魚類のアミラーゼ, α-およびβ-グルコシダーゼ, β-ガラクトシダーゼの分布

This study investigates acute toxicity and histological effects of Lindane insecticide on intestinal tissues of immature grass carp (Ctenopharyngodon idella). For these purposes, 105 fish were exposed to different concentrations of Lindane for 96h in 5 groups with 3 replications. Samples of intestinal tissues were prepared in both control and exposure groups during and after the toxicity test. Vaculation, necrosis, bleeding and epithelial degeneration were apparent in the intestine tissue of treated individuals. The LC50 96h of Lindane was 0.788ppm in the present study, also the results showed besides pesticide-induced lesions, symptoms of abnormal swimming, anxiety, tendency to swim near the surface, and death due to terminal toxicity with mouth widely open. The exposed fish were pale in color, showed oxygen deficit and severe respiratory problems. Overall, our results confirm the toxicity of different concentrations of Lindane insecticide affecting behavior, intestinal function and inducing tissue lesions of immature grass carp.

Phosphofructokinase family genes in grass carp: Molecular identification and tissue-specific expression in response to glucose, insulin and glucagon.

BackgroundMethionine is an essential amino acid for fish. The present study was conducted to investigate the effects of dietary methionine on growth performance, digestive and absorptive ability, as well as antioxidant capacity in the intestine and hepatopancreas of sub-adult grass carp (Ctenopharyngodon idella).ResultsDietary methionine deficiency significantly decreased percentage weight gain (PWG), feed intake, feed efficiency and protein efficiency ratio, as well as activities of hepatopancreatic glutamate-oxaloacetate transaminase and muscle glutamate-pyruvate transaminase in sub-adult grass carp (P < 0.05). Furthermore, methionine deficiency significantly reduced activities of trypsin, lipase and amylase in the intestine, Na+/K+-ATPase, alkaline phosphatase and γ-glutamyl transpeptidase in three intestinal segments, and creatine kinase (CK) in the proximal intestine (P < 0.05). However, an unexplained and significant increase in CK activity in the mid intestine was associated with dietary methionine deficiency. Malondialdehyde and protein carbonyl contents in the intestine and hepatopancreas were significantly increased by methionine deficiency (P < 0.05), whereas anti-hydroxyl radical capacity in the hepatopancreas and intestine, and anti-superoxide anion capacity in the intestine, were significantly decreased by methionine deficiency (P < 0.05). Moreover, methionine deficiency significantly decreased superoxide dismutase and glutathione reductase activities, glutathione contents in the hepatopancreas and intestine, as well as glutathione peroxidase activity in the intestine (P < 0.05), whereas it significantly increased activities of catalase in the hepatopancreas and glutathione-S-transferase in the hepatopancreas and intestine (P < 0.05).ConclusionsThe present results demonstrated that dietary methionine deficiency induced poor growth, and decreased digestive and absorptive function and antioxidant capacity in the hepatopancreas and intestine of sub-adult grass carp. Methionine requirements for sub-adult grass carp (450-1, 170 g) based on PWG, intestinal trypsin, and hepatopancreatic anti-hydroxyl radical activities were estimated to be 6.12 g/kg diet (21.80 g/kg protein), 6.99 g/kg diet (24.90 g/kg protein) and 5.42 g/kg diet (19.31 g/kg protein), respectively, in the presence of 1.50 g cysteine/kg (5.35 g/kg protein).

The presence of pesticides and their potential toxic effects on fish can pose a threat to aquatic ecosystems and human health. The present study aimed to evaluate the effect of commercial formulations of glyphosate (Roundup) on the survival rate, hematological parameters, and tissues (gills and liver) of juvenile grass carp (Ctenopharyngodon idella). For these purposes, we exposed the fish to 0, 50, 100, and 150 mL L−1 of Roundup for 96 hr. Results showed a significant correlation between the fish’s mortality rate and pesticide concentrations ( p &lt; 0.01 ); the LC50 96 hr of Roundup was 75.838 mL L−1 in the present study. The concentrations above 50 mL L−1 induced significant tissue lesions seen as lamellar aneurism, leukocyte infiltration, distal hyperplasia, cloudy swelling, macrophage aggregates, and necrosis in the gills and liver. We also reported a significant correlation between the severity of tissue damage and Roundup concentration. The hematocrit, hemoglobin, white, and red blood cell count significantly reduced after 96 hr of exposure to 100 and 150 mL L−1. The opposite trend was reported for concentrations of glucose, albumin, cholesterol, total protein, and triglycerides. Finally, the fish exposed to 100 and 150 mL L−1 of Roundup displayed some clinical signs, such as increasing operculum movement, darkening the skin, and swimming near the surface during the movement test. Overall, our results showed that concentrations of Roundup higher than 50 mL L−1 can induce various toxic effects and significantly reduce the survival chance of juvenile grass carp. Roundup altered fish behavior, tissue functioning, and biochemical processes. In this study, we provided some basic knowledge about the effects of a glyphosate-based herbicide on aquatic organisms and possible environmental management.

&lt;em&gt;Abstract&lt;/em&gt;.—Numerous natural resource agency and media reports have alleged that Asian carps were introduced into the wild through escapes from commercial fish farms. This chapter traces the chronology associated with importations of Asian carps to North America and discusses the likeliest pathways of their introduction to the wild. The U.S. Fish and Wildlife Service first imported an Asian carp species, grass carp &lt;em&gt;Ctenopharyngodon idella&lt;/em&gt;, in 1963. Since then, state and federal agencies, universities, and private fish farmers have interacted to import Asian carps, to develop production technologies, and to promote their use in both public and private sectors in a number of different states. These importations and stocking, whether in confinement or, in the case of the grass carp, sometimes in open waters, were purposeful and legal. Asian carps were introduced to take advantage of their unique food preferences (planktivory by silver carp &lt;em&gt;Hypophthalmichthys molitrix &lt;/em&gt;and bighead carp &lt;em&gt;H. nobilis&lt;/em&gt;, herbivory by grass carp, and molluscivory by black carp &lt;em&gt;Mylopharyngodon piceus&lt;/em&gt;). The first known accidental release of diploid grass carp was in 1966 by the U.S. Fish and Wildlife Service in Stuttgart, Arkansas. Other early reports of grass carp in the wild were from waters in Alabama, Georgia, and Florida. Grass carp were reported from the wild in 1970, 2 years before the first private hatchery received grass carp. By 1972, grass carp had been stocked in open water systems in 16 different states. Silver carp and bighead carp were first imported purposely by a commercial fish producer in Arkansas in 1973. All silver and bighead carps were transferred to the Arkansas Game and Fish Commission by March 1974 where they first successfully spawned silver carp and bighead carp later that year. The first report of silver carp in the wild was in Arizona in 1972, although strong evidence suggests that this may have been a misidentification, followed by reports in Arkansas in the wild in 1975. The Arkansas report occurred 2 years before bighead carp and silver carp were returned to private hatcheries for commercial production. By 1977, silver carp and bighead carp had been introduced to Alabama, Arizona, Arkansas, Illinois, and Tennessee. Research and stockings of silver carp and bighead carp were conducted by at least six state and federal agencies and three universities in seven states in the 1970s and 1980s. Public-sector agencies, which were successful in encouraging development and use of Asian carps that today are in commercial trade, are the likeliest pathways for the earliest escapes of grass carp, silver carp, and bighead carp.

Analytical methods of chloramphenicol in the aquaculture environment have been developed using high-performance liquid chromatography and liquid chromatography-tandem mass spectrometry. The contents of chloramphenicol were determined using high-performance liquid chromatography for sediment and liquid chromatography-tandem mass spectrometry for fish and water collected from a freshwater aquaculture pond in China. Chloramphenicol in the water and sediment were 112.3 ng/L and 0.1957 mg/kg, respectively. The chloramphenicol residues in 3 kinds of fish, including carp, chub and grass carp were different. Only the muscle and head of grass carp were under the minimum required performance limit (0.3 μg/kg) and were safe to eat. The chloramphenicol in other tissues of grass carp, carp and chub exceeded the minimum required performance limit. The highest content of chloramphenicol was in the branchia of carp and the lowest was in the head of grass carp. The results showed the chloramphenicol in the aquaculture environment was serious, although the government of China had banned the use of chloramphenicol in aquaculture a few years ago.

We have used MALDI-TOF-MSI in positive ion mode for the analysis of quinolones and sulfonamides in grass carps. A novel CHCA/PPD matrix was prepared and applied using a simple method to improve the analysis. Compared with the traditional matrix, CHCA/PPD significantly improved the detection intensity of quinolones and sulfonamides with better sensitivity (17.20%-94.30%) and reproducibility. For demonstration, this novel matrix was successfully applied to visualize enrofloxacin (ENR) in grass carp tissues, with the entire abundance differences clearly observed based on MALDI-MSI. The concentration levels in different tissues were determined, with a calibration curve of 10-2000 μg/ml (R2 > 0.993). This study was the first to introduce CHCA/PPD as a novel matrix, and the classical acid-base mixing was used to improve the ionization effect of the traditional matrix CHCA in MALDI. Based on CHCA/PPD, MALDI-MSI detected ENR in different grass carp tissues for the first time and realized the spatial distribution and concentration detection.

Transcriptomics analysis provides new insights into the fish antiviral mechanism and identification of interferon-stimulated genes in grass carp (Ctenopharyngodon idella)

BackgroundCold-active enzymes, sourced from cold-adapted organisms, are characterized by high catalytic efficiencies at low temperatures compared with their mesophilic counterparts, which have poor activity. This property makes them advantageous for biotechnology applications as it: (i) saves energy costs, (ii) shortens the times for processes operated at low temperatures, (iii) protects thermosensitive substrates or products of the enzymatic reaction, (iv) prevents undesired chemical transformations, and (v) prevents the loss of volatile compounds.ResultsA bglMKg gene that encodes a monomeric cold-active glycoside hydrolase family 1 enzyme with an apparent molecular mass of 50 kDa was isolated by the functional screening of a marine metagenomic library. The BglMKg enzyme was expressed in E. coli, purified by FPLC and characterized. The recombinant BglMKg could effectively hydrolyze various chromogenic substrates and β-linked oligosaccharides, and had remarkably high β-galactosidase, β-glucosidase and β-fucosidase activities. Because of the lack of information about the usefulness of β-fucosidases in industry, further characterization of the enzymatic properties of BglMKg was only carried out with substrates specific for β-glucosidase or β-galactosidase. The BglMKg had maximal β-galactosidase and β-glucosidase activities at approximately 40°C and 45°C, respectively. The optimum pH for β-galactosidase activity was 6.5, whereas the optimum pH for β-glucosidase activity was 7.5. In general, the enzyme was stable below 30°C and from pHs 6.0 to 8.0. The results of the kinetic studies revealed that BglMKg more efficiently hydrolyzed β-glucosidase substrates than β-galactosidase ones.ConclusionsBglMKg is a small, monomeric, cold-active β-glucosidase with additional enzymatic activities. It was efficiently expressed in E. coli indicating that BglMKg might be a candidate for industrial applications.

To determine the function relationship between fish yield and artificial enrichments, we have analyzed, primarily by the multiple regression methods, the data from Taoyuan Serviceman of Fish Propagation Administration. The independent variables were size of reservoirs, inherent production capacity, amount of super phosphate, night-soil, chicken-dung and grass. The dependent variables are the yields of silver carp, crucian carp, common carp, mud carp, bighead, grass carp, perch, catfish and total fish yield. The average of the total fish yield in the 44 reservoirs was 1557kg/ha/yr. The correlation between the total fish yield and inherent production capacity, and the four enrichments was significant at 1% level. The best equation to predict the total fish yield(Y)for any reservoirs is calculated to be Y=296.91+0.547X1+0.003X2+0.051X3, where X1 is inherent production capacity, X2 is night-soil and X3 is chicken dung, all variables in kg/ha/year. The equation indicates that84% of the variability in total fish yield of which 45% is due to inherent production capacity, 26% to night-soil and 13% to chicken dung.

Analysis of metabolic characteristics of highly resistant grass carp bred on the basis of constitutive expression level of innate immune molecules.

Decision letter for "Developing CHCA/PPD as a Novel Matrix for Enhanced MALDI‐MSI for Analysis of Antibiotics in Grass Carp Tissues"

Observations on feeding habits of fish in ponds receiving green and animal manures in Wuxi, People's Republic of China

IntroductionHeavy metals are ubiquitous environmental pollutants, and fish could be contaminated by these metals, potentially posing a threat to human health through the food chain. Understanding the accumulation of these metals in fish tissues is crucial for assessing the safety of consuming fish products.MethodsIn this study, the distribution of nickel (Ni), copper (Cu), zinc (Zn), cadmium (Cd), and lead (Pb) in tissues of eight fish species (Ctenopharyngodon idellus, Megalobrama amblycephala, Hypophthalmichthys molitrix, Hypophthalmichthys nobilis, Carassius auratus, Cyprinus carpio, Culter alburnus, and Lateolabrax japonicas) collected from the Baishazhou market with different trophic levels and habitat preference was investigated using inductively coupled plasma mass spectrometry (ICP-MS). The metal accumulation capacity of different fish tissues and species was assessed, and the metal pollution index (MPI) was calculated to evaluate the extent of metal accumulation ability in each species. Additionally, the health risk assessment was conducted to evaluate the potential threat to human health posed by consuming these fish species.ResultsThe levels of metals exhibited variation among different fish tissues and species, showing an order of Zn &amp;gt; Cu &amp;gt; Ni &amp;gt; Pb &amp;gt; Cd. In terms of tissues, fish head demonstrated a greater capacity for metal accumulation compared to the muscles. Regarding fish species, the extent of accumulation ability varied depending on the specific metal, exhibiting the following order according to MPI: H. molitrix (0.568) &amp;gt; C. auratus (0.508) &amp;gt; M. amblycephala (0.469) &amp;gt; C. idellus (0.336) &amp;gt; C. alburnus (0.315) &amp;gt; C. carpio (0.274) &amp;gt; L. japonicus (0.263) &amp;gt; H. nobilis (0.206). Furthermore, in accordance with the results of health risk assessment, there was no potential health risk associated with the consumption of these fish species, as all target hazard quotient (THQ) values (ranger from not detected to 0.192) were below 1, and the maximum hazard index (HI) value was observed in C. carpio (0.519 for adults, 0.622 for children).ConclusionThe findings of this study demonstrate the distribution of heavy metals in fish tissues and indicate there were no potential health risk associated with consuming these fish bought from the Baishazhou market.

The occurrence of heavy water blooms of cyanobacteria (blue-green algae, BGA) in surface water is receiving increasing attention world wide as a potential health concern. This is a serious water quality problem because many of the cyanobacterial species or strains are able to produce potent toxins. The most frequently reported cyanobacterial toxins are cyclic heptapeptide hepatotoxins, microcystins, isolated from several species of the freshwater genera Microcystis, Planktothrix (Oscillatoria), Anabaena and Nostoc. They are potent and specific inhibitors of the serine threonine family of protein phosphatases, especially PP1 and PP2A. In order to minimize public exposure to MCs, the World Health Organization (WHO) has set a provisional guideline value of 1 μg/L for MC-LR in drinking water and established the tolerable daily intake (TDI) for consumption of cyanobacteria products contends MCs (0.04 μg/kg/day). Aquatic animals could bioaccumulate microcystins(cyanobacteria hepatotoxins) and so, beyond water, the ingestion of contaminated food represents a human health risk. In order to evaluate the potential risk of their ingestion, this study was mainly investigated the residue levels and distribution features of microcystins in fish from eutrophicated Lake Dianchi, a hypertropic lake in Yunnan Province containing toxic cyanobacteria blooms all the year round. Samples of silver carp (Hypophthalmichthys molitrix), bighead carp (Aristichthys nobilis) and grass carp (Ctenopharyngodon idellus) were collected in the biomanipulation test area in Lake Dianchi respectively in April and September, 2003. Microcystins in different tissues were all analyzed by enzyme-linked immunosorbent assay (ELISA) and the concentration was expressed as microcstin-LR equivalent. The results showed that microcystins presented in all samples, mainly distributing in liver, kidney and digestive tracts, and little in the muscle and the non-digestive tract organs. Different residue levels of microcystins were obviously in different fishes. Concentrations of microcystins in liver and kidney, the target organs of silver carp as well as bighead carp were significantly higher than that in grass carp. On the other hand, the residue levels of microcystins were also changeable along with seasons. Concentrations of microcystins in fish samples in April were lower than that in September. Finally, the safety assessment of the microcystin in fish muscle was also evaluated. According to the standard recommended by WHO, we calculated that the concentration of microcystins in fish muscle of all samples were not above the limit for human consumption. Then, we simply concluded that microcystins in fish muscle had not yet endangered to the human health only existed in the potential health risks. &amp;nbsp;