Juvenile Common Carp Research Articles

Accumulation of Metals in Juvenile Carp (Cyprinus carpio) Exposed to Sublethal Levels of Iron and Manganese: Survival, Body Weight and Tissue.

Many oxbows are contaminated by Fe and Mn as a consequence of the elemental concentration of sediment and water originating from the Upper Tisza Region of Hungary. The phenomenon is partly caused by anthropogenic activities and mainly due to the geochemical characteristics of the region. The effects of Fe and Mn on the aquatic ecosystem of these wetlands were investigated in a model experiments in this study. Survival, individual body weight and the elemental concentrations of organs were determined in common carp (Cyprinus carpio) juveniles reared in Fe and Mn contaminated media (treatment 1: Fe 0.57mgL-1, Mn 0.29mgL-1, treatment 2: Fe 0.57mgL-1, Mn 0.625mgL-1, treatment 3: Fe 1.50mgL-1, Mn 0.29mgL-1, treatment 4: Fe 1.50mgL-1, Mn 0.625mgL-1 and control: Fe 0.005mgL-1, Mn 0.003mgL-1), for rearing time of 49days. The treatment with Fe and Mn did not have any effect on the survival data and individual body weight in the levels tested. The highest concentration of Fe and Mn was found in the liver and brain of carp juveniles, while the lowest concentration of these elements occurred in the muscular tissue and gills. The treatment where Fe and Mn were applied in the highest concentrations resulted in a statistically higher level of these elements in the brain, grills and muscle tissues. The treatment where only Mn was present in the highest concentration caused increased level of Mn only in the liver. We found metal accumulation in almost every organ; however, the applied concentrations and exposure time did not affect the survival and average body weight of carp juveniles.

Alteration of parameters of energy metabolism and ATPase enzymatic system in juvenile common carp (Cyprinus carpio) chronically exposed to tributyltin

The effect of long-term exposure to tributyltin (TBT) on energy metabolism and adenosine triphosphatase (ATPase) enzymatic system in freshwater teleost was investigated. The impact on the parameters of energy metabolism (the content of glucose (Glu) and lactate (LA), and the activities of hexokinase (HK), pyruvate kinase (PK), and lactate dehydrogenase(LDH)) in the muscle tissue, as well as on the ATP enzymatic system (ATP content, Total-ATPase, Na+-K+-ATPase, and Ca2+-Mg2+-ATPase) in the gill tissue of common carp was evaluated. Fish were exposed to sublethal concentrations of TBT (75, 0.75, and 7.5 µg/l) for 60 days. Based on the results, long-term exposure to TBT could lead to obvious ATP enzymatic system responses, including the decreased ATP content and Na+-K+-ATPase activity, and the increased activities of Total-ATPase and Ca2+-Mg2+-ATPase. Moreover, the parameters of energy metabolism in muscle were also regulated, such as induced indices of the levels of Glu and LA, and the activities of HK and PK, and inhibited indices of LDH activity. Shortly, the measured physiological responses in fish could provide useful information to better understand the mechanisms of TBT-induced bio-toxicity, and could be used as potential biomarkers for monitoring the TBT pollution in the field.

Food and Feeding Habits of Common Carp (Cyprinus carpio) Larvae and Juveniles in Earthen Ponds

Food and Feeding Habits of Common Carp (Cyprinus carpio) Larvae and Juveniles in Earthen Ponds

Acclimation temperature alters the relationship between growth and swimming performance among juvenile common carp (Cyprinus carpio)

Individual variation in growth, metabolism and swimming performance, their possible interrelationships, and the effects of temperature were investigated in 30 juvenile common carp (Cyprinus carpio) at two acclimation temperatures (15 and 25°C). We measured body mass, critical swimming speed (Ucrit), resting metabolic rate (RMR), active metabolic rate (AMR) and metabolic scope (MS) twice (28days apart) in both temperature groups. Fish acclimated to 25°C showed a 204% higher specific growth rate (SGR) than those acclimated to 15°C due to a 97% higher feeding rate (FR) and a 46% higher feed efficiency (FE). Among individuals, SGR was positively correlated with the FR and FE at both low and high temperatures. All measured variables (Ucrit, RMR and AMR) related to swimming except MS showed a high repeatability after adjusting for body mass (mass-independent). Fish acclimated to 25°C had a 40% higher Ucrit compared with 15°C acclimated fish, which was at least partially due to an improved metabolic capacity. AMR showed a 97% increase, and MS showed a 104% parallel increase with the higher acclimation temperature. Residual (mass-independent) Ucrit was positively correlated with residual RMR, AMR and MS, except for the residual RMR at high temperature. When acclimated to the lower temperature, both the residual and absolute Ucrit were negatively correlated with FR and FE and, hence, with SGR, suggesting a functional trade-off between growth and locomotion in fish acclimated to low temperatures. However, when acclimated to the higher temperature, this trade-off no longer existed; absolute Ucrit was positively correlated with SGR because individuals with rapid growth exhibited greatly increased body mass. The higher metabolic capacity at 25°C showed a positive effect on both swimming performance and growth rate (because of improved digestive efficiency) under the high-temperature condition, which we did not anticipate. Overall, these results indicate that temperature alters the relationship between growth and swimming performance of juvenile common carp. This change may be an adaptive strategy to seasonal temperature variation during their life history.

Prioritization of contaminated watercourses using an integrated biomarker approach in caged carp

Because of the ever increasing complexity of environmental contamination profiles, there are limitations to the use of analytical pollutant measurements for monitoring and prioritization of watercourses. The potential of biomarkers has been debated for many years, especially in laboratory settings, but there is a need for studies evaluating these approaches in the field. We evaluated the usefulness of a selection of biomarkers, mostly indicators of general physiological status and common stress responses such as oxidative stress, to discriminate among environmental pollution profiles, with the aim of prioritizing contaminated watercourses for targeted remediation efforts. To this end, juvenile common carp (Cyprinus carpio Lin.) were exposed in cages in the field to Flemish watercourses with varying pollution profiles. After six weeks of exposure, the bioaccumulation of key pollutants was measured, and a set of organismal, biochemical and transcriptional endpoints was determined in several tissue types. After data integration a discrete set of 14 parameters was identified, that could successfully distinguish all watercourses from each other. We show that an integrated biomarker approach, mainly targeting common stress responses, can offer the resolving power to discriminate among environmentally relevant exposure scenarios, and a means to prioritize watercourses for targeted remediation.

Oxidative stress and immune disturbance after long-term exposure to bisphenol A in juvenile common carp (Cyprinus carpio)

Bisphenol A (BPA) is a well-known endocrine disrupting chemical (EDC), ubiquitous in the aquatic environment, which poses an ecotoxicological risk to the health of aquatic organisms. However, the immunotoxic effects of its long-term exposure on fish have received limited attention. We examined a number of typical immune-related parameters and oxidative stress indices in the liver and blood serum of the red common carp (Cyprinus carpio), following a 30-day exposure to five different concentrations of BPA (0.1, 1, 10, 100, and 1000μg/L). A significant increase in the hepato somatic index was observed in fish upon exposure to 1000µg/L BPA, which correlated strongly with the accumulated BPA concentrations in fish bile. Induced oxidative stress was also apparent in the exposed fish liver, based on the enhanced levels of lipid peroxidation and inhibited activities of catalase, superoxide dismutase, and glutathione peroxidase. Serum lysozyme and C-reaction protein levels increased at low concentrations of exposure; however, they were significantly suppressed upon exposure to high concentrations. A significant increase was observed in the levels of immunoglobulin M, complement component 3, and alkaline phosphatase, in both fish liver and serum at low doses of 0.1 and 1μg/L. This suggests that long-term exposure to environmentally relevant concentrations of BPA (even as low as 0.1μg/L) could significantly disturb the immune response of fish. Moreover, RXRα expression in the liver was significantly altered upon BPA exposure and the trend underlying this change correlated closely with those of the most immune-related parameters, implying the involvement of the PPARγ/RXRα signaling pathway in regulating the immune response of fish upon long-term BPA exposure. In short, our results demonstrate the susceptibility of fish immune system to long-term BPA exposure. Therefore, the immunotoxicity of EDCs in aquatic organisms should not have been underestimated.

Effect of 4-week feeding of deoxynivalenol- or T-2-toxin-contaminated diet on lipid peroxidation and glutathione redox system in the hepatopancreas of common carp (Cyprinus carpio L.).

The purpose of study was to investigate the effects of T-2 toxin (4.11 mg T-2 toxin and 0.45 mg HT-2 toxin kg(-1) feed) and deoxynivalenol (5.96 and 0.33 mg 15-acetyl deoxynivalenol (DON) kg(-1) feed) in 1-year-old common carp juveniles in a 4-week feeding trial. The exposure of mycotoxins resulted in increased mortality in both groups consuming mycotoxin-contaminated diet. Parameters of lipid peroxidation were not affected during the trial, and antioxidant defence also did not show response to oxidative stress; however, glutatione peroxidase activity slightly, but significantly, decreased in the T-2 toxin group. Glutathione S-transferase activity showed moderate decrease as effect of T-2 toxin, which suggests its effect on xenobiotic transformation. Reduced glutathione concentration showed moderate changes as effect of DON exposure, but T-2 toxin has no effect. Expression of phospholipid hydroperoxide glutathione peroxidase (GPx4) genes showed different response to mycotoxin exposure. T-2 toxin caused dual response in the expression of gpx4a (early and late downregulation and mid-term upregulation), but continuous upregulation was found as effect of deoxynivalenol. Expression of the other gene, gpx4b, was upregulated by both trichothecenes during the whole period. The results suggested that trichothecenes have some effect on free radical formation and antioxidant defence, but the changes depend on the duration of exposure and the dose applied, and in case of glutathione peroxidase, there was no correlation between expression of genes and enzyme activity.

Pathomorphological evaluation of toxic effect of cypermethrin and cyphenothrin in common carp

In this study, juvenile common carp (Cyprinus carpio) were subjected to sublethal concentrations of the synthetic pyrethroids cypermethrin (2 µg/L) and cyphenothrin (5 µg/L) for 75 days. The toxic effects of these substances were analyzed pathomorphologically by conducting necropsies on 7 fish on days 15, 30, 45, 60, and 75. In addition, histopathological examination of the gonads was performed by exposing to 17β-estradiol (E2) (25 µg/L) as a positive control group to assess the endocrine disrupting effects of cypermethrin and cyphenothrin. Hyperemia, telangiectasia, epithelial lifting, and branchitis were observed in the gills of the fish from both treatment groups, and hemorrhage in the kidneys and hyperemia in the brain were also detected. Only 1 fish from each of the cypermethrin and E2 groups was observed to have degeneration of the testicles and edema of the ovary. One fish from the cyphenothrin group had degeneration of the testicles and another had oophoritis of the ovary. Based on the hyperemia and telangiectasia observed in the gills, it was concluded that both cypermethrin and cyphenothrin may lead to shortness of breath in these fish. However, only minor lesions were detected in the gonads; thus, there was no evidence that these synthetic pyrethroids affect the endocrine system

Effects of chronic exposure to tributyltin on tissue-specific cytochrome P450 1 regulation in juvenile common carp

1. The purpose of this study was to compare tributyltin (TBT)-induced cytochrome P450 1 (CYP450 1) regulation in liver, gills and muscle of juvenile common carp (Cyprinus carpio).2. Fish were exposed to sublethal concentrations of TBT (75, 0.75 and 7.5 μg/L) for 60 days. CYP450 1A was measured at the enzyme activity level as 7-ethoxyresorufin-O-deethylase (EROD) activity, as well as the mRNA expression of CYP450 1 family genes (CYP1A, CYP1B, CYP1C1 and CYP1C2) in fish tissues.3. Based on the results, the liver displayed the highest absolute levels of EROD activity, both under nonexposed and exposed conditions. Additional, EROD activities and CYP1A gene levels showed a good correlation in all three organs. According to the mRNA expression of CYP450 1 family genes, it suggested that CYP1A was to accommodate most EROD activity in fish, but other CYP450 forms also involved in this proceeding.4. Overall, the study revealed both similarities and differences in the concentration-dependent CYP450 1 responses of the three target organs, which could provide useful information to better understand the mechanisms of TBT-induced bio-toxicity.

Toxicity of Tributyltin in Juvenile Common Carp (Cyprinus Carpio): Physiological Responses, Hepatic Gene Expression, and Stress Protein Profiling

In this study, the effects of tributyltin (TBT) on biochemical parameters (antioxidant responses and Na(+) -K(+) -ATPase) in different tissues were investigated by using juvenile common carp (Cyprinus Carpio) as well as growth and ion regulation-related genes expression and stress-related proteins profiling in fish liver. Oxidative stress indices and Na(+) -K(+) -ATPase showed tissues-specific responses in fish exposed to different TBT concentrations. All tested genes related to GH/IGF-I axis and ion-regulation were significantly induced in the TBT group with lower concentrations (except for the igfbp3 in 10 μg/L) and were inhibited in 20 μg/L. In addition, the profiling of two proteins Hsp 70 and MT were increasing in a dose-dependent manner under TBT stress. In short, TBT-induced biochemical and molecular responses in different tissues were reflected in the measured parameters in the test. On the basis of TBT residue levels in the natural environment, more long-term experiments at lower concentrations will be necessary in the future.

Alteration of cytochrome P450 1 regulation and HSP 70 level in brain of juvenile common carp (Cyprinus carpio) after chronic exposure to tributyltin.

Tributyltin (TBT), a toxic contaminant in aquatic environments, has bio-accumulated in aquatic food webs throughout the world and can be found at toxic levels in some biota. However, the molecular mechanisms and effects of TBT are not fully understood. The aim of the present study was to investigate the effect of long-term exposure of TBT on cytochrome P450 (CYP450) 1 regulation and heat-shock proteins (HSPs) profiling in brain of freshwater teleost. The effects of long-term exposure to TBT on mRNA expression of cytochrome P450 (CYP450) 1 family genes and ethoxyresorufin O-deethylase (EROD) activity in the brain of common carp were evaluated, as well as HSP 70 level. Fish were exposed to sublethal concentrations of TBT (75 ng/L, 0.75 μg/L and 7.5 μg/L) for 15, 30, and 60 days. Based on the results, long-term exposure (more than 15 days) to TBT could lead to obvious physiological-biochemical responses (based on EROD activity, HSP 70 level and CYP450 1 family genes expression). The mRNA expression of CYP450 1 family genes (CYP1A, CYP1B, CYP1C1 and CYP1C2) suggested that CYP1A was to accommodate most EROD activity in fish, but other CYP450 forms also involved in this proceeding. Thus, the measured physiological responses in fish brain could provide useful information to better understand the mechanisms of TBT-induced bio-toxicity and could be used as potential biomarkers for monitoring the TBT pollution in the field.

Growth, survival and immune responses of juvenile common carp Cyprinus carpio fed with diets enriched with α- tocopheryl acetate

Cyprinus carpio is a popular food fish species and is stocked regularly in reservoirs of Sri Lanka. However in semi-intensive aquaculture, growth and survival of this species are very low resulting in high production cost. The present study was carried out to determine the growth, survival and immune enhancement to pathogenic Aeromonas hydrophyla of juvenile common carp fed with tocopheryl acetate augmented formulated feed. Experimental set up included four treatments each with three replicates arranged in completely randomized design. Initial total weight of the experimental individuals ranged from 200 to 320 g. Experimental fish, which were stocked in 150 cm x 150 cm x 60 cm cement tanks were fed twice a day. The four treatments were; non-enriched commercial feed (T1), non-enriched formulated feed (T2), formulated feed enriched with Tocopheryl Acetate (TA) 2 mg (T3) and formulated ration enriched with TA 4 mg (T4). After the end of the feed trial, experimental animals were exposed to 5 ppm A. hydrophila concentration for 5 minutes duration. The highest Specific Growth Rate (SGR) (1.21) was observed in treatment T4, followed by Control treatment T1 (1.16), which were not significantly different from T3 (1.11). The lowest SGR (1.04) was recorded for T2. The highest (93%) and the lowest (69%) survival were observed in T4 and T3 respectively. The lowest Food Conversion Ratio (FCR) (1.61) was also observed in T4. In T3 and control, they were 1.93 and 1.96 respectively. The highest FCR was also observed in T2 (2.14). No mortality was recorded in T4 after exposing to bacteria concentration while it was 20% in T3. The highest percentage mortality (60%) was recorded from T2 followed by the control (40%). Results indicate that enrichment of prepared feed using Tocopheryl Acetate gives a good growth rate, good survival, hence reducing the production cost. Further, results indicate that Tocopheryl Acetate positively enhances the immunity of the experimental fishes to Aeromonas infection.

Evaluation of the effect of dietary sesamin on white muscle lipid composition of common carp (Cyprinus carpioL.) juveniles

This study was focused on the clarification of the effect of dietary sesamin on fatty acids and the composition of different lipid fractions [phospholipids (PLs), cholesterol and triacylglycerols] in the white muscle of common carp (Cyprinus carpio L.) juveniles. Two different basic diets with defatted fishmeal as a protein source and either only linseed oil or a mixture of linseed and sunflower oil as a lipid source designed to have two different n-3/n-6 ratios (1.21 – CL group; 0.32 – CM group) were produced. Each diet was then used with or without added sesamin (0.58 g 100g−1). One hundred and forty-four individuals were fed in triplicated groups for 63 days until their weight had doubled. No influence of dietary sesamin on growth, mortality or on the white muscle lipid content of the fish was found. Added sesamin significantly decreased the content of PLs and increased the cholesterol content in the CM group. No effect was found in the total lipid fatty acid composition but there was found a significantly lower content of saturated fatty acids and 20:5n-3 in PLs and of 22:6n-3 in triacylglycerols in the sesamin supplemented CL group. These and other differences show either a tendency of lower long chain n-3 fatty acids biosynthesis or their higher use in β-oxidation in sesamin-supplemented groups. We conclude that sesamin in this experiment had no substantial positive impact on the lipid metabolism of juvenile carp.

A Novel Lipase as Aquafeed Additive for Warm-Water Aquaculture.

A novel Acinetobacter lipase gene lipG1was cloned from DNA extracted from intestinal sample of common carp (Cyprinus carpio), and expressed in E. coli BL21. The encoded protein was 406 amino acids in length. Phylogenetic analysis indicated that LipG1 and its relatives comprised a novel group of true lipases produced by Gram-negative bacteria. LipG1 showed maximal activity at 40℃ and pH 8.0 when pNP decanoate (C10) was used as the substrate, and remained high activity between 20℃ and 35℃. Activity of the lipase was promoted by Ca2+ and Mg2+, and inhibited by Zn2+ and Cu2+. Moreover, LipG1 is stable with proteases, most commercial detergents and organic solvents. Substrate specificity test indicated that LipG1can hydrolyse pNP esters with acyl chain length from C2 to C16, with preference for medium-chain pNP esters (C8, C10). Lastly, LipG1was evaluated as an aquafeed additive for juvenile common carp (Cyprinus carpio). Results showed that supplementation of LipG1significantly improved the gut and heptaopancreas lipase activity of fish fed with palm oil diet. Consistently, improved feed conversion ratio and growth performance were recorded in the LipG1 feeding group, to levels comparable to the group of fish fed with soybean oil diet. Collectively, LipG1 exhibited good potential as an aquafeed additive enzyme, and deserves further characterization as the representative of a novel group of lipases.

Biochemical responses over time in common carp Cyprinus carpio (Teleostei, Cyprinidae) during fed supplementation with α-lipoic acid

The current study aimed to evaluate the influence of lipoic acid (LA) supplementation (439.84±6.71mg LA/kg feed) on antioxidants responses throughout the time in intestine, liver and muscle of juvenile common carp Cyprinus carpio. Two experimental groups were fed during four weeks with a diet with or without LA. Glutathione-S-transferase (GST) activity, glutathione (GSH) content, antioxidant capacity against peroxyl radicals (ACAP) and lipid peroxidation (TBARS) were evaluated in these organs. Also, a technique to measure protein disulfide bonds and sulfhydryl groups was optimized for intestine samples. GST activity was significantly higher (p<0.05) in intestine after two weeks of supplementation. GSH content was also significantly higher (p<0.05) in intestine, liver and muscle of fish fed with LA after two and three weeks, respectively. Total capacity antioxidant against peroxyl radicals was significantly increased (p<0.05) in the muscle of animals fed with LA after the fourth week. Concentration of disulfide bonds was higher in the intestine of fish fed with LA but this group also showed higher concentration of sulfhydryl groups (p<0.05). It is concluded that supplementation with LA is a safe strategy to induce antioxidant responses and improves the antioxidant status in different organs of common carp. Two week of supplementation are required to induce antioxidant responses in intestine and liver and three week for muscle.

Influence of corrugated boundary hydrodynamics on the swimming performance and behaviour of juvenile common carp (Cyprinus carpio)

To facilitate the upstream passage of small fish, corrugated culverts are often preferred over smooth pipes, due to the lower edge and mean cross sectional water velocities created. This benefit could be lost if greater intensities of turbulence induced by wall roughness cause instability and increase the energetic expense of fish locomotion. Common carp (Cyprinus carpio) swimming performance and behaviour were evaluated in a flume using four wall roughness treatments: smooth (control), small (SC), medium (MC), and large (LC) corrugations, dependent on corrugation wavelength and amplitude. Individual fish (n=128, mean±S.D. total length [TL]=86±8mm) swam at a mid-channel velocity of 0.5ms−1 for 30min or until fatigue. Swimming performance was quantified by: (a) success (completion of 30min trial) or failure; and (b) the time to fatigue (endurance) of those that failed. To evaluate behaviour, fish head positions were tracked manually every second. Occupancy of the area within the MC and LC troughs (concave area where velocity was lowest) was recorded and the relationships between trough occupation and (i) TL and (ii) success tested. Differences were tested for between successful and failed individuals, and among treatments, for the following dependent variables: the total distance moved, the mean distance from the flume wall occupied (FishD), and mean velocity (FishU) and turbulent kinetic energy (FishTKE) experienced. Treatment did not influence frequency of success (38–58% per treatment) or time to fatigue. During the MC and LC treatments, troughs were occupied for part of the trial by 56 and 55% of individuals, respectively. Trough occupation was independent of TL in both treatments, and more common for successful fish than failures in the LC treatment. For successful fish, the total distance moved did not differ among treatments. Successful FishD varied among treatments and was higher for the LC (mean±S.E.=93.2±22.3mm) than the SC (33.5±2.8mm) treatment. Despite the availability of lower velocity areas, median successful FishU was higher in the LC treatment (0.51ms−1) than in any other (median=0.47ms−1, 0.44ms−1 and 0.47ms−1 in the MC, SC, and control treatments, respectively). Treatment did not influence successful FishTKE which was consistently low (median=5.3–7.7Jm−3 per treatment). Although occupation of the MC and LC troughs occurred, many individuals spent little time here, and areas with lower TKE were often occupied. Under the experimental conditions created, this study does not support the assumption that low velocity areas created by wall corrugations will improve culvert passage.

Chronic Exposure to Tributyltin Induces Brain Functional Damage in Juvenile Common Carp (Cyprinus carpio)

The aim of the present study was to investigate the effect of Tributyltin (TBT) on brain function and neurotoxicity of freshwater teleost. The effects of long-term exposure to TBT on antioxidant related indices (MDA, malondialdehyde; SOD, superoxide dismutase; CAT, catalase; GR, glutathione reductase; GPx, glutathione peroxidase), Na+-K+-ATPase and neurological parameters (AChE, acetylcholinesterase; MAO, monoamine oxidase; NO, nitric oxide) in the brain of common carp were evaluated. Fish were exposed to sublethal concentrations of TBT (75 ng/L, 0.75 μg/L and 7.5 μg/L) for 15, 30, and 60 days. Based on the results, a low level and short-term TBT-induced stress could not induce the notable responses of the fish brain, but long-term exposure (more than 15 days) to TBT could lead to obvious physiological-biochemical responses (based on the measured parameters). The results also strongly indicated that neurotoxicity of TBT to fish. Thus, the measured physiological responses in fish brain could provide useful information to better understand the mechanisms of TBT-induced bio-toxicity.

Physiological and molecular responses in brain of juvenile common carp (Cyprinus carpio) following exposure to tributyltin.

Tributyltin (TBT), as antifouling paints, is widely present in aquatic environment, but little is known regarding the toxicity of TBT on fish brain. In this study, the effects of exposure to TBT on the antioxidant defense system, Na(+) -K(+) -ATPase activity, neurological enzymes activity and Hsp 70 protein level in brain of juvenile common carp (Cyprinus carpio) were studied. Fish were exposed to sublethal concentrations of TBT (5, 10 and 20 μg/L) for 7 days. Based on the results, with increasing concentrations of TBT, oxidative stress was apparent as reflected by the significant higher levels of oxidative indices, as well as the significant inhibition of all antioxidant enzymes activities. Besides, the activities of Acetylcholinesterase (AChE), Monoamine oxidases (MAO) and Na(+) -K(+) -ATPase were significantly inhibited after exposure to TBT with higher concentrations. In addition, the levels of Hsp 70 protein were evaluated under TBT stress with dose-depended manner. These results suggest that selected physiological responses in fish brain could be used as potential biomarkers for monitoring residual organotin compounds present in aquatic environment.

Effect of wood betony (Stachys lavandulifolia Vahl) extract on some serum biochemical changes and acute stress response in juvenile common carp (Cyprinus carpio)

The effects of four different levels of wood betony (WB) (Stachys lavandulifolia Vahl) extract (0, 2, 4 and 8% W/W in the diet) were investigated on some serum enzymatic activities and acute stress response of juvenile common carp (Cyprinus carpio). After 10 weeks post feeding, two groups of fish (0 and 8% WB) were subjected to handling and crowding stress and the stress responses including serum cortisol, glucose and some electrolytes (Na + , K + and Ca +2 ) levels were assayed. The results revealed that the fish fed on 8% WB had significantly lower levels of lactate dehydrogenase (LDH) and alanine transaminase (ALT) compared to the control group (P 0.05). The potassium and calcium levels showed insignificant fluctuations post stress (P>0.05). Dietary inclusion of WB seems to improve liver function and response to acute stress in juvenile common carp.

Effects of diazinon on some immunological components of common carp, Cyprinus carpio juveniles

The objective of this study was to examine the im- munological effects of diazinon, an organophosphate pesti- cide, on common carp, Cyprinus carpio juveniles. To this end, fish were exposure to sublethal concentrations of diazi- non including 0.1 and 0.2 mg/l for a period of 10 days. The obtained results indicated that diazinon affects the immuno- logical parameters of common carp including lysozyme activ- ity and immunoglobulin (IgM) concentrations. In this regard, the values of lysozyme activity were higher in diazinon treat- ments compared to control group. In contrast, in diazinon treatments, the IgM concentrations were lower than in control group. There were no significant differences in lysozyme ac- tivity between diazinon treatments while IgM concentrations showed a dose-dependent pattern in relation to diazinon con- centrations. In conclusion, our results showed that diazinon can suppress the immunity of common carp juveniles through decreasing IgM levels as well as stimulates lysozyme activity.