Tissues Of Carp Research Articles

Oral immunization with recombinant Lactobacillus casei expressing flaB confers protection against Aeromonas veronii challenge in common carp, Cyprinus carpio

Aeromonas veronii is an important type of gram-negative pathogen of human-livestock-aquatic animal and causes great economic losses in the aquaculture industry. Vaccination is an effective method of defence against A. veronii. There are many factors that restrict the use of vaccination, and the development of new oral vaccines is urgently needed. The selection of suitable antigens is of great significance for the development of aquaculture vaccines. Bacterial flagellin can specifically bind to TLR5 and induce the release of cytokines from the organism, which could be used in the development of vaccines. In this study, we constructed two recombinant Lactobacillus casei (L. casei) (surface-displayed or secretory) expressing the flaB of A. veronii and evaluated the effect of immune responses in common carp. The flaB gene (900 bp) of A. veronii was subcloned into the L. casei expression plasmids pPG-1 (surface-displayed) and pPG-2 (secretory). Western blot and immunofluorescence assays confirmed the expression of the recombinant flaB protein. Common carp immunized with Lc-pPG-1-flaB and Lc-pPG-2-flaB via oral administration route exhibited induction of antibody expression and innate immune responses. The results indicated that Lc-pPG-1-flaB and Lc-pPG-2-flaB can induce high levels of IgM, ACP, AKP, LZM and SOD activity in organisms, and Lc-pPG-1-flaB can induce even higher levels. The recombinant L. casei may effectively induce humoral immunity and increase the serum immunological index. Furthermore, leukocytes phagocytosis percentage and index of the recombinant L. casei were enhanced. The results of qRT-PCR showed that recombinant L. casei can significantly increase the expression of IL-10, IL-β, IFN-γ and TNF-α in the tissues of immunized common carp, compared with control groups. Viable recombinant L. casei strains, which were delivered directly survived throughout the intestinal tract. Common carp that received Lc-pPG-1-flaB (66.7%) and Lc-pPG-2-flaB (53.3%) exhibited higher survival rates than the controls after challenge with the pathogen A. veronii. Our work indicated that Lc-pPG-1-flaB and Lc-pPG-2-flaB had beneficial effects on immune response and enhanced the disease resistance of common carp against A. veronii infection. The combination of flaB delivery and the Lactic acid bacteria (LAB) approach may be a promising method for the development of oral vaccines for treating A. veronii. In future research, we will focus on the colonization ability of LAB in the intestines and on the impact of these bacteria on intestinal flora.

Element Contents in Muscle Tissue of Prussian Carp from Different Lakes in an Urban Area

The aim of this study was to determine the content of some elements (Pb, Cd, Hg, Fe, Cu, Zn, As) in muscle tissue of Prussian carp (Carassius auratus gibelio) from seven different lakes in the Belgrade region, Serbia. Concentrations of Pb, Hg and As in fish muscle tissues from all examined lakes were under the maximum residual levels prescribed by the European Union (EU) and the maximum allowed concentrations (MAC) for Serbia. In all investigated fish, levels of Cd exceeded maximum allowed concentrations (0.05 mg kg-1). Data on the finding of elements in fish speak concurrently about the safety of fish as food and are good indicators of environmental pollution.

Seasonal Dynamics of Herbicides' Toxic Impact on Activity of Enzymes of Terminal Gluconeogenesis Reactions and Glucose Content in Carp Tissues

Changes in activity of the terminal gluconeogenesis enzymes and glucose content in liver, muscle and brain of the two-year-old carp (Cyprinus carpio L.) under the impact of pesticides zenkor and 2,4-DA were studied.

ОСОБЕННОСТИ ТЕХНОЛОГИИ ФАРШИРОВАННОГО РЫБОРАСТИТЕЛЬНОГО ПРОДУКТА, ОБОГАЩЕННОГО СО2-ЭКСТРАКТАМИ

The article presents the results of technological and merchandising research on the development of formulations of frozen semi-finished products from sweet pepper stuffed with minced fish, bulgur, quinoa and couscous, enriched by CO2-extracts with spices and smoking preparation. Feasibility of making frozen semi-finished products from fish is confirmed by an increase in consumer demand for these products, besides, shock freezing of semi-finished products with liquid nitrogen helps to preserve the most valuable components of the original animal and plant raw materials. The technology of cooking stuffed pepper from zoned raw materials is presented: sweet pepper sorts “Pride of Russia”, “Yellow Bull”, “Topolyn” grown in the open ground of the environmentally friendly Novopokrovsky district of the Krasnodar region by experts of the company “Vegan Line”, and muscle tissue of grass carp migrated from the Far East, acclimatized in the water bodies of Kuban and the Astrakhan region. For the first time in technological practice there the wheat grain modified products - bulgur and couscous with biologically active substances have been added to minced meat. A detailed analysis of chemical composition of pepper sorts mixture and grass carp caught in the Anapa district of the Krasnodar region was performed. In the course of studying the chemical composition of bulgur, quinoa and couscous there was stated a high content of alible proteins, vitamins, macro- and microelements. There have been formulated three recipes of stuffed sweet pepper of yellow, green and red colors: with bulgur, couscous and quinoa. A hardware-technological scheme has been developed for producing semi-finished sweet pepper stuffed with minced fish, cereals and CO2-extracts of spices and smoke preparation. There has been analyzed the chemical composition of the finished semi-finished products, provides information about the nutritional and biological value of the product, indicating a higher content of basic food and biologically active substances.

Temporal-spatial characteristics of lipea gene expression in Cyprinus carpio and its correlation with fat deposition

PDF HTML阅读 XML下载 导出引用 引用提醒 鲤lipea基因表达的时空特征及与脂肪沉积相关性分析 DOI: 作者: 作者单位: 1. 上海海洋大学, 农业农村部淡水水产种质资源重点实验室, 上海 201306;2. 中国水产科学研究院黑龙江水产研究所, 淡水鱼类育种国家地方联合工程实验室, 黑龙江 哈尔滨 150070 作者简介: 党红阳(1995-),女,硕士研究生,研究方向为水产生物技术.E-mail:danghongyang95@163.com 通讯作者: 中图分类号: S965 基金项目: 国家自然科学基金项目（31302174）；中国水产科学研究院基本科研业务费（2015C04XK01）；国家水产种质资源共享服务平台项目（2018DKA30470）. Temporal-spatial characteristics of lipea gene expression in Cyprinus carpio and its correlation with fat deposition Author: Affiliation: 1. Key Laboratory of Freshwater Fishery Germplasm Resource, Ministry of Agriculture and Rural Affairs;Shanghai Ocean University, Shanghai 201306, China;2. National Local Joint Engineering Laboratory for Freshwater Fish Breeding, Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin 150070, China Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:本文旨在克隆鲤（）基因，探究其时空表达特征及其与脂肪沉积的关系，以期为鲤脂肪沉积分子调控机制研究奠定理论基础。本实验采用RACE技术克隆获得鲤基因，其cDNA全长为3379 bp，包括230 bp的5'非翻译区（5'-UTR）、1067 bp的3'非翻译区（3'-UTR）和编码693个氨基酸的开放阅读框。多序列比对显示，鲤Oncorhynchus mykiss）的氨基酸序列相似性分别为88.17%、64.94%和63.35%，不同物种间序列差异主要集中在C-端的多肽序列上。蛋白质结构分析显示该蛋白含有3个功能域分别具有脂肪酶活性、乙酰基水解酶活性和水解酶活性。应用实时荧光定量PCR技术分析了在各组织中均有表达，腹腔脂肪中相对表达量最高，其次是腹部肌肉，血液中最少。随着胚胎的发育，表达量与背部肌肉脂肪含量呈正相关，但差异不显著（基因对鲤腹腔脂肪沉积可能具有抑制作用。本实验结果可为进一步解析鲤基因的功能和基因调控脂肪沉积分子机制研究提供参考。 Abstract:The objectives of this study were to investigate the expression pattern of Cyprinus carpio), to lay the foundation for studying and understanding the molecular regulation mechanism of fat deposition in common carp. In this study, a full-length cDNA sequence of gene in common carp was cloned by reverse transcription PCR and rapid-amplification of cDNA ends (RACE) technology, and the expression pattern of gene in different tissues of common carp and during its different developmental stages. cDNA of the gene of common carp was 3379 bp, with an open reading frame of 2079 bp, 5' untranslated region was 230 bp, 3' untranslated region was 1067 bp, encoding 693 amino acids. Multiple sequences alignment revealed that the amino acid sequences of Paralichthys olivaceus, and , respectively. It was determined that the sequence differences were mainly concentrated on the C-terminal polypeptide sequence between different species, and the structural analysis of proteins showed that the protein contains three functional domains with lipase activity, acetyl hydrolase activity, and hydrolase activity, respectively. Real-time quantitative PCR showed that the gene was expressed in all tested tissues, and the relative expression level was the highest in visceral fat, followed by abdominal muscles, and lowest in the blood. Its expression declined during the development of embryo; it was the highest in the 8-cell stage, followed by the late blastula stage. It was the lowest in the feeding period. The mRNA expression in different fat tissues negatively correlated with adipose tissue in the abdominal cavity; the highest and the lowest expression levels differed significantly (<0.01). The expression also positively correlated with dorsal muscle but it was not significant ( gene highlights its function and molecular regulation mechanism of fat development in common carp. 参考文献 相似文献 引证文献

Hematological Parameters and Ultrastructure of Hematopoietic Tissues in Common Carp (Cyprinus carpio L.) Exposed to Sublethal Concentration of Pendimethalin

Hematological Parameters and Ultrastructure of Hematopoietic Tissues in Common Carp (<i>Cyprinus carpio</i> L.) Exposed to Sublethal Concentration of Pendimethalin

Characteristics of the polymeric immunoglobulin receptor (pIgR) of commercial grass carp and the immune response of pIgR and immunoglobulin to Flavobacterium columnare

The transcytosis of polymeric immunoglobulins is primarily regulated by the polymeric immunoglobulin (pIg) receptor (pIgR), which can activate the host immune system and protect against pathogen invasion. To improve understanding of the immune defense of teleost fish, in this study for the first time the full-length complementary DNA (cDNA) sequence of the pIgR in grass carp Ctenopharyngodon idellus was cloned and characterized; its messenger RNA (mRNA) expression and molecular functions were also investigated. We determined that the complete sequence of the pIgR cDNA has 1640 nucleotides, which includes a 1011-base pair (bp) open reading frame, a 68-bp 5′ untranslated region (UTR), and a 561-bp 3′ UTR. Similar to other teleost homologs, the grass carp pIgR gene encodes a 336-amino acid transmembrane protein that contains an extracellular region with two immunoglobulin-like domains, a transmembrane region, and an intracellular region. Reverse transcription-polymerase chain reaction revealed the presence of the pIgR in all tested tissues of grass carp, with the highest levels in skin, gill, intestine, and liver. In addition, the immune response to Flavobacterium columnare of the pIgR and its two ligands (IgM and IgZ) was investigated. The patterns of increase in IgM and IgZ mRNA translation were similar to that of the pIgR. These results should aid the development of novel strategies against fish diseases.

Measurement and prediction of bioconcentration factors of organophosphate flame retardants in common carp (Cyprinus carpio)

The increase in the production and usage plus the toxicity nature of organophosphate flame retardants (OPFRs) has become a concern. However, limited information is available about the bioaccumulation potential of OPFRs in fish. In this study, we determined the 96 h LC50 s, and evaluated the bioaccumulation potential of six most frequently reported OPFRs in gill, kidney, liver, and muscle tissues of common carp (Cyprinus carpio) for 48 d, and a quantitative structure-activity relationship (QSAR) model was developed to predict bioconcentration factors (BCFs) for the remaining 16 OPFRs. The BCFs and half-lives (t1/2) in the tissues ranged from 6.54 (Tris (2-chloroisopropyl) phosphate, (TCPP)) to 528.15 (Tris (2-ethylhexyl) phosphate (TEHP)), and 2.25–5.78 days, respectively. The tissue-specific concentration and BCFs values followed the order of liver > kidney ≥ intestine >> muscle. The proposed QSAR model with a high cross-validated value (Q2(cum)) of 0.930 and a correlation coefficient of 0.94 was obtained and was able to predict log BCF from parameters related to molar volume and isotropic average static field polarizability. The results show that the model has a high level of accuracy, making the proposed approach a suitable method for predicting the log BCF.

Assessment of Mercury Accumulation and Magnification in a Freshwater Food Chain: Sediment, Benthos and Benthivorous Fish

Background: Present study was conducted to measure the level of total mercury (tHg) in sediments, benthos and benthivorous fish (i.e., common carp) for determining Biota (Benthos)-Sediment Accumulation Factor (BSAF), as well as Biomagnification Factor (BMF) of tHg between two trophic levels of benthos and benthivorous fish caught from Sanandaj Gheshlagh Reservoir (SGR) in the west of Iran. Methods: Samples of sediments and benthos biomasses were collected from three sampling stations. Common carps were captured around the selected stations during July to December 2010. Results: Means accumulated tHg (±SE) in sediments, benthos masses and muscle tissue of common carp were 117.66±9.72, 94.3±5.02 and 233.21±20.67 ng g-1 dry weight, respectively. Means accumulated tHg in benthos masses and muscle tissue of the common carp during the studying months showed no significant differences (P&gt;0.05), while it was significantly differed in sediment samples (P&lt;0.05). Results showed that there were statistically significant differences between accumulated tHg between sediment and benthos mass samples collected from the study sites (P&lt;0.05). Conclusion: During the study, all calculated BSAF measurements were less than one, indicating transmission of mercury from sediment to benthos was not considerable. However, mercury BMFs was higher than one, denoting mercury biomagnification occurred from the benthos trophic level to the higher trophic level (i.e., common carp) in study site. Hence, the health considerations have to be taken in to the account for consumption of fishery products of SGR.

Concentrations of microcystins in the muscle and liver tissues of fish species from Koka reservoir, Ethiopia: A potential threat to public health

Herein, we report the presence and concentrations of three most common variants of microcystin (MC–LR, –RR and –YR) in the liver and muscle tissues of wild Nile Tilapia (Oreochromis niloticus), Common Carp (Cyprinus carpio) and African Sharp Tooth Catfish (Clarias gariepinus), which were collected from two study sites of the present study on Koka reservoir, Ethiopia. A total of 36 fish liver and 36 fish muscle samples were collected for six months. Microcystins (MCs) were quantified using LC-ESI-HRMS. The results show that MCs were found in most of the fish liver samples, while they were below the detection limit of the method of analysis used in the muscle samples. In addition to the three most common congeners of MCs, eight other microcystin variants and cylindrospermopsin were detected in the fish liver samples although further detailed study is needed. Among the three most common MC congeners, MC-LR was more prevalent than MC-RR and MC-YR in the liver samples of the three fish species. The highest MC concentration was found in Nile Tilapia collected in April (591.60 μg/g DW of MC-LR), whereas the lowest detected concentration was in Catfish collected in March (2.23 μg/g DW of MC-RR). The results of this study suggest that further intensive assessment and monitoring of the reservoir from different perspectives should be conducted in order to reduce the concentrations of the MCs and seek solutions to the potential public health risk. Moreover, this is the first study ever to report detailed quantification of MCs in fish liver and muscle samples collected from Ethiopia.

Subchronic toxicity and hepatocyte apoptosis of dietary olaquindox in common carp (Cyprinus carpio)

Olaquindox as one of the effective antimicrobial agents and growth-promoting feed additives, had been widely used in animal and fish production. However, few studies have been done to unveil its possible toxic effect and tissue injury on aquatic animal. In this study, the toxic effect and underlying mechanisms of olaquindox toxicity were investigated in common carp when feed with different doses of olaquindox for 90 days. The morbidity and mortality, pathological changes, hematology parameters, residue concentration in the tissues of common carp were assessed, hepatocyte apoptosis was detected through ultrastructural observation and flow cytometry methods. The results showed that the morbidity and mortality increased with the increasing dosages of dietary olaquindox, subchronic exposure to olaquindox caused remarkably pathological changes, including congestion and bleeding, intramuscular edema, vacuolar degeneration, degeneration and deformation in renal tubules architecture, respiratory epithelium fusion and intestinal epithelial microvilli disintegration. Besides, dietary olaquindox led to significant changes in blood biochemical parameters including red blood cell, hemoglobin, alanine aminotransferase and aspartate aminotransferase, an elevated residue concentration of olaquindox was detected in liver and kidney after exposure, hepatocyte apoptosis and necrosis were observed. Moreover, insulin-like growth factor I (IGF-I) mRNA level in liver was higher than normal level with the dose below 25 mg/kg olaquindox and was lower than normal level with the dose above 50 mg/kg. Our results demonstrated that dietary olaquindox may pose subchronic toxicity and residue in fish organs and provided scientific data for the safe application of olaquindox in fish.

The prediction of mercury bioavailability for common carp (Cyprinus carpio L.) using the DGT technique in the presence of chloride ions and humic acid

The ability of the DGT technique to predict Hg2+ bioavailability for input tissues (skin, gills, and scales) of common carp in the presence of chloride ions and humic acid (HA) was evaluated. The mercury accumulation by the DGT units and input tissues of carp decreased with an increasing concentration of chloride ions (29–180 mg L−1) and HA (0–5 mg L−1). In the presence of chloride ions and HA, statistically significant correlations (Pearson's correlation coefficients 0.731–0.954) were determined between the rate of mercury accumulation by input tissues of carp and the rate of mercury accumulation by the DGT units. The laboratory experiments suggest the possibility of using the DGT technique for predicting the mercury bioaccumulation in natural aquatic ecosystems instead of commonly used input tissues of fish.

Effects of 17á-ethinylestradiol-based contraceptives on ovarian tissue using histopathological examination and FSH, LH, CYP1A, and CYP3A expressions using qRT-PCR in the ovaries and brain tissues of common carp (Cyprinus carpio L.)

In this study, the main aim was to identify the effects of exposure to 17á-ethinylestradiol-based contraceptives on the ovaries and brain tissues of common carp. For this purpose, histopathological changes were evaluated in ovaries after 21 days of contraceptive exposure. In addition, the expression levels of the CYP1A, CYP3A, FSH, and LH genes were measured in contraceptive-exposed brain tissue and ovaries respectively, using qRT-PCR (p less than 0.05, p less than 0.01, and p less than 0.001, respectively). No histopathological lesions, including inflammation, degeneration, or necrosis in the evaluated ovarian tissue of common carp were found after both high and low levels of exposure to contraceptives. Therefore, it is concluded that these contraceptives were highly dangerous to the reproduction system of common carp; the accumulation of contraceptive waste in the water supply could adversely affect and threat the common carp population. This may indirectly also affect other animals.

Genome wide identification of taste receptor genes in common carp (Cyprinus carpio) and phylogenetic analysis in teleost

Taste receptors (TRs) are seven trans-membrane G protein-coupled receptors as well as the interface between internal and external milieus, which playing pivotal roles in nutrient identification and acquisition. To better understand the scope and function of tr gene family in common carp, one of the most economic and important breeding fish species, which has undergone an additional round of whole genome duplication (WGD), we characterized 13 tr gene homologues including eight type I and five type II taste receptor genes from common carp genome, which were more than any other teleosts. Phylogenetic and syntenic analysis revealed the evolution dynamics of tr gene family, which was highly conserved, though gene duplication and gene loss do exist recently. Furthermore, the motif and dN/dS analyses indicated that these receptors were under different negative selection pressure. Additionally, the gene expression divergences were observed in 12 health tissues of common carp, with a relatively high level in barbel and head kidney, demonstrating tissue-specific expression of tr genes in the tetraploidized genome. The overarching goals of this study were to identify the abundance of tr genes in common carp, compare the gene divergence among species with varied feeding habits and provide genomic resources for future studies on teleost taste sensation.

Monitoring changing cellular characteristics during the development of a fin cell line from Cyprinus carpio.

The establishment and in-depth characterization of a novel continuous cell line derived from fin tissue of common carp (Cyprinus carpio), CCApin, is reported. The cells of the cell line could be propagated in Leibovitz's L-15 medium containing 15% foetal calf serum and 0.5% carp serum for >150 passages during the last 24 months, with a stable fast growth. Furthermore, antibody staining indicated that cell types obtained in primary cultures, containing the epithelial stem-cell marker tumorprotein 63, were different from cells in long-term cell cultures, containing tight junction protein zona occludens 1 and cytokeratin 7. These observations suggest a switch of dominant cell types. Molecular analysis of gene expression profiles of caudal fin tissue and CCApin cells showed that genes relevant in epithelial cells but also in mesenchymal cells were expressed. However, during cultivation of CCApin a set of very steadily expressed, primarily mesenchymal genes like collagen 1 alpha 1, fibronectin or cadherin 2 was found. In summary, the long-term cell culture could be described as a stably growing epithelial population with some mesenchymal features. There are several application possibilities, especially for virus susceptibility studies, e.g. cyprinid herpesvirus-3 (CyHV-3). The study leads to a better understanding of molecular and physiological mechanisms of in vitro fish cell cultures.

Metal bioaccumulation in selected tissues of barb (Barbus sp.) and common carp (Cyprinus carpio, Linnaeus 1758) from the Keban Dam Lake, Turkey

The aquatic life has been negatively influenced by harmful effects of environmental toxic elements, including heavy metals. The elevated concentrations of metals may be harmful for aquatic animals and human health. Herein, the present study deals with assessment of the bioavailability of metals [cadmium (Cd), chrome (Cr), copper (Cu), zinc (Zn), iron (Fe), lead (Pb), manganese (Mn), mercury (Hg), nickel (Ni), and selenium (Se)] in organs such as muscle, gills, liver, kidney, and gonad of the commercially consumed Barbus sp. and Cyprinus carpio (Linnaeus, 1758) collected from Keban Dam Lake, eastern Turkey. The fish were captured from four different stations of Keban Dam Lake. Our results indicated that Fe and Zn concentrations were the highest in all tissues of two fish species while Cd concentrations were the lowest levels. In addition, detected metals accumulated in the muscle of common carp at higher levels compared to Barbus sp. The results from the present study also demonstrated significant variations and considerable differences in the concentrations of all 10 elements between the four stations and different fish tissues. Overall, the concentrations of detected metals in the muscle were many folds higher than the permissible level prescribed by some national and international legislation, which raises health risk concerns.

Effects of MCPA Herbicide on Hematological Parameters and Ultrastructure of Hematopoietic Tissues of Common Carp (Cyprinus carpio L.)

Effects of MCPA Herbicide on Hematological Parameters and Ultrastructure of Hematopoietic Tissues of Common Carp (<i>Cyprinus carpio</i> L.)

Evaluation of toxicity and biochemical effects of the Oxadiargyl in Common carp (Cyprinus carpio L.)

This study aimed to investigate the effects of sublethal concentrations of oxadiargyl herbicide on growth performance, serum biochemical parameters and liver histology of the common carp, Cyprinus carpio , during 30 days exposure period. Carp fingerlings were randomly divided into four duplicate groups. Experimental groups were exposed to the concentration of 0.1, 0.3 and 0.5 ppm of oxadiargyl, while the control group was kept in toxicant free. During the experiment, none of the control fish died. Weight gain and condition factor decreased, while food conversion ratio increased in fish exposed to 0.5 ppm of oxadiargyl. Exposure to oxadiargyl significantly increased serum ALT, AST and ALP, as well as glucose levels, while cholesterol, total protein and albumin were significantly decreased in the exposed fish groups depend on oxadiargyl concentrations and exposure time. Diffuse and focal necrosis mainly as perivascular necrosis fibrosis, increase in size and number of melanomacrophage centers, bile duct hyperplasia, hyperemia and hemorrhage, fatty changes in the hepatocytes, fibrocyte aggregation and focal inflammatory cells were also the histological le­sions observed in the liver of exposed fish. These results showed that oxadiargyl is highly toxic to common carp and had negative effects on the growth performance, serum biochemical parameters and the liver tissue of common carp.

The occurrence and distribution of hexabromocyclododecanes in freshwater systems, focusing on tissue-specific bioaccumulation in crucian carp

The occurrence and distribution of hexabromocyclododecanes (HBCDs) were investigated in freshwater, sediment, and selected crucian carp (Carassius carassius) tissues (muscle, liver, egg, and blood) to evaluate the potential for HBCDs bioaccumulation. The HBCDs concentration ranged from not detected to 0.35ng/L in freshwater, and from 0.037 to 35.4ng/g-dw in sediment. The highest HBCDs concentration was detected in crucian carp liver (5.14±8.15ng/g-ww), followed by egg (3.88±10.1ng/g-ww), blood (0.61±0.63ng/mL), and muscle (0.38±0.70ng/g-ww). In all crucian carp tissues, α-HBCD was the predominant stereoisomer, and the fraction of α-HBCD as a proportion of the total HBCDs in liver tissue (96%) was higher than that in egg tissue (79%). There was a positive correlation between the HBCDs concentration in crucian carp muscle and body size (p<0.01, Spearman). The biota–sediment accumulation factor (BSAF) (0.14) and bioconcentration factor (BCF) (137,000L/kg) values were estimated in crucian carp muscle using field-based data.

Response of gastrointestinal melatonin, antioxidants, and digestive enzymes to altered feeding conditions in carp (Catla catla).

The purpose of present study was to ascertain whether the response of gastrointestinal (gut) melatonin to altered feeding conditions was related to the levels of different antioxidants and digestive enzymes in the same gut tissues of a sub-tropical carp (Catla catla). Accordingly, the fish were subjected to food deprivation for 4 or 8days and separately to re-feeding for 4 or 8 or 12days after deprivation of food for 8days, and their gut tissue homogenates were used to measure the levels of melatonin, both enzymatic [superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione S-transferase (GST)] and non-enzymatic [reduced glutathione (GSH)] antioxidants, as well as different digestive enzymes (α-amylase, cellulase, protease, and lipase). Notably, the gut levels of melatonin, SOD, CAT, GPx, and GST underwent gradual increase with the progress of food deprivation, but a sudden fall after restoration of food supply for 4days and a rise thereafter. Conversely, the activity of all the digestive enzymes significantly decreased after deprivation of food, but started increasing when food supply was reinforced. Gut melatonin concentrations by showing a positive correlation with the titers of different antioxidants (in both food-deprived and re-fed fish groups) and a negative (in food-deprived fish) or a positive (in re-fed fish) correlation with the activity of each digestive enzyme underlined possible physiological interplay between them. Collectively, our findings lend support to the hypothesis that gut melatonin response to altered feeding conditions in carp might be associated with the oxidative status as well as the digestive functions of the gastrointestinal tissues itself.