Toxicity and deleterious impacts of selenium nanoparticles at supranutritional and imbalance levels on male goldfish (Carassius auratus) sperm

Selenium toxicity in fishes: A current perspective

Anthropogenic activities have led to increased levels of contaminants that pose significant threats to aquatic organisms, particularly fishes. One such contaminant is Selenium (Se), a metalloid which is released by various industrial activities including mining and fossil fuel combustion. Selenium is crucial for various physiological functions, however it can bioaccumulate and become toxic at elevated concentrations. Given that fishes are key predators in aquatic ecosystems and a major protein source for humans, Se accumulation raises considerable ecological and food safety concerns. Selenium induces toxicity at the cellular level by disrupting the balance between reactive oxygen species (ROS) production and antioxidant capacity leading to oxidative damage. Chronic exposure to elevated Se impairs a wide range of critical physiological functions including metabolism, growth and reproduction. Selenium is also a potent teratogen and induces various types of adverse developmental effects in fishes, mainly due to its maternal transfer to the eggs. Moreover, that can persist across generations. Furthermore, Se-induced oxidative stress in the brain is a major driver of its neurotoxicity, which leads to impairment of several ecologically important behaviours in fishes including cognition and memory functions, social preference and interactions, and anxiety response. Our review provides an up-to-date and in-depth analysis of the various adverse physiological effects of Se in fishes, while identifying knowledge gaps that need to be addressed in future research for greater insights into the impact of Se in aquatic ecosystems.

Selenium Nanoparticles: Revolutionizing Nutrient Enhancement in Aquaculture - A Review

Aquaculture, a cornerstone of global food production, confronts myriad challenges including disease outbreaks and environmental degradation. Achieving nutritionally balanced aquafeed is critical for sustainable production, prompting exploration into innovative solutions like selenium nanoparticles (SeNPs). SeNPs offer potent antimicrobial, antioxidant, and growth-promoting properties, bolstering gut immunity and digestive capacity in aquatic animals. Their high bioavailability and ability to traverse gut barriers make them promising candidates for aquafeed supplementation. This study investigates SeNPs as a cutting-edge solution to enhance nutrient supply in aquaculture, addressing key challenges while promoting environmental stewardship and food security. By synthesizing current research and highlighting future directions, this review provides valuable insights into sustainable aquaculture practices. SeNPs hold promise for revolutionizing aquaculture feed formulations, offering a pathway to improved production outcomes and environmental sustainability.

Effect of Dietary Selenium on the Growth and Immune Systems of Fish

Dietary selenium (Se) is an essential component that supports fish growth and the immune system. This review attempts to provide insight into the biological impacts of dietary Se, including immunological responses, infection defense, and fish species growth, and it also identifies the routes via which it enters the aquatic environment. Dietary Se is important in fish feed due to its additive, antioxidant, and enzyme properties, which aid in various biological processes. However, excessive intake of it may harm aquatic ecosystems and potentially disrupt the food chain. This review explores the diverse natures of dietary Se, their impact on fish species, and the biological methods for eliminating excesses in aquatic environments. Soil has a potential role in the distribution of Se through erosion from agricultural, industrial, and mine sites. The research on dietary Se's effects on fish immune system and growth can provide knowledge regarding fish health, fish farming strategies, and the health of aquatic ecosystems, promoting the feed industry and sustainable aquaculture. This review provides data and references from various research studies on managing Se levels in aquatic ecosystems, promoting fish conservation, and utilizing Se in farmed fish diets.

Persistent organic pollutants influence the marine benthic macroinvertebrate assemblages in surface sediments of Nayband National Park and Bay, Northern Persian Gulf, Iran

Macroinvertebrate communities have been influenced by chemical substances, originated from petrochemical developments, that caused many problems in the marine biota. This study investigated the surface sediments of Nayband National Park and Bay (northern Persian Gulf) for polycyclic aromatic hydrocarbons (PAHs) and total petroleum hydrocarbons (TPHs) in terms of their distribution, source, and impacts on benthic macroinvertebrate assemblages. To this end, a total of 180 surface sediment samples from 20 stations were collected using Van-Veen grab sampler during winter 2018. The concentration of PAHs, TPHs, total organic carbon (TOC). and total organic matter (TOM) were evaluated, and grain size measurements were conducted on sediment samples in this study. Benthic macroinvertebrates were then identified in terms of presence and distribution. The results indicated that coarse granulometric fractions of sands were prevalence in all samples stations. The total concentration of PAHs ranged from 47.57 to 657.68 ng/g and TPHs 5.72 to 42.16 µg/g dw. The risk of ΣPAHs and TPHs in the sediments was relatively low to moderate according to the sediment quality guidelines. Analysis of the results revealed a significant negative correlation between ΣPAHs (R-value =  - 0.917; P < 0.01), TPHs (R-value =  - 0.849; P < 0.01) and macrofaunal abundance. Findings demonstrated that the species richness and abundance were at the lowest levels in stations where concentrations of PAHs, TPHs, TOC, and TOM were in the highest values, suggesting that these contaminants could negatively influence the benthic organisms in Nayband National Park and Bay. The results of correspondence analysis (CA) and principal component analysis (PCA) analysis showed that sedimentary habitats in Nayband National Park and Bay are being negatively affected by PAHs and TPHs, released from Pars Special Economic Energy Zone (PSEEZ). Moreover, the marine biotic index (AMBI) and Shannon-Weiner Diversity (H') results suggest that Nayband National Park and Bay can be classified as slightly to moderate polluted area. In conclusion, Northern Persian Gulf is significantly affected by oil industry developments and petrochemical activities. The unique ecosystem like Nayband National Park and Bay has been in a cautious status in terms of the PSEEZ pollutants and the levels of PAHs and TPHs concentration, warning that urgent environmental programs should be considered to protect the diversity and ecology of this valuable marine systems.

Hydrochemical evaluation of groundwater quality and human health risk assessment of trace elements in the largest mining district of South Khorasan, Eastern Iran

The groundwater resources of mining areas have been in a challenging condition in terms of metal pollution and human health. Therefore, this study investigated the concentration of cobalt (Co), molybdenum (Mo), selenium (Se), tin (Sn), and antimony (Sb) in groundwater samples (wells, qanats, and springs) in a heavily contaminated mining district, South Khorasan, Eastern Iran. Human health risk of the studied metals to target groups was assessed, and water quality of the studied groundwater was investigated in the study area. A total of 367 sampling sites (279 wells, 74 qanats, and 14 springs) in South Khorasan Province were selected to collect the groundwater samples from June to July 2020. Sampling was performed thrice for each sampling point, and hydrochemical parameters were evaluated using a portable multiparameter. Inductively coupled plasma mass spectrometry (ICP-MS) was used to detect the metal concentrations. Results showed an order of Se > Mo > Sn > Co > Sb, and hazard index (HI) demonstrated a warning condition for south of South Khorasan (drinking application), southwest of South Khorasan (Irrigation application), and east and center of South Khorasan (drinking-irrigation application). Hydrochemical parameters showed a classification of "Na + K type" and "Mixed Ca-Mg-Cl type" with an overall group of "Na-Cl-HCO3" for sampled waters. Ficklin-Caboi diagram depicted a classification of "near-neutral low metal," and Schoeller diagram classified studied groundwater as "good" for drinking and irrigation consumptions and "Na-Cl" type based on ion balance diagram. Based on the correlation analysis, positive relationships were recorded among EC, TDS, Cl-, Na+, sulfate, Ca2+, salt, total hardness, Mg2+, ammonia, and K+ measured in the water samples. In essence, arid regions of the world greatly rely upon groundwater resources for drinking and irrigation consumptions, and mining districts with a heavy load of active mines can be a serious threat to the groundwater quality and human health.

In silico modeling of the antagonistic effect of mercuric chloride and silver nanoparticles on the mortality rate of zebrafish (Danio rerio) based on response surface methodology

In this study, in silico modeling was designed to examine the antagonistic effect of mercuric chloride (HgCl₂) and silver nanoparticles (AgNPs) on the mortality rate of zebrafish (Danio rerio) based on response surface methodology (RSM). Adult zebrafish (Danio rerio) with an average weight of 0.75 ± 0.16 g were used in this study. An interaction between HgCl₂ and AgNPs was evaluated using DLS, TEM, and EDX mapping. In addition, RSM was applied to determine and predict the mortality rate of zebrafish induced by HgCl₂ in the presence of non-lethal concentrations of AgNPs and to optimize dependent and independent variables. Following exposure to HgCl₂, in vitro observations showed an increase in the hydrodynamic size of AgNPs and the formation of irregular nanoparticles. EDX mapping analysis also demonstrated the deposition of Hg ions on the surface of AgNPs, indicating the interaction between HgCl₂ and AgNPs (i.e., the amalgamation of Hg and AgNPs). Moreover, in silico and in vivo findings illustrated that the mortality rate of zebrafish increased significantly in a concentration-dependent manner; however, the mortality rate reduced greatly in the presence of AgNPs during 96-h exposure. Statistically significant correlation and regression were also observed for the mortality rate between the actual and predicted values based on the ANOVA results, showing that the proposed model fits well. The most critical conditions of mortality rate were occurred by HgCl₂ concentration of 0.23 mg L^-1 and AgNP concentration of 0.04 mg L^-1 that yielding maximum fish mortality rate of 96.541%. Additionally, the obtained value for model desirability was equal to 1.000 (i.e., the highest possible value). In conclusion, this statistical model could accurately describe the relationship between independent and dependent variables, and consequently boost substantially the experimental design of ecotoxicological studies by reducing the number of model organisms, toxic and chemical substances, time, and budget.

Toxicity Effects of Engineered Iron Nanoparticles (Fe3O4) on the Growth, Cell Density, and Pigment Content of Chlorella vulgaris

This study investigated the effects of Fe₃O₄ nanoparticles released from synthesized thiourea catalyst on the biological aspects of Chlorella vulgaris. Fe₃O₄ concentrations (0, 10, 100, 250, 500, 750, and 1000 mg L^-1) were used for the exposure tests. Biological parameters of C. vulgaris, including cell density, cell viability, and pigment content, were assessed. Bioconcentration and bioaccumulation factors were evaluated for contaminated microalgae. Non-carcinogenic risks were then assessed using target hazard quotient (THQ) for potential risks in human consumptions. Findings showed that C. vulgaris cell number increased from 0 to 500 mg L^-1 of Fe₃O₄ concentration. Chlorophyll a represented a time-dependent response, and greatest values were detected in 250 and 500 mg L^-1 Fe₃O₄ at 4.2 and 4 mg/g, respectively. Chlorophyll b content showed a time-related manner in exposure to Fe₃O₄ with the highest values recorded at 250 mg L^-1 after 96 h. Moreover, bioaccumulation displayed a dose-dependent response at 15,000 µg/g dw in 1000 mg L^-1, whereas the lowest concentration was in the control group at 1700 µg/g dw. The bioconcentration factor showed a concentration-relevant decrease in all iron treatments and 10 mg L^-1 of Fe₃O₄ represented the greatest BCF at 327.3611. Non-carcinogenic risks illustrated negligible hazard (THQ < 1) and the largest EDI and THQ were calculated in 1000 mg L^-1 at 7.4332E-07 (mg kg^-1 day^-1) and 1.06189E-09, respectively. Together, iron is an essential trace element for biological purposes in aquatic systems, but in exceeding concentrations could impose toxicity effects to C. vulgaris populations.

Selenium Nanoparticles as a Natural Antioxidant and Metabolic Regulator in Aquaculture: A Review

Balanced aquafeed is the key factor for enhancing the productivity of aquatic animals. In this context, aquatic animals require optimal amounts of lipids, proteins, carbohydrates, vitamins, and minerals. The original plant and animals' ingredients in the basal diets are insufficient to provide aquafeed with suitable amounts of minerals. Concurrently, elements should be incorporated in aquafeed in optimal doses, which differ based on the basal diets' species, age, size, and composition. Selenium is one of the essential trace elements involved in various metabolic, biological, and physiological functions. Se acts as a precursor for antioxidative enzyme synthesis leading to high total antioxidative capacity. Further, Se can enhance the immune response and the tolerance of aquatic animals to infectious diseases. Several metabolic mechanisms, such as thyroid hormone production, cytokine formation, fecundity, and DNA synthesis, require sufficient Se addition. The recent progress in the nanotechnology industry is also applied in the production of Se nanoparticles. Indeed, Se nanoparticles are elaborated as more soluble and bioavailable than the organic and non-organic forms. In aquaculture, multiple investigations have elaborated the role of Se nanoparticles on the performances and wellbeing of aquatic animals. In this review, the outputs of recent studies associated with the role of Se nanoparticles on aquatic animals' performances were simplified and presented for more research and development.

Selenium Nanomaterials to Combat Antimicrobial Resistance

The rise of antimicrobial resistance to antibiotics (AMR) as a healthcare crisis has led to a tremendous social and economic impact, whose damage poses a significant threat to future generations. Current treatments either are less effective or result in further acquired resistance. At the same time, several new antimicrobial discovery approaches are expensive, slow, and relatively poorly equipped for translation into the clinical world. Therefore, the use of nanomaterials is presented as a suitable solution. In particular, this review discusses selenium nanoparticles (SeNPs) as one of the most promising therapeutic agents based in the nanoscale to treat infections effectively. This work summarizes the latest advances in the synthesis of SeNPs and their progress as antimicrobial agents using traditional and biogenic approaches. While physiochemical methods produce consistent nanostructures, along with shortened processing procedures and potential for functionalization of designs, green or biogenic synthesis represents a quick, inexpensive, efficient, and eco-friendly approach with more promise for tunability and versatility. In the end, the clinical translation of SeNPs faces various obstacles, including uncertain in vivo safety profiles and mechanisms of action and unclear regulatory frameworks. Nonetheless, the promise possessed by these metalloid nanostructures, along with other nanoparticles in treating bacterial infections and slowing down the AMR crisis, are worth exploring.