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).     

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.     

Induction of specific cytotoxic T-cell activity against xenogeneic target cells in carp (Cyprinus carpio)

OBJECTIVE: To investigate the induction of cytotoxic T cells in carp (Cyprinus carpio) after inoculation of fish with 2 xenogeneic line cells and to examine specificity of the cytotoxic activity. ANIMALS: 22 carp. PROCEDURE: Fish were inoculated with mouse myeloma line cells P3.NS-1/1Ag4.1 (NS-1) or chicken Marek's disease tumor-derived lymphoma line cells (MDCC MSB-1). Cytotoxic activity of immune lymphocytes was evaluated by incubating effector cells with homologous and heterologous target cells. Populations of effector cells were identified by blocking T-lymphocytes from effector cells, using anti-carp T-cell monoclonal antibody and complement. RESULTS: Lymphocytes in blood, spleen, and head kidney of carp inoculated with NS-1 cells or MDCC MSB-1 cells had dose-dependent cytotoxic effects against homologous target cells but not against heterologous target cells. Lymphocytes from noninoculated carp did not have cytotoxic effects. Depletion of T-lymphocytes in spleen cells from NS-1-inoculated carp resulted in a decrease of cytotoxic activity against NS-1 cells. Cytotoxic activity of spleen lymphocytes from NS-1-inoculated or noninoculated carp was not evident when cytotoxic tests were performed after addition of anti-NS-1 carp serum. CONCLUSIONS AND CLINICAL RELEVANCE: Inoculation with xenogeneic target cells induces a specific cytotoxic T-cell response in carp. Thus, cell-mediated immunity plays a role in defense against infection of parasitic organisms such as protozoa and helminths.     

Immunosuppression of carp (Cyprinus carpio L.) to ichthyophthiriasis using the corticosteroid triamcinolone acetonide

The immune response of juvenile mirror carp (Cyprinus carpio L.) has been investigated in relation to protective immunity and immunosuppression to the disease ichthyophthiriasis. Protective immunity was induced by exposing juvenile carp to approximately 2,000 theronts per fish for 3 hours at a concentration of approximately 80 theronts cm-3 in dechlorinated water pH 7.0-7.2, 20 +/- 2 degrees C in the dark, on three separate occasions of 14 day intervals. Following each exposure, re-infection was prevented by transferring fish to clean aquaria twice daily from day 5-10. Fish were challenged 4 weeks following exposure to the third immunising infection with a potentially lethal dose of approximately 8,000 theronts per fish for 3 hours at a concentration of approximately 320 theronts cm-3. All immunised fish survived although 19% showed initial signs of invasion, the parasites in these instances being confined to periphery of fins. Mortalities of 100% were recorded in non-immunised controls, first deaths occurring 5 days after challenge. Fourteen days following challenge, immune fish received one of the following treatments; intraperitoneal injection of the corticosteroid triamcinolone acetonide at a dose of 200 micrograms g-1 body weight, intraperitoneal injection of 0.85% saline or left untreated; non-immunised fish were subjected to similar procedures. On challenge 6 days later, all fish developed heavy infection with up to 100% mortalities with the exception of immunised fish administered saline or left untreated. Repeat experiments gave comparable results. The results indicate that immunosuppression can be induced by administration of high levels of synthetic corticosteroid.(ABSTRACT TRUNCATED AT 250 WORDS)     

饲料中不同脂肪源对鲤鱼生长性能、脂质代谢和抗氧化能力的影响

在一种实用饲料配方的基础上,分别添加1.5％的鱼油、豆油、菜籽油、亚麻籽油和猪油作为单一脂肪源,配制成5种等氮等能(粗蛋白质含量35％,总能15mJ/kg)的试验饲料,通过8周的饲养试验,以研究饲料中不同脂肪源对鲤鱼生长性能、体组成、肝胰脏脂质代谢相关酶和抗氧化酶活性的影响.选取平均初重为(5.83±0.01)g的鲤鱼750尾,随机分成5组,每组3个重复,每个重复50尾鱼.结果表明:特定生长率(SGR)、蛋白质效率(PER)、饲料系数(FCR)以鱼油组最好,猪油组最差,且2组间存在显著差异(P＜0.05).SGR、PER和FCR在豆油组、菜籽油组、亚麻籽油组间无显著差异(P＞0.05).不同脂肪源对全鱼粗蛋白质和粗脂肪含量有显著影响(P＜0.05),但对全鱼干物质和粗灰分含量无显著影响(P＞0.05).鱼油组全鱼粗蛋白质含量最高,而粗脂肪含量最低.肝胰脏脂蛋白脂酶(LPL)活性以鱼油组最高,其次是豆油组、菜籽油组、亚麻籽油组,以猪油组最低.肝胰脏苹果酸脱氢酶(mDH)活性表现为:亚麻籽油组＞豆油组＞鱼油组＞菜籽油组＞猪油组.猪油组肝胰脏超氧化物歧化酶(SOD)活性显著低于其他各组(P＜0.05),而其他各组间差异不显著(P＞0.05).不同脂肪源对肝胰脏总抗氧化能力(T-AOC)有显著影响(P＜0.05),以鱼油组最高,猪油组最低.由此可见,鱼油是鲤鱼较适宜的脂肪源,而猪油不适宜作为鲤鱼的单一脂肪源,会损害肝胰脏健康,进而影响鱼体生长.     

Protection against atypical Aeromonas salmonicida infection in carp (Cyprinus carpio L.) by oral administration of humus extract

Humic substances are formed during the decomposition of organic matter in humus, and are found in many natural environments in which organic materials and microorganisms have been present. In the present study, oral administration of humus extract to common carp (Cyprinus carpio L.) induced effective protection against experimental atypical Aeromonas salmonicida infection. Mortality of fish and development of skin lesions such as hemorrhages and ulcers were significantly suppressed in carp treated with 10%, 5% or 1% humus extract adsorbed on dry feeding pellets. The median surviving days was also greater in fish treated with 10% or 5% humus extract than in untreated fish. Atypical A. salmonicida was isolated from ulcerative lesions of part of dead fish, but Aeromonas hydrophila and Flavobacterium sp. were also isolated from these fish, verifying bacterial population changes during the progression of skin lesions. These results clearly show that treatment of fish with humus extract is effective in preventing A. salmonicida disease.     

Experimental transmission of turkey viral hepatitis to day-old poults and identification of associated viral particles resembling picornaviruses.

Turkey viral hepatitis (TVH) was experimentally reproduced in two experiments in 1-day-old poults. In the first experiment, an infectious inoculum was prepared from filtered yolk materials harvested from dead embryonating chicken eggs (ECE) previously inoculated with suspensions of liver and pancreas tissues collected from TVH-affected birds in commercial turkey flocks. One-day-old poults given a yolk-sac inoculation or oral gavage with this preparation developed lesions in the liver and pancreas characteristic of TVH at 20 days postinoculation (PI) in 60% and 14% of the experimentally infected birds, respectively. With the identical inoculum, embryo mortality occurred at 8 and 10 days PI in embryonating turkey eggs (ETE) inoculated into the yolk sac. In the second experiment, an infectious inoculum was prepared from filtered yolk materials from dead ETE harvested in the first experiment. One-day-old poults given a yolk-sac inoculation with this filtered yolk material developed lesions in the liver and pancreas within 5 days PI. At 20 days PI, 67% of the experimentally infected birds had similar lesions. With the inoculum given to these poults, embryo mortality occurred at 6, 8, and 10 days PI in ETE inoculated into the yolk sac. Virus particles 26-28 nm in diameter with icosahedral morphology typical of picornaviruses were identified by EM in the yolk sacs of ETE that died in both experiments, and inoculated ETE that died following passage of filtered suspensions of pancreatic tissues collected from affected birds in the first experiment.     

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.     

Reproductive medicine in koi (Cyprinus carpio).

Each year more veterinarians are seeing ornamental fish patients and our knowledge of how to manage the pet fish patient is increasing at a rapid pace. A large percentage of these patients are nishikigoi (Cyprinus carpio) which are taxonomically an ornamental carp. In this country and in many parts of the world we refer to these fish as koi. Reproductive medicine problems are well documented in koi and a thorough knowledge of this subject will aid the fish practitioner in diagnosis and treatment.     

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.     

Effects of direct immersion in antigen on immunological memory in young carp, Cyprinus carpio

The study asks whether, in fish, antigens encountered early in life can prime the immune system to yield memory responses on subsequent challenge with the same antigen and, if so, whether positive immunity or immunological tolerance is induced. The direct immersion method of vaccination was used to prime 4 week old carp, Cyprinus carpio, and was compared with priming by injection. Three different forms of antigen were used: the thymus dependent antigen, human gamma globulin (HGG) in soluble and in particulate (latex bound) form; also the putative thymus independent bacterin, formalin-killed Aeromonas salmonicida. The thymus dependent antigens were also used on 9 month old animals. In 4 week old carp, A. salmonicida vaccine delivered either by direct immersion or intraperitoneally (i.p.) yielded enhanced serum antibody levels and heightened proliferative responses in the lymphoid tissue of the spleen and kidney. Latex-bound HGG applied by direct immersion was found to partially suppress secondary antibody production while still eliciting enhanced proliferation. The decrease in antibody production following direct immersion priming of young fish with latex-bound HGG was not nearly as marked as the tolerance induced following priming with latex-bound HGG by the i.p. route and, unlike the tolerance induced by the injection route, may possibly still occur in older fish. When HGG was applied to young carp in soluble form by direct immersion it was ineffective and failed to influence memory induction. This is in contrast to the antibody tolerance, accompanied by an enhanced proliferative response following challenge, which resulted from administration of the soluble antigen by injection in the young fish. The status of the immune system in these antibody-tolerant fish is still far from clear. This highlights the need for further investigation of the role of cell-mediated reactions and local immunity in the immune responses of fish.     

Protection against atypical Aeromonas salmonicida infection in common carp, Cyprinus carpio L., by oral administration of a mixed microbial culture of Lactobacillus paracasei, Pichia membranifaciens and Saccharomyces cereviciae

A microbial culture was prepared by co-cultivation of Lactobacillus paracasei, Pichia membranifaciens and Saccharomyces cereviciae for 48 hr at 30°C in rice bran extract medium, supplemented with dextrose. Oral administration of the resulting non-viable heat-inactivated microbial culture to common carp, Cyprinus carpio L., delivered in feed for four weeks, induced effective protection against experimental atypical Aeromonas salmonicida infection which causes "ulcer disease". After challenge of the carp by immersion, fish mortality and development of skin lesions such as hemorrhages and ulcers were significantly suppressed in carp treated with mixed microbial culture adsorbed on dry pellets relative to carp treated with medium or without extract. Atypical A. salmonicida was re-isolated from ulcerative lesions in parts of dead and surviving fish, but Aeromonas hydrophila and Flavobacterium sp. were also isolated from these fish, verifying microbial population changes during the progression of skin lesions. Among interleukin-1β (IL-1β), tumor necrosis factor-α, as well as CXC-α and CXC-β chemokines, gene expression of IL-1β was up regulated in the spleen and head kidney three weeks after administration of the mixed microbial culture. These results clearly show that this mixed microbial culture, delivered in feed, is effective in preventing A. salmonicida disease in carp.     

Ulcerative skin disease in a group of koi carp (Cyprinus carpio).

A case report detailing the presenting clinical signs, diagnostics, and treatment of ulcerative skin disease in a group of koi carp (Cyprinus carpio) is presented.     

Yersinia ruckeri septicaemia in experimentally infected carp (Cyprinus carpio L.) fingerlings.

The presence of Yersinia ruckeri, the causal agent of enteric redmouth disease (ERM) in salmonids and a few other freshwater fish, has so far been reported from a variety of sources including the intestine of healthy carp. Since there are no data on the pathogenicity of this bacterium for carp, 15 fingerlings were experimentally infected by intraperitoneal injection of about 5 x 10(5) cells. Thirteen injected fish were moribund or died within 4 days with septicaemic lesions. Two survivors were sampled on Day 28 after infection. Yersinia ruckeri was reisolated from the internal organs of all experimental fish. By histopathological examination moribund fish had generalised bacteriaemia with inflammation, degeneration and necrotic foci in kidney, liver and spleen, corresponding to findings described previously in ERM of rainbow trout. Survivors of challenge on Day 28 had a chronic disease characterised by prominent peritonitis and enteritis, exhaustion of the erythroid, granuloid and lymphoid components in haematopoietic kidney tissue as well as focal degeneration and necrosis in organs. These data indicate a high sensitivity of carp to intraperitoneal infection with a relatively low dose of Y. ruckeri.     

Assessment of ovulation of common carp (Cyprinus carpio) females selected for induced spawning on the basis of external morphological characteristics

Secondary sexual characteristics such as softening and rounding of the abdomen as well as reddening and protrusion of the anal papilla and vent can be of help to breeders in selecting common carp (Cyprinus carpio) females prepared for propagation. To assess the reliability of this method, long-term data obtained on induced spawning of common carp at a large-scale fish hatchery were evaluated. The average spawning ratio of 2,620 females receiving hormonal injections was 79.8%. The average pseudogonadosomatic index (PGSI) calculated from data on the egg production of 2,086 females was 16.3 +/- 5.87% (mean +/- SD) for the same period. There was a correlation between fish weight and the time of induction determined by the breeder on the basis of external morphological characteristics. The similarity of the responses of females, including both spawning ratio and PGSI, among the different weight categories proved the reliability of this method for identification.     

Genetic resistance of carp (Cyprinus carpio L.) to Trypanoplasma borreli: influence of transferrin polymorphisms

In serum most of the iron molecules are bound to transferrin (Tf), which is a highly polymorphic protein in fish. Tf is an essential growth factor for mammalian trypanosomes. We performed a series of experiments with Trypanoplasma borreli to detect putative correlations between different Tf genotypes of common carp (Cyprinus carpio L.) and susceptibility to this blood parasite. Five genetically different, commercially exploited carp lines (Israelian 'D', Polish 'R2' and 'K', Ukrainian 'Ur', Hungarian 'R0') and a reference laboratory cross ('R3xR8') were challenged with T. borreli and parasitaemia measured to determine susceptibility to the parasite. Among the commercial carp lines, Israelian 'D' carp were identified as most and Polish 'R2' carp as least susceptible, and used to produce a next generation and reciprocal crosses. These progenies were challenged with T. borreli and parasitaemia measured. We demonstrated significant effects of genetic background of the carp lines on susceptibility to T. borreli. This genetic effect was preserved in a next generation. We also observed a significant male effect on susceptibility to T. borreli in the reciprocal crosses. Serum samples from a representative number of fish from two infection experiments were used for Tf genotyping by polyacrylamide gel electrophoresis (PAGE), identifying DD, DG and DF as most frequent Tf genotypes. We could detect a significant association of the homozygous DD genotype with low parasitaemia in the least susceptible 'R2' (and 'K') carp lines and the lack of a such an association in the most susceptible 'D' carp line. Upon examination of parasite growth in vitro in culture media supplemented with 3% serum taken from fish with different Tf genotypes, we could show a faster decrease in number of parasites in culture media with serum from DD-typed animals.     

Granulocyte responses to experimental injection of live and formalin-killed bacteria in carp (Cyprinus carpio)

The objective of the study was to investigate the dynamics of changes in number of granulocytes in bacterial infections of carp (Cyprinus carpio). Carp were inoculated with non-pathogenic or pathogenic bacteria and changes in type I (neutrophils) and type II granulocyte (basophils/eosinophils) counts in kidney, circulating blood and peritoneal cavity were assessed. After the injection of non-pathogenic bacteria (Escherichia coli), the number of type I and II cells in blood increased after 6-12h, but returned to the control level after 24-48 h. In contrast, after the injection of pathogenic bacteria (Aeromonas hydrophila), the number of type I cells initially increased followed by an increase in the number of type II cells. The peak counts of type I and II cells were at 12 and 24h after the injection, respectively. When the fish were given serial-injections of formalin-killed bacteria at 12-h intervals, the type II cells also predominantly increased and remained at high levels, following the peak count of type I cells.     

框镜鲤嗜水气单胞菌的分离鉴定

以患病濒死的框镜鲤为材料,得到1株细菌,动物回归试验证明其具有较强的致病性,然后对病原菌的形态学、培养特性、理化特性、16SrRNA序列分析等生物学特性进行了鉴定与分析。结果表明,该菌株为嗜水气单胞菌。     

Gonadosomatic index and testis morphology of common carp (Cyprinus carpio) in rivers contaminated with estrogenic chemicals

To study the effect of estrogenic chemicals on fish, the gonadosomatic index (GSI = [testis weight/body weight] x 100) and testis histology of mature common carp (Cyprinus carpio) from 2 contaminated sites (Ishizu and Wada rivers, Osaka) and a control site were examined between June 1998 and March 2001. The concentration of nonylphenol, bisphenol A and 17beta-estradiol in the Ishizu river was 3-4 times higher than in the Wada river. In the pre-breeding and breeding seasons, there were no significant differences in body weight among carp from the 3 sites, the body weight of Ishizu river carp being significantly lower (p<0.05) than that of Wada river fish only in the post-breeding season. The GSI and testis weight in fish from the Ishizu river were significantly lower (p<0.05) than in control fish during all phases of gonadal cycle and lower than in Wada river fish in the pre-breeding and post-breeding season. No histological abnormalities were found in the testes of the males examined. Histological observation of the testes revealed a delay in the onset of spermatogenesis in fish from the Ishizu river compared with those from the other sites. These results clearly imply that the estrogenic chemicals in the Ishizu river adversely affect the testis development of the fish.     

Functional changes of the LH-immunoreactive cells in adenohypophysis of the common carp (Cyprinus carpio) from rivers contaminated with estrogenic chemicals

The adverse effect of estrogenic chemicals on luteinizing hormone-immunoreactive (LH-ir) cells in the adenohypophysis of common carp (Cyprinus carpio) was examined using immunocytochemical and morphometric methods. Adult male fish were collected from two contaminated sites (Ishizu and Wada Rivers) and from a control pond at Agriculture, Food and Environmental Sciences, Research Center of Osaka Prefecture. The concentration of nonylphenol, bisphenol A and 17beta-estradiol in the Ishizu River was 3-4 times higher than that in the Wada River. The proportion and size of LH-ir cells were evaluated using the point-counting method by optical microscopy. In control carp, the proportion of LH-ir cells in the breeding season was significantly lower than in the pre- and post-breeding seasons. The same tendency was also found in Ishizu and Wada River carp, but without statistical significance. The proportion of LH-ir cells in Ishizu River carp was significantly lower than that of the control and the Wada River in all seasons. The LH-ir cells in control carp increased in size in the breeding season. LH-ir cells in Ishizu River carp were significantly (p<0.05) smaller than those in control fish, but not different from Wada River carp. A disturbance in the secretory function of LH-ir cells was found in carp from the Ishizu River; granulation and vacuolation were not in synchronization with those of control and Wada River fish. Our data suggest that the estrogenic chemicals in the Ishizu River interfere with functions of LH-ir cells directly or through the testis.