• Journal of fish pathology
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• v.13 no.2
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• pp.147-151
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• 2000

Deformed vertebrae by cold shock in Rhynchocypris oxycephalus were discovered. Deformity was externally noticed in the caudal penducle region of R. oxycephalus. Radiographic and histologic investigation confirmed the deformity. Especially, histological investigations provided the fact that extensive fusion between neighbouring vertebrae is caused by removal of endogeneous mineralized tissue. Deformed vertebrae appeared suggesting the direct evidence of vertebral fusion had arisen internally by cold shock in this species.

• Korean Journal of Ichthyology
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• v.11 no.1
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• pp.33-41
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• 1999

The influence of nutritional conditions on the histological changes of hepatocyte and intestinal epithelium as well as hepatosmatic index (HSI), protein, RNA and DNA concentrations of liver of Rhynchocypris oxycephalus was tested. Although, the starved group showed higher concentrations of protein, DNA and RNA than the fed group, food deprivation resulted in a decrease in the HSI, hepatocyte nucleus size and nuclear height of the intestinal epithelium. The RNA-DNA ratio appears to be a useful index of nutritional status in R. oxycephalus and may be useful for determining if R. oxycephalus is in a period of rapid or slow growth at the time of sampling. Additionally, the data have been interpreted in detail and some biologically important relationships discussed.

• Development and Reproduction
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• v.2 no.1
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• pp.69-74
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• 1998

The early gonadal development and sexual differentiation of Rhynchocypris oxycephalus are described from the stage of hatching to 150 days after hatching. During this peroid, the average length of the body grew from 0.64 cm to 5.96 cm. the primordial germ cells (PGCs), which could be recognized at the time of hatching, began to protrude into peritoneal cavity at a standard total length of 1.91 cm. At a standard total length of 2.29cm, initial ovarian differentiation wasidentified by the transformation of PGCs to meiotic oocytes. Finally, at the standard total length of 5.96 cm, the female gonads gradually developed towards migratory nucleus oocytes, characterisiing the maturation. Oocytes proliferated rapidly after sex differentiation while the testis entered a period of quiescence, as they continued to multiply but did not undergo growth until the standard total length of 4.00 cm. At a standard total length of 4.00 cm, spermatocytes arrested in thephase of interkinesis, Sertoli-like cells and sperm duct formation, with signs of meiotic activity, were observed. Therefore it may be concluded that R. oxycephalus belongs to the differentiated type of gonochoristic teleosts.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 1998.06a
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• pp.323-324
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• 1998

• Journal of Aquaculture
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• v.13 no.3
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• pp.193-196
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• 2000

Rhynchocypris oxycephalus and R. steindachneri show very similar karyotypes: 2n=50(EN=90), consisting of 12 metacentics, 28 submetacentrics and 10 acrocentrics with a gradual decrease in chromosome size, but with significant differences in nuclear DNA content of 2.64 and 2.52 pg/nucleus, respectively (P<0.05). Although the erythrocyte measurement and parameters of two species were similar, R. oxycephalus erythrocyte number was lower than that of R. steindachneri. Mode in karyological evolution within the genus Rhychocypris shows an increase of nuclear DNA without apparent changes in karyotype and erhthrocyte size.

• Journal of Aquaculture
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• v.11 no.1
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• pp.59-66
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• 1998

The effectiveness of lidocaine HCI (lidocaine HCI/sodium bicarbonate mixture) was tested as an anaesthetic for Rhynchocypris oxycephalus and R. steindachneri at three different temperatures of $10^{\circ}C.$, $15^{\circ}C.$ and $20^{\circ}C.$. Based on the exposure and recovery time, effective doses of lidocaine HCI were proven to be 300ppm ($20^{\circ}C.$), 400ppm ($15^{\circ}C.$), and 600ppm($10^{\circ}C.$) for R. oxcephaus, and 400ppm ($20^{\circ}C.$), 500ppm ($15^{\circ}C.$), and 600ppm ($10^{\circ}C.$) for R. steindachneri respectively. Anaesthetic dose and temperature-dependent relationship in exposure and recovery time were obseved for these two Rhynchocypris spops. There were size-related increases of exposure time on R. steindachneri in each dose of lidocaine HCI. However, dost-dependent increase of recovery time wea found in only the large size group of Rhynchocypris spp.

• Korean Journal of Veterinary Research
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• v.46 no.1
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• pp.35-41
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• 2006

Vitellogenin (Vtg), a phospholipoglycoprotein precursor of egg yolk is synthesized and secreted from the liver in response to estrogens in female fish. Vtg is normally undetectable in the blood of male fish, but can be induced by exposure to chemicals possessing estrogenic activity. Thus, the presence of Vtg in blood of male fish can serve as a useful biomarker for assessing previous exposure to estrogenic compounds. In the present study, Vtg was abnormally expressed in Rhynchocypris oxycephalus using estradiol benzoate ($E_2$). As the result, it was found that the level of Vtg in blood from R. oxycephalus was increased by treated quantity of $E_2$ with dose-effect manner. Monoclonal antibodies were generated against Vtg of R. oxycephalus. The hybridoma were screened with an enzyme immunoassay for the production of specific anti-Vtg antibodies. Five positive cell lines with a high specificity were selected. Monoclonal antibodies against vtg of R. oxycephalus that was developed in this study, may be a useful bio-indicator for the detection of estrogenic contamination in the aquatic ecosystem.

• Korean Journal of Ichthyology
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• v.19 no.1
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• pp.16-23
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• 2007

Oocyte surface in two Korean minnows, Rhynchocypris oxycephalus and R. kumgangensis was examined by light and electron microscope. In two species, the development of the oocyte was similar, but the follicular layer surrounding full-grown oocyte showed an evident difference. In R. oxycephalus, the follicular layer at the yolk vesicle stage became bilaminar with the retention of its outer squamous cell layer and the acquisition of an inner cuboidal or round cell layer just over the zona radiata. As the oocyte grows, the cuboidal cells of the inner follicular layer began to be replaced by columnar cells. At the yolk granule stage, the columnar cells secreted mucin to their cytoplasm (adhesive materials) and then surround the entire oocyte, as bundles of fence-shaped structures. Whereas, although the follicular layer of R. kumgangensis had an outer squamous layer and an inner cuboidal or round cell layer at the yolk vesicles as in R. oxycephalus, no inner cells were more changed with the retention of its cuboidal or round cells. Finally, in R. kumgangensis, the adhesive materials did not occur. In Korean two minnows, the structural difference in the oocyte surface seems to be related to their habitats and spawning characteristics as well as taxonomic characters.

• Journal of Aquaculture
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• v.11 no.2
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• pp.167-172
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• 1998

Rhynchocypris oxycephalus was incised through the midlateral line between the dorsal and pectoral fins and the wounds were closed with absorbable synthetic suture, and here we describe histological details on the nature of second-intention wound healing, rate of healing, and the nature of granulation tissue contraction. Postoperative survivals were 95% and 99%, compared to 100% for counterpart control fish, among fish at just and 7 days after surgery, respectively. By 14~42 days after surgery, fish had no mortality. The granulation tissue was epithelialized from day 7 through day 22 postsurgery. By 28 days postsurgery, the granulation tissue had contracted the wound margins into apposition. By 35~42 days postsurgery, the granulatin tissue contained collagen fiber and the epidermis contained well-differentiated alarm substance cells ; thus, the epidermis over the wound site was histologically normal in most fish, showed that wound healing was essentially complete within 35 days of surgery.

• Korean Journal of Environmental Biology
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• v.22 no.3
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• pp.351-368
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• 2004

Following the previous experiments, a starvation experiment was conducted to determine the influence of feeding and starvation on the histological and biochemical changes, the morphormetric changes in the sectioned body and the morphometric changes in Rhynchocypris oxycephalus (Sauvage and Dabry). The influence of starvation on nutritional conditions of the histological changes of hepatocyte and intestinal epithelium as hepatosmatic index (HSI), protein, RNA and DNA concentrations of liver in R. oxycephalus was tested. Although the starved group showed higher concentrations of protein, DNA and RNA than the fed group, food deprivation resulted in a decrease in the HSI, hepatocyte nucleus size and nuclear height of the intestinal epithelium. The RNA - DNA ratio appears to be a useful index of nutritional status in R. oxycephalus and may be useful for determining if R. oxycephalus is in a period of rapid or slow growth at the time of sampling. Additionally, the data have been interpreted in detail and some biologically important relationships discussed. The effects of starvation on the morphometrical changes in sectioned body traits, condition factor, viscera index and dressing percentage were determined for evaluating nutritional conditions of R. oxycephalus. Starvation for nine weeks resulted in a decrease in most sectioned traits as well as in condition factor and viscera index (P<0.05). These findings suggest that nutritional parameters used in this study appear to be a useful index for nutritional status in this species. The data has been interpreted in detail and some important body sectioned values of interest to commercial growers discussed. A 75-day study was conducted to determine the effect of starvation on classical and truss parameters in R. oxycephalus. Truss dimensions of almost the entire head and trunk region as well as the abdomen were increased significantly through feeding or starvation (P<0.05). Truss dimensions of the caudal region generally decreased through feeding or starvation, particularly those dimensions at the hind part of the trunk. There were some significant decreases in classical dimensions of the head region during feeding, in relation to body depth characteristics in the trunk and caudal region during starvation, whereas there was only one decreasing classical dimension in the caudal region during feeding. The results of this study indicate that application of the truss network as a character set enforces classical coverage across the body form, discrimination among experimental groups thus being enhanced. Considering that the dimension of the lower part of the head and some truss and classical dimensions were least affected by feeding and starvation, these dimensions may then be useful as a taxonomical indicator to discriminate the species of Rhynchocypris sp. The value of trunk region dimensions with a large component of body depth in R. oxycephalus is most likely to be compromised by variability related to differences in feeding regimes of fish in different habitats.