The histopathology of carp, Cyprinus carpio L., exposed to microcystins by gavage, immersion and intraperitoneal administration

Carp liver, gills, intestine, kidneys, heart and spleen were studied by histology after the fish were exposed to microcystins by gavage, immersion and intraperitoneal administration. Intraperitoneal inoculation with microcystins caused necrosis or dose- dependent degeneration in the liver, gills and kidneys. Gavaging with microcystins caused changes in the histopathology of the liver and gills. Cellular degeneration and necrosis occurred in the liver, gills and kidneys when carp were introduced to a tank containing 1.7 μg ml^?1 of microcystins. Lesions were not observed in the heart, spleen or intestines from any of the treated carp. Microcystins administered by intraperitoneal injection at a concentration of 50 μg kg^?1 were lethal to all fish within 8 h, while gavaging with 250 μg kg^?1 of microcystins caused minimal damage in the tissues studied.     

Pharmacokinetics and tissue distribution of oxytetracycline in carp, Cyprinus carpio L., following different routes of administration

Abstract. The objective of this pharmacokinetic study was to investigate absorption, distribution, elimination and bioavailability of oxytetracycline (OTC) in carp, Cyprinus carpio L ., after different routes of administration, OTC was administered intravenously (i.v.), intramuscularly (i.m.) and orally at 60 mg/kg body weight. OTC levels were determined in plasma and several tissues. Analysis of the plasma drug concentration-time curves following i.v. OTC injection revealed three distinct phases. A three-compartment open model was used to derive pharmacokinetic parameters. Compared to mammals, a very extended final elimination half-life was observed (139.8±38.1 h). Following i.m. OTC administration, C_max was 56.8±10.9μg OTC/ml at 14 h post-injection. The Vd area was 2.1 ± 0.66 1/kg. Extreme differences were observed with respect to bioavailability following i.m. and oral administration; approximately 80 and 0.6%, respectively. Following i.m. injection tissue OTC determinations revealed that the drug was accumulating in pronephros, bone tissue and scales. After 21 days the OTC concentrations were 2.9±0.8, 5.2±0.3 and 4.7±3.1 μg/ ml, respectively. In tissue samples from the dorsal region (muscle), including the injection site, OTC could not be demonstrated at that time. The pharmacokinetic data are discussed in relation to the susceptibility of the immune system of fish for modulation.     

洛美沙星在鲤鱼体内的药物动力学及残留

用高效液相色谱 (HPLC)测定方法研究洛美沙星在鲤鱼 (Cyprinuscarpio)体内的药物动力学和残留。洛美沙星以 2 0mg/kg体重单剂量口灌鲤鱼后 ,测定其血浆药物浓度 ,最低检测限为 0 0 5 μg/mL ,动力学模型符合开放性有吸收二室模型 ,药物动力学参数 :表观分布容积 (Vd/F)、吸收半衰期 (tl/ 2kα)、分布半衰期 (t1/ 2α)以及消除半衰期 (t1/ 2 β)分别为 5 2 1L/kg、 0 31h、 1 0 2h、 2 0 0 3h ,其药时曲线下面积(AUC)为 110 92 μg·h/mL。以相同剂量单次口灌鲤鱼后 ,在不同的天数测定了鲤鱼皮肤、肌肉和肝胰脏中洛美沙星的残留 ,在给药 12天后 ,洛美沙星在各组织中均能检测到且残留均低于 0 0 8μg/g ,结果表明洛美沙星在鲤鱼体内消除缓慢、残留期较长 ,休药期不低于 12天。     

Enhancement of resistance to bacterial infection in rainbow trout, Oncorhynchus mykiss (Walbaum), by oral administration of bovine lactoferrin

Abstract Bovine lactoferrin was evaluated for its ability to enhance resistance of rainbow trout, Oncorhynchus mykiss (Walbaum), to infection with Vibrio anguillarum. Oral administration of lactoferrin (100 mg kg⁻¹) to fish daily for 3 days prior to an intraperitoneal challenge with V. anguillarum resulted in increased survival rates, and enhanced resistance against Streptococcus sp., although to a lesser extent. In lactoferrin-treated fish, an increase in phagocytic and chemiluminescent (CL) activities of pronephros cells against V. anguillarum was observed. The phagocytic and CL activities of cells against Streptococcus sp. were also significantly increased. However, no in vitro bactericidal activities of lactoferrin against V. anguillarum or Streptococcus sp. were observed. This suggests that the lactoferrin enhanced the resistance of the rainbow trout against bacterial infection through the activation of phagocytes.     

Antibody response of two populations of common carp, Cyprinus carpio L., exposed to koi herpesvirus

Common carp, Cyprinus carpio L., exposed to koi herpesvirus (KHV) may become persistently infected and populations containing such virus-infected individuals may transmit the virus to other fish when co-habited. Detection of virus-infected fish in a population is thus critical to surveillance and control programmes for KHV. A study was therefore designed to detect anti-KHV serum antibodies, with an enzyme-linked immunosorbent assay, in common carp following experimental exposures to KHV under varying environmental conditions. The study determined that a proportion of fish within a population experimentally exposed to KHV (at least 10–25%) develop high antibody titres (1/1600 or greater) to the virus, and this immunological response was detectable for several months (observed at the termination of the experiments at 65, 46 and 27 weeks post-exposure). Furthermore, this response was detected in one population of fish that did not succumb to a high level of mortality when maintained at water temperatures that were non-permissive for KHV. Elevating the water temperatures to permissive conditions for KHV resulted in recurrence of disease despite the presence of anti-virus antibodies, suggesting that serum antibodies alone are not protective under the conditions of our trials.     

Urine properties in carp, Cyprinus carpio L., with sekoke disease

Abstract. Changes in the properties of urine and blood of carp with sekoke disease were studied. With the progress of this disease, the parameters of blood and particularly urine changed significantly. After 120 days, urine flow, osmolarity and concentrations of inorganic ions (K⁺, Ca²⁺, Mg²⁺, Cl⁻) and organic compounds (ammonium, creatine and creatinine, protein, glucose) in the experimental group showed higher values than those of the controls. Even after 60 days, when clinical signs of sekoke disease were not evident, abnormally high concentrations of ammonium, protein and glucose in the urine were found in the experimental group.     

Detection of koi herpesvirus in common carp, Cyprinus carpio L., by loop-mediated isothermal amplification

Loop-mediated isothermal amplification (LAMP) is a novel method that amplifies DNA with high specificity and rapidity under isothermal conditions. In this study, using the LAMP method, a protocol for koi herpes virus (KHV) detection in common carp was designed. A set of four primers, two inner and two outer, were designed based on the sequence of the thymidine kinase (tk) gene of KHV. Time and temperature conditions for detection of KHV were optimized for 60 min at 65 degrees C. The detection limit using LAMP was found to be similar to that by polymerase chain reaction. In this study, we have developed a highly sensitive and rapid diagnostic procedure for detection of KHV infection in common carp.     

Polysaccharide-induced protection of carp, Cyprinus carpio L., against bacterial infection

Abstract. The efficacy of 10 polysaccharides (curdlan, inulin, krestin, laminaran, lentinan, levan, schizophylian, selerogiucan, yeast glucan and zymosan) to enhance protection of carp, Cyprinus carpio L., against bacterial infection was investigated. Carp were intraperitoneally injected with the polysaceharides (2–l0 mgkg^-1) on days 1 and 4, and challenged with Edwardsiella tarda on day 7. Among the polysaccharides tested, lentinan, schizophyllan and scleroglucan, which are l,6-branchcd-β-l,3-glucans, significantly increased the survival rate. They also induced a protective effect against Aeromonas hydrophila at a dose of 5 mg kg^-1. The ability of the polysaccharides to activate the alternative complement pathway (ACP) was examined by incubating the polysaccharides with carp serum and measuring the residual ACP activity. At a final concentration of 0.l mgml^-1, l,6-branched-β-1,3-glucans greatly reduced (76–77%) the ACP activity. Therefore, it is suggested that the protective effect of the l,6-branched-β-1,3-glucans may be associated with the activation of ACP.     

Responses of fingerling carp, Cyprinus carpio L., to dietary lysine

Abstract. The lysine requirements of fingerling carp, Cyprinus carpio L., for optimum growth and efficiency of food utilization were determined in two experiments by the addition of graded supplements of lysine to a basal diet deficient in this amino acid.
The lysine requirement was estimated to be around 14.5 g/kg dry matter at an ambient temperature of 20°C. At 25°C continuing growth responses occurred up to a dietary lysine concentration of 22.4 g/kg DM. However, when these responses are considered in relation to daily lysine intake, the gross efficiency of utilization of dietary lysine for growth appeared to be unaffected by environmental temperature.
Dietary lysine concentrations exerted no consistent effect upon carcass composition of carp. However, fat deposition tended to increase as food intakes increased in response to lysine additions or to elevated ambient temperature.     

Analysis of angling vulnerability of common carp, Cyprinus carp/0 L., in catch-and-release angling in ponds

Abstract. The vulnerability of common carp to angling was studied in a drainable pond of 0–4 ha, stocked near the carrying capacity (700 kg/ha) with known numbers of individually marked carp. The numbers of carp hooked and landed ('caught') by each angler were registered during a period of one month. Landed carp were checked for marks. All carp were returned to the pond. The catch results were analysed with use of a simulation model of a pond fishery. The observed catch and recapture frequencies were compared with the expected values. It was shown that the vulnerability of carp to hooking decreased after one experience with a fish hook. Differences in decreased vulnerability to hooking were found within the carp population. This resulted in unequal recapture sequences for the various groups in the population. Analysis of the growth of carp and the capture data indicated that under the experimental conditions of high stocking density, carp that were more vulnerable to angling showed better growth than carp that avoided the hook after a hook experience. The experiments showed that the decreased vulnerability to the fish hook disappeared when the population was not angled for about one year. The carp acquired the hook avoidance behaviour again after one experience with a hook.     

Differences in resistance of carp, Cyprinus carpio L., to atypical Aeromonas salmonicida

Abstract. The degree of resistance to an atypical strain of Aeromonas salmonicida , the causative bacterium of carp erythrodermatitis, was examined in two strains of carp, Cyprinus carpio L.: a Polish line. R3, sixth generation of conventional inbreeding (full-sib matings); and a Hungarian line. R8, fifth generation of conventional inbreeding. Comparisons were made between and within the two strains. Results showed a significant difference ( P < 0·001) in the degree of resistance, with the Hungarian carp showing greater resistance than the Polish carp. Differences within each strain were also observed indicating a maternal influence on resistance. Two transferrin genotypes in three genetic combinations were identified (DD, DG, GG) but were not found to influence resistance.     

Testing of performance in common carp Cyprinus carpio L. under pond husbandry conditions I: top-crossing with Northern mirror carp

Performance tests of Northern mirror carp (M72) and three different crossbreds were conducted in semi‐intensive pond conditions from the larval stage up to market size. The aim of this study was to evaluate the possible utilization of new hybrid combinations (M72 × PL – Poho?elice mirror carp) and (M72 × Dor – Israeli mirror carp), and to compare them with a hybrid widely reared as a commercial product (M72 × M2 – Hungarian mirror carp) and with M72 purebred. The testing model was derived from similar studies carried out in the conditions of the Czech Republic, where an internal control of different scale cover is used to eliminate all non‐genetic effects. ancova revealed at market size significantly better growth in M72 × Dor (1 619±28.3 g; LS mean±SE) and M72 × PL (1475±29.8 g) compared with M72 (1278±26.3 g). Survival during the test of 3 years duration was significantly the best in the M72 × Dor hybrid as were the dressing out parameters measured at market size, even if these were significantly different only in proportion of fillets with skin (39.1±0.28%). Interestingly, the crossbred M72 × M2 commonly used by Czech fishermen showed for both, growth (1371±26.2 g) and survival, the lowest values among crossbreds and with regard to dressing out parameters mostly among all tested groups.     

Ultrastructural studies on intestinal response of carp, Cyprinus carpio L., to the pseudophyllidean tapeworm, Bothriocephalus acheilognathi Yamaguti, 1934

Abstract. The pathological effects of Bothriocephalus acheilognathi on the gut of experimentally infected carp, Cyprinus carpio L., have been studied. Light and electron microscopical observations revealed that damage to the host gut was not restricted to the area engulfed by the bothria, and loss of gut microvilli and the separation and shedding of enterocytes occurred against the site of attachment. Lymphocytes, macrophages and eosinophils accumulated in the wall of the infected gut and migrated into the lumen where they adhered to the parasite tegument. The role of parasite-derived and host-produced factors in leucocyte migration and attachment to the worm are discussed.     

Koi herpesvirus epizootic in cultured carp and koi, Cyprinus carpio L., in Taiwan

Koi herpesvirus (KHV) poses a significant threat to cultured koi and common carp, both Cyprinus carpio L. Since the first reported case in Israel in 1998, KHV has rapidly spread worldwide. This study investigates the spread of KHV to Taiwan by collecting 49 cases of suspected common carp and koi infections from 2003 to 2005 for analysis. Clinical signs included lethargy, anorexia, increased respiratory movements and uncoordinated swimming. Hyperaemia, haemorrhage on body surface and necrotic gill filaments were recorded. Gill epithelial hyperplasia, necrosis and eosinophilic intranuclear inclusion bodies were observed by histological examination, while virions were detected using transmission electron microscopy. By detecting the presence of the KHV thymidine kinase (TK) gene and the KHV 9/5 gene using polymerase chain reaction (PCR), 37 cases were identified as KHV-positive, and the cumulative mortality of infected fish was 70-100%. Positive cases showed identical sequences for the genes analysed, implying that they were of the same origin. For the KHV 9/5 gene sequence, these cases exhibited 100% identity with the Japanese strain (TUMST1, accession number AP008984) and 99% identity with the Israeli (KHV-I, DQ177346) and US (KHV-U, DQ657948) strains. Additionally, a loop-mediated isothermal amplification (LAMP) assay was performed and found to be more sensitive than PCR tests, suggesting its potential use as a rapid diagnostic method for KHV. This is the first epidemiological study of KHV infection in cultured common carp and koi in Taiwan.     

Protection of common carp (Cyprinus carpio L.) spermatozoa motility under oxidative stress by antioxidants and seminal plasma

The protective influence of seminal plasma and the antioxidants catalase (CAT), superoxide dismutase (SOD), and glutathione (GTH) on quality parameters, oxidative stress indices, and antioxidant activity was studied in common carp (Cyprinus carpio) spermatozoa exposed to the xanthine–xanthine oxidase (X–XO) system. Fish spermatozoa were incubated for 5 and 20 min at 4 °C with X–XO concentrations of 1 mM X–0.1 U/mL, 0.6 mM X–0.05 U/mL, 0.3 mM X–0.025 U/mL, and 0.1 mM X–0.0125 U/mL. A dose-dependent reduction in spermatozoa motility and velocity was observed at concentrations of 0.1 mM X–0.0125 U/mL to 1 mM X–0.1 U/mL XO. Increase in spermatozoa motility parameters was recorded following treatment with antioxidants and seminal plasma. The level of the oxidative stress indices lipid peroxidation (LPO) and carbonyl derivatives of proteins (CP) was significantly reduced after addition of CAT, SOD, or GTH along with seminal plasma. Significant differences in SOD, glutathione reductase, and glutathione peroxidase activity were seen in spermatozoa incubated with, compared to that without, seminal plasma at all studied X–XO concentrations. The data demonstrated that CAT, SOD, or GTH in combination with SP can reduce reactive oxygen species stress in fish spermatozoa and improve spermatozoa quality.     

Effect of dietary l-tryptophan on osmotic stress tolerance in common carp, Cyprinus carpio, juveniles

Common carp juveniles were fed two types of diet (control: 0.1% tryptophan and TRP: 0.6% tryptophan) over 15 days. Thereafter, both groups were directly subjected to osmotic challenge (from 0 to 10 ppt) for 168 h. Blood samples were collected at ?240, 0, 6, 24, 72 and 168 h after challenge. Survival and serum cortisol, glucose, sodium and chloride levels were measured to determine stress response and osmoregulation condition. While TRP group showed no mortality until 168 h, cumulative mortality was near 100% at 72 h after challenge in control group. Feeding tryptophan-supplemented diet led to increase in prechallenge cortisol, but not glucose, sodium and chloride values at ?240 h that stayed elevated until 0 h after challenge. After challenge, cortisol and glucose values did not significantly affected by time of sampling but type of diet and diet × time interaction. Sodium values significantly affected by diet type and time of sampling but not their interaction. Chloride values significantly affected by time of sampling but not diet type and their interaction. Control group had higher cortisol, glucose and sodium than TRP at each time of sampling. Control and TRP group showed increasing and decreasing pattern in cortisol and glucose values when experiment progressed after osmotic challenge. Both group showed increasing pattern in sodium and chloride values when experiment progressed after osmotic challenge. Results indicated that tryptophan supplementation enhanced salt water tolerance of carp that is due to increase in basal cortisol and anti-stress effect of tryptophan and possibly increase in serotonergic activity.     

Potential growth and yield of one- and two-year-old carp, Cyprinus carpio L., in climatic conditions of la Dombes (France)

The potential growth and yield of 1- and 2-year-old carp, Cyprinus carpio L., in climatic conditions similar to those of la Dombes were determined by a stochastic-deterministic model, derived from data on growth of Polish carp cultured under intensive methods. The model's forcing functions are the water temperature, effective for carp body mass growth, recorded in ponds of la Dombes, the final fish density, the protein content in feeds and the initial body mass (for 2-year-old fish). It was assumed that the pond ecosystem does not limit fish growth and that the pond trophic chain works correctly. Quantification of relations between basic elements of the carp culture techniques enables prediction of the required final output from ponds, permitting the most efficient culture methods to be chosen.     

Pharmacokinetics of chloramphenicol in carp (Cyprinus carpio L.) after drug administration

Chloramphenicol (CAP) is a banned substance in fish farming; yet, residues are sometimes detected in farmed fish products. Therefore, it is important that tissue distribution and elimination rates of CAP are measured to allow monitoring of fish farms. The tissue distribution and residue of CAP in carp (Cyprinus carpio L.) after muscle injection was investigated. Chloramphenicol concentrations were determined using high‐performance liquid chromatography. Pharmacokinetics were used for the studies of CAP residue and the results showed that the CAP was easily assimilated in the liver, serum and gill, with the absorption rates of 6383, 3.02 and 1.39 h^?1, respectively, following a single‐dose injection of 80 mg kg bw^?1. The elimination half‐lives (t_1/2) were 22.28, 15.47, 14.87, 9.28 and 5.32 h for the liver, serum, gill, muscle and kidney respectively. The t_1/2 after 5 days of multi‐doses of repeated CAP injection with 40 mg kg bw^?1 was 1.09, 0.887, 0.872, 0.476 and 0.617 days for the five tissues respectively. The results validated that CAP in the liver, serum and gill could be markers for CAP residue analysis.     

Isometric twitch tension of lateral muscle in carp, Cyprinus carpio L., with sekoke disease

Abstract. Changes in blood properties and the chemical components, histology and isometric twitch tension of lateral muscle were studied in carp, Cyprinus carpio L., showing clinical signs of sekoke disease induced by a diet containing oxidized oil. When compared to normal fish, sekoke fish were found to have significantly lower mean blood pH, haematocrit, haemoglobin concentration and muscle water content. However, plasma lactate, lipoperoxide and total lipid concentrations were significantly higher in sekoke fish. It was found that in sekoke fish the maximum tension and the number of isometric twitches leading to complete fatigue of lateral muscle were greatly reduced. Histological studies confirmed that these reductions were related to the degree of structural damage within this tissue.     

Increased stocking density influences the acute physiological stress response of common carp Cyprinus carpio (L.)

The physiological response of common carp, Cyprinus carpio (L.) to increased stocking density and an additional acute net confinement stressor was investigated. Stocking densities were increased from 28.4 to 56.8 or 113.6 kg m^?3 by the use of crowding screens and fish were sampled from the crowded groups after 15, 39 and 87 hours of crowding (hc). A transient elevation of plasma cortisol was found in the higher density group after 15 hc before values returned to control levels. Increased stocking density also increased plasma levels of glucose, free fatty acids (FFA) and lactate during the experimental period. No effect was found on oxygen radical production in the blood, haemoglobin or haematocrit levels, but leucocrit values were lower after 39 hc in both groups. Net confinement resulted in a significant increase in plasma cortisol levels in all groups. However, after 15 hc, cortisol and FFA levels in both crowded plus confinement groups were higher than in the control and confined groups. Confinement resulted in increased oxygen radical production in the crowded plus confined groups at all times. Results indicate that although carp responded with a mild stress response to increased stocking density and adaptation occurred by 87 hc, the crowded fish were more sensitive to an additional acute stressor.