Shrimp Muscle Research Articles

Label-free based proteomics analysis of protein changes in frozen whiteleg shrimp (Litopenaeus vannamei) pre-soaked with sodium trimetaphosphate

Muscle proteins in peeled shrimp (Litopenaeus vannamei) are known to be unstable and prone to denaturation affected by freezing and frozen storage. In this study, label-free proteomics were performed to explore the stabilization of frozen (30 days at −18 °C) shrimp muscle proteins when a pre-soaking treatment with distilled water (DW)- or sodium trimetaphosphate (ST) was applied; comparison to fresh samples (FS) was carried out. In total, 163 differentially abundant proteins (DAPs) were down-regulated in DW batch when compared to FS, these including ribosomal proteins, actins, myosin, paramyosin, myosin heavy chains, and tropomyosin; interestingly, most of these DAPs (181 proteins) were up-regulated in ST batch when compared to DW shrimp, mainly due to the incorporation of ST into muscle tissues. The results revealed the decreased protein degradation resulting from the reduced damage from ice-crystal growth. Gene ontology (GO) analysis suggested that these DAPs were mainly involved in catalytic activity, binding, and metabolic processes. Kyoto encyclopedia of genes and genomes (KEGG) results indicated that many pathways, including phototransduction, metabolic, and ribosomal pathways that interacted with phosphoglycerate mutase, actins, and ribosomal proteins were altered. Additionally, Eukaryotic clusters of orthologous group (KOG) results confirmed that incorporated ST maintained the stability of these DAPs in shrimp muscle, especially for cytoskeleton proteins, and retarded the degradation of muscle proteins during frozen storage.

Multi-species transcriptomics reveals evolutionary diversity in the mechanisms regulating shrimp tail muscle excitation-contraction coupling.

The natural flight response in shrimp is powered by rapid contractions of the abdominal muscle fibres to propel themselves backwards away from perceived danger. This muscle contraction is dependent on repetitive depolarization of muscle plasma membrane, triggering tightly spaced cytoplasmic [Ca2+] transients and rapidly rising tetanic force responses. To achieve such high amplitude and high frequency of Ca2+ transients requires a high abundance of sarcoplasmic/endoplasmic reticulum Ca2+ ATPase (SERCA) to rapidly clear cytoplasmic Ca2+ between each transient and an efficient Ca2+ release system consisting of the Ryanodine Receptor (RyR), and voltage gated Ca2+ channels (CaVs). With the aim to expand our knowledge of muscle gene function and identify orthologous genes regulating muscle excitation-contraction (EC) coupling, this study assembled nine Penaeid shrimp muscle transcriptomes. On average, the nine transcriptomes contained 27,000 contigs, with an annotation rate of 36% and a BUSCO completeness of 70%. Despite maintaining their function, the crustacean RyR and CaV proteins showed evidence of significant diversification from mammalian orthologs, while SERCA remained more conserved. Several key components of protein interaction were conserved, while others showed distinct crustacean specific evolutionary adaptations. Lastly, this study revealed approximately 1,000 orthologous genes involved in muscle specific processes present across all nine species.

Regulation of growth, fatty acid profiles, hematological characteristics and hepatopancreatic histology by different dietary n-3 highly unsaturated fatty acids levels in the first stages of juvenile Pacific white shrimp (Litopenaeus vannamei)

An 8-week feeding experiment was conducted to investigate the effects of dietary n-3 highly unsaturated fatty acids (n-3 HUFAs) on growth performance, fatty acid profiles, hematological characteristics and hepatopancreatic histology in juvenile Pacific white shrimp (Litopenaeus vannamei) (initial average weight, 0.14 ± 0.01 g). Six isoproteic and isolipidic diets were formulated with graded levels of n-3 HUFA (0.24, 0.53, 0.86, 1.25, 1.58 and 1.97 % of dry matter), and the 0.24 % group was used as control group. The results revealed that shrimp fed the diet containing 0.86 % n-3 HUFA had highest weight gain (WG) and specific growth rate (SGR), and the feed conversion ratio (FCR) showed the minimum at the same level. Shrimp muscle fatty acid profiles reflected that of diet. The contents of triglyceride (TG) and low-density lipoprotein cholesterol (LDL-C) in serum decreased along with n-3 HUFA levels increasing. The activity of superoxide dismutase (SOD) in hepatopancreas was highest significantly at the level of 0.86 % n-3 HUFA group than that in other groups. The content of malondialdehyde (MDA) in hepatopancreas increased with the increasing of n-3 HUFA levels, which reached the maximum value in 1.97 % group and was significantly higher than that in control group. The levels of n-3 HUFA could obviously affect on the cell morphology and lipid deposition in hepatopancreas of L. vannamei. Results of this study suggested that shrimp fed moderate dietary n-3 HUFA could enhance growth, feed utilization, antioxidant capacity and reduces excess lipid deposition.

Characterization of lipid composition in the muscle tissue of four shrimp species commonly consumed in China by UPLC−Triple TOF−MS/MS

In this study, comprehensive lipid composition in the muscle tissue of four popularly consumed shrimp species was determined using ultra-performance liquid chromatography-triple time-of-flight tandem mass spectrometry (UPLC−Triple TOF−MS/MS). About 600 molecules from 14 types of lipids were characterized and quantified. Phospholipids (PLs) were the main component in all four shrimp species (51.4–71.0% of total lipids). Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) were the major PL subclasses (49.3–53.2% and 42.3–48.4% of total PLs). Triacylglycerol (TAG) and diacylglycerol (DAG) contents were relatively low (8.6–32.5% and 11.5–14.1% of total lipids). Docosahexaenoic acid (DHA, 22:6n-3), eicosapentaenoic acid (EPA, 20:5n-3) and arachidonic acid (AA, 20:4n-6) were dominant in free fatty acids (76.5–85.2%) and PL. Sphingolipid (SL) was detected in low content (<5% of total lipids). Using high throughput analytical method, detailed lipid composition in shrimp muscle were obtained, which could help to assess shrimp nutrition value and identify their species.

Trehalose and alginate oligosaccharides affect the stability of myosin in whiteleg shrimp (Litopenaeus vannamei): The water-replacement mechanism confirmed by molecular dynamic simulation

Myosin in shrimp (Litopenaeus vannamei) is prone to denaturation and is affected by freezing and frozen storage. Previous studies indicated that cryoprotective trehalose (TR) and alginate oligosaccharides (AO) greatly slowed the degradation of myofibrillar proteins and reduced mechanical damage on shrimp muscle tissues. In this study, homology modeling and 60 ns of molecular dynamic (MD) simulations were conducted in order to investigate the conformation variations of myosin in 0.03 g/mL TR and AO systems. Ramachandran plot for the myosin model established by Modeller program revealed that 91.9% of all amino acid residues were in the most favored regions. After MD simulations, it was found that the incorporated TR/AO were generally close to myosin and combined with amino acid residues via electrostatic interactions and hydrogen bonds. The combination of TR/AO replaced partial water molecules around myosin surface, thereby improving the cooperativity and consistency of the myosin heavy and light chain (MHC and MLC) motions. This decreased the flexibility of myosin chains and reduced the risk of protein aggregation, stabilizing the conformational structure of myosin in the systems. Finally, the water-replacement mechanism induced by TR/AO molecules was confirmed to predominantly contribute to the stability of shrimp myosin in the simulated systems.

Effects of High Pressure on Myofibrillar Protein and Moisture Distribution of Shrimp (Solenocera melantho) Muscle

ABSTRACTThe effects of high pressure (100–500 MPa) treatment on myofibrillar protein (MP) contents and distribution of water in Solenocera melantho muscle were investigated. The results showed that the shrimp treated with 200 MPa had the highest shelling score, and the solubility of MP in meat of shrimp treated with 300 MPa was significantly reduced. Moreover, the surface hydrophobicity of MP increased with increasing pressure. Treatment of shrimp with 200–300 MPa high pressure partially converted the structure of MP from an α-helix structure to a β-sheet structure, allowing for greater exposure of the tryptophan residues present. Treatment of shrimp with 100–200 MPa led to a significant loss in the amount of immobilized water in shrimp muscle. However, the treatment did not significantly change the moisture distribution. Overall, pressures of 100 to 200 MPa are considered the most suitable for the processing of S. melantho.

Validation of a Commercial ELISA Kit for Screening 3-amino-2-oxazolidinone, A Furazolidone Antibiotic Residue in Shrimp

Furazolidone, a banned nitrofuran antibiotic, is still illegally used in aquaculture and livestock husbandry. A commercial Enzyme-linked Immunosorbent Assay (ELISA) from Europroxima, The Netherlands is described, and validated for the screening of 3-amino-2-oxazolidinone (AOZ), metabolite of furazolidone antibiotic in the muscle of shrimp. Research works was conducted at Veterinary Drug Residue Analysis Laboratory, Institute of Food and Radiation Biology, Atomic Energy Research Establishment, Savar, Dhaka-1349, between July 2018 and December 2019. Validation was done in accordance with the European Commission (EC) decision 2002/657/EC in terms of specificity, detection capability CCβ, selectivity, ruggedness, and stability. Homogenized sample was subjected to acid hydrolysis for releasing of tissue bound metabolite AOZ, and derivatized with o-nitrobenzaldehyde followed by ethyl acetate/n-hexane extraction and detection by ELISA reader. The detection capability CCβ of the method was lower or at 0.3 µg/kg accepting 0% false compliant result. Cut-off factor Fm and the positivity threshold value T was 0.716 and 0.982, respectively. Mean OD of blank sample B was1.225. The assay was valid because T was greater than Fm and smaller than B. The kit was stable even after ten months of storage at recommended temperature and showed good sensitivity. From the practical point of view, the kit studied has good reliability, and could be used in the routine application for the control of illegal use of the drug.

Determination and characterization of vitamin B12 in the muscles and head innards of edible shrimp

We determined the vitamin B12 content in both the muscles and head innards of various shrimp species [Argis lar (Owen, 1839); Togezako shrimp, Argis toyamaensis (Yokoya, 1933); Pandalopsis japonica, Balss, 1914; Pandalus eous Makarov, 1935] using a microbiological assay based on Lactobacillus delbrueckii subsp. lactis ATCC7830. Approximately 2–4 µg vitamin B12/100 g wet weight—a considerable amount—was detected in shrimp muscles. The shrimp head innards contained significantly higher levels of vitamin B12 (~ 12–33 µg/100 g wet weight). Commercially available shrimp-innard products contained ~ 30 µg vitamin B12/100 g wet weight. We purified vitamin B12 compounds from the extracts of shrimp muscles and head innards using an immunoaffinity column. The muscle extract contained only one corrinoid compound, which was identified as vitamin B12 using liquid chromatography–electrospray ionization/tandem mass spectrometry, whereas the shrimp head innards contained three corrinoid compounds, which included large amounts of vitamin B12 and two smaller amounts of vitamin B12-d-monocarboxylic acid and tentatively identified vitamin B12 dicarboxylic acids.

Cryoprotective characteristics of different sugar alcohols on peeled Pacific white shrimp (Litopenaeus vannamei) during frozen storage and their possible mechanisms of action

ABSTRACT Sugar alcohols, also known as polyols, have been widely applied in food products for their unique properties. In this work, the effect of soaking treatments composed of the sugar alcohols xylitol, sorbitol, erythritol, lactitol, mannitol, maltitol, and isomaltitol on the quality properties of peeled Pacific white shrimp during frozen storage were evaluated. Samples treated with water and sodium pyrophosphate (Na4P2O7) were designated as the negative and positive controls, respectively. The results indicated that significant improvements were found in thawing, pressing, and cooking loss, myofibrillar protein content, myofibrillar Ca2+-ATPase activity, and textural variables in xylitol- and mannitol-treated shrimp as compared to that of control samples. Water mobility analyses showed that xylitol and mannitol effectively increased the relaxation times T 21 and T 22 and the percentage of A 21 (trapped water) but decreased the percentage of A 22 (free water) in muscle tissue. Additionally, the microstructural results indicated that soaking in xylitol and mannitol significantly slowed the damage caused to muscle tissues by large ice crystals. Here, the incorporated xylitol and mannitol molecules presumably replaced water molecules by forming large hydrogen bonds with the muscle proteins, thereby stabilizing their structures in the absence of water while in the frozen state and suppressing the destruction of tissue structure. To note, the lactitol, isomaltitol, and maltitol used in this study did not seem to significantly contribute to cryoprotective effects on shrimp muscle during the experimental period.

Antioxidant, antihemolysis, and retinoprotective potentials of bioactive lipidic compounds from wild shrimp (Litopenaeus stylirostris) muscle

ABSTRACT The oxidative stress damage on cells is an example of roles in the pathogenesis of different degenerative diseases and the search of compounds that can slow this oxidation is continuous. The aim of this work was to obtain bioactive fractions from wild shrimp (Litopenaeus stylirostris) muscle, in order to evaluate their protective capacity and chemo-structurally characterize them. ABTS and DPPH, and FRAP assays suggested that bioactive fractions possess free radical-scavenging capacity, and reducing power, respectively. An inhibitory effect observed on AAPH-induced hemolysis and results from an H2O2-derived radicals-scavenging assay (retinoprotective) suggest that these fractions can exert their protective activity in human cells. UV–Vis, fluorescence, 13C-, 1H-NMR, and ESI-MS studies performed on the most bioactive fraction, suggests that their main components are eicosapentaenoic acid, dioctyl phthalate, and a possibly novel indolocarbazole alkaloid derivative. These results suggest that these compounds are good candidates to further investigations as possible chemoprotective agents.

Effects of fish meal replacement by meat and bone meal supplemented with garlic (Allium sativum) powder on biological indices, feeding, muscle composition, fatty acid and amino acid profiles of whiteleg shrimp (Litopenaeus vannamei)

Shortage of fish meal (FM) resources in the marine environment, high price and high demand for this ingredient led researchers to seek for alternative protein resources such as meat and bone meal (MBM). The effects of adding MBM and garlic powder to the shrimp diet on growth performance, muscle composition, amino acid and fatty acid profiles of whiteleg shrimp (5.00 ± 0.23 g) were investigated. A total of six dietary treatments were formulated: 0%MBM (control without garlic powder), 25%MBM and 50%MBM (treatments without garlic powder; WG treatments); 0%MBM+G (control with garlic powder), 25%MBM+G and 50%MBM+G (treatments with garlic powder; G treatments). Our results indicated that increase MBM level in the diets (up to 50%MBM) impaired growth performance, muscle composition, fatty acid and amino acid profiles in the muscle of shrimp. Interestingly, garlic supplementation improved the aforementioned factors so that shrimp fed 50%MBM+G diet had no significant difference when compared to 0%MBM group. The current results indicated that garlic could increase levels of FM replacement by increasing feed intake, improving protein and amino acid utilization. Overall, 50%MBM+G diet is recommended for use in shrimp production.

Effect of varying levels of dietary protein on the growth performances of Indian white shrimp Penaeus indicus (H. Milne Edwards)

A 120 days grow out culture trial of Indian white shrimp, Penaeus indicus was carried out to ascertain the effect of different dietary level of protein in pond system. Three experimental feeds with crude protein (CP) - 30 (P30), 35 (P35) and 40% (P40) levels and their effects on growth performance of shrimps were studied for a period of 120 days. Shrimps fed with P30 and P35 recorded significantly higher average body weight, 14.29 ± 0.06 g and 14.24 ± 0.19 g respectively compared to the group fed with higher protein feed, P40 (13.13 ± 0.16 g). There was no significant difference (p < .05) in proximate composition of shrimp muscle fed with different feeds. The feed conversion ratio (FCR) was significantly higher in P40 (2.38 ± 0.61) while it was comparable between P30 and P35 (2.10 ± 0.01 and 2.11 ± 0.28 respectively). The protein efficiency ratio (PER) was significantly different among the treatments (1.58 ± 0.05, 1.33 ± 0.02 and 1.03 ± 0.03 in P30, P35 and P40 respectively). Productivity (kg/ha) was also significantly lower (P > .05) in P40 (2519.85 ± 18.02) while it was comparable between P30 (2930.17 ± 114.20) and P35 (3007.01 ± 153.02). The present study revealed that a protein level of 30–35% in practical diet is optimal for grow out pond culture of Indian white shrimp, P.indicus.

Effect of pulsed electric field treatments on melanosis and quality changes of Pacific white shrimp during refrigerated storage

Polyphenoloxidase (PPO) from Pacific white shrimp was subjected to Pulsed electric field (PEF) at varying specific energy (54-483 kJ/kg) and pulse number (200-600). PPO activity was decreased as both parameters increased (P < 0.05). Among shrimp treated with PEF, those subjected to PEF-T3 (483 kJ/kg, 600 pulses) had the lower melanosis score than other PEF treatments and the control, packaged in polystyrene trays and wrapped with shrink film, during 10 days of storage at 4 °C (P < 0.05). Highest shear force values were noticed with PEF-T3 treated sample at the end of storage period (day 10) (P < 0.05). Microstructural gaping between shrimp muscle fibers was notably higher in PEF-T3. No protein degradation was observed for all samples, regardless of PEF treatments. Lower mesophilic and psychrophilic microbial counts in shrimp were obtained when PEF-T3 was implemented. After 10 days of storage, higher sensory scores of PEF-T3 treated samples were also attained, as compared to others (P < 0.05). Quality deterioration of shrimp was retarded with the aid of PEF.

Elimination of the major allergen tropomyosin from shrimp muscle by boiling treatment

Tropomyosin (TM) is the major allergen found in invertebrates, including shrimp. To reduce the allergenicity of shrimp muscle, attempts were made to eliminate TM from the muscle by boiling. By boiling cubes (~ 1 g) of shelled shrimp muscle in 10 volumes of water (w/v) for 20 min, 7.1% of TM remained as determined by SDS-PAGE. Increasing the boiling water up to 2000 volumes of water did not result in improved elimination. When the muscle cubes were treated at 121 °C for 20 min in 2000 volumes of water, enzyme-linked immunosorbent assay (ELISA) reactivity against TM was reduced to 2.0 × 10−2 fold. After successive second and third treatments under the same conditions, ELISA reactivity was reduced to 4.2 × 10−5 and 1.6 × 10−5 folds, respectively. In addition, TM content in the muscle after the third treatment was lower than the threshold value for mandatory labeling (10 μg of ingredient proteins per 1 g of food). Thus, boiling treatment, especially high-pressure heating, can be an effective method for providing hypoallergenic shrimp for those who are allergic to shrimp and related invertebrates.

Evaluation of metal pollution-induced biological effects in Chinese shrimp Fenneropenaeus chinensis by NMR-based metabolomics

Metal pollution in Laizhou Bay along the Bohai Sea in China has been posing a risk on fishery species and hence may affect seafood quality. In this work, shrimps Fenneropenaeus chinensis were sampled from three sites, namely, a reference (site 6334) and two metal-polluted (sites 6262 and 7262) sites, located in Laizhou Bay. The metal concentrations in shrimp muscle tissues were tested using the ICP-MS technique. The Cr and Cu concentrations were the highest in the shrimp samples from site 7262, exceeding the national seafood safety standard Ⅱ, and the As concentration was much higher than the national seafood safety standard Ⅲ. NMR-based metabolomics indicated that metal pollution induced oxidative and immune stresses, damaged the muscular structure, and disrupted energy metabolism in shrimps at sites 6262 and 7262, in particular disturbed osmotic regulation in shrimps at site 7262. Glycine and serine could serve as biomarkers for Cd in F. chinensis.

Effects of T-2 toxin on the muscle proteins of shrimp (Litopenaeus vannamei)-a proteomics study.

T-2 toxin (T-2) is a potent mycotoxin and a common contaminant of aquatic animal feed, posing a serious risk to health and aquatic animals. We investigated the effect of T-2 on shrimp muscle proteins using proteomics and conventional biochemical methods. Shrimp were fed a diet containing T-2 at 0-12.2mg kg-1 for 20 days, and changes to the muscle protein composition, ATPase activities, and the sulfhydryl (SH) content and hydrophobicity of actomyosin (AM) were determined. A proteomics study of the proteins was conducted with sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), two-dimensional (2D) electrophoresis, and matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF/TOF MS). Exposure to T-2 markedly affected the muscle protein composition of shrimp in a concentration-responsive manner that displayed a diphasic effect. At a low T-2 concentration (1.2mg kg-1 ), the levels of three major muscle proteins (myofibrillar, sarcoplasmic, and stroma) increased but at higher concentrations they declined progressively. T-2 exposure also led to a breakdown of muscle proteins as evidenced by increases in alkali-soluble protein and the surface hydrophobicity (SoANS) of AM. Thirty differentially expressed proteins were detected, 12 of which showed a concentration-response relationship with T-2 exposure. Among them, 11 homologous proteins were identified by mass spectrometry (MS), with several being key enzymes in energy metabolism. This study demonstrated that T-2 exposure at medium to high concentrations could significantly affect the protein composition and quality of shrimp muscle, and potentially some of its key metabolisms. One of the arginine kinases (spot 27) was particularly responsive to T-2 and could potentially be used as a biomarker protein for T-2 intoxication by shrimp. © 2019 Society of Chemical Industry.

δ15N as an indicator of freshwater systems suitable for edible fish production

• δ 15 N of San Roque Lake samples denotes a high influence of sewage discharge. • San Roque Lake apparently is not a safe source for edible fish production. • The δ 15 N fish value can be used as biomarker for anthropogenic pollution. Anthropogenic inputs are affecting freshwaters. Stable isotope ratios of nitrogen (δ 15 N) are useful to track anthropogenic pollution in food webs across different habitats, species and trophic levels. Córdoba province (Argentina) has serious problems of eutrophication and pollution in some of its freshwater reservoirs. To evaluate the different anthropogenic inputs in the three most important reservoirs in Córdoba: San Roque Lake (SRL), Los Molinos Lake (LML) and Río Tercero Reservoir (RTR), δ 15 N was measured in water, plankton, shrimp ( Palaemonetes argentinus ) and fish ( Odontesthes bonariensis ) muscle samples. Results show that δ 15 N values of SRL samples (δ 15 N values between 14.9 and 20.0‰) are higher than those of the analogous samples from the other reservoirs, and denote a high influence of sewage discharge in this lake. The results show that the sewage isotopic signals in water were transferred to primary producers, then to mobile consumers, including fish. The findings of this study suggest that this reservoir is a source apparently not safe for food production, like edible fish. Finally, biota has proven to be a sensitive organism whose δ 15 N value can be used as bioindicator for pollution and human impact on the ecosystem in which it lives.

Growth and Lipidomic Responses of Juvenile Pacific White Shrimp Litopenaeus vannamei to Low Salinity.

The Pacific white shrimp (Litopenaeus vannamei), a euryhaline penaeid species, can tolerate a wide range of salinities, but little is known on its strategies to cope with low salinity fluctuations from the aspect of lipidomics. Thus, in this study, L. vannamei were grown in two different salinities [3 and 30‰ (control)] for 8 weeks, and then an liquid chromatography (LC)–mass spectrometry (MS)-based lipidomics analysis was performed to reveal the lipid profile differences in gill and muscle. L. vannamei under low salinity had lower weight gain and condition factor than the control shrimp at 30‰, but no differences were found in survival and hepatopancreas index. A higher number of differential lipid metabolites were identified in gill than in muscle in L. vannamei at salinity 3‰ relative to the control shrimp at salinity of 30‰ (159 versus 37), which belonged to 11 and 6 lipids classes, respectively. Of these lipids, phosphatidylcholine (PC), phosphatidylinositol (PI), phosphatidic acid (PA), phosphatidylethanolamine (PE), and triglyceride (TG) were the main lipids in both shrimp gill and muscle, regardless of salinities. Compared with the control shrimp at salinity 30‰, the percentage of PC significantly reduced, but TG and PA significantly increased in gill of shrimp at salinity 3‰. Moreover, the relative fatty acid abundances showed significant changes in L. vannamei between the two salinity groups, but the patterns of the changes were complex and were fatty acid dependent. Neither lipid nor fatty acid composition in muscle was affected by salinity. Further pathway analysis showed that these metabolites were closely related to lipid and fatty acid metabolic pathways. All the findings in this study reveal that the lipid variations are closely related to bio-membrane structure, mitochondrial function, energy supply, or organic osmolyte contents in hemolymph for improving osmoregulatory capacity of L. vannamei under low salinity.

Pharmacokinetics of oxytetracycline in Pacific white shrimp, Penaeus vannamei, after oral administration of a single-dose and multiple-doses

The present study was designed to explore the pharmacokinetics and tissue levels of oxytetracycline in the Pacific white shrimp (Penaeus vannamei) after oral administration of a single-dose (100 mg/kg) and multiple doses (100 mg/kg, six times). Oxytetracycline concentrations in the hemolymph, hepatopancreas, and muscle of Pacific white shrimp were determined using high-performance liquid chromatography. Pharmacokinetic parameters were analyzed based on the statistical moment theory. The results showed faster absorption of oxytetracycline in hepatopancreas (Tmax = 1 h) than in the hemolymph (Tmax = 6 h) and muscles (Tmax = 6 h) after single-dose oral administration. Meanwhile, the oxytetracycline peak concentration in the hepatopancreas was the highest (> 140 μg/g), followed by the concentration in the hemolymph (> 25 μg/mL), with the lowest concentration in the muscle (< 0.8 μg/g) in the single-dose group. Tissue distribution (area under the curve (AUC)0-∞) followed the order hepatopancreas > hemolymph > muscle, indicating that the hepatopancreas is the main organ involved in oxytetracycline metabolism in Pacific white shrimp. The t1/2z value of oxytetracycline in the hemolymph, hepatopancreas, and muscle were 11.01 h, 14.90 h and 23.53 h, respectively, indicating that oxytetracycline elimination in the muscle was the slowest among the tissues. In multiple-dose oral administration, some accumulation of oxytetracycline occurred in the hemolymph and muscle, while in the hepatopancreas, oxytetracycline reached a steady state following multiple-dose administration. The t1/2z values of oxytetracycline in the tissues were 20.52 h, 18.89 h, and 35.39 h, respectively, indicating that oxytetracycline elimination after multiple-dose administration in different tissues was slower than that after a single dose. In addition, the AUCss, Ctrough, and Cav values of oxytetracycline were graded as hepatopancreas > hemolymph > muscle, showing that the hepatopancreas also plays an important role in drug metabolism and elimination after multiple-dose oral administration.

Sodium erythorbate, stable chlorine dioxide, and gellan gum glazing for shelf life extension of commercial peeled shrimp ( Litopenaeus vannamei ) during frozen storage

The combined effect of sodium erythorbate, stable chlorine dioxide, and gellan gum glazing on quality of peeled shrimp was investigated during frozen storage, and compared with traditional water-ice-glazing treatment. Data revealed that the growth of total aerobes, Escherichia coli, and Staphylococcus aureus was significantly inhibited in the combined treatment, compared to the water-ice-glazing group. Examination of tissue texture and microstructure verified that the combined glazing effectively maintained springiness and chewiness of the shrimp muscle, and this treatment showed a positive effect on stability and integrity of tissue microstructures. Myofibrillar protein content and Ca2+-ATPase activity in muscle treated with combination were significantly higher than the water-ice-glazing treatment. SDS-PAGE results confirmed that this treatment markedly slowed the degradation of muscle proteins. Additionally, the combined treatment significantly decreased the amount of protein carbonyls and dityrosine, which was mainly governed by the anti-oxidization effect of incorporated sodium erythorbate. Practical applications Ice-glazing is a surface coating process and is especially useful in the field of shrimp preservation, which prevents incidence of surface drying and dehydration, freezer burn, oxidation, and/or rancidity. However, the traditional water-ice-glazing can lead to cracking and sublimation during long period of frozen storage. The bacterial contamination cannot be completely suppressed or inactivated by the single ice-glazing treatment. Among glazing processes, chitosan-based glazings have been most widely studied to maintain quality of shrimp products. However, chitosan is water-insoluble, relatively expensive, and highly viscous, which greatly limits its practical applications. For these reasons, alternative treatments that can form a stable and uniform glaze on surface of shrimp should be considered to minimize bacterial contamination and inhibit quality deterioration of frozen products. Outcome of the current study provides information regarding an optimum glazing formulation for shelf-life extension of shrimp during frozen storage.