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.     

Storage of common carp, Cyprinus carpio L., eggs for short durations

In this study, a short-term storage of pre-activated eggs of the Japanese ornamental (koi) carp, Cyprinus carpio L., at three different temperature regimes is reported. Koi eggs were stored at low temperatures (6-9^oC), at variable or high temperatures (12-31C) and at moderate-stable temperatures (20-24.5^oC). Survival of the developing embryos was examined at the first and the second day post-activation, and in hatch-out larvae. Survival was calculated for each treatment by linear regression Y = a-bX (P± 0.01), except for eggs incubated at temperature of about 20 C(P > 0.1).The specific mortality index (b/a 100), as a ratio between the mortality rate (b) and the fertilization rate (a), indicated that the highest mortality is associated with the high and unstable storage temperatures, while the lowest mortality is with the moderate and stable storage temperatures. Eggs can be stored at moderate and stable temperatures for a maximal duration of 6h, yielding survival of hatch-out larvae higher than 50%. In two trials, fertilization potency of sperm stored in a domestic refrigerator (5-9^oC) for 5h, was compared with freshly stripped sperm and no differences in fertilization rates were found between the two treatments.     

Upper lethal and rearing temperatures for juvenile common carp, Cyprinus carpio L., and silver carp, Hypophthalmichthys molitrix (Valenciennes)

Abstract. The ultimate upper lethal temperature (UULT) was 43.0 or 46.0°C for common carp and 43.5 or 46.5°C for silver carp, depending on the method of calculation. The influence of fish age on lethal temperature values was low. Using the relationship between the UULT and the optimum growth temperature the latter was calculated as being 38°C for common carp and 39°C for silver carp. No significant differences were found in survival of fish reared at lower and higher temperatures when proper food was used.     

Cryopreservation of sperm of common carp, Cyprinus carpio L.

Milt of common carp, Cyprinus carpio L. was cryopreserved in pellet form with the use of 12 extenders. Most efficient were: BE2 original extender (containing 85 mM NaCl, 50 mM KCl, 3 mm CaCl₂, 1 mm MgCl₂ with 10% dimethyl-acetamide (DMA) and 10% addition of hen's egg yolk) and Kurokura et al.'s extender with 15% DMA and 10% yolk (about 73% and 69% of eyed eggs, about 61% and 52% of swim-up larvae, respectively). Within the most effective treatments, survival from the eyed-egg stage to the swim-up stage was similar to that observed in the control group. Survival from the eyed-egg stage to the swim-up stage (percentage of eyed eggs was considered as 100%) was highly significantly and positively correlated with the actual rate of swim-up larvae.     

鲤胸腺素Tβ全长cDNA的克隆与序列分析

应用荧光DDRT-PCR从鲤外周血白细胞克隆了鲤胸腺素β(thymosinβ,Tβ)基因cDNA全序列。序列分析表明,TβcDNA全长528bp,其完整的读码框架位于40～178bp,编码46个氨基酸,5'非编码区长39bp,3'非编码区长为348bp,且具有Poly(A)加尾信号(AATAAA),将该基因序列递呈GenBank,注册序列号为AY457946。氨基酸序列同源性分析显示,鲤Tβ氨基酸序列与鲤Tβa、斑马鱼Tβa及斑马鱼Tβ-2同源性均为84%。在系统发生树上,鲤Tβ与鲤、斑马鱼、白斑狗鱼和鲑Tβa及斑马鱼Tβ2聚类。     

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。     

A calcified fibroma in the common carp, Cyprinus carpio L.

Abstract. A large tegumental tumour was observed in a common carp from the pool of the Jardin des Plantes, Montpellier. The tumour was a fibroma characterized by centripetal fibrogenesis and intense calcification of the central region.     

Genetic characterization of wild Dutch common carp (Cyprinus carpio L.)

Six male carp, caught in the water system surrounding the Anna Paulowna (AP) Polder in The Netherlands, were characterized using allozyme and microsatellite markers. At the sMDH‐A1,2* loci an allele was found, which has previously only been found in wild River Rhine and wild Vietnamese common carp. Microsatellite allele frequencies showed that these AP carp were significantly different from a group of carp originating from several different domesticated strains. Based on both allozyme and microsatellite data, the AP carp probably originated from a wild or feral self‐sustaining population.     

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.     

Immunomodulatory effect of cimetidine in common carp (Cyprinus carpio L.)

The main indication of cimetidine is being H₂-receptor antagonist, but studies suggest that cimetidine may also act as a non-specific stimulant of cell-mediated immunity and immunomodulator. In order to determine the immunomodulatory effect of dietary intake of cimetidine in the common carp (100 ± 10 g), subjects were fed diets containing 0 (control), 50, 100 and 200 mg cimetidine kg^?1 of dry diet for a period of 6 weeks. TLC and NBT assays were significantly (P < 0.05) stimulated in cimetidine-supplemented groups displaying the highest value in 200 mg kg^?1 group. A decrease (P < 0.05) in cortisol and ACH50 value was recorded in fish treated with cimetidine. Serum protein, albumin and serum globulin levels were not significantly changed. The findings of the present investigation suggest that the incorporation of cimetidine in the diet of common carp enhances the non-specific immunity.     

Changes in skin mucus of common carp,Cyprinus carpio L., after exposure to water with a high bacterial load

Water in aquaculture systems may contain a high load of microorganisms. Reduction in overall bacterial tank water load improves fish health and growth parameters. In this study, the effect of an increase of overall bacterial load in tank water on carp skin mucus was assessed. Intracellular and released high molecular weight glycoproteins (HMGs) of carp skin mucus were analysed for changes using histological, histochemical and biochemical techniques. Increase of bacterial load did not induce obvious clinical responses in carp, but the skin of exposed carp responded quickly. The amount of skin mucus HMGs isolated increased as well as their total glycosylation. An increased goblet cell number was observed for all carbohydrate stainings, but most clearly for acidic glycoconjugates. A change in the terminal presence of some sugars was also seen. After the initial response of carp, an adaptation to the higher bacterial load in the water appeared to occur as mucins had a higher glycosylation. The changes observed suggest that these skin mucus adaptations are part of a primary defence mechanism of mucosal epithelia, even at a low pathogenic pressure.     

Protective effect of sodium alginates against bacterial infection in common carp, Cyprinus carpio L.

Abstract. A hot-water extract of Undaria pinnatifida was found to contain polysaccharide(s) which showed immunostimulating activity in fish. In order to identify the effective component(s), the hot-water extract was fractionated and acid-soluble (Fraction I) and acid-insoluble (Fraction II) polysaccharides were evaluated for their potential to enhance protection against Edwardsiella tarda infection in common carp. Intraperitoneal injection of Fraction II in carp 6 and 3 days prior to challenge with E. tarda resulted in a significantly greater survival rate than that of control fish at doses of 10–30mgkg^-1. On the other hand, Fraction I was not effective at any dose. Chemical and physicochemical analyses revealed that Fraction II was sodium alginate with a high degree of purity, with a molecular weight of 45000 and an M/G ratio of 0.8. Some commercial alginates were similarly evaluated for their efficacy. Alginates from Macrocystis pyrifera (MW, 146000-264000; M/G ratio, 0.9–1.0) significantly increased survival rate, but alginates from Lessonia nigrescens (MW, 177000–290000; M/G ratio, 1.3) had little effect. There are indications that the efficacy (protective effect) of alginates has some relationship to their M/G ratios.     

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.     

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.     

Effect of buffers on the gill structure of common carp, Cyprinus carpio L., and rainbow trout, Oncorhynchus mykiss (Walbaum)

Abstract. The effects of phosphate and tris buffers on the gill structure of common carp, Cyprinus carpio L, and rainbow trout, Oncorhynchus mykiss (Walbaum), were investigated. Common carp maintained in phosphate-buffered (a combination of sodium di-hydrogen phosphate and di-sodium hydrogen phosphate at a final concentration of 0.01 m ) standard dilution water for a period of 8 days developed severe pathological changes in the gill tissues, while carp maintained in tris-buffered (0.01 m ) dilution water and trout subjected to either of these buffers showed no such changes. Histological changes in the gills of carp exposed to phosphate buffered dilution water included an extensive mucous cell proliferation on the lamellar and filarnental epithelium, and an increased infiltration of eosinophilic granular cells into the gill tissues. A moderate epithelial hyperplasia and an increase in the chloride cell densities on the gill epithelia were also noted. The implications of these findings on the widely accepted practice of the use of phosphate salts and various other buffers in pH control of experimental water are highlighted.     

棉酚对鲤鱼急性中毒的研究

鲤鱼（体重约16克）腹腔注射乙酸棉酚0，7．3，54，100，200，400mg/kg体重，经四天（96小时）后，死亡率分别是0，0，20％，70％，90％，100％。96小时半数致死剂量是63．6mg/kg体重。注射剂量高于54mg/kg体重时，发生腹腔红肿、体壁溃烂，甚至死亡。实验结果说明虽然棉籽水平的棉酚不引起鲤鱼的任何可见的中毒症状，但是腹腔注射大剂量棉酚可引起与哺乳类相似的中毒症状。     

鲤硒缺乏的病理学

将健康幼鲤360尾设置3个相同平行处理,每个处理用鱼120尾,随机分为四组,分别投以0、0.15、0.30和0.45 mg/kg硒水平的饲料,各试验组的发病率和死亡率与日粮中硒含量高低呈负相关,其发病率分别为46.7%、33.3%、13.3%和0%,死亡率分别为26.7%、16.7%、6.7%和0%.病鱼出现特征性的瘦背症和脊柱弯曲等症状.组织学上最突出的变化表现为营养性肌病、营养性肝病、胰腺的变性、坏死等多器官组织的退行性变化.超微结构上,骨骼肌纤维、肝细胞和肾小管上皮细胞线粒体肿胀,嵴断裂,甚至发生溶解,整个线粒体呈囊泡状.硒缺乏幼鲤血液中谷草转氨酶(AST)、谷丙转氨酶(ALT)活性升高,谷胱甘肽过氧化物酶(GSH-Px)、过氧化物歧化酶(SOD)活性降低,丙二醛(MDA)含量升高.     

Enhancement of Hsp70 synthesis protects common carp, Cyprinus carpio L., against lethal ammonia toxicity

Exposure to TEX‐OE^®, a patented extract of the prickly pear cactus (Opuntia ficus indica) containing chaperone‐stimulating factor, was shown to protect common carp, Cyprinus carpio L., fingerlings against acute ammonia stress. Survival was enhanced twofold from 50% to 95% after exposure to 5.92 mg L^?1 NH₃, a level determined in the ammonia challenge bioassay as the 1‐h LD50 concentration for this species. Survival of TEX‐OE^®‐pre‐exposed fish was enhanced by 20% over non‐exposed controls during lethal ammonia challenge (14.21 mg L^?1 NH₃). Increase in the levels of gill and muscle Hsp70 was evident in TEX‐OE^®‐pre‐exposed fish but not in the unexposed controls, indicating that application of TEX‐OE^® accelerated carp endogenous Hsp70 synthesis during ammonia perturbation. Protection against ammonia was correlated with Hsp70 accretion.