Skin Of Common Carp Research Articles

Proteins of the Ciliated Protozoan Parasite Ichthyophthirius multifiliis Identified in Common Carp Skin Mucus.

The skin mucus is the fish primary defense barrier protecting from infections via the skin epidermis. In a previous study, we have investigated the proteome of common carp (Cyprinus carpio) skin mucus at two different time points (1 and 9 days) post-exposure to Ichthyophthirius multifiliis. Applying a nano-LC ESI MS/MS technique, we have earlier revealed that the abundance of 44 skin mucus proteins has been differentially regulated including proteins associated with host immune responses and wound healing. Herein, in skin mucus samples, we identified six proteins of I. multifiliis associated with the skin mucus in common carp. Alpha and beta tubulins were detected in addition to the elongation factor alpha, 26S proteasome regulatory subunit, 26S protease regulatory subunit 6B, and heat shock protein 90. The identified proteins are likely involved in motility, virulence, and general stress during parasite growth and development after parasite attachment and invasion. Two KEGG pathways, phagosome and proteasome, were identified among these parasite proteins, mirroring the proteolytic and phagocytic activities of this parasite during host invasion, growth, and development, which represent a plausible host invasion strategy of this parasite. The results obtained from this study can support revealing molecular aspects of the interplay between carp and I. multifiliis and may help us understand the I. multifiliis invasion strategy at the skin mucus barrier. The data may advance the development of novel drugs, vaccines, and diagnostics suitable for the management and prevention of ichthyophthiriosis in fish.

Enrichment of common carp (Cyprinus carpio) diet with Malic acid: Effects on skin mucosal immunity, antioxidant defecne and growth performance

Abstract The present study investigated possible effects of dietary malic acid on the expression of immunity, antioxidant and growth related genes expression as well as skin mucus immune parameters in common carp. Common carp (Cyprinus carpio) fingerlings were fed diets supplemented with different levels (0 [control], 0.5%, 1%, 2%) of malic acid (MA) for 60 days. The results revealed highest expression levels of immune-related genes (tnf-alpha, il1b, il8 and lyz) in skin of common carp fed 2% MA (P < 0.05). Regarding 1% MA treatment comparison with control group, significant difference was noticed just in case of lyz (P < 0.05). Evaluation of growth related genes expression revealed no significant difference between treatments (P > 0.05). The study of antioxidant related genes (gsta and gpx) in common carp skin fed with MA, showed significant difference between treated groups and control (P < 0.05). Carps fed with 2% MA had highest alkaline phosphatase activity in skin mucus compared other treated groups and control (P < 0.05). There were no significant difference between 0.5% and 1% and control (P > 0.05). The study of total protein and total immunoglobulin (Ig) in common carp skin musus revealed no alteration following MA treatment (P > 0.05). The present data demonstrated that feeding with MA altered immune and antioxidant genes expression in skin mucus of common carp.

Transcriptome sequencing and analysis for the pigmentation of scale and skin in common carp (Cyprinus carpio).

Teleost scale not only provides a protective layer resisting penetration and pathogens but also participate in coloration. It is interesting to study the mechanism of teleost scale formation. Furthermore, whether there existed consensus genes between scale coloration and skin coloration has not been examined yet. We analyzed the transcriptome profiles of red scale, white scale, red skin, and white skin of common carp (Cyprinus carpio). Pair-wise comparison identified 3391 differentially expressed genes (DEGs) between scale and skin, respectively. The 1765 up-regulated genes (UEGs) in scale, as the down-regulated genes in skin, preferred mineralization and other scale development-related processes. The 1626 skin UEGs were enriched in the morphogenesis of skin and appendages. We also identified 195 UEGs in white scale and 223 UEGs in red scale. The white scale UEGs primarily participated in regulation of growth and cell migration. The UEGs in red scale preferred pigment cell differentiation and retinoid metabolic process. A total of 22 DEGs had consensus expression patterns in skin and scale of the same coloration. The expression levels of these DEGs clearly grouped skin and scale of the same coloration together with principle component analysis and correlation analysis. Eleven consensus DEGs were homologous to the orthologs of Poropuntius huangchuchieni, 82% of which were under strong purifying selection. Eight processes including lipid storage and lipid catabolism were shared in both scale pigmentation and skin pigmentation. We identified consensus DEGs and biological processes in scale and skin pigmentation. Our transcriptome analysis will contribute to further elucidation of mechanisms of teleost scale formation and coloration.

Health Risks associated with residual pesticide levels in fish reared in purified wastewater from slaughterhouse

The main objective of the present research was to determine the concentrations of the selected pesticides in muscle, liver and skin of common carp. Fish were sampled in two different seasons from fish pond which received previously treated slaughterhouse wastewater. Pesticides including etridiazole, chloroneb, trifluralin, propachlor, chlorothalonil, hexa-chlorocyclopentadiene, atrazine, simazine, alachlor, metribuzin, metolachlor, DCPA, cyanazine, chlorobenzilate, endrin aldehyde, cis permethrin and trans permethrin were determined by using a GS-MS method. Many of pesticides were not determined or determined in low concentrations. Propachlor was found in muscle, skin and liver. The recommended acceptable daily intake was higher in comparison with the estimated daily intake for examined pesticides via fish reared in treated slaughterhouse wastewater. It is very important to maintain the safety of the fresh fish produced in wastewater in order to ensure food safety and avoid health problems in humans.

Occurrence and dietary exposure of organochlorine pesticides in common carp obtained from integrated production systems

ABSTRACTThe aim of this study was to determine the level of the organochlorine pesticides (OCPs) in meat, liver and skin of common carp. Fish were collected in spring and in autumn from fishpond that receives purified water from slaughterhouse. OCPs, including α-HCH, β-HCH, δ-HCH, lindane, heptachlor, aldrin, heptachlor epoxide, trans-chlordane, cis-chlordane, endosulfan I, DDE, dieldrin, endrin, DDD, endosulfan II, dichlorodiphenyltrichloroethane (DDT), endosulfan sulphate, methoxychlor, and endrin ketone, were determined by using a gas chromatography–mass spectrometry method. OCPs were present at low concentrations and only aldrin was detected in all examined tissues. The estimated daily intake for OCPs via common carp from integrated system of production was at the lower level compared with the acceptable daily intake recommended by different organisations, showing no significant risk on consumers.

Can dietary jujube (Ziziphus jujuba Mill.) fruit extract alter cutaneous mucosal immunity, immune related genes expression in skin and growth performance of common carp (Cyprinus carpio)?

The present study investigates the effect of dietary Ziziphus jujube fruit extract [ZJFE] on skin mucus non-specific immune parameters as well as mRNA levels of immune related gene in the skin of common carp fingerlings. An eight-week feeding trial was performed using different levels of dietary ZJFE (0, 0.25, 0.5 and 1%). At the end of the trial skin mucus immune parameters (total Ig, lysozyme and protease activity), cytokines genes (il1b, il8, il10 and tnf-alpha) expression in skin and growth performance were studied. The result showed highest and lowest skin mucus total Ig were observed in fish fed diet containing 0.5% ZJFE and control group, respectively (P < 0.05). There were no significant difference among treatments regarding skin mucus lysozyme activity (P >0.05). It should be noted that, feeding on 0.5 and 1% ZJFE significantly increased skin mucus protease activity (P <0.05). Likewise, gene expression studies in skin showed significant increase of il1b expression in fish fed 0.5% ZJFE compared other treatments (P <0.05). Also, il8 gene was noticeably up-regulated in 0.5 and 1% treatments compared to the control group (P <0.05). While there were no significant difference between 0.25% JFE treatment and control in case of relative il10 gene expression (P >0.05), feeding on diets containing 0.5% or 1% ZJFE significantly down-regulated il10 gene (P <0.05). Our study indicated that relative expression of tnf-alpha gene significantly increased in treated groups (P <0.05). Also, feeding on ZJFE supplemented diet improved growth performance parameters. Overall, this experiment demonstrated the potentially useful effects of ZJFE on skin mucosal immunity and performance of common carp fingerlings.

Quantitative proteomic profiling of immune responses to Ichthyophthirius multifiliis in common carp skin mucus

Ichthyophthirius multifiliis, a ciliated protozoan parasite, causes ichthyophthiriasis and leads to considerable economic losses to the aquaculture industry. Understanding the fish immune response and host-parasite interactions could support developing novel strategies for better disease management and control. Fish skin mucus is the first line of defence against infections through the epidermis. Yet, the common carp, Cyprinus carpio, protein-based defence strategies against infection with I. multifiliis at this barrier remain elusive. The skin mucus proteome of common carp was investigated at 1 day and 9 days post-exposure with I. multifiliis. Using nano-LC ESI MS/MS and statistical analysis, the abundance of 19 immune related and signal transduction proteins was found to be differentially regulated in skin mucus of common carp in response to I. multifiliis. The analysis revealed increased abundance values of epithelial chloride channel protein, galactose-specific lectin nattection, high choriolytic enzyme 1 (nephrosin), lysozyme C, granulin and protein-glutamine gamma-glutamyltransferase 2 in I. multifiliis-exposed carp skin mucus. Multiple lectins and a diverse array of distinct serpins with protease inhibitor activity were identified likely implicated in lectin pathway activation and regulation of proteolysis, indicating that these proteins contribute to the carp innate immune system and the protective properties of skin mucus. The results obtained from this proteomic analysis enables a better understanding of fish host response to parasitic infection and gives insights into the key role skin mucus plays in protecting fish against deleterious effects of I. multifiliis.

Quantitative shotgun proteomics distinguishes wound-healing biomarker signatures in common carp skin mucus in response to Ichthyophthirius multifiliis

Ichthyophthirius multifiliis is a ciliated protozoan parasite recognized as one of the most pathogenic diseases of wild and cultured freshwater fish. Fish skin mucus plays a significant role against invading pathogens. However, the protein-based modulation against infection with I. multifiliis, of host fish at this barrier is unknown. Thus, we investigated the skin mucus proteome of common carp using a shotgun proteomic approach at days 1 and 9 after I. multifiliis exposure. We identified 25 differentially expressed proteins in infected carp skin mucus. Upregulated proteins were mainly involved in metabolism, whereas downregulated proteins were mainly structural. This is the first proteomic analysis of infected common carp skin mucus, and it provides novel information about proteome alteration caused by I. multifiliis. Furthermore, we identified novel proteins with yet unknown function in common carp following penetrating injuries such as olfactomedin 4, lumican, dermatopontin, papilin and I cytoskeletal 18. This analysis, therefore, represents a key for the search for potential biomarkers, which can help in a better understanding and monitoring of interactions between carp and I. multifiliis. This proteomic study not only provides information on the protein-level pathways involved in fish-ciliate interactions but also could represent a complementary system for studying tissue repair.

Enrichment of common carp (Cyprinus carpio) diet with medlar (Mespilus germanica) leaf extract: Effects on skin mucosal immunity and growth performance

A feeding trial was performed to assess the effects of dietary Medlar (Mespilus germanica) leaf extract (MLE) on the growth performance, skin mucus non-specific immune parameters as well as mRNA levels of immune and antioxidant related genes in the skin of common carp (Cyprinus carpio) fingerlings. Fish were fed diets supplemented with graded levels (0, 0.25, 0.50, and 1.00%) of MLE for 49 days. The results revealed an improvement to the growth performance and feed conversion ratio in MLE fed carps (P < 0.05), regardless of the inclusion level. The immunoglobulin levels and interleukin 8 levels in the skin mucous and skin, respectively, revealed significant increment in fish fed 1% MLE (P < 0.05) in comparison with the other MLE treatments and control group. Also, feeding on 0.25% and 0.50% MLE remarkably increased skin mucus lysozyme activity (P < 0.05). However, there were no significant difference between MLE treated groups and control (P > 0.05) in case protease activity in the skin mucous or tumor necrosis factor alpha and interleukin 1 beta gene expression in the skin of carps (P > 0.05). The expression of genes encoding glutathione reductase and glutathione S-transferase alpha were remarkably increased in MLE fed carps compared to the control group (P < 0.05) while carp fed 0.50% or 1.00% MLE had significantly increased glutathione peroxidase expression in their skin (P < 0.05). The present results revealed the potentially beneficial effects of MLE on the mucosal immune system and growth performance in common carp fingerlings.

New type of pathogenicity of Thelohanellus kitauei Egusa & Nakajima, 1981 infecting the skin of common carp Cyprinus carpio L.

Thelohanellus kitauei Egusa & Nakajima, 1981 is a common parasite infecting the intestine of common carp Cyprinus carpio L., resulting in mass mortality or loss of economic value of cultured carp. In the present study, T. kitauei infecting host skin was detected. The morphological, molecular and histological data of this parasite in the new organ record are presented. Morphological analysis showed the current specimen morphologically similar to T. kitauei from the intestine. Despite the spore length and polar capsule length of the current specimen larger than those of T. kitauei from the intestine, ranges of dimensions overlap, which is more suggestive of intraspecific variation than distinct species. BLAST search revealed that the present small subunit ribosomal DNA gene sequence is identical to those of T. kitauei. Histologically, most of spores distributed in the stratum spongiosum of dermis, and some spores in the strata compactum of host skin were also observed. Above all, both morphology and molecular analysis indicated that the current species from the skin of common carp is conspecific with T. kitauei from the intestine of carp and organ habitats transfer of T. kitauei from host intestine to skin may have occurred.

Health risk assessment of trace elements in two fish species of Sanandaj Gheshlagh Reservoir, Iran

The main purpose of this study was to determine heavy metal levels (Cd, Pb, Cr, Cu, Ni, Zn, and Fe) in the edible muscle, gill, liver, and skin of common carp (Cyprinus carpio) and silver carp (Hypophthalmichthys molitrix), in Sanandaj Gheshlagh Reservoir (SGR), Iran to evaluate their hazard levels in relation to the maximum residual limits for human consumption. The results indicated that Fe accumulated the highest level of metal in the organs of both fish species. Moreover, the highest and lowest level of metals has been accumulated in the gill and skin organs respectively. The statistical analysis indicated that the metal concentrations differed significantly among liver, gill, edible muscle, and skin in C. carpio and H. molitrix. Furthermore, the results of this study showed that the maximum allowable fish consumption rate for an adult person with mean 71.5 kg body weight were 2128, 136, 638, 1280, and 1124 g/day based on g/day based on Cd, Cu, Cr, Zn, and Fe levels respectively. In conclusion, results showed that the metal concentrations in the edible muscle of both fish species are below levels of concern for human consumption.

Bioaccumulation of mercury in some organs of two fish species from the Sanandaj Gheshlagh Reservoir, Iran

The purpose of this study was to monitor the concentrations of mercury in the edible muscle, gill, liver, and skin of common carp (Cyprinus carpio) and silver carp (Hypophthalmichthys molitrix), in the Sanandaj Gheshlagh Reservoir, Iran. Mercury concentrations were assayed using Shimadzu AA 6600 atomic absorption spectrophotometer, and the results were given as µg/g wet weight. The level of mercury in organs of silver carp was higher than in common carp. Moreover, the highest and lowest level of mercury has been accumulated in the gill and skin organs respectively. The results showed that the maximum allowable fish consumption rate for an adult person with mean 71.5 kg body weight were 21 g/day base on g/day based on mercury levels. In conclusion, results showed that the mercury concentrations in the edible muscle of both fish species are below levels of concern for human consumption.

Comparative transcriptome analysis reveals the genetic basis of skin color variation in common carp.

BackgroundThe common carp is an important aquaculture species that is widely distributed across the world. During the long history of carp domestication, numerous carp strains with diverse skin colors have been established. Skin color is used as a visual criterion to determine the market value of carp. However, the genetic basis of common carp skin color has not been extensively studied.Methodology/Principal FindingsIn this study, we performed Illumina sequencing on two common carp strains: the reddish Xingguo red carp and the brownish-black Yellow River carp. A total of 435,348,868 reads were generated, resulting in 198,781 assembled contigs that were used as reference sequences. Comparisons of skin transcriptome files revealed 2,012 unigenes with significantly different expression in the two common carp strains, including 874 genes that were up-regulated in Xingguo red carp and 1,138 genes that were up-regulated in Yellow River carp. The expression patterns of 20 randomly selected differentially expressed genes were validated using quantitative RT-PCR. Gene pathway analysis of the differentially expressed genes indicated that melanin biosynthesis, along with the Wnt and MAPK signaling pathways, is highly likely to affect the skin pigmentation process. Several key genes involved in the skin pigmentation process, including TYRP1, SILV, ASIP and xCT, showed significant differences in their expression patterns between the two strains.ConclusionsIn this study, we conducted a comparative transcriptome analysis of Xingguo red carp and Yellow River carp skins, and we detected key genes involved in the common carp skin pigmentation process. We propose that common carp skin pigmentation depends upon at least three pathways. Understanding fish skin color genetics will facilitate future molecular selection of the fish skin colors with high market values.

Cyprinid herpesvirus 3 infection disrupts the skin barrier of common carp (Cyprinus carpio L.)

Cyprinid herpesvirus-3 (CyHV-3) is recognised as a pathogen which causes mass mortality in populations of carp, Cyprinus carpio. One of the characteristic symptoms of the disease associated with CyHV-3 infection is the occurrence of skin lesions, sloughing off the epithelium and a lack of mucus. Furthermore, fish then seem to be more susceptible to secondary infections by bacterial, parasitic or fungal pathogens which may cause further mortality within the population. The observed pathological alterations lead to the assumption that the carp skin barrier is strongly challenged during CyHV-3 associated disease. Therefore we examined mRNA expression of genes encoding inflammatory mediators, type I interferons, and the following skin defence molecules: antimicrobial peptides, claudins, and mucin. In addition, we monitored changes in the bacterial flora of the skin during disease conditions.Our results show that CyHV-3 associated disease in the skin of common carp leads to a reduction in mRNA expression of genes encoding several important components of the mucosal barrier, in particular mucin 5B, beta defensin 1 and 2, and the tight junction proteins claudin 23 and 30. This caused changes in the bacterial flora and the development of secondary bacterial infection among some individual fish.To our knowledge this is the first report showing that under disease conditions associated with virus infection, the mucosal barrier of fish skin is disrupted resulting in a higher susceptibility to secondary infections. The reported clinical signs of CyHV-3 skin infection can now be explained by our results at the molecular level, although the mechanism of a probable virus induced immunomodulation has to be investigated further.

A comparative study on the physical, chemical and functional properties of carp skin and mammalian gelatins.

Carp species forms the bulk of the aquaculture production in India and studies have shown that the filleting waste of these species, particularly skin can be a good source of gelatin. This study is a comparison of the gelatins from these unexploited sources with that of mammalian gelatins to get a better understanding of their physicochemical and functional properties with respect to mammalian gelatins. The study showed that mammalian gelatins had significantly superior physical properties viz., higher viscosity, melting & setting temperature and faster setting time. The odour scores were significantly higher (P < 0.05) for bovine and porcine skin gelatins (3.1-3.12), indicating that they had a distinguishable odour and hence can be considered as inferior to fish skin gelatins in organoleptic qualities. The gel strengths of rohu and common carp skin gelatins were significantly lower than mammalian gelatins. Among the carp skin gelatins, grass carp skin gelatin was found to have better compatibility with gelatin from bovine and porcine skins.

PREPARATION AND CHARACTERIZATION OF GELATIN EXTRACTED FROM THE SKINS OF ROHU (LABEO ROHITA) AND COMMON CARP (CYPRINUS CARPIO)

ABSTRACT Gelatin was extracted from the skins of rohu and Common carp, and its physicochemical properties were studied. The yield of gelatin obtained from the skin of rohu and Common carp were 12.93 and 12%, respectively. The corresponding viscosity values were 6.06cP and 5.96cP. Rohu and Common carp skin gelatin had high content of imino acids i.e., 20.49 and 19.16%, respectively. Rohu gelatin had a significantly higher (P < 0.05) melting point than that of Common carp skin gelatin. The setting temperature observed for the gels from rohu and Common carp was 18.52 and 17.96C, respectively. Rohu and Common carp skin gelatins were found to have a mild but easily perceivable odor. The gelatins from the skin of rohu and common carp had a snowy white appearance and were light-textured. Rohu skin gelatin had significantly higher gel strength compared with Common carp skin gelatin. Foam formation ability and form stability of Common carp gelatin was significantly lower (P < 0.05) than that of Rohu gelatin. Rohu skin gelatin had the high fat-binding capacity. In this study, the functional properties observed for gelatins from the skin of rohu and Common carp are similar, if not better than many of the gelatins from other fish sources, and can be used as potential substitutes for the same in many applications. PRACTICAL APPLICATIONS Among the cultured carps, rohu (Labeo rohita) and Common carp (Cyprinus carpio) contribute significantly to the Aquaculture production in India. These species are presently being increasingly used for the preparation of mince and fillet-based value added products, with skin forming a major portion of the fishery waste thus generated. Hence, based on the availability and commercial importance and with the objective of efficient utilization of fish skin waste, these species were chosen for studies on gelatin extraction. It was observed that the physicochemical and functional properties for rohu and Common carp skin gelatins are similar, if not better than many of the gelatins from other fish sources and can be used as potential substitutes for the same in many applications. There is a future scope for developing binary blends of these gelatins with animal gelatins that are completely compatible and commercially useful in many applications.

Physical, Mechanical, and Barrier Properties of Carp and Mammalian Skin Gelatin Films

Films of 0.11 to 0.13 mm thickness were prepared using gelatins from the skins of cultured freshwater carp species and mammalian gelatins viz., porcine and bovine skin gelatin. A comparative study was made on the physical, mechanical, and barrier properties of these films. The amino acid composition, gel strength, clarity, and gel setting point of the gelatins were also determined. Carp skin gelatins had a lower imino acid content (19.16% to 20.86%) than mammalian skin gelatins (22.91% to 23.7%). Grass carp gelatin had gel strength of 230.2 B that is comparable to the reported value for bovine skin gelatin (227.2 B). The bloom values of rohu and common carp skin gelatins were 188.6 B and 181.3 B, respectively, which were significantly lower than mammalian gelatins. Mammalian gels have significantly higher (P < 0.05) setting temperatures (23.7 to 24.2 °C) than carp skin gelatins. Tensile strength (TS) was lowest for films from common carp and rohu skin gelatin (490 and 497 kg/cm(2), respectively) and highest for porcine skin gelatin film. The degree of transparency (L*) was significantly higher for films from grass carp, bovine hide, and pork skin gelatin films. Carp skin gelatin films had significantly lower water vapor permeability (WVP) and oxygen permeability (OP) than mammalian skin gelatin films, which indicated that carp skin gelatin based films have superior barrier properties than mammalian skin gelatin films.

Expression of the polymeric Immunoglobulin Receptor (pIgR) in mucosal tissues of common carp ( Cyprinus carpio L.)

The mucosal immune system seems to be an important defence mechanism for fish but the binding of IgM in mucosal organs is poorly described in fish. In this study the gene encoding the polymeric Immunoglobulin Receptor (pIgR) in carp has been isolated and sequenced from a liver cDNA-library and aligned with other species. The pIgR of carp consists of 2 Ig domains, a transmembrane and an intracellular region, together 327 amino acids. In situ hybridisations with sense and anti-sense DIG-labelled pIgR RNA probes were performed on liver, gut and skin of common carp ( Cyprinus carpio L.) and in these organs only anti-sense probes were found to hybridise. In liver the majority of hepatocytes was stained around the nucleus. In gut and skin, staining could be detected around the nucleus of the epithelial cells, but in gut also a subpopulation of lymphoid cells was stained in epithelium and lamina propria. The specific in situ hybridisation of the epithelia and hepatocytes coincides with the in situ binding of FITC-labelled carp IgM to the same cells. RT-PCR results indicate the expression of the pIgR gene in all lymphoid organs of carp, but not in muscle. Macrophages/neutrophils enriched by adherence or sorted B cells (MACS) did not show expression of the pIgR gene and are excluded as the pIgR expressing lymphoid cells in the intestine. The relevance of pIgR staining and gene expression in mucosal organs is discussed.

Corticotropin-releasing hormone-receptor 1 (CRH-R1) and CRH-binding protein (CRH-BP) are expressed in the gills and skin of common carpCyprinus carpioL. and respond to acute stress and infection

We established that corticotropin-releasing hormone (CRH), CRH-binding protein (CRH-BP) and CRH-receptor 1 (CRH-R1) are expressed in the gills and skin of common carp Cyprinus carpio, an early vertebrate. Immunoreactive CRH was detected in macrophage-like cells in gills and skin, in fibroblasts in the skin and in endothelial cells in the gills. The involvement of the CRH system in gills and skin was investigated in response to infection and in an acute restraint stress paradigm. Carp were infected with the protozoan leech-transmitted blood flagellate Trypanoplasma borreli and subjected to acute restraint stress by netting for 24 h. The expression of CRH-BP and CRH-R1 genes in the gills and in the skin is downregulated after both infection and restraint. Thus the peripheral CRH system reacts to infection and stress. The gills and skin separate the internal from the external environment and are permanently exposed to stress and pathogens. Because of their pivotal role in maintaining the homeostatic equilibrium, these organs must act locally to respond to diverse stresses. Clearly, the CRH system is involved in the response of the integument to diverse stresses at the vulnerable interface of the internal and external milieu.

Absorption of polychlorinated biphenyls (PCB) through gills and skin of common carp, Cyprinus carpio L

Absorption of polychlorinated biphenyls (PCB) through gills and skin of common carp, Cyprinus carpio L