Shrimp Penaeus Vannamei Research Articles

Peroxiredoxin 6 (Prx6) of Penaeus vannamei and effect of phenanthrene on Prx6 and glutathione peroxidase 4 expression, glutathione-dependent peroxidase activity and lipid peroxidation

Polycyclic aromatic hydrocarbons (PAHs), such as phenanthrene (PHE), are common pollutants found in coastal areas where shrimp farming is developed. Even though PAHs can have adverse effects on physiology, shrimp can detoxify and metabolize toxic compounds and neutralize the reactive oxygen species (ROS) produced during this process. This requires the activation of multiple antioxidant enzymes, including peroxiredoxin 6 (Prx6). Prx6 uses glutathione (GSH) to reduce phospholipid hydroperoxides, a function shared with GSH peroxidase 4 (GPx4). Prx6 has been scarcely studied in crustaceans exposed to pollutants. Herein, we report a novel Prx6 from the shrimp Penaeus vannamei that is abundantly expressed in gills and hepatopancreas. To elucidate the involvement of Prx6 in response to PAHs, we analyzed its expression in the hepatopancreas of shrimp sub-lethally exposed to PHE (3.3 μg/L) and acetone (control) for 24, 48, 72, and 96 h, along with GPx4 expression, GSH-dependent peroxidase activity, and lipid peroxidation (indicated by TBARS). We found that GPx4 expression is not affected by PHE, but Prx6 expression and peroxidase activity decreased during the trial. This might contribute to the rise of TBARS found at 48 h of exposure. However, maintaining GPx4 expression could aid to minimize lipid damage during longer periods of exposure to PHE.

Assessment of microplastic hazards in Penaeus vannamei shrimp in a typical estuary of China: polymer composition, risk assessment, and health implications

Assessment of microplastic hazards in Penaeus vannamei shrimp in a typical estuary of China: polymer composition, risk assessment, and health implications

The effects of Panax ginseng on growth enhancement, innate immunity, and microbiome profiling in Penaeus vannamei

BackgroundIn aquaculture, feed additives are widely explored. Among them, Panax ginseng Meyer, a natural herbal remedy, has demonstrated its efficacy in many aquaculture species. However, research regarding Penaeus vannamei shrimp, one of the most significant species in aquaculture, remains limited. MethodsThis study investigates the benefits of P. ginseng for P. vannamei, specifically its effects on growth, innate immunity, and shrimp microbiome. Juvenile P. vannamei were fed commercial feed mixed with red ginseng extract at 5 concentrations (0.00 %, 0.05 %, 0.10 %, 0.50 %, and 1.00 %) for 6 weeks. Body weight was measured on days 21 and 42. On day 42, three shrimp per group were selected for further analysis. ResultsIn the growth study, Group 0.10 % displayed significantly improved FBW, WG, SGR, and FCR compared to those in Group 0.00 % on day 42. The qPCR assay showed significantly higher IGF-BP gene expression in Groups 0.05 %, 0.10 %, and 1.00 % compared to Group 0.00 %. In the innate immunity analysis, SOD activity was significantly higher in Groups 0.05 % and 0.50 % compared to that in Group 0.00 %. In the bacterial community analysis, Group 0.10 % exhibited higher Flavobacteriaceae and lower Vibrionaceae at the family level compared to Group 0.00 %. At the genus level, Group 0.10 % showed increased unspecified Flavobacteriaceae and decreased Vibrio compared to Group 0.00 %. ConclusionAdding P. ginseng to the feed enhanced growth, immune response, and microbiome composition in P. vannamei. Further research on refining dosage levels and utilizing red ginseng residues could boost commercial productivity and economic benefits in aquaculture practices.

An enzymatic recombinase amplification assay combined with CRISPR-Cas12a for the rapid detection of acute hepatopancreatic necrosis disease in shrimp Penaeus vannamei

An enzymatic recombinase amplification assay combined with CRISPR-Cas12a for the rapid detection of acute hepatopancreatic necrosis disease in shrimp Penaeus vannamei

Draft genome sequence of Bacillus velezensis strain 3TSA-3, a potential probiotic for Pacific white shrimp Penaeus vannamei postlarvae isolated from commercial hatchery tanks.

We report the draft genome of Bacillus velezensis strain 3TSA-3, isolated from Pacific white shrimp Penaeus vannamei postlarvae collected from a hatchery tank with high survival despite the presence of pathogenic Vibrio. The strain possesses genes encoding bacteriocins and lacks virulence factor genes, characteristics for a potential aquaculture probiotic.

Improved genome assembly of the whiteleg shrimp Penaeus (Litopenaeus) vannamei using long- and short-read sequences from public databases.

The Pacific whiteleg shrimp Penaeus (Litopenaeus) vannamei is a highly relevant species for the world's aquaculture development, for which an incomplete genome is available in public databases. In this work, PacBio long-reads from 14 publicly available genomic libraries (131.2 Gb) were mined to improve the reference genome assembly. The libraries were assembled, polished using Illumina short-reads, and scaffolded with P. vannamei, Feneropenaeus chinensis, and Penaeus monodon genomes. The reference-guided assembly, organized into 44 pseudo-chromosomes and 15,682 scaffolds, showed an improvement from previous reference genomes with a genome size of 2.055 Gb, N50 of 40.14 Mb, L50 of 21, and the longest scaffold of 65.79 Mb. Most orthologous genes (92.6%) of the Arthropoda_odb10 database were detected as "complete," and BRAKER predicted 21,816 gene models; from these, we detected 1,814 single-copy orthologues conserved across the genomic references for Marsupenaeus japonicus, F. chinensis, and P. monodon. Transcriptomic-assembly data aligned in more than 99% to the new reference-guided assembly. The collinearity analysis of the assembled pseudo-chromosomes against the P. vannamei and P. monodon reference genomes showed high conservation in different sets of pseudo-chromosomes. In addition, more than 21,000 publicly available genetic marker sequences were mapped to single-site positions. This new assembly represents a step forward to previously reported P. vannamei assemblies. It will be helpful as a reference genome for future studies on the evolutionary history of the species, the genetic architecture of physiological and sex-determination traits, and the analysis of the changes in genetic diversity and composition of cultivated stocks.

White spot syndrome virus endogenous viral elements (EVE) revealed by circular viral copy DNA (cvcDNA) in shrimp

Circular, viral copy DNA (cvcDNA) can reveal the existence of endogenous viral elements (EVE) in shrimp genomic DNA. Here we describe isolation and sequencing of cvcDNA from a breeding stock of the whiteleg shrimp Penaeus vannamei. The stock was developed by onward breeding and selection for white spot syndrome virus (WSSV)-free individual survivors of white spot disease outbreaks. The stock exhibits high tolerance to WSSV. A pool of DNA extracted from 10 shrimp from this stock was subjected to cvcDNA isolation and amplification followed by high throughput sequencing. This revealed DNA fragments corresponding to locations covering much of the 300,000 bp WSSV genome. However, high frequency-read-fragments (HFRF) mapped to a surprisingly small region of approximately 1400 bp. We hypothesized that the HFRF reflected their selection due to provision of tolerance to WSSV. Four PCR primer sets were designed to cover the 1365 bp mapped region. One pair (Set 1) targeted the whole 1365 bp mapped region, while another 3 primer sets (Set 2–4), targeted regions within the 1365 bp target. All 4 primer sets were used with DNA samples from each of 36 shrimp from the same breeding stock (including the 10 used for cvcDNA preparation). Individual positive PCR results varied from shrimp to shrimp, ranging from only 1 primer set up to 4 primer sets. Only 1 specimen gave an amplicon of 1365 bp, while others gave single to multiple positive amplicons in both continuous and discontinuous regions. This indicated that the amplicons did not arise from contiguous targets and might vary in insertion length. The results also confirmed that none of the shrimp were infected with WSSV. Sequencing of the PCR amplicons of expected sizes revealed sequence identity to extant WSSV genomes. This data will be used to screen the breeding stock for EVE that provide WSSV tolerance.

A Comparison of Resources Usage for Two White-Leg Shrimp (Penaeus vannamei) Farming Systems (Earthen Pond System and Round Tank System)

Shrimp farming plays an important role in providing nutritious food and generating livelihoods for many millions of people worldwide. Asia is the biggest producer of shrimp contributing nearly 80% of the global shrimp aquaculture production. Black tiger shrimp (Penaeus monodon) is the main brackish water aquaculture species in Sri Lanka before 2018. White-leg shrimp (Penaeus vannamei) was a new species that was introduced in 2018 expecting a rapid increase in production in the country. Shrimp farming is classified into several categories: extensive, semi-intensive, intensive, and super-intensive based on the intensity of management practices such as stocking density, supply of feed and fertilizer, and management of water qualities. The round tank system is round-shaped and is a type of lined pond that uses an impermeable geomembrane for the retention of water. It belongs to the super-intensive category. The earthen pond is a water body that is basically enclosed by the earth. It belongs to the intensive category. The purpose of this study was to assess the amounts of land, water, and energy required per ton of harvested shrimp in two different production systems and identify the most sustainable system that is used minimum natural resources. The round tank system is located in the Erukkalampiddy area in the Mannar district, Sri Lanka. The earthen pond system is located in the Maikkulama area in the Puttalam district, Sri Lanka. Data on water usage, electricity usage, land area usage, and weight of harvested shrimp were collected during two cycles of production from August 2021 to May 2022. The t-tests were performed to compare resource usages. Land usage of the earthen pond system (950.00 m2/t shrimp, 1266.67 m2/t shrimp) is significantly greater than the round tank system (190.77 m2/t shrimp, 139.33 m2/t shrimp). Water usage of the earthen pond system (950.00 m3/t shrimp, 1266.67 m3/t shrimp) is significantly greater than the round tank system (190.77 m3/t shrimp, 139.33 m3/t shrimp). Energy usage of the round tank system (473.84 kWh/t shrimp, 591.46 kWh/t shrimp) is significantly greater than the earthen pond system (119.91 kWh/t shrimp, 154.78 kWh/t shrimp). It concludes that less land and water resources and high energy usage are required for a round tank system compared to an earthen pond system. Although establishing a round tank system will need more capital, compared to that of an earthen pond system, it is evident that the round tanksystem is more environmentally sustainable. 
 Keywords: Shrimp farming, Round tank system, Earthen pond system, White-leg shrimp (Penaeus vannamei)

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 > 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 > 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 < 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 < 0.05). Regarding the analysis of digestive enzymes, the treatments influenced the activities of amylase and trypsin (p < 0.05). The performance of the animals was satisfactory under all treatments, including enzymatic activity, demonstrating the possibility of using hydrolysates.

Integrated characterizations of intestinal bacteria and transcriptomics revealed the acute stress response to carbonate alkalinity in white shrimp Penaeusvannamei

The impact of carbonate alkalinity in saline-alkaline water on aquatic organisms, particularly Penaeus vannamei, a significant species in aquaculture, remains a critical area of study. To elucidate the acute response mechanisms of P. vannamei to elevated carbonate alkalinity environments, we utilized 16S rRNA gene and transcriptome sequencing technologies to analyze intestinal bacteria and gene expressions within various tissues. Our investigation revealed notable changes in specific intestinal bacterial OTUs, whose abundances varied preceding the overall bacterial community, indicating the sensitivity to carbonate alkalinity exposure. These shifts are accompanied by a simplification in bacterial networks and alterations in pathogenic OTUs, notably Aeromonas OTU. Concurrently, gene expression variations were observed across the hepatopancreas, gills, muscles, and intestines, with decreasing numbers of DEGs in the mentioned order. Annotation of these DEGs revealed enrichments in pathways related to transport, catabolism, immune responses, circulatory functions, and lipid metabolism. Notably, correlations between specific intestinal bacterial OTUs and gene expression shifts were identified across these tissues. Several OTUs, attributed to Rhizobiales, Saccharimonadales, Acidovora, and Aeromona, exhibited a correlation with DEGs in all four tissues, primarily associated with amino acid metabolism, signal transduction, and transport and catabolism pathways. Our study provides comprehensive insights into the dynamic responses of P. vannamei to elevated carbonate alkalinity stress. These findings contribute crucial knowledge for effective P. vannamei cultivation in saline-alkaline water, advancing our understanding in this field.

Study of microsporidians in white faecal syndrome affected farmed shrimp (Penaeus vannamei) Boone, 1931 of West Bengal, India

Enterocytozoon hepatopenaei (EHP), an intracellular microsporidian parasite, has been reported in cultivated Penaeus vannamei infected with white faecal syndrome (WFS) in south-east Asian shrimp producing countries. The appearance of white faecal strings floating on the surface of the ponds indicates a severe microsporidian infection. In the present study suspected shrimps and floating faecal strings were collected from culture ponds of study area located in Purba Medinipur district of West Bengal. This study aims to unveil the presence of microsporidians in hepatopancreas and associated histopathological changes in it using light and scanning electron microscopy, and microsporidian identification by nested PCR. Microscopic study revealed the presence of oval-shaped microsporidian spores in the hepatopancreas and nested PCR study confirmed that these spores belong to E. hepatopenaei. The spores isolated from the floating faecal strings exhibited similar morphology with those found in hepatopancreas. Histopathology of the hepatopancreas of WFS-affected shrimp exhibited alterations in hepatopancreatic tissues along with haemocytic infiltration into the inter-tubular spaces and evidence of necrosis, vacuolation and degeneration. The findings from the nested PCR analysis indicated a total of 18 positive results (69.23%) out of 26 samples studied. WFS infection can be considered a gastrointestinal disorder caused by severe EHP infection, which is significant in the grow-out ponds in the regions under study.

Effects of Cold Stress on the Hemolymph of the Pacific White Shrimp Penaeus vannamei

Temperature is an important factor in the physiological processes of aquatic organisms and can seriously affect several chemical and biological processes in their bodies, including respiratory metabolism, antioxidant capacity, immune capacity, and signal transduction. In this study, physiological, transcriptomic, and metabolomic analyses were used to investigate the response of Penaeus vannamei to cold stress. The results indicated that cold stress disrupted nucleotide metabolism and inhibited gluconeogenesis. However, shrimp exhibited response mechanisms in order to enhance cold tolerance, regulating changes in key genes and metabolites in amino acid and lipid metabolism to increase energy supply and protect cell membrane stability. In addition, the response included regulating Ca2+ pumps and ion channels to maintain intracellular ion homeostasis and osmotic balance. When the temperature dropped further, oxidative damage occurred due to overwhelming of the antioxidant defense system, and immune function was inhibited. This research provides some references regarding the molecular mechanisms involved in responding to cold stress and potential strategies to improve cold tolerance in P. vannamei; these are important references for studying the cold stress response of shrimp.

Evaluation of the osmoregulatory capacity and three stress biomarkers in white shrimp Penaeus vannamei exposed to different temperature and salinity conditions: Na+/K+ ATPase, Heat Shock Proteins (HSP), and Crustacean Hyperglycemic Hormones (CHHs)

Salinity and temperature influence growth, survival, and reproduction of crustacean species such as Penaeus vannamei where Na +/K+-ATPase plays a key role in maintaining osmotic homeostasis in different salinity conditions. This ability is suggested to be mediated by other proteins including neuropeptides such as the crustacean hyperglycemic hormones (CHHs), and heat shock proteins (HSPs). The mRNA expression of Na+/K+-ATPase, HSP60, HSP70, CHH-A, and CHH-B1, was analyzed by qPCR in shrimp acclimated to different salinities (10, 26, and 40 PSU) and temperature conditions (20, 23, 26, 29, and 32 °C) to evaluate their uses as molecular stress biomarkers. The results showed that the hemolymph osmoregulatory capacity in shrimp changed with exposure to the different salinities. From 26 to 32 °C the Na+/K+-ATPase expression increased significantly at 10 PSU relative to shrimp acclimated at 26 PSU and at 20 °C increased at similar values independently of salinity. The highest HSP expression levels were obtained by HSP70 at 20 °C, suggesting a role in protecting proteins such as Na+/K+ -ATPase under low-temperature and salinity conditions. CHH-A was not expressed in the gill under any condition, but CHH-B1 showed the highest expression at the lowest temperatures and salinities, suggesting its participation in the Na+/K+-ATPase induction. Since Na+/K+-ATPase, HSPs, and CHHs seem to participate in maintaining the osmo-ionic balance and homeostasis in P. vannamei, their expression levels may be used as a stress biomarkers to monitor marine crustacean health status when acclimated in low salinity and temperature conditions.

The influence of biofloc system on Vibrio composition, the growth and the gut microvilli performance of the Pacific white shrimp Penaeus vannamei

Biofloc technology has been shown to have a positive impact on shrimp culture by controlling pathogenic Vibrio. This study aimed to analyze the effect of biofloc on the Vibrio composition in water and shrimp gut, as well as the growth performance and microvilli of Pacific white shrimp (Penaeus vannamei). Shrimp post-larvae measuring 0.66 ± 0.02 g were reared in a glass aquarium (working volume 22 L) of 6 units with a density of 150 shrimp m-3 for 28 days. The treatments included rearing in the biofloc system with C/N ratio 10, and without a biofloc system as a control. The results showed that Vibrio was highly prevalent in the control gut (4.13%) and biofloc water (3.77%), but only a few were found in the control water (0.16%) and biofloc-treated gut (0.11%). V. hepatarius (1.10%) and V. nereis (1.06%) were found to dominate the Vibrio bacterial community in the biofloc system maintenance media, while Vibrio sp. Hep-1b-8 (2.26%) and V. parahaemolyticus (0.80%) known as a pathogenic bacteria dominated the control shrimp gut. The biofloc system significantly increased the digestive enzyme activity, growth performance, and microvilli length in the shrimp gut. In conclusion, the application of a biofloc system in shrimp culture can affect the composition and abundance of bacterial communities in both the culture environment and the shrimp gut, and improve growth performance with higher digestive enzyme activity and longer microvilli in the gut.
 
 Keywords: biocontrol, biofloc, microbiota, shrimp, Vibrio
 
 ABSTRAK
 
 Teknologi bioflok menunjukkan dampak positif pada kegiatan budidaya udang vaname dengan mengendalikan bakteri patogen salah satunya Vibrio. Penelitian ini bertujuan untuk menganalisis efek bioflok terhadap komposisi Vibrio pada air dan usus udang, serta kinerja pertumbuhan dan mikrovili udang vaname (Penaeus vanamei). Udang post-larva berukuran 0.66 ± 0.02 g dipelihara pada akuarium kaca (volume air 22 L) sebanyak 6 unit dengan kepadatan 150 ekor m-3 selama 28 hari. Perlakuan meliputi pemeliharaan udang pada sistem bioflok dengan rasio C/N 10, dan tanpa sistem bioflok sebagai perlakuan kontrol. Hasil pengamatan menunjukkan kelimpahan Vibrio yang cukup tinggi pada usus perlakuan kontrol (4.13%) dan air perlakuan bioflok (3.77%), tetapi sangat sedikit ditemukan pada air perlakuan kontrol dan usus perlakuan bioflok. Selanjutnya, V. hepatarius (2.26%) dan V. nereis (1.06%) terdeteksi mendominasi komunitas bakteri Vibrio di media pemeliharaan pada sistem bioflok, sedangkan Vibrio sp. Hep-1b-8 (2.26%) dan V. parahaemolyticus (0.80%) mendominasi usus udang vaname pada perlakuan kontrol. Sistem bioflok juga mampu meningkatkan aktivitas enzim pencernaan, performa pertumbuhan, dan panjang mikrovili usus secara signifikan (P < 0.05). Kesimpulan dari penelitian ini adalah penerapan sistem bioflok pada budidaya udang vaname mampu memengaruhi komposisi dan kelimpahan komunitas bakteri Vibrio pada lingkungan budidaya maupun pada usus udang, serta meningkatkan performa pertumbuhan dengan aktivitas enzim pencernaan yang lebih baik dan mikrovilli usus yang lebih panjang.
 
 Kata kunci: bioflok, biokontrol, microbiota, udang vaname, Vibrio

Preservation of Pacific white shrimp (Penaeus vannamei) by pullulan and melleolide composite preservatives

Preservation of Pacific white shrimp (Penaeus vannamei) by pullulan and melleolide composite preservatives

Production of the Macroalgae Ulva lactuca Integrated with the Shrimp Penaeus vannamei in a Biofloc System: Effect of Total Suspended Solids and Nutrient Concentrations

This study focused on evaluating the effect of different concentrations of nutrients and total suspended solids on the removal rate of nutrients and biocompounds from the macroalgae U. lactuca in an integrated system with the shrimp Penaeus vannamei in biofloc. The experiment lasted 45 days and included five treatments with three replicates each, with percentages of 0 (control), 25, 50, 75, and 100% biofloc inoculum (73.3 ± 5.7 and 325.0 ± 21.2 mg L−1 initial nitrate and solids, respectively, in the 100% inoculum), from a shrimp farm, resulting in different concentrations of solids and nutrients. The macroalgae were introduced into 280 L tanks at a density of 0.88 kg m−2, along with 200 shrimp m−3. The algae were separated by a floating structure. Water quality parameters were measured, and the nutrient removal rate was evaluated. The treatment with 75% inoculum showed a removal rate of 55.0 ± 4.0 and 31.0 ± 10.0% of nitrate and phosphate, respectively. There was no difference in macroalgae growth between the treatments; however, macroalgae grown in 75% inoculum had higher protein, chlorophyll-a, and lower ash values compared with the control. The use of macroalgae in integrated production with shrimp under the conditions of the treatment with 75% biofloc inoculum proved to be viable and sustainable.

Intestinal microbiota differences associated with physiological health, meat quality, and regulating mineral interactions of Penaeus vannamei fed organic manganese

The objective of this study was to investigate the effects of organic manganese (Mn) on the health status of white shrimp (Penaeus vannamei) and the potential correlations between intestinal microbiota and host health, meat quality, and mineral interactions. An 8-week experiment was designed with 7 dietary treatments: C0, no Mn supplementation; S20, 20 mg/kg Mn from MnSO4·H2O (inorganic); SO, 10 mg/kg inorganic Mn and 5 mg/kg Mn from Mn-proteinate (organic); O10, O20, O30 and O40, 10, 20, 30 and 40 mg/kg organic Mn, respectively. The 840 shrimp (approximately 5.30 g) were randomly allocated into 21 tanks, with each diet group containing 3 tanks and each tank accommodating 40 shrimp. The results showed that 10 mg/kg organic Mn supplementation is optimal to replace 20 mg/kg inorganic Mn. Compared with inorganic Mn, organic Mn shaped healthier intestinal microbiota communities and enhanced the competitive advantage of shrimp for Mn uptake, which resulted in promoting nutrition metabolism (higher apparent digestibility coefficient (ADC) of crude protein (P = 0.031) and concentrations of glucose (P = 0.013), triglyceride (P < 0.01) and total cholesterol (P < 0.001)), enhancing antioxidant capacity and immune response (P < 0.05), improving meat quality (P < 0.05), and regulating iron content in whole body and muscle, zinc content in muscle and ADC of copper and zinc (P < 0.01). Pearson's correlations were observed between gene expression analysis of the immune response and antioxidant capacity, Crude proteinADC, meat texture, and dietary organic Mn, between ADC of copper and zinc, muscle content of iron and zinc (r = 0.55, 0.79, 0.93, −0.91, −0.90, respectively, P < 0.001). In conclusion, organic Mn affects shrimp health status, meat quality and mineral interactions which correlate with changes of the intestinal microbiota.

PvMR1, a novel C-type lectin plays a crucial role in the antibacterial immune response of Pacific white shrimp, Penaeus vannamei

C-type lectins (CTLs) are important immune molecules in innate immune, which participate in non-self recognition and clearance of pathogens. Here, a new CTL with two distinct C-type lectin domains (CTLDs) from Pacific white shrimp Penaeus vannamei, designated as PvMR1 was identified. The obtained PvMR1 coding sequence (CDS) was 1044 bp long encoding a protein with 347 amino acids. PvMR1 had two CTLD, a conserved mannose-specific EPN motif and a galactose-specific QPD motif, clustering into the same branch as the crustacean CTLs. PvMR1 was widely distributed in shrimp tissues with the highest transcription level in the hepatopancreas, with significantly induced mRNA expression on the hepatopancreas and intestines after immune challenge with Vibrio anguillarum. In vitro assays with recombinant PvMR1 (rPvMR1) protein revealed that it exhibited a wide range of antimicrobial activity, bacterial binding ability, and bacterial agglutination activity in a Ca2+-independent manner. Moreover, PvMR1 promoted bacterial phagocytosis in hemocytes. Furthermore, rPvMR1 treatment could significantly enhance the bacterial clearance in hemolymph and greatly improved the survival of shrimp under V. anguillarum infection in vivo. These results collectively suggest that PvMR1 plays an important role in antibacterial immune response of P. vannamei.

Acute effects of the environmental probiotics Rhodobacter sphaeroides on intestinal bacteria and transcriptome in shrimp Penaeusvannamei

In recent years, a substantial number of studies have been dedicated to exploring the potential benefits of probiotics in aquaculture. Rhodobacter sphaeroides can be used in aquaculture-related environmental bioremediation, and its protein is also used as a feed additive in Penaeus vannamei culture. To investigate the effects of releasing R. sphaeroides as environmental probiotics on P. vannamei, we employed 16S rRNA gene and mRNA transcriptome sequencing. Our study focused on assessing alterations in intestinal bacteria and intestinal gene expression in P. vannamei, establishing correlations between them. Our findings revealed a significant increase in the relative abundances of Rhodobacter, Paracoccus, Sulfitobacter, and other bacterial OTUs within the intestinal bacterial community. Additionally, we observed enhanced complexity and stability in the intestinal bacterial correlation network, indicating improved synergy among bacteria and reduced competition. Moreover, the introduction of R. sphaeroides resulted in the down-regulation of certain immune genes and the up-regulation of genes linked to growth and metabolism in the intestinal tissues of P. vannamei. Importantly, we identified a noteworthy correlation between the changes in intestinal bacteria and these alterations in intestinal tissue gene expressions. By conducting analyses of the intestinal bacterial community and intestinal tissue transcriptome, this study revealed the effects of releasing R. sphaeroides as sediment probiotics in P. vannamei culture water. These results serve as vital scientific references for the application of R. sphaeroides in P. vannamei aquaculture.

The effects of dietary black cumin (Nigella sativa) seed meal on immune response of Pacific white shrimp (Penaeus vannamei)

ABSTRACT The black cumin (Nigella sativa) seed (BCS) is known as an immunostimulant herb owing to its enhancing effects on nonspecific immune systems. However, the effectiveness of dietary BCS on shrimp immune systems has not been well known. Therefore, the present study evaluated the effects of the experimental diets containing 0 (control), 5 (BCS5), 15 (BCS15), 30 (BCS30), and 50 (BCS50) g kg−1 (BCS) on immune response of Pacific white shrimp (Penaeus vannamei). The results showed significant decrease in plasma glucose, globulin, ALP activity and hyaline cells and increase of semigranular cells in shrimp fed up to 30 g kg−1 BCS compared to the control group (p < 0.05). Moreover, significant upregulation of α2-macroglobulin (α2-M), integrin β, and peroxinectin (PX) transcripts was observed during the course of the experiment in all treatments (p < 0.05). The transcripts of PX and integrin β showed a significant decrease in BCS fed shrimp after exposure to V. harveyi (p < 0.05). In conclusion, supplementation of BCS in the diet of shrimp for 90 days and after exposure to V. harveyi could significantly affect some immunological indices and the expression of some immunity related biomarkers.