highest tested concentration do not cause acute toxicity, whereas exposure to all mixtures caused mortality, which was inversely proportional to the concentration of CuNPs (from 28% to 86% survival). Accumulated levels of Cu and Zn in the fish increased with the increasing concentrations of CuNPs, suggesting that the presence of CuNPs favours the entry of Zn. In general, the GST activity increased significantly in the gills of co-exposed groups, whereas the GSH/GSSG ratio was altered in the liver. The EROD activity was not modified. In conclusion, the co-exposure to these NPs potentiates their toxicity, observing an alteration of the GST activity and GSH/GSSG ratio in gill and liver, which was more pronounced at the lowest concentration of CuNPs. The lower toxic effect observed with the highest concentrations of CuNPs coincides with a greater internalization of Zn.

Amelioration of titanium dioxide nanoparticle reprotoxicity by the antioxidants morin and rutin

The present study aimed to examine the ameliorative effects of morin and rutin on the reproductive toxicity induced by titanium dioxide nanoparticles (TiO₂NPs) in male rats. A total of seventy adult male Sprague-Dawley rats were randomly divided into seven groups, each comprising ten rats. Nanoreprotoxicity was induced by treating rats with TiO₂NPs at a dosage of 300 mg/kg body weight for 30 days. Morin (30 mg/kg body weight) and rutin (100 mg/kg body weight) were co-administered with or without TiO₂NPs to rats either individually or combined. Only distilled water was administered to the control group. The results showed that TiO₂NPs enhanced oxidative stress, indicated by reduced levels of antioxidants such as superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH) in testicular tissues, and increased levels of the lipid peroxidation marker malondialdehyde (MDA). TiO₂NPs significantly reduced the levels of sex hormones (testosterone, FSH, and LH), reduced sperm motility, viability, and sperm cell count, and increased sperm abnormalities, in addition to damaging the testicular histological architecture. TiO₂NPs resulted in the downregulation of 17β-HSD and the upregulation of proapoptotic gene (Bax) transcripts in the testicular tissues. Conversely, morin and/or rutin had a protective effect on testicular tissue. They effectively counteracted TiO₂NP-induced oxidative damage and morphological injury in the testis by conserving the endogenous antioxidant mechanisms and scavenging free radicals. Thus, we suggest that morin and rutin could be used to alleviate the toxicity and oxidative damage associated with TiO₂NP intake.

Endosulfan toxicity in Nile tilapia (Oreochromis niloticus) and the use of lycopene as an ameliorative agent

OBJECTIVES

Endosulfan is a broad-spectrum organochlorine insecticide that has been commercially in use for decades to control insect pests and has been found to pollute the aquatic environment. The current study was carried out to investigate the toxic effects of endosulfan, an organochlorine pesticide, on Nile tilapia (Oreochromis niloticus), a freshwater fish, and the alleviating effects of lycopene on the induced toxicity.

METHODS

Four treatment groups of fish were investigated (3 replicates of 15 fish for each group): (1) a control group, (2) a group exposed to endosulfan, (3) a group that was fed on a basal diet supplemented with lycopene, and (4) a group that was fed on a basal diet supplemented with lycopene and exposed to endosulfan. The experiment was carried out over a 4-week period.

RESULTS

Endosulfan negatively affected liver function, including liver enzymes and plasma proteins. Endosulfan affected blood parameters of fish and reduced the counts of red blood cells (RBCs) and white blood cells (WBCs), as well as affected immunological parameters. Endosulfan caused oxidative stress, as it decreased the values of antioxidants catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPX), and glutathione (GSH), and increased the level of lipid peroxide malondialdehyde (MDA). Additionally, endosulfan increased cytochrome P450 (CYP450) levels, while it decreased glutathione S-transferase (GST) mRNA transcript levels and distorted the normal histological structure of the liver, gills, and spleen of affected fish. Conversely, lycopene partially restored the aforementioned parameters when administered concomitantly with endosulfan.

CONCLUSION

The results showed the beneficial effects of supplementing fish diets with lycopene as a natural antioxidant for ameliorating the toxicity caused by endosulfan.

Analysis of ZnO nanoparticle-induced changes in Oreochromis niloticus behavior as toxicity endpoint

The toxicity of zinc oxide nanoparticles (ZnO NPs) has been investigated in different animal models. However, concentrations tested in most studies are often much higher than the ones potentially identified in the environment. Therefore, such toxicity limits the application of these studies to evaluate ecotoxicological risks posed by these nanopollutants. Thus, the aim of the current study is to evaluate the impacts of ZnO NPs (at environmentally relevant concentrations - 760 μg/L and 76,000 μg/L, for 72 h) on the behavioral responses of Oreochromis niloticus (Nile tilapia) exposed to it. Results did not evidence harmful effects of NPs on animals' locomotor abilities (evaluated through open-field and light-dark transition tests), or anxiety-predictive behavior. On the other hand, Zn bioaccumulation in the body tissues of the analyzed tilapias was correlated to changes in eating behavior (motivated by ration pellets), as well as to deficits in antipredatory defensive behavior (under individual and collective conditions). Tilapia exposed to ZnO NPs recorded lower avoidance, flight and territorialist behavior rates when they were individually confronted with potential predators (Salminus brasiliensis). However, collectively exposed animals were unable to recognize their predators, as well as to differentiate them from artificial baits ("false predators"). The present study is the first to report biological impacts resulting from the short exposure of fish-group representatives to ZnO NPs. Thus, we believe that it may be relevant to improve the knowledge about ecotoxicological risks posed by these pollutants.

Hexavalent chromium-induced toxic effects on the antioxidant levels, histopathological alterations and expression of Nrf2 and MT2 genes in the branchial tissue of Ctenopharyngodon idellus

Ability of hexavalent chromium to accumulate and induce oxidative stress has been studied in the gills of Ctenopharyngodon idellus, with the resulting damage in the form of altered endogenous antioxidant enzyme activity and, histopathology in the tissue. The fish were exposed to 5.3 (C1) and 10.63 mg/L (C2) of hexavalent chromium and were scrutinised on 15th, 30^th and 45th day of toxicant exposure. Oxidative stress studied in terms of lipid peroxidation and glutathione levels and the antioxidant enzymes activity also exhibited alterations. The histopathological modifications in gills announced lesions in the form of hyperplasia, aneurysm, lamellar fusion, focal proliferation, epithelial degeneration and necrosis with loss of lamellae, bringing irreversible damage on 45th day with mean degree of tissue change value of 100.35 ± 10.69. Bioaccumulation of chromium, and increased anomalies in branchial tissue exhibited damage in concentration and time-dependent manner. The ultrastructural anomalies in the cellular morphology in the epithelial cells of filaments and lamellae, exhibited pleomorphic nuclei, swollen mitochondria, extensive vacuolation and loss of microridges in pavement cells. The tissue also displayed altered regulation of Nrf2 and Mt2 following Cr(VI) exposure with maximum downregulation on 45th day by 61 and 53%, respectively. PCA generated two principal components, PC1 (GSH, GST, CAT and SOD) and PC2 (DTC, MDA and Cr(VI) concentration). Thus, it can be concluded that accumulation of Cr(VI) induces alteration in the gene expression of Nrf2 and Mt2 leading to the development of oxidative stress, ensuing various pathological changes creating hindrance in fish survival.

The influence of surface waters on the bioavailability and toxicity of zinc oxide nanoparticles in freshwater mussels

The release of engineered nanoparticles in the aquatic environment could pose a threat to the biota. The purpose of the study was to examine the influence of surface water characteristics on zinc oxide nanoparticles (nZnO) and ZnS0₄ toxicity to the freshwater mussel Dreissena polymorpha. Mussels were exposed to an equivalent concentration of 25 μg/L Zn as either nZnO or ZnSO₄ for 96 h at 15 °C in 4 types of surface waters: green water (high conductivity and pH with low natural organic matter content), brown water (low conductivity and pH with high natural organic matter content), diluted municipal effluent (high conductivity and pH with high urban organic matter content) and aquarium water (treated green water with organic matter removed). After the exposure period, mussels were analyzed for air-time survival, total and labile Zn levels in tissues, lipid metabolism (phospholipase A2, triglycerides levels) and oxidative stress (glutathione S-transferase, arachidonate cyclooxygenase, lipid peroxidation). The data revealed that mussels exposed to ZnSO₄ in controlled aquarium water accumulated more total and labile Zn tissues, decreased oxidative stress and triglycerides and increased air time survival. While nZnO had few effects in aquarium water, oxidative stress was enhanced and total Zn in tissues were decreased in brown water and diluted municipal effluent and triglycerides were higher in nZn-exposed mussels in brown water. Air-time survival was decreased in mussels kept in green water and nZnO. It was also decreased in mussels exposed to ZnSO₄ in green water and diluted municipal effluent. In conclusion, the fate and toxic effects of Zn could be influenced by both the chemical form (nanoparticles or ionic Zn) and surface water properties in freshwater mussels.