Effects of humic acid on nutrient removal efficiency of aquatic duckweed (Lemna minor) and both growth performance, and hemato-biochemical parameters of Nile tilapia (Oreochromis niloticus) cultured in water recirculating system.

This study was carried out to evaluate the effects of humic acid (HA) on the nutrient removal efficiencies of aquatic duckweed plant (Lemna minor) from a water recirculating system used to culture Nile tilapia (Oreochromis niloticus) fish for 30 days. The HA was added to water at three concentrations of 0 (Control), 1.5, and 3 mg/L in triplicate. Water quality parameters, growth performance, and some hemato-biochemical parameters of the fish in variable HA concentrations were compared. The total ammonia nitrogen (TAN) and total phosphorous (TP) removal efficiency of L. minor increased with increasing the HA concentration from 0 mg/L to 3 mg/L (p < 0.05). The concentration of nitrate (NO3-) in the HA-3 mg/L was higher than that in the other groups on days 20 and 30 of the fish cultivation period (p < 0.05). The growth performance of fish improved in the HA-3 mg/L compared to the other groups. The addition of different concentrations of HA to water had no adverse effect on the hematological properties of the Nile tilapia. The plasma aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP) levels in the HA-0 mg/L and HA-1.5 mg/L groups were higher than in the HA-3 mg/L (p < 0.05). No significant differences in the plasma glucose and cholesterol levels were observed between the HA-groups (p > 0.05), while the triglyceride level increased in the HA-3 mg/L compared to the control (p < 0.05). These results indicated that adding HA to water could be an effective method to enhance the bioremediation performance of the aquatic duckweed plants as biofilter and thus improve water quality, subsequently, fish growth performance in RASs.

The current study applied aquatic duckweed plant (Lemna minor) as a new biofilter in a water recirculating system used to culture Nile tilapia (Oreochromis niloticus) fish. The effects of three concentrations of humic acid (HA) as water additive on the nutrient removal efficiency of L. minor from water were investigated. HA improved bioremediation performance of the aquatic duckweed plant.

Acute toxicity of nanoscale zeolitic imidazolate framework 8 (ZIF-8) to saltwater planktonic species Artemia salina and Nannochloropsis oculata.

Zeolitic imidazolate framework-8 nanoparticles (ZIF-8 NPs) are metal-organic frameworks (MOFs) that have gained significant attention in various fields due to their unique properties. They have potential applications in drug delivery, gas storage, and catalysis. However, their increasing use raises concerns about their potential environmental impact. Our study evaluates the effects of ≈90 nm ZIF-8 NPs in two planktonic species, the green microalga Nannochloropsis oculata and the brine shrimp Artemia salina. After synthesis and characterization (SEM, EDS, BET, and DLS) of nanoporous ZIF-8 NPs, a growth inhibition test on microalgae (72 h) and acute immobilization test on instar I and II of Artemia nauplii (48 h) were conducted following, OECD 201 and ISO/TS 20787, respectively. The toxicity of ZIF-8 NPs to both species was time- and concentration-dependent. The 72-h median inhibitory concentration (IC50) of ZIF-8 NPs for N. oculata based on average specific growth rate and yield were calculated as 79.71 ± 8.55 mg L-1 and 51.73 ± 5.16 mg L-1, respectively. Also, the 48-h median effective concentration (EC50) of ZIF-8 NPs on immobilization rate of instar I and II were calculated as 175.09 ± 4.14 mg L-1 and 4.69 ± 0.34 mg L-1, respectively. Moreover, the swimming type of non-immobilized animals was affected by ZIF-8 NPs. These findings provide a good insight into the toxicity of nanoparticulate ZIF-8 to saltwater planktons and also confirm that instar II Artemia is more sensitive than instar I. This study demonstrated that ZIF-8 NPs, despite all their advantages, could have toxic effects on aquatic organisms. More studies are required to assess their potential environmental impact and develop strategies to mitigate their toxicity.

Application of alginate-immobilized microalgae beads as biosorbent for removal of total ammonia and phosphorus from water of African cichlid (Labidochromis lividus) recirculating aquaculture system.

Immobilized microalgae are a promising approach to incorporate microalgae in recirculating aquaculture system (RAS) for water purification. In the present study, two types of biosorbents including sodium alginate-immobilized Scenedesmus spp. and Chlorella spp. beads (algal beads) and sodium alginate beads without microalgae (alginate beads) were prepared. In the first experiment (static test), the potential of two biosorbents to remove different concentrations of total ammonia nitrogen (TAN) and total phosphorus (TP) from water was investigated. In the second experiment, two prepared biosorbents were used as biofilter in a RAS for rearing African cichlid (Labidochromis lividus) for 30 days. The survival rate and growth indices of fingerling fish and removal efficiency of two biosorbents for TAN, NO3-N, and TP were determined. The results of static test showed that the removal efficiency and uptake capacity of the two biosorbents for TAN and TP increased during 30 days of the experiment, and these values for the algal beads were higher than the alginate beads. The TAN removal efficiency of the two biosorbents increased with increasing TAN concentration from 0.5 to 5 mg L-1. The application of algal beads in the RAS improved the survival rate, final weight, final length, weight gain, and daily growth index (DGI%) indices of fish compared to those cultured in the RAS containing the alginate beads and the control (P<0.05). The algal and alginate beads decreased the TAN concentration by 42.85% and 28.57% compared to the control after 30 days of cultivation period, respectively. The uptake of nitrate was not observed by the two biosorbents during cultivation period. The TP removal efficiency of algal beads reached 44.90% after 30 days. The findings of this study indicated that the sodium alginate-immobilized microalgae could be considered as a suitable biofilter to be incorporated into a RAS to improve water quality and consequently enhance the growth and health of fish.

Cytotoxicity, oxidative stress, and apoptosis in human embryonic kidney (HEK293) and colon cancer (SW480) cell lines exposed to nanoscale zeolitic imidazolate framework 8 (ZIF-8).

Zinc (zeolitic) imidazolate framework 8 (ZIF-8) has been widely considered in the literature as an ideal candidate for drug delivery especially anti-cancer drugs. However, the available information on the biocompatibility and cytotoxicity of ZIF-8 nanoparticles is contradictory. Therefore, in the present study, the ZIF-8 particles were synthetized, characterized, and their potential toxicity on two eukaryotic cell lines including human embryonic kidney (HEK293) and human colon cancer (SW480) cells was investigated in vitro. The characterization of ZIF-8 particles by TEM, EDX, SEM, and DLS indicated the synthesis of the hexagonal crystals with mean diameter of 124.71±32.74 nm and the presence of the zinc element at 86.25% by weight (wt%) of the ZIF-8 structure. The results of the cytotoxicity assessment of ZIF-8 NPs showed that the viability of two different cell lines reduced significantly coincident with increasing exposure concentration from 0 to 500 µg mL-1 (P<0.05). The 24-h half-inhibitory concentration (IC50-24 h) values of ZIF-8 NPs for HEK293 and SW480 cell lines were 116.22 and 36.23 µg mL-1, respectively. We found that the viability of SW480 cells was significantly lower than the HEK293 cells in all exposure concentrations of ZIF-8 NPs except control. Exposure of both cells resulted in increasing of the intracellular reactive oxygen species (ROS) production and activation of apoptosis pathway. The apoptosis rate of cancer SW480 cells was higher than the normal HEK293 cells. These findings indicate that synthetized ZIF-8 NPs could be a candidate for cancer therapy, although their toxic effects on the normal cells also should be considered.

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.

Comparative toxicity of nanoparticulate and ionic copper following dietary exposure to common carp (Cyprinus carpio).

Copper is an essential element for the normal growth and survival of all organisms including fish. However, its excessive presence in the environment can cause bioaccumulation and aquatic toxicology. The aim of the present study was to compare the dietary toxicity effects of two different Cu compounds, copper oxide nanoparticles (CuO-NPs) and ionic copper (CuSO4) in juvenile common carp, Cyprinus carpio. To prepare experimental diets, two nominal concentrations of 100 and 1000 mg Cu kg-1 diet were added to a basal diet. Carp (n = 450, average initial weight of 35.94 ± 5.35 g) were fed on the Cu-supplemented diets and basal diets for two 21-day courses as dietary exposure and recovery periods, respectively. The growth performance, survival rate and blood biochemical indices as well as copper accumulation in target organs of fish were investigated at the end of each exposure period. The results showed that the weight gain (WG) of carp significantly decreased coincident with increasing concentration of the both dietary Cu forms (P = 0.00). Both Cu sources at concentrations of 100 mg kg-1 diet decreased the survival rate of fish (P = 0.003), likely due to more feed intake and thus increased copper toxicity. The both forms of dietary Cu at two different concentrations significantly decreased the plasma glutamate oxaloacetate transaminase (GOT) level compared to the control group (P = 0.008). Fish exposed to diets containing Cu sources except 100 mg Cu kg-1 of CuO-NPs showed the lower glutamate pyruvate transaminase (GPT) activity in comparison to the control (P = 0.00). The plasma sodium level in1000 mg CuO-NPs kg-1 diet was significantly lower than the control (P = 0.001). The plasma potassium level increased in the all Cu-supplemented groups except 100 mg kg-1 of CuO-NPs after the dietary exposure period (P = 0.035). The copper accumulation was dose-dependent in all target organs. In 100 mg Cu kg-1 dietary groups, the liver showed the highest Cu accumulation (P = 0.00), while in 1000 mg Cu kg-1 dietary groups, the highest Cu content was observed in the intestine (P = 0.00). The results demonstrated the enhanced toxicological responses in fish after 21 days of dietary exposure, but the levels of most of biochemical indices and tissues Cu content decreased or returned to the control values after the recovery period.

On how environmental and experimental conditions affect the results of aquatic nanotoxicology on brine shrimp (Artemia salina): A case of silver nanoparticles toxicity.

The genus Artemia sp. has been accepted as a reliable model organism for aquatic toxicity and nanotoxicity experiments, as far as the ISO TS 20787 has recently been published to standardize nanotoxicity test with this organism. Experimental and environmental conditions may affect the toxicity of nanomaterials on aquatic organisms including Artemia sp. nauplii. In this study, acute toxicity effects of silver nanoparticles (AgNPs) on the nauplii of Artemia salina was investigated under various conditions (e.g. different lights, salinities, temperatures, volume and agitation of exposure media and instar stages of nauplii). The EC values were calculated using Probit program and all data were analyzed statistically by SPSS software. At all test conditions, the immobilization rate of Artemia nauplii increased in a concentration-dependent manner (P < 0.05). The sensitivity of instar stage II to different concentrations of AgNPs was significantly higher than instar I (P < 0.05). The toxicity effect of AgNPs was affected by alteration of environmental conditions, so that the effective concentration (EC) values for instar I of A. salina decreased with increasing water temperature, decreasing water salinity and in continuous darkness condition. The EC50 value of AgNPs was significantly lower in 100 mL beakers (21.35 ±â€¯5.67 mg L-1) than 10 mL well plates (42.44 ±â€¯11.30 mg L-1). Agitation of exposure media did not affect the toxicity of AgNPs. The results indicated that the experimental and environmental conditions influence on the toxicity of AgNPs in the nauplii of A. salina.

Will the antimicrobial properties of ZnONPs turn it into a more suitable option than AgNPs for water filtration? Comparative study in the removal of fish pathogen, Aeromonas hydrophila from the culture of juvenile common carp (Cyprinus carpio).

The purpose of this study was to investigate the possibility of using zinc oxide nanoparticles (ZnONPs) instead of silver nanoparticles (AgNPs) for removing Aeromonas hydrophila from water used to culture Cyprinus carpio juvenile. Antibacterial materials as filter media were prepared by coating ZnONPs (two coating methods, referred as ZnA and ZnB) or AgNPs (referred as Ag) on the porous surfaces of zeolite beads. The characterization of coated samples was determined using FESEM, EDS, and GFAAS. The antibacterial activities of prepared samples were evaluated by the zone of inhibition test, tube test, and flow test. The diameter of inhibitory zones formed by ZnONP- and AgNP-coated zeolite beads was significantly higher than uncoated zeolite (control) (P < 0.05). Also, the tube test results revealed 100% killing of the bacterial cells after 24 h of contact to all coated materials. In the flow test (without fish), the antibacterial efficiency of filter columns that contained ZnA, ZnB, and Ag found to be 34.84, 23.77, and 100% after 96 h, respectively. The mortality rate of carp juveniles cultured in infected water treated with AgNP filters was significantly lower than those cultured in infected water or treated with ZnONPs filters (P < 0.05). The results indicated that although ZnONP filter media have somewhat antimicrobial properties (especially in vitro), their ability to complete removal of microorganisms from the water is not as high as AgNP filters. So, it still seems that zeolite coated with AgNPs has a higher potential for water disinfection in aquaculture.

Dietary administration of ferula (Ferula asafoetida) powder as a feed additive in diet of koi carp, Cyprinus carpio koi: effects on hemato-immunological parameters, mucosal antibacterial activity, digestive enzymes, and growth performance.

This study investigated the impacts of various levels (0, 5, 10, 15, 20, and 25 g kg-1) of dietary ferula (Ferula asafoetida) powder (FP) on the hemato-immunological indices, antibacterial properties of skin mucus, survival rate, and growth performance as well as digestive enzyme activity of Koi carp, Cyprinus carpio koi, fingerlings. Following 63 days of feeding trail, WBCs, RBCs, Hb, hematocrit, MCV, MCH, MCHC, and lymphocyte levels increased coincident with an increasing FP level in experimental diets compared with control diet (P < 0.05). Dietary FP significantly increased total protein content and the activities of total immunoglobulins, lysozyme, and alternative hemolytic complement in a concentration-dependent manner in the serum of koi fish (P < 0.05). The elevation of the FP level in experimental diets resulted in an increase in SGR value and a reduction in FCR value (P < 0.05). The survival rate also increased significantly coincident with the increasing dietary FP level (P < 0.05). The results revealed that dietary ferula powder especially at levels of 20 and 25 g kg-1 could be used as an effective herbal dietary supplement in the enhancement of humoral innate immune responses and growth of koi carp.

Trophic transfer of CuO nanoparticles from brine shrimp (Artemia salina) nauplii to convict cichlid (Amatitlania nigrofasciata) larvae: uptake, accumulation and elimination.

We investigated the trophic transfer potential of CuO-NPs from Artemia salina to Amatitlania nigrofasciata. The Cu uptake was investigated by exposure of the instar II nauplii to 0, 1, 10, and 100 mg/L CuO-NPs for 4 h. Dietborne exposure of fish larvae to CuO-NPs was done for 21 days through feeding with pre-exposed nauplii. Thereafter, all survived fish were fed for 21 more days with non-contaminated nauplii. The results showed that NPs could be taken up by nauplii in a concentration-dependent manner. The highest uptake of Cu by nauplii was found to be 50.5 ± 1.4 mg/g dry weight at 100 mg/L. The copper accumulation in fish larvae increased significantly with increasing Cu content in pre-exposed nauplii to different concentrations of CuO-NPs (p < 0.05). At the end of the depuration phase, although the Cu elimination was significantly higher in fish that were fed with more contaminated nauplii, but the survival rate, average final weight, and length of those larvae was still significantly less than the control group (p < 0.05). The accumulated Cu after the depuration phase in cichlid larvae was 25.4 ± 0.5, 29 ± 8.0, 33.9 ± 9.7, and 42.3 ± 4.0 µg/g dry weight at 0, 1, 10, and 100 mg/L of CuO-NPs-treated Artemia. The current findings indicated the ability of manufactured CuO-NPs to be transferred from one trophic level to the next as assessed in the simple food chain consisting of pre-exposed A. salina and A. nigrofasciata.

Comparative toxicity of silver nanoparticles (AgNPs) and silver nanowires (AgNWs) on saltwater microcrustacean, Artemia salina.

This study evaluated the potential toxic effects of silver nanoparticles (AgNPs) and silver nanowires (AgNWs) on saltwater microcrustacean Artemia salina nauplii under ISO TS 20787 guideline. To investigate the acute toxicity of these nanomaterials, the nauplii were exposed to different concentrations of 0 (control), 0.39, 1.56, 6.25, 25 and 100 mg/L AgNPs and concentrations of 0 (control), 0.01, 0.1, 1, 10, 50 and 100 mg/L AgNWs for 72 h. Immobilization rate of A. salina exposed to both AgNPs and AgNWs for 72 h increased significantly in a concentration-dependent manner (P < 0.05). The 72 h EC10 and EC50 were found to be 1.48 ±â€¯0.6 and 10.70 ±â€¯1.3 mg/L for AgNPs, respectively, and 0.03 ±â€¯0.02 and 0.43 ±â€¯0.04 mg/L for AgNWs, respectively. Based on the EC10 and EC50 values, the toxicity of AgNWs was significantly higher than AgNPs (P < 0.05). Oxidative stress resulted from 48 h exposure to both AgNPs and AgNWs in A. salina was assessed by measuring reactive oxygen species (ROS) production and superoxide dismutase (SOD) activity. The results revealed that both AgNPs and AgNWs could induce ROS production. The SOD activity decreased significantly with the increase of exposure concentration (P < 0.05). In conclusion, the present results show that both nanomaterials have toxic effects on A. salina nauplii and thus, more effort should be made to prevent their release into saltwater ecosystems and trophic transfer in the aquatic food chain.

Dietary cosupplementation with curcumin and different selenium sources (nanoparticulate, organic, and inorganic selenium): influence on growth performance, body composition, immune responses, and glutathione peroxidase activity of rainbow trout (Oncorhynchus mykiss).

The aim of this study was to investigate the effects of dietary selenium (nanoparticles, organic, and inorganic forms), curcumin (CUR), and their combination on survival, growth performance, body composition, innate immune responses, and glutathione peroxidase activity of rainbow trout (Oncorhynchus mykiss). CUR at level of 400 mg/kg dry diet and each of selenium nanoparticles (Se-NPs), organic selenium (Sel-Plax®), and sodium selenite at level of 1 mg/kg Se dry diet were added to basal diet. A total of 240 rainbow trout with mean initial weight of 14.65 ± 0.86 g were fed eight diets including control (basal diet), CUR, Se-NPs, Se-NPs + CUR, organic Se, organic Se + CUR, sodium Se, and sodium Se + CUR for 8 weeks. No significant increase in survival rate, growth performance, feed utilization, and body composition was observed in fish-fed CUR and Se included diets compared to control (P > 0.05). The highest lysozyme and alternative hemolytic complement activity was observed in fish-fed CUR and organic Se + CUR-supplemented diets (P < 0.05). Fish-fed Se-NPs and Se-NPs + CUR-supplemented diets had the highest glutathione peroxidase activity (P < 0.05). The results of the present study indicated that the combination of CUR and Se in nanoparticles and organic forms was more effective in promoting innate immune responses of rainbow trout compared to the other combined or separated Se and CUR forms.

Dietary administration of eryngii mushroom (Pleurotus eryngii) powder on haemato-immunological responses, bactericidal activity of skin mucus and growth performance of koi carp fingerlings (Cyprinus carpio koi).

The aim of present study was to evaluate the effects of edible eryngii mushroom powder, Pleurotus eryngii (PE), for 63 days on haematological parameters, the serum immune responses, skin mucus, bactericidal activity, stress resistance, growth performance and digestive enzyme activities of Koi carp fingerlings (Cyprinus carpio koi). Fish were divided into five groups and each group was fed with dietary PE with five graded levels (0, 0.5, 1, 1.5 and 2%). The results showed a significant dose-dependent increase of Ht, Hb, MCV and MCH levels in fish fed dietary PE (P < 0.05). The highest levels of WBCs, lymphocytes and monocytes were measured in fish fed 1.5% and 2% of dietary PE (P < 0.05). The activities of total IG, lysozyme, Alternative haemolytic complement activity in serum of fish fed with 2% of dietary PE for 63 days as well as 5-min air exposure challenge test were significantly higher than other groups (P < 0.05). The most bactericidal activity was observed in skin mucus of fish fed with 1.5% of dietary PE against Streptococcus iniae (P < 0.05). The highest ratio of the lactobacillus count to the total viable count was observed in fish fed 2% of dietary PE. The α-amylase activity of fish fed with dietary PE (1, 1.5 and 2%) were significantly higher than control group (P < 0.05). Feeding fish 2% of dietary PE increased the trypsin and lipase activity compared to others groups (P < 0.05). The growth performance of fish fed 1.5% of dietary PE improved compared to control group (P < 0.05). The results revealed that feeding koi fish with dietary supplementation of PE (1.5 and 2%) improved the selected humoral innate immune responses, bactericidal activity of skin mucus and growth performance of koi fish.

Influence of salinity on the toxicity of silver nanoparticles (AgNPs) and silver nitrate (AgNO3) in halophilic microalgae, Dunaliella salina.

This study aim to evaluate the potential toxic effects of citrate coated silver nanoparticles (AgNPs) and ionic silver (AgNO3) on marine microalgae Dunaliella salina under three different salinities (35, 70, and 140 g/L). The toxicity was investigated according to modified OECD guideline (No. 201) by 72 h exposure of microalgae to various concentrations of each of the chemicals in Walne's saline media. According to the results, the growth inhibitory effects of AgNPs and AgNO3 increased significantly coincidence with increasing time and concentration compared to control (P < 0.05). The values of median inhibitory concentrations (IC50) of AgNPs and AgNO3 based on average specific growth rate and yield for D. salina increased significantly with elevation of water salinity from 35 to 140 g/L (P < 0.05). Toxicity of AgNO3 based on IC50 to D. salina was significantly higher than AgNPs at all salinities (P < 0.05). In conclusion, both AgNPs and AgNO3 inhibited the growth of D. salina at different saltwater medium.

Acute toxicity, uptake, and elimination of zinc oxide nanoparticles (ZnO NPs) using saltwater microcrustacean, Artemia franciscana.

This study aims to evaluate the potential toxic effects of ZnO nanoparticles on Artemia franciscana nauplii. The ZnO NPs suspension was characterized by TEM, EDS and DLS techniques. Acute toxicity was investigated by exposure of nauplii to concentrations of 1, 5, 7.5, 10, 15, 20, 25 and 30 mg/L of ZnO NPs for 48 h and 96 h. The 96-h EC10 and EC50 values of ZnO NPs were found to be 1.39 mg/L and 4.86 mg/L respectively. The ZnO NPs suspensions did not cause any significant acute toxicity after 48 h of exposure, but the immobilization rate increase significantly compare to control group after 96 h (P < 0.05). The results showed that the uptake, accumulation, and elimination of NPs in nauplii depends on the concentration of NPs and time. The elimination rates of 46.66% and 83.85% were recorded at 1 and 10 mg/L of NPs after 24 h of depuration period, respectively.