Impact of different dietary lutein levels on growth performance, biochemical and immuno-physiological parameters of oriental river prawn (Macrobrachium nipponense).

A 56-day trial was conducted to evaluate the effects of dietary lutein pigment on growth, biochemical, and immuno-physiological parameters of the oriental river prawn. Prawns were fed five formulated diets containing different lutein levels, 0 (control), 50, 100, 150, and 200 mg/kg. Growth performance, except hepatosomatic index, was affected by different lutein levels, and biochemical parameters (urea, uric acid, glucose, creatinine, and triglycerides) decreased. However, high-density and low-density lipoprotein elevated significantly compared to the control treatment. Furthermore, calcium, phosphorus, and cholesterol did not show a significant difference. Hemato-immunological parameters (albumin, total protein, cortisol, lysozyme, phenoloxidase, total hemocyte count, granular cells, semi-granular cells, hyaline cells, alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase), and hepatopancreatic antioxidant statuses (total antioxidant capacity, superoxide dismutase, catalase, and malondialdehyde), were significantly affected; however, alkaline phosphatase and glutathione peroxidase were not affected by lutein treatments. By increasing dietary lutein levels, digestive enzyme activities, total bacteria count, total carotenoid content, significantly increased. Conversely, lactic acid bacteria were not affected. Overall, the research results demonstrated that adding 200 mg/kg of lutein to the diet improved growth performance, biochemical and immuno-physiological parameters of the oriental river prawn.

Ovarian development pattern and vitellogenesis of ridgetail white prawn, Exopalaemon carinicauda.

The ridgetail white prawn Exopalaemon carinicauda has the potential to be used as a model organism in crustacean research because it has a transparent body, available draft genome, and short life cycle. However, their ovarian development pattern remains unclear under laboratory culture conditions. This study investigated the changes of ovarian external feature, ovarian histology, gonadosomatic index (GSI), and hepatosomatic index (HSI), as well as the expression and localization of vitellogenin in the ovary and the hepatopancreas during the first ovarian development cycle of E. carinicauda under laboratory-reared condition. The results demonstrated that (1) the first ovarian development cycle of E. carinicauda could be divided into 5 different stages in which the ovary changes its color from white to yellow during the vitellogenesis process in parallel with increasing GSI. (2) After pubertal molt, most females reached ovarian stage II while the females reached stage V after premating molt. (3) During the ovarian development, GSI increased smoothly and HSI relatively stable during the period of stages I to IV, while GSI increased but HSI decreased significantly from stages IV to V. (4) In situ hybridization (ISH) revealed that EcVg was slightly expressed in the oocyte cytoplasm of previtellogenic oocytes. The positive signal was mainly detected in hepatopancreatic fibrillar cells, and a strong signal was found in the hepatopancreas at stage IV. Moreover, the expression level of EcVg-mRNA in the hepatopancreas is stage-specific, and the hepatopancreas contributes majority of vitellin precursor protein to support the ovarian development of E. carinicauda.

Quantitative determination of rifampicin in aquatic products by stable isotope-dilution high liquid chromatography-tandem mass spectrometry.

Rifampicin is a semi-synthetic broad-spectrum antibiotic obtained from rifamycin B. It is one of the most effective first-line antituberculosis drugs and is widely used in clinical practice. In the present study, we describe a rapid and sensitive method for the determination of rifampin in aquatic products by stable isotope-dilution high liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Samples were extracted with the acetonitrile, degreased by hexane, and then concentrated by nitrogen blowing. After separation using a C18 column with a mixture of acetonitrile and water as mobile phase, it was determined by HPLC-MS/MS using the stable isotope-dilution calibration method. The performance of our method was validated. The limit of detection was 0.25 µg kg-1 and the limit of quantification was 0.5 µg kg-1 . At the three spiked levels of 0.5, 1.0 and 5.0 µg kg-1 , the average recoveries of rifampicin in different aquatic products were between 75.28 and 107.6%, and the relative standard deviation ranged from 0.81 to 13.23%. This method was successfully applied for the determination of rifampin in different kinds of aquatic products and rifampicin residue was found in aquatic products obtained from markets in Beijing, China.

Chemical synthesis of N-glycosylated insulin-like androgenic gland factor from the freshwater prawn Macrobrachium rosenbergii.

Crustacean insulin-like androgenic gland factor (IAG) of Macrobrachium rosenbergii, a heterodimeric peptide having both four disulfide bonds and an N-linked glycan, was synthesized by the combination of solid-phase peptide synthesis and the regioselective disulfide formation reactions. The disulfide isomer of IAG could also be synthesized by the same manner. The conformational analysis of these peptides by circular dichroism (CD) spectral measurement indicated that the disulfide bond arrangement affected the peptide conformation in IAG. On the other hand, the N-linked glycan attached at A chain showed no effect on CD spectra of IAG. This is the first report for the chemical synthesis of insulin-like heterodimeric glycopeptide having three interchain disulfides, and the synthetic strategy shown here might be useful for the synthesis of other glycosylated four-disulfide insulin-like peptides.

Acidic electrolysed water delays browning by destroying conformation of polyphenoloxidase.

BACKGROUND: Browning frequently occurs at fruits, vegetables and aquatic products during storage, and it drastically reduces the consumer's acceptability, with considerable financial loss. The objective of this paper was to investigate the effects of acidic electrolysed water (AEW) technology on polyphenoloxidase (PPO), which is an essential enzyme for browning. RESULTS: AEW ice exhibited a good ability in delaying browning in shrimp. Kinetic study revealed that AEW exhibited the mixed type inhibition of PPO with a Ki value of 1.96 mmol L-1 . Moreover, both the circular dichroism spectrum and Fourier transform infrared spectroscopy analyses revealed that the α-helix in PPO decreased whereas random coil increased which indicates that PPO conformation was destroyed. CONCLUSION: Thus, this paper may provide a deeper understanding of the application of AEW technology for preventing browning in the food industry. © 2017 Society of Chemical Industry.

Molecular Cloning and Functional Characterization of a Hexokinase from the Oriental River Prawn Macrobrachium nipponense in Response to Hypoxia.

Metabolic adjustment to hypoxia in Macrobrachium nipponense (oriental river prawn) implies a shift to anaerobic metabolism. Hexokinase (HK) is a key glycolytic enzyme in prawns. The involvement of HK in the hypoxia inducible factors (HIFs) pathway is unclear in prawns. In this study, the full-length cDNA for HK (MnHK) was obtained from M. nipponense, and its properties were characterized. The full-length cDNA (2385 bp) with an open reading frame of 1350 bp, encoded a 450-amino acid protein. MnHK contained highly conserved amino acids in the glucose, glucose-6-phosphate, ATP, and Mg+2 binding sites. Quantitative real-time reverse transcription PCR assays revealed the tissue-specific expression pattern of MnHK, with abundant expression in the muscle, and gills. Kinetic studies validated the hexokinase activity of recombinant HK. Silencing of HIF-1α or HIF-1ß subunit genes blocked the induction of HK and its enzyme activities during hypoxia in muscles. The results suggested that MnHK is a key factor that increases the anaerobic rate, and is probably involved in the HIF-1 pathway related to highly active metabolism during hypoxia.

Magnetic Schiff's base sorbent based on shrimp peels wastes for consummate sorption of chromate.

Magnetic Schiff's base chitosan composite has been prepared starting from shrimp peels as a raw material. Chitosan extraction involved three main stages as preconditioning, demineralization deproteinization and deacetylation. Chitosan modification process took place through the reaction between chitosan and polymeric Schiff's base of thiourea/glutaraldehyde in the presence of magnetite. The synthetic hybrid composite was characterized by Fourier transform infrared spectroscopy and scanning electron microscopy-energy dispersive X-ray analyses and tested as sorbent for Cr(VI) recovery from aqueous solution. The performance of the sorbent was systematically evaluated by batch sorption experiments, followed by equilibrium and kinetic studies with different mathematical models. The isotherm study demonstrate that the sorbent achieved 99.1% (sorption capacity; 252.45 mg g-1) removal efficiency in Cr(VI) solution with concentrations up to 400 mg/L. Experimental data gave better mathematical fitting towards pseudo-second-order kinetic model and Langmuir isotherm model. The distribution coefficient was obtained at different temperatures and the thermodynamic parameters have been calculated: the sorption is endothermic, spontaneous and contributes to increase the randomness of the system. The sorbent could be recycled for three cycles of sorption/desorption.

Risk assessment of human exposure to polycyclic aromatic hydrocarbons via shrimp (Macrobrachium felicinum) consumption along the Imo River catchments, SE Nigeria.

Shrimp species (Macrobrachium felicinum) collected from estuarine mangrove area of the Imo River is an important route of exposure to polycyclic aromatic hydrocarbons (PAHs). The estuarine associated sediment (EAS) composited sample showed higher TPAH, ΣAlkyl, ΣPAHcarc and ΣPAHEPA concentrations (550.84, 172.36, 413.17 and 482.11 ng/g dry weight-dw) than their mean concentrations in shrimp samples (509.39 ± 354.21, 31.38 ± 18.49, 52.10 ± 1.35 and 460.06 ± 330.76 ng/g wet weight-ww), respectively. Among the individual PAHs congeners, phenanthrene was the dominant species detected in the EAS accounting for 21.02 % of the total PAH load and the decreasing order of 3- > 2- > 5- > 4- > 6-ring contamination was found. A different pattern predominated by naphthalene was observed for the shrimp species, suggesting that the organisms have different selectivity for a range of PAHs congeners. These variations may be attributed to different degree of bioavailability of these compounds, characteristic sandy lithology of the EAS and the protective capacity of soot particles associated with liquid fossil fuel combustion masking the uptake of high molecular weight PAHs by the organisms. Cancer risk associated with consumption of shrimps in the region was assessed using estimated daily intake (EDI) and compared with standards. The EDI values for naphthalene, benzo(a)pyrene and ∑PAHcarc were lower than the USEPA benchmarks and EFSA levels of concern values for adult and children population, suggesting low probability of developing cancer.

Multiresidue method for the quantitation of 20 pesticides in aquatic products.

As the consumption of aquatic products increased, the need for regulation of pesticide residues in aquatic products also emerged. Thus, in this study, a scheduled multiple reaction monitoring (sMRM) method employing a novel extraction and purification step based on QuEChERS with EDTA was developed for the simultaneous quantitation of 20 pesticides (alachlor, aldicarb, carbofuran, diazinon, dimethoate, dimethomorph, ethoprophos, ferimzone, fluridone, hexaconazole, iprobenfos, malathion, methidathion, methiocarb, phenthoate, phosalone, phosmet, phosphamidon, pirimicarb, and simazine) in aquatic products. Additionally, the present method was validated in the aspects of specificity, linearity (r ≥ 0.980), sensitivity (the limit of quantitation (LOQ) ≤ 5 ng/g), relative standard deviation, RSD (1.0% ≤ RSD ≤ 19.4%), and recovery (60.1% ≤ recovery ≤ 117.9%). Finally, the validated method was applied for the determination of the 20 pesticide residues in eel and shrimp purchased from local food markets. In the present study, QuEChERS with EDTA was successfully expanded to residual pesticide analysis for the first time. The present method could contribute to the rapid and successful establishment of the positive list system in South Korea.

A selective biomarker for confirming nitrofurazone residues in crab and shrimp using ultra-performance liquid chromatography-tandem mass spectrometry.

Reliably detecting nitrofurazone (NFZ) residues in farmed crab and shrimp was previously hindered by lack of appropriately specific analytical methodology. Parent NFZ rapidly breaks down in meat, and the commonly used side-chain metabolite, semicarbazide (SEM), is non-specific as it occurs naturally in crustacean shell often leading to 'false positive' detections in meat. Using 5-nitro-2-furaldehyde (NF) as marker metabolite, following pre-column derivatization with 2,4-dinitrophenylhydrazine (DNPH), ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) analysis in negative electrospray ionization mode enabled confirmation of NFZ residues in deliberately treated whole crab, crab meat and shrimp meat, with a limit of detection (LOD) and limit of quantification (LOQ) below 1 ng g(-1). Meanwhile, the derivatives of DNPH-NF were synthesized for the first time, purified by preparative liquid chromatography and structure characterized with nuclear magnetic resonance spectroscopy ((1)H-NMR). The purity of derivative was checked by ultra-performance liquid chromatography-tunable ultraviolet (UPLC-TUV), and the contents were beyond 99.9%. For comparison purposes, crustacean samples were analysed using both NF and SEM marker metabolites. NFZ treatment was revealed by both NF and SEM marker metabolites, but untreated crab also showed measurable levels of SEM which could potentially be misinterpreted as evidence of illegal NFZ use.

Uptake and depuration of PCB-153 in edible shrimp Palaemonetes varians and human health risk assessment.

A medium-term mesocosm exposure study was conducted to elucidate bioaccumulation and depuration of polychlorinated biphenyl congener 153 (PCB-153) in edible shrimp Palaemonetes varians. Over the 15-day exposure period, shrimp under different exposure concentrations exhibited a significant increase in PCB-153 concentration compared with control organisms. Distinct bioaccumulation patterns and uptake rates were observed depending on the exposure concentrations. For low PCB-153 exposure levels (0.25µgL(-1)), accumulation followed a saturation model, reaching an apparent steady state after fifteen days exposure. For intermediate (2.5µgL(-1)) and high PCB-153 levels (25µgL(-1)), accumulation was faster and linear. In addition, the bioaccumulation rate was not proportional to PCB-153 concentration, and the bioaccumulation was higher at intermediate exposure concentrations. Regarding the depuration phase, P. varians lost up to 30% of PCB-153 after 72h and levels continued slowly to decrease until the end of the 30-d experimental period. However, PCB-153 levels in shrimp did not reach background values, and those exposed to moderate and high PCB-153 concentrations presented contamination levels much higher than the regulatory limit for human food consumption (75ngg(-1) ww for Σ6 PCB).

Mitigation of mechanical damage and protein deterioration in giant river prawn (Macrobrachium rosenbergii) by multi-frequency ultrasound-assisted immersion freezing.

In order to investigate the effects of multi-frequency ultrasound-assisted immersion freezing (MUIF) on the meat quality of Macrobrachium rosenbergii, tail meat was subjected to different MUIF treatments respectively, namely 20 + 40 kHz (MUIF-20 + 40), 20 + 60 kHz (MUIF-20 + 60), 40 + 60 kHz (MUIF-40 + 60) and 20 + 40 + 60 kHz (MUIF-20 + 40 + 60), and the immersion freezing (IF) as control. Results showed that average diameter of ice crystals was 28 µm in IF, and that was only 8 µm in MUIF-20 + 40 + 60. When compared to IF, MUIF alleviated oxidative deterioration of lipids and proteins, but only at higher ultrasound frequency (MUIF-40 + 60; MUIF-20 + 40 + 60). Carbonyl content of MUIF-20 + 40 + 60 was only 40% of that in IF. Similarly, protein denaturation was inhibited in MUIF (except for MUIF-20 + 40). Transmission electron microscopy showed greater distortion of the ultrastructural components in IF, MUIF-40 + 60, and MUIF-20 + 40 + 60, suggested by bended Z-line. In conclusion, MUIF can be an effective strategy to mitigate mechanical damage and protein deterioration in the meat of Macrobrachium rosenbergii.

The differences of characteristics and allergenicity between natural and recombinant tropomyosin of Macrobrachium nipponense.

Tropomyosin (TM) is the main allergen of Macrobrachium nipponense. Recombinant allergens have great prospects in the detection, diagnosis, and treatment of food allergens. The purpose of this study was to compare the differences in structure and allergenicity between natural TM and recombinant TM. Recombinant TM of M. nipponense with a molecular weight of 38 kDa was successfully expressed in the Escherichia coli system. The amino acid sequence as well as secondary structure between natural and recombinant TM were similar, which were verified by mass and CD spectrometry, respectively. Studies showed that both natural TM and recombinant TM had strong allergenicity, and recombinant TM was more allergenic, which could be used as a substitute for natural TM in the diagnosis and treatment of shrimp allergy. This study provided stable and reliable allergen components for the detection of crustacean allergens and the diagnosis and treatment of food allergies caused by crustacean allergens.

F0ATP synthase b-chain of Litopenaeus vannamei involved in white spot syndrome virus infection.

White Spot Syndrome Virus (WSSV) is one of the most common and distrous diseases for shrimp. In this study, we show that the protein VP292 that is a envelop protein of WSVV interacts with F0ATP synthase b-chain from Litopenaeus vannamei using far-western blot, ELISA, and indirect immunofluorescence analysis. Tissue distribution analysis of F0ATP synthase b-chain showed that it's transcription can be detected in muscle, hepatopancreas, intestine, hemocytes, lymphoid, and gills. Cellular localization of F0ATP synthase b-chain in shrimp hemocytes showed that F0ATP synthase b-chain was primarily located in the cytoplasm of hemocytes. The transcription levels of F0ATP synthase b-chain were significantly upregulated in intestine, hepatopancreas, hemocytes, and gills of WSSV-infected shrimp at 12 h after infection. Far-western, ELISA, and indirect immunefluorescence assay indicated that F0ATP synthase b-chain interacted with VP292. In the in vivo neutralization experiment, F0ATP synthase b-chain attained 18% protection rate of the shrimp challenged by WSSV. To the best of our knowledge, this is the first report to show that F0ATP synthase b-chain is involved in WSSV infection.

Immunoaffinity column cleanup with LC/MS/MS for the determination of chloramphenicol in honey and prawns: single-laboratory validation.

A single-laboratory validation was conducted to establish the effectiveness of an immunoaffinity column (IAC) cleanup procedure followed by LC/MS/MS for the determination of chloramphenicol (CAP) in honey and prawns. Honey is dissolved in buffer solution and centrifuged, and an aliquot applied to an IAC. For prawns, a portion of the homogenized sample is shaken with buffer and centrifuged, and an aliquot similarly applied to an IAC. For both matrix extracts, CAP is removed from the IAC with neat methanol, then directly analyzed by electrospray LC/MS/MS in the negative ionization mode using m/z 321 as a precursor ion and m/z 257 and 152 as qualifier and quantifier ions, respectively. Test portions of blank honey and prawns were fortified with CAP to give levels of 0.3, 1.0, and 5.0 microg/kg. Recoveries of CAP on 3 consecutive days ranged from 83-103% for honey and 84-108% for prawns. Based on results for fortified blank matrixes (triplicate at three levels), the RSD for repeatability (RSDr) averaged 8.4% for honey and 4.8% for prawns. The method LOD was 0.05 for prawns and 0.16 microg/kg for honey, both well below the minimum required method performance limit for CAP. The accuracy of the method was demonstrated by participation in proficiency testing, where satisfactory Z-scores were obtained for CAP in incurred samples of both honey and prawns. The method was shown to be applicable to a wide range of other matrixes, including milk, egg, royal jelly, meat, and seafood products.

Bioaccessibility of total arsenic and arsenic species in seafood as determined by a continuous online leaching method.

A continuous leaching method coupled online with inductively coupled plasma mass spectrometry (ICP-MS) detection was used to assess the maximum bioaccessibility of arsenic (As) in seafood samples. The method simulates continuous-flow digestion by successively pumping artificial saliva, gastric and intestinal juices through a mini-column of powdered sample directly connected to the nebuliser of an ICP-MS instrument. The method allows the real-time measurement of As being released by a given reagent. Because the analyte is continuously removed from the system, in contrast to batch methods, the dissolution equilibrium is driven to the right, hence quickly providing information about the worst-case scenario. Following consecutive leaching by the digestive reagents, the leachates were subject to speciation analysis by ion-exchange chromatography with ICP-MS detection to determine the arsenic species released. Finally, the remaining residue from the mini-column was fully digested to verify mass balance. The method was used to determine the bioaccessibility of total As and As species in four certified reference materials and in several real seafood samples. The mass balance was verified in each case. Generally speaking, the non-toxic form was easily released whereas the inorganic forms were poorly bioaccessible.

Assimilation of elements and digestion in grass shrimp pre-exposed to dietary mercury.

Grass shrimp Palaemonetes pugio were fed mercury (Hg)-contaminated oligochaetes for 15 days and analyzed for Hg, cadmium (Cd), and carbon assimilation efficiencies (AE) as well as toxicological end points related to digestion. Disproportionate increases in stable Hg concentrations in shrimp did not appear to be related to partitioning to trophically available Hg in worms. Hg AE by pre-exposed shrimp reached a plateau (approximately 53 %), whereas Cd AE varied (approximately 40-60 %) in a manner that was not dose-dependent. Carbon AE did not differ among treatments (approximately 69 %). Gut residence time was not impacted significantly by Hg pre-exposure (grand median approximately 465 min), however, there was a trend between curves showing percentages of individuals with markers in feces over time versus treatment. Feces-elimination rate did not vary with dietary pre-exposure. Extracellular protease activity varied approximately 1.9-fold but did not exhibit dose-dependency. pH increased over the range of Hg pre-exposures within the anterior (pH approximately 5.33-6.51) and posterior (pH approximately 5.29-6.25) regions of the cardiac proventriculus and Hg assimilation exhibited a negative relationship to hydrogen ion concentrations. The results of this study indicate that previous Hg ingestion can elicit post-assimilatory impacts on grass shrimp digestive physiology, which may, in turn, influence Hg assimilation during subsequent digestive cycles.

Carbon assimilation and digestive toxicity in naïve grass shrimp (Palaemonetes pugio) exposed to dietary cadmium.

Naïve grass shrimp Palaemonetes pugio were pulse-fed cadmium-contaminated meals containing carbon-14, fluorescent or near-infrared markers and analyzed for carbon assimilation efficiency, gut residence time, feces elimination rate, extracellular digestive protease activity or gut pH. Carbon assimilation efficiency (~83%), minimum gut residence time (~435 min) and proventriculus pH (~5.29 to ~6.01) were not impacted significantly by cadmium ingestion. A dose-dependent decrease in feces elimination rate (from ~14.4 to ~6.4 mm h(-1)) was observed for shrimp for 2 h following minimum gut residence time. Protease activities increased ~2.4-fold over the range of dietary cadmium exposures, however, this variation was not dose-dependent. Differential impacts of cadmium exposure on carbon and cadmium assimilation reported previously are consistent with work involving shrimp subjected to chronic field exposure. The influence of ingested cadmium on feces elimination rate may be related to pre-assimilatory impacts on packaging, intestinal transport or release of feces. Protease activities may have been influenced by pre-assimilatory interactions between available cadmium ions in gut fluid and enzyme-secreting cells of the hepatopancreatic epithelium or direct impacts on active enzymes.

Fatty acids in an estuarine mangrove ecosystem.

Fatty acids have been successfully used to trace the transfer of organic matter in coastal and estuarine food webs. To delineate these web connections, fatty acid profiles were analyzed in species of microbes (Azotobacter vinelandii, and Lactobacillus xylosus), prawns (Metapenaeus monoceros and Macrobrachium rosenbergii) and finfish (Mugil cephalus), that are associated with decomposing leaves of two mangrove species, Rhizophora apiculata and Avicennia marina. The fatty acids, except long chain fatty acids, exhibit changes during decomposition of mangrove leaves with a reduction of saturated fatty acids and an increase of monounsaturated fatty acids. The branched fatty acids are absent in undecomposed mangrove leaves, but present significantly in the decomposed leaves and in prawns and finfish, representing an important source for them. This revealed that the microbes are dominant producers that contribute significantly to the fishes and prawns in the mangrove ecosystem. This work has proved the fatty acid biomarkers as an effective tool for identifying the trophic interactions among dominant producers and consumers in this mangrove.

Effect of protein oxidation and degradation on texture deterioration of ready-to-eat shrimps during storage.

The impact of protein oxidation and degradation on texture deterioration of ready-to-eat (RTE) shrimps during storage was investigated. The deterioration in texture during storage was manifested by decreased instrumental hardness, elasticity, chewiness, and recoverability. The occurrence of protein oxidation was revealed by a significant increase in the contents of free radicals and carbonyls. The increases in trichloroacetic acid-soluble peptide (TCA-soluble peptide) content and myofibril fragmentation index (MFI) were also observed, suggesting the degradation of protein. Pearson correlation analysis showed that the decreased instrumental texture parameters were negatively correlated with the increased carbonyl content, TCA-soluble peptide, MFI, porosity, and pore size as well as the decreased water-holding capacity (WHC), thus, it was hypothesized that protein oxidation and degradation were responsible for changes in the microstructure and reduction of WHC, which ultimately resulted in texture deterioration of RTE shrimps.