Nano-copper Enhances Gene Regulation of Non-specific Immunity and Antioxidative Status of Fish Reared Under Multiple Stresses

Comparative study of influence of Cu, CuO nanoparticles and Cu2+ on rainbow trout (Oncorhynchus mykiss W.) spermatozoa

The same elements can yield disparate nanoproducts that may elicit different harmful effects in cells and organisms. This study aimed to compare the effects of copper (Cu NPs) and copper oxide (CuO NPs) nanoparticles and Cu2+ (from CuSO4) on the physico-biochemical variables of rainbow trout spermatozoa. The cell death assay, along with the activation of caspases 8 and 9, the level of reactive oxygen species (ROS), and the percentage of cells exhibiting a high mitochondrial membrane potential (MMP) were quantified over 24-hour incubation. Interestingly, during exposure, all copper products induced cell apoptosis. However, Cu NPs had a stronger effect than CuO NPs, while the impact of the Cu in ionic form was found to be between the other two compounds. The extrinsic and intrinsic apoptotic pathways were activated, as evidenced by the activation of caspases 8 and 9. Initially, caspase activation increased without a corresponding decrease in MMPs but prolonged exposure resulted in a significant decrease in MMP levels. In all treated cells, the ROS levels increased over time. Further studies are needed to confirm the lower CuO NPs' toxicity compared to Cu NPs because their effect on cells also depends on many other parameters such as size or shape.

Unraveling gene regulation mechanisms in fish: insights into multistress responses and mitigation through iron nanoparticles

The recent trend of global warming poses a significant threat to ecosystems worldwide. This global climate change has also impacted the pollution levels in aquatic ecosystems, subsequently affecting human health. To address these issues, an experiment was conducted to investigate the mitigating effects of iron nanoparticles (Fe-NPs) on arsenic and ammonia toxicity as well as high temperature stress (As+NH3+T). Fe-NPs were biologically synthesized using fish waste and incorporated into feed formulations at 10, 15, and 20 mg kg-1 diet. A total of 12 treatments were designed in triplicate following a completely randomized design involving 540 fish. Fe-NPs at 15 mg kg-1 diet notably reduced the cortisol levels in fish exposed to multiple stressors. The gene expressions of HSP 70, DNA damage-inducible protein (DDIP), and DNA damage were upregulated by stressors (As+NH3+T) and downregulated by Fe-NPs. Apoptotic genes (Cas 3a and 3b) and detoxifying genes (CYP 450), metallothionein (MT), and inducible nitric oxide synthase (iNOS) were downregulated by Fe-NPs at 15 mg kg-1 diet in fish subjected to As+NH3+T stress. Immune-related genes such as tumor necrosis factor (TNFα), immunoglobulin (Ig), and interleukin (IL) were upregulated by Fe-NPs, indicating enhanced immunity in fish under As+NH3+T stress. Conversely, Toll-like receptor (TLR) expression was notably downregulated by Fe-NPs at 15 mg kg-1 diet in fish under As+NH3+T stress. Immunological attributes such as nitro blue tetrazolium chloride, total protein, albumin, globulin, A:G ratio, and myeloperoxidase (MPO) were improved by dietary Fe-NPs at 15 mg kg-1 diet in fish, regardless of stressors. The antioxidant genes (CAT, SOD, and GPx) were also strengthened by Fe-NPs in fish. Genes associated with growth performance, such as growth hormone regulator (GHR1 and GHRβ), growth hormone (GH), and insulin-like growth factor (IGF 1X and IGF 2X), were upregulated, enhancing fish growth under stress, while SMT and MYST were downregulated by Fe-NPs in the diet. Various growth performance indicators were improved by dietary Fe-NPs at 15 mg kg-1 diet. Notably, Fe-NPs also enhanced arsenic detoxification and reduced the cumulative mortality after a bacterial infection. In conclusion, this study highlights that dietary Fe-NPs can effectively mitigate arsenic and ammonia toxicity as well as high temperature stress by modulating gene expression in fish.

Significance of dietary quinoa husk (Chenopodium quinoa) in gene regulation for stress mitigation in fish

The persistent challenges posed by pollution and climate change are significant factors disrupting ecosystems, particularly aquatic environments. Numerous contaminants found in aquatic systems, such as ammonia and metal toxicity, play a crucial role in adversely affecting aquaculture production. Against this backdrop, fish feed was developed using quinoa husk (the byproduct of quinoa) as a substitute for fish meal. Six isonitrogenous diets (30%) and isocaloric diets were formulated by replacing fish meal with quinoa husk at varying percentages: 0% quinoa (control), 15, 20, 25, 30 and 35%. An experiment was conducted to explore the potential of quinoa husk in replacing fish meal and assess its ability to mitigate ammonia and arsenic toxicity as well as high-temperature stress in Pangasianodon hypophthalmus. The formulated feed was also examined for gene regulation related to antioxidative status, immunity, stress proteins, growth regulation, and stress markers. The gene regulation of sod, cat, and gpx in the liver was notably upregulated under concurrent exposure to ammonia, arsenic, and high-temperature (NH3 + As + T) stress. However, quinoa husk at 25% downregulated sod, cat, and gpx expression compared to the control group. Furthermore, genes associated with stress proteins HSP70 and DNA damage-inducible protein (DDIP) were significantly upregulated in response to stressors (NH3 + As + T), but quinoa husk at 25% considerably downregulated HSP70 and DDIP to mitigate the impact of stressors. Growth-responsive genes such as myostatin (MYST) and somatostatin (SMT) were remarkably downregulated, whereas growth hormone receptor (GHR1 and GHRβ), insulin-like growth factors (IGF1X, IGF2X), and growth hormone gene were significantly upregulated with quinoa husk at 25%. The gene expression of apoptosis (Caspase 3a and Caspase 3b) and nitric oxide synthase (iNOS) were also noticeably downregulated with quinoa husk (25%) reared under stressful conditions. Immune-related gene expression, including immunoglobulin (Ig), toll-like receptor (TLR), tumor necrosis factor (TNFα), and interleukin (IL), strengthened fish immunity with quinoa husk feed. The results revealed that replacing 25% of fish meal with quinoa husk could improve the gene regulation of P. hypophthalmus involved in mitigating ammonia, arsenic, and high-temperature stress in fish.

Multifunctional role of dietary copper to regulate stress-responsive gene for mitigation of multiple stresses in Pangasianodon hypophthalmus

It is an urgent needs to address climate change and pollution in aquatic systems using suitable mitigation measures to avoid the aquatic animals' extinction. The vulnerability and extinction of the aquatic animals in the current scenario must be addressed to enhance safe fish food production. Taking into consideration of such issues in fisheries and aquaculture, an experiment was designed to mitigate high temperature (T) and low pH stress, as well as arsenic (As) pollution in fish using copper (Cu) containing diets. In the present investigation, the Cu-containing diets graded with 0, 4, 8, and 12 mg kg-1 were prepared and fed to Pangasianodon hypophthalmus reared under As, low pH, and high-temperature stress. The gene expression was highly affected in terms of the primary, secondary, and tertiary stress response, whereas supplementation of Cu-containing diet mitigates the stress response. Oxidative stress genes such as catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx) were significantly upregulated by stressors (As, As + T, and As + pH + T). Whereas, heat shock protein (HSP 70), inducible nitric oxide synthase (iNOS), metallothionine (MT), caspase 3a (Cas 3a), and cytochrome P450 (CYP 450) were highly upregulated by stressors, while dietary Cu at 8 mg kg-1 diet significantly downregulated these gene expressions. Indeed, the immunity-related genes viz. TNFα, Ig, TLR, and immune-related attributes viz. albumin, globulin, total protein, A:G ratio, blood glucose, NBT, and myeloperoxidase (MPO) were also improved with Cu-containing diets. Cu containing diets substantially improved neurotransmitter enzyme (AChE) and vitamin C (Vit C). DNA damage was also reduced with supplementation of Cu at 8 mg kg-1 diet. The growth index viz. final body weight gain (%), specific growth rate, protein efficiency ratio, food conversion ratio, relative feed intake, and daily growth index were noticeably enhanced by Cu diets (4 and 8 mg kg-1 diet). The growth-related genes expressions viz. growth hormone (GH), growth hormone regulator 1 (Ghr1), growth hormone regulator β (Ghrβ,) myostatin (MYST), and somatostatin (SMT) supported the growth enhancement with Cu at 8 mg kg-1 diet. The bioaccumulation of As was reduced with Cu-containing diets. The fish were infected with Aeromonas hydrophila at the end of the 105 days experimental trial. Cu at 8 mg kg-1 diet improved immunity, reduced the cumulative mortality, and enhanced the relative percentage survival of the fish. The results revealed that the innovative Cu diets could reduce the extinction of the fish against climate change and pollution era and produce the safest production that is safe to humans for consumption.

Manganese nanoparticles control the gene regulations against multiple stresses in Pangasianodon hypophthalmus

Ammonia and arsenic pollution, along with the impact of climate change, represent critical factors influencing both the quantity and quality of aquaculture production. Recent developments have underscored the significance of these issues, as they not only disrupt aquatic ecosystems but also have far reaching consequences for human health. To addressed above challenges, an experiment was conducted to delineate the potential of manganese nanoparticles (Mn-NPs) to mitigate arsenic and ammonia pollution as well as high temperature stress in Pangasianodon hypophthalmus. The fish were exposed to different combination of arsenic and ammonia pollution as well as high temperature stress, while simultaneously incorporating diets enriched with Mn-NPs. The inclusion of Mn-NPs at 3 mg kg-1 in the diet led to a noteworthy downregulation of cortisol and HSP 70 gene expression, indicating their potential in mitigating stress responses. Furthermore, immune related gene expressions were markedly altered in response to the stressors but demonstrated improvement with the Mn-NPs diet. Interestingly, the expression of inducible nitric oxide synthase (iNOS), caspase (CAS), metallothionine (MT) and cytochrome P450 (CYP450) genes expression were prominently upregulated, signifying a stress response. Whereas, Mn-NPs at 3 mg kg-1 diet was significantly downregulated theses gene expression and reduces the stress. In addition to stress-related genes, we evaluated the growth-related gene expressions such as growth hormone (GH), growth hormone regulator 1 (GHR1 and GHRβ), Insulin like growth factor (IGF1 and IGF2) were significantly upregulated whereas, myostatin and somatostatin were downregulated upon the supplementation of dietary Mn-NPs with or without stressors in fish. The gene expression of DNA damage inducible protein and DNA damage in response to head DNA % and tail DNA % was protected by Mn-NPs diets. Furthermore, Mn-NPs demonstrated a capacity to enhance the detoxification of arsenic in different fish tissues, resulting in reduced bioaccumulation of arsenic in muscle and other tissues. This finding highlights Mn-NPs as a potential solution for addressing bioaccumulation associated risks. Our study aimed to comprehensively examined the role of dietary Mn-NPs in mitigating the multiple stressors using gene regulation mechanisms, with enhancing the productive performance of P. hypophthalmus.