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.     

Factors influencing fatty acid composition of common carp (Cyprinus carpio) muscle

There is evidence that n-3 highly unsaturated fatty acids (n-3 HUFA), especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are beneficial for human health, especially for the cardiovascular system. The sources of n-3 HUFA, including EPA and DHA, are scarce in diet consumed by the Czech population. Thus, it would be beneficial to generally increase fish consumption and also to increase the content of the beneficial fatty acids (FA) in locally produced fish and other products. Therefore the overall aim of this paper was to review factors influencing lipid content and composition in common carp, which is the major cultured fish in the Czech Republic, and to identify long term sustainable ways for increasing the beneficial fatty acids in the carp flesh. We conclude that there are several ways to improve the FA composition of common carp in the traditional pond production. High amount of natural food, good supplemental diet containing high level of alpha-linolenic acid (ALA) and suitable processing and cooking were identified as the most important ones.     

The role of CcTpt1 in scale and early embryo development in common carp (Cyprinus carpio, Cyprinidae)

The full length cDNA sequence of the Tpt1/TCTP (Tumor protein, Translationally-controlled1) gene was identified from Common Carp (Cyprinus carpio, Cyprinidae), and was designated as CcTpt1 gene. The CDS is 510 bp and encodes a 170-amino acid peptide with a typical Tpt1 signature 2 domain, and is a typical Tpt1 protein. The deduced amino acid sequence of Tpt1 shared significant identity with the Tpt1 from other animals. A phylogenetic tree analysis revealed that the Common Carp Tpt1 protein has the closest genetic relationship and evolutional distance with Tpt1 from Medaka (Oryzias Latipes). Analysis by RT-PCR showed that the Tpt1 mRNA was detected in heart, liver, gill, kidney, muscle and skin. In embryogenesis, the Tpt1 mRNA was expressed gradually stronger from two-cell stage until prim-5 stage by whole-mount in situ. In larval stage, the Tpt1 was specifically expressed at eyes and brain, later at the ear stone, intestines, gills and internal organs. In addition, the Tpt1 was also found to be expressed in skin matrix being developed into scales and gradually disappeared when the scales were fully formed. These data suggested that the CcTpt1 may play important roles in early embryogenesis and scale initiation in fish.     

Monoclonal antibodies against spermatozoa of the common carp (Cyprinus carpio L.)

Summary Eleven monoclonal antibodies that recognize membrane determinants on spermatozoa of the carp Cyprinus carpio L. have been produced. Indirect immunofluorescence revealed that these determinants are uniformly distributed on the surface of head and midpiece. Most of them are also present on the outer membrane of precursor sperm cells. Although none of the monoclonal antibodies reacted with carp somatic tissue, five monoclonal antibodies were positive for surface membrane determinants of oogonia and early prophase oocytes in carp ovary. Preliminary analysis of the testis and ovary of three other species of fish showed that some carp determinants are shared with germ cells from Barbus conchonius, Clarias lazera, or Salmo gairdneri.Abbreviation WCS Wageningen Carp Sperm antibody     

The reserpine effects on the gonadotrophic cells of the male common carp Cyprinus carpio (Osteichtyes: Cyprinidae)

The secretion of gonadotropins (GtH) in goldfish and carp, is stimulated by GtH-releasing hormone (GnRH) and is inhibited by dopamine. Studies with antidopaminergics have demonstrated to be effective in order to stimulate the spermiation and the ovulation in different species of teleosts. The reserpine, a drug that deplets the dopamine, has shown to stimulate the spermiation in the common carp. We report here, the effects of reserpine on the number and volume of gonadotrophic cells of the common carp. Eight injections of reserpine alone, at doses of 0.5, 1.0 or 1.5 mg/ml/kg of body weight and at intervals of 48 hours, caused an increase in the number and volume of gonadotrophic cells. The dose 0.5 mg/ml/kg, presented an increase in the number and volume of gonadotrophic cells of 382% and 123%, respectively, above the control group. The dose 1.0 mg/ml/kg, showed an enhanced number and volume of gonadotrophic cells of 704% and 152%, respectively. With the dose 1.5 mg/ml/kg increase in number (171%) and volume (106%) of gonadotrophic cells was lower. The gonads of the experimental groups had an abundance of advanced states of spermatogenesis. Our results show that eight intraperitoneal injections of reserpine were responsible for an increase in gonadodrophic cell, number and volume.     

Texture analysis in liver of common carp (Cyprinus carpio) sub-chronically exposed to perfluorooctanoic acid

An operator-neutral, objective method was implemented to comparatively assess liver pathology in 30 specimens of common carp (Cyprinus carpio): 20 after experimental flow-through exposure to two perfluorooctanoic acid (PFOA) dosages (10 fish exposed to 200 ng l⁻¹ and 10 fish exposed to 2 mg l⁻¹) for 56 days and 10 unexposed (negative control). The method relies on texture analysis as a complementary approach to traditional histopathology and chemical dosage analysis performed previously on the same experimental material. Texture features data were analyzed by means of Redundancy Analysis (RDA), Linear Discriminant Analysis (LDA) and Canonical Variates Analysis (CVA). LDA resulted in the correct classification of 80% of cases (24 out of 30 cases) with a sensitivity of 83.3% and a specificity of 83.3. In particular, four male samples from the low dosage group (200 ng l⁻¹) were misclassified as unexposed fish and two female samples from the unexposed group were misclassified as low dosage exposed. Nevertheless, PFOA liver chemical dosage analysis results were the same both in unexposed and in low dosage group fish, all below the limit of detection. No sample from the high dosage group (2 mg l⁻¹) has ever been misclassified. Interestingly, texture features correlated with the PFOA concentrations detected in the liver of each sampled fish. In the present study the technique of texture analysis was combined with techniques of multivariate exploratory data analysis (RDA, LDA/CVA). This approach resulted in a robust, sufficiently sensitive and specific means to study PFOA-induced liver pathology. The new method can discriminate between unexposed and two PFOA exposed groups with better confidence and in a more affordable way, compared to chemical quantification of liver PFOA. The texture features correlated well with liver PFOA concentrations and objectively quantified degenerative liver morphology. In conclusion the overall approach may be a suitable candidate as a reliable and broad-ranging method for biomarker analysis of exposure and effect.     

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.     

Molecular cloning of the common carp (Cyprinus carpio) rhodopsin cDNA

A recombinant phage clone containing a 1584 nucleotides rhodopsin cDNA was screened from a carp retinal cDNA library. The inserted DNA consisting of a single open reading frame of 1062 nucleotides at positions 72 to 1133 encodes a 354 amino acid polypeptide. The deduced amino acid sequence of carp rhodopsin showed 95.7, 85.5 and 74.4% identity with that of goldfish, sand goby and lamprey, respectively. The sites of palmitoylation, glycosylation, disulfide bond formation and Schiff base formation in the putative rhodopsin are all conserved.     

Occurrence of Atractolytocestus huronensis (Cestoda, Caryophyllaeidae) in German pond-farmed common carp Cyprinus carpio

Up to now, the caryophyllid cestode Atractolytocestus huronensis Anthony, 1958, a parasite of common carp, has attracted little attention in Germany. Based on recent publications from the Czech Republic and Hungary, it appears probable that this cestode may be increasingly common in Germany. There is a strong connection between the occurrence of A. huronensis and imports of common carp from the Czech Republic and southern Germany. Although in most cases no clinical alterations in parasitized carp have been observed, care should be taken to avoid further dissemination and to prevent possible losses in commercial pond farming.     

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.     

Interactions of common carp (Cyprinus carpio) with benthic crayfish decapods in shallow ponds

Introduction of common carp (Cyprinus carpio) for aquaculture increased in recent decades. This fish is now established in many new water systems creating interactions with native species. Some of these interactions have been partly understood, but most of them remain unknown. For instance, in shallow ponds of central Mexico, populations of crayfish (Cambarellus montezumae) are reduced with high carp densities, but little is known about the mechanisms that lead to this depletion. Gut analysis showed that carp ate mostly detritus, small invertebrates, plant tissues and seeds, reducing the possibility of predation as a main cause of crayfish population reduction. Field and experimental data suggest that the effect of carp on crayfish is associated with habitat depletion. Submerged macrophyte Potamogeton pectinatus and the algae Cladophora glomerata are important components in crayfish habitat, and their coverage in the water system is affected by carp presence. A second effect of carp on crayfish populations is associated with the alteration of crayfish behaviour. Crayfish displacement speed increased significantly in the presence of carp.     

Genetic control of glucosephosphate isomerase (GPI) in common carp (Cyprinus carpio L.)

In common carp, a freshwater fish species of tetraploid origin, GPI enzymes are present in two variants: GPI-A and GPI-B. GPI-A is coded by two loci segregating for two (GPI-A 1*) and six (GPI-A2*) alleles. Experimental crosses of the ornamental (Koi) variety of common carp revealed that GPI-B is coded by only one locus (GPI-B*). Another GPI-B* locus must have been silenced in the process of functional diploidization. It was also shown that the GPI-A2* locus segregated independently from the GPI-B* locus, demonstrating that the loci are located on different chromosomes.     

The ultrastructure of leucocytes in carp (Cyprinus carpio)

Leucocytes from anterior kidney, middle kidney, spleen, thymus and peripheral blood of Common carp were examined. Lymphocytes were found to have a similar fine structure to that of mammals. Thrombocytes had a similar appearance to lymphocytes, but the former were sometimes distinguishable by vesicles in series and/or microtubules below the plasma membrane. Blast cells, monocytes and clearly identifiable plasma cells were also seen. Neutrophils had varying proportions of at least two types of granules, which often presented inclusions. Owing to their different granules, eosinophils and basophils were morphologically distinguishable, but differentiated cells with equal proportions of the two types of granules were also seen. In addition, cells of uncertain nature, possessing rod-shaped granules, were observed. The different leucocyte types showed the same morphology in the different lymphoid organs and in peripheral blood, although they were present in different proportions.     

PCR-cloning and gene expression studies in common carp (Cyprinus carpio) insulin-like growth factor-II

Insulin-like growth factor-II (IGF-II) is a member of a growth factor family related to fetal growth in mammals but its physiological role has not been clearly identified in fish. In teleosts, the basic mechanism of the growth hormone (GH)-IGF axis is known to be operative but in a different manner. For instance, IGF-I exhibits GH dependence whereas for IGF-II, its GH dependence varies in different fish species. In this study, we used polymerase chain reaction (PCR) to obtain a common carp IGF-II (ccIGF-II) cDNA fragment and methods of rapid amplification of cDNA ends (RACEs) to obtain a full-length ccIGF-II sequence. The ccIGF-II encodes for a predicted amino acid sequence showing identities of 70.6%, 68.7%, 63.4% and 35% in comparison with salmon, barramundi, tilapia and human IGF-II, respectively. The nucleotide identity between the open reading frame (ORF) of the ccIGF-II and ccIGF-I cDNA sequence is only 36.2%. Distribution of ccIGF-II mRNA levels in common carp tissues was also studied; ccIGF-II expressed in hepatopancreas, heart, and many other tissues in adult carps are similar to the levels of ccIGF-I except in gills and testis. ccIGF-II levels were significantly higher than that of ccIGF-I in most juvenile tissues except in hepatopancreas, where ccIGF-I was higher (threefold) than that of ccIGF-II. The levels of ccIGF-I were also higher than ccIGF-II in carp larvae, from pre-hatched stage to day 30 post-hatching. Injection of porcine GH (pGH) increased the IGF-I and IGF-II mRNA levels in the hepatopancreas and brain of juvenile carps. However, hepatic IGF-I mRNA levels were induced more than IGF-II by pGH, whereas ccIGF-II levels gave a higher response than IGF-I in the brain in response to GH induction.