Resistance Of Shrimp Research Articles

Effects of Nitrite Stress on the Antioxidant, Immunity, Energy Metabolism, and Microbial Community Status in the Intestine of Litopenaeus vannamei

Nitrite is the main environmental pollutant that endangers shrimp culture. Intestinal health is essential for the disease resistance of shrimp. In this study, Litopenaeus vannamei shrimps were separately exposed to 1 and 5 mg/L of nitrite stress for 48 h, and then the variations in intestinal health were investigated from the aspects of histology, antioxidant, immunity, energy metabolism, and microbial community status. The results showed that nitrite stress damaged intestinal mucosa, and 5 mg/L of nitrite induced more obvious physiological changes than 1 mg/L. Specifically, the relative expression levels of antioxidant (ROMO1, Nrf2, SOD, GPx, and HSP70), ER stress (Bip and XBP1), immunity (proPO, Crus, ALF, and Lys), inflammation (JNK and TNF-α), and apoptosis (Casp-3 and Casp-9) genes were increased. Additionally, intestinal energy metabolism was activated by inducing glucose metabolism (HK, PK, PDH, and LDH), lipid metabolism (AMPK and FAS), tricarboxylic acid cycle (MDH, CS, IDH, SDH, and FH), and electron transfer chain (NDH, CytC, COI, CCO, and AtpH) gene transcription. Further, the homeostasis of intestinal microbiota composition was also disturbed, especially the abundance of some beneficial genera (Clostridium sensu stricto 1, Faecalibacterium, Romboutsia, and Ruminococcaceae UCG-010). These results reveal that nitrite stress could damage the intestinal health of L. vannamei by destroying mucosal integrity, inducing oxidation and ER stress, interfering with physiological homeostasis and energy metabolism, and disrupting the microbial community.

A coumarin derivative C7 exhibits antiviral activity against WSSV by reducing phosphatidylcholine content in shrimp

The white spot syndrome virus (WSSV) causes white spot disease (WSD), a severe condition in crustacean aquaculture, leading to significant economic losses. Our previous study demonstrated that C7 is an effective therapeutic agent against WSSV infection in aquaculture. It specifically blocked viral horizontal transmission and reduced shrimp mortality in a dose- and time-dependent manner. Here, we report the potential antiviral mechanism of C7 in shrimp. C7 regulated abnormal glycerophospholipid metabolism caused by WSSV and inhibited phosphatidylcholine (PC) synthesis by more than twofold, potentially enhancing shrimp resistance to viral infection. As the primary phospholipid in the cell membrane, PC is one of the main reactants in lipid peroxidation. Our results indicated that C7 significantly reduced the levels of lipid peroxidation products 4-hydroxynonenal (4-HNE) and malondialdehyde (MDA) induced by WSSV, whereas PC had the opposite effect. Accumulation of lipid peroxidation products inhibits stimulator of interferon genes (STING) signaling. Further evidence showed that C7 promoted STING transport from the endoplasmic reticulum to the Golgi apparatus, significantly activating the expression of the shrimp interferon analogue Vago4 gene. In contrast, PC suppressed Vago4 expression. Our results demonstrated that C7 inhibited PC synthesis, reduced the degree of lipid peroxidation, promoted STING translocation, activated Vago4 expression, and ultimately exerted antiviral effects. Therefore, C7 exhibits immunoregulatory activity as a preventative agent for enhancing the innate immunity of shrimp, making it potentially useful for future immunomodulatory approaches.

Soluble trehalase responds to heavy metal stimulation by regulating apoptosis in Neocaridina denticulata sinensis

Trehalase plays an important role in insect metabolism and development by hydrolyzing blood sugar trehalose, but it seems to perform primarily an immunomodulatory function in crustaceans whose blood sugar is glucose. Metal ions as pollutants seriously affecting crustacean health, but studies on trehalase in metal immunity are still limited. In this study, a soluble trehalase (NdTre1) that could bind to multiple metals was identified from Neocaridina denticulata sinensis for investigating metal resistance. Expression profiling revealed that NdTre1 was mainly expressed in the gill and was significantly decreased following stimulation with copper (Cu²⁺) and cadmium (Cd²⁺). Transcriptomic analysis of gills revealed an increase in ecdysone synthesis after interference with NdTre1. Increased ecdysone activated the endogenous mitochondrial pathway and the mitogen activated protein kinase (MAPK) pathway to further induced apoptosis. In vitro, Escherichia coli overexpressing recombinant NdTre1 had higher survival and faster growth rates to better adapted the metal-containing medium. Overall, NdTre1 exercises an important immune function in shrimp resistance to metal stimulation by regulating apoptosis and molting. Further investigation can further explore specific response mechanisms of NdTre1 to multiple metals.

Transcriptomic analysis provides insights into the mechanisms underlying the resistance of Penaeus vannamei to Enterocytozoon hepatopenaei (EHP)

The Penaeus vannamei aquaculture industry is facing a significant challenge in the form of hepatopancreatic microsporidiosis (HPM) caused by Enterocytozoon hepatopenaei (EHP), resulting in substantial economic losses. However, the extent of knowledge regarding the mechanisms by which shrimp resist EHP is limited. We screened resistant and susceptible shrimp and found that resistant shrimp had lower EHP load and less tissue damage. To gain insight into the molecular mechanisms underlying the EHP resistance of shrimp, a comparison was conducted at the transcriptional level between the resistant and susceptible families. Transcriptomic analysis of shrimp hepatopancreas revealed significant differences between the resistant and susceptible families. Compared to the susceptible family, the immune system of the resistant family was activated. The resistant family showed up-regulation in the expression of cathepsin L, C-type lectin, penaeidin, chitinase genes, and metabolism of xenobiotics by cytochrome P450-related genes. Additionally, the resistant shrimp exhibited a higher capacity for amino acid uptake. The observed differences in the resistant and susceptible family transcriptome may contribute to the shrimp's resistance to EHP.

Febrile Temperature Acts through HSP70-Toll4 Signaling to Improve Shrimp Resistance to White Spot Syndrome Virus.

In aquatic ectotherms, temperature plays a pivotal role in biological processes and the prevalence of viral diseases; however, the molecular mechanisms underlying these effects are not fully elucidated. In this study, we investigate the impact of elevated temperatures (32°C) on the immune response against white spot syndrome virus (WSSV) in shrimp (Litopenaeus vannamei). Our findings reveal that higher water temperatures, specifically 32°C, significantly inhibit WSSV replication and pathogenicity, thereby enhancing the survival rates of infected shrimp. Through transcriptome analysis and invivo experiments, we identified heat shock protein 70 (HSP70) as a key factor in this thermal regulation of immunity. Shrimp maintained at 32°C, with silenced HSP70 expression, exhibited increased viral loads and reduced survival, underscoring the crucial protective role of HSP70 against WSSV at elevated temperatures. Our results further uncover the HSP70-Toll4-Dorsal-antimicrobial peptide (AMP) pathway as a key mediator of WSSV resistance at elevated temperatures. This pathway involves the interaction of HSP70 with the Toll4 receptor, resulting in the phosphorylation of Dorsal and the consequent modulation of expression of AMPs such as the anti-LPS factor (ALF) and lysozyme (LYZ) families. Taken together, these findings advance our understanding of temperature's role in disease dynamics in aquatic ectotherms, especially the unexpected roles of HSP70 in shrimp in facilitating the innate immune system's response to thermal stress, and suggest new approaches to managing WSSV in shrimp farming, such as environmental temperature control or HSP70 induction.

Effect of taurine on growth and immune response of Pacific white shrimp (Litopenaeus vannamei) cultured at different temperatures

Low temperature is a common challenge in the culture of Pacific white shrimp (Litopenaeus vannamei), and taurine is a potential nutrient that may improve its cold-resistance. This experiment aimed to investigate effects of dietary taurine on growth and immune response of Pacific white shrimp cultured at normal and cold temperatures. Six diets were supplemented with increasing levels of taurine (0, 0.2, 0.4, 0.6, 0.8 and 1.0%) and fed to shrimp (1.59 ± 0.03 g) reared at two water temperatures (28 °C and 20 °C) for 8 weeks. The results showed that compared with 28 °C, shrimp reared at 20 °C showed lower growth performance, feed utilization, apparent digestibility and total hemocyte count (THC) (P < 0.05), but higher content of serum glucose, intracellular reactive oxygen species (ROS) and Ca2+, malonaldehyde (MDA) and apoptosis rate (P < 0.05), indicating a higher risk of oxidative damage during low temperature stress. Interestingly, shrimp could cope with cold stress by changing hemocyte composition, increasing antioxidant enzyme activity and genes expression of apoptosis and autophagy. The effect of taurine was different at different temperatures. At 28 °C, taurine supplementation improved growth rate of shrimp by increasing digestive enzyme activities, digestion absorption rate and nutrient utilization. Based on the quadratic model of weight gain rate, feed efficiency, protein retention efficiency and the broken line model of apparent digestibility coefficients of protein, the amount of taurine required for shrimp reared at 28 °C was 0.57–0.60% of dry diet. At 20 °C, taurine increased the number of THC, granulocytes, semi-granulocytes, the activities of antioxidant enzymes such as superoxide dismutase and catalase, and decreased the content of ROS in the cells, which may enhance cold resistance of shrimp. Moreover, taurine supplementation down-regulated mRNA expression of cell apoptosis genes (cyt-c, caspase-9 and caspase-3) and up-regulated mRNA expression of cell autophagy genes (atg1, atg13, atg7 and lc3) (P < 0.05), which may help to maintain cell stability at 20 °C. The optimal requirement of taurine in shrimp reared at 20 °C was 0.56–0.66% of dry diet in this experiment based on THC and MDA content. In conclusion, our study suggests that appropriate taurine promotes growth and feed utilization at optimal temperature and enhances the stability of hemocyte at low temperature in white shrimp.

Transcriptome and metabolome for identifying key metabolites impacting the Vibrio parahaemolyticus in Litopenaeus vannamei

IntroductionShrimp is an important aquaculture species worldwide. Vibrio parahaemolyticus (VP) is an opportunistic pathogen of Litopenaeus vannamei that can cause diseases such as acute hepatopancreatic necrotic disease (AHPND), resulting in significant losses to the shrimp farming industry.MethodsIn this study, We analyzed two shrimp populations by transcriptomics and non-targeted metabolomics, which exhibited significant differences in resistance to VP. Through integrated analysis, we identified genes and metabolites linked to the development of shrimp's resistance to VP.Results and discussionThe analysis revealed that the differential metabolism of flavonoid compounds, especially quercetin, significantly influences the expression of shrimp's resistance to VP. Supplementing feed with an appropriate quantity of quercetin has the potential to increase the expression of crucial genes in the NF-κB pathway, including TLR and AP1, along with the expression of the antibacterial peptide crustin, resulting in a decreased mortality rate. Together, these results indicate that an appropriate amount of quercetin can strengthen the immune response of shrimp to VP, thereby reducing the incidence of AHPND.

Effect of soybean meal replacement with corn gluten meal on the survival, biochemical and metabolic responses, and disease resistance of Pacific white shrimp (Litopenaeus vannamei)

Abstract This study delves into the potential of replacing soybean meal (SBM) with corn gluten meal (CGM) in the diet of Litopaeneaus vannamei. We aimed to investigate the effects of a dietary soybean meal replacement on various aspects of shrimp, including survival, biochemical indices, digestive enzymes, metabolomics, and disease resistance against Vibrio harveyi. To conduct the study, we fed 840 juvenile Pacific shrimp seven different diets, each containing varying levels of CGM. The control group received a diet with 0% CGM; the other diets contained 3%, 5%, 7%, 9%, 12%, and 14% CGM. Each group comprised three replicates, and the shrimp were fed their diets for eight weeks. Our findings revealed that the survival rate of the shrimp ranged from 90.83% to 97.50% and did not differ significantly between the control and those fed diet treatments 2–5. Additionally, there were no significant differences in crude protein, moisture, and lipid content. However, we observed that total antioxidant capacity content increased with the dietary inclusion of CGM. Furthermore, malondialdehyde content decreased with increasing CGM levels, while superoxide dismutase increased, indicating no obvious oxidative damage was observed in CGM treatment groups. Interestingly, shrimp fed diets 2 and 3 had considerably lower alanine aminotransferase activity than shrimp in the control group. The disease resistance in shrimp was improved across all treatment groups, with a notably higher CGM inclusion having the highest level of mortality during the challenge test. Finally, we analyzed the metabolomics data and found PCA score plots clearly separated the control group and shrimp fed CGM diets. Our study revealed that a 3% substitution rate of SBM with CGM can enhance survival and immunity, regulate metabolites and improve disease resistance.

Responses of growth performance, immunity, disease resistance of shrimp and microbiota in Penaeus vannamei culture system to Bacillus subtilis BSXE-1601 administration: Dietary supplementation versus water addition

This study evaluated the effects of Bacillus subtilis BSXE-1601, applied either as dietary supplementation or water addition, on growth performance, immune responses, disease resistance of Penaeus vannamei, and microbiota in shrimp gut and rearing water. During the 42-day feeding experiment, shrimp were fed with basal diet (CO and BW group), basal diet supplemented with live strain BSXE-1601 at the dose of 1 × 109 CFU kg−1 feed (BD group) and 15 mg kg−1 florfenicol (FL group), and basal diet with strain BSXE-1601 added to water at the concentration of 1 × 107 CFU L−1 every five days (BW group). Results showed that dietary supplementation of strain BSXE-1601 significantly promoted growth performance of shrimp, both in the diet and water, enhanced disease resistance against Vibrio parahaemolyticus (P < 0.05). The BD and BW groups exhibited significant increases in acid phosphatase, alkaline phosphatase, lysozyme, peroxidase, superoxide dismutase activities, phenonoloxidase content in the serum of shrimp compared to the control (P < 0.05). Meanwhile, the expression of immune-related genes proPO, LZM, SOD, LGBP, HSP70, Imd, Toll, Relish, TOR, 4E-BP, eIF4E1α, eIF4E2 were significantly up-regulated compared to the control (P < 0.05). When added in rearing water, strain BSXE-1601 induced greater immune responses in shrimp than the dietary supplement (P < 0.05). Chao1 and Shannon indices of microbiota in rearing water were significantly lower in BD group than in the control. The microbiota in rearing water were significantly altered in BD, BW and FL groups compared to the control, while no significant impacts were observed on the microbiota of shrimp gut. When supplemented into the feed, strain BSXE-1601 obviously reduced the number of nodes, edges, modules in the ecological network of rearing water. The results suggested that dietary supplementation of BSXE-1601 could be more suitable than water addition in the practice of shrimp rearing when growth performance, non-specific immunity, disease resistance against V. parahaemolyticus in shrimp were collectively considered.

Strain-specific responses of Penaeus vannamei to two Enterococcus faecium strains supplementation: A trade-off between growth and immunity

Probiotic properties are highly species- or even strain- specific. Strain-specific responses of growth performance, non-specific immunity, disease resistance, and intestinal microbiota in Penaeus vannamei to two Enterococcus faecium strains supplementation were investigated in this study. Basal diet (control, CON) was supplemented with E. faecium HK and LYB at the dose of 1 × 1010 CFU / kg (HK group) and 1 × 1011 CFU / kg (LYB group), respectively. The results indicated that the HK and LYB groups exhibited significant enhancements in growth performance, non-specific immunity, and disease resistance of shrimp against Vibrio parahaemolyticus compared to the control (P < 0.05). However, the specific growth rate of shrimp in the LYB group was significantly better than that in the HK group (P < 0.05). Furthermore, the HK group showed significant increases in phenoloxidase, total nitric oxide synthase activities, lysozyme content in the serum, as well as the relative expression levels of proPO, LGBP, Imd, Relish, and eIF4E2 genes in the hepatopancreas compared to the LYB group (P < 0.05). These results suggested the strain HK exhibited better non-specific immunity efficiency while the strain LYB exerted better growth enhancement in shrimp. Dietary both of strain HK and LYB significantly altered microbial community structure (P < 0.05), and the strain HK significantly improved intestinal microbial diversity in shrimp. The relative abundance of Rubritaleaceae and Rhodobacteraceae were significantly increased, whereas those of facultative anaerobes and potential pathogens (i.e., Vibrionaceae, Flavobacteriaceae and Erysipelotrichaceae, etc.) were reduced in response to dietary supplementation of E. faecium HK and LYB. Furthermore, dietary both of strain HK and LYB could promote intestinal microbial community stability by increasing average connectivity, cooperation interactions, the number of generalists within the network. When growth performance and intestinal microbial homeostasis of shrimp are considered, E. faecium LYB might be better than the strain HK in shrimp farming.

Characterization and function analysis of cathepsin C in Marsupenaeusjaponicus

Cathepsin C is a cysteine protease widely found in invertebrates and vertebrates, and has the important physiological role participating in proteolysis in vivo and activating various functional proteases in immune/inflammatory cells in the animals. In order to study the role of cathepsin C in the disease resistance of shrimp, we cloned cathepsin C gene (MjcathC) from Marsupenaeus japonicus, analyzed its expression patterns in various tissues, performed MjcathC-knockdown, and finally challenged experimental shrimps with Vibrio alginolyticus and WSSV. The results have shown the full length of MjcathC is 1782 bp, containing an open reading frame of 1350 bp encoding 449 amino acids. Homology analysis revealed that the predicted amino acid sequence of MjcathC shared respectively 88.42 %, 87.36 % and 87.58 % similarity with Penaeus monodon, Fenneropenaeus penicillatus and Litopenaeus vannamei. The expression levels of MjcathC in various tissues of healthy M. japonicus are the highest in the liver, followed by the gills and heart, and the lowest in the stomach. The expression levels of MjcathC were significantly up-regulated in all examined tissues of shrimp challenged with WSSV or V. alginolyticus. After knockdown-MjcathC using RNAi technology in M. japonicus, the expression levels of lectin and heat shock protein 70 in MjcathC-knockdown shrimp were significantly down-regulated, and the mortality of MjcathC-knockdown shrimp challenged by WSSV and V. alginolyticus significantly increased. Knockdown of the MjcathC reduced the resistance of M. japonicus to WSSV and V. alginolyticus. The above results have indicated that cathepsin C may play an important role in the antibacterial and antiviral innate immunity of M. japonicus.

Evaluation of Recombinant Viral Inhibitor Protein for Whiteleg Shrimp Resistance Against White Spot Syndrome Virus

Viral inhibitor protein (VIP) contributes to shrimp resistance against virus infection. VIP can be used as a new strategy to control white spot syndrome virus (WSSV) infection in shrimp culture by inhibiting its action. This study aimed to evaluate the application of VIP on the whiteleg shrimp (Litopenaeus vannamei) to inhibit the WSSV infection. Shrimp at an average body weight of 6.66±0.08 g was injected by recombinant VIP with two different concentrations (1 μg/g and 10 μg/g) and challenged with WSSV. As a positive control was the shrimp not injected with recombinant VIP and challenged with WSSV, and as a negative control was the shrimp not injected with recombinant VIP and not challenged with WSSV. The results showed that the survival rate of shrimp that were injected with recombinant VIP was significantly increased after being challenged with WSSV (P&lt;0.05). The survival and immune response of shrimp that were injected with recombinant VIP were higher than the positive controls (P&lt;0.05). In this study, the application of recombinant VIP can significantly increase the shrimp resistance against WSSV up to 95.65% higher than the positive control.

The synergistic Lactobacillus plantarum L20 and Sargassum polycystum -added diet for improvement of Black tiger shrimp, Penaeus monodon ‘s growth, immune responses, bacterial profiles, and resistance against Vibrio parahaemolyticus associated Acute hepatopancreatic necrosis disease (AHPND) infection

Acute hepatopancreatic necrosis disease (AHPND) has inflicted massive economic losses and posed a considerable threat to the development of penaeid shrimp aquaculture in Malaysia. The restriction on antibiotic uses have necessitated exploring alternatives preventive measures against AHPND outbreak, such as the use beneficial bacteria and nutritional additives. In this study, diets which were fed to Penaeus monodon postlarvae (PL15) were fed with diets containing probiotic (L. plantarum at 108 CFU/mL), prebiotic (S. polycystum at 2%) and synbiotic diets (combination of probiotic and prebiotic) formulations. These diets were administered in triplicate for 35 days, followed by an immersion challenge with 6 × 105 CFU/mL AHPND-causing V. parahaemolyticus S2–4. Sampling of shrimp’s cephalothorax and abdomen from the feeding trial and the immersion challenge were conducted for gene expression and histopathology analyses. Results indicated that the synbiotic-fed group displayed the most significant weight gain, specific growth rate, and protein conversion ratio among the tested groups. In addition, shrimp cephalothorax from this group displayed a significant immune response, with expression of LGBP, peroxinectin, prophenoloxidase during post-feeding trial, and expression of prophenoloxidase, toll-like receptor, penaeidin, during post-challenge trial. Furthermore, the highest L. plantarum concentration in abdomen, lowest V. parahaemolyticus S2–4 concentration in cephalothorax and highest percent survival of shrimp during post-challenge were observed in this group. Therefore, this study highlighted the positive effect of synbiotic-supplemented diet on growth, immune response, and disease resistance of shrimp, offering a promising and sustainable solution to alleviate substantial production losses in shrimp farming.

Comparative transcriptome analysis of hepatopancreas reveals the potential mechanism of shrimp resistant to Vibrio parahaemolyticus infection

Vibrio parahaemolyticus carrying a pathogenic plasmid (VPAHPND) is one of the main causative agents of acute hepatopancreatic necrosis disease (AHPND) in shrimp aquaculture. Knowledge about the mechanism of shrimp resistant to VPAHPND is very helpful for developing efficient strategy for breeding AHPND resistant shrimp. In order to learn the mechanism of shrimp resistant to AHPND, comparative transcriptome was applied to analyze the different expressions of genes in the hepatopancreas of shrimp from different families with different resistance to VPAHPND. Through comparative analysis on the hepatopancreas of shrimp from VPAHPND resistant family and susceptible family, we found that differentially expressed genes (DEGs) were mainly involved in immune and metabolic processes. Most of the immune-related genes among DEGs were highly expressed in the hepatopancreas of shrimp from resistant family, involved in recognition of pathogen-associated molecular patterns, phagocytosis and elimination of pathogens, maintenance of reactive oxygen species homeostasis and other immune processes etc. However, most metabolic-related genes were highly expressed in the hepatopancreas of shrimp from susceptible family, involved in metabolism of lipid, vitamin, cofactors, glucose, carbohydrate and serine. Interestingly, when we analyzed the expression of above DEGs in the shrimp after VPAHPND infection, we found that the most of identified immune-related genes remained at high expression levels in the hepatopancreas of shrimp from the VPAHPND resistant family, and most of the identified metabolic-related genes were still at high expression levels in the hepatopancreas of shrimp from the VPAHPND susceptible family. The data suggested that the differential expression of these immune-related and metabolic-related genes in hepatopancreas might contribute to the resistance variations of shrimp to VPAHPND. These results provided valuable information for understanding the resistant mechanism of shrimp to VPAHPND.

Metabolomic responses based on transcriptome of the hepatopancreas in Exopalaemon carinicauda under carbonate alkalinity stress

High carbonate alkalinity is one of the major stress factors for survival of aquatic animals in saline-alkaline water. Exopalaemon carinicauda is a good model for studying the saline-alkaline adaption mechanism in crustacean because of its great adaptive capacity to alkalinity stress. In this study, non-targeted liquid chromatography-mass spectrometry (LC-MS) metabolomics analyses based on high-throughput RNA sequencing (RNA-Seq) were used to study the metabolomic responses of hepatopancreas in E. carinicauda at 12 h and 36 h after acute carbonate alkalinity stress. The results revealed that most of the significantly differential metabolites were related to the lipid metabolism. In particular, the sphingolipid metabolism was observed at 12 h, the glycerophospholipid metabolism was detected at 36 h, and the linoleic acid metabolic pathway was significantly enriched at both 12 h and 36 h. The combined transcriptome and metabolome analysis showed that energy consumption increased at 12 h, resulting in significant enrichment of AMPK signaling pathways, which contributed to maintain energy homeostasis. Subsequently, the hepatopancreas provided sufficient energy supply through cAMP signaling pathway and glycerophosphate metabolism to maintain normal metabolic function at 36 h. These findings might help to understand the molecular mechanisms of the E. carinicauda under carbonate alkalinity stress, thereby promote the research and development of saline-alkaline resistant shrimp.

Specific gut bacterial taxa inhabited in healthy shrimp (Penaeus vannamei) confer protection against Vibrio parahaemolyticus challenge

Host gut bacterial community has strong resistance to the invasion of pathogens. However, the specific gut taxa that could confer the resistance against pathogens in shrimp are largely unknown. Here, we demonstrated that the shrimp in the same tank showed different resistance after pathogenic Vibrio parahaemolyticus challenge. Subsequently, the gut bacterial communities of healthy, diseased, and moribund shrimp were analyzed. The results indicated that the gut bacterial community in the healthy shrimp still kept a high stability after challenge, while they were gradually disordered with the severity of disease in the diseased, and moribund shrimp. Certain specific taxa belonging to Rhodobacteraceae (e.g., Ruegeria, Paracoccus, Sulfitobacter, and Phaeobacter), Flavobacteriaceae (e.g., Tenacibaculum) and Demequinaceae (e.g., Demequina) were mainly depleted in the moribund shrimp, compared to that in healthy, and diseased shrimp. Seven corresponding strains of above specific taxa including five Rhodobacteraceae, one Tenacibaculum and one Demequina were isolated from the shrimp gut. Then, four different synthetic communities (SynComs) were constructed by using these isolates: SynComA, all five strains from Rhodobacteraceae; SynComB, SynComA + T. lutimaris HBG23; SynComC, SynComA + D. globuliformis TCG4; and SynComD, SynComA + T. lutimaris HBG23 + D. globuliformis TCG4. The addition of these SynComs could not only improve the fitness of shrimp, but also protect them against subsequent V. parahaemolyticus challenge, especially the addition of SynComD. Our study revealed that specific gut bacteria inhabited in healthy shrimp could improve shrimp resistance against pathogenic microbes.

THE PERFORMANCE OF PACIFIC WHITE SHRIMP INFECTED BY Vibrio harveyi AFTER MANGROVE LEAF EXTRACT SUPPLEMENTATION

&lt;p&gt;This research investigated the advantages and determined the optimal dosage of mangrove leaf supplementation to enhance growth and disease resistance in shrimp. PL-20 Pacific White Shrimp were given different doses of mangrove leaf extract added to their feed: 0 ppm/500 g (A), 225 ppm/500 g (B), 250 ppm/500 g (C), and 275 ppm/ 500 g (D), over a 30-day period. This experimental research was conducted using a completely randomized design with four treatments and three replications each. Several parameters were observed: growth, feed conversion ratio (FCR), energy protein productivity (EPP), and subsequent exposure to &lt;em&gt;Vibrio harveyi &lt;/em&gt;to assess survival rate (SR). The obtained data underwent ANOVA analysis, which results demonstrated significant influence in shrimp growth, with the most notable improvement observed in treatment D. Treatment D also exhibited the highest SR value following the challenge test. Throughout the study, water quality parameters remained within the suitable range for fostering shrimp growth&lt;/p&gt;

Epigenetic Modulations for Prevention of Infectious Diseases in Shrimp Aquaculture.

Aquaculture assumes a pivotal role in meeting the escalating global food demand, and shrimp farming, in particular, holds a significant role in the global economy and food security, providing a rich source of nutrients for human consumption. Nonetheless, the industry faces formidable challenges, primarily attributed to disease outbreaks and the diminishing efficacy of conventional disease management approaches, such as antibiotic usage. Consequently, there is an urgent imperative to explore alternative strategies to ensure the sustainability of the industry. In this context, the field of epigenetics emerges as a promising avenue for combating infectious diseases in shrimp aquaculture. Epigenetic modulations entail chemical alterations in DNA and proteins, orchestrating gene expression patterns without modifying the underlying DNA sequence through DNA methylation, histone modifications, and non-coding RNA molecules. Utilizing epigenetic mechanisms presents an opportunity to enhance immune gene expression and bolster disease resistance in shrimp, thereby contributing to disease management strategies and optimizing shrimp health and productivity. Additionally, the concept of epigenetic inheritability in marine animals holds immense potential for the future of the shrimp farming industry. To this end, this comprehensive review thoroughly explores the dynamics of epigenetic modulations in shrimp aquaculture, with a particular emphasis on its pivotal role in disease management. It conveys the significance of harnessing advantageous epigenetic changes to ensure the long-term viability of shrimp farming while deliberating on the potential consequences of these interventions. Overall, this appraisal highlights the promising trajectory of epigenetic applications, propelling the field toward strengthening sustainability in shrimp aquaculture.

Effects of dietary supplementation of Achyranthes aspera extract on growth performance, digestibility, innate immunity, antioxidant capacity, and disease resistance of juvenile Pacific white shrimp, Penaeus vannamei

AbstractA supplemental effect of Achyranthes aspera extract (200 mg/kg phytosterol) in diets was evaluated for Pacific white shrimp (Penaeus vannamei) on growth performance, digestibility, innate immunity, antioxidant capacity, and disease resistance against Vibrio parahaemolyticus. A fish meal and soybean meal‐based control diet (Con; protein 38.0% and lipid 8.7%) was formulated and five other diets were prepared by adding A. aspera extract into Con diet to be 0.05, 0.1, 0.2, 0.4, and 0.8 mg phytosterol/kg concentration (designated as P05, P10, P20, P40, and P80, respectively). Three replicate groups of 30 shrimp (initial body weight, 0.40 ± 0.001 g) per diet were randomly assigned into 18 acrylic tanks (240 L) and fed one of the diets for 53 days. The growth performance and feed utilization efficiency were significantly higher in shrimp fed P20 and P80 diets than in shrimp fed Con and P10 diets. The dietary phytosterol supplementation improved non‐specific immune response, antioxidant capacity, and apparent digestibility coefficients of dry matter and protein of shrimp. The IGF‐binding protein gene expression was also upregulated with dietary phytosterol supplementation. During the challenge test, the disease resistance of shrimp was significantly enhanced against V. parahaemolyticus when shrimp were fed P20 diet. These results indicate that A. aspera extract could be used as a functional feed additive for the improvements in the growth performance, feed efficiency, innate immunity, antioxidant capacity, digestibility, and disease resistance of the shrimp. The optimum dietary inclusion level of the phytosterol seems to be 0.2–0.4 mg/kg diet.

LysM-containing proteins function in the resistance of Litopenaeus vannamei against Vibrio parahaemolyticus infection

Lysin motif (LysM) is a functional domain that can bind to peptidoglycans, chitin and their derivatives. The LysM-containing proteins participate in multiple biological processes, such as the hydrolysis of bacterial cell walls and the perception of PAMPs in plants and high animals. In the present study, two genes encoding LysM-containing proteins, designated as LvLysM1 and LvLysM2, were identified in the Pacific white shrimp, Litopenaeus vannamei, and their functions during Vibrio infection were analyzed. The open-reading frame (ORF) of LvLysM1 was 795 bp, only encoding a LysM domain at the N-terminal region. The ORF of LvLysM2 was 834 bp, encoding a LysM domain at the central region and a transmembrane region at the C-terminal region. Both LvLysM1 and LvLysM2 were widely transcribed in all tested shrimp tissues. Enzyme-linked immunosorbent assay (ELISA) showed that the recombinant protein of LvLysM2 could bind to different bacterial polysaccharides, while LvLysM1 showed no direct binding activity. The transcripts of LvLysMs in gills increased significantly after infection with Vibrio parahaemolyticus. When LvLysM1 or LvLysM2 was knocked down by dsRNA, the mortality of shrimp was significantly increased after infection with Vibrio parahaemolyticus. Interestingly, some SNPs existed in these two genes were apparently correlated with the VpAHPND resistance of shrimp. These results suggested that LvLysM1 and LvLysM2 might contribute to the disease resistance of shrimp. The data provide new knowledge about the function of LysM-containing proteins in shrimp and potential genetic markers for disease resistance breeding.