Structure of supporting elements in the dorsal fin of percid fishes

The dorsal fin is one of the most varied swimming structures in Acanthomorpha, the spiny‐finned fishes. This fin can be present as a single contiguous structure supported by bony spines and soft lepidotrichia, or it may be divided into an anterior, spiny dorsal fin and a posterior, soft dorsal fin. The freshwater fish family Percidae exhibits especially great variation in dorsal fin spacing, including fishes with separated fins of varying gap length and fishes with contiguous fins. We hypothesized that fishes with separated dorsal fins, especially those with large gaps between fins, would have stiffened fin elements at the leading edge of the soft dorsal fin to resist hydrodynamic loading during locomotion. For 10 percid species, we measured the spacing between dorsal fins and calculated the second moment of area of selected spines and lepidotrichia from museum specimens. There was no significant relationship between the spacing between dorsal fins and the second moment of area of the leading edge of the soft dorsal fin.     

Global patterns and clines in the growth of common carp Cyprinus carpio

This review provides a meta‐analytical assessment of the global patterns and clines in the growth of Cyprinus carpio as measured by length‐at‐age (L_t) or von Bertalanffy growth function (VBGF) parameters, mass–length relationship (W–L_t) and condition factor, based on literature data. In total, 284 studies were retrieved spanning 91 years of research and carried out on 381 waterbodies–locations in 50 countries in all five continents. Although native C. carpio achieved larger (asymptotic) size relative to its non‐native counterpart, the latter grew faster during the first 7 years of life. Lentic populations (especially in natural lakes) also achieved larger sizes relative to lotic ones and the same was true for populations in cold and temperate v. arid climates. Unlike previous studies (on much more restricted datasets), only weak latitudinal clines in instantaneous growth rate, L_t at age 3 and mortality were observed globally and this was probably due to the presence of counter‐gradient growth variation at all representative age classes (i.e. 1–10 years). Slightly negative allometry was revealed by the W–L_t and the related form factor tended to distinguish the more elongated and torpedo‐shaped body typical of the wild form from the deeper body of feral‐domesticated C. carpio. Existing population dynamics models for C. carpio will benefit from the comprehensive range of waterbody type × climate class‐specific VBGF parameters provided in the present study; whereas, more studies are needed on the species' growth in tropical regions and to unravel the possibility of confounding effects on age estimation due to both historical and methodological reasons.     

Social facilitation of learning in mixed-species schools of common carp Cyprinus carpio L. and Nile tilapia Oreochromis niloticus (L.)

The process of learning to associate a visual cue with food was studied in groups of common carp Cyprinus carpio and Nile tilapia Oreochromis niloticus by means of a classical conditioning paradigm. In the first phase of the study, fishes were conditioned in either single-species or mixed-species groups to associate a blinking blue light with food. In the second phase, group composition was altered so that only single species were reconditioned, composed of individuals previously paired with the same or the other species. In the first phase, in the single-species groups, Nile tilapia rapidly formed an association between the visual cue and food, whereas common carp failed to do so. In mixed-species groups, both Nile tilapia and common carp associated a visual cue with food. In the second phase of the study, Nile tilapia retained that ability irrespective of whether they had previously been trained in single-species or mixed-species groups, common carp previously trained with Nile tilapia, were not repelled by the blinking blue light and gradually approached it from a distance, whereas common carp previously trained in homogenous groups continued to be repelled by the blinking light. Fish arrivals and departures from the feeding zones as well as fish position in the testing apparatus were analysed and contrasted in single-species and mixed-species groups outside the training sessions, revealing mutual impacts of one species on the other in mixed-species groups. The findings of this study demonstrated interspecific social facilitation of learning to associate a visual cue with food.     

Characterization of a novel cell line from the caudal fin of koi carp Cyprinus carpio

A continuous cell line (KF‐101) derived from the caudal fin of the koi carp Cyprinus carpio was established and characterized. The KF‐101 cell line multiplied abundantly in Leibovitz's L‐15 medium containing 10% foetal bovine serum at 25° C, and was subcultured for >90 passages over a period of 3 years. Immunocytochemistry revealed that the KF‐101 cells contain keratin, junction proteins connexin‐43 and occludin, and ectodermal stem‐cell marker Pax‐6, but not vimentin. Furthermore, the KF‐101 cells reacted with anti‐human DARPP‐32 and anti‐human GATA‐4 antibodies, and the labelling was regulated according to the cell cycle. The labels of the DARPP‐32 and GATA‐4 antibodies in the KF‐101 cells were the suggested phosphatase‐1 inhibitor‐1 and GATA‐3, respectively. In addition, the KF‐101 cells were susceptible to koi herpesvirus but were resistant to eel herpesvirus, iridovirus, grouper nodavirus and chum salmon (Oncorhynchus keta) virus. The results indicate that the KF‐101 cells are suitable materials for investigating biological and virological development.     

Wing design and morphology of the harbor porpoise dorsal fin

The correlation between skin structure and hydrodynamic design of the dorsal fin of the harbor porpoise (Phocoena phocoena) was examined. For the study of fin morphology and geometry, a scheme of sampling representing a two-parameter mesh on the fin surface was used. At each data point the thickness of the epidermis, papillary and subpapillary layers of the dermis, the ligamentous layer of the fin, as well as the angle formed by the direction of dermal ridges and the fin root chord were measured. On the basis of fin cross-sections the three-dimensional surface models of the fin in a 1 : 1 scale were created with a CAD program. The shape of the model was evaluated by the wing and hydrofoil parameters (angle of leading edge sweep, leading edge radius, maximum thickness of the fin cross-section, and position of maximum thickness from the leading edge). Hydrodynamic performance of the fin cross-sections was studied with a CFD program. Regional variability of the parameters of morphology was compared with spanwise variability of the parameters of cross-sectional geometry. It was found that skin structure parameters correlate with the hydrodynamically relevant parameters of the fin and fin cross-sections. Regularities of skin structure of the harbor porpoise dorsal fin are considered indirect evidence of the adaptation of porpoise skin to the fin flow.     

Periodicity of reproductive behaviour by the blue tilapia,Oreochromis aureus

Synopsis Oreochromis aureus exhibits a diel periodicity of spawning when maintained on a controlled 14:10 light:dark photoperiod, with a peak in spawning activity during the 11th hour of light. That this periodicity of spawning is a response to light is supported by phase-shifting the light cycle by seven hours. This results in a corresponding shift in the times of spawning.     

Age and growth of the common carp, Cyprinus carpio, in the River Murray, Australia: validation, consistency of age interpretation, and growth models

The present study validates age estimates from a suite of calcified structures (scales, opercular bones and otoliths), assesses the consistency of age interpretations and evaluates growth models in common carp from the lower Murray River, Australia. Marginal increment analysis was used to validate annulus counts, with attention to the 'edge interpretation problem'. The formation of annuli occurred annually after pooling annulus groups, and in carp 4 and 5 years old. The regular alternation of opaque and translucent zones in opercular bones and whole otoliths of younger and older carp was also suggestive of annual periodicity. From systematic comparisons, the use of both opercular bones and whole otoliths in routine age determinations is recommended. Six growth models, including the von Bertalanffy growth function (VBGF) and five polynomial curves were tested to describe growth in length. A log-log quadratic function, by virtue of its precision, and the VBGF, with wider applicability and more biological realism, were chosen.     

Structure,organization and expression of common carp (Cyprinus carpio L.) NKEF-B gene

Natural killer (NK) cell enhancing factor (NKEF) belongs to the newly defined peroxiredoxin (Prx) family. Its functions are to enhance NK cell cytotoxicity and to protect DNA and proteins from oxidative damage. In this study, a partial cDNA sequence of carp NKEF-B was isolated from thymus cDNA library. Subsequently, the full-length cDNA of carp NKEF-B was obtained by means of 3′ and 5′ RACE, respectively. The full-length cDNA of carp NKEF-B was 1022 bp, consisting of a 73 bp 5′-terminal untranslated region (UTR), a 355 bp 3′-terminal UTR, and a 594 bp open reading frame coding for a protein of 197 amino acids. Carp NKEF-B contained two consensus Val-Cys-Pro (VCP) motifs and three consensus cysteine (Cys-51, Cys-70 and Cys-172) residues. Sequence comparison showed that the deduced amino acid sequence of carp NKEF-B had an overall similarity of 74–96% to that of other species homologues. Phylogenetic analysis revealed that carp NKEF-B forms a cluster with other known teleost NKEF-Bs. Then, by PCR we obtained a 5.1-k long genomic DNA of carp NKEF-B containing six exons and five introns. Real-time RT-PCR results showed that carp NKEF-B gene was predominantly detected in kidney and head kidney under un-infected conditions. Whereas under SVCV-infection condition, the expression of NKEF-B gene was significantly increased in blood cells, gill, intestine and spleen, but maintained in liver, and decreased significantly in kidney and head kidney. Finally, the rNKEF-B was constructed and expressed in Escherichia coli. By using an antibody against carp rNKEF-B, immunohistochemical study further indicated that NKEF-B positive cells are mainly some RBCs and a few epithelial cells in gill and intestine, and that under SVCV-infection condition, these positive cells or positive products in their cytoplasm were mainly increased in gill and spleen sections of carp. The results obtained in the present study will help to understand the function of NKEF-B in teleost innate immunity.     

Structure, organization and expression of common carp (Cyprinus carpio L.) SLP-76 gene

SLP-76 is an important member of the SLP-76 family of adapters, and it plays a key role in TCR signaling and T cell function. Partial cDNA sequence of SLP-76 of common carp (Cyprinus carpio L.) was isolated from thymus cDNA library by the method of suppression subtractive hybridization (SSH). Subsequently, the full length cDNA of carp SLP-76 was obtained by means of 3' RACE and 5' RACE, respectively. The full length cDNA of carp SLP-76 was 2007 bp, consisting of a 5'-terminal untranslated region (UTR) of 285 bp, a 3'-terminal UTR of 240 bp, and an open reading frame of 1482 bp. Sequence comparison showed that the deduced amino acid sequence of carp SLP-76 had an overall similarity of 34-73% to that of other species homologues, and it was composed of an NH2-terminal domain, a central proline-rich domain, and a C-terminal SH2 domain. Amino acid sequence analysis indicated the existence of a Gads binding site R-X-X-K, a 10-aa-long sequence which binds to the SH3 domain of LCK in vitro, and three conserved tyrosine-containing sequence in the NH2-terminal domain. Then we used PCR to obtain a genomic DNA which covers the entire coding region of carp SLP-76. In the 9.2k-long genomic sequence, twenty one exons and twenty introns were identified. RT-PCR results showed that carp SLP-76 was expressed predominantly in hematopoietic tissues, and was upregulated in thymus tissue of four-month carp compared to one-year old carp. RT-PCR and virtual northern hybridization results showed that carp SLP-76 was also upregulated in thymus tissue of GH transgenic carp at the age of four-months. These results suggest that the expression level of SLP-76 gene may be related to thymocyte development in teleosts.     

Effect of a non-hormonal feed additive,Cholymbi on growth,body composition and digestive enzyme activity of common carp,Cyprinus carpio

Supplementation of pelleted feeds (30% crude protein) consisting of practical ingredients with 250, 375 and 500 mg Cholymbi/kg diet resulted significantly improved the growth of common carp, Cyprinus carpio. Highest final average weight was recorded with diet containing 500 mg Cholymbi/kg. Feeding Cholymbi to fish showed increased carcass protein and fat. Gut protease and hepatopancreas amylase activity were the highest with 500 mg Cholymbi/kg incorporated diet (T3). The results of the present study suggest that Cholymbi, a non-hormonal growth promoter could be effectively used in the diet of common carp. Further investigations are required to work out the optimal dosage required in the diet of common carp.     

Morphological and phagocytic characteristics of peritoneal exudate cells in tilapia, Oreochromis niloticus (Trewavas), and carp, Cyprinus carpio L.

The morphology and phagocytic activity of peritoneal exudate cells (PEC) obtained by an intraperitoneal injection of liquid paraffin into tilapia, Oreochromis niloticus , and carp, Cyprinus carpio , were studied with light and electron microscopy. PEC consisted of monocyte-macrophage series cells (M-Mø), neutrophils, eosinophils (granular cells) and others. Cells exhibiting the same morphology as mammalian macrophages but different from monocytes of the same species were identified with light and electron microscopy and designated as peritoneal macrophages. Light and electron microscopy revealed that M-Mø, neutrophils and eosinophils (granular cells) phagocytozed foreign materials added in vivo and in vitro. Eosinophils appeared later in the peritoneal exudate and less actively phagocytic as compared with M-Mø and neutrophils. Small and large phagosomes were formed in M-Mø, neutrophils and eosinophils (granular cells). Large phagosomes were common in neutrophils. Fusion of cytoplasmic granules with the phagosome membrane was observed. The in vitro experiment on phagocytosis revealed that the phagocytic rates in M-Mø and neutrophils were positively correlated with the doses of foreign materials. The results indicated that these two cell types have the highest capacity of phagocytosis.     

A histophysiological study of muscle differentiation and growth in the common carp, Cyprinus carpio Var. communis

From an histochemical and biochemical study on the fibre differentiation and muscle growth in common carp, Cyprinus carpio Var. communis , growth and development processes have been characterized on the basis of differences in fibre size, fibre number, lipid content, succinic dehydrogenase (SDH) and myofibrillar adenosine triphosphatase (m-ATPase). A very early differentiation and zonal segregation of principal fibre types (red and white) and subsequent increase in muscle by their hypertrophy and hyperplasia was observed. These changes become pronounced after yolk sac absorption. The special character of the red muscle, as it develops from a superficial monolayered lateral sheet to a compact multicellular cone, was also investigated.     

The morphology of the club glands on the dorsal fin of mature male shannies, Lipophvys pholis (L.) (Blenniidae: Teleostei)

The pelvic, pectoral, anal and dorsal fins of mature male, female and immature male Lipophrys pholis (L.) were examined by light microscopy for the presence of club glands. All fins except the dorsal showed a highly stratified epidermis and a thick cuticle. Club glands were present on the dorsal fin of mature male fisH but only during the breeding season. The development and decline of the club glands corresponds to the period of gonadal build-up and spawnout. Each club gland comprises several thousand bundles ofcolumnar cells. The columnar cells surround acentral pore which opens to the outside through a layer of Malpighian cells. The substance produced by the gland includes mucopolysacchdride. The function of the secretion is unknown and is discussed in relation to studies on similar glands in several Mediterranean blenniids.     

Effect of methamidophos on the growth rate and esterase activity of the common carp Cyprinus carpio L.

The acute toxicity of methamidophos and three other compounds to fingerlings of the common carp Cyprinus carpio L. was determined. The 96-h LC₅₀ values were 68 mg/litre for methamidophos, 1.7 mg/litre for carbaryl, 0.21 mg/litre for lindane and 50 mg/litre for diquat.The acetylcholinesterase (AChE) and carboxylesterase (CarE) activities of the brain and liver were monitored over six weeks in fish poisoned with sublethal doses of methamidophos. Brain CarE was more sensitive than AChE but for the liver the reverse was true. In either case the degree of enzyme inhibition increased with increasing insecticide concentrations in the water.After exposure to methamidophos at 20 mg/litre for 48h liver AChE and CarE recovered faster than those of the brain. For both organs CarE recovered faster than AChE.At sublethal doses methamidophos affected the growth rate of the fish but no direct relationship between growth and insecticide concentrations could be established.     

Involvement of fibronectin during epiboly and gastrulation in embryos of the common carp,Cyprinus carpio

Summary The present report firstly describes a pilot study in which, during early development of embryos of the common carp, Cyprinus carpio, the cellular adhesion to fibronectin (FN) was blocked by administration of GRGDS peptide (which binds to the FN-receptor). As this treatment resulted in developmental aberrations, suggesting a functional role for FN, the major part of the work was focussed on the distribution of reactivity of anti-FN antibodies during epiboly and gastrulation. GRGDS treatment had a concentration dependent effect on development. Incubation of embryos in 1.5 mg/ml from the 32-cell stage onwards caused a retardation of epiboly, which did not proceed beyond 60%. The embryos did not show involution, as was confirmed by histological study. These preliminary results suggest that FN is involved in both epiboly and gastrulation of carp embryos. During cleavage, no specific extracellular binding of anti-FN antiserum could be observed. However, binding to a number of cell membranes took place from early epiboly onwards. After the onset of gastrulation, we observed a gradually increasing number of the deepest epiblast cells, showing immunostaining on part of their surface, facing the yolk syncytial layer (YSL) or the involuted cells. During early epiboly, anti-FN binding was restricted to areas in front of the migratory hypoblast cells. Later on, binding was found at the border of hypoblast and epiblast cells. At 100% epiboly, some contact areas of epiblast and hypoblast showed a discontinuous lining of reactivity, whilst other areas appeared devoid of anti-FN binding sites. The results indicate that FN is involved in the migration and guidance of hypoblast cells during gastrulation in carp. Correspondence to: P. Gevers     

Validating and corroborating the deposition of two annual growth zones in asteriscus otoliths of common carp Cyprinus carpio from South Africa's largest impoundment

A total of 816 common carp Cyprinus carpio asteriscus otolith pairs were collected from Lake Gariep, South Africa. Otoliths were interpreted whole, submerged in methyl salicylate and viewed under transmitted light. The precision of growth zone counts of the primary reader was estimated at 5·54 and 7·03% using the average per cent error method and the coefficient of variation, respectively. Age-bias plots indicated no systematic bias between the primary reader and the three secondary readers for up to nine growth zones (95% of the sample). Growth zone deposition rate was validated using a mark-recapture experiment of chemically tagged C. carpio (n = 21) conducted in a large earthen pond under ambient conditions in the vicinity of Lake Gariep. The validation results were corroborated for the wild population by edge analysis and a length-based age-structured model. All three methods suggest that growth zone formation occurred biannually, exemplifying the importance of age validation as a prerequisite for understanding the life history of C. carpio.