Recent reports from worldwide reveal that micro/nanoplastics (MNPs) are pervasive pollutants affecting all ecosystems and a wide range of organisms, including animals, plants, fish, humans, and microorganisms. MNPs have been detected in food items, mother milk, vegetables, and other consumable products, indicating their potential to impact organisms across all life stages. These particles can enter the body through inhalation, ingestion, and dermal contact. Due to their small size, micro/nanoplastics can be readily absorbed by animals and plants, leading to adverse effects on human health and ecological integrity. The present review addresses recent concerns related to MNPs pollution in aquatic animals and crops, with a particular focus on fish and rice. Exposure to MNPs has been reported to impair fish growth performance, immune responses, antioxidant status, digestive functions, reproduction, transgenerational effects, endocrine regulation, vitellogenin induction, neurotransmitter activity, and blood biochemical profiles. Similarly, MNPs adversely affect rice production by influencing various stages of the cropping system, including seed germination, vegetative growth, root and shoot development, tillering, and grain yield. Notably, both fish and rice are staple food sources for humans, highlighting the significance of this issue for food safety and public health. This review emphasizes the urgent need for comprehensive studies on the impacts of micro/nanoplastics on aquatic animals and major food crops. It integrates systematic knowledge on the effects of MNPs on fish growth patterns, immunity, endocrine disruption, reproduction, and key physiological indices, as well as on rice growth and productivity. The synthesized information will be highly valuable for policymakers, government agencies, pollution control authorities, and other stakeholders in policy formulation and decision-making processes.

BackgroundClimate change, pollution, and deteriorating water quality have emerged as major threats to aquaculture and fish reproduction. Anabas testudineus were exposed to multiple abiotic stressors such as arsenic, ammonia toxicity, low pH, and elevated temperature, which disrupt endocrine regulation, impair reproductive hormones, reduce sperm quality, and ultimately decrease reproductive efficiency. These stressors adversely affect the hypothalamic-pituitary-gonadal axis, resulting in hormonal imbalance and poor gamete quality of fish. The present investigation aims to protect the fish against endocrine disruption and improve reproductive hormones by using cobalt nanoparticles diets (Co-NPs).MethodsAn experiment was conducted for 115 days in Anabas testudineus of five hundred and four (504) with an average weight of 9.54 ± 0.25 g. The experiment was designed with twelve treatments in triplicate. The experiment was conducted in the triplicate. Cobalt nanoparticles (Co-NPs) were synthesized using green approach and formulated fish diet at 0.2, 0.4, 0.6 and 0.8 mg kg-1 diet. The arsenic (1/10th LC50, 2.05 mg L-1), ammonia (1/10th of LC50 2.3), low pH (6.5), and elevated temperature (34 °C) were maintained throughout the experiment for 115 days. The endocrine disruption, reproductive hormones and milt quality were evaluated.ResultsReproductive hormones in both male and female fish such as gonadotropin-releasing hormone (GnRH), progesterone, 11-keto-testosterone (11-KT), follicle-stimulating hormone (FSH), luteinizing hormone-releasing hormone (LH-RH), vitellogenin (Vt), and estradiol (in females) were significantly improved with Co-NP supplementation at 0.4 and 0.6 mg kg-¹ under both control and As+NH3+pH+T exposure conditions. Co-NPs supplementation also protects from endocrine disruption in the present study. Furthermore, milt/sperm characteristics were evaluated under multiple abiotic stressors and dietary Co-NP treatments. Milt count, milt motility, straight-line velocity (VSL), curvilinear velocity (VCL), progressive motility, average path velocity, linearity (%), and straightness (%) were substantially enhanced by dietary Co-NPs at 0.4 and 0.6 mg kg-¹, with or without stress exposure.ConclusionsDietary supplementation of Co-NPs at 0.4 and 0.6 mg kg-¹ demonstrated strong potential to improve reproductive efficiency in A. testudineus under combined abiotic stress conditions (As+NH3+pH+T).

BackgroundThe sustainability of aquaculture is increasingly threatened by major challenges such as aquatic pollution, excessive water abstraction, and climate change. Fish reared under such compromised environmental conditions often accumulate various contaminants, posing risks to consumer health. This study addresses these issues by formulating iron (Fe) based diets in Pangasianodon hypophthalmus reared under controlled conditions and simultaneously exposed to low levels of ammonia, arsenic, and high-temperature stress (NH3+As+T). However, the present investigation specifically focuses on the use of iron to mitigate the combined effects of ammonia, arsenic, and elevated temperature stress in P. hypophthalmus.MethodsAn experiment was conducted to evaluate the efficacy of dietary Fe at 40, 50, and 60 mg kg-¹ in mitigating the concurrent toxicity of ammonia, arsenic, and high temperature in P. hypophthalmus. A total of 360 fish were used in this study. Each treatment included 45 fish, with 15 fish stocked per replicate. Total RNA was isolated and quantified using the TRIzol method, followed by cDNA synthesis and quantitative PCR to assess differential gene regulation. Physiological parameters, protein and carbohydrate metabolic enzymes, cortisol levels, and immunological markers were analyzed. Additionally, arsenic bioaccumulation and DNA damage (single-cell gel electrophoresis) were evaluated.ResultsThe genes HSP70, CYP450, Caspase 3a and 3b, iNOS, MT, and Na+/K+-ATPase in liver tissue were markedly upregulated in fish exposed to the combined stressors (NH3+As+T). Notably, these genes were also significantly upregulated in the group supplemented with 50 mg kg-¹ Fe compared to control and stressed groups. Furthermore, immune-related genes such as TNF-α, IL, Ig, and TLR showed improvement with Fe supplementation. In contrast, growth-related genes including GH, GHR1, GHRβ, IGF1X, IGF2X, SMT, and MYST were significantly altered by exposure to the stressors.ConclusionsOverall, the findings demonstrate the potential of dietary iron as an effective strategy to enhance fish health and physiological resilience under multiple environmental stressors. The study provides mechanistic insights into how Fe supplementation modulates gene expression and cellular metabolic pathways to mitigate the toxic effects of ammonia, arsenic, and high temperature in Pangasianodon hypophthalmus.

The fishmeal is boon for aquaculture production in this recent pollution and climate change era. However, the demand of fishmeal is enhancing in many folds which needs to find alternative to fishmeal in cheap price. The present investigation addresses these issues with quinoa husk (QH). An experiment was performed to evaluate replacement of fishmeal by QH in different proportionate at 0, 15, 20, 25, 30 and 35%. The study was designed with 12 treatments as control, stressors group (concurrent exposed to ammonia, arsenic and high temperature stress, NH3+As+T), group fed with QH at 15, 20, 25, 30 and 35% without and with stressors (NH3+As+T) in Pangasianodon hypophthalmus for 105 days. The optimization of QH dose for growth performance such as food conversion ratio, growth rate, protein efficiency ratio and specific growth rate with respect to protein percentage and obtained 26%. The oxidative enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione-s-transferase (GST) and glutathione peroxidase (GPx) in gill, kidney and liver tissues were significantly lowered by replacement of fishmeal by QH at 25% in fish reared under arsenic and ammonia toxicity and high temperature stress (NH3+As+T). The neurotransmitter enzyme (AChE) in brain tissue was noticeably enhanced by QH at 25%. The aspartate amino transferase (AST) and alanine amino transferase (ALT) as well as malate dehydrogenase (MDH) and lactate dehydrogenase (LDH) in gill and liver were significantly reduced by QH at 25% in fish reread under multiple stresses (NH3+As+T). The nitro blue tetrazolium (NBT), blood glucose, albumin, globulin, total protein, A:G ratio, myeloperoxidase (MPO) and total immunoglobulin (Ig) were noticeably improved by supplementation of QH at 25–30% in fish reared under NH3+As+T. The amylase, protease and lipase were significant improved with replacement of fishmeal by QH at 25%. The histo-pathological alterations were marked in liver and gill tissues, whereas these tissues were protected by QH at 25% in fish reared under control and stress condition (NH3+As+T). The present study revealed that replacement of fishmeal at 25% by QH could be a better replacement for improvement in anti-oxidative status, acetylcholine esterase and growth performance in fish reread under NH3+As+T stress.

Contaminants are a major cause of seafood export rejections in foreign markets and have significantly impacted consumer health. This investigation addresses the issues of metal contamination and biochemical markers in Litopenaeus vannamei from East Midnapore, West Bengal, India. The analyzed metals included vanadium (V), chromium (Cr), manganese (Mn), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), molybdenum (Mo), silver (Ag), gallium (Ga), germanium (Ge), arsenic (As), selenium (Se), strontium (Sr), tin (Sn), cadmium (Cd), mercury (Hg), and lead (Pb), using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Samples were collected from the muscle and hepatopancreas of L. vannamei, as well as from soil sediments and water at 19 sampling sites. The trace element levels detected were within the safety limits recommended by national and international regulatory agencies. A risk assessment, based on the Total Hazard Quotient (THQ) and cancer risk factors, indicated that L. vannamei cultured in this region is safe for human consumption. Additionally, oxidative enzymes such as catalase, superoxide dismutase, and glutathione s-transferase were measured as biomarkers. Other biochemical markers, including lipid peroxidation and acetylcholinesterase activity, were also assessed. Enzymes such as alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase, and malate dehydrogenase were identified as key biochemical indicators of pollution in this study. In conclusion, the findings suggest that the consumption of L. vannamei from East Midnapore is safe according to FAO/WHO guidelines. The study also highlights the utility of biochemical markers as reliable indicators of pollution in open water systems.

The present study addresses the challenges of uncontrolled temperature and pollution in aquatic environments, with a focus on fish ability to tolerate high temperature. The investigation aimed to determine the role of iron nanoparticles (Fe-NPs) in enhancing the thermal tolerance of Pangasianodon hypophthalmus exposed to high-temperature stress, arsenic (As), and ammonia (NH3) toxicity. Fe-NPs were synthesized using green approaches, specifically from fish gill. The dietary Fe-NPs were formulated and supplemented at 10, 15, and 20 mg kg⁻1 of feed. Notably, Fe-NPs at 15 mg kg⁻1 diet significantly reduced the critical thermal minimum (CTmin) (14.44 ± 0.21 °C) and the lethal thermal minimum (LTmin) (13.46 ± 0.15 °C), compared to the control and other treatment groups. Conversely, when Fe-NPs at 15 mg kg⁻1 were supplemented with or without exposure to stressors (As + NH3+T), the critical thermal maximum (CTmax) increased to 47.59 ± 0.16 °C, and the lethal thermal maximum (LTmax) increased to 48.60 ± 0.37 °C, both significantly higher than the control and other groups. A strong correlation was observed between LTmin and CTmin (R2 = 0.90) and between CTmax and LTmax (R2 = 0.98). Furthermore, dietary Fe-NPs at 15 mg kg⁻1 significantly upregulated the expression of stress-related genes, including HSP70, iNOS, Caspase-3a, CYP450, MT, cat, sod, gpx, TNFα, IL, TLR, and Ig. The enhanced thermal tolerance (LTmin and LTmax) can be attributed to these gene regulations, suggesting the mechanistic involvement of Fe-NPs in improving thermal resilience. Overall, the findings demonstrate that dietary supplementation with Fe-NPs, particularly at 15 mg kg⁻1, improves thermal tolerance and stress response in P. hypophthalmus by enhancing gene expression and overall thermal efficiency under stressor conditions.

Intercropping offers greater scope to introduce new crops. Cultivation of crops with diverse root architecture and different durations enhances the productivity of scarce resources like land and water. This study aimed to determine the effect of intercrop competition and irrigation regimes on yield, competition, land usage, irrigation water use efficiency (IWUE), and fatty acids of chia. The field experiment was conducted in semi-arid India during 2020–2022 with full (I100) and deficit irrigation (I50) and six intercrops. Results demonstrated that chia + fenugreek intercropping in I50 improved the crops’ competitiveness, land equivalent ratio (LER) (1.77), land use efficiency (142.5%), and the IWUE of chia (23.2%). Notably, a chia + radish/spinach system in I50 reduced the seed yield (42.6–45.0%) of chia over I100 monocropping. A chia + fenugreek system in I50 resulted in a higher seed yield (196.2 kg ha−1) than chia monocropping in I100. Further, chia + fenugreek intercropping resulted in higher omega-3 content (56.68%) under I100. Therefore, a chia + fenugreek system under I100 may be suggested over monocropping for better yield and oil quality. However, during water scarcity situations, growers can adopt a chia + fenugreek system under I50 which can give a similar chia equivalent yield and a higher LER and IWUE compared to chia monocropping under I100.

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.

Aquaculture is the fastest-growing food industry, providing quality protein to the world. To produce the best-quality protein for human use, fish production requires improvements in both quality and quantity, as well as improved food security. Moreover, several abiotic and biotic factors prevalent in aquatic ecosystems, including chemical contaminants and diseases caused by microorganisms, have degraded the environment and led to worsened feed utilization by the fish. To overcome this problem, new technology is needed in the form of nanotechnology interventions for fishery management. Nanotechnology in aquaculture, including fisheries, is still in the early stages with respect to applications, but it has tremendous potential to improve production in the fisheries sector. In this connection, zinc is the most suitable micronutrient to be used in the form of nanoparticles for enhancement of production systems. Zinc is a key micronutrient and is obtained through both water and feed to fulfill aquatic animal requirements. Zn NPs can be used in feed supplements, medicine, vaccines, pond water purification, growth promoters, reproductive enhancers, and other applications. It also can have toxic effects at higher concentrations and can alter the growth promotion, reduce reproductive performance, and exhibit bioaccumulation in different fish tissues. It has been concluded, however, that nanotechnology can be adopted in the fisheries and aquaculture sector for enhancing production and minimizing the abiotic and biotic stress factors of aquatic systems.

In the present study, the bioaccumulation of chromium, manganese, cobalt, copper, zinc, selenium, arsenic, strontium, cadmium, tin, antimony and lead in tissues of thirty marine fish species collected from New Ferry Whorf, Sassoon dock and Versova fishing harbour in Mumbai, India, were analysed. The bioaccumulation patterns of these twelve elements were determined to assess pollution biomarkers based on cellular and oxidative stresses. Catalase, superoxide dismutase and glutathione-s-transferase, glycolytic enzymes viz. lactate dehydrogenase and malate dehydrogenase, protein metabolism enzymes viz. aspartate transferase and alanine transferase, and lipid peroxidation were significantly higher in muscle and gill tissues. The activities of the neurotransmitter enzyme acetylcholine esterase in muscle and brain tissues was inhibited due to pollution. This study suggested that biochemical attributes such as oxidative stress enzymes, cellular biomarkers, neurotransmitter enzymes and metal and metalloid contamination could be successfully employed, even at low concentrations, as reliable biomarkers for biomonitoring of contaminated marine ecosystems.

Climate change impact has disturbed the rainfall pattern worsening the problems of water availability in the aquatic ecosystem of India and other parts of the world. Arsenic pollution, mainly through excessive use of groundwater and other anthropogenic activities, is aggravating in many parts of the world, particularly in South Asia. We evaluated the efficacy of selenium nanoparticles (Se-NPs) and riboflavin (RF) to ameliorate the adverse impacts of elevated temperature and arsenic pollution on growth, anti-oxidative status and immuno-modulation in Pangasianodon hypophthalmus. Se-NPs were synthesized using fish gill employing green synthesis method. Four diets i.e., Se-NPs (0 mg kg−1) + RF (0 mg kg−1); Se-NPs (0.5 mg kg−1) + RF (5 mg kg−1); Se-NPs (0.5 mg kg−1) + RF (10 mg kg−1); and Se-NPs (0.5 mg kg−1) + RF (15 mg kg−1) were given in triplicate in a completely randomized block design. The fish were treated in arsenic (1/10th of LC50, 2.68 mg L−1) and high temperature (34 °C). Supplementation of the Se-NPs and RF in the diets significantly (p < 0.01) enhanced growth performance (weight gain, feed efficiency ratio, protein efficiency ratio, and specific growth rate), anti-oxidative status and immunity of the fish. Nitroblue tetrazolium (NBT), total immunoglobulin, myeloperoxidase and globulin enhanced (p < 0.01) with supplementation (Se-NPs + RF) whereas, albumin and albumin globulin (A:G) ratio (p < 0.01) reduced. Stress biomarkers such as lipid peroxidation in the liver, gill and kidney, blood glucose, heat shock protein 70 in gill and liver as well as serum cortisol reduced (p < 0.01) with supplementation of Se-NPs and RF, whereas, acetylcholine esterase and vitamin C level in both brain and muscle significantly enhanced (p < 0.01) in compared to control and stressors group (As + T) fed with control diet. The fish were treated with pathogenic bacteria after 90 days of experimental trial to observe cumulative mortality and relative survival for a week. The arsenic concentration in experimental water and bioaccumulation in fish tissues was also determined, which indicated that supplementation of Se-NPs and RF significantly reduced (p < 0.01) bioaccumulation. The study concluded that a combination of Se-NPs and RF has the potential to mitigate the stresses of high temperature and As pollution in P. hypophthalmus.

Chromium (Cr), one of the most abundant and hazardous heavy metals, is generally observed to be widely distributed in environment, primarily due to the inter-mixing of the untreated domestic and industrial wastewaters. There has been an increased interest to replace conventional centralized treatment technologies with the low energy, low cost, and zero sludge producing decentralized constructed wetland technology. Therefore, a long-term investigation on the comparative metal removal efficiency of the experimental vertical sub-surface flow (VSSF) constructed wetland systems, irrigated with Cr-spiked ground waters, under both mono and mixed-culture conditions planted with five different macrophytes viz. Typha (T), Phragmites (P), Acorus (V), Arundo (A), and Vetiver (K), in as mono- and {viz. (TP), (PA), (KV), (AT), and (VT)} as co-cropped combinations along with unplanted (U) systems as controls was conducted at the ICAR-Indian Agricultural Research Institute, New Delhi, India. Long-term investigations revealed significant differences between metal removal efficiencies of the planted (61.6% to 78.5%) and the unplanted systems (32.8% to 47.9%). However, these long-term average metal removal efficiencies were found to be insignificantly different for the mono (78.5%) and the co-cropped systems (77.6%). On further compartmentalization of the experimental wetland system's Cr-removal efficiencies amongst the major components viz. plant, microbe, and substrate, it was observed that vegetation contributed the maximum (i.e., 33-48%) while the microbes and the substrate contributed only 4-20% and 8-28%, respectively. It was further observed that due to reduced microbial diversity under unplanted conditions, the planted systems were associated with 2-7% higher microbial and equivalently lower substrate removal efficiencies. Thus, microbial activity-mediated metal mobilization and plant uptake were observed to be the principal processes governing Cr removal in the test VSSF constructed wetland systems exposed to varying Cr concentrations. Amongst all test macrophytes and their combinations, Arundo (81.9%) and Acorus (84.5%) based monocropped systems and Arundo+Typha (89.3%) based co-cropped systems emerged to be the most superior Cr-removing systems. Graphical abstarct.

An experiment was designed to delineate the efficacy of a dietary mixture of selenium nanoparticles (Se-NPs) and riboflavin (RF) on the thermal efficiency/tolerance of Pangasianodon hypophthalmus reared under arsenic (2.8 mg/L) and high-temperature (34 °C) stress. A green synthesis method was employed for the synthesis of Se-NPs using fish gills, which are normally discarded as by-products. Four isocaloric and iso-nitrogenous experimental diets were used, namely, a control diet (Se-NPs and RF @ 0 mg/kg diet) and diets containing RF @ 5, 10 or 15 mg/kg diet and Se-NPs @ 0.5 mg/kg diet, and feeding was performed for 95 days. At the end of the feeding trial, the thermal tolerance was evaluated by determination of the following parameters: critical thermal minimum (CTMin), lethal thermal minimum (LTMin), critical thermal maximum (CTMax), and lethal thermal maximum (LTMax). The anti-oxidative status in the form of catalase (CAT), glutathione-s-transferase (GST) and glutathione peroxidase (GPx) activities was significantly (p < 0.01) enhanced upon concurrent exposure to arsenic and high temperature at LTMin and LTMax, whereas a non-significant (p > 0.05) change in superoxide dismutase (SOD) activity was observed in the brain at LTMin and brain, gill and kidney at LTMax. Supplementation with Se-NPs @ 0.5 mg/kg diet and RF @ 5, 10 or 15 mg/kg diet significantly (p < 0.01) improved the anti-oxidative status with or without stressors. AChE activity in the brain was significantly (p < 0.01) inhibited upon concurrent exposure to arsenic and high temperature and improved in the treatment group supplemented with Se-NPs and RF. The arsenic concentration in muscle and experimental water and Se concentration in muscle and experimental feed were analysed. Overall, the results indicated that supplementation with RF @ 5 mg/kg diet and Se-NPs @ 0.5 mg/kg diet could confer protection to the fish against arsenic and thermal stress and led to enhanced thermal efficiency/tolerance of P. hypophthalmus.

Unexpected fluctuations in weather parameters due to global climate change have been observed in all ecosystems worldwide. The aquatic ecosystem shelters a great diversity of fishes in the upper region of the ecosystem which adversely get affected due to their poikilothermic nature. The present study was designed to elucidate the impact of critical temperature minima (CTMin), lethal temperature minima (LTMin), critical temperature maxima (CTMax), and lethal temperature maxima (LTMax) on Channa striatus. Biologically synthesized silver nanoparticles (Ag-NPs) were evaluated for their potential to enhance thermal tolerance and improve the activities of biochemical enzymes of C. striatus reared under lead (Pb) and high temperature (34 °C) for 50 days. Three iso-caloric and iso-nitrogenous diets which included a basal diet and two supplemented diets with Ag-NPs @ 0.5 mg/kg, and 1 mg/kg were used in the study. Results suggested that CTMin and LTMin were significantly (p < 0.01) reduced and CTMax and LTMax were enhanced in the group fed with 0.5 mg/kg Ag-NPs supplemented feed. Pre-exposure to high temperature led to enhanced CTMax and LTMax in C. striatus. The biochemical enzymes involved in protein metabolism, carbohydrate metabolism, acetylcholine esterase and antioxidant activities were found to be normal in fish fed with 0.5 mg/kg Ag-NPs supplemented diet. Bioaccumulation of silver and Pb was determined in different fish tissues and experimental water. Overall, the incorporation of Ag-NPs at 0.5 mg/kg in diet can confer protection to fish against Pb and thermal stress and enhance thermal tolerance of C. striatus.

The abiotic and biotic stress is an episode that effect on regulatory, neuro-endocrine and immune systems of animals including fish. The stress creates stimulatory and suppressive of immune system resulting in increases the incidence of infection. In view of these points, we have conducted an experiment to mitigate the stress through a nutritional approach through Zinc (Zn) supplementation in Pangasius hypophthalmus (initial weight-3.65 ± 0.75 g). Three isocaloric and isonitrogenous diets with graded levels of zinc 0, 10 and 20 mg/kg were prepared and fed to seven different groups with each in triplicate. The experimental group as follows as normal water with control diet (Ctr/Ctr), lead (Pb) exposed and fed with control diet (Ctr/Pb), control diet and exposed to Pb and temperature (Ctr/Pb-T), Zn 10 mg/kg fed without stressors (Zn- 10 mg/kg), Zn 20 mg/kg fed without stressors (Zn-20 mg/kg), Zn 10 mg/kg fed and Pb and temperature exposed (Pb-T/Zn 10 mg/kg) and Zn 20 mg/kg fed and exposed to Pb and temperature (Pb-T/Zn 20 mg/kg). The Pb in treated water was maintained at the level of 1/20th of LC50 (4 ppm) and temperature at 34 °C in exposure groups. The neutraceuticals role of dietary Zn was studied in terms of antioxidative enzymes (catalase, superoxide dismutase, glutathione-S-transferase), stress markers (Heat shock protein 70, cortisol, acetylcholine esterase, blood glucose, Vitamin C), immunological parameters (Total protein, albumin, globulin, A/G ratio and NBT) and subsequent challenge with Aeromonas veronii biovar sobria. The antioxidative enzymes, stress markers, albumin were significantly (p < 0.01) elevated, brain AChE and immuno-hematological parameters were significantly (p < 0.01) decreased due to lead (Pb) and temperature exposure. The relative survival (%) was reduced due to the concurrent effect of Pb, high temperature stress and bacterial challenge. Zinc at the rate of 10 and 20 mg/kg was found to be restore the biochemical and immunological parameters against concurrent exposure to lead (Pb), temperature and pathogenic infection. Results obtained in the present study indicate that supplementation of 10 and 20 mg/kg of Zn in the diet has a definitive role in the mitigation of lead (Pb) and temperature exposure along with pathogenic infection in P. hypophthalmus.

1 Centre for Environment Science and Climate Resilient Agriculture, ICAR-Indian Agricultural Research Institute, New Delhi-110012, India 2 School of Edaphic Stress Management, ICAR-National Institute of Abiotic Stress Management, Malegaon, Baramati-413115, Pune, Maharashtra, India 3 Water Technology Centre, ICAR-Indian Agricultural Research Institute, New Delhi-110012, India 4 Division of Microbiology, ICARIndian Agricultural Research Institute, New Delhi-110012, India 5 Division of Statistical Genetics, ICAR-Indian Agricultural Statistics Research Institute, New Delhi-110012, India

A number of black box and process-based modelling approaches, their strengths/limitations, and future applications for simulating contaminant dynamics in constructed wetlands (CWs) have been reviewed. Scanning of literature reveals that most of the CW modelling approaches are limited to the simulation of only nutrient and organic pollutant load dynamics. Performance analysis of the various process/black box-based models for simulating pollutant dynamics in vertical subsurface flow, horizontal subsurface flow, and hybrid CW systems further reveals that most of the existing modelling approaches have not not so far been able to account for the changing climatic conditions and the heavy metal dynamics. The paper thus highlights the gaps in the knowledge in the current state of the art for simulating wetland pollutant dynamics and suggests mechanisms for increasing the scope of such modelling approaches in the proper design and operation of the CW systems.

A preliminary study was conducted to delineate the ameliorating effect of dietary zinc nanoparticles (Zn-NPs) against thermal stress in Pangasius hypophthalmus reared under concurrent exposure to lead (Pb) and elevated temperature (34°C). Three diets were formulated such as control (no Zn-NPs), Zn-NPs 10 and 20mg/kg diet. Two hundred and thirty four fish were randomly distributed in to six treatments groups in triplicates; such as control group (no Zn-NPs in diet and unexposed to Pb and temperature, Ctr/Ctr), control diet with concurrent exposure to Pb and temperature (Pb-T/Ctr), Zn-NPs 10 and 20mg/kg without stressors (Zn-NPs 10mg/kg, Zn-NPs 20mg/kg), Zn-NPs 10 and 20mg/kg diet with concurrent exposure to Pb and temperature (Pb-T/Zn-NPs 10mg/kg, Pb-T/Zn-NPs 20mg/kg). The Pb in treated water was maintained at the level of 1/21th of LC50 (4ppm) at 34 °C temperature in stressors groups. Post 60 days feeding trial, critical thermal minimum (CTmin), lethal thermal minimum (LTmin), and critical thermal maximum (CTmax), lethal thermal maximum (LTmax) and biochemical attributes on P. hypophthalmus were evaluated. The results indicated that, dietary supplementation of Zn-NPs increased the CTmin, LTmin and CTmax, LTmax in P. hypophthalmus. Positive correlations were observed between CTmin LTmin (Y = − 0.495 + 10.08x, R2, 0.896) and CTmax LTmax (Y = − 0.872 + 4.43x, R2, 0.940). At the end of the thermal tolerance study, oxidative stress and lipid peroxidation (LPO) were significantly reduced and neurotransmitter enzyme was significantly increased in the groups fed with Zn-NPs @ 10mg and 20mg/kg diet. Overall results indicated that dietary Zn-NPs can confer protection against thermal stress in P. hypophthalmus.

Climate change and pollution are the most vulnerable stressors that are anticipated increasingly to affect all living organisms including fishes. The aquatic ecosystems are the most affected ecosystem due to contamination and global increasing temperature. In view of the above, the present study delineates 96-h median lethal concentration of heavy metal, lead alone and in combination with high temperature (34 °C) by conducting static non-renewable acute toxicity bioassay in Pangasius hypophthalmus (average weight 3.65 ± 0.75 g). Further, the effect of different definitive doses (80, 82, 84, 86, 88 and 90 mg/L) of lead alone and high temperature on cellular metabolic response was probed. The LC50 of lead was found to be 84.93 mg/L, whereas in combination with high temperature it was 83.10 mg/L in P. hypophthalmus. Catalase, superoxide dismutase and glutathione-S-transferase were noticeably higher (p < 0.01) in liver, gill and brain during lead exposure alone and in combination with high temperature. The activities of aspartate aminotransferase and alanine aminotransferase were significantly enhanced (p < 0.01) in muscle, liver and gill in dose- and time-dependent manners in lead-alone-exposed and in combination with high-temperature groups. The brain and liver acetylcholine esterase activities showed noticeable (p < 0.01) inhibition from 80 to 90 mg/L exposure of lead alone and with concurrent exposure to temperature than the control group. Overall results clearly indicate that acute exposure of lead and high temperature led to pronounced deleterious alterations on cellular and metabolic activities of P. hypophthalmus.