White Shrimp Research Articles

Impact of the co-cultivation of macroalgae (Ulva lactuca f. fasciata) on the composition of biofloc in a zero water exchange system used for rearing Pacific white shrimp (Litopenaeus vannamei) (Decapoda, Dendrobranchiata)

Abstract In a closed, or zero water exchange, greenhouse aquaculture system, this study examined the interaction between the aggregation flocs in the mono- and co-cultivation of Pasific white shrimp, Litopenaeus vannamei (300 individuals/m3) with macroalgae, Ulva lactuca f. fasciata at different densities of Ulva (1, 2 and 3 g/l). The investigation was conducted under zero water exchange conditions. The accumulated flocs were compared between the various treatment groups: without Ulva (Treatment Control Group), Ulva at 1 g/l density (T1: Treatment 1), Ulva at 2 g/l (T2: Treatment 2), and Ulva at 3 g/l (T3: Treatment 3). Ultimately, it was determined that Ulva cultivation using the Biofloc system actually helped to ensure the water quality in the zero water exchange culture system during the 35-day experimental period with reduced cyanophyte densities, that can cause toxic algal blooms in aquaculture systems. This was interpreted to result from the fact that Ulva is a naturally occurring bioremediation agent.

Evaluation of Encapsulated Astaxanthin from White Shrimp Shells (Litopenaeus vannamei) on Hepatotoxicity

Recent advances in astaxanthin encapsulation have been reported, but hepatotoxic effect remains unclear. The present investigation therefore aimed to examine the effects of encapsulated astaxanthin from white shrimp shells (Litopenaeus vannamei) on liver toxicity. Wistar rats were divided into 6 groups as control (C), and receiving vitamin E (VE), astaxanthin commercial (AC), astaxanthin extracted from white shrimp shells (AE), astaxanthin encapsulation into powder form (AP), and blank powder (BP). The evaluation of liver in response to astaxanthin administration was then assessed in terms of biochemical parameters and histopathological features. Liver enzymes, aspartate aminotransferase (AST) and alanine aminotransferase (ALT), showed no significant differences among all groups of treatment. Histopathological study showed no abnormal changes on liver tissue including hepatic inflammation. Our data demonstrated that astaxanthin encapsulation did not increase the expression of NF-ҡB nuclear translocation and CYP2E1 in comparison with the control group. Additionally, in this study, the consumption of astaxanthin and vitamin E resulted in a reduction in the oxidative stress index (OSI), while the levels of antioxidant enzymes, including glutathione peroxidase (GPx) and superoxide dismutase (SOD), were significantly increased compared to the control group. Our data suggested that astaxanthin encapsulation does not cause hepatic toxicity, contributing useful information in the applications of astaxanthin encapsulation technology.

Early Spoilage Detection of Cultured Pacific White Shrimp Using Quartz Crystal Microbalance Gas Sensors

AbstractIn this study, quartz crystal microbalance (QCM) gas sensors, coated with electrospun polyvinyl acetate (PVAc) nanofibers, were employed to monitor the spoilage level of cultured Pacific white shrimp. The sensors exhibited a sensitivity range of 0.63 to 1.61 Hz/ppm when detecting trimethylamine vapor, a key biomarker for shrimp spoilage. Significant resonance frequency shifts were observed in the as‐prepared sensors when exposed to amine gases released by long‐stored shrimps. These shifts underline the significance of low‐temperature storage for shrimps. While color changes in the shrimps stored at ambient temperature (25 °C) become noticeable to the naked eye after 6 hours, the sensor detects sample deterioration much earlier, registering a prominent frequency shift (178 Hz) within only 3 hours of storage. This outcome suggests the potential of nanofiber‐coated QCM sensors as early‐stage food freshness indicators.

The interactions between CpG oligodeoxynucleotides and Toll-like receptors in Pacific white shrimp Litopenaeus vannamei

CpG oligodeoxynucleotides (ODNs), as a novel type of adjuvant with immunomodulatory effects, are recognized by Toll-like receptors (TLRs) in Litopenaeus vannamei. In the present study, eleven LvTLRs-pCMV recombinants (rLvTLRs) were constructed to investigate the relationships between various CpG ODNs and different LvTLRs in human embryonic kidney 293T (HEK293T) cells, which was further confirmed by bio-layer interferometry (BLI) technique. The results of dual luciferase reporter assay showed that every LvTLR could activate multiple downstream genes, mainly including NF-κB, CREB, ISRE, IL-6-promoter, TNF-α-promoter and Myc, thereby inducing main signaling pathways in shrimps. Most CpG ODNs possessed affinities to more than one LvTLR, while each LvTLR could recognize multiple CpG ODNs, and the widely recognized ligands within CpG ODNs are A-class and B-class. Moreover, BLI analysis showed that CpG 2216, Cpg 2006, CpG 2143 and CpG 21425 exhibited dose-dependent affinity to the expressed TLR protein, which were consistent with the results in HEK293T cells. It suggested that the interactions of CpG ODNs with LvTLRs were indispensable for the immune regulation triggered by CpG ODNs, and these findings would lay foundations for studying the activations of LvTLRs to immune signaling pathways and shedding lights on the immune functions and mechanisms of CpG ODNs.

Assessment of microplastic contamination in shrimps from the Bay of Bengal and associated human health risk

Microplastics (MPs) were analyzed in seven shrimp species Tiger shrimp (Penaeus monodon), Red tiger shrimp (Caridina cantonensis), Indian shrimp (Penaeus indicus), Red shrimp (Metapenaeus dobsoni), White shrimp (Penaeus merguiensis), Brown shrimp (Metapenaeus monoceros), and Roshna shrimp (Palaemon styliferus) collected from the Bay of Bengal. The abundance and characteristics of MPs were assessed in the gastrointestinal tract (GIT), which certainly translocated to the muscle of shrimp species. The highest MP abundance was found in C. cantonensis with 7.2 items/individual (25.3 items/g in the GIT and 6.3 items/g in muscle). The prominent types of MPs in shrimp samples were fibers (30 %) and fragments (29 %). The ingestion rate of MPs of black and transparent color was comparatively higher, with 64 % of the ingested MPs were < 100 μm. The primary polymer types detected based on Fourier Transform Infrared (FTIR) analysis were Low-Density Polyethylene (LDPE), High-Density Polyethylene (HDPE), Polymethyl Methacrylate (PMMA), Polyvinyl Chloride (PVC), Polypropylene (PP), and Ethylene Vinyl Acetate (EVA). Results from Scanning Electron Microscopy (SEM) showed rough surface textures and adhered particles on the MPs isolated from shrimps. The margin of exposure for females was 71.42, and for males, it was 80.64, indicating that women in Bangladesh are more likely to be exposed to MPs and face a higher risk than men. Sensitivity analysis revealed that MPs particle size was the most sensitive parameter. These findings provide a comprehensive understanding of MP ingestion, human exposure, and contamination in shrimps of Bangladesh, which can help future monitoring efforts.

Detection and partial characterization of antimutagenic compounds from white shrimp (Litopenaeus vannamei) cephalothorax

ABSTRACT Mutations are the result of effects produced by mutagenic agents, which may be responsible for the generation of chronic-degenerative diseases such as cancer. The aim of this work was to detect and characterize compounds with antimutagenic activity in white shrimp (Litopenaeus vannamei) cephalothorax. A serial extraction was carried out where different organic solvents, and its biological activity was evaluated. The antioxidant capacity was evaluated by DPPH and ABTS assay, where the methanol and water-soluble extracts had the highest antioxidant capacity. Antimutagenicity was evaluated by the Ames test, where the methanol-soluble extract showed the highest antimutagenic activity. The methanolic extract was fractionated by open column chromatography, the fractions obtained were determined antioxidant and antimutagenic activity and the ability to protect DNA from oxidative damage. Fraction H27 provided DNA the highest protection against the damage caused by H2O2. Partial chemical-characterization of fraction H27 suggests the presence of aromatic, hydroxylated, unsaturated compounds.

Improving the quality assessment for Pacific white shrimp (Litopenaeus vannamei) stored at 0 °C

AbstractThe quality of Pacific white shrimp stored at 0 °C during the 10 days was evaluated by the combination of sensory, microbiological and biochemical measurements. Quality index methods (QIM) have been developed to evaluate sensory attributes of shrimp. Total visible count (TVC), K value, histamine, and pH are used to assess microbiological and biochemical indices. The results of TVC and QIM showed that shrimps showed signs of spoilage (lg cfu = 6.4; quality index (QI) = 21.37), which is unacceptable to consumers on day 9. QI quality score increased linearly with storage days. The remaining shelf life of shrimp was estimated from the linear regression equation. The results have found the linear regression equations between the QI, histamine, K value, and hypoxanthine. In addition, the results also showed that hypoxanthine could be considered as an independent quality index such as the K index. The quality of Pacific white shrimp could be classified into four grades: excellent, good, moderately acceptable, and just acceptable basing on the results of sensory and biochemical evaluation.

Acute Ammonia Causes Pathogenic Dysbiosis of Shrimp Gut Biofilms.

Acute ammonia exposure has detrimental effects on shrimp, but the underlying mechanisms remain to be fully explored. In the present study, we investigated the impact of acute ammonia exposure on the gut microbiota of the white shrimp Litopenaeus vannamei and its association with shrimp mortality. Exposure to a lethal concentration of ammonia for 48 h resulted in increased mortality in L. vannamei, with severe damage to the hepatopancreas. Ammonia exposure led to a significant decrease in gut microbial diversity, along with the loss of beneficial bacterial taxa and the proliferation of pathogenic Vibrio strains. A phenotypic analysis revealed a transition from the dominance of aerobic to facultative anaerobic strains due to ammonia exposure. A functional analysis revealed that ammonia exposure led to an enrichment of genes related to biofilm formation, host colonization, and virulence pathogenicity. A species-level analysis and experiments suggest the key role of a Vibrio harveyi strain in causing shrimp disease and specificity under distinct environments. These findings provide new information on the mechanism of shrimp disease under environmental changes.

Profile of the gut microbiota of Pacific white shrimp under industrial indoor farming system

The gut microbial communities interact with the host immunity and physiological functions. In this study, we investigated the bacterial composition in Litopenaeus vannamei shrimp’s gut and rearing water under different host (developmental stage: juvenile and adult; health status: healthy and diseased) and environmental factors (temperature 25 °C and 28 °C; and light intensity: low and high). The PCoA analysis showed that all water samples were clustered together in a quarter, whereas the gut samples spread among three quarters. In terms of functional bacteria, gut samples of adult shrimp, healthy adult shrimp, adult shrimp raised at 28 °C, and juvenile shrimp under high light intensity exhibited a higher abundance of Vibrionaceae compared to each other opposite group. Gut samples of juvenile shrimp, infected adult shrimp, juvenile shrimp with low light intensity, and adult shrimp with a water temperature of 25 °C showed a higher abundance of Pseudoaltromonadaceae bacteria compared to each other opposite group. Gut samples of juvenile shrimp, healthy adult shrimp, adult shrimp raised at a water temperature of 28 °C, and juvenile shrimp with high light intensity showed the higher abundance of Firmicutes/Bacteroidota ratio compared to each other opposite group. Our results showed that L. vannamei juveniles are more sensitive to bacterial infections; besides, water temperature of 28 °C and high light intensity groups were both important conditions improving the shrimp gut bacterial composition under industrial indoor farming systems.Key points• Bacteria diversity was higher among shrimp intestinal microbiota compared to the rearing water.• Shrimp juveniles are more sensitive to bacterial infection compared to adults.• Water temperature of 28 °C and high light intensity are recommended conditions for white shrimp aquaculture.Graphical

Unveiling the positive impact of biofloc culture on Vibrio parahaemolyticus infection of Pacific white shrimp by reducing quorum sensing and virulence gene expression and enhancing immunity.

This study aimed to evaluate and unveil the positive impact of biofloc culture on Vibrio parahaemolyticus infection of Pacific white shrimp by reducing quorum sensing (QS) and virulence gene expression and enhancing shrimp's immunity. The shrimp with an average body weight of 0.50 ± 0.09 g were reared in containers with a volume of 2.5 L, 21 units, and a density of 20 shrimp L-1. The shrimp were cultured for 5 days, with each treatment including biofloc system maintenance with a C/N ratio of 10 and a control treatment without biofloc, followed by a challenge test through immersion using V. parahaemolyticus at densities of 103, 105, and 107 CFU mL-1 initially. The results of the invitro experiment showed that biofloc suspension can inhibit and disperse biofilm formation, as well as reduce the exo-enzyme activity (amylase, protease, and chitinase) of V. parahaemolyticus. Furthermore, the biofloc treatment significantly reduced the expression of the QS regulatory gene OpaR, the PirB toxin gene, and the virulence factor genes T6SS1 and T6SS2 in both invitro and invivo. The biofloc system also increased the expression of shrimp immunity-related genes (LGBP, proPO, SP, and PE) and the survival rate of white shrimp challenged with V. parahaemolyticus.

Performance of An Aerated Wastewater Stabilization Pond for the Treatment of Cultivation Wastewater of Pacific White Shrimp (Litopenaeus vannamei) Grow-out Ponds

Pacific white shrimp (Litopenaeus vannamei) is a major cultivated crustacean species whose aquaculture production has doubled in the last decade. The implementation of shrimp pond systems using closed or intensive methods is widely carried out. However, wastewater produced by intensive shrimp farming may cause environmental effects. This study is aimed to evaluate the feasibility of the aerated wastewater stabilization pond to treat the cultivation wastewater. The physicochemical parameters monitored were temperature, pH, salinity, ammonia, nitrite, nitrate and phosphate. In the case of this study, almost all physicochemical parameters of the water coming out of the aerated wastewater stabilization pond are suitable for use as input water for integrated multitrophic aquaculture (IMTA). Temperature, pH, salinity, nitrite, nitrate, and phosphate were 27.1°C to 32.2°C, 7.86 to 8.79, 30 ppt to 34 ppt, 0.003 mg/L to 0.068 mg/L, and 0.19 mg/L to 1.31 mg/L, respectively. Only ammonia concentration significantly fluctuated in the range of 0.44 mg/L to 12 mg/L.

Isolation of Protein from Prawn Shell to Enhance Athletic Performance

Prawns, also known as shrimp, are not only a popular seafood delicacy but also a powerhouse of protein. They boast impressive nutritional profiles, making them a valuable dietary element for both general health and athletic performance. This study explores the potential of protein from white shrimp (Penaeus vannamei) as a natural supplement for athletes. The study used two drying methods: sun-drying for 48 hours and cabinet-drying at 90°C for 8 hours. Higher protein levels were found in the sun-dried samples, making them a potential candidate for superior athletic protein supplementation. Protein was subsequently isolated from this sample. Protein-fortified chocolate was developed to optimize protein consumption. The study reveals the potential of sun-dried Prawnshell (Protein) as a potent and natural muscle-building supplement, aligning with sustainable practices and athlete nutrition.

Effects of myo-inositol on growth and biomarkers of environmental stress and metabolic regulation in Pacific white shrimp (Litopenaeus vannamei) reared at low salinity

This study explored the role of myo-inositol in alleviating the low salinity stress of White Shrimp (Litopenaeus vannamei). Juvenile shrimp (0.4 ± 0.02 g) in low salinity (salinity 3) water were fed diets with myo-inositol levels of 0, 272, 518, 1020 and 1950 mg/kg (crude protein is 36.82 %, crude lipid is 7.58 %), fed shrimp in seawater at a salinity of 25 were fed a 0 mg/kg myo-inositol diet as a control (Ctrl). The experiment was carried out in tanks (50 L) with satiety feeding, and the experiment lasted for 6 weeks. After sampling, the serum was used to measure immune function, the hepatopancreas homogenate was used to measure the antioxidant capacity and hepatopancreas damage state, the hepatopancreas was used for transcriptomics analysis, and the gills were used for qPCR to measure osmotic pressure regulation. The results showed that the final weight and survival of the shrimp in the 1020 mg/kg group increased significantly compared with those in the other low salinity groups, but the final weight and biomass increase were significantly lower than those in the Ctrl group. Dietary myo-inositol improved the antioxidant capacity of shrimp under low salinity. B-cell hyperplasia and hepatic duct damage were observed in the hepatopancreas in the 0 mg/kg group. The results of transcriptome analysis showed that myo-inositol could participate in the osmotic pressure regulation of shrimp by regulating carbohydrate metabolism, amino acid metabolism, lipid metabolism and other related genes. Myo-inositol significantly affected the expression of related genes in ion transporter and G protein-coupled receptor-mediated pathways. This study demonstrated that myo-inositol can not only act as an osmotic pressure effector and participate in the osmolar regulation of shrimp through the phosphatidylinositol signaling pathway mediated by G protein-coupled receptors but also relieve low salinity stress by mediating physiological pathways such as immunity, antioxidation, and metabolism in shrimp. The binomial regression analysis of biomass increases and survival showed that the appropriate amount of myo-inositol in the L. vannamei diet was 862.50–1275.00 mg/kg under low salinity.

Different Protein Hydrolysates Can Be Used in the Penaeus vannamei (Boone, 1934) Diet as a Partial Replacement for Fish Meal during the Grow-Out Phase

This study evaluated the inclusion of protein hydrolysates and a commercial product as a partial replacement for fish meals in the diet of Pacific white shrimp (Penaeus vannamei) during the grow-out phase. A recirculation system with 24 experimental units and a biological filter was used. The experimental design was completely randomized with six treatments: control; chicken protein hydrolysate (CPH); enzymatic hydrolysate of chicken feathers; Aquabite®; CPH + maltodextrin; CPH + yeast; and four replicates. After 50 days, the zootechnical performance and animal welfare parameters, centesimal carcass composition, digestive enzyme activity, and hemocyte count were evaluated. The treatments did not affect the zootechnical performance and total hemocyte count of the animals (p &gt; 0.05). The evaluation of the antenna length indicated that all animals were in good health. The antenna length in treatment T5 was significantly greater (p &gt; 0.05) than that in T4 and similar to that in treatments T3 and T6, demonstrating a positive influence of dietary protein hydrolysates. Concerning animal welfare, dietary protein hydrolysates influenced the length of the antenna (p &lt; 0.05). The antenna length associated with different treatments indicated that the animals were in good welfare conditions in the production environment. With respect to body chemical composition, dry matter, ether extract, and ash were affected by the treatments (p &lt; 0.05). Regarding the analysis of digestive enzymes, the treatments influenced the activities of amylase and trypsin (p &lt; 0.05). The performance of the animals was satisfactory under all treatments, including enzymatic activity, demonstrating the possibility of using hydrolysates.

Based on hydrogen and disulfide-mediated bonds, l-lysine and l-arginine enhanced the gel properties of low-salt mixed shrimp surimi (Antarctic krill and Pacific white shrimp)

This study delved into the effects of l-lysine (Lys) and l-arginine (Arg) on the gel properties and intermolecular interactions of low-salt (NaCl, 1 g/100 g) mixed shrimp surimi (Antarctic krill and Pacific white shrimp). The addition of Lys and Arg improved the gel strength and water holding capacity of low-salt gels, which were superior to the properties of STPP and high-salt (NaCl, 2.25 g/100 g) gels. These results can be attributed to the role of Lys and Arg in enhancing hydrogen and disulfide bonds within the low-salt gel system, promoting the solubilization of myofibrillar proteins (MP) and consequently increasing the number of MP molecules participating in gel formation. Antarctic krill MP did not show gel-forming ability and exerted a diluting effect on low-salt mixed shrimp surimi gels. Molecular docking analysis indicated the stable binding of Lys and Arg to myosin.

Application of Bacillus Coagulans as Paraprobiotic Against Acute Hepatopancreatic Necrosis Disease in Shrimp.

Paraprobiotics, known as non-viable or ghost probiotics, have attracted attention for their benefits over live microbial cells. This study was designed to investigate the paraprobiotic effects of heat-killed Bacillus coagulans on the white leg shrimp Litopenaeus vannamei. The paraprobiotic formulation was prepared in three different concentrations including B. coagulans 1 (107 cells g-1 diet), B. coagulans 2 (108 cells g-1 diet), and B. coagulans 3 (109 cells g-1 diet) through heat inactivation method. Preliminary toxicity assessments revealed that post-larvae shrimps (mean weight ± SE: 0.025 ± 0.007g) treated with B. coagulans 1, 2 and 3 paraprobiotic formulations exhibited no mortality, confirming the non-toxic nature of the formulated diet. In a 90-day feeding trial involving juvenile shrimps (mean weight ± SE: 0.64 ± 0.05g), growth parameters and feed conversion ratios improved in all experimental groups. Subsequently, these shrimps were challenged with Vibrio parahaemolyticus, revealing that paraprobiotic-fed shrimps exhibited significant survival rate improvements. Oxidative stress-related enzyme activities, such as superoxide dismutase and catalase, increased in paraprobiotic-fed shrimps post-Vibrio challenge, while the challenged control group showed decreased activity (p < 0.001). Nitric oxide levels are also increased in paraprobiotic-treated shrimp, with B. coagulans 3 showing a significant rise in nitric oxide activity (p < 0.001). This study further demonstrated the positive impact of paraprobiotic treatment on digestive enzymes, immune-related parameters (e.g., total hemocyte count, prophenoloxidase, and respiratory burst activity), and overall disease resistance. These findings suggest that B. coagulans paraprobiotics have the potential to enhance antioxidant, antibacterial, and immune-related responses in L. vannamei, making them a valuable addition to shrimp aquaculture.

Comparative Analysis of the Culture of Pink Shrimp Farfantepenaeus brasiliensis and Pacific White Shrimp Litopenaeus vannamei in Biofloc System

Shrimp farming in the Biofloc Technology System (BFT) is already considered an alternative to the traditional culture. The bioflocs maintain the water quality and can be used as a food supplement for shrimp. The Pacific white shrimp Litopenaeus vannamei forms the basis for most of the production in BFT. However, its culture is limited by the low temperatures. Thus, the BFT culture potential of native species, such as the pink shrimp Farfantepenaeus brasiliensis, should be considered. The present study aimed to compare the cultures of F. brasiliensis and L. vannamei in the grow-out phase in the BFT system. The experiment comprised two treatments: (FB), grown out of F. brasiliensis, and (LV), grown out of L. vannamei. The study lasted 70 days and was conducted at the Marine Station of Aquaculture at the Federal University of Rio Grande, Rio Grande do Sul State, Brazil. The stocking density was 100 shrimp/m² for both species. The shrimp were fed twice a day with commercial food. The physicochemical parameters of the water were monitored throughout the experimental period. The results showed that all physicochemical parameters of the water remained within the tolerated limits for both species. However, during the growth phase in the BFT, it was observed that the L. vannamei shrimp showed a better zootechnical performance than F. brasiliensis. The results indicate that L. vannamei has a higher capacity to catch bioflocs as supplementary food, demonstrating a better response of that species to the BFT system in the grow-out phase compared to F. brasiliensis.

Diversity of heat shock proteins in response to various stressors in the Pacific white shrimp Litopenaeus vannamei

Heat shock proteins (HSPs) serve as an evolutionarily conserved superfamily in response to various environmental stressors in almost all organisms. The Pacific white shrimp, Litopenaeus vannamei, is a worldwide aquaculture species, which have to face various environmental stressors during the whole aquaculture process. Landscapes of HSPs at genomic level will be helpful for understanding the mechanism of this species in environment adaptation. In this study, a comprehensive analysis on the composition and expression profile of HSPs have been performed in L. vannamei. A total of 76 HSP encoding genes (one LvHSP10s, four LvsHSPs, 38 LvHSP40s, ten LvHSP60s, 14 LvHSP70s, five LvHSP90s and four LvHSP100s) have been identified. Most of these genes are dispersedly distributed in the genome, except for seven pairs of tandemly duplicated genes. Multi-transcriptome analyses indicated that LvHSPs are sensitive to various stressors, including pathogen infection, salinity, ammonia or temperature stress. The LvHSP family exhibited obvious tissue specificity in response to various stressors. Additionally, we found that both tandem duplication and alternative splicing of LvHSPs contributed to the adaptation to various stresses. These findings will provide clues for stress adaptation and development of aquaculture management strategies in penaeid shrimp.

Structure and function analyses of the SRC gene in Pacific white shrimp Litopenaeus vannamei

SRC gene encodes scavenger receptor class C, a member of the scavenger receptor family, and has only been identified and investigated in invertebrates. Our previous studies have revealed that SRC is a novel candidate gene associated with body weight in Pacific white shrimp (Litopenaeus vannamei). In order to comprehend the underlying mechanism by which LvSRC affects shrimp growth, we analyzed the structure, phylogeny, expression profiles and RNA interference (RNAi) of this gene in L. vannamei. We found that LvSRC contains two CCP domains and one MAM domain, with the highest expression level in the heart and relatively low expression level in other tissues. Notably, LvSRC exhibited significantly higher expression levels in the fast-growing group among groups with different growth rates, suggesting its potential involvement as a gene contributing to the growth of L. vannamei. RNAi of LvSRC inhibited body length and body weight gain compared to the control groups. Moreover, through RNA-seq analysis, we identified 598 differentially expressed genes (DEGs), including genes associated with growth, immunity, protein processing and modification, signal transduction, lipid synthesis and metabolism. Furthermore, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses revealed significant changes in the signaling pathways related to growth, lipid metabolism and immune response, suggesting that LvSRC exhibits the potential to participate in diverse physiological processes and immune regulation. These findings deepen our understanding of the structure and function of the SRC in shrimp and lay the foundation for further research into the regulatory mechanism of LvSRC. Additionally, they provide potential applications in shrimp genetics and breeding.

RNAi-mediated knockdown of the aquaporin 4 gene impairs salinity tolerance and delays the molting process in Pacific white shrimp, Litopenaeus vannamei

The objective of this study was to investigate the function of the aquaporin 4 gene (LvAQP4), which had previously been characterized in Pacific white shrimp, Litopenaeus vannamei. To achieve this, double-stranded RNA (dsRNA) targeting LvAQP4 was synthesized and injected into shrimp, resulting in a significant reduction in the expression of LvAQP4. Subsequent to the evaluation of the impact of LvAQP4 transcriptional silencing on shrimp under salinity challenges, we observed that the downregulation of LvAQP4 expression in the gills resulted in the downregulation of aquaglyceroporin (LvAQP3) and unorthodox aquaporin (LvAQP11) genes, as well as ion transporter genes, such as LvNKAα, LvNKAβ, LvCAc, and LvVHA-a. Notably, the inhibition of LvAQP4 had a significant impact on the expression patterns of these osmoregulatory genes, particularly during periods of high salinity stress. Furthermore, there was a notable increase in the mortality rate of shrimp under high-salinity stress. Moreover, the suppression of LvAQP4 through RNA interference led to a significant delay in the molting rate of shrimp. Furthermore, it resulted in an increase in the expression of LvMIH and a significant reduction in key genes involved in the ecdysone signaling pathway, including LvEcR, LvRXR, and LvE75. These findings suggest that LvAQP4 may play a regulatory role in the molting process of shrimp by modulating MIH and the ecdysone signaling pathway. Moreover, this study lays the groundwork for future investigations into the functions of aquaporins in shrimp osmoregulation and growth, contributing to an enhanced understanding of these essential regulatory mechanisms.