Response of common carp (Cyprinus carpio L.) leucocytes to hormone-induced stress

The influence of cortisone on leucocytes composition in the blood of common carp (Cyprinus carpio L.) is studied. Following the hormone injection, the relative number of leucocytes decreased and the number of neutrophils and blast-form cells increased in the leucocyte spectrum of experimental fish.     

Cadmium-binding to transferrin in the plasma of the common carp Cyprinus carpio

In this study, it was investigated by autoradiography with radioactive cadmium after Western blotting of two-dimensional electrophoresis gels, to which proteins cadmium is mainly bound in plasma of common carp Cyprinus carpio. The obtained results demonstrate that in carp plasma, cadmium is primarily bound to two high molecular weight proteins. Relative small amounts are bound to a protein with M(r) approximately 60000. The other metal-binding protein, with M(r) approximately 70000 and pI approximately 6.7 was identified as transferrin. The conditional equilibrium constants for the binding of cadmium ions to the two metal-binding sites of this protein were calculated as logK(1)=5.40+/-0.12 and logK(2)=4.66+/-0.21, which are comparable to those of human transferrin under the same experimental conditions. Transport of cadmium in plasma of carp was found to be different from that of brown trout Salmo trutta and man, where cadmium is mainly bound to albumin and transferrin. The prominent binding of cadmium to transferrin can be explained by the absence or at least the very low concentrations in which albumin is present in carp plasma.     

Oral absorption of biologically active insulin in common carp (Cyprinus carpio L.).

1. Bovine insulin dissolved in 0.05 M deoxycholic acid was absorbed through oral intubation in fish weighing 200-300 g. 2. The peak of absorption appeared in all fish, 30-45 min after intubation and was followed by a gradual decrease. The extent of absorption was extremely variable, with up to a 20-fold difference between individuals. No detectable insulin was found in fish intubated with vehicle. 3. The absorbed hormone retained 17-88% of its lipogenic bioactivity in vitro. The absorbed insulin lowered the levels of several amino acids in the intubated fish, indirectly indicating that its bioactivity was also retained in vivo.     

Gonadotropin response to GnRH during sexual ontogeny in the common carp, Cyprinus carpio

This study was designed to reveal whether gonadotropic response to GnRH in the common carp (Cyprinus carpio) changes during sexual ontogeny and whether the response of FSHbeta and LHbeta subunits is uniform or differential. The study comprised fish at the following stages: juveniles (4-month-old females with primary oocytes and early spermatogenic males); maturing (9-month-old previtellogenic females and advanced spermatogenic males); and mature (16-month-old postvitellogenic females and spermiating males). Fish were injected with superactive salmon GnRH analogue (sGnRHa; 25 microg/kg) and blood was sampled 6, 12 and 24 h later for cGtH (LH) and sex steroid levels. Pituitaries were taken for determination of FSHbeta and LHbeta mRNA levels by slot-blot hybridization and for cGTH content in the same glands by radioimmunoassay (RIA). Values were compared with the levels prior to sGnRHa administration and with control fish sampled at the same intervals. Juvenile fish did not respond at all to sGnRHa. In maturing females, FSHbeta mRNA increased by >300%, while that of LHbeta increased by 200%. In maturing males, FSHbeta mRNA did not change and only a slight increase occurred in that of LHbeta. In 16-month-old postvitellogenic females, there was no response of FSHbeta mRNA, while that of LHbeta dramatically increased. In spermiating males of the same age, mRNA of both FSHbeta and LHbeta increased following sGnRHa injection. Immunoreactive cGtH was present in the pituitary and plasma of all fish examined, but in juveniles it did not change following sGnRHa injection. In maturing and mature fish of both genders, sGnRHa administration was followed by a marked increase in circulating cGtH, concomitant with a decrease in its pituitary content, indicating the limited amount of the hormone stored in the gland. In conclusion, the response of the gonadotropin subunit mRNAs in the common carp was found to be differential and dependent on the gender and the phase of sexual ontogeny.     

Reactivation of koi herpesvirus infections in common carp Cyprinus carpio

Two co-habitation studies with common carp were conducted to determine whether latent infections of koi herpesvirus (KHV) exist. Fish were exposed to KHV using 2 different temperature profiles, which induced low and high initial mortality. Subsequently, certain groups of fish were co-habited with naive fish while others were not. Koi herpesvirus was reactivated in fish from 3 of the 5 experimental tanks. Reactivation of the virus occurred regardless of the initial mortality associated with the virus or whether fish were co-habited with naive fish. The reactivation of the virus in our experiments occurred several months after the initial exposure to KHV and appeared to be temperature dependent.     

Gluconeogenic enzyme gene expression is decreased by dietary carbohydrates in common carp (Cyprinus carpio) and gilthead seabream (Sparus aurata)

Our objective is to understand the low metabolic utilization of dietary carbohydrates in fish. We compared the regulation of gluconeogenic enzymes at a molecular level in two fish species, the common carp (Cyprinus carpio) and gilthead seabream (Sparus aurata), known to be relatively tolerant to dietary carbohydrates. After cloning of partial cDNA sequences for three key gluconeogenic enzymes (glucose-6-phosphatase (G6Pase), fructose biphosphatase (FBPase) and phosphoenolpyruvate carboxykinase (PEPCK) in the two species, we analyzed gene expressions of these enzymes 6 and 24 h after feeding with (20%) or without carbohydrates. Our data show that there is at least one gluconeogenic enzyme strongly regulated (decreased expression after feeding) in the two fish species, i.e. the PEPCK for common carp and G6Pase/FBPase for gilthead seabream. In these fish species, the regulation seems to be similar to the mammals at least at the molecular level.     

Efficacy of quinine against ichthyophthiriasis in common carp Cyprinus carpio

Ichthyophthiriasis, caused by Ichthyophthirius multifiliis, is an economically important worldwide parasitic disease that infects all freshwater fish. Since the banning of malachite green for use in food fish, there has been a great need for alternative therapeutants. The goal of this study was to investigate the efficacy of quinine against I. multifiliis. Parasite developmental stages from our laboratory-established life cycle in rainbow trout Oncorhynchus mykiss were exposed to quinine in vitro, and a dual fluorescent staining technique was used to allow a clear distinction between viable and damaged parasites. Furthermore, the effect of quinine was assessed in vivo by oral administration and intraperitoneal injections in common carp Cyprinus carpio. The results of the in vitro experiments proved quinine to be effective against the parasite. Quinine injected at a dosage of 60 mg kg(-1) body weight resulted in a significantly lower number of trophonts. In contrast, in-feed trials did not show a significant reduction of trophonts after treatment commencing 1 d after infection with concentrations of up to 20 g quinine kg(-1) feed for 3 d. After a 14-d treatment at concentrations of up to 10 g quinine kg(-1) feed prior to theront exposure, there was also no significant difference in parasite numbers between treated and control groups. The results of oral versus parenteral application of quinine indicate that the substance is not completely absorbed from the intestinal tract of common carp. However, medicated feed containing higher concentrations of quinine was less readily accepted by the fish, presumably due to the bitter taste.     

Global patterns and clines in the growth of common carp Cyprinus carpio

This review provides a meta‐analytical assessment of the global patterns and clines in the growth of Cyprinus carpio as measured by length‐at‐age (L_t) or von Bertalanffy growth function (VBGF) parameters, mass–length relationship (W–L_t) and condition factor, based on literature data. In total, 284 studies were retrieved spanning 91 years of research and carried out on 381 waterbodies–locations in 50 countries in all five continents. Although native C. carpio achieved larger (asymptotic) size relative to its non‐native counterpart, the latter grew faster during the first 7 years of life. Lentic populations (especially in natural lakes) also achieved larger sizes relative to lotic ones and the same was true for populations in cold and temperate v. arid climates. Unlike previous studies (on much more restricted datasets), only weak latitudinal clines in instantaneous growth rate, L_t at age 3 and mortality were observed globally and this was probably due to the presence of counter‐gradient growth variation at all representative age classes (i.e. 1–10 years). Slightly negative allometry was revealed by the W–L_t and the related form factor tended to distinguish the more elongated and torpedo‐shaped body typical of the wild form from the deeper body of feral‐domesticated C. carpio. Existing population dynamics models for C. carpio will benefit from the comprehensive range of waterbody type × climate class‐specific VBGF parameters provided in the present study; whereas, more studies are needed on the species' growth in tropical regions and to unravel the possibility of confounding effects on age estimation due to both historical and methodological reasons.     

Determination of the surface area of common carp,Cyprinus carpio L.

A wrap method adaptation combined with AutoCAD2005 and Scion Image for Windows were used to determine the surface area of a fish. Compared with the corresponding r² and F of many models, the most accurate formula: S = 752.15W^0.675 (r² = 0.999, F = 18362.94, P < 0.0001) for estimating the surface area of common carp was obtained. Similarly, the fin formula: S = 1834.12W^0.708 (r² = 0.992, F = 2690.47, P < 0.0001) was also obtained for the same purpose. It was proven that these two formulae gave good estimates of surface and fin areas of four strains of common carp: Yellow‐river carp, fancy carp, mirror carp and Xingguo red carp.     

The effect of dietary protein level and ration level on excretion of ammonia in common carp,Cyprinus carpio

• 1.1. Nitrogenous excretion in the form of ammonia was determined in common carp of 65.0 ± 8.0 g body weight in metabolism chambers. The fish were fed with 20, 35 and 50% dietary protein at 1, 2 and 3% body weight per day ration level.
• 2.2. Nitrogenous excretion as a percentage of ingested food increased with an increase of dietary protein but decreased with an increase of ration level.
• 3.3. The energy lost in excretion ranged from 4.19% with 20% dietary protein at 3% ration level to 8.74% with 50% dietary at 1% ration level.

     

Coping strategies in a strongly schooling fish,the common carp Cyprinus carpio

Individual common carp Cyprinus carpio were screened repeatedly for risk taking (rate of exploration of a novel, potentially dangerous environment) and for competitive ability (success in gaining access to a spatially restricted food source). Marked differences in behaviour were evident, and significant consistency in individual responses across trials was found for both risk taking and competitive ability. In addition, there was a significant positive relationship between individual performance in these two contexts, with fish that explored more quickly in the novel environment tending to be among the first to gain access to restricted food. In two follow‐up studies, resting metabolic rate, blood lactate and glucose and the expression of the cortisol receptor gene in the head kidney and brain were compared in fish from the two extremes of the risk‐taking spectrum. Mass‐specific metabolic rate was significantly higher in risk‐taking than in risk‐avoiding fish, while plasma lactate and glucose concentrations and expression of the cortisol receptor gene were lower. It was concluded that a behavioural syndrome based on boldness and aggression exists in C. carpio, as it does in many other animals, and that this is associated with differences in metabolic and stress physiology (down to the genomic level) similar to those described in animals with different coping strategies.     

Microsatellite markers in common carp (Cyprinus carpio L.)

Microsatellite markers of the poly (CA) type in common carp ( Cyprinus carpio L.) are described. Clones containing a (CA) repeat were isolated from a common carp genomic library and sequenced. The number of repeats found was high compared to mammals but comparable with other teleost fishes. Classification of the repeats (perfect, imperfect and compound) are compared with the Atlantic cod ( Gadus morhua L.), rainbow trout ( Oncorhynchus mykiss ), and Atlantic salmon ( Salmo salar L.). A total of 41 primer sets were designed and tested for polymorphism on a test panel of eight animals (derived from outbred lines, inbred lines and gynogenetic clones). Thirty-two markers were found to be polymorphic. The heterozygosity in the outbred animals was 60·4%, 51·1% in the inbred animals and 0% in the gynogenetic clones. The average number of alleles among the eight animals was 4·7 per marker. Six markers (18·8%) gave an additional polymorphic amplification product besides the polymorphic amplification product in the expected size range. The possibility that these loci are tetraploid is discussed. The polymorphic loci described for common carp will be valuable as genetic markers for use in population, breeding, and evolutionary studies.     

Genetic evolution and diversity of common carp Cyprinus carpio L.

Knowledge of genetic variation and population structure of existing strains of both farmed and wild common carp Cyprinus carpio L. is absolutely necessary for any efficient fish management and/or conservation program. To assess genetic diversity in common carp populations, a variety of molecular markers were analyzed. Of those, microsatellites and mitochondrial DNA were most frequently used in the analysis of genetic diversity and genome evolution of common carp. Using microsatellites showed that the genome evolution in common carp exhibited two waves of rearrangements: one whole-genome duplication (12–16 million years ago) and a more recent wave of segmental duplications occurring between 2.3 and 6.8 million years ago. The genome duplication event has resulted in tetraploidy since the common carp currently harbors a substantial portion of duplicated loci in its genome and twice the number of chromosomes (n = 100–104) of most other cyprinid fishes. The variation in domesticated carp populations is significantly less than that in wild populations, which probably arises from the loss of variation due to founder effects and genetic drift. Genetic differentiation between the European carp C.c. carpio and Asian carp C.c. haematopterus is clearly evident. In Asia, two carp subspecies, C.c. haematopterus and C.c. varidivlaceus, seem to be also genetically distinct.     

Genomic resources and microarrays for the common carp Cyprinus carpio L.

The common carp is an important fish species satisfying ornamental, food and recreational fisheries' needs worldwide, but in common with other cyprinid fishes, it is particularly renowned for its environmental tolerance. Investigating the mechanistic basis of growth, disease and environmental tolerance is greatly enhanced by access to a comprehensive list of gene sequences and post-genomic technologies. The current status of genomic resources is described for this species including 40 k cDNA clone collections, their associated expressed sequence tags (ESTs) and a developing series of 13 k–26 k cDNA microarrays fabricated from amplicons. The arrays have been directed at questions of response to environmental stress (cold and hypoxia), viral and bacterial disease and ectoparasite infection. Consequently, clones from a wide range of tissues were prepared. The authors discuss how these resources were generated and their application. Evidence is presented supporting that the carp microarray may also be useful as a heterologous set of probes in studies of other fish species.     

Preparation and characterization of insulin of carp (Cyprinus carpio).

Insulin of carp (Cyprinus carpio) was isolated and crystallized. The insulin was biologically active in two tests; it decreased the blood glucose level and stimulated 14CO2-formation from glucose. The chemical properties are similar to those of insulins from other species. The insulins of carp and of mammals differ greatly immunologically. Antibodies against carp insulin crossreact with carp proinsulin.     

The eye lens weight and age in the common carp, Cyprinus carpio L.

The validity of the use of the weight of dried eye lenses as an indicator of age in the common carp, Cyprinus carpio L., is tested. There is a significant difference between males and females for fish of two and three years old. Otherwise no significant difference is noted between sexes. The linear relationship between the dry weight of eye lenses and age + 1 are: In Y + 1= 0.5202 + 16.4928 X ( r = 0.93) for female and ln Y + 1=0.4276 + 16.7364 X ( r = 0.94) for male.
The method for determining age is valuable for fish until three years old. However for older fish, in spite of a correlation coefficient between lens weight and age and even with a significant difference between annual groups, the age determination may be misleading due to the overlap in lens weights. In conclusion therefore this method may not be useful for back calculation of growth, for production estimates or studies in which accurate estimates of age are needed.     

Specific dynamic action and feeding metabolism in common carp,Cyprinus carpio L.

• 1.1. Oxygen uptake attributable to Specific Dynamic Action (SDA) was measured in common carp, Cyprinus carpio L. (63.6–84.0 g) fed on 20, 35 and 50% dietary protein at 0.40 to 1.00% ration levels at 28°C.
• 2.2. After feeding both SDA magnitude and mean peak oxygen consumption increased directly with dietary protein and ration levels. SDA duration was not significantly related to dietary protein but significantly increased with ration levels.
• 3.3. SDA coefficients were 8.99, 13.51 and 15.94% with 20, 35 and 50% dietary protein showing a direction relationship to the protein content. The SDA coefficient did not change with ration size.
• 4.4. SDA models resulting from this work are of great interest for the aquaculturist, as post-feeding oxygen requirements in an intensive fish culture can be predicted where dietary protein and ration levels are known.

     

Growth performance and starch utilization in common carp (Cyprinus carpio L.) in response to dietary chromium chloride supplementation

A nutrition trial was conducted on juvenile common carp (Cyprinus carpio), initial mean body weight 15 ± 0.4 g within a controlled facility at 25 ± 0.5 °C. Six diets containing various levels of supplementary Cr (0, 0.2, 0.5, 1.0, 1.5, and 2.0) mg Cr/kg of diet as Cr chloride hexahydrate were fed to carp for a period of 10 weeks. Lower growth performance was observed in fish fed on the control diet and the diet supplemented with the highest level of Cr (2.0 mg Cr/kg). Although fish fed 0.5 mg Cr/kg showed the best growth performance, this was not significantly different (P > 0.05) from fish fed 1.0 mg Cr/kg. The regression of plasma glucose concentration was linear (R² = 0.97 and P value = 0.001) as the Cr content of the diet increased (up to 1.5 mg Cr/kg).Cr carcass content was elevated with an increasing level of dietary Cr supplementation up to 1.5 mg Cr/kg; but fish fed on the diet supplemented with the highest level of Cr (2.0 mg Cr/kg) showed a decrease in Cr carcass content.Histological examination to evaluate the impact of different Cr supplementation on liver and gut tissues showed notable changes. The higher level of Cr (2.0 mg Cr/kg) in the diet gave rise to elevated hepatocyte vacuolization and changes in gut tissue morphology.It appeared that Cr chloride significantly improved growth within a defined range (0.2–1.5) mg Cr/kg without any negative impact, while 2.0 mg Cr/kg in carp diet seems to be the threshold for the initiation of toxicity.