Toxicological effects of meloxicam on physiological and antioxidant status of common carp (Cyprinus carpio).

BACKGROUND: Fish in aquatic environments are end consumers of the food chain and are widely used for the evolution effects of environmental pollution and their interactions in aquatic ecosystem. OBJECTIVE: In the present study, common carp (Cyprinus carpio) fingerlings were selected to assess the potential risk and aquatic toxicity of meloxicam as a non-steroidal anti-inflammatory and a commonly used pharmaceutical drug. METHODS: In order to evaluate meloxicam toxicological effect on haematological, antioxidant status, enzymological and histological parameters, based on its LC50 24 h acute toxicity (10.05 mg L-1 ), fish fingerlings were exposed to four doses of meloxicam including; 0 (control), 0.1 (low), 1 (medium) and 2 mg L-1 (high) under static bioassay method for 28 days. RESULTS: The results showed that sublethal doses of meloxicam significantly decreased alanine aminotransferase, alkaline phosphatase, superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) levels in comparison with the control group after 28 days (p < 0.05). However, red blood cell, haematocrit, haemoglobin and malondialdehyde values in fish exposed to meloxicam significantly increased alongside its concentration (p < 0.05) more than the control group after 28 days. SOD, CAT and GPX mRNA expression levels in gill, liver, kidney and brain organ of fish under meloxicam treatment were significantly down-regulated compared to the control group (p < 0.05). Histopathological assessment showed the increased vacuolation in hepatocytes in liver of fish exposure to medium and high doses of meloxicam. CONCLUSION: In conclusion, meloxicam induces oxidative stress in common carp which results a disruption of physiological and health status of this species based on our current findings.

Modulatory effect of dietary copper nanoparticles and vitamin C supplementations on growth performance, hematological and immune parameters, oxidative status, histology, and disease resistance against Yersinia ruckeri in rainbow trout (Oncorhynchus mykiss).

Copper and vitamin C are micronutrients needed for the living organism's functions. Vitamin C has a great effect on the immune system of fish. The present study aimed to evaluate the effects of dietary copper nanoparticles (Cu-NPs) and vitamin C (VC) supplementations on rainbow trout (Oncorhynchus mykiss) juveniles. So, 216 rainbow trout juveniles were randomly assigned to six groups with trial diets supplemented with Cu-NPs and VC including 0/0 (T1, control diet), 0/250 (T2), 0/500 (T3), 2/250 (T4), 2/500 (T5), and 2/0 (T6) mg Cu-NPs/VC per kg diet. After the feeding trial for 60 days, the fish were challenged with Yersinia ruckeri, and the survival rate was calculated for 15 days. Based on the data analysis, weight gain (WG), specific growth rate (SGR), protein efficiency ratio (PER), lysozyme, alternative complement activity (ACH50), hematocrit (Hct), hemoglobin (Hb), and mean corpuscular volume (MCV) were significantly (p < 0.05) increased in the fish fed on T4 and T5 diets compared with the control group. Catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPX) were significantly (p < 0.05) decreased in the fish fed with diets contain Cu-NPs and VC (T4 and T5). The expressions of TNF-α, IL-1ß, IL-10, SOD, CAT, and GPX genes were significantly (p < 0.05) decreased in the fish fed on T3, T4, and T5 diets versus the control. In addition, the dietary Cu-NPs and VC supplementations significantly enhanced resistance against pathogens and led to the control of infection in rainbow trout. In conclusion, Cu-NPs and VC administered as feed additives at 2/250-500 mg/kg elevated the growth performance, antioxidant capacity, and health of rainbow trout.

Fluctuation of biochemical, immunological, and antioxidant biomarkers in the blood of beluga (Huso huso) under effect of dietary ZnO and chitosan-ZnO NPs.

The objective of the present study was to investigate the effects of dietary supplementation with zinc oxide (ZnO) and chitosan-zinc nanoparticles (chitosan-ZnO NPs) on biochemical, immunological, and antioxidant biomarkers in blood of juvenile belugas (Huso huso). The beluga juveniles with initial weight of 287 ± 46 g were fed with eight experimental diets containing 0 g kg-1 ZnO (the control diet); 10, 20, and 40 mg kg-1 ZnO; and 10, 20, and 40 mg kg-1 chitosan-ZnO NPs and 36 mg kg-1 chitosan. After 28 days of culture, the fish were fed with ZnO and chitosan-ZnO NP-supplemented diets showed a more significant increase in total antioxidant capacity (TAC), superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), glutathione peroxidase (GPX), and glutathione S-transferase (GST) activity (p < 0.05) compared to the control group. There were no significant differences (p > 0.05) in malondialdehyde (MDA) and glucose level in all treatment groups. The results showed that with increasing levels of ZnO and chitosan-ZnO NPs, alternative complement activity (ACH50), and total immunoglobulin, total protein, albumin, and lysozyme had a significant increase in fish fed with ZnO and chitosan-ZnO NP-supplemented diets compared to the control group (p < 0.05). ALP, ALT, and AST enzyme activities showed significant difference between control and treatment groups (p > 0.05), while the levels of LDH enzyme activity, urea, and creatinine decreased by increasing both ZnO and chitosan-ZnO NP levels. These results demonstrated that dietary chitosan-ZnO NPs could improve the health status, immune function, and antioxidant capacity of the cultured beluga juvenile.

Effects of dietary onion (Allium cepa) powder on growth, innate immune response and hemato-biochemical parameters of beluga (Huso huso Linnaeus, 1754) juvenile.

The present study was aimed at determining the effects of dietary onion powder on growth, innate immune response and hemato-biochemical parameters of beluga juvenile (Huso huso). Basal diets containing onion powder 0 (control), 0.5 and 1% of feed were fed to beluga juvenile. At the end of the experiment, the highest weight gain (WG%) and specific growth rate (SGR) was observed in group fed with 1% onion (P < 0.05). There were no significant difference (P > 0.05) about feed conversion ratio (FCR) in treatment groups that fed diets containing various levels of onion powder. After 8 weeks, serum lysozyme activity, superoxide dismutase activity (SOD), respiratory burst activity and serum total immunoglobulin (Ig) showed a significant increase in treatment group with 1% onion powder compared to other groups (P < 0.05). The group fed 1% onion showed a significantly increases in the number of erythrocytes (RBC), leucocyte (WBC), haematocrit (Hct) levels compared to the control group (P < 0.05). Haemoglobin, monocyte, lymphocyte and neutrophil had no significant change (P > 0.05) in treatment groups and control. The analysis of AST and LDH levels showed a significant decrease in 1% onion compared to the control and 0.5% onion diet (P < 0.05), while ALT and ALP levels were not influenced (P > 0.05). The blood glucose, total protein, triglyceride, cholesterol, albumin and globulin levels were lower in treated groups compared with the control (P < 0.05). The results of this study demonstrated that dietary onion powder could be an improvement in growth, hematological parameters and immune function of beluga juvenile.

Changes in metabolic enzymes, cortisol and glucose concentrations of Beluga (Huso huso) exposed to dietary methylmercury.

In this paper, effects of dietary methylmercury (MeHg) on several blood biochemical parameters including GLU (glucose), LDH (lactate dehydrogenase), AST (aspartate aminotransferase), ALT (alanine aminotransferase), ALP (alkaline phosphatase) and cortisol were investigated in the Beluga sturgeon (Huso huso). Beluga juveniles were fed for 32 days on four diets containing MeHg (control: 0.04 mg kg⁻¹; low: 0.76 mg kg⁻¹; medium: 7.88 mg kg⁻¹; and high 16.22 mg kg⁻¹ treatment). Significant increases (P < 0.05) were observed in all biochemical parameters, except ALP levels, which decreased significantly (P < 0.05) compared to the control group with either dose- or time-dependent effects. These results suggest that long-term dietary MeHg exposure may affect metabolic enzyme activity and glucose levels in Belugas. These findings provide useful information for environmental and fishery officials to apply in future decisions for managing fish resources in Caspian Sea.

Molecular cloning of cDNA of mammalian and chicken II gonadotropin-releasing hormones (mGnRHs and cGnRH-II) in the beluga (Huso huso) and the disruptive effect of methylmercury on gene expression.

Two gonadotropin-releasing hormone (GnRH) isoforms were identified in the beluga (Huso huso) brain by cDNA sequencing: prepro-mammalian GnRH (mGnRH) and prepro-chicken GnRH-II (cGnRH-II). The nucleotide sequences of the beluga mGnRH and cGnRH-II precursors are 273 and 258 base pairs (bp) long, encoding peptides of 91 and 86 amino acids, respectively. To investigate the effect of methylmercury (MeHg) on GnRH gene expression, animals were fed with four diets containing increasing levels of MeHg (0 mg kg(-1) [control]; 0.76 mg kg(-1) [low]; 7.8 mg kg(-1) [medium]; 16.22 mg kg(-1) [high]) for 32 days. The effects of MeHg on brain GnRH mRNA levels were evaluated by real-time PCR. A significant decrease in brain mGnRH and cGnRH-II mRNA levels were detected in fish receiving high dietary MeHg dose compared to controls on day 11 (P < 0.05). On day 18 and 32, all treatment groups had significantly lower brain mGnRH and cGnRH-II mRNA levels compared to the control group (P < 0.05). These findings demonstrate a disruptive role of MeHg on the level of brain mGnRH and cGnRH-II mRNAs in immature beluga.

Proteome modifications of juvenile beluga (Huso huso) brain as an effect of dietary methylmercury.

Methylmercury (MeHg) is the most toxic form of mercury which is bioaccumulated in the aquatic food chain. It has been shown that one of the main targets of MeHg toxicity is the brain, but there is little knowledge of the molecular mechanisms of its toxic effects. In this work we used a proteomics analysis to determine the changes in the brain proteome of juvenile beluga (Huso huso) exposed to dietary MeHg. The juvenile beluga were fed the diet containing 0.8 ppm MeHg for 70 days. Proteins of the brain tissue were analyzed using two-dimensional electrophoresis and MALDI-TOF/TOF mass spectrometry. We found eight proteins with significant altered expression level in the fish brain exposed to MeHg. These proteins are involved in different cell functions including cell metabolism, protein folding, cell division, and signal transduction. Our results support the idea that MeHg exerts its toxicity through oxidative stress induction and apoptotic effects. They also suggest that chronic MeHg exposure would induce an important metabolic deficiency in the brain. These findings provide basic information to understand possible mechanisms of MeHg toxicity in aquatic ecosystems.