Differences between the European carp (Cyprinus carpio carpio) and the coloured carp (Cyprinus carpio haematopterus) in susceptibility to Thelohanellus nikolskii (Myxosporea) infection

Thelohanellus nikolskii infection of the common carp (Cyprinus carpio L.) has been a common parasitosis in the Central European fish farms since the first detection of the parasite about 20 years ago. This parasite, introduced from the Far East, causes intensive infection on the fins of fingerlings of the carp subspecies cultured in Europe (European carp, Cyprinus carpio carpio). This infection of the common carp occurs in the Hungarian fish farms every year. Until the present study, this parasite had not been recorded from the fins of koi or coloured carp (Cyprinus carpio haematopterus), a carp of Far Eastern origin, which is cultured in Hungary as an ornamental fish. A recent survey conducted in common carp, koi and goldfish stocks demonstrated that T. nikolskii infection of low prevalence and intensity occurs also in koi populations, but its prevalence and intensity are markedly lower than in common carp kept in the same ponds. It is suggested that the observed differences are due to disparities in the susceptibility of the two carp subspecies to T. nikolskii, and that the koi is less susceptible to this infection. Other signs of susceptibility can also be observed in the European subspecies, since in 15% of the fish plasmodium development was arrested at an early stage. Thelohanellus nikolskii infection could not be demonstrated on goldfish (Carassius auratus).     

Epitheliocystis in carp (Cyprinus carpio) in South Korea

Epitheliocystis in the carp of a pet fish market were investigated by our diagnostic work and collecting information from department of laboratory animal medicine and fish & shellfish laboratory. The epitheliocystis was identified by using histopathological examination. Epitheliocystis was confirmed as inflammation, epithelial hyperplasia, and lamellar fusion of the gill tissue. Electron microscopic observation showed that the inclusions were filled with Chlamydia-like organism.     

Mechanism of blood coagulation in common carp (Cyprinus carpio)

In vitro, carp blood was anticoagulated by using MgSO₄ at a final concentration of 22.2 mmol L^?1 and sodium citrate at a final concentration of 11.8 mmol L^?1. The coagulation times for carp plasma diluted by ion‐free water (1:1), and that of carp plasma to which thrombocytes and small lymphocytes were added, were measured at 23 °C using standard methods, and then contrasted with the coagulation times for plasma obtained from chickens and rabbits. The shapes of the thrombocytes and small lymphocytes, which were either wet mounted or stained with hematoxylin and eosin, were observed under a light microscope. We found that: (i) the coagulation reaction of carp blood was significantly (P < 0.01) accelerated by the addition of ion‐free water; (ii) the three types of blood cells (thrombocytes, small lymphocytes and red blood cells) promoted plasma coagulation to a similar extent (P > 0.05); (iii) in carp Mg²⁺ plasma and K₂C₂O₄ plasma, the thrombocytes were usually morphologically normal, but many small lymphocytes were destroyed and became aggregated; (iv) in the citrate plasma, thrombocytes were often aggregated, but the small lymphocytes were usually morphologically normal; and (v) the coagulation time for chicken and rabbit plasma was significantly extended by adding ion‐free water.     

Pox-like lesions in a colony of carp (Cyprinus carpio)

Twelve carp (Cyprinus carpio) out of a total of 100 were affected with skin nodules, mainly located on the dorsal and lateral surface. Post mortem examination of six of the worst affected fish showed the nodules consisting of white gel-like outgrowths. No abnormality was apparent in any other tissue examined. Microscopically, the nodules were formed by proliferating hyperplastic epidermal cells. The other six fish were left for recovery and their nodules regressed spontaneously. The possible aetiological factors are listed.     

Herpesvirus-associated papillomas in koi carp (Cyprinus carpio).

From January through November 1994, 32% (7/22) of koi carp (Cyprinus carpio) maintained in indoor aquariums developed proliferative cutaneous lesions that consisted of single to multiple 2-10-mm whitish to pink fleshy masses usually associated with fin rays. Although scaleless koi were more commonly affected (3/6) than were normally scaled koi (4/16), the difference in incidence rates was not significant (chi2 text, P > 0.05). Lesions typically resolved spontaneously in 1-3 wk, occasionally persisted for >3 mo, and recurred in several fish after 2-5 mo. Fish were otherwise asymptomatic. Wet mount preparations from lesions were densely cellular and consisted of hyperplastic epidermal cells of normal morphology without parasites or inflammatory cells. Histologically, biopsies were consistent with papillomas and were characterized by a marked benign epidermal hyperplasia without inclusion bodies or inflammatory infiltrate. Transmission electron microscopic examination revealed intranuclear and intracytoplasmic herpesvirus virions. Virus isolation attempts were unsuccessful.     

Fish and antibiotics: pharmacokinetics of sulphadimidine in carp (Cyprinus carpio)

Pharmacokinetics, metabolism and clearance of sulphadimidine (SDM) were studied after a single intraperitoneal injection of SDM in carp at 20 degrees C. SDM was acetylated and hydroxylated to a small extent. The main metabolite was N4-acetyl derivative amounting only 2% of the total drug dose excreted; hydroxylation was less important (0.41% of the dose). The elimination half-life for SDM in carp was 17.5 h. The clearance values for SDM and its metabolites were equivalent. The importance of pharmacokinetic studies in different fish species is discussed.     

Myxobolus infections of common carp (Cyprinus carpio) in Syrian fish farms

During a survey on Myxobolus infection of pond-cultured common carp in Syria three Myxobolus spp. were found. Myxobolus dispar infected the gill arteries, forming large elongated plasmodia in the gill filaments. The plasmodia of M basilamellaris were located in the gill arches at the base of the filaments. Elongated filiform plasmodia of M. encephalicus were found in the blood vessels of the brain. Despite the common occurrence of the above parasites, no disease symptoms were observed in the infected fish specimens. This is the first report on myxosporean infection of fish from Syrian waters.     

Fumonisin B1 causes multiple lesions in common carp (Cyprinus carpio)

Year-1 carp were fed ratios containing 100mg/kg and 10 mg/kg of added fumonisin B1 for 42 days. The experimental and control fish were examined clinically during the experiment and at the end all fish were necropsied and histological changes recorded. Blood vessels, liver, exocrine and endocrine pancreas, excretory and haematopoietic kidney, heart and brain were sensitive both to 100 and 10mg/kg of FB1 in the diet and the rodlet cell (RC) frequency was considerably increased in and around damaged tissues. Many damaged blood vessels contained stacks of RCs above the endothelium. Other changes subsequent to fumonisin exposure that have not been previously reported include scattered lesions in the exocrine and endocrine pancreas, and interrenal tissue, probably due to ischemia and/or increased endothelial permeability. Presented findings indicate the need for more intensive studies of fumonisin-induced toxicity in cultured fish.     

The efficacy of alfaxalone for immersion anesthesia in koi carp (Cyprinus carpio)

ObjectiveTo characterize the physiologic and behavioral effects of a single induction dose and two maintenance doses of alfaxalone delivered by water immersion in the anesthesia of koi (Cyprinus carpio).Study designProspective, within-subject complete crossover design.AnimalsSix adult koi (Cyprinus carpio) with a median body weight of 344.5 g (range 292.0–405.0 g).MethodsKoi were immersed in water containing 10 mg L^?1 alfaxalone until immobile and then maintained with alfaxalone at either 1 or 2.5 mg L^?1 via a recirculating water system. Times for anesthetic induction and recovery periods were recorded. Physiologic and blood gas parameters were evaluated before, during and after the anesthetic trial. Response to noxious stimuli was also assessed.ResultsMedian anesthesia induction time for all fish was 5.4 minutes. Median recovery time was 11.8 and 26.4 minutes in the 1.0 and 2.5 mg L^?1 doses, respectively, which were significantly different (p = 0.04). Cessation of opercular movement occurred in 0/6 and 4/6 fish exposed to 1.0 and 2.5 mg L^?1 dose respectively. No difference was observed in median heart rate over the duration of the anesthetic events. Response to noxious stimulation was 4/6 and 0/6 in the 1.0 and 2.5 mg L^?1 doses respectively. Oxygenation and ventilation did not change during the experiment, but there was a significant decrease in blood pH along with an increase in blood lactate concentration.Conclusion and clinical relevanceAdministration of alfaxalone, via water immersion, as an induction and maintenance anesthesia agent provided rapid and reliable anesthesia of koi with no mortality. The maintenance dose of 2.5 mg L^?1 was sufficient to prevent response to noxious stimuli but was associated with a clinically relevant depression in opercular rate.     

Two independent cases of spontaneously occurring branchioblastomas in koi carp (Cyprinus carpio)

This report documents 2 cases of branchioblastomas in koi carp (Cyprinus carpio). Macroscopically, both cases were characterized by well-demarcated, pale red nodular masses located at the left first branchial arch and the right pseudobranch, respectively. Histologically, the neoplasias were composed of blast-like cells that differentiated into cartilage and branchial lamellae embedded in abundant fibrous connective tissue. Based on these findings, a branchioblastoma was diagnosed.     

Morphology of blood cells in carp (Cyprinus carpio L.)

The morphology of blood cells in the carp was investigated by light and electron microscopy. Erythrocytes, thrombocytes, lymphocytes, granulocytes and monocytes were identified as the peripheral blood cells. Thrombocytes were round to long oval, each containing vesicular and microtubular structures and an oval nucleus with abundant heterochromatins. Lymphocytes were divided into three types in size, small, medium and large. Some of the small and medium lymphocytes were alpha-naphthyl-acetate esterase (ANAE) positive, while large lymphocytes were pyroninophilic. Granulocytes were distinguished into three types (type I, type II and type III) according to the morphology of the nucleus and granules. Type I granulocytes possessed lobulated nuclei and a large number of cytoplasmic granules, each of which was oval and contained electron-dense materials and a crystalloid. Type II granulocytes had small eccentric nuclei and were subdivided into IIa and IIb granulocytes by electron microscopic analysis. Granules of type IIa granulocytes were furnished with an electron-dense rim. Granules of type IIb granulocytes were larger than those of type IIa, containing randomly distributed electron-dense and electron-lucent materials. Type III granulocytes possessed round nuclei and a few large granules. The granules were filled with regularly arranged fibriform materials and some needle-like structures. Monocytes were morphologically similar to those of mammals.     

Pharmacokinetics and pharmacodynamic effects in koi carp (Cyprinus carpio) following immersion in propofol

Objective

To test the hypothesis that plasma propofol concentration (PPC) is associated with anesthetic effect in koi carp administered propofol by immersion.

Surgical removal of an ovarian tumour in a koi carp (Cyprinus carpio)

Ultrasonography, radiography and exploratory coeliotomy were used to diagnose and treat a large intracoelomic neoplasm from a female koi carp (Cyprinus carpio) presented for abdominal enlargement of several months duration. Feed was withheld for 1 week immediately prior to surgery and the fish was sedated with isoeugenol (AQUI-S) at a dose rate of 10 mL/L to facilitate diagnostic imaging techniques. Surgical anaesthesia was induced by adding tricaine (MS-222) 50 mg/L to the water and an exploratory coeliotomy and tumour removal was performed. The fish was allowed to recover in fresh water at 18 degrees C and salt was added slowly to the water over a period of 1 hour to a concentration of 5 g/L This concentration was maintained in a recovery pond for 1 week postoperatively. Enrofloxacin was administered intramuscularly (10 mg/kg) immediately, 3 days and 1 week postoperatively. A diagnosis of undifferentiated ovarian carcinoma was made on the basis of the histological appearance of the neoplasm and immunohistochemical staining.     

Papilloma and squamous cell carcinoma in koi carp (Cyprinus carpio).

Over a period of two years four ornamental koi carp (Cyprinus carpio) of one variety in a mixed population of 16 were affected with papillomas of the head and body. In one fish there was a transition of these tumours into a squamous cell carcinoma in the region of the head and posterior gill space, with deep invasion of the underlying bone. One of the fish recovered completely after the sloughing of the papillomas. In view of the progressive nature of the lesions, the condition was presumed to be due to an infectious agent, but transmission electron microscopy failed to reveal any virus particles.     

Comparative pharmacokinetics of norfloxacin nicotinate in common carp (Cyprinus carpio) and crucian carp (Carassius auratus) after oral administration

Comparative pharmacokinetics of norfloxacin nicotinate (NFXNT) was investigated in common carp (Cyprinus carpio) and crucian carp (Carassius auratus) after a single oral dose of 10 mg/kg body weight (b.w.). Analyses of plasma samples were performed using ultra‐performance liquid chromatography (UPLC) with fluorescence detection. After oral dose, plasma concentration–time curves of common carp and crucian carp were best described by a two‐compartment open model with first‐order absorption. The pharmacokinetic parameters of common carp were similar to those of crucian carp. The distribution half‐life (t_1/2α), elimination half‐life (t_1/2β), peak concentration (C_max), time‐to‐peak concentration (T_max), and area under the concentration–time curve (AUC) of common carp were 1.58 h, 26.33 h, 6069.79 μg/L, 1.08 h, and 103072.36 h·μg/L, respectively, and those corresponding to crucian carp were 1.36 h, 26.55 h, 9586.06 μg/L, 0.84 h, and 126604.4 h·μg/L, respectively. These studies demonstrated that 10 mg NFXNT/kg body weight in common carp and crucian carp following oral dose presented good pharmacokinetic characteristics.     

Blood changes in carp (Cyprinus carpio) induced by ulcerative Aeromonas salmonicida infections

Only recently Aeromonas salmonicida has been recognized as a significant bacterial pathogen in ulcerative disease of cyprinid fish. Our attempts to formulate a vaccine based on bacterial surface antigens were unsuccessful in conferring reliable protection against lethal challenge. This lead us to study pathological changes in the humoral defense system during ulcerative A. salmonicida infection in carp. High numbers of opportunist pathogens such as A. hydrophila and Pseudomonas sp. were frequently recovered from the internal organs of moribund fish, in addition to A. salmonicida. These findings together with leucopenia in moribund fish suggest that pathogenesis is characterized by a state of immune suppression. In addition, fish which had sustained a sublethal infection were not protected against a subsequent lethal challenge. However, fish previously injected with a concentrated and inactivated culture supernatant showed protection. Differential blood cell counts did not differ between experimental and control groups during sublethal infection in contrast to serum proteins. Furthermore infected non-immune carp showed a progressive decrease of immunoglobulin and total serum protein levels before the day of peak mortality whereas protected carp maintained the immunoglobulin concentration despite a decrease in protein. Our observations suggest the involvement of multiple pathogenic events, affecting different parts of the humoral defense system during ulcerative A. salmonicida infection. The immunosuppressive effects can be minimized by prior vaccination with culture supernatant.     

Identification of spring viraemia in carp (Cyprinus carpio L) in Great Britain.

An investigation into a mortality of carp revealed a virus which was identified serologically and morphologically as being identical to SVC virus. SVC is a serious disease of European carp farms and this is the first positive identification of this disease in Great Britain.     

Starvation-induced pathobiology in the gut of carp (Cyprinus carpio L.)

In order to assess the effects of starvation on intestinal intraepithelial lymphocytes (i-IEL) count and histological changes of the carp gut mucosa, one group of fish (n = 10) were fed commercially prepared standard diets and another group of fish (n = 10) were starved for 4 weeks. Carp starved for 4 weeks developed enteropathy, comprising folds atrophy, stratum compactum hyperplasia, significant periodic-acid-Schiff (PAS)-positive (P < 0.00001), but not Alcian blue (ALB)-positive, goblet cell (GC) hyperplasia and a significant decrease (P < 0.00001) in i-IEL numbers. These changes were associated with a dense cellular infiltrate into the lamina propria. Taken together, these data suggest that the pathobiology of starvation-induced i-IELs decrease, matching PAS-positive goblet cell proliferation and inflammatory cells homing to the gut, could be classified as a non-infectious enteropathy induced by starvation.     

Massive mortality of common carp (Cyprinus carpio carpio) in the St. Lawrence River in 2001: diagnostic investigation and experimental induction of lymphocytic encephalitis

A massive fish kill affecting exclusively common carp (Cyprinus carpio carpio) in the St. Lawrence River, Québec, Canada, during the summer of 2001 was investigated by use of laboratory diagnostic methods and by an attempt to experimentally induce the disease. The ultimate causes of mortality were opportunistic bacterial infections with Aeromonas hydrophila and Flavobacterium sp. secondary to immunosuppression induced by physiologic (i.e., spawning) and environmental (i.e., high temperatures and low water levels) stressors, and possibly enhanced by an infection causing lymphocytic encephalitis observed in 9 of 18 (50%) fish examined. Experimental induction of disease was attempted in captured wild carp by administration of crude and filtered (particulate <0.22 microm) inocula prepared from a homogenate of tissues from carp affected by the natural outbreak. Although significant clinical disease or mortality was not induced by experimental challenge, lymphocytic encephalitis similar to the one observed in naturally affected carp was induced in four of seven (57%) fish administered crude inoculum and four of seven (57%) fish administered filtered inoculum. None of the control fish inoculated with sterile phosphate-buffered saline (n = 6) were affected by encephalitis. The cause of the encephalitis observed in carp from the natural outbreak and in experimentally inoculated fish could not be determined by use of virus isolation and transmission electron microscopy.     

Comparative pharmacokinetics and tissue distribution of quinocetone in crucian carp (Carassius auratus), common carp (Cyprinus carpio L.), and grass carp (Ctenopharyngodon idella) following the same experimental conditions

The pharmacokinetics and tissue distribution of quinocetone (QCT) in crucian carp (Carassius auratus), common carp (Cyprinus carpio L.), and grass carp (Ctenopharyngodon idella) were compared after oral administration of QCT (50 mg/kg body weight) at water temperature of 24 ± 1 °C. Similar QCT plasma concentration–time profiles were found in the three species of cyprinid fish at the same dosage regimen and water temperature, which were all fitted two‐compartment open pharmacokinetic model. However, different pharmacokinetic parameters were observed in crucian carp, common carp, and grass carp. The absorption rate constants (K_a) of QCT were 1.65, 1.40 and 1.74/h, respectively and absorption half‐lives (t_1/2kα) were 0.42, 0.49, and 0.40/h, respectively. The distribution half‐life (t_1/2α) was 2.83, 0.67, and 0.88 h, respectively, and elimination half‐lives (t_1/2β) of QCT were 133.97, 63.55, and 40.76 h, respectively. The maximum concentrations (C_max) of QCT in plasma were 0.315, 0.182, and 0.139 μg/mL and the time to peak concentrations (T_p) were 1.45, 0.96, and 1.08 h, respectively. The area under the plasma concentration‐time curves (AUC) were 12.35, 5.99, and 4.52 μg·h/mL, respectively. The distribution volumes (V_d/F) of QCT were calculated as 117.81, 128.71, and 220.10 L/kg, respectively. The tissue analysis showed that a similar regularity was obtained in the three species of cyprinids with a single dose of 50 mg/kg body weight after oral administration at the same water temperature. The tissue concentration of QCT in each fish was in order of liver>kidney>muscle, while the residues of QCT in the three species of cyprinid fish were in order of crucian carp>common carp>grass carp.