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Abstract Background Autophagy is a conserved catabolic process in eukaryotes that contributes to cell survival in response to multiple stresses and is important for organism fitness. Extensive research has shown that autophagy plays a pivotal role in both viral infection and replication processes. Despite the increasing research dedicated to autophagy, investigations into shrimp autophagy are relatively scarce. Results Based on three different methods, a total of 20 members of the ATGs were identified from F. chinensis, all of which contained an autophagy domain. These genes were divided into 18 subfamilies based on their different C-terminal domains, and were found to be located on 16 chromosomes. Quantitative real-time PCR (qRT-PCR) results showed that ATG genes were extensively distributed in all the tested tissues, with the highest expression levels were detected in muscle and eyestalk. To clarify the comprehensive roles of ATG genes upon biotic and abiotic stresses, we examined their expression patterns. The expression levels of multiple ATGs showed an initial increase followed by a decrease, with the highest expression levels observed at 6 h and/or 24 h after WSSV injection. The expression levels of three genes (ATG1, ATG3, and ATG4B) gradually increased until 60 h after injection. Under low-salt conditions, 12 ATG genes were significantly induced, and their transcription abundance peaked at 96 h after treatment. Conclusions These results suggested that ATG genes may have significant roles in responding to various environmental stressors. Overall, this study provides a thorough characterization and expression analysis of ATG genes in F. chinensis, laying a strong foundation for further functional studies and promising potential in innate immunity.

Simple Summary: High carbonate alkalinity and high pH are the main characteristics of saline–alkaline water environments. This study aimed to elucidate the physiological mechanism of the hepatopancreas of Fenneropenaeus chinensis in response to saline–alkaline stress. Proteomics and metabolomics of hepatopancreas were employed to analyze the effects of high carbonate alkalinity (CA) stress and combined high carbonate alkalinity and high pH (CP) stress on shrimps after 24 h. The results indicated that several key proteins and metabolites involved in carbohydrate metabolism and fatty acid oxidation were significantly upregulated. Additionally, the antioxidant and immune systems were found to have been affected. These findings suggest that CA and CP stressors induced oxidative stress in the hepatopancreas of F. chinensis, resulting in impaired immunity and diminished inflammatory responses. F. chinensis may resist osmotic pressure imbalances caused by CA or CP stress by upregulating the energy metabolism level in the hepatopancreas. Our findings may offer valuable insights for further investigations into the saline–alkaline water culture of F. chinensis. The rapid development of the mariculture industry has been hindered by limited coastal aquaculture space. To utilize the abundant inland saline–alkaline water, we studied the physiological effects of high carbonate alkalinity stress and high pH stress on Fenneropenaeus chinensis. The study employed quantitative proteomics by tandem mass tag (TMT) and non-targeted metabolomics analysis using a liquid chromatograph mass spectrometer (LC-MS) to understand the physiological and biochemical adaptive mechanisms of the hepatopancreas of F. chinensis in response to saline–alkaline stress at the molecular level. We designed two stress groups as follows: a high carbonate alkalinity (CA) group and a combined high carbonate alkalinity and high pH (CP) group. The study found that the protein and metabolic profiles of the two stress groups were changed, and the CP group, which was exposed to dual stresses, incurred more severe damage to the hepatopancreas compared to that of the CA group. After exposure to CA and CP, the hepatopancreas of F. chinensis showed significant alterations in 455 proteins and 50 metabolites, and 1988 proteins and 272 metabolites, respectively. In addition, F. chinensis upregulated the level of energy metabolism in the hepatopancreas to defend against osmotic imbalance caused by CA or CP stress, which was demonstrated by the significant upregulation of important proteins and metabolites in glycolysis, pyruvate metabolism, TCA cycle, and fatty acid oxidation. Additionally, pattern recognition receptors, the phenol oxidase system, and various immune-related metabolic enzymes and metabolites were also affected. The immune homeostasis of F. chinensis was affected by the alteration of the antioxidant system following exposure to CA or CP. These findings provide valuable information for F. chinensis saline–alkaline water cultivation practices. [ABSTRACT FROM AUTHOR]

Background: Autophagy is a conserved catabolic process in eukaryotes that contributes to cell survival in response to multiple stresses and is important for organism fitness. Extensive research has shown that autophagy plays a pivotal role in both viral infection and replication processes. Despite the increasing research dedicated to autophagy, investigations into shrimp autophagy are relatively scarce. Results: Based on three different methods, a total of 20 members of the ATGs were identified from F. chinensis, all of which contained an autophagy domain. These genes were divided into 18 subfamilies based on their different C-terminal domains, and were found to be located on 16 chromosomes. Quantitative real-time PCR (qRT-PCR) results showed that ATG genes were extensively distributed in all the tested tissues, with the highest expression levels were detected in muscle and eyestalk. To clarify the comprehensive roles of ATG genes upon biotic and abiotic stresses, we examined their expression patterns. The expression levels of multiple ATGs showed an initial increase followed by a decrease, with the highest expression levels observed at 6 h and/or 24 h after WSSV injection. The expression levels of three genes (ATG1, ATG3, and ATG4B) gradually increased until 60 h after injection. Under low-salt conditions, 12 ATG genes were significantly induced, and their transcription abundance peaked at 96 h after treatment. Conclusions: These results suggested that ATG genes may have significant roles in responding to various environmental stressors. Overall, this study provides a thorough characterization and expression analysis of ATG genes in F. chinensis, laying a strong foundation for further functional studies and promising potential in innate immunity. [ABSTRACT FROM AUTHOR]

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Simple Summary: In this research, we established inbred families of Fenneropenaeus chinensis with an inbreeding coefficient of 0.25, and studied how inbreeding depression affects the larval development. We examined gene frequency changes in two developmental stages through sequencing. The results showed significant inbreeding depression in larval survival rates during hatching and two major developmental stages, ranging from 24.36% to 45.28%. Sequencing at these stages revealed deviations from Mendelian segregation, with homozygote deficiency and heterozygote excess being the primary selection types. The elimination during the larval stage resulted in more heterozygotes being retained and increased the population's heterozygosity. These findings indicate the presence of large amount of harmful recessive alleles in the Chinese shrimp genome and their potential criteria for elimination. The study provide valuable insights into the mechanisms of inbreeding depression in marine animals and provides guidance for shrimp population breeding strategies. Marine animals possess genomes of considerable complexity and heterozygosity. Their unique reproductive system, characterized by high fecundity and substantial early mortality rates, increases the risk of inbreeding, potentially leading to severe inbreeding depression during various larval developmental stages. In this study, we established a set of inbred families of Fenneropenaeus chinensis, with an inbreeding coefficient of 0.25, and investigated elimination patterns and the manifestations of inbreeding depression during major larval developmental stages. Reduced-representation genome sequencing was utilized to explore the genotype frequency characteristics across two typical elimination stages. The results revealed notable mortality in hatching and metamorphosis into mysis and post-larvae stages. Inbreeding depression was also evident during these developmental stages, with depression rates of 24.36%, 29.23%, and 45.28%. Segregation analysis of SNPs indicated an important role of gametic selection before hatching, accounting for 45.95% of deviation in the zoea stage. During the zygotic selection phase of larval development, homozygote deficiency and heterozygote excess were the main selection types. Summation of the two types explained 82.31% and 89.91% of zygotic selection in the mysis and post-larvae stage, respectively. The overall distortion ratio decreased from 22.37% to 12.86% in the late developmental stage. A total of 783 loci were identified through selective sweep analysis. We also found the types of distortion at the same locus could change after the post-larvae stage. The predominant shifts included a transition of gametic selection toward normal segregation and other forms of distortion to heterozygous excess. This may be attributed to high-intensity selection on deleterious alleles and genetic hitchhiking effects. Following larval elimination, a greater proportion of heterozygous individuals were preserved. We detected an increase in genetic diversity parameters such as expected heterozygosity, observed heterozygosity, and polymorphic information content in the post-larvae stage. These findings suggest the presence of numerous recessive deleterious alleles and their linkage and suggest a major role of the partial dominance hypothesis. The results provide valuable insights into the mechanisms of inbreeding depression in marine animals and offer guidance for formulating breeding strategies in shrimp populations. [ABSTRACT FROM AUTHOR]

The resource of Fenneropenaeus chinensis has declined sharply due to excessive fishing intensity, ecological changes and diseases. In order to supplement the fishing yield and restore resources of F. chinensis, the relevant authorities have carried out the activities of stock enhancement and releasing. It can increase biomass and recover resources. However, compared with increasing biomass, there were still few reports on its effect on the recovery of resources. Resource recovery is a process related to whether the released individuals can form a reproductive population. Up to now, there has been a lack of evidence whether the released F. chinensis can complete the entire life history, and form reproduction population. In this study, gravid female shrimp after spawning migration were captured from coastal waters of Haiyang, Qingdao, and Yellow Sea. After identifying parentage relationships using simple sequence repeat (SSR) and mtDNA haplotype, it was finally confirmed that there were eight released individuals in the recapture samples. It was confirmed for the first time that at least part of the released F. chinensis can complete overwintering and reproductive migration, and maintain the migration habits as their wild counterparts. Therefore, we infered that the released shrimp can reproduce under natural conditions, these F. chinensis can form reproductive populations theoretically if without human intervention. These results indicated that enhancenment and release activities have a positive effect on resource recovery. [ABSTRACT FROM AUTHOR]

Marine stock enhancement is not only commonly reported to amplify the target species production but also induces some potential threats or effects at multiple ecological levels in the receiving ecosystem. Studies on the interaction between released and naturally occurring organisms are necessary to avoid or minimize the adverse impacts of invasive species from stock enhancement in the receiving system. Chinese shrimp Fenneropenaeus chinensis, are an important stock enhancement species, and in recent years approximately 10 billion have been released annually into the coastal waters of China. Owing to fishing pressure and the ecological complexity of the open sea, the interaction between the released shrimp and native species may be weak and undetectable. Studies on the ecological impacts of such intensive releasing activities are limited. Therefore, in this study, an in-situ mesocosm experiment was carried out to determine if the released shrimp altered the relative composition and niche characteristics of fish, the results of which could serve as a reference to the local risk management of the species stock enhancement. The mesocosm was located in the shrimp-releasing channel of Weihe, Laizhou Bay, from April to September 2019. A cross design of four treatments with three replicates was conducted in the mesocosm. The habitats were homogenized across the replicates by mixing substrates and filtering seawater with a 0.28 cm sieve. The number of individual shrimp larvae released into net enclosures in each of the four treatments were: A) 2 400, B) 1 800, C) 1 200, and O) 0. The treatments were designed to represent the release of 1 billion, 750 million, 500 million, and no shrimp larvae (none-releasing) in the coastal waters of Laizhou Bay, respectively. The released shrimp larvae had an average body length of (1.63±0.18) cm and an average body width of (0.38±0.12) cm. At the end of the experimental period in September, shrimp and fishes were recaptured and their Levin's niche breadth and overlap indices were examined in each enclosure. Results indicated that within the enclosures of the four treatments, the recapture rates of shrimp ranged from 8.16% to 12.69% and had an average value of 9.87%. The number of recaptured shrimp increased with the number released, and had the highest value in enclosure A. However, the total biomass, average individual mass, and recapture rate of shrimp did not show a similar pattern among enclosures. The recapture rate of shrimp was significantly different among the treatments and had the highest value in enclosure C. The fish species composition was similar across all four treatment enclosures and included six species with three different feeding habits: Omnivores (Konosirus punctatus and Liza haematocheila), zooplanktivores (Thryssa mystax and Sardinella zunasi), and fish/shrimp predators (carnivores) (Acanthogobius sp. and Sparus microcephalus czerskii). Of the fish species, Acanthogobius sp. dominated in all enclosures, while S. m. czerskii occurred in only a few. There was no significant difference in the number and biomass of total fishes and carnivorous fishes among enclosures. There were more omnivorous fishes in the released enclosures A–C, while the number of zooplanktivorous fishes decreased when shrimp were released and had the highest number and biomass in the non-released enclosure O. Moreover, fishes with different feeding habits had variable niche breadths among the four treatment enclosures. Most fish species had a wider niche breadth in enclosures with released shrimp (enclosure A–C) than in enclosure O. Both the fish´s niche overlap indices and the species pairs with high niche overlap (> 0.75) decreased in the order non-released enclosure O > released enclosure B > enclosure C > enclosure A. The carnivorous fish Acanthogobius sp. had more pairs with niche overlap indices (> 0.75) in the non-released enclosure O than in the other three treatments. A similarity analysis and multidimensional plot indicated that enclosures A and O could be differentiated by the relatively long similarity distance and little overlap area. The results of the experiment suggest that the shrimp recapture efficiency did not increase when shrimp were released. In the waters of the study area, released shrimp could have a positive effect on the total output of both shrimp and fish, especially for omnivorous and carnivorous fishes, as the shrimp could share predation pressure and provide food for them. In addition, the shrimp release may affect the relative composition and niche characteristics of fish by increasing their niche breadth and reducing the overlap between fishes with different feeding habits, and the impacts may be more detectable as the shrimp number increases.

The present study compared the structure of mixilliped of Fenneropenaeus chinensis between the larval and adult stage and investigated the effect of the structural difference on the immunity of F. chinensis. A fourteen day and a one-month long culture trial were conducted each with postlarvae and adults of F. chinensis in the biofloc, mixed water (50% biofloc:50% clear seawater) and seawater control. Immune-related genes mRNA expressions of postlarvae was analysed by quantitative reverse transcription polymerase chain reaction (qRT-PCR). And the analysis of adult stage immunity was carried out using phenoloxidase (PO) enzyme activation in haemocyte. In the postlarvae, the final body weights were 51.43 and 58.47 mg for the biofloc water and the control seawater, respectively. On the other hand, the final body weights of the adults were significantly different between biofloc water and seawater. The survival rate showed the opposite trend to the growth rate. Immune related genes mRNA expression levels in the postlarvae in the biofloc water were significantly lower than those in the seawater. While, the adult stage showed significantly higher PO enzyme activations in the biofloc water than in the seawater with the PO enzyme activation increasing proportionally to the biofloc concentration. This result is considerably explained by the observations of setal morphological structures of the third maxilliped: postlarvae have short serrulated setae that compose the small ‘net’ structure while adults had long and dense plumose setae. It is understood that the morphological difference of the maxilliped structure resulted in the different feeding abilities in the postlarvae and the adult F. chinensis to use bioflocs as food source.

Simple Summary: This study aimed to investigate the influencing mechanisms of the intestinal microbiota and gene expression of Fenneropenaeus chinensis under low-salinity stress. The 16S rDNA results suggest that the relative abundances of Photobacterium and Vibrio decreased significantly, whereas some bacteria, Shewanella, Pseudomonas, and Lactobacillus, became the predominant communities. Transcriptome sequencing identified numerous differentially expressed genes (DEGs) through various types of N-glycan biosynthesis, amino acid sugar and nucleotide sugar metabolism, and lysosomes to adapt to stress. Correlation analysis between microbiota and DEGs showed that significant changes in Pseudomonas, Ralstonia, Colwellia, and Cohaesibacter were positively correlated with immune-related genes such as peritrophin-1-like and mucin-2-like, and negatively correlated with caspase-1-like. Salinity is an important environmental stress factor in mariculture. Shrimp intestines harbor dense and diverse microbial communities that maintain host health and anti-pathogen capabilities under salinity stress. In this study, 16s amplicon and transcriptome sequencing were used to analyze the intestine of Fenneropenaeus chinensis under low-salinity stress (15 ppt). This study aimed to investigate the response mechanisms of the intestinal microbiota and gene expression to acute low-salinity stress. The intestinal tissues of F. chinensis were analyzed using 16S microbiota and transcriptome sequencing. The microbiota analysis demonstrated that the relative abundances of Photobacterium and Vibrio decreased significantly, whereas Shewanella, Pseudomonas, Lactobacillus, Ralstonia, Colwellia, Cohaesibacter, Fusibacter, and Lachnospiraceae_NK4A136_group became the predominant communities. Transcriptome sequencing identified numerous differentially expressed genes (DEGs). The DEGs were clustered into many Gene Ontology terms and further enriched in some immunity- or metabolism-related Kyoto Encyclopedia of Genes and Genomes pathways, including various types of N-glycan biosynthesis, amino acid sugar and nucleotide sugar metabolism, and lysosome and fatty acid metabolism. Correlation analysis between microbiota and DEGs showed that changes in Pseudomonas, Ralstonia, Colwellia, and Cohaesibacter were positively correlated with immune-related genes such as peritrophin-1-like and mucin-2-like, and negatively correlated with caspase-1-like genes. Low-salinity stress caused changes in intestinal microorganisms and their gene expression, with a close correlation between them. [ABSTRACT FROM AUTHOR]

Extensive applications of fishery stock enhancement worldwide bring up broad concerns about its negative effects, creating a pivotal need for science‐based assessment and planning of enhancement strategies. However, the lack of mechanistic understanding of enhanced population dynamics, particularly the density‐dependent processes, leads to compromise in model development and limits the capacity in predicting enhancement effects. Here, we developed an individual‐based model based on dynamic energy budget theory and full life‐history processes, to understand the mechanism of density dependence in population dynamics that emerge from individual‐level processes. We demonstrated the utility of the model framework by applying it to an extensively enhanced species, Chinese prawn (Fenneropenaeus chinensis, Penaeidae). The model could yield projections reflecting the observed trajectory of population biomass and yields. The model also delineated the key effects of density dependence on the vital rates of growth, fecundity and starvation mortality. Regarding the manifold effects of stock enhancement, we demonstrated a dampened shape in population biomass and yields with increasing magnitude of enhancement, and trade‐offs between the ecological and economic objectives, that is, pursuing high benefit might compromise the wild population without proper management. Furthermore, we illustrated the possibility of combining stock enhancement and harvest regulation in promoting population recovery while maintaining fisheries yields. We highlight the potential of the proposed model for understanding density dependence in enhancement programme, and for designing integrated management strategies. The approach developed herein may serve as a general approach to assess the population dynamics in stock enhancement and inform enhancement management. [ABSTRACT FROM AUTHOR]

Glutathione S-transferases (GSTs) are a superfamily of multifunction enzymes involved in the regulation of redox homeostasis and innate immune responses against various pathogenic infections in marine invertebrates. In the present study, a delta class GST gene (designated as FcδGST) was cloned from Fenneropenaeus chinensis using rapid amplification of cDNA ends (RACE) technology. The complete cDNA sequence of FcδGST was 780 bp in length, which includes a 27-bp 5′ non-coding region (UTR), a 117-bp 3′ UTR, a 636-bp open reading frame (ORF), and a polyadenylate signal site (AATAAA) presented at the upstream of poly A tail. The FcδGST gene encoded 211 amino acids peptide, including a GST_N domain and a GST_C domain, and exhibited high similarity with previously reported delta GSTs. The predicted molecular mass of FcδGST protein was 23.39 kDa, and its theoretical isoelectric point (pI) was 5.34. The FcδGST mRNA transcripts were ubiquitously expressed in all the tested tissues, with the highest expression level in hemocytes and hepatopancreas. During the stimulation of Vibrio anguillarum or white spot syndrome virus (WSSV), the mRNA expression of FcδGST in hemocytes and hepatopancreas revealed significant up-regulation. The purified recombinant FcδGST protein (designated as rFcδGST) exhibited specific catalytic activity against 1-chloro-2, 4-dinitrobenzene (CDNB) substrate with relatively low stable enzymatic activities. These results indicated that FcδGST was a fragile but typical novel delta class GST member and potentially involved in the innate immune responses of F. chinensis. [ABSTRACT FROM AUTHOR]

Fenneropenaeus chinensis is an important fishery species in China. Hatchery-reared seeds have been released into the wild for improvement of shrimp productivity. Jinzhou bay is the major natural habitat and we used this location to temporally monitor the genetic effects of release of hatchery stocks on local F. chinensis populations across five years. A set of 13 microsatellite markers were used to evaluate genetic patterns across 2015, 2016 and 2019. We observed a significant Hardy-Weinberg disequilibrium across all stocks. The inbreeding coefficient (Fis) was positive (0.121-0.131) for all stocks. A loss of genetic diversity was detected in the 2019 stock and significant differences were observed for number of different alleles, number of effective alleles, allelic richness and unbiased expected heterozygosity in the 2019 stock (P < 0.05). The highest pairwise relatedness and the lowest observed heterozygosity were also observed in 2019 stock. Moreover, a small but significant genetic differentiation was detected between the 2019 stock and the stocks of the previous two years. Given the continuously large scale of artificial enhancements in this area, these data may indicate that releases of hatchery-reared F. chinensis individuals may be associated with inbreeding and potentially the reduction in genetic diversity of the F. chinensis population. [ABSTRACT FROM AUTHOR]

探究常压煎炸和真空煎炸对中国对虾理化性质和感官品质的影响。测定了不同煎炸温度下两种煎炸方式对中国对虾的水分含量、含油量、色泽、虾青素含量和感官品质的影响。结果表明：随着煎炸温度的升高，两种煎炸方式下中国对虾的水分含量均降低，含油量均增加，但真空煎炸下中国对虾的变化幅度较低；两种煎炸方式下中国对虾的虾青素含量均随着煎炸温度的升高呈现先增加后减少的趋势；相同热驱动力下，真空煎炸的中国对虾的色泽、虾青素含量和感官品质均优于常压煎炸的。相比于常压煎炸，真空煎炸的中国对虾品质更佳。 The effects of atmospheric frying and vacuum frying on physicochemical properties and sensory quality of Fenneropenaeus chinensis were studied. The influences of moisture content, oil content, color, astaxanthin content and sensory quality of fried Fenneropenaeus chinensis prepared by different frying methods under different frying temperatures were measured. The results showed that with the increase of frying temperature, the moisture content in fried Fenneropenaeus chinensis decreased and oil content increased, but the variation range was lower for vacuum fried Fenneropenaeus chinensis. The astaxanthin contents in atmospheric fried and vacuum fried Fenneropenaeus chinensis increased first and then decreased with the frying temperature increasing.However, under the same thermal driving force, the color, astaxanthin content and sensory quality of vacuum fried Fenneropenaeus chinensis were better than those of atmospheric fried Fenneropenaeus chinensis. In conclusion, compared with atmospheric frying, the quality of fried Fenneropenaeus chinensis prepared by vacuum frying is better.

Global warming is a challenge to animal health because of the increased environmental temperature, with subsequent induction of immune suppression and increased susceptibility to disease during summer. The Toll-like receptor (TLR) family is an essential pattern recognition receptor (PRR) that initiates the innate immune response by sensing conserved molecular patterns of pathogens. However, research on the TLR gene family in decapod crustaceans has been conducted sporadically, without systematic naming, and the relationship between pathogen immunity adaptation and adaptive evolution of immune-related genes is unclear. In this study, various TLR gene sequences in decapod crustaceans were collected, and the unified name of Fenneropenaeus chinensis was confirmed using sequence alignment. Structural characteristics and evolutionary analyses of TLR genes in decapod crustaceans were performed, and ten FcTLR genes were identified in F. chinensis. Protein domain analysis revealed that FcTLR proteins contain 4–25 LRR domains used to recognize different pathogens. Selection pressure analysis revealed that TLR1 and TLR9 were subjected to positive selection pressure in decapod crustaceans, which may be related to their resistance to environmental changes. Furthermore, the expression of ten TLR genes was detected in F. chinensis following white spot syndrome virus (WSSV) infection. The results demonstrated that FcTLR1, FcTLR7, and FcTLR9 responded positively, which was also consistent with the results of the protein domain and selection pressure analyses. This study provides new insights into the immune response and adaptive evolution of TLRs in decapod crustaceans to prevent environmental damage, such as pathogens and high temperature.

The relationship between inbreeding and traits of disease resistance in shrimp has not been studied comprehensively. To explore the effect of inbreeding on white spot syndrome virus (WSSV) resistance in Fenneropenaeus chinensis, we established F. chinensis “Huanghai No. 5” populations with different inbreeding coefficients. We infected F. chinensis individuals with WSSV to compare WSSV-resistance between five inbred groups and a control group. Survival time, survival rate, distribution of deaths, and cumulative mortality rate were analyzed. A mixed linear model was established based on the acquired data. The viral load in muscle tissue of F. chinensis of 12 families from the five inbred groups and the control group was determined at different time points via real-time PCR. The average survival and longest survival time of the inbred groups were lower than those of the control group, and the coefficient of variation was universally greater than that of the control group. The least squares means of survival time of the five inbred groups (F0.1325, F0.25, F0.3125, F0.375, F0.5) were 118.96 115.14, 124.58, 123.97, and 101.34 h, respectively, which were 10.28%, 13.16%, 6.04%, 6.5%, and 23.57% lower than that of the control group. Further, when the inbreeding coefficient increased by 10%, WSSV infection survival time was changed by − 7.76%, − 5.26%, − 1.93%, − 1.73%, and − 4.71% for the five inbred groups, respectively. Thus, the results indicated that inbreeding enhanced the susceptibility of F. chinensis to WSSV infection, and the resistance of F. chinensis to WSSV declined as the inbreeding coefficient values increased, consequently, resulting in greater population dispersion, intensified differentiation, and instability of resistant phenotypes. In conclusion, we elucidated the effect of inbreeding on F. chinensis resistance to WSSV infection and established a theoretical basis to conduct further research in the future.

Understanding inbreeding depressions (IBDs), the effect on the phenotypic performance of inbreeding, is of major importance for evolution and conservation genetics. Inbreeding depressions in aquatic animals were well documented in a domestic or captive population, while there is less evidence of inbreeding depression in natural populations. Chinese shrimp, Fenneropenaeus chinensis, is an important species in both aquaculture and fishery activities in China. To investigate inbreeding depression in natural populations, four Fenneropenaeus chinensis natural populations (Huanghua, Qinhuangdao, Qingdao, and Haiyang) were collected from the Bohai and Yellow seas. Microsatellite markers were used to evaluate individual inbreeding coefficients (F) of all samples. Furthermore, the effects of inbreeding on growth traits were investigated. The results showed marker-based F was continuous and ranged from 0 to 0.585, with an average of 0.191 ± 0.127, and there was no significant difference among the average F of the four populations. Regression analysis using the four populations showed inbreeding had a very significant (p < 0.01) effect on body weight. When analyzing a single population, regression coefficients were also all negative and those in Huanghua and in Qingdao were significant at the level of p < 0.05 and < 0.01, respectively. Inbreeding depressions, expressed as the percent change in body weight per 10% increase in F, were 2.75% in Huanghua, 2.22% in Qingdao, and 3.69% in all samples. This study provided a piece of rare evidence of inbreeding depression in natural populations and also guidance toward the conservation of wild Fenneropenaeus chinensis resources.

Fenneropenaeus chinensis is an important economic species in the north of China, and plays an important role in both marine fishing and aquaculture. Long-term overfishing has led to the rapid decline of wild F. chinensis resources. The traditional trawl survey could not meet the demands of the F. chinensis resource survey. In this study, environmental DNA (eDNA) technology was used to evaluate the biomass of F. chinensis in the traditional Qinghai (Qingdao Haiyang) fishing ground in the southern sea area of the Shandong Peninsula, with the purpose of verifying whether eDNA technology can provide a new resource assessment method for fisheries resource species such as F. chinensis. The eDNA quantitative results of the Qingdao water samples ranged from 1972 copies/L to 6937 copies/L, with an average of 4366 ±1691 copies/L. Those in Haiyang water samples ranged from 4795 copies/L to 8715 copies/L, with an average of 6737 ± 1348 copies/L. The concentration of eDNA in shrimp culture ponds ranged from 1.14 × 106 copies/L to 7.61 × 106 copies/L, with an average of 3.33 × 106 ± 2.28 × 106 copies/L. The amount of eDNA released by each gram of F. chinensis per 24 h was about 2.91 × 106 copies. According to this calculation, it was estimated that the distribution of F. chinensis was about one shrimp in every 300 m2 sea area. Similarly, it is estimated that one shrimp is distributed every 240 m2 in the Haiyang sea area. The result of this study confirms the feasibility of using eDNA to evaluate the biomass of shrimps. [ABSTRACT FROM AUTHOR]

Based on lots of results, the QM protein was proposed to be a tumor suppressor, and facilitate in the innate immune responses, especially the prophenoloxidase (proPO) activation system. In the present study, a cDNA of 761 bp for the QM of Chinese shrimp, Fenneropenaeus chinensis (designated as FcQM) was cloned via rapid amplification of cDNA ends (RACE) technique. The complete cDNA sequence of FcQM contained an open reading frame (ORF) of 663 bp, 5' untranslated regions (UTR) of 42 bp and 3' UTR of 56 bp, which encoded a polypeptide of 155 amino acid residues. The analysis of the peptide sequence of FcQM revealed that FcQM sequence contained a Ribosomal_L16 domain, an SH3-binding motif, an N-acylation site, two putative antibiotic binding sites, two putative protein kinase C phosphorylation sites and two acylamidation sites, which shared over 80 % similarity with previously identified QM protein genes. Quantitative real-time PCR (qRT-PCR) results showed that the transcript of FcQM was extensively distributed in all the tested tissues and most highly expressed in hemocytes and hepatopancreas. After challenged with Vibrio anguillarum or white spot syndrome virus (WSSV), the FcQM transcripts were significantly increased (p < 0.05) both in hepatopancreas and hemocytes. Hence, the analysis of sequence and transcription suggested that FcQM might play crucial roles responses to bacterial and viral invasion in innate immunity of arthropods. This study is the first report of the QM protein gene from F. chinensis, which would enrich the understanding of the innate immune defense mechanism in shrimp.

Cyclophilin A (CypA), a key member of the immunophilin family, is the most abundantly expressed one among the 16 identified cyclophilins. Besides acting as an intracellular receptor for cyclosporine A, CypA plays a vital role in various pathological responses such as inflammation and microbial infections. In the present study, the full-length cDNA of Fenneropenaeus chinensis CypA (FcCypA) was cloned by RACE technique. The complete sequence of FcCypA cDNA contained a 5' untranslated region (UTR) of 33 bp, a 3’ UTR of 341 bp with a polyA tail, and an open reading frame (ORF) of 495 bp encoding a polypeptide of 164 amino acids with the predicted molecular weight of 17.70 kDa. The amino acid sequence of CypA has a typical peptidyl prolyl cis-trans isomerase family tag sequence (YKGSTFHRVIPNFMCQGG) as those of other species. The mRNA transcripts of FcCypA were constitutively expressed in all the tested tissues, including eyestalk, gill, gonad, heart, hemocytes, hepatopancreas, intestine, muscle, nerve and stomach, with the highest expression level in hepatopancreas. The mRNA expression profiles of FcCypA in hemocytes and hepatopancreas could be significantly induced by the stimulation of Vibrio anguillarum suspension and white spot syndrome virus (WSSV) stock, which verifies that CypA has an effect on viral and bacterial infection in shrimps. These results indicate that CypA may be involved in the innate immunity, biological immune response and physiological stress response of Chinese shrimps.

To evaluate the effect of high voltage pulsed electric field (PEF) treatment (10–20 kV/cm, 5–15 min) on the structural characteristics and sensitization of crude extracts of arginine kinase from Fenneropenaeus chinensis. By simulated in vitro gastric juice digestion (SGF), intestinal juice digestion (SIF) and enzyme-linked immunosorbent assay (ELISA), AK sensitization was reduced by 42.5% when treated for 10 min at an electric field intensity of 15 kV/cm. After PEF treatment, the α-helix content decreased, and the α-helix content gradually changed to β-sheet and β-turn. Compared to the untreated group, the surface hydrophobicity increased and the sulfhydryl content decreased. SEM and AFM analyses showed that the treated sample surface formed a dense porous structure and increased roughness. The protein content, dielectric properties, and amino acid content of sample also changed significantly with the changes in the treatment conditions. Non-thermal PEF has potential applications in the development of hypoallergenic foods. • PEF technology is efficient and small temperature difference. • The molecular weight of AK was not significantly different after PEF treatment. • PEF treatment increases the surface roughness of AK. • PEF treatment effectively reduces the allergenicity of arginine kinase. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Hydrobiology / Shuisheng Shengwu Xuebao is the property of Editorial Department of Journal of Hydrobiology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Protein phosphorylation and dephosphorylation are the most common and important regulatory mechanisms in signal transduction, which play a vital role in immune defense response. Our previous study has found the level of tyrosine phosphorylation was significantly changed in the hemocytes of Fenneropenaeus chinensis upon white spot syndrome virus (WSSV) infection. In order to explore the relationship between protein phosphorylation and WSSV infection, the quantitative phosphoproteomics was employed to identify differential phosphorylated proteins in hemocytes of F. chinensis before and after WSSV infection, and elucidate the role of key differential phosphorylated proteins in WSSV infection process. The results showed that a total of 147 differential phosphorylated proteins were identified in the hemocytes, including 64 phosphorylated proteins and 83 dephosphorylated proteins, which were mostly enriched in pyruvate metabolism, TCA cycle, glycolysis, and ribosomal biosynthesis. Functional analysis of differential phosphorylated proteins showed that they were involved in cell apoptosis, cell phagocytosis, cell metabolism and antiviral infection. A total of 236 differential phosphorylation sites were found, including 91 modified sites in the phosphorylation proteins and 145 modified sites in the dephosphorylation proteins. Motif analysis showed that these phosphorylation sites could activate mitogen-activated protein kinase, P70 S6 kinase and other kinases in hemocytes. Moveover, the phosphorylation levels of eukaryotic protein initiation factor 4E binding proteins and histone H3 were further determined by ELISA and Western blotting, which both exhibited a significant increase post WSSV infection and reach their peak levels at 6 and 12 h, respectively. Moreover, we found that lactate, a metabolite closely related to pyruvate metabolism, TCA cycle and glycolysis, was significantly increased in the hemocytes after WSSV infection. This study revealed the protein phosphorylation response in hemocytes of F. chinensis to WSSV infection, which help to clarify the response characteristics and virus resistance mechanism of hemocytes in F. chinensis , and also facilitate further understanding of the interaction between WSSV and shrimp hemocytes. • The phosphorylation response of hemocytes was determined at the early WSSV infection stage. • 147 differential phosphorylated proteins were identified in the WSSV-infected hemocytes. • Differential phosphoproteins were significantly enriched in energy metabolism. • The lactate concentration in hemocytes was significantly increased after WSSV infection. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) is one of the typical metal pollutants in the Bohai Sea. To evaluate the acute toxicological effects of Cd on marine crustaceans, juvenile Fenneropenaeus chinensis and Portunus trituberculatus were exposed to Cd at environmentally relevant concentrations (5 and 50 μg/L) for 96 h. Cd accumulation, antioxidants and metabolite profiles were characterized to elucidate the responses of juvenile crustaceans to Cd stress. Significant Cd accumulation was observed in both juvenile crustaceans in 50 μg/L Cd-treated group. Results showed that Cd exposure induced hormesis based on the alterations of GSH, SOD and CAT activities (i.e. increased levels in the low concentration of Cd treatment and recovered levels in the high concentration of Cd treatment) in juvenile P. trituberculatus. Similarly, the responses of GSH contents presented hormesis pattern in Cd-treated juvenile F. chinensis. Na+-K+-ATPase contents were significantly elevated in 50 μg/L Cd-treated group. In addition, untargeted NMR-based metabolomics indicated Cd caused the disturbance in osmotic regulation and energy consumption in both juvenile F. chinensis and P. trituberculatus via different pathways. The immunotoxicity and movement disorder were uniquely demonstrated in juvenile P. trituberculatus after Cd exposure.

White spot syndrome virus (WSSV) is one of the most lethal viruses in shrimp aquaculture. Compared with other shrimp species, the Chinese shrimp (Fenneropenaeus chinensis) is more susceptible to WSSV. The mortality of WSSV-infected F. chinensis can reach 100% within a week. No effective solution currently exists to solve the WSSV problem in F. chinensis aquaculture. After years of research, we found that individual F. chinensis from the same family can carry different viral load at the same time post-WSSV infection. To better understand the anti-WSSV mechanism of F. chinensis, we analysed the transcriptomic data from F. chinensis with high and low WSSV load at the same time post-WSSV infection and from healthy F. chinensis, in a WSSV-resistant group and a WSSV-susceptible group, respectively. We identified more differentially expressed genes in F. chinensis with high WSSV load than in those with low WSSV load at the same time post-WSSV infection. Many differentially expressed genes were enriched in Gene Ontology terms related to binding function and the extracellular matrix-receptor interaction pathway, which might play important roles in the anti-WSSV processes among F. chinensis.

Lower pH gives rise to a harmful stress to crustacean. Here, we analyzed the proteomic response of Fenneropenaeus chinensis from control pH (pH value 8.2) and low pH (pH value 6.5) - treated groups by employing absolute quantitation-based quantitative proteomic (iTRAQ) analysis. Among the identified proteins, a total of 76 proteins differed in their abundance levels, including 45 upregulated and 31 downregulated proteins. The up-regulation of proteins like citrate synthase, cytochrome c oxidase, V-type proton ATPase, glyceraldehyde-3-phosphate dehydrogenase and fructose 1,6-bisphosphate-aldolase as well as the enrichment of the DEPs in multiple metabolic processes and pathways illustrated that increased energy and substrates metabolism was essential for F. chinensis to counteract low pH stress. Ion transporting related proteins, such as Na+/K+/2Cl− cotransporter and calmodulin, participated in the homeostatic maintenance of pH in F. chinensis. There were significant downregulation expressions of lectin, lipopolysaccharide- and beta-1,3-glucan binding protein, chitinase, cathepsin L and beta-glucuronidase, which indicating the immune dysfunction of F. chinensis when exposure to low pH condition. These findings can extend our understanding on the defensive mechanisms of the low pH stress and accelerate the breeding process of low pH tolerance in F. chinensis. • iTRAQ proteomic analysis was used to screen key response proteins and pathways in response to low pH stress. • 45 differentially up-regulated proteins and 31 differentially downregulated proteins were identified. • Low pH stress induced the oxidative stress and mitochondrial dysfunction in Fenneropenaeus chinensis. • The enhanced energy and substrates requirement were essential for Fenneropenaeus chinensis to confront the low pH stress. [ABSTRACT FROM AUTHOR]

A high‐quality reference genome is necessary to determine the molecular mechanisms underlying important biological phenomena; therefore, in the present study, a chromosome‐level genome assembly of the Chinese shrimp Fenneropenaeus chinensis was performed. Muscle of a male shrimp was sequenced using PacBio platform, and assembled by Hi‐C technology. The assembled F. chinensis genome was 1.47 Gb with contig N50 of 472.84 Kb, including 57.73% repetitive sequences, and was anchored to 43 pseudochromosomes, with scaffold N50 of 36.87 Mb. In total, 25,026 protein‐coding genes were predicted. The genome size of F. chinensis showed significant contraction in comparison with that of other penaeid species, which is likely related to migration observed in this species. However, the F. chinensis genome included several expanded gene families related to cellular processes and metabolic processes, and the contracted gene families were associated with virus infection process. The findings signify the adaptation of F. chinensis to the selection pressure of migration and cold environment. Furthermore, the selection signature analysis identified genes associated with metabolism, phototransduction, and nervous system in cultured shrimps when compared with wild population, indicating targeted, artificial selection of growth, vision, and behavior during domestication. The construction of the genome of F. chinensis provided valuable information for the further genetic mechanism analysis of important biological processes, and will facilitate the research of genetic changes during evolution. [ABSTRACT FROM AUTHOR]

Based on lots of results, the QM protein was proposed to be a tumor suppressor, and facilitate in the innate immune responses, especially the prophenoloxidase (proPO) activation system. In the present study, a cDNA of 761 bp for the QM of Chinese shrimp, Fenneropenaeus chinensis (designated as FcQM) was cloned via rapid amplification of cDNA ends (RACE) technique. The complete cDNA sequence of FcQM contained an open reading frame (ORF) of 663 bp, 5' untranslated regions (UTR) of 42 bp and 3' UTR of 56 bp, which encoded a polypeptide of 155 amino acid residues. The analysis of the peptide sequence of FcQM revealed that FcQM sequence contained a Ribosomal_L16 domain, an SH3-binding motif, an N-acylation site, two putative antibiotic binding sites, two putative protein kinase C phosphorylation sites and two acylamidation sites, which shared over 80 % similarity with previously identified QM protein genes. Quantitative real-time PCR (qRT-PCR) results showed that the transcript of FcQM was extensively distributed in all the tested tissues and most highly expressed in hemocytes and hepatopancreas. After challenged with Vibrio anguillarum or white spot syndrome virus (WSSV), the FcQM transcripts were significantly increased (p < 0.05) both in hepatopancreas and hemocytes. Hence, the analysis of sequence and transcription suggested that FcQM might play crucial roles responses to bacterial and viral invasion in innate immunity of arthropods. This study is the first report of the QM protein gene from F. chinensis, which would enrich the understanding of the innate immune defense mechanism in shrimp. [ABSTRACT FROM AUTHOR]

Cyclophilin A (CypA), a key member of the immunophilin family, is the most abundantly expressed one among the 16 identified cyclophilins. Besides acting as an intracellular receptor for cyclosporine A, CypA plays a vital role in various pathological responses such as inflammation and microbial infections. In the present study, the full-length cDNA of Fenneropenaeus chinensis CypA (FcCypA) was cloned by RACE technique. The complete sequence of FcCypA cDNA contained a 5' untranslated region (UTR) of 33 bp, a 3' UTR of 341 bp with a polyA tail, and an open reading frame (ORF) of 495 bp encoding a polypeptide of 164 amino acids with the predicted molecular weight of 17.70 kDa. The amino acid sequence of CypA has a typical peptidyl prolyl cis-trans isomerase family tag sequence (YKGSTFHRVIPNFMCQGG) as those of other species. The mRNA transcripts of FcCypA were constitutively expressed in all the tested tissues, including eyestalk, gill, gonad, heart, hemocytes, hepatopancreas, intestine, muscle, nerve and stomach, with the highest expression level in hepatopancreas. The mRNA expression profiles of FcCypA in hemocytes and hepatopancreas could be significantly induced by the stimulation of Vibrio anguillarum suspension and white spot syndrome virus (WSSV) stock, which verifies that CypA has an effect on viral and bacterial infection in shrimps. These results indicate that CypA may be involved in the innate immunity, biological immune response and physiological stress response of Chinese shrimps. [ABSTRACT FROM AUTHOR]

C-type lectins (CTLs) are glycan-binding pattern recognition receptors (PRRs) that can bind to carbohydrates on pathogen surfaces, triggering immune responses in shrimp innate immunity. In this study, a unique Ca2+-inhibited CTL named Fc Lec was identified and characterized in Chinese shrimp Fenneropenaeus chinensis. The full-length cDNA sequence of Fc Lec was 976 bp (GenBank accession number KU361826), with a 615 bp open reading frame (ORF) encoding 204 amino acids. Fc Lec possesses a C-type lectin-like domain (CTLD) containing four conserved cysteines (Cys105, Cys174, Cys192, and Cys200) and two sugar-binding site structures (QPD and LNP). The tertiary structure of Fc Lec deduced revealed three α-helices and eight β-pleated sheets. The mRNA expression levels of Fc Lec in hemocytes and the hepatopancreas were markedly elevated after stimulation with Vibrio anguillarum and white spot syndrome virus (WSSV). The recombinant Fc Lec protein exhibited Ca2+-independent hemagglutination and bacterial agglutination, but these activities were observed only in the presence of EDTA to chelate metal ions. These findings suggest that Fc Lec plays important and functionally distinct roles in the shrimp's innate immune response to bacteria and viruses, enriching the current understanding of the relationship between CTL activity and Ca2+ in invertebrates. [Display omitted] • A novel CTL, Fc Lec, were identified from F. chinensis. • Fc Lec plays distinct and significant roles in the innate immune system's reaction to microbial assaults. • Fc Lec exhibits Ca2+-independent and even Ca2+-inhibited activity. [ABSTRACT FROM AUTHOR]

Fenneropenaeus chinensis is a commercially important shrimp species cultured in China. This study investigated eight F. chinensis populations in China, including four geographical populations, three commercial breeds, and one wild population captured from the Yellow Sea. Population stratification analysis revealed that the Hebei geographical population and commercial breeding "Huanghai No. 4" were relatively independent and stable, reflecting a relatively closed breeding environment, whereas gene introgression was present between other populations. Selective signature analysis detected artificial selection for vision, growth, and disease resistance in the Hebei population. Neuronal development-related genes were detected to be under selection in the Changyi and Rizhao populations. Fertility of the Rizhao population was also investigated. Additionally, genes in the glycosaminoglycan biosynthesis-chondroitin sulfate/dermatan sulfate pathway were involved in the high pH tolerance of the "Huanghai No. 4" population. This study provided support for the genetic mechanism of parsing economic traits and the development of molecular breeding technologies. • Eight F. chinensis geographical populations and commercial breeds were collected. • Hebei population and Huanghai No. 4 were relatively independent and stable. • Vision, growth, neurodevelopment and immunity were selected during domestication. • Glycosaminoglycan biosynthesis pathway involved in the high pH tolerance. [ABSTRACT FROM AUTHOR]

pH has a great impact on the distribution, growth, behavior, and physiology in many aquatic animals. The comparison of proteomics between normal and high pH stress samples was successfully achieved using iTRAQ proteomic analysis to screen key response proteins and pathways. After high pH stress, 124 upregulated and 41 downregulated proteins were identified. The higher expression levels of proteins like citrate synthase, glutathione S-transferase, glutathione peroxidase, and cytochrome c oxidase are associated with oxidative stress and mitochondrial dysfunction. The upregulation of glucose-regulated protein 78 indicated that the endoplasmic reticulum stress is induced by high pH stress. There were significant upregulation expressions of V-type H+-ATPase, Na+, K+-ATPase, 14-3-3 protein, as well as ATP-binding cassette transmembrane transporters after high pH exposure, which indicating their important roles in response to high pH stress. The abundance of proteins involved in protein glycosylation, oxidative pentose phosphate pathway, protein export, and glutathione metabolism were found enriched in high pH group than in control group. Quantitative proteomic profiling and integrated analysis with transcriptomic data provide new insights into the mechanisms underlying the molecular response to high pH stress in Fenneropenaeus chinensis. [ABSTRACT FROM AUTHOR]

The apoptosis of hemocytes plays an essential function in shrimp immune defense against pathogen invasions. In order to further elucidate the differential apoptotic responses of the granulocytes and the hyalinocytes in Fenneropenaeus chinensis post WSSV infection, the characteristics of apoptotic dynamics and viral proliferation in total hemocytes and hemocyte subpopulations were respectively investigated in the present work. The results showed that the apoptotic rate of hemocytes changed significantly, and the apoptosis-related genes also showed significantly differential expression responses during WSSV infection. Interestingly, we found that the apoptotic rate of virus-negative hemocytes was significantly higher than that of virus-positive hemocytes in the early stage of WSSV infection, while it was significantly lower than that of virus-positive cells in the middle and late infection stages. The difference of apoptosis between virus-positive and virus-negative hemocytes seems to be an important way for the WSSV to destroy the host’s immune system and facilitate the virus spread at different infection stages. It was further found that the apoptosis rate of granulocytes was always significantly higher than that of hyalinocytes during WSSV infection, indicating that granulocytes have a stronger apoptotic response to WSSV infection. Moreover, a higher viral load was detected in granulocytes, and the density of granulocytes decreased more rapidly post WSSV infection, indicating that the granulocytes are more susceptible and vulnerable to WSSV infection compared with the hyalinocytes. These results collectively demonstrated that the apoptotic response in shrimp hemocytes was significantly influenced by the WSSV infection, and the differential apoptotic response of granulocytes and hyalinocytes to WSSV indicated the differences of antiviral mechanisms between the two hemocyte subpopulations.

The apoptosis of hemocytes plays an essential function in shrimp immune defense against pathogen invasions. In order to further elucidate the differential apoptotic responses of the granulocytes and the hyalinocytes in Fenneropenaeus chinensis post WSSV infection, the characteristics of apoptotic dynamics and viral proliferation in total hemocytes and hemocyte subpopulations were respectively investigated in the present work. The results showed that the apoptotic rate of hemocytes changed significantly, and the apoptosis-related genes also showed significantly differential expression responses during WSSV infection. Interestingly, we found that the apoptotic rate of virus-negative hemocytes was significantly higher than that of virus-positive hemocytes in the early stage of WSSV infection, while it was significantly lower than that of virus-positive cells in the middle and late infection stages. The difference of apoptosis between virus-positive and virus-negative hemocytes seems to be an important way for the WSSV to destroy the host's immune system and facilitate the virus spread at different infection stages. It was further found that the apoptosis rate of granulocytes was always significantly higher than that of hyalinocytes during WSSV infection, indicating that granulocytes have a stronger apoptotic response to WSSV infection. Moreover, a higher viral load was detected in granulocytes, and the density of granulocytes decreased more rapidly post WSSV infection, indicating that the granulocytes are more susceptible and vulnerable to WSSV infection compared with the hyalinocytes. These results collectively demonstrated that the apoptotic response in shrimp hemocytes was significantly influenced by the WSSV infection, and the differential apoptotic response of granulocytes and hyalinocytes to WSSV indicated the differences of antiviral mechanisms between the two hemocyte subpopulations. [ABSTRACT FROM AUTHOR]

This study provides new insights for the hatchery released Chinese shrimp (Fenneropenaeus chinensis), including proportion, dynamic migration route, after they were released into nature for stock enhancement using a new strategy quite different than ever. Chinese shrimp were sampled at 22 survey stations during two investigation voyages acrossing 74 survey stations in the Bohai Sea from July 16 to August 9 in 2015. Among 289 sampled individuals during the second voyage, totally 155 shrimps were identified as hatchery shrimp released into the Laizhou Bay at mid-May in 2015 based on finger-print of eight SSR (simple sequence repeats) markers, and the proportion of hatchery released shrimp in recapture samples were from 41.30%–85.71% in each station with an average value 53.63%, which verified a previous view point that up to 90% of autumn season Chinese shrimp landing in the Bohai Sea were composed of hatchery released. Meanwhile, the dynamic migration route of hatchery released shrimp revealed that part of released shrimp migrated heading northwest along the west coast of the Bohai Sea up to the Bohai Bay but just remained at the Laizhou Bay until over-wintering migration at mid-October when they initiate over-wintering migration. Present unnatural spring season shrimp fishing model cut the throat of spawner shrimp chance to swim back to their respective spawning plants at each spring, it still no chance to clarify whether the hatchery released shrimp could replenish to the reproduce population and complete a whole life cycle as same as their natural relatives. [ABSTRACT FROM AUTHOR]

In our previous work, prohibitin1 (PHB1) was identified to be only expressed in granulocytes of Fenneropenaeus chinensis. In order to elucidate the potential immunological properties of prohibitins in hemocyte subpopulations, in this paper, the full-length cDNAs of PHB1 and PHB2 were firstly cloned from F. chinensis using rapid amplification of cDNA ends approach, and they were designated Fc PHB1 and Fc PHB2, respectively. Based on the sequence analysis and multiple sequence alignment, Fc PHB1 and Fc PHB2 were members of SPFH protein family. By quantitative real-time RT-PCR, the higher mRNA transcription levels of Fc PHB1 and Fc PHB2 were detected in intestine and hemocytes of F. chinensis , and these two genes in hemocytes were significantly up-regulated upon WSSV infection. The Fc PHB1 and Fc PHB2 were recombinantly expressed in Escherichia coli BL21 (DE3), and employed as immunogens to produce the polyclonal antibodies (PAbs) in rabbits. Indirect immunofluorescence assay (IFA) revealed that the Fc PHB1 and Fc PHB2 were located both in the cytoplasm and nuclei of hemocytes, which could also be specifically recognized by the PAbs against Fc PHB1 or Fc PHB2 in Western blot. Interestingly, it was found that Fc PHB1 and Fc PHB2 were only expressed in the granulocytes of heathy shrimp and highly expressed in the WSSV-infected granulocytes, however only weak expressions of Fc PHB1 and Fc PHB2 were observed in the hyalinocytes of WSSV-infected shrimp. Meanwhile, silencing of Fc PHB1 and Fc PHB2 genes were performed by small interfering RNA, and the results showed that the WSSV copies in hemocytes were increased by knockdown of either Fc PHB1 or Fc PHB2, and the cumulative mortalities of shrimp in the silenced groups were also markedly increased. These results demonstrated that Fc PHB1 and Fc PHB2 played important roles in anti-WSSV infection, and their differential expression characteristics in hemocyte subpopulations provided a further understanding of the immune functions of granulocytes and hyalinocytes. • The cDNA sequences of PHB1 and PHB2 of Fenneropenaeus chinensis were cloned and characterized. • Fc PHB1 and Fc PHB2 were significantly up-regulated post WSSV infection. • Fc PHB1 and Fc PHB2 play important roles in inhibiting WSSV infection. • Fc PHB1 and Fc PHB2 were differentially expressed in granulocytes and hyalinocytes. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

pH has a great impact on the distribution, growth, behaviour and physiology in many aquatic animals. MicroRNAs (miRNAs), a class of small non‐coding RNAs play essential roles in animal responses to environmental stress. In this study, we constructed two small RNA (sRNA) libraries from control (pH 7.4) and high pH (9.4) treated shrimp to identify high pH stress‐responsive miRNAs. Using deep sequencing, we identified 72 (3 conserved and 69 novel) up‐ and 4 (2 conserved and 2 novel) down‐regulated miRNAs from high pH challenged shrimp hepatopancreas. Gene Ontology annotations and Kyoto Encyclopedia of Genes and Genomes pathway analysis revealed that these target transcripts were implicated in a broad range of biological processes and various metabolic pathways. Moreover, we validated the expression patterns of selected miRNAs and their target genes by qRT‐PCR. The present work adds new insights into the large‐scale identification and characterization of Fenneropenaeus chinensis miRNAs and their potential targets and represents a foundation for underlying mechanisms of animal responses to high pH stress at post‐transcriptional level. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Raf is a member in the Ras/Raf/MAPKK/MAPK signaling transduction pathway. To obtain a better understanding of Raf in the interaction between the Chinese shrimp Fenneropenaeus chinensis and white spot syndrome virus (WSSV), the sequence of cDNA of Raf from F. chinensis (FcRaf) was obtained. The FcRaf gene contained a 2421 bp open reading frame (ORF). The FcRaf shared most characteristic of Raf protein, such as the Raf-like Ras-binding domain (RBD), phorbol esters/diacylglycerol binding domain (C1 domain), and catalytic domain of the serine/threonine kinases, Raf (STKc_Raf). The sequence of functional domains of Raf protein was relatively conserved. The FcRaf mRNA was detected in the tissues of gill, muscle, and hepatopancreas from normal F. chinensis. The mRNA abundance level of FcRaf in the gill was the highest, which was 2.7-fold the level in the hepatopancreas. The expression level of FcRaf was significantly (P < 0.05) up-regulated in the tissues of gill, muscle, and hepatopancreas post WSSV-infection, which suggested that FcRaf might be involved in the interaction between F. chinensis and WSSV. Two SNP loci were identified in the ORF, one of which was a C-T mis-sense mutation, where an Ala was replaced by a Val, and induced the predicted protein secondary structure change. Considering the relatively low MAF (0.07), whether this mis-sense mutation was a detrimental mutation needs further investigation. Highlights • A cDNA encoding Raf from Fenneropenaeus chinensis (FcRaf) was cloned and sequenced for the first time. • The sequence of functional domains of FcRaf protein was relatively conserved. • The FcRaf mRNA abundance level in tissues fluctuated post WSSV challenge. • Two SNPs were identified in the FcRaf ORF and one of which was a mis-sense mutation. [ABSTRACT FROM AUTHOR]

Abstract Response surface methodology coupled with a Box-Behnken design (RSM-BBD) was used to optimize neutrase concentration (A: 4–6% (w/w)), liquid-solid ratio (B: 10–20 mL/g) and hydrolysis time (C: 3–5 h) to obtain shrimp shell wastes hydrolysates with α-amylase inhibitory activity. The optimum conditions were enzyme concentration of 5.4% (w/w), liquid-solid ratio of 13 mL/g, time of 4.1 h, temperature of 50 °C and pH of 7.0. Under these conditions, the α-amylase inhibitory rate was 43.4%, in agreement with the prediction model with a coefficient of determination (R2) of 0.9676. Shrimp shell wastes hydrolysates showed significant ability to scavenge diphenyl picryl hydrazinyl free radicals, reduce iron (III) and inhibit lipid peroxidation. Shrimp shell waste hydrolysates consisted mainly of small peptides with molecular weights less than 4 kDa and high essential amino acids (278 mg/g), which indicated its high nutritional value based on the FAO/WHO recommended standard protein. The results showed that shrimp shell waste hydrolysates contained valuable components that could be converted into useful and potentially high-value products. Graphical abstract fx1 Highlights • A Box-Behnken Design (BBD) was used to obtain shrimp shell waste hydrolysates (SSWH) with α-amylase inhibitory activity. • Optimal conditions occurred at neutrase concentration of 5.4% (w/w), liquid-solid ratio of 13 mg/mL and time of 4.1 h. • SSWH may be used as a nutritional food resource with α-amylase inhibition activity and high essential amino acids. [ABSTRACT FROM AUTHOR]

In our previous study, the differentially expressed proteins have been identified by proteomic analysis in total haemocytes of shrimp ( Fenneropenaeus chinensis ) after white spot syndrome virus (WSSV) infection. To further investigate the differential response of haemocyte subpopulations to WSSV infection, granulocytes and hyalinocytes were separated from healthy and WSSV-infected shrimp by immunomagnetic bead (IMB) method, respectively. Then two-dimensional gel electrophoresis (2-DE) and mass spectrometry (MS) were used to analyze the differentially expressed proteins in haemocyte subpopulations between healthy and WSSV-infected shrimp. The results of flow cytometry (FCM) showed that about 98% of granulocytes and about 96% of hyalinocytes in purity were obtained. Quantitative intensity analysis revealed that 26 protein spots in granulocytes and 24 spots in hyalinocytes were significantly changed post WSSV infection. Among them, 24 proteins in granulocytes and 23 proteins in hyalinocytes were identified by MS analysis, which could be divided into eight categories according to Gene Ontology. The identification of prophenoloxidase (proPO), proPO 2 and peroxiredoxin in WSSV-infected granulocytes was consistent with the facts that the proPO-activating system and peroxiredoxin were mainly existed in granulocytes. The phagocytosis of hyalinocytes seemed to be enhanced during the infection, because several proteins that involved in phagocytosis, including clathrin heavy chain, ADP ribosylation factor 4 and Alpha2 macroglobulin were up-regulated in hyalinocytes upon WSSV infection. Our results also reflected the vital biological significance of calcium ion binding proteins in granulocytes and ATPase/GTPase in hyalinocytes during WSSV infection. The data in this study verified the roles of granulocytes and hyalinocytes involved in WSSV infection, and differentially expressed proteins identified in granulocytes and hyalinocytes had a close correlation with their function characteristics. [ABSTRACT FROM AUTHOR]

In the present study, Fenneropenaeus chinensis individuals were assigned into six groups, and fed with a diet supplemented with 0 (Control), 0.5% (Group K ), 1.0% (Group E0.5), 2.0% (Group E20), 3.0% (Group E30 .) or 5.0% (Group E 50) of poly-β-hydroxybutyrate (PHB) during their growth and spawning periods, to explore the effect of PHB on the reproductive performance of parents and the development of larvae. The experiment was lasted for 192 d to measure the mortality rate, relative percentage of survival(RPS), weight gain rate(WGR), specific growth rate (SGR) and cycle of gonadal development of parental shrimps, number of eggs, number of nauplii, stages of larval development and metamorphosis. The results indicated that PHB had an obvious effect on the fecundity of parental shrimps and growth performance of larva. Compared with control group, the mortality rate of broodstock in experimental groups decreased initially and increased subsequently with the increase of PHB concentration, while RPS showed an opposite pattern. The mortality rate of group E20 was the lowest among all groups, showing significant difference from that of other groups(P < 0.05) except group E (P > 0.05). WGR of all experimental groups was higher than that of the control group, among which, group E50 and group E10, had significantly higher WGR than the control (P<0.05). However, there was no significant difference in the cycle of gonadal development between the experimental groups and the control group (P > 0.05). The numbers of eggs and nauplii in the experimental groups were higher than those of the control group. And the numbers of eggs and nauplii in group E were significantly higher than those of the control (P < 0.05), bud showed no significant difference from those of other groups (P > 0.05). However, there was no significant difference in the duration of larval development and metamorphosis among all the groups. In summary, PHB is capable of improving the reproductive performance of parents and the survival and development of larva in F. chinensis, and 2.0% is the optimal concentration of PHB supplemented to the diet. [ABSTRACT FROM AUTHOR]

The artificial propagation and release of Fenneropenaeus chinensis have been conducted over the past three decades in China. To examine the current population genetic diversity and variability of F. chinensis , six broodstock populations and two wild populations from Chinese coastal waters were collected, and nine microsatellite loci were analyzed. High genetic diversity was found for the eight F. chinensis populations. Inbreeding coefficient ( F is ) estimates were all positive (0.215–0.317), suggesting that inbreeding occurs in this species. A total of 36 (50%) tests deviated from Hardy-Weinberg equilibrium, and all these loci showed evidence of a null allele. Low genetic differentiation among some F. chinensis populations was detected, which is consistent with the microsatellite DNA results of previous studies. A changing geographic pattern was detected for the F. chinensis population, and stock enhancement activity should be focused on F. chinensis because positive inbreeding coefficients were found. [ABSTRACT FROM AUTHOR]

Mitogen-activated protein kinase (MAPK) signaling pathway plays an important role in cellular response to inflammatory cytokines, environmental stress and pathogenic infection, However, compared with mammals and insects, the potential function of p38 MAPK from Chinese shrimp ( Fenneropenaeus chinensis ) in response to viruses and bacterial infection is limited. In the study, the immune responses of four genes MKK3, MKK4, p38 and ATF-2 from F. chinensis were investigated in defending against white spot syndrome virus (WSSV), Vibrio anguillarum ( V. anguillarum ) and Staphylococcus aureus ( S. aureus ) infection. Results demonstrated that the expression levels of these four genes were apparently modulated in hemocytes and gills when shrimp were stimulated by WSSV or bacteria, particularly at 3–24 h after infection. MKK3, p38 and ATF-2 were most sensitive to V. anguillarum (Gram-negative bacteria), followed by WSSV and S. aureus (Gram-positive bacteria), while MKK4 gene was most sensitive to S. aureus , followed by WSSV and V. anguillarum . Knockdown of Fcp38 by RNA interference (RNAi) resulted in a reduction in the expression of FcMKK3 and FcATF-2 . The results indicate that p38MAPK signaling pathway plays a role in defending against viral and bacterial infections in F. chinensis . [ABSTRACT FROM AUTHOR]

Chinese white shrimp Fenneropenaeus chinensis is a commercially important species in northern China and Korea. In the present study, the genetic diversity of five populations collected from Qingdao (QD), Rizhao (RZ) of China, and Narodo Island (KN), Taean (KT), Yeongguang (KY) of Korea in the Yellow Sea was investigated using the mitochondrial control region (CR). The length of the amplified partial mitochondrial control region (mtCR) ranged from 600 to 622 bp, and the sequence variations were distributed among 13 polymorphic sites. The pattern of nucleotide substitution was biased in favour of transitions over transversions in variable sites, including 12 transitions (si, 4 A↔G and 8 T↔C changes) and only one was transversion (sv, 1 T↔G changes). Altogether, 24 unique haplotypes were identified from five populations in Yellow Sea. The overall haplotype diversity and nucleotide diversity were 0.368 - 0.421 and 0.052 - 0.079, respectively, and the lowest genetic diversity was found in QD population. There was no differentiation between the two Chinese populations (FST = 0.039). Within the Korean populations, there was a slight differentiation (FST = 0.075, p < 0.05) between KN and KT. The relative bigger differentiation was shown between RZ and KN population (FST = 0.170, p < 0.05). The relative further genetic distance was shown between RZ and KN population as well as between QD and KN population, while the relative closer genetic distance was shown between KT and KY, and between KT and RZ population. The low variability in the mitochondrial control region among F. chinensis in the Yellow Sea indicated the low genetic diversity in comparison to other shrimp species. The results suggested a slight population differentiation among F. chinensis populations. Such information will assist in sustainable use, management, and conservation of the species

In our previous work, granulocytes and hyalinocytes were successfully separated by immunomagnetic bead (IMB) method using monoclonal antibodies (mAbs) against granulocytes of shrimp ( Fenneropenaeus chinensis ). In order to elucidate the proteomic differentiation between granulocytes and hyalinocytes, in this paper, the differentially expressed proteins were analyzed between non-fixed/un-permeabilized (NFP) haemocytes and fixed/permeabilized (FP) haemocytes using two-dimensional gel electrophoresis (2-DE) combined with mass spectrometry (MS). Then the FP haemocytes were separated into two haemocyte subpopulations using IMB method, and the comparative proteome between granulocytes and hyalinocytes was investigated. The results showed that 10 differentially expressed protein spots were detected and identified as 4 proteins in the NFP haemocytes. Twenty one differentially expressed proteins were successfully identified between granulocytes and hyalinocytes, which include 4 unique expressed proteins in granulocytes, 4 significantly highly expressed proteins in granulocytes, and 13 significantly high expressed proteins in hyalinocytes. According to Gene Ontology annotation, the identified proteins between granulocytes and hyalinocytes were classified into six categories, including binding proteins, proteins involved in catalytic activity, enzyme regulator activity, structural molecule activity, translation regulator activity, and ungrouped proteins. Furthermore, quantitative PCR confirmed that the trend of transcription levels of three selected genes were consistent with the proteomic data from 2-DE. The results may lead to better understanding of the functions of haemocyte subpopulations. [ABSTRACT FROM AUTHOR]

[Objective] This study was carried out to explore the effect of poly-β-hydroxybutyrate(PHB) on the performance of the nonspecific immune system in Fenneropenaeus chinensis. [Method] F. chinensis individuals were assigned into six groups, and each group was fed with a diet containing 0(Control), 0.5%(Group E0.5), 1.0%(Group E1.0), 2.5%(Group E2.5), 5.0%(Group E5.0) or 10.0% PHB(Group E10.0). The mortality rate and relative percent of survival(RPS) of each group were calculated after 6 weeks. Meanwhile, the total antioxidant capacity(T-AOC), the activity of acid phosphatase(ACP), peroxidase(POD) and catalase(CAT), and the content of malondialdehyde(MDA) in hepatopancreas and serum were measured,and their correlation with PHB concentration was analyzed. [Result] The RPS in PHB treated shrimps increased initially and decreased subsequently with increasing PHB concentration. RPS of Group E1.0 was the highest, showing significant difference from that of other groups( P <0.05).With the increase in PHB concentration, the activity of immunity related enzymes changed in a similar pattern with RPS: increasing at first and decreasing subsequently. In addition, the activity of the enzymes was elevated in the 2nd and 3rd weeks of PHB administration. Among them, T-AOC in serum of groups E1.0 and E2.5, T-AOC in hepatopancreas of Group E1.0, ACP activity in serum of groups E1.0 and E2.5, ACP activity in hepatopancreas of Group E1.0, CAT activity in groups E0.5, E1.0 and E2.5, CAT activity in hepatopancreas of groups E0.5, E1.0 and E10.0, POD activity in both serum and hepatopancreas of groups E0.5, E1.0 and E2.5, SOD activity in both serum and hepatopancreas of Group E1.0, MDA content in serum of Group E1.0 and MDA content in hepatopancreas of groups E0.5 and E1.0 showed significant difference from those of other groups(P<0.05). [Conclusion] PHB can improve the immunity of F. chinensis, 1.0% in feed has the best effect, and the total enzyme activity reaches the highest level in the 2nd and 3rd weeks of PHB administration. [ABSTRACT FROM AUTHOR]

In relation to the stock enhancement program for Chinese white shrimp Fenneropenaeus chinensis, hatchery-released juveniles and wild samples in the Yellow Sea and Bohai Sea were genotyped using amplified fragment length polymorphism (AFLP) markers to investigate the levels of genetic variation among these populations. Five AFLP primer combinations generated a total of 757 bands across the 268 individuals in nine hatchery-released populations and three wild populations. All 757 bands were polymorphic. High polymorphism at AFLP markers was found within both hatchery-released and wild populations. The percentage of polymorphic loci for populations ranged from 87.22 to 98.60%, while the Nei's genetic diversity ranged from 0.1822 to 0.2728. Compared with wild populations, the nine hatchery-released populations showed significant genetic changes based on F values. All populations were divided into two distinct groups by principal coordinate analysis (PcoA) analysis. Three wild populations (Dalian, Kengli, Middle Yellow Sea) with hatchery-released populations from Rongcheng, Panjin, and Dandong clustered as one group; the rest of hatchery populations formed another group. Interestingly, no obvious geographic cluster was found in the unweighted pair group method with arithmetic mean tree and PcoA. We recommend monitoring the genetic variability of selected hatchery populations to enhance the conservation of natural Chinese white shrimp F. chinensis resources. [ABSTRACT FROM AUTHOR]