Hematological, biochemical and enzymological responses in an Indian major carp Labeo rohita induced by sublethal concentration of waterborne selenite exposure

Sub-chronic level FLX exposure and biomarker response in Labeo rohita

Selective serotonin reuptake inhibitors (SSRIs) are among the most widely prescribed psychotropic medications globally used to treat depression, anxiety disorders, and related mental health conditions. Among these, Fluoxetine (FLX), recognized by its brand name Prozac, is frequently used. SSRIs increase serotonin levels in the brain, inhibiting its reuptake to enhance mood and emotional stability. However, their widespread production, consumption, and eventual environmental release are raising concerns among aquatic toxicologists and environmental biologists due to their potential impact on ecosystems and human health. This study investigated the long-term (35-days) antioxidant responses in Labeo rohita fingerlings exposed to varying concentrations of FLX (1, 10, and 100 μg/L). Compared to control groups, the activity of superoxide dismutase (SOD) in the brain significantly decreased (P < 0.05) in FLX-treated fish, except at the highest (100 μg/L) concentration on the 35th day. Similarly, catalase (CAT) and glutathione S-transferase (GST) activity were significantly reduced (P < 0.05) across all treatments. Lipid peroxidation (LPO) levels were markedly elevated in FLX-treated fishes, signifying oxidative stress. Acetylcholinesterase activity in brain tissue decreased in FLX-treated groups. These findings provide critical baseline data for molecular toxicology, highlighting the potential effects of pharmaceutical pollutants on non-target aquatic organisms.

Acrylamide toxicity in aquatic animals and its mitigation approaches: an updated overview

Acrylamide (ACR) is widely applied in various industrial activities, as well as in the water purification process. Furthermore, ACR is synthesized naturally in some starchy grains exposed to high temperatures for an extended time during the cooking process. Because of its widespread industrial usage, ACR might be released into water stream sources. Also, ACR poses a high risk of contaminated surface and ground-water resources due to its high solubility and mobility in water. Furthermore, animal studies have indicated that ACR exposure may cause cancer (in many organs such as lung, prostate, uterus, and pancreas), genetic damage (in both somatic and germ cells), and severe effects on reproduction and development. Recently, numerous studies have shown that ACR has a mild acute cytotoxic impact on aquatic species, particularly during early life stages. Besides, wide-spectrum usage of ACR in many industrial activities presented higher environmental risks as well as major hazards to consumer health. This literature was designed to include all potential and accessible reports on ACR toxicity related with aquatic species. The Preferred Reporting Items for Systematic Reviews were applied to evaluate the risk effects of ACR on aquatic organisms, the ACR sub-lethal concentration in the ecosystem, and the possible protective benefits of various feed additives against ACR toxicity in fish. The major findings are summarized in Tables 2 and 3. The primary aim of this literature was to specify the hazards of ACR toxicity related with fish welfare and possible suggested strategies to reduce its risks.

Toxicological effect of endocrine disrupting heavy metal (Pb) on Mekong silurid Pangasius catfish, Pangasius hypophthalmus

The current study aimed to investigate the effects of lead nitrate exposure on the enzymatical, haematological, and histological changes in the gill, liver, and kidney of Pangasius hypophthalmus. The fish were divided into six groups and treated with different Pb concentrations. The LC50 value of Pb was 55.57 mg/L at 96 h for P. hypophthalmus, and sublethal toxicity was assessed for 45 days at 1/5th (11.47 mg/L) and 1/10th (5.57 mg/L) of LC50 concentration. Enzymes such as aspartate aminotransferase (AST), alanine aminotransferase (ALT) levels, alkaline phosphate (ALP), and lactate dehydrogenase (LDH) content increased significantly during sublethal toxicity of Pb. The reduction of HCT and PCV indicates an anemic condition due to the toxicity of Pb. Differential leucocytes, lymphocytes, and monocytes and their % values significantly decreased, indicating Pb exposure. The main histological changes observed in the gills were the destruction of secondary lamellae, the fusion of adjacent gill lamellae, primary lamellae hypertrophy, and severe hyperplasia, while in kidney exposed to Pb showed melanomacrophages, increased periglomerular, peritubular space, vacuolation, shrunken glomerulus, destruction of tubular epithelium, and hypertrophy of distal convoluted segment. The liver showed severe necrosis and rupture of hepatic cells, hyper trepheoid bile duct, shifting of nuclei, and vascular hemorrhage, while in the brain, binucleus, mesoglea cells, vacuole, and ruptured nucleus were observed. In conclusion, P. hypophthalmus, which has been exposed to Pb has developed a number of toxicity markers. Consequently, prolonged exposure to higher Pb concentrations may be harmful to fish health. The findings strongly suggest that the lead had a detrimental impact on the P. hypophthalmus population, as well as on the water quality and non-target aquatic organisms.

Insights into the mechanism of growth and fat deposition by feeding different levels of lipid provided by transcriptome analysis of swamp eel (Monopterus albus, Zuiew 1793) liver

Lipid is an important source of energy in fish feeds, and the appropriate fat content can improve the efficiency of protein utilization. However, excessive lipid content in the feed can lead to abnormal fat deposition in fish, which has a negative effect on the growth of fish. Therefore, the effects of feed lipid levels on swamp eel were studied. Essential functional genes were screened using transcriptomics. We divided 840 fish into seven groups (four replicates). A mixture of fish and soybean oils (1:4), 0%, 2%, 4%, 6%, 8%, 10%, and 12% was added to the basic feed were named groups one to seven (L1-L7), respectively. Isonitrogenous diets were fed swamp eel for 10 weeks. Growth performance, visceral index, nutritional components, and biochemical indexes were measured and analyzed. Livers of the 0%, 6%, and 12% groups were subjected to transcriptome sequencing analysis. The results of our study showed that: the suitable lipid level for the growth of swamp eel was 7.03%; the crude fat content of whole fish, liver, intestine, muscle, and skin increased with the increase of lipid level, with some significant difference, and excess fat was deposited in skin tissue; triglyceride, total cholesterol, and free fatty acid contents increased with the increase of feed lipid level. High-density lipoprotein levels in the L3 and L4 groups were higher than in the other groups. Blood glucose concentrations in the L5, L6, and L7 groups increased; the liver tissue structure was damaged when the lipid level was too high. two-hundred-and-twenty-eight differentially expressed genes were found. Several critical pathways regulating glucose metabolism and energy balance (e.g., glycerolipid metabolism, glycolysis synthesis, degradation of ketone bodies, and Janus Kinase/Signal Transducer and Activator of Transcription signaling pathway) were enriched in swamp eel compared with the Kyoto Encyclopedia of Genes and Genomes (KEGG) database. Suitable lipid levels (7.03%) can promote the growth of swamp eel, and excessive lipid levels can cause elevated blood lipids and lead to liver cell damage. Regulatory mechanisms may involve multiple metabolic pathways for glucose and lipid metabolism in eels. This study provides new insights to explain the mechanism of fat deposition due to high levels of lipid and provides a basis for the production of efficient and environmentally friendly feed for swamp eel.

The effect of acute toxicity from tributyltin on Liza haematocheila liver: Energy metabolic disturbance, oxidative stress, and apoptosis

Tributyltin (TBT), a highly toxic and persistent organic pollutant, is widely distributed in coastal waters. Liza haematocheila (L. haematocheila) is one of bony fish distributing coincident with TBT, and exposure risk of TBT to this fish is unknown. In this study, L. haematocheila was exposed to TBT of 0, 3.4, 6.8, and 17.2 μg/L for 48 h to explore hepatic response mechanism. Our results showed that Sn content in livers increased after 48 h of exposure. HSI and histological changes indicated that TBT suppressed liver development of L. haematocheila. TBT reduced ATPase activities. The increased RB in blood and the reduced TBC were measured after exposure to TBT. T-AOC and antioxidant enzymes SOD, CAT, and GPx activities were inhibited while MDA content was increased. Liver cells showed apoptosis characteristics after TBT exposure. Furthermore, transcriptome analysis of livers was performed and the results showed energy metabolism-related GO term (such as ATPase complex and ATPase dependent transmembrance transport complex), oxidative stress-related GO term (such as Celllular response to oxidative stress and Antioxidant activity), and apoptosis-related GO term (such as Regulation of cysteine-type endopeptidase activity involved in apoptosic signaling pathway). Moreover, we found six energy metabolism-related differentially expressed genes (DEGs) including three up-regulated DEGs (atnb233, cftr, and prkag2) and three down-regulated DEGs (acss1, abcd2, and smarcb1); five oxidative stress-related DEGs including one up-regulated DEG (mmp9) and four down-regulated DEG (prdx5, hsp90, hsp98, and gstf9); as well as six apoptosis-related DEGs including five up-regulated DEGs (casp8, cyc, apaf1, hccs, and dapk3) and one down-regulated DEG (bcl2l1). Our transcriptome data above further confirmed that acute stress of TBT led energy metabolic disturbance, oxidative stress, and apoptosis in L. haematocheila livers.

Impact of acute and sub-acute exposure of magnesium oxide nanoparticles on mrigal Cirrhinus mrigala

This experiment was conducted to investigate the impact of acute and sub-acute exposure of magnesium oxide nanoparticles on Mrigal Cirrhinus mrigala. For sub-acute tests 1/100,1/50,1/10 were selected based on the LC₅₀ at 96 h s. Protein, carbohydrate, and lipid, Aspartate aminotransferase, alanine transaminase, lactate dehydrogenase and DPPH, HRSA assays were analyzed in the gill, muscle, and liver of Mrigal. Protein and lipid levels increased on the 7th,14th day compared to control. Carbohydrate levels decreased on the 7th,14th day of exposure, and the enzymatical changes increased on the 7^th,14th day. Antioxidant levels highly increased in DPPH assay compared to the HRSA assay. This study provides the biochemical, antioxidant, and behavioral changes in relation to the exposure of MgO NPs.

Biotin alleviates hepatic and intestinal inflammation and apoptosis induced by high dietary carbohydrate in juvenile turbot (Scophthalmus maximus L.)

Excessive dietary carbohydrate commonly impairs the functions of liver and intestine in carnivorous fish. In the present study, a 10-week feeding trial was carried out to explore the regulation of biotin on the hepatic and intestinal inflammation and apoptosis in turbot (Scophthalmus maximus L.) fed with high carbohydrate diets. Three isonitrogenous and isolipidic experimental diets were designed as follows: the CC diet with 18.6% of carbohydrate and 0.04 mg/kg of biotin, the HC diet with 26.9% of carbohydrate and 0.05 mg/kg of biotin, and the HCB diet with 26.9% of carbohydrate and 1.62 mg/kg of biotin. Results showed that high dietary carbohydrate (HC diet) impaired the morphology of liver and intestine, however, inclusion of dietary biotin (HCB diet) normalized their morphology. Inflammation-related gene expression of nuclear factor κB p65 (nf-κb p65), tumor necrosis factor α (tnf-α), interleukin-1β (il-1β), il-6 and il-8, and the protein expression of NF-κB p65 in the liver and intestine were significantly up-regulated in the HC group compared to those in the CC group (P < 0.05), the HCB diet decreased their expression compared to the HC group (P < 0.05). The gene expression of il-10 and transforming growth factor-β (tgf-β) in the liver and intestine were significantly decreased in the HC group compared to the CC group (P < 0.05), and inclusion of dietary biotin increased the il-10 and tgf-β expression in the liver and intestine (P < 0.05). Moreover, compared to the CC group, the HC group had a stronger degree of DNA fragmentation and more TUNEL-positive cells in the liver and intestine, and the HCB group had a slighter degree of DNA fragmentation and fewer TUNEL-positive cells compared to the HC group. Meanwhile, the gene expression of B-cell lymphoma protein-2-associated X protein (bax) and executor apoptosis-related cysteine peptidase 3 (caspase-3) were significantly up-regulated and the gene expression of B-cell lymphoma-2 (bcl-2) was significantly down-regulated both in the liver and intestine in the HC group compared with those in the CC group (P < 0.05). Inclusion of dietary biotin significantly decreased the bax and caspase-3 mRNA levels and increased bcl-2 mRNA level in the liver and intestine (P < 0.05). In conclusion, high dietary carbohydrate (26.9% vs 18.6%) induced inflammation and apoptosis in liver and intestine. Supplementation of biotin (1.62 mg/kg vs 0.05 mg/kg) in diet can alleviate the high-dietary-carbohydrate-induced hepatic and intestinal inflammation as well as inhibit apoptosis in turbot. The present study provides basic data for the application of biotin into feed, especially the high-carbohydrate feed for turbot.

Risk assessment of glyphosate and malathion pollution and their potential impact on Oreochromis niloticus: role of organic selenium supplementation

A field survey was conducted on five fish farms to trace glyphosate and malathion pollution with some physicochemical parameters. A precise half-life time, LC50-96h, of these agrochemicals on Oreochromis niloticus, as well as chronic exposure with organic selenium (OS) supplementation, were experimentally investigated. Oreochromis niloticus was subjected to the following: (negative control); (2 mg L-1 glyphosate); (0.5 mg L-1 malathion); (glyphosate 1.6 mg L-1 and 0.3 mg L-1 malathion); (glyphosate 2 mg L-1 and OS 0.8 g kg-1 diet); (malathion 0.5 mg L-1 and OS 0.8 g kg-1 diet) and (glyphosate 1.6 mg L-1; malathion 0.3 mg L-1 and OS 0.8 g kg-1 diet). Furthermore, data from the analyzed pond revealed a medium risk quotient (RQ) for both agrochemicals. The detected agrochemicals were related to their application, and vegetation type surrounding the farms, also their biodegradation was correlated to water pH, temperature, and salinity. Glyphosate and malathion had half-lives of 2.8 and 2.3 days and LC50-96h of 2.331 and 0.738 mg L-1, respectively. The severest nervous symptoms; increased oxidative stress markers, as well as high bacterial count in the livers and kidneys of fish challenged with Aeromonas hydrophila, were observed in the combined exposure, followed by a single exposure to malathion and then glyphosate. Organic selenium mitigated these impacts.

Primary stress response and biochemical profile of Labeo rohita (Hamilton, 1822) experimentally parasitized with Argulus bengalensis (Ramakrishna, 1951)

Argulosis is a major problem that causes huge economic loss in aquaculture. In a microcosm, an infested condition was developed upon Labeo rohita with 100 ± 10 adult morphs of Argulus bengalensis per fish. Primary stress response and biochemical profiles of the host were evaluated to underscore the pathogenicity of the parasites. Significant alterations in biochemical parameters were monitored at four different post-infestation time points: days 1, 3, 6 and 9. The overall increasing trends of both plasma cortisol and plasma epinephrine indicate parasite-induced primary stress response among experimental fish. The study revealed a hyperglycaemic trend throughout the infestation period, which has been correlated with hypoxia-associated glycogenolysis. Decreasing level of plasma cholesterol has also been correlated with the development of anaemia and subsequent hypoxia among the infested fish. Plasma protein of the experimental fish initially increases as an outcome of the immediate innate immune response against Argulus infestation, whereas the decrease in plasma protein at the later period of infestation results from less-dietary protein intake due to loss of appetite, reduced digestibility and metabolic proteolysis. Plasma Na⁺ concentration showed an overall decreasing trend throughout the infestation period, which may be due to excess production of catecholamine under stress. Nonetheless, plasma K⁺ concentration showed an increasing trend up to day 6 of infestation, and thereafter the value declined to the control level. Plasma ionic imbalances reflect changes in cell permeability under tissue hypoxia and the wounds produced on the skin for intensive feeding activity of the parasites. Both serum glutamate oxaloacetate transaminase and serum glutamate pyruvate transaminase activities were significantly elevated throughout the infestation period, which indicates excess synthesis or release of those enzymes from the damaged cells of the tissues. Activities of some renal, hepatic and branchial antioxidant enzymes, viz., superoxide dismutase, catalase and glutathione-S-transferase, increased in the infested fish. The fact is explained as an effort of the fish for gaining adaptive adjustment to neutralize the oxidative stress generated under the parasitic stress. The overall experimental result points towards the generation of potential stress upon host fish by this branchiuran parasite. The biochemical alterations of the fish under argulosis are centred around the two stress-sensitive hormones, cortisol and epinephrine. The outcome of the study will be the important physiological determinants in adopting a suitable control measure as well as assessing the nutritional value of the fish under diseased condition.

In vitro and in vivo efficacy of methyl oleate and palmitic acid against ESBL producing MDR Escherichia coli and Klebsiella pneumoniae

PURPOSE

Antibiotic resistance is a huge problem that stays to challenge the healthcare sector in a large part of the world in both developing and developed countries. The spread of multi drug resistant (MDR) bacteria in hospital and community settings remains a widely uncertain problem and a heavy burden to health services.

METHODS

This study unveils the in vitro and in vivo anti-ESBL potential of Methyl oleate (MO) and Palmitic acid (PA) against ESBL producing MDR bacterial pathogens such as Escherichia coli and Klebsiella pneumoniae. Microscopic observations unveiled the anti-ESBL efficacy of test compounds. MTT assay, in vivo anti-infective efficiency of MO and PA was tested with different concentrations.

RESULTS

The pure compounds of MO and PA from Oxynema thaianum demonstrated high inhibitory activity in MIC and MBC assays against MDR E. coli and K. pneumoniae. Moreover, the anti-ESBL potential of MO and PA was validated through light, confocal laser scanning and scanning electron microscopic analyses. The IC₅₀ values of MO and PA against A549 cells was recorded as 625 μg mL^-1 and 514 μg mL^-1, respectively. In Artemia nauplii cytotoxicity assay, the LC₅₀ value of MO and PA were recorded as 53.33 μg mL^-1 and 50 μg mL^-1 respectively. The 96 h lethal concentrations obtained for Lobeo rohita treated with different concentrations of Methyl oleate and Palmitic acid. The LC₅₀ for MO and PA was 50 mg L^-1 and 100 mg L^-1, respectively.

CONCLUSION

Therefore the study concluded that the promising effects of MO and PA can be used as an alternative biological agent which could be positively explored to treat ESBL producing MDR pathogens.

Acrylamide-induced hematotoxicity, oxidative stress, and DNA damage in liver, kidney, and brain of catfish (Clarias gariepinus)

This study was carried out to explore the possible deleterious impacts of acrylamide (ACR) on catfish (Clarias gariepinus). The estimation of mortalities, the examination of the clinical picture, the evaluation of blood parameters, oxidative stress, DNA damage, and the histopathological picture were performed in the liver, kidney, and brain samples of the experimentally ACR-exposed catfish. The 96 hours LC₅₀ value was estimated to be 133 mg/L by the hydrostatic method. Fish were reared in water containing four different concentrations of ACR as follows: 20%, 40%, 60%, and 80% of the estimated LC₅₀ for 2 weeks. Abnormal behavioral, clinical, and postmortem responses were depicted. The anemic response including significant decreases in red blood cells, hemoglobin, and packed cell volume following the ascending concentrations of ACR were recorded. The malondialdehyde was significantly increased, whereas reduced glutathione level, superoxide dismutase, and total antioxidant capacity were significantly decreased. The DNA fragmentation assay illustrated a clear laddering pattern in all the tested organs. Notably, the brain was the most influenced organ. It is presumed that ACR contamination showed adverse impacts on the catfish.

Impact of untreated and Sargassum wightii-treated brilliant green dye exposure on Indian major carp, Labeo rohita Ham.: hematology, biochemistry, enzymology and histopathology

Water pollution due to agricultural and industrial processes may cause adverse biological effects in aquatic organisms such as fishes. The removal of brilliant green (BG) dye from aqueous solution using seaweed Sargassum wightii was carried out. Further, it aimed to evaluate the exposure of BG dye activity on hematological, plasma biochemical, enzymological activities and histopathology of Indian major carp, Labeo rohita as a biomarker. High mortality rate (T2 65%) in the fishes exposed to untreated BG dye shows the toxic nature of the dye. Whereas fishes grown in treated BG dye showed less mortality rate (T3 25%) and (T1 30%) which depicts the less toxicity. The observed behavioral, biochemical, hematological and enzymological parameters were showed a significant increase in the treated BG dye. Extensive histopathological lesions in gill, liver and kidney tissues were observed in untreated BG dye compared to fishes grown in S. wightii-treated BG dye might be due to the stress caused by the toxic presence in the dye. The results concluded that S. wightii-treated BG dye does not have any inhibitory effect which reveals the nontoxic nature.

Chronic amoxicillin exposure affects Labeo rohita: assessment of hematological, ionic compounds, biochemical, and enzymological activities

Labeo rohita were exposed to amoxicillin at a concentration of 1 mg/L (Treatment -I) and 0.5 mg/L (Treatment-II) for a period of 35 days. Numerous alterations were found in amoxicillin treatment groups when compared to the control group. Hemoglobin (Hb), hematocrit (Hct), and erythrocytes (RBCs) levels were significantly (P < 0.05) decreased. Leukocytes (WBC), mean cell volume (MCV), mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC) levels were significantly (P < 0.05) increased. In the plasma and gill tissues, ionic compounds (sodium, potassium, and chloride) levels were significantly declined throughout the treatment period. The plasma biochemical profiles were significantly altered: glucose level remained low (except at the end of 7th day in Treatment -I) till 35 days of the treatment period. Biphasic trend occurred in the protein level, significant increase was observed on 7th and 28th day (Treatment -I and -II), and 35th day (Treatment -I), and in remaining days its level was found to be decreased. Glutamate oxaloacetate transaminase (GOT) activity in the plasma was inhibited significantly, whereas in the gill, liver, and kidney tissues the enzyme activity was elevated. Plasma glutamate pyruvate transaminase (GPT) activity was inhibited throughout the study period. GPT activity in the gill was found to be elevated during the treatment period. Liver GPT activity was elevated in all the treatments except 28th (Treatment-I) and 35th day (Treatment-I, and II). GPT activity in the kidney was elevated (except 14th day in Treatment-II). Lactate dehydrogenase (LDH) activity was inhibited in plasma (except 14th day in Treatment-II), gill, liver (except 7th day in Treatment-I), and kidney tissues significantly (P < 0.05). The present study emphasizes that amoxicillin at 1 and 0.5 mg/L concentrations affects the hematological/biochemical/electrolytes/enzymological parameters of fish and these biomarkers serve as an effective test system for environmental risk assessment of pharmaceuticals in the aquatic environment.

Responses of Labeo rohita fingerlings to N-acetyl-p-aminophenol toxicity

The short term (96 h) toxicity of N-acetyl-p-aminophenol (0.58 mg/L - Treatment I and 0.29 mg/L - Treatment II) on certain health indicators (haematology, biochemical, and enzymology) of an Indian major carp Labeo rohita was studied. When compared to control, N-acetyl-p-aminophenol treated fish showed a significant (P < 0.05) decrease in haemoglobin (Hb), haematocrit (Hct), and erythrocyte (RBC) levels throughout the study period. Whereas, a significant (P < 0.05) increase were noted in leucocyte (WBC) counts (except 48 h in Treatment-I), mean corpuscular volume (MCV), and mean corpuscular haemoglobin (MCH) values (except 24 h in Treatment-I). Mean corpuscular haemoglobin concentration (MCHC) values were found to be decreased significantly (P < 0.05) in fish exposed to 0.58 mg/L of N-acetyl-p-aminophenol, whereas in 0.29 mg/L exposed fish the values were found to be increased significantly (P < 0.05) (except 72 h). A significant (P < 0.05) increase in plasma glucose levels was noticed in fish exposed to 0.58 mg/L of N-acetyl-p-aminophenol (except 96 h). However, a biphasic trend in plasma glucose level was observed at 0.29 mg/L of N-acetyl-p-aminophenol exposed fish. Protein levels were found to be increased in both the treatments except at the end of 48 and 96 h in 0.58 and 0.29 mg/L, respectively. In both the treatments fluctuations of enzyme (GOT, GPT, and LDH) activities in gill and liver were also noted. However, these enzyme activities found to be significantly (P < 0.05) decreased in kidney and plasma of fish. From the result we conclude that the drug N-acetyl-p-aminophenol upon short term exposure could pose a risk to fish and the alteration of these parameters can be used to ecological risk assessment of pharmaceuticals in aquatic organisms.

Hematological, hepatic enzymes' activity and oxidative stress responses of gray mullet (Mugil cephalus) after sub-acute exposure to copper oxide

Given the importance of assessing potential toxicity of heavy metals in valuable species of aquatic animals, the goal of the present research was to assess the sub-acute effects of copper oxide on hematological, enzymological, and oxidative stress responses of gray mullet to measure toxicity of copper oxide pollution in this significant fish. The median lethal concentration (LC₅₀) value of copper oxide to gray mullet was detected at 3.15 ± 0.039 mg/L for 96 h, and 25 and 50% of the 96-h LC₅₀ values were selected as sub-acute concentrations. The fish were exposed to (0.79 and 1.57 mg/L) copper oxide for 21 days. At the end of 21 days, the results showed that hemoglobin (Hb), hematocrit (Hct), red blood cells (RBC) count, MCV, MCH, and MCHC levels were found to be decreased in copper oxide treated fish, whereas white blood cells (WBC) count increased in copper-treated fish. Plasma aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH) activity increased in treated groups; however, copper oxide in both groups of sub-acute exposure significantly decreased plasma alkaline phosphatase (ALP) activity compared to the control group. Superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH) levels significantly declined in copper oxide-treated fish. These findings indicated the deleterious effects of copper oxide on gray mullet, even at low concentrations, and offered that hematological and hepatic enzyme activity and antioxidants are suitable tools for evaluating heavy metals toxicity.

Evaluation of acute and sublethal effects of chloroquine (C18H26CIN3) on certain enzymological and histopathological biomarker responses of a freshwater fish Cyprinus carpio

•

Chloroquine (CQ) toxicity on fresh water fingerlings Cyprinus carpio was studied.

•

Median lethal concentration (96 h) was noted.

•

Acute (96 h) and sub-lethal (35 days) treatments was performed.

•

Enzymological activity and histological alteration was analysed.

•

Drug CQ has a toxic effect on non-target organism.

In this study the toxicity of antimalarial drug chloroquine (CQ) on certain enzymological (GOT, GPT and LDH) and histopathological alterations (Gill, liver and kidney) of a freshwater fish Cyprinus carpio was studied after acute (96 h) and sublethal (35 days) exposure. The median lethal concentration (96 h) of CQ was 31.62 mg/ml. During acute treatment (CQ at 31.62 mg/ml) the treated fish groups showed a significant increase in GOT and GPT activities in blood plasma; whereas LDH activity was decreased when compare to control groups. To analyse the effects of drug at the lowest concentration, the fish were exposed to 3.16 mg/ml (1/10th of 96 h LC50 value) for 96 h. In sublethal treatment (3.16 mg/ml) GOT activity increased up to 14th day and decreased during the rest of the exposure period (21, 28 and 35th day). A biphasic response in GPT activity was observed. LDH activity was found to be increased throughout the study period (35 days) compare to control groups. The alterations in enzyme activities in blood plasma were found to be significant at p < 0.05 (DMRT). Many histopathological changes in vital organs such as gill, liver and kidney of fish were observed in CQ treated group (acute and sub-lethal) compare to normal group. The alterations in the enzymological and histopathological study in the present investigation indicate that the drug CQ has toxic effects on non-target organisms. We conclude that the alterations in enzymological parameters and histopathological changes can be used as biomarker to assess the health of the aquatic organism/environment. Further data on molecular studies are needed to define the mode of action and toxicity of these emerging pollutants.

Potential effects of low molecular weight phthalate esters (C16H22O4 and C12H14O4) on the freshwater fish Cyprinus carpio

The aim of the present study is to assess the toxic effect of dibutyl phthalate (DBP) and diethyl phthalate (DEP) on the freshwater fish Cyprinus carpio. The median lethal concentrations of DBP and DEP for 96 h are found to be 35 and 53 mg L-1, respectively. Fish were exposed to 3.5 mg L-1 (Treatment I) and 1.75 mg L-1 (Treatment II) of DBP and 5.3 mg L-1 (Treatment I) and 2.65 mg L-1 (Treatment II) of DEP for a period of 35 days. The DBP and DEP exposed fish show a concentration based toxic effect on the selected parameters of this study. The hematological parameters, such as hemoglobin (Hb), hematocrit (Hct) and erythrocyte (RBC), were found to decrease in the DBP and DEP treated fish, whereas their leucocyte (WBC) count increased compared to that of the control groups. A biphasic response is noted in the erythrocyte indices, such as mean cellular volume (MCV), mean cellular hemoglobin (MCH) and mean cellular hemoglobin concentration (MCHC), throughout the study period. Exposure to DBP and DEP caused a significant (p < 0.05) decrease in sodium (Na+), potassium (K+), and chloride (Cl-) levels in the gill and brain of the fish throughout the study period when compared to that of their respective controls. The plasma protein level decreased in all the treatments, whereas the plasma glucose level significantly increased in the DBP and DEP exposed fish. Maximum inhibition of Na+/K+-ATPase activity was noticed in the gill and brain of the fish exposed to DBP and DEP. The cholinesterase (ChE) activity in the brain of the fish significantly decreased throughout the study period. A significant (p < 0.05) increase in glutamate oxaloacetate transaminase (GOT) and glutamic pyruvate transaminase (GPT) activity was noted in the fish exposed to both toxicants. The antioxidant enzymatic parameters such as superoxide dismutase (SOD) and catalase (CAT) activities were found to decrease in the gill and liver of the DBP and DEP treated fish, whereas a significant (p < 0.05) increase in lipid peroxidation (LPO) was observed. The above mentioned parameters could be used as potential biomarkers in clinical trials for the assessment of plasticizers. This study provides indispensable information towards future research on the effect of plasticizers on non-target organisms including humans.

Deficient and excess dietary selenium levels affect growth performance, blood cells apoptosis and liver HSP70 expression in juvenile yellow catfish Pelteobagrus fulvidraco

We investigated the effects of deficient and excess dietary selenium (Se) on growth, blood cells apoptosis and liver heat shock protein 70 (HSP70) expression in juvenile yellow catfish (Pelteobagrus fulvidraco). After 8 weeks, yellow catfish (initial weight: 2.12 ± 0.01 g) fed isonitrogenous and isolipid diets containing <0.05 (deficient dietary Se) or 6.5 (excess dietary Se) mg Se/kg displayed a significantly lower weight gain ratio (WGR) than those fed a diet containing 0.23 (normal dietary Se) mg Se/kg. As dietary Se levels increased, liver Se concentration, glutathione peroxidase activity and the hepatosomatic index increased significantly. Plasma glucose concentration was highest in the normal treatment compared with the excess dietary Se treatment. Both deficient and excess dietary Se lead to increased reactive oxygen species (ROS) production and apoptosis ratio in blood cells, whereas only excess dietary Se increased their cytoplasmic free-Ca(2+) (CF-Ca(2+)) concentration. Excess dietary Se also resulted in the highest level of HSP70 expression, thereby possibly providing a protective mechanism against oxidative stress. These results indicate that both deficient and excess dietary Se restrained the growth of juvenile yellow catfish and caused oxidative stress. The overproduction of ROS may act as a signal molecule mediate apoptosis when dietary Se deficiency. Both ROS and CF-Ca(2+) were recorded when dietary Se excess, suggesting that Ca(2+) may be activated by Se and play a major role during Se-induced oxidative stress and cell apoptosis.