Effects of P-supply on growth and mineralization in mirror carp (Cyprinus carpio L.)

The effects of increasing levels of monocalciumphosphate-supply to a soybean meal based diet on growth and mineralization were investigated in common carp ( Cyprinus carpio L. ). To monitor the P-status, phosphorus-content of whole body and of dorsal scales, backbone and opercula were sampled. The results showed that 0.7% P kg⁻¹ DM from the native foodstuffs was insufficient for adequate performance. Adding inorganic phosphorus, growth and mineralization were enhanced and P-content of dorsal scales and whole body corresponded with the different amount of phosphorus in the diets.     

Ichthyophthirius multifiliis (Fouquet) in the mirror carp, Cyprinus carpio L.

Mirror carp were infected with Ichthyophthirius multifiliis (Fouquet) under standardized conditions. The size and number of parasites at selected sites on the body were recorded during the course of the infection. Initial exposure to 40 mature parasites resulted in a mild infection with 100% recovery after 18 days. Recovered fish did not appear to be carriers of the parasite. Exposure to 400 parasites resulted in 100% mortality between 22–25 days. The growth rate of the parasite was linear. Parasites were more numerous in the dorsal surface of the fish than in the lateral or ventral surface. The increase in parasite numbers during the disease was greater in the gills than in the skin.     

Ichthyophthiriasis in the mirror carp Cyprinus carpio (L.) III. Pathology

The microscopical pathology of Ichthyophthiriasis was studied in a group of mirror carp infected with measured numbers of parasites under standardized conditions. Primary pathology consisted of inflammatory, proliferative, and degenerative changes in the epidermis and hyperaemia and oedema of the spongiose dermis. This was accompanied by changes in the amount and distribution of pigment in the spongiose dermis. Proliferation of interlamellar epithelial tissue of the gills in response to the parasite resulted in partial or complete filling of the interlamellar spaces. Secondary changes noted in the disease were devacuolization of hepatocytes, leukocytic depletion of the mesonephric kidneys, and leukocytic metaplasia or hyperplasia in the spleen.     

Soybean meal induces intestinal inflammation in common carp (Cyprinus carpio L.)

The development of soybean meal (SBM) induced enteritis in the hindgut of the omnivorous common carp (Cyprinus carpio L.). The developed condition was assessed when carp, continuously fed on animal protein, were transferred to a diet in which 20% of the protein was replaced by SBM. After week 1, most of the inflammation parameters were already present, but at week 3, a strong aggravation of the condition was observed which included a shortening of the mucosal folds, the disappearance of the supranuclear vacuoles, an increased number of goblet cells, a thickened lamina propria and sub-epithelial mucosa with increased numbers of basophilic granulocytes as well as a decreased uptake capacity of enterocytes (impaired endocytosis and microvilli). Contrary to previous observations made with respect to Atlantic salmon, common carp start to recover from the fourth to the fifth week after switching to SBM feeding. At this stage, the supranuclear vacuoles refill and most of the parameters revert to basal levels. During the enteritis process, a real-time quantitative PCR analysis was conducted to measure the expression of inflammatory and anti-inflammatory cytokine genes in the isolated intraepithelial lymphocytes (IEL). The pro-inflammatory interleukin 1 beta (IL-1 beta) and tumour necrosis factor alpha1 (TNF-alpha1) genes were up-regulated during the inflammation process while the anti-inflammatory interleukin 10 (IL-10) was down-regulated after an initial up-regulation at week 1. Transforming growth factor beta (TGF-beta) expression showed an up-regulation from week 3 onwards despite the high Ct value and the low primer efficiency shown. This study confirms the contribution of IEL (mainly T-like cells) and basophils in the enteritis process. In addition, the results show a clear involvement of up- and down-regulated cytokine genes in both the onset and recovery of the SBM-induced enteritis in the hindgut of carp.     

Developmental response of carp,Cyprinus carpio,larvae fed different foods or starved

Synopsis The developmental interval, body length, dry and wet weight were determined in carp larvae during the first 2 weeks of exogenous feeding. Six feeding groups were reared at 26°C; four groups received different artificial diets, whereas zooplankton-fed larvae and unfed larvae served as controls. It was found that larval developmental rate can be modified by the type of food. The diet affects the relationship between developmental step and weight. The effect of diet on the relationship between development and length becomes manifest at older steps (after longer feeding the same diet). A threshold point, after which satisfactory results of feeding artificial diets to carp larvae can be expected, depends not only on body size but also on the degree of development.     

Effects of light on trace elments and triiodothyronine levels in plasma of mirror carp (Cyprinus carpio)

The changes of copper, zinc, iron, magnesium, manganese, and triiodothyronine as a result of short- and long-term isothermal exposure to light were determined in the plasma of mirror carp (Cyprinus carpio). Two groups of fish were subject to a 3-mo treatment that consisted of (1) 8h of light followed by 16 h of darkness and (2) 16 h of light followed by 8h of darkness at 25°C. No significant changes were recorded between the two groups at the beginning of the study. After 3 mo, the triiodothyronine and elements levels as well as the growth rates of fish in the long-time exposure period were significantly higher than those in the short-time exposure (p<0.05).     

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.     

Ichthyophthiriasis in the mirror carp Cyprinus carpio (L.) V. Acquired immunity*

Mirror carp (Cyprinus carpio L.) infected with sublethal doses of Ichthyophthirius multifiliis, were free of parasites 21 days after infection. Fish remained free of parasites for at least 8 months when maintained in an infective environment. Such fish were refractory to reinfection with numbers of parasites that killed all normal, previously unexposed fish. Serum from fish recovered from previous infections with sublethal doses of parasites, immobilized free-swimming stages of I. multifiliis to a dilution of up to 1: 1024. The rise in serum-immobilization titre occurred between the 10th and 22nd days of infection, the period during which parasites disappeared from the body surface of the fish. Infective stages of the parasite were unable to penetrate the mucus body covering of resistant fish.     

Ichthyophthiriasis in the mirror carp Cyprinus carpio (L.) IV. Physiological dysfunction*

Changes in blood ion concentration, oxygen absorption, blood haemoglobin concentration and blood urea-ammonia nitrogen level were measured in a group of mirror carp, Cyprinus carpio (L.) infected with measured numbers of Ichthyophthirius multifiliis under standardized conditions. The disease was characterized by a drop in serum sodium and magnesium and increase in serum potassium. The ability of infected fish to absorb oxygen was reduced as was their ability to tolerate dissolved oxygen concentrations under 5 ppm. Blood ureaammonia level was elevated during the disease but blood haemoglobin level remained unchanged.     

微卫星DNA标记分析德国镜鲤的遗传潜力

结合体重、体长、体高等数量性状, 用30个微卫星分子标记, 评估了3个德国镜鲤群体的遗传潜力, 共检测到287个等位基因, 559种基因型, 片段长度109~400 bp, 有效等位基因数1.1014~6.4665, 观察杂合度0.0968~0.9892, 期望杂合度0.0926~0.8554, 位点多态信息含量0.08787~0.8559, 其中中度多态(0.25≤PIC≤0.5)13个, 高度多态(PIC≥0.5)13个。统计结果显示: 3个群体的遗传潜力处于中度水平, 双来养殖群体的遗传潜力比换新和松浦繁殖群体低。同时, 用30个基因座的不同等位基因和基因型与双来群体的体重、体长、体高进行了连锁分析, 得到2个与镜鲤体长相关的微卫星分子标记(HLJ319, HLJ693)和1个与体高相关的位点(HLJ677), 与体长相关的1个位点(HLJ693)还与体重连锁。将此遗传标记在鲤鱼重组自交系中验证, 结果显示: 主要经济性状相连锁的3个遗传标记中HLJ319与鲤鱼体长性状的QTL定位结果基本一致。