Effects of poultry litter on the chronic toxicity of cadmium to common carp (Cyprinus carpio)

Static 90 day bioassays were made in outdoor cement tanks (300 l capacity) with fries of common carp (Cyprinus carpio) exposed to 1.0, 2.5 and 5.0 mg/l of cadmium (Cd) treated individually and with 250 mg/l poultry litter. Addition of poultry litter significantly reduced the concentrations of dissolved Cd in water and whole body Cd in fish and plankton. In contrast, concentrations of total Cd in sediment increased under the influence of poultry litter. Cadmium showed a distinct partitioning pattern in the sediment. Addition of poultry litter did not change the partitioning pattern. Growth of fish, in respect to length and weight, was reduced by all levels of Cd exposure. In contrast, maximum weight gains, increased lengths, increased specific growth rates and yields were recorded under the influence of poultry litter alone. Addition of poultry litter reduced the ill effects on growth of fish produced by Cd and proved to be a promising tool to counter Cd pollution in aquaculture.     

Temperature acclimation of gross cardiovascular morphology in common carp (Cyprinus carpio)

Temperature is of fundamental importance in the functioning of the cardiovascular system of ectothermic fish, with cold-induced ventricular hypertrophy and increased red muscle mass being reported in a number of fish species upon cold acclimation. This study demonstrates a non-linear cold-induced ventricular hypertrophy in common carp (relative ventricular mass (RVM)=0.086±0.003%, 0.074±0.005% and 0.074±0.004% at 5, 15 and 25 °C, respectively), but a cold-induced atrophy of the lateral red muscle mass (RMM) with respect to total muscle mass (2.504±0.554%, 3.982±0.818% and 4.490±0.256% at 5, 15 and 25 °C, respectively). The ventricular hypertrophy in carp acclimated to 5 °C reflects a compensation against the increased workload of pumping viscous blood at low temperatures and the negative inotropic effects of the cold, whereas atrophy of the red muscle is likely due to disuse resulting from reduced locomotory activity in the cold.     

Genetic characterization of common carp (Cyprinus carpio) populations from Greece using mitochondrial DNA sequences

Wild common carp from two lakes and two rivers in Greece were genetically characterized with sequencing analysis of two mitochondrial DNA segments: cytochrome b (1119 bp) and D-loop (646 bp). A total of 9 variable singleton sites and 7 unique haplotypes were detected. A common haplotype was found in three out of the four populations examined, which seems to be the ancestral one and represents the European origin of common carp from Greece. This haplotype could be also justified by the introductions reported with individuals belonging to the Central European race, into many natural habitats in Greece. Limited genetic variation — in Evros and Aliakmonas populations — could be due to bottleneck effects and small effective population sizes, whereas the different haplotypes found in Lake Volvi could represent different common carp stocks. Values of sequence divergence among Greek haplotypes ranged from 0.0006 to 0.0023. The Neighbour-Joining (NJ) phylogenetic tree constructed based on the combined sequences, reveals that the populations of common carp from Greece belong to the European group of populations — which is highly divergent from the South East-Asia cluster — and to the subspecies Cyprinus carpio carpio.     

Field and laboratory investigations of the thermal influence on tissue-specific Hsp70 levels in common carp (Cyprinus carpio)

Thermal discharge from power stations can affect normal environmental conditions and change in heat shock proteins expression of native fish with increasing temperature. In this study, we investigated levels of Hsp70 in the heart, kidney, brain and gill of the common carp Cyprinus carpio both in long-term heat discharge environment and after 24 h acute heat shock exposure. In laboratory exposure experiments, fish acclimated at 10 °C were exposed to various elevated temperatures (20, 24 and 28 °C). Hsp70 concentrations were determined in tissues by Western blotting analysis after one dimensional SDS-PAGE separation. In the field study, the level of Hsp70 in the gill of the carp remained at control values, and Hsp70 expression in the heart, kidney and brain underwent a 2.8 to 3.7-fold increase. A lower thermal sensitivity of the Hsp70 response of the brain, compared with the heart, kidney and gill, was observed in the laboratory experiments. Our data show that these tissues had different levels of Hsp70 responses to thermal influence both in acute exposure and long-term acclimation. The pattern of tissue Hsp70 expression may have a close relationship with the thermal tolerance of the carp and allows the fish to survive long-term thermal pollution.     

Stress response to daily temperature fluctuations in common carp, Cyprinus carpio L.

The littoral zone of lakes and lagoons is often used by fish for feeding or reproduction. However, the large changes in temperature that are typical of natural environments, including the littoral zone, represent a potential stressor for fish. Despite the importance of this habitat, little is known about the effect of daily temperature fluctuations on the stress responses of fish. We monitored daily temperature changes in the near-shore and offshore regions of a natural lagoon between May and July 2008–2010. We observed large temperature fluctuations more frequently in the near-shore zone than the offshore zone. We then exposed common carp (Cyprinus carpio) to a temperature regime similar to that observed in the near-shore zone and measured the levels of cortisol released into the water. The rate of cortisol release increased when carp were exposed to an increase in temperature of ~0.6°C/h over a 5-h period. Conversely, there was no change in the rate of release when temperatures decreased. Our results highlight the importance of maintaining high temporal resolution when evaluating the stress response to daily fluctuations temperature.     

Quantitative genetic estimates of growth-related traits in the common carp (Cyprinus carpio L.): A review

The common carp (Cyrpinus carpio L.) is the oldest cultured and the most domesticated fish species, as well as one of the most important freshwater fishes in the world. However, scientific studies on evaluating the growth-related quantitative traits in this fish are limited. Heritability, the most important parameter in selective breeding programs, was extensively studied for the growth-related traits. The values varied widely among the experiments and methods used because of the existence of common environmental, dominance and maternal effects. However, correlations in phenotypic and genetic levels first evaluated several years ago were limited. On the other hand, heterosis was widely reported and easily obtained for growth-related traits in the common carp. Meanwhile, genotype environment interaction and prediction of breeding values have been studied recently, and are very important in conducting selective breeding programs. The developmental quantitative genetics of growth-related traits was first analyzed in the common carp for reasonable selection during ontogeny. It is expected that genetic improvement will be achieved by carrying out direct selective breeding in the common carp.     

The influence of acclimation and experimental temperature on glutamate dehydrogenase of carp red lateral muscle (Cyprinus carpio L.)

The dependence of the reaction catalysed by carp red lateral muscle glutamate-dehydrogenase on acclimation and experimental temperature was studied. In addition to quantitative aspects of enzyme temperature compensation, the influence of temperature conditions on kinetic characteristics of the enzyme protein is reported. Results are discussed with respect to temperature capacity adaptation (acclimation).     

The effects of ghrelin on the in vitro spontaneous and sGnRH-A stimulated luteinizing hormone (LH) release from the pituitary cells of common carp (Cyprinus carpio L.)

In fish, like in mammals, ghrelin affects gonadotropin release acting at the level of the hypothalamus as well as directly on the pituitary gland. In the present study, enzymatically dispersed pituitary cells obtained from sexually mature male and female carp (Cyprinus carpio L.) were incubated in the presence of human ghrelin at the concentration of 10^− 7 or 10^− 6 M, salmon GnRH analogue (Des-Gly¹⁰, D-Arg⁶, Trp⁷, Leu⁸, Pro⁹)-LHRH (sGnRH-A) at the concentration of 10^− 8 M or the combination of ghrelin (both concentrations) and sGnRH-A. ELISA method was used for carp LH levels determination in the media collected after 10 or 24 h of incubation. Ghrelin at the concentration of 10^− 6 M caused the increase of the spontaneous LH secretion from female pituitary cells only. The combination of ghrelin (both concentrations) with sGnRH-A resulted in the significant elevation of LH levels in the incubations of both male and female pituitary cells in comparison with control incubations as well as with sGnRH-A alone treated cells. The results obtained in this study show that ghrelin functions as LH-stimulating hormone in common carp and that it acts directly on gonadotrophic cells, potentiating also the action of GnRH.     

Swimming, grazing and social behaviour of rohu Labeo rohita (Hamilton) and common carp Cyprinus carpio (L.) in tanks under fed and non-fed conditions

Fish behaviour was monitored in 1-m² tanks each stocked with three 67-g rohu (Labeo rohita). In addition, 80-g common carp (Cyprinus carpio) were stocked at 0, 1 or 2 fish per tank. All tanks were fertilized prior to stocking to stimulate natural food production. In addition, half of the tanks were fed a supplemental diet. Results confirm the general view that rohu mainly lives and feeds in the water column, while common carp is a bottom feeder. In the presence of common carp, rohu increased the time spend grazing on tank wall and bottom, and decreasing grazing time in the water column. Supplemental feeding had a similar, be it less pronounced effect. When both present, rohu and common carp spend 47–52% of their time together. Rohu spends more time close to the bottom in the presence of common carp than when no common carp is present, presumably to profit from increased zooplankton production, triggered by the resuspension of nutrients by burrowing common carp. This was reflected in a higher growth rate of rohu in the presence of carp. These effects were stronger with one common carp per tank than with two common carp. In this study, the results from behavioural observations in tanks nicely complemented results from a pond study analyzing growth, production and food availability. Behavioural observations in tank yielded useful additional information helpful to clarify species interactions and feeding ecology in polyculture ponds.     

Phylogenetic relationships of silver crusian carp Carassius auratus gibelio, C. auratus cuvieri, crucian carp Carassius carassius, and common carp Cyprinus carpio as inferred from mitochondrial DNA variation

PCR-RFLP analysis of the ND3/ND4L/ND4 and 12S/16S rRNA regions and nucleotide sequence variation of the cytochrome b gene were used to study the mtDNA divergence in species of the family Cyprinidae, to examine the phylogenetic relationships of the species, and to identify their taxonomic status. The results indicated that an ancestral form diverged into silver crucian carp and crucian carp after its separation from the common carp lineage. The divergence of continental Carassius auratus gibelio and Japanese C. auratus cuvieri occurred more recently. Two well distinguishable mtDNA phylogroups, suggesting divergent evolution, were observed in continental C. auratus gibelio populations. The divergence was possibly related to the formation of two silver crucian carp groups with different types of reproduction, triploid gynogenetic and diploid gonochoric. At the same time, the results supported the high probability of current genetic exchange between the forms. In view of these findings and high morphological similarity of the two forms, they were not considered to be separate species.     

The effects of water temperature and ration size on growth and body composition of fry of common carp, Cyprinus carpio

Experiment was conducted with the aim of determining the effect of varying water temperature and ration size on growth and body composition of fry of the common carp, Cyprinus carpio. Common carp fry with an initial body weight (BW) of 0.86 g were fed a diet (34.9% protein, 18.3 KJ/g diet) at four ration sizes 4%, 5%, 6% and 7% of their body weight per day and reared at two water temperatures 28 and 32 °C for 60 days. Fry fed with 6% ration showed the highest mean final body weight at 28 °C. Final body weight was significantly (P<0.05) affected by ration and temperature. Cyprinus carpio fry raised at 28 °C had higher feed efficiency (FE) (44.36%) than the fry reared at 32 °C (40.98%) with 4% ration. Further, feed efficiency decreased with increase in ration levels in both temperatures. Protein efficiency ratio (PER) was higher (1.26) at 28 °C than at 32 °C (1.17). At 6% ration, common carp fry showed highest specific growth rate (SGR) (3.82%/day) at 28 °C as compared with at 32 °C (3.57%/day). A linear increase in protein and lipid contents was evident with increasing ration levels up to 6% body weight at both temperatures 28 and 32 °C. Second-order polynomial regression analysis of weight gain and SGR indicated the breakpoints at ration level 6.04% and 6.08% body weight per day at 28 and 32 °C. Hepatosomatic index (HSI) not affected by temperature and ration size while, viscerosomatic index (VSI) influenced (P<0.05) by ration size and temperature. Based on the above results, it may be concluded that 6% BW/day ration is optimal for growth of Cyprinus carpio fry at both the temperatures 28 and 32 °C.     

Cloning, characterization, and expression analysis of Toll-like receptor-7 cDNA from common carp, Cyprinus carpio L.

The Toll-like receptor 7 (TLR7) is activated by single strand RNA and RNA-like compounds (imidazoquinoline), and it induces interferon production. We identified and described carp TLR7 cDNA and its mRNA expression. The full-length cDNA of carp TLR7 gene is 3427 bp, encoding 1049 amino acids (AB553573). The similarities of carp TLR7 with zebrafish, rainbow trout, fugu, and human TLR7 were 89.6, 83.4, 80.6 and 74.6%, respectively, at the amino acid sequence level. Furthermore, the expression of TLR7 mRNA was investigated in normal tissues of carp by semi-quantitative RT-PCR analysis. Carp TLR7 expression was exhibited in healthy tissues (kidney, brain, spleen, skin, intestine, muscle, liver, gills and heart) and though the expression level in each tissue varied among healthy fish. Carp TLR7 expression was significantly increased in head kidney stimulated with TLR7 agonist, imiquimod, at 8, 24 and 48 h in vitro when compared to expression in the control group. Moreover, carp head kidney leukocytes produced elevated levels of pro-inflammatory and type 1 interferon cytokine mRNA in response to imiquimod stimulation.     

Changes in the respiratory properties of the blood in the carp,Cyprinus carpio, induced by diurnal variation in ambient oxygen tension

Summary Effects of diurnal variation in ambient oxygen tension on acid-base balance and blood respiratory properties were investigated in carp (Cyprinus carpio). The carp were subjected to two cycles in ambient between about 130 mm Hg and about 12 mm Hg at 17°C (cf. Figs. 1 and 2). The first period of hypoxia was characterized by a non-compensated respiratory alkalosis, i.e. whole blood showed an increase in pH from 7.92 to 8.14. During the second hypoxic period, 24 h later, a significantly smaller respiratory alkalosis was present, whole blood pH changed from 7.95 (the value found during the intermediate return to normoxia) to 8.08. The latter increase was associated with a significant increase of 25% in plasma bicarbonate concentration compared with the first period of hypoxia (Fig. 1, Table 1). The erythrocytic concentrations of hemoglobin and ATP were lowered by about 10%, compared with the normoxic values, during the two episodes of hypoxia, and this was due to a swelling of the erythrocytes during hypoxia. The red cell GTP concentration showed an altogether different change during the O₂ cycling: the absolute concentration of red cell GTP changed to a steady level, 50% below that present at the onset of the experiment and the major part of this change took place between the two hypoxic periods (Fig. 2, Table 2).The results are discussed with reference to the respiratory function of the blood of carps during subjection to cyclic changes in nature.     

Cathepsins B, H and L in Peritoneal Macrophages and Hepatopancreas of Carp Cyprinus carpio

Cathepsin B was purified from the crude extract of carp hepatopancreas by a modified method, and the specific activity increased about 3,400-fold with a 17% recovery. The purified enzyme gave a single protein band on Native-PAGE, whereas two bands with molecular weights of 30,000 (single chain) and 26,000 (heavy chain) migrated on SDS-PAGE. The enzyme potently hydrolyzed Z-Arg-Arg-MCA and Z-Phe-Arg-MCA but lacked the ability to hydrolyze most of the other MCA substrates. The kinetic constants of the enzyme with two Z-blocked substrates revealed that V_max and K_cat values of Z-Phe-Arg-MCA were much higher than Z-Arg-Arg-MCA, while their K_m values were approximate. The optimum hydrolysis pH and temperature of the enzyme for these two substrates were determined to be pH 6.0 and 45°C, respectively. A variety of protease inhibitors such as E-64, DTNB, antipain, leupeptin, chymostatin, TLCK and TPCK and metal compounds such as CuCl₂, CdCl₂, HgCl₂, and Zn(CH₃COO)₂ were able to significantly inactivate the enzyme. In contrast, cysteine and 2-mercaptoethanol activated the enzyme, with cysteine being more effective for activation than 2-mercaptoethanol over the tested concentrations.     

Phasic influences of vagal stimulation on atrioventricular conduction

The beat-by-beat changes in atrioventricular (AV) conduction evoked by constant frequency and phase-coupled vagal stimulation were examined both qualitatively and quantitatively in 13 anesthetized dogs. The effects of pacing cycle length and sympathetic activity on the vagally induced phasic changes in AV conduction were also characterized. When the vagal stimulus interval was nearly equal to the pacing cycle length and the vagal stimulus moved progressively through the cardiac cycle, AV interval oscillated in a rhythmic fashion. The rhythmicity of the vagally induced AV interval oscillations was altered substantially by changes in either the vagal stimulus interval or the pacing cycle length. The vagally induced AV interval oscillations were abolished during phase-coupled vagal stimulation; however, the magnitude of the resultant steady-state AV interval depended on the time relative to the phase of the cardiac cycle that the vagal stimulus was delivered. In the presence or absence of sympathetic stimulation, a vagal stimulus falling approximately 200 ms prior to atrial depolarization evoked the greatest prolongation in AV interval, regardless of the pacing cycle length. Additionally, the effects of combined sympathetic and phase-dependent vagal stimulation on the AV interval were additive. These data confirm that the influence of a vagal stimulus on AV interval can be predicted from the phase in the cardiac cycle that the vagal stimulus is delivered. Moreover, this phase dependency of vagal effects evokes marked qualitative variations in AV interval response patterns when either the vagal stimulus interval or the pacing cycle length is altered.     

Protective effects of propolis on cryopreservation of common carp (Cyprinus carpio) sperm

Cryopreservation of sperm is common procedures in aquaculture, particularly used for routine in artificial insemination. However, these application cause damages and adversely affected sperm motility, viability and consequently lower hatching rates. The objective of this study is to determine whether propolis has an effect on cryopreservation and fertilization ability and to investigate the potential protective effect of propolis on spermatozoa of Cyprinus carpio. Many studies have been done in cryopreservation offish spermatozoa, but none of them contain propolis in extender composition. The extenders were prepared by using modified Kurokura Solution to which 10% Me₂SO added with different levels of propolis (0.2, 0.4, 0.6, 0.8 and 1 mg ml⁻¹) and 10% egg yolk (as a control without propolis). The pooled semen samples diluted at the ratio of 1:9 by the extenders were subjected to cryopreservation. The percentage and duration of motility and fertilization tests of cryopreserved sperm samples have been done immediately after thawing and compared with control and fresh semen. The extenders containing propolis exhibited higher percentage motility and motility duration than control group (P < 0.05). Especially the group IV (0.8 mg ml⁻¹ propolis) and the group V (1 mg ml⁻¹ propolis) showed significant positive effects on both post thaw motility and hatching ability. The propolis maintained the integrity of the spermatozoa during the cryopreservation process. Evaluating with its contents, it has been shown that propolis is an appropriate cryoprotective agent in fish semen.