Identification of structural variation related to spawn capability of Penaeus vannamei.

BACKGROUND: The genetic basis underlying spawning abilities in the Pacific white shrimp, Penaeus vannamei, remains largely unexplored. To investigate genetic variations potentially related to reproductive performance, a systematic bioinformatic analysis was conducted to identify structural variations (SVs) with different polymorphic spectra in P. vannamei with high fertility (HF) and low fertility (LF). RESULTS: A total of 2,323 and 1,859 SV events were identified exclusively in the HF and LF groups, respectively. These SVs were mapped to 277 genes in the HF group and 231 genes in the LF group. Gene Ontology (GO) enrichment analysis based on SNPs (single nucleotide polymorphism) and SVs revealed several neural-related processes, suggesting the importance of neural regulation in reproduction. Notably, we identified a set of promising genes, including Cttn, Spast, Ppp4c, Spire1, Lhcgr, and Ftz-f1, which may enhance fertility in shrimp. CONCLUSION: In conclusion, this study is the first to establish a link between SVs and reproductive traits in P. vannamei. The promising genes discovered have the potential to serve as crucial markers for enhancing reproductive traits through targeted genotyping.

Genomic mining of Vibrio parahaemolyticus highlights prevalence of antimicrobial resistance genes and new genetic markers associated with AHPND and tdh + /trh + genotypes.

BACKGROUND: Acute Hepatopancreatic Necrosis Disease (AHPND) causes significant mortality in shrimp aquaculture. The infection is primarily instigated by Vibrio parahaemolyticus (Vp) strains carrying a plasmid encoding the binary toxin PirAB. Yet, comprehension of supplementary virulence factors associated with this relatively recent disease remains limited. Furthermore, the same holds for gastroenteritis in humans caused by other Vp genotypes. Additionally, given the prevalent use of antibiotics to combat bacterial infections, it becomes imperative to illuminate the presence of antimicrobial resistance genes within these bacteria. RESULTS: A subsampled number of 1,036 Vp genomes was screened for the presence of antimicrobial resistance genes, revealing an average prevalence of 5 ± 2 (SD) genes. Additional phenotypic antimicrobial susceptibility testing of three Vp strains (M0904, TW01, and PV1) sequenced in this study demonstrated resistance to ampicillin by all tested strains. Additionally, Vp M0904 showed multidrug resistance (against ampicillin, tetracycline, and trimethoprim-sulfamethoxazole). With a focus on AHPND, a screening of all Vibrio spp. for the presence of pirA and/or pirB indicates an estimated prevalence of 0.6%, including four V. campbellii, four V. owensii, and a Vibrio sp. next to Vp. Their pirAB-encoding plasmids exhibited a highly conserved backbone, with variations primarily in the region of the Tn3 family transposase. Furthermore, an assessment of the subsampled Vp genomes for the presence of known virulence factors showed a correlation between the presence of the Type 3 Secretion System 2 and tdh, while the presence of the Type 6 Secretion System 1 was clade dependent. Furthermore, a genome-wide association study (GWAS) unveiled (new) genes associated with pirA, pirB, tdh, and trh genotypes. Notable associations with the pirAB genotype included outer membrane proteins, immunoglobulin-like domain containing proteins, and toxin-antitoxin systems. For the tdh + /trh + genotypes (containing tdh, trh, or both genes), associations were found with T3SS2 genes, urease-related genes and nickel-transport system genes, and genes involved in a 'minimal' type I-F CRISPR mechanism. CONCLUSIONS: This study highlights the prevalence of antimicrobial resistance and virulence genes in Vp, identifying novel genetic markers associated with AHPND and tdh + /trh + genotypes. These findings contribute valuable insights into the genomic basis of these genotypes, with implications for shrimp aquaculture and food safety.

Molecular Approaches Detect Early Signals of Programmed Cell Death in Hippolyte inermis Leach.

The protandric shrimp Hippolyte inermis is the only known marine invertebrate whose sex determination is strongly influenced by the composition of its food. In H. inermis, a sex reversal is triggered by the ingestion of diatoms of the genus Cocconeis associated with leaves of the seagrass Posidonia oceanica. These diatoms contain compounds that promote programmed cell death (PCD) in H. inermis and also in human cancer cells. Transcriptomic analyses suggested that ferroptosis is the primary trigger of the shrimp's sex reversal, leading to the rapid destruction of the androgen gland (AG) followed by a chain of apoptotic events transforming the testes into ovaries. Here, we propose a molecular approach to detect the effects of compounds stimulating the PCD. An RNA extraction method, suitable for young shrimp post-larvae (five days after metamorphosis; PL5 stage), was established. In addition, six genes involved in apoptosis, four involved in ferroptosis, and seven involved in the AG switch were mined from the transcriptome, and their expression levels were followed using real-time qPCR in PL5 fed on Cocconeis spp., compared to PL5 fed on a basic control feed. Our molecular approach, which detected early signals of sex reversal, represents a powerful instrument for investigating physiological progression and patterns of PCD in marine invertebrates. It exemplifies the physiological changes that may start a few days after the settlement of post-larvae and determine the life destiny of an individual.

Low salinity stress increases the risk of Vibrio parahaemolyticus infection and gut microbiota dysbiosis in Pacific white shrimp.

BACKGROUND: Extreme precipitation events often cause sudden drops in salinity, leading to disease outbreaks in shrimp aquaculture. Evidence suggests that environmental stress increases animal host susceptibility to pathogens. However, the mechanisms of how low salinity stress induces disease susceptibility remain poorly understood. METHODS: We investigated the acute response of shrimp gut microbiota exposed to pathogens under low salinity stress. For comparison, shrimp were exposed to Vibrio infection under two salinity conditions: optimal salinity (Control group) and low salinity stress (Stress group). High throughput 16S rRNA sequencing and real-time PCR were employed to characterize the shrimp gut microbiota and quantify the severity level of Vibrio infection. RESULTS: The results showed that low salinity stress increased Vibrio infection levels, reduced gut microbiota species richness, and perturbed microbial functions in the shrimp gut, leading to significant changes in lipopolysaccharide biosynthesis that promoted the growth of pathogens. Gut microbiota of the bacterial genera Candidatus Bacilliplasma, Cellvibrio, and Photobacterium were identified as biomarkers of the Stress group. The functions of the gut microbiota in the Stress group were primarily associated with cellular processes and the metabolism of lipid-related compounds. CONCLUSIONS: Our findings reveal how environmental stress, particularly low salinity, increases shrimp susceptibility to Vibrio infection by affecting the gut microbiota. This highlights the importance of avoiding low salinity stress and promoting gut microbiota resilience to maintain the health of shrimp.

Pretreatment with Liposome-Encapsulated Shrimp Shell Extract Attenuated Neuronal Damage and Death in Aß1-42-Induced Memory Deficits in Rats.

The accumulation of amyloid-beta (Aß) peptides is a crucial factor in the neuronal degeneration of Alzheimer's disease (AD). The current study investigated the underlying neuroprotective mechanisms of shrimp shell extract (SSE) and liposome-encapsulated SSE (SSE/L) against Aß1-42-induced neuronal damage and death in rats. Intracerebroventricular infusion of Aß1-42 effectively induced memory decline, as observed in a reduction of the rat's discriminating ability in the novel object recognition and novel object location tasks. Oral pretreatment with 100 mg/kg of SSE demonstrated no preventive effect on the memory decline induced by Aß1-42 infusion. However, treatment with SSE/L 100 mg/kg BW effectively attenuated memory deficits in both behavioral assessments following two and four weeks after Aß1-42 infusion. Moreover, SSE/L exerted neuroprotective effects by reducing lipid peroxidation and increasing Nrf2/HO-1 expression. There was a significant decrease in Iba1 and GFAP (biomarkers of microglia and astrocyte activity, respectively), as well as a decrease in the levels of NF-κB expression and the inflammatory cytokines TNF-α and IL-6 in the cortical and hippocampal tissues. Treatment with SSE/L also reduced the pro-apoptotic proteins Bax and cleaved caspase-3 while raising the anti-apoptotic protein Bcl2. In addition, the beneficial effects of SSE/L were along with the effects of a positive control commercial astaxanthin (AST). The findings of this study indicated that SSE/L provided neuroprotective effects on Aß1-42-induced AD rats by ameliorating oxidative stress, neuroinflammation and apoptotic cell death. Therefore, SSE/L might be employed to prevent and mitigate Aß accumulation-induced neurotoxicity in AD.

Genome mining and physiological analyses uncover adaptation strategies and biotechnological potential of Virgibacillus dokdonensis T4.6 isolated from high-salt shrimp paste.

Virgibacillus spp. stand out as a potent starter culture for accelerating the fermention of fish sauces and shrimp pastes. However, the underlying molecular mechanisms responsible for their adaptation and biotechnological potential remain elusive. Therefore, the present study focuses on phenotypic and genomic analyses of a halophilic bacterium Virgibacillus dokdonensis T4.6, derived from Vietnamese high-salt fermented shrimp paste. The draft genome contained 4,096,868 bp with 3780 predicted coding sequences. Genome mining revealed the presence of 143 genes involved in osmotic adaptation explaining its resistant phenotype to 24% (w/v) NaCl. Among them, 37 genes making up the complete ectoine metabolism pathway, confirmed its ability to produce 4.38 ± 0.29 wt% ectoine under 12.5% NaCl stress. A significant finding was the identification of 39 genes responsible for an entire degradation pathway of the toxic biogenic amine histamine, which was in agreement with its histamine degradation rate of 42.7 ± 2.1% in the HA medium containing 5 mM histamine within 10 days at 37 °C. Furthermore, 114 proteolytic and 19 lipolytic genes were detected which might contribute to its survival as well as the nutrient quality and flavor of shrimp paste. Of note, a putative gene vdo2592 was found as a possible novel lipase/esterase due to its unique Glycine-Aspartate-Serine-Leucine (GDSL) sequence motif. This is the first report to reveal the adaptative strategies and related biotechnological potential of Virgibacillus associated with femented foods. Our findings indicated that V. dokdonensis T4.6 is a promising starter culture for the production of fermented shrimp paste products.

Pleionea litopenaei sp. nov., isolated from the gastric tract of juvenile Pacific white shrimp Litopenaeus vannamei.

A Gram-stain-negative, aerobic, rod-shaped and motile strain HL-JVS1T, was isolated from the gastric tract of a juvenile Pacific white shrimp. Molecular phylogenetic analysis based on 16S rRNA gene sequences of strain HL-JVS1T revealed its affiliation with the genus Pleionea, with close relatives including Pleionea mediterranea MOLA115T (97.5%) and Pleionea sediminis S1-5-21T (96.2%). The complete genome of strain HL-JVS1T consisted of a circular 4.4 Mb chromosome and two circular plasmids (6.6 and 35.0 kb) with a G + C content of 43.1%. The average nucleotide identity and digital DNA-DNA hybridization values between strain HL-JVS1T and the type strains of described Pleionea species were 69.7-70.4% and 18.3-18.6%, respectively. Strain HL-JVS1T grew at 10-40 °C (optimum, 30 °C) in the presence of 0.5 - 9.0% (w/v) sea salts (optimum, 2.0 - 2.5%), and at pH range of 5.5 - 10.0 (optimum, pH 6.5). The major fatty acids (> 10%) were summed feature 9 (iso-C17:1 ω9c and/or C16:0 10-methyl) (23.3%), iso-C16:0 (14.5%), iso-C11:0 3-OH (13.8%) and iso-C15:0 (11.0%). The polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, an unidentified aminophospholipid, two unidentified aminolipids, and two unidentified lipids. The respiratory quinone was ubiquinone-8. The comprehensive phylogenetic, phylogenomic, phenotypic and chemotaxonomic results showed that strain HL-JVS1T is distinct from other Pleionea species. Hence, we propose strain HL-JVS1T as a novel species belonging to the genus Pleionea, for which the name Pleionea litopenaei sp. nov. is proposed with HL-JVS1T (= KCCM 90514T = JCM 36490T) as the type strain.

OXPHOS capacity is diminished and the phosphorylation system inhibited during diapause in an extremophile, embryos of Artemia franciscana.

Diapause exhibited by embryos of Artemia franciscana is accompanied by severe arrest of respiration. A large fraction of this depression is attributable to downregulation of trehalose catabolism that ultimately restricts fuel to mitochondria. This study now extends knowledge on the mechanism by revealing metabolic depression is heightened by inhibitions within mitochondria. Compared with that in embryo lysates during post-diapause, oxidative phosphorylation (OXPHOS) capacity P is depressed during diapause when either NADH-linked substrates (pyruvate and malate) for electron transfer (electron transfer capacity, E) through respiratory Complex I or the Complex II substrate succinate are used. When pyruvate, malate and succinate were combined, respiratory inhibition by the phosphorylation system in diapause lysates was discovered as judged by P/E flux control ratios (two-way ANOVA; F1,24=38.78; P<0.0001). Inhibition was eliminated as the diapause extract was diluted (significant interaction term; F2,24=9.866; P=0.0007), consistent with the presence of a diffusible inhibitor. One candidate is long-chain acyl-CoA esters known to inhibit the adenine nucleotide translocator. Addition of oleoyl-CoA to post-diapause lysates markedly decreased the P/E ratio to 0.40±0.07 (mean±s.d.; P=0.002) compared with 0.79±0.11 without oleoyl-CoA. Oleoyl-CoA inhibits the phosphorylation system and may be responsible for the depressed P/E in lysates from diapause embryos. With isolated mitochondria, depression of P/E by oleoyl-CoA was fully reversed by addition of l-carnitine (control versus recovery with l-carnitine, P=0.338), which facilitates oleoyl-CoA transport into the matrix and elimination by ß-oxidation. In conclusion, severe metabolic arrest during diapause promoted by restricting glycolytic carbon to mitochondria is reinforced by depression of OXPHOS capacity and the phosphorylation system.

Compound isolation through bioassay-guided fractionation of Tectona grandis leaf extract against Vibrio pathogens in shrimp.

Tectona grandis Linn, commonly known as teak, is traditionally used to treat a range of diseases, including the common cold, headaches, bronchitis, scabies, diabetes, inflammation, and others. The present study was conducted with the purpose of isolating and identifying the active compounds in T. grandis leaf against a panel of Vibrio spp., which may induce vibriosis in shrimp, using bioassay-guided purification. The antimicrobial activity was assessed using the microdilution method, followed by the brine shrimp lethality assay to determine toxicity. Following an initial screening with a number of different solvents, it was established that the acetone extract was the most effective. The acetone extract was then exposed to silica gel chromatography followed by reversed-phase HPLC and further UHPLC-orbitrap-ion trap mass spectrometry to identify the active compounds. Three compounds called 1-hydroxy-2,6,8-trimethoxy-9,10-anthraquinone, deoxyanserinone B, and khatmiamycin were identified with substantial anti-microbial action against V. parahaemolyticus, V. alginolyticus, V. harveyi, V. anguillarum, and V. vulnificus. The IC50 values of the three compounds viz. 1-hydroxy-2,6,8-trimethoxy-9,10-anthraquinone, deoxyanserinone B, and khatmiamycin varied between 2 and 28, 7 and 38, and 7 and 56 µg/mL, respectively, which are as good as the standard antibiotics such as amoxicillin and others. The in vivo toxicity test revealed that the compounds were non-toxic to shrimp. The results of the study suggest that T. grandis leaf can be used as a source of bioactive compounds to treat Vibrio species in shrimp farming.

Metagenomic and metabolomic profiling of dried shrimp (Litopenaeus vannamei) prepared by a procedure traditional to the south China coastal area.

Sun-drying is a traditional process for preparing dried shrimp in coastal area of South China, but its impacts on nutrition and the formation of flavor-contributory substances in dried shrimp remain largely unknown. This study aimed to examine the effects of the production process on the microbiota and metabolites in dried shrimp. 16S rDNA amplicon sequencing was employed to identify 170 operational taxonomic units (OTUs), with Vibrio, Photobacterium, and Shewanella emerging as the primary pathogenic bacteria in shrimp samples. Lactococcus lactis was identified as the principal potential beneficial microorganism to accrue during the dried shrimp production process and found to contribute significantly to the development of desirable shrimp flavors. LC-MS-based analyses of dried shrimp sample metabolomes revealed a notable increase in compounds associated with unsaturated fatty acid biosynthesis, arachidonic acid metabolism, amino acid biosynthesis, and flavonoid and flavanol biosynthesis throughout the drying process. Subsequent exploration of the relationship between metabolites and bacterial communities highlighted the predominant coexistence of Bifidobacterium, Clostridium, and Photobacterium contributing heterocyclic compounds and metabolites of organic acids and their derivatives. Conversely, Arthrobacter and Staphylococcus were found to inhibit each other, primarily in the presence of heterocyclic compounds. This comprehensive investigation provides valuable insights into the dynamic changes in the microbiota and metabolites of dried shrimps spanning different drying periods, which we expect to contribute to enhancing production techniques and safety measures for dried shrimp processing.

Utilizing chitooligosaccharides from shrimp waste biodegradation via recombinant chitinase A: a promising approach for emulsifying hydrocarbon and bioremediation.

BACKGROUND: Hydrocarbon pollution stemming from petrochemical activities is a significant global environmental concern. Bioremediation, employing microbial chitinase-based bioproducts to detoxify or remove contaminants, presents an intriguing solution for addressing hydrocarbon pollution. Chitooligosaccharides, a product of chitin degradation by chitinase enzymes, emerge as key components in this process. Utilizing chitinaceous wastes as a cost-effective substrate, microbial chitinase can be harnessed to produce Chitooligosaccharides. This investigation explores two strategies to enhance chitinase productivity, firstly, statistical optimization by the Plackett Burman design approach to  evaluating the influence of individual physical and chemical parameters on chitinase production, Followed by  response surface methodology (RSM) which delvs  into the interactions among these factors to optimize chitinase production. Second, to further boost chitinase production, we employed heterologous expression of the chitinase-encoding gene in E. coli BL21(DE3) using a suitable vector. Enhancing chitinase activity not only boosts productivity but also augments the production of Chitooligosaccharides, which are found to be used as emulsifiers. RESULTS: In this study, we focused on optimizing the production of chitinase A from S. marcescens using the Plackett Burman design and response surface methods. This approach led to achieving a maximum activity of 78.65 U/mL. Subsequently, we cloned and expressed the gene responsible for chitinase A in E. coli BL21(DE3). The gene sequence, named SmChiA, spans 1692 base pairs, encoding 563 amino acids with a molecular weight of approximately 58 kDa. This sequence has been deposited in the NCBI GenBank under the accession number "OR643436". The purified recombinant chitinase exhibited a remarkable activity of 228.085 U/mL, with optimal conditions at a pH of 5.5 and a temperature of 65 °C. This activity was 2.9 times higher than that of the optimized enzyme. We then employed the recombinant chitinase A to effectively hydrolyze shrimp waste, yielding chitooligosaccharides (COS) at a rate of 33% of the substrate. The structure of the COS was confirmed through NMR and mass spectrometry analyses. Moreover, the COS demonstrated its utility by forming stable emulsions with various hydrocarbons. Its emulsification index remained stable across a wide range of salinity, pH, and temperature conditions. We further observed that the COS facilitated the recovery of motor oil, burned motor oil, and aniline from polluted sand. Gravimetric assessment of residual hydrocarbons showed a correlation with FTIR analyses, indicating the efficacy of COS in remediation efforts. CONCLUSIONS: The recombinant chitinase holds significant promise for the biological conversion of chitinaceous wastes into chitooligosaccharides (COS), which proved its potential in bioremediation efforts targeting hydrocarbon-contaminated sand.

Ago4-piRNA complex is a key component of genomic immune system against transposon expression in Penaeus monodon.

Argonaute proteins are key constituents of small RNA-guided regulatory pathways. In crustaceans, members of the AGO subfamily of Argonaute proteins that play vital roles in immune defense are well studied, while proteins of the PIWI subfamily are less established. PmAgo4 of the black tiger shrimp, Penaeus monodon, though phylogenetically clustered with the AGO subfamily, has distinctive roles of the PIWI subfamily in safeguarding the genome from transposon invasion and controlling germ cell development. This study explored a molecular mechanism by which PmAgo4 regulates transposon expression in the shrimp germline. PmAgo4-associated small RNAs were co-immunoprecipitated from shrimp testis lysate using a PmAgo4-specific polyclonal antibody. RNA-seq revealed a majority of 26-27 nt long small RNAs in the PmAgo4-IP fraction suggesting that PmAgo4 is predominantly associated with piRNAs. Mapping of these piRNAs on nucleotide sequences of two gypsy and a mariner-like transposons of P. monodon suggested that most piRNAs were originated from the antisense strand of transposons. Suppression of PmAgo4 expression by a specific dsRNA elevated the expression levels of the three transposons while decreasing the levels of transposon-related piRNAs. Taken together, these results imply that PmAgo4 exerts its suppressive function on transposons by controlling the biogenesis of transposon-related piRNAs and thus, provides a defense mechanism against transposon invasion in shrimp germline cells.

Immunological lectins in shrimp Penaeus vannamei challenged with infectious myonecrosis virus (IMNV) under low-salinity conditions.

Lectins are proteins capable of recognizing and binding to glycan in a specific way. In invertebrates, lectins are a crucial group of Pattern Recognition Proteins (PRRs), activating cellular and humoral responses in the innate immune system. The shrimp Penaeus vannamei is the main crustacean cultivated worldwide, however, the productivity of cultures is strongly affected by diseases, mainly viral ones, such as Infectious Myonecrosis (IMN). Thus, we investigated the participation of five lectins (LvAV, LvCTL4, LvCTL5, LvCTLU, and LvLdlrCTL) in IMNV-challenged shrimp. We verified upregulation gene profiles of lectins after IMNV-challenge, especially in hepatopancreas and gills, in addition to an increase in total hemocytes count (THC) after to 12 h post-infection (hpi). The bioinformatics characterization also revealed several sites of post-translational modification (PTM), such as phosphorylation and glycosylation, which possibly influence the action and stabilization of these lectins. We conclude that LvLdlrCTL and LvCTL5 are the lectins with greater participation in the activation of the immune system against IMNV, showing the greatest potential for PTM, higher upregulation levels, and overlapping with the THC and IMNV viral load.

Survival, immune response and growth of Penaeid shrimp as affected by immunostimulants: A meta-analysis.

Immunostimulants represent the most innovative approach for combating shrimp diseases. They are molecules that effectively enhance the host's nonspecific defenses against invading microorganisms. However, methodological differences exist among immunostimulants based on the same source. Therefore, conducting a meta-analysis is essential to derive valid conclusions. The effect size value utilized in this study was Hedges' d. Heterogeneity among studies was assessed using the DerSimonian and Laird tests (Q-statistic). Meta-regression analysis was conducted to explore the sources of heterogeneity in treatment effects. In this study, dose served as a covariate because it was the only continuous variable that significantly contributed to the observed heterogeneity. Funnel plots and the fail-safe number were employed to assess publication bias within the datasets. The article collection process followed the PRISMA methodology. Based on the results of the meta-analysis and meta-regression conducted with 83 articles, it can be concluded that immunostimulants have a significant effect, characterized by high category standard mean difference (SMD) values, on the survival, growth, and immune response of Penaeid family shrimp. Among potential immunostimulants options, algae ingredients exhibited the most favorable effects on the survival, growth, and immune response of Penaeid family shrimp. Subgroup analysis outcomes revealed that various extraction methods significantly impacted the efficacy of immunostimulants, with the ethanol solvent method proving to be the most effective. Among different administration methods, no significant effect was observed on immunostimulant efficacy across all parameters, with positive SMD values for all administration methods. Regarding challenged test pathogens, immunostimulants were observed to enhance immune response, survival, and weight gain against various pathogens. Meta-regression results indicated that algal treatments had a lower optimal dose point, leading to decreased efficacy as the dose increased. In contrast, fungi exhibited a higher optimum dose point, resulting in increased efficacy at higher doses.

Application of nZnO supported with nanoclay for improving shrimp immunity.

This study discloses the nanoscale silicate platelet-supported nZnO (ZnONSP) applied as novel feed additives in aquaculture. The preparation of the nanohybrid (ZnO/NSP = 15/85, w/w) was characterized by UV-visible spectroscopy, powder X-ray diffraction and transmission electron microscope. The effects of ZnONSP on growth, zinc accumulation, stress response, immunity and resistance to Vibrio alginolyticus in white shrimp (Penaeus vannamei) were \demonstrated. To evaluate the safety of ZnONSP, shrimps (2.0 ± 0.3 g) were fed with ZnONSP containing diets (200, 400 and 800 mg/kg) for 56 days. Dietary ZnONSP did not affect the weight gain, specific growth rate, feed conversion ratio, survival rate, zinc accumulation, and the expression of heat shock protein 70 in tested shrimps. To examine the immunomodulatory effect of ZnONSP, shrimps (16.6 ± 2.4 g) were fed with the same experimental diets for 28 days. Dietary ZnONSP improved the immune responses of haemocyte in tested shrimps, including phagocytic rate, phagocytic index, respiratory burst, and phenoloxidase activity, and upregulated the expression of several genes, including lipopolysaccharide, ß-1,3-glucan binding protein, peroxinectin, penaeidin 2/3/4, lysozyme, crustin, anti-lipopolysaccharide factor, superoxide dismutase, glutathione peroxidase, clotting protein and α-2-macroglobulin. In the challenge experiment, shrimps (17.2 ± 1.8 g) were fed with ZnONSP containing diets (400 and 800 mg/kg) for 7 days and then infected with Vibrio alginolyticus. Notably, white shrimps that received ZnONSP (800 mg/kg) showed significantly improved Vibrio resistance, with a survival rate of 71.4 % at the end of 7-day observation. In conclusion, this study discovers that ZnONSP is a new type of immunomodulatory supplement that are effective on enhancing innate cellular and humoral immunities, and disease resistance in white shrimp.

Function of hemocyanin-mediated succinate dehydrogenase in glucose metabolism and immunity of Penaeus vannamei.

Succinate dehydrogenase (SDH) is a crucial enzyme in the tricarboxylic acid cycle (TCA) and has established roles in immune function. However, the understanding of SDH in Penaeus vannamei, particularly its involvement in immune responses, is currently limited. Through affinity proteomics, a potential interaction between hemocyanin (HMC) and SDH in shrimp has been identified. The successful cloning of PvSDH in this study has revealed a high degree of evolutionary conservation. Additionally, it has been found that hemocyanin regulates SDH not only at the transcriptional and enzymatic levels but also through confirmed protein-protein interactions observed via Co-immunoprecipitation (CoIP) assay. Moreover, by combining PvHMC knockdown and Vibrio parahaemolyticus challenge, it was demonstrated that fumaric acid, a product of SDH, enhances the host's immune resistance to pathogen infection by modulating the expression of antimicrobial peptides. This research provides new insights into HMC as a crucial regulator of SDH, potentially impacting glycometabolism and the dynamics of immune responses.

Unveiling the biofloc culture potential: Harnessing immune functions for resilience of shrimp and resistance against AHPND -causing Vibrio parahaemolyticus infection.

In shrimp aquaculture, disease mitigation may be accomplished by reducing the virulence of the pathogen or by boosting the shrimp's immunity. Biofloc technology is an innovative system that improves the health and resistance of shrimp to microbial infections while providing a viable option for maintaining the quality of culture water through efficient nutrient recycling. This review aimed at demonstrating the efficacy of the biofloc system in boosting the immune responses and protective processes of shrimp against Vibrio parahaemolyticus infection, which is known to cause Acute Hepatopancreatic Necrosis Disease (AHPND). Numerous studies have revealed that the biofloc system promotes the immunological capability of shrimp by raising multiple immune -related genes e.g. prophenoloxidase, serine proteinase gene, ras-related nuclear gene and penaeidinexpression and cellular and humoral responses such as hyperaemia, prophenoloxidase activity, superoxide dismutase activity, phagocytic activity; the protection and survival of shrimp when faced with a challenge from the V. parahaemolyticus strain have been enhanced. Furthermore, the use of the biofloc system improves water quality parameters and potentially bolstering their immune and overall health to effectively resist diseases; hence, promotes the growth of shrimp. The present review suggests that biofloc can serve as an effective therapy for both preventing and supporting the management of probable AHPND infection in shrimp culture. This approach exhibits potential for the progress of sustainable shrimp farming, higher productivity, and improved shrimp health.

Protective effects of butyric acid during heat stress on the survival, immune response, histopathology, and gene expression in the hepatopancreas of juvenile pacific shrimp (L. Vannamei).

This study looked at the effects of adding butyric acid (BA) to the diets of juvenile Pacific shrimp and how it affected their response to survival, immunity, histopathological, and gene expression profiles under heat stress. The shrimp were divided into groups: a control group with no BA supplementation and groups with BA inclusion levels of 0.5 %, 1 %, 1.5 %, 2 %, and 2.5 %. Following the 8-week feeding trial period, the shrimp endured a heat stress test lasting 1 h at a temperature of 38 °C. The results showed that the control group had a lower survival rate than those given BA. Interestingly, no mortality was observed in the group receiving 1.5 % BA supplementation. Heat stress had a negative impact on the activities of alkaline phosphatase (AKP) and acid phosphatase (ACP) in the control group. Still, these activities were increased in shrimp fed the BA diet. Similar variations were observed in AST and ALT fluctuations among the different groups. The levels of triglycerides (TG) and cholesterol (CHO) increased with high temperatures but were reduced in shrimp-supplemented BA. The activity of an antioxidant enzyme superoxide dismutase (SOD) increased with higher BA levels (P < 0.05). Moreover, the groups supplemented with 1.5 % BA exhibited a significant reduction in malondialdehyde (MDA) content (P < 0.05), suggesting the potential antioxidant properties of BA. The histology of the shrimp's hepatopancreas showed improvements in the groups given BA. Conversely, the BA significantly down-regulated the HSPs and up-regulated MnSOD transcript level in response to heat stress. The measured parameters determine the essential dietary requirement of BA for shrimp. Based on the results, the optimal level of BA for survival, antioxidant function, and immunity for shrimp under heat stress is 1.5 %.

Long noncoding RNA profiling in hepatopancreas of Pacific white shrimp and its role in response to white spot syndrome virus infection.

Long noncoding RNA (lncRNA) is a potential regulator of biological processes, including immunity, reproduction, and development. Although several transcriptome studies have focused on responses of viral infections in several organisms, the role of lncRNAs in viral responses in shrimp is still unclear. Therefore, this work aimed to identify putative lncRNAs and study their role in white spot syndrome virus (WSSV) infection in white shrimp. The hepatopancreas transcriptome from WSSV infected shrimp was analyzed in silico to identify putative lncRNAs. Among 221,347 unigenes of the de novo assembled transcriptome, 44,539 putative lncRNAs were identified, 32 of which were differentially expressed between WSSV-infected and control shrimp. Five candidate lncRNAs were validated for their expressions in shrimp tissues and in response to WSSV infection. Lnc164 was chosen for further investigation of its role in WSSV infection. Knockdown of lnc164 prolonged survival of shrimp when challenged with WSSV, suggesting a role in shrimp immunity. In addition, lnc164 was not directly involved in the control of total hemocytes and viral loads in hemolymph of WSSV-infected shrimp. A set of lnc164-regulated genes was obtained by RNA sequencing among which 251 transcripts were differentially expressed between lnc164 knockdown and control shrimp. Six immune-related genes were validated for their expression profiles. Our work sheds light on lncRNA profiles in L. vannamei in response to WSSV infection and paves the way to a functional study of lnc164 in host antiviral response.

The evolutionary adaptation of shrimp hemocyanin subtypes and the consequences on their structure and functions.

Hemocyanin is the main respiratory protein of arthropods and is formed by hexameric and/or oligomeric subunits. Due to changes in the living environment and gene rearrangement, various hemocyanin subtypes and subunits evolved in crustaceans. This paper reviews the various hemocyanin subtypes and isoforms in shrimp and analyses published genomic data of sixteen hemocyanin family genes from Litopenaeus vannamei to explore the evolution of hemocyanin genes, subunits, and protein structure. Analysis of hemocyanin subtypes distribution and structure in various tissues was also performed and related to multiple and tissue-specific functions, i.e., immunological activity, immune signaling, phenoloxidase activity, modulation of microbiota homeostasis, and energy metabolism. The functional diversity of shrimp hemocyanin due to molecular polymorphism, transcriptional regulation, alternative splicing, degradation into functional peptides, interaction with other proteins or genes, and structural differences will also be highlighted for future research. Inferences would be drawn from other crustaceans to explain how evolution has changed the structure-function of hemocyanin and its implication for evolutionary research into the multifunctionality of hemocyanin and other related proteins in shrimp.