Pacific White Shrimp Penaeus Vannamei Research Articles

WSV403 suppresses JAK/STAT signaling to impair antiviral resistance in Pacific white shrimp Penaeus vannamei

Viral immediate early (IE) genes are key regulators of host antiviral defenses. White spot syndrome virus (WSSV) IE gene WSV403 encodes an E3 ligase which regulates the latency state of WSSV. However, the role of WSV403 in host immune response remains unclear. Here, we generated a transgenic Drosophila line that overexpresses WSV403 and found that WSV403 suppresses the JAK/STAT pathway and its downstream genes, leading to increased susceptibility and viral load upon Drosophila C virus infection. We further showed that WSV403 suppresses Stat92E expression without affecting its phosphorylation or degradation, suggesting a novel mechanism of JAK/STAT inhibition. Moreover, we demonstrated that knockdown of WSV403 in the Pacific white shrimp Penaeus vannamei reduces WSSV replication and enhances transcript levels of JAK/STAT pathway components. Our results revealed the immune modulatory function of WSV403 and uncovered a new mechanism by which WSSV inhibits host JAK/STAT signaling to impair antiviral resistance against WSSV infection.

Time course of acute hepatopancreatic necrosis disease (AHPND) in the Pacific white shrimp Penaeus vannamei by wet mount analysis

Time course of acute hepatopancreatic necrosis disease (AHPND) in the Pacific white shrimp Penaeus vannamei by wet mount analysis

Comparison of Growth Performance and Biochemical Components between Low-Salinity-Tolerant Hybrid and Normal Variety of Pacific White Shrimp (Penaeus vannamei).

Penaeus vannamei, a high-yield economical shrimp, is confronting germplasm degradation in the culture environments found in China, which results in a sharp drop in production. Genetic improvement by hybridization is an effective way to solve this problem. In this study, we selected the hybrid species adapted to low-salinity culture obtained by intraspecific crossing as the experimental group. The control group consisted of normal variety from the Hainan Lutai Company. The two groups of shrimps were cultured for three months under salinities of 1 PSU, 5 PSU, and 15 PSU. Growth-performance-related indicators, biochemical composition, and molting-related gene expression were examined. The results showed that at salinities of 1 PSU and 5 PSU, the survival rate and growth performance of the low-salt breeding group were better than those of the normal variety population. The digestive enzyme activity in the low-salt breeding group was higher, which was consistent with its better growth performance, and was also associated with higher triglyceride, total cholesterol, and glycogen content. Lower levels of lactic acid indicated less anaerobic metabolism and better adaptability to the environment. The amino acid and fatty acids analysis showed that levels of essential amino acids and high unsaturated fatty acids were both higher in the low-salt breeding group than in the normal variety shrimp cultured in a low-salinity environment. The expression levels of genes associated with molting (CHS, CaMKI, RXR, EcR, HSP60, and HSP70) were also higher in the low-salt breeding group than in the control group. The results indicated that the hybrid shrimp showed better growth performance and nutritional advantages compared with the normal shrimp under salinities of 1 PSU and 5 PSU. This research provides a valuable reference for subsequent genetic breeding and shrimp culture.

Identification of CCCH-type zinc finger antiviral protein 1 (ZAP) gene from Pacific white shrimp (Penaeus vannamei): Characterization and expression analysis in response to viral infection.

Zinc-finger proteins (ZFPs) are a huge family that exert multiple roles in the cells. ZFPs could be divided into nine types based on the numbers and positions of conserved Cys and His residues, in which CCCH-type ZFP was one of the most widely studied types. CCCH-type zinc finger antiviral protein 1 (ZAP), a CCCH-type ZFP that can inhibit the replication of certain RNA viruses and DNA viruses by mediating degradation of viral RNA and repressing mRNA translation, plays significant roles in the host innate immune defenses against viral infections. Presently, there have been numerous reports investigating the antiviral ability of ZAP, while no data is available about ZAP gene in the species of shrimps or even crustaceans. In this study, a novel protein containing CCCH-type zinc finger motifs (ZnF-CCCH), CCCH-type zinc finger antiviral protein 1 (ZAP) gene, was identified from Pacific white shrimp (Penaeus vannamei) and its role in antiviral immunity was further investigated. Similar to mammalian ZAPs, in addition to ZnF-CCCH, PvZAP also possesses central WWE domains and C-terminal PARP domain. Phylogenetic analysis showed that PvZAP was close to that of the crustacean Pacific oyster, separating from the cluster of vertebrate ZAP proteins. Upon in vivo infection by IHHNV, gene expression of PvZAP was strongly up-regulated in the hepatopancreas and gills of both adult and juvenile shrimps, where adult individuals showed higher fold changes of up-regulation than in juvenile individuals. These results suggested that PvZAP might play an important role in the innate immune defense of Pacific white shrimp against IHHNV infection. This allows us to gain new insights into the immunological function of ZAP in the innate immunity of shrimp species and even crustaceans.

Microbial signature profiles of Penaeus vannamei larvae in low-survival hatchery tanks affected by vibriosis.

Vibriosis is caused by some pathogenic Vibrio and produces significant mortality in Pacific white shrimp Penaeus (Litopenaeus) vannamei larvae in commercial hatcheries. Acute hepatopancreatic necrosis disease (AHPND) is an emerging vibriosis affecting shrimp-producing countries worldwide. Zoea 2 syndrome is another type of vibriosis that affects the early stages of P. vannamei larvae. Although the pathogenesis of AHPND and zoea 2 syndrome is well known, there is scarce information about microbial composition and biomarkers of P.vannamei larvae affected by AHPND, and there is no study of the microbiome of larvae affected by zoea 2 syndrome. In this work, we characterized the microbiome of P. vannamei larvae collected from 12 commercial hatchery tanks by high-throughput sequencing. Seven tanks were affected by AHPND, and five tanks were affected by zoea 2 syndrome. Subsequently, all samples were selected for sequencing of the V3-V4 region of the16S rRNA gene. Similarity analysis using the beta diversity index revealed significant differences in the larval bacterial communities between disease conditions, particularly when Vibrio was analyzed. Linear discriminant analysis with effect size determined specific microbial signatures for AHPND and zoea 2 syndrome. Sneathiella, Cyclobacterium, Haliea, Lewinella, among other genera, were abundant in AHPND-affected larvae. Meanwhile, Vibrio, Spongiimonas, Meridianimaribacter, Tenacibaculum, among other genera, were significantly abundant in larvae affected by zoea 2 syndrome. The bacterial network at the phylum level for larvae collected from tanks affected by AHPND showed greater complexity and connectivity than in samples collected from tanks affected by zoea 2 syndrome. The bacterial connections inter Vibrio genera were higher in larvae from tanks affected by zoea 2 syndrome, also presenting other connections between the genera Vibrio and Catenococcus. The identification of specific biomarkers found in this study could be useful for understanding the microbial dynamics during different types of vibriosis.

Engineering a replication-incompetent viral vector for the delivery of therapeutic RNA in crustaceans.

Viral disease pandemics are a major cause of economic losses in crustacean farming worldwide. While RNA interference (RNAi)-based therapeutics have shown promise at a laboratory scale, without an effective oral delivery platform, RNA-based therapy will not reach its potential against controlling viral diseases in crustaceans. Using a reverse-engineered shrimp RNA virus, Macrobrachium rosenbergii nodavirus (MrNV), we have developed a shrimp viral vector for delivering an engineered RNA cargo. By replacing the RNA-dependent RNA polymerase (RdRp) protein-coding region of MrNV with a cargo RNA encoding green fluorescent protein (GFP) as a proof-of-concept, we generated a replication-incompetent mutant MrNV(ΔRdRp) carrying the GFP RNA cargo resulting in MrNV(ΔRdRp)-GFP. Upon incorporating MrNV(ΔRdRp)-GFP in the diet of the marine Pacific white shrimp (Penaeus vannamei), MrNV(ΔRdRp) particles were visualized in hemocytes demonstrating successful vector internalization. Fluorescence imaging of hemocytes showed the expression of GFP protein and the MrNV capsid RNA (RNA2) as well as the incorporated GFP RNA cargo. Detection of cargo RNA in hepatopancreas and pleopods indicated the systemic spread of the viral vector. The quantitative load of both the MrNV RNA2 and GFP RNA progressively diminished within 8 days postadministration of the viral vector, which indicated a lack of MrNV(ΔRdRp)-GFP replication in shrimp. In addition, no pathological hallmarks of the wild-type MrNV infection were detected using histopathology in the target tissue of treated shrimp. The data unequivocally demonstrated the successful engineering of a replication-incompetent viral vector for RNA delivery, paving the way for the oral delivery of antiviral therapeutics in farmed crustaceans.

Cultured Penaeus vannamei in Korea co‐infected with white spot syndrome virus and decapod hepanhamaparvovirus

AbstractIn this study, Pacific white shrimp (Penaeus vannamei), pond water, crab, Helice tridens, and live food samples were collected from farms in three provinces of Korea to investigate the presence of white spot syndrome virus (WSSV) and decapod hepanhamaparvovirus (DHPV). By polymerase chain reaction (PCR), DHPV was detected in all shrimp samples (83 of 83); among these, 41 samples were detected with WSSV. Amplicon sequencing and phylogenetic analyses indicated that all DHPV samples were classified as a novel genotype of DHPV. Additionally, the collected squid, polychaeta, and crab were also confirmed to be detected with novel genotypes of DHPV. By WSSV quantitative PCR, the average concentrations of viruses detected in shrimp and pond water samples were 2.58 × 107 copies/μL and 1.27 × 102 copies/μL, respectively. Simultaneous detection of WSSV and DHPV was observed in shrimp, pond water, and crab samples, and co‐infection with both viruses in shrimp could be demonstrated by histopathological analysis. Viral infection can result in significant economic losses in shrimp production. Therefore, precise monitoring and management of WSSV and DHPV prevalence in pond water, live food, and habitats are essential to preventing the spread of viral diseases in the Korean shrimp culture industry.

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.

C-Jun N-terminal kinase activation contributes to improving low temperature tolerance via regulating apoptosis in the Pacific white shrimp Penaeus vannamei.

Temperature is an essential environmental factor for the survival of aquatic animals. Low temperature stress can induce mitochondria to produce excessive ROS and free radicals, and destroy homeostasis. c-Jun N-terminal kinase (JNK) is involved in regulating various physiological processes, including inflammatory responses, cell cycle, reproduction, and apoptosis. Here, we investigated the mechanism of ROS/JNK pathway under low temperature stress both in vitro and in vivo. In this study, transcriptome analysis revealed that apoptosis, autophagy, calcium channel, and antioxidant were involved in the mediation of low temperature tolerance in Pacific white shrimp (penaeus vannamei). PvJNK was activated in response to low temperature stress. Treatments with different temperature caused oxidative stress as demonstrated by increased intensity of the ROS indicator H2DCF-DA, and induced apoptosis as confirmed by indicator FITC. Pretreatment with N-acetylcysteine, an ROS scavenger, attenuated low temperature induced apoptosis, and inhibited the expression of PvJNK. In addition, we demonstrate that mediator PvJNK translocated to nuclear through interacting with PvRheb. By using flow cytometry, inhibiting PvJNK can increase the expression of apoptosis related genes, accelerate tissue damage, and induce ROS and cell apoptosis. The ultimate inhibition of PvJNK accelerates the mortality of shrimp under low temperature stress. Overall, these findings suggest that during low temperature stress, PvJNK was activated by ROS to regulates apoptosis via interacting with PvRheb to promote PvJNK into the nucleus and to improve low temperature tolerance of shrimp.

Genetic parameters for growth and morphological traits of the Pacific white shrimp Penaeus vannamei from a selective breeding programme in the industrial sector of Ecuador

This study aimed to estimate the genetic parameters of growth-related traits (weight and length), morphological traits (cephalothorax, abdomen, length, height, segment width and volume), and the correlated response of weight traits via the selection for morphological traits to evaluate the relative efficiency of indirect selection in P. vannamei from a selective breeding growth programme, PMG-BIOGEMAR®, under industrial production conditions in Ecuador. A total of 595 shrimps from 89 full-sibling families were reared under an extensive culturing system (estuaries) (PRODUMAR, Duran, Ecuador), and were evaluated for genetic parameters at harvest size. The heritability of growth traits was moderate-medium (0.25–0.34), whereas it was quite variable for morphological traits (0.01–0.77). Among the morphological traits, Sixth Segment Width (SW6) (0.77) and Sixth Segment Volume (SV6) (0.35) had medium-high heritability, and genetic correlations between almost all morphological and growth traits were high and positive, except those corresponding to the fourth segment. According to these genetic parameters, SW6 and SV6 as the correlated response to weight are 9.7% and 5.8%, respectively, being more efficient than direct selection for weight. Thus, the sixth segment should be considered an indirect selection criterion for growth in future breeding programmes as it is a precise, non-invasive, and low-cost morphological trait for growth improvement in the industrial sector.

Growth, Biochemical Characteristics, Flesh Quality, and Gut Microbiota of the Pacific White Shrimp (Penaeus vannamei) Fed a Defatted Superworm (Zophobas atratus) Larvae Meal.

This study evaluated the effects of defatted superworm (Zophobas atratus) larvae meal (DBWLM) as an alternative protein ingredient for juvenile Pacific white shrimp (Penaeus vannamei). Six isonitrogenous and isolipidic experimental diets were characterized by replacing 0%, 15%, 30%, 45%, 60%, and 75% fish meal (DBWLM0, DBWLM15, DBWLM30, DBWLM45, DBWLM60, and DBWLM75, respectively) with DBWLM on a w/w basis and feeding them to juvenile shrimp (0.34 ± 0.04 g) for 56 days. The results showed that the replacement of up to 75% fish meal by DBWLM had no negative effect on the growth performance of P. vannamei. The survival of shrimp in the DBWLM30 group was the highest, and the weight gain, specific growth rate, feed conversion ratio, condition factor, and apparent digestibility coefficients of dry matter in the DBWLM15 group were the highest. The substitution of DBWLM for fish meal significantly increased the elasticity of flesh, improved the total content of umami amino acids in flesh (aspartic acid, glutamic acid, glycine, and alanine), promoted lipid metabolism in shrimp, and reduced serum lipid levels. With the increase in DBWLM level, serum acid phosphatase, alkaline phosphatase activity, and intestinal inflammatory gene expression (IGF-1 and IL-6) were inhibited, malondialdehyde content decreased, and total antioxidant capacity level and superoxide dismutase activity increased significantly. Histological sections of the hepatopancreas showed that when 60% or more fish meal was replaced, the hepatopancreas atrophied and had irregular lumen distortion, but the cell membrane was not damaged. Microbiome analysis showed that the abundance of Bacteroidetes and Firmicutes increased and the abundance of Proteobacteria decreased in the DBWLM replacement group, and it was rich in "metabolism"-related functional pathways. It is worth mentioning that the expression of amino-acid-related enzymes was upregulated in the DBWLM15 and DBWLM30 groups, and the DBWLM75 group inhibited the biosynthesis of steroids and hormones. To conclude, the replacement of 15%-45% fish meal with DBWLM can result in better growth and immune status, improved meat elasticity, and reduced inflammation in P. vannamei. However, it is recommended that the replacement level should not exceed 60%, otherwise it will cause atrophy of hepatopancreas cells.

Application of microsatellite DNA method in determining the genetic diversity of farmed broodstocks of Penaeus vannamei (Boone, 1931) in hatchery centers of Bushehr Province

The aim of this study was a detection of different populations of Pacific white shrimp (Penaeus vannamei Boone, 1931) farmed broodstocks and to determine their genetic indexes in hatchery centers of Bushehr province. DNA was extracted from the muscle tissue of 30 broodstocks of 11 stocks using a commercial kit. The repeated sequences were amplified using ten specific primers by PCR in the Iranian Shrimp Center. The results showed that the number of alleles was 4.5-5.5 in the studied stocks. The most allele frequency was observed in the farmed broad stocks of the third stock in the H2 hatchery center, 5.2 ± 0/359. Also, the average of observed heterozygosity in the farmed broad stocks of the second stock in the H5 hatchery center obtained 0.669 ± 0.152, more than other stocks in all centers. Genetics indexes of the farmed broad stocks of the third stock in the H2 hatchery center were increased compared with other stocks in Bucher province. The inbreeding coefficients of the first stocks in the H1 and H3 hatchery centers were significantly more than others, respectively, 0.595 ± 0.105 and 0.547 ± 0.145. The increased inbreeding coefficients of the farmed broad stocks in these stocks can be referred to due to the small size of the founder population and biased selection programs. However, this amount is acceptable according to the information of the other hatchery centers in Bushehr province and other countries. Moreover, it was concluded that broodstock with higher diversity should be used to increase the genetic indicators in the hatchery centers.

Aspergillus niger confers health benefits and modulates the gut microbiota of juvenile Pacific white shrimp (Penaeus vannamei) under farming conditions

IntroductionThe fungus Aspergillus niger is found to be predominant in the body of Pacific white shrimp (Penaeus vannamei); however, its role in shrimp’s health has not been explored. This study aimed to evaluate the influences of A. niger on growth, antioxidative activity, immune response, and gut microbiota of juvenile Pacific white shrimps under farming conditions.MethodsShrimps (2.30±1.05 g) were fed diets supplemented with 0 (control), 1.5 (A1.5), or 3.0 g/kg diet of A. niger (A3.0) for one month. At the end of the study, the growth, antioxidant enzyme activity and immune parameters, and gut microbiota in shrimps fed with different experimental diets were analyzed.ResultsThe results showed a significant increase in weight gain, specific growth rate, and length gain of shrimps in A1.5, compared with other groups (P<0.05). With the exception of lysozyme in both A1.5 and A3.0, which were lower than in the control, the activity of superoxide dismutase (SOD), catalase, acid phosphatase, alkaline phosphatase, and phenol oxidase was higher than those in the control. Gene expressions of SOD, anti-lipopolysaccharide factor-ALF1, and ALF2 (in A1.5 and A3.0) and nitric oxide synthase, penaeidin-PEN2 (in A1.5) and PEN3 and PEN4 (in A3.0) were significantly up-regulated compared to the control (P<0.05). The addition of A. niger increased diversity and separated the microbial community in the gut of shrimps. At the phylum level, Firmicutes and Bacteroidota were dominant, and Proteobacteria was less abundant in the A1.5 and A3.0, as compared to the control. At the genus level, the relative abundance of Vibrio, Marivita, and Roseobacter was increased but Ruegeria was decreased in A1.5 and A3.0 when compared to the control. The genera Edwardsiella, Clostridium sensu stricto 1, and Shimia in the A1.5 were higher than in the control.DiscussionThese findings demonstrated the beneficial effects of A. niger on growth, health, and changes in the gut microbiota in shrimps under farming conditions. The recommended concentration of A. niger in the diet for shrimps is 1.5 g/kg diet.

Rapid Detection of DNA and RNA Shrimp Viruses Using CRISPR-Based Diagnostics.

Timely detection of persistent and emerging pathogens is critical to controlling disease spread, particularly in high-density populations with increased contact between individuals and limited-to-no ability to quarantine. Standard molecular diagnostic tests for surveying pathogenic microbes have provided the sensitivity needed for early detection, but lag in time-to-result leading to delayed action. On-site diagnostics alleviate this lag, but current technologies are less sensitive and adaptable than lab-based molecular methods. Towards the development of improved on-site diagnostics, we demonstrated the adaptability of a loop-mediated isothermal amplification-CRISPR coupled technology for detecting DNA and RNA viruses that have greatly impacted shrimp populations worldwide; White Spot Syndrome Virus and Taura Syndrome Virus. Both CRISPR-based fluorescent assays we developed showed similar sensitivity and accuracy for viral detection and load quantification to real-time PCR. Additionally, both assays specifically targeted their respective virus with no false positives detected in animals infected with other common pathogens or in certified specific pathogen-free animals. IMPORTANCE The Pacific white shrimp (Penaeus vannamei) is one of the most valuable aquaculture species in the world but has suffered major economic losses from outbreaks of White Spot Syndrome Virus and Taura Syndrome Virus. Rapid detection of these viruses can improve aquaculture practices by enabling more timely action to be taken to combat disease outbreaks. Highly sensitive, specific, and robust CRISPR-based diagnostic assays such as those developed here have the potential to revolutionize disease management in agriculture and aquaculture helping to promote global food security.

Temperature and fasting effect on compensatory growth and transcriptomic response in the Pacific white shrimp Penaeus vannamei

During the cultivation of the Pacific white shrimp, Penaeus vannamei, environmental modifications can generate stress and alter the expected growth of organisms. When stress is temporary and conditions for growth are restored, shrimp may exhibit an accelerated growth rate known as compensatory growth (CG), reaching partially or fully the weight of non-stressed organisms. However, the CG response capacity is limited, and a point of no return (PNR) occurs when stress is extreme. The aim of this study was to evaluate the effect of temperature changes and temporary fasting on the transcriptomic CG response of P. vannamei. Post-larvae (0.75 ± 0.05 g avg. wt.) were exposed to different stress periods with fasting for 3, 7, and 14 days at three temperatures each (22 °C, 26 °C, and 30 °C), followed by a recovery stage of feeding ad libitum and temperature at 30 °C for the remaining time of five experimental weeks. Treatments were compared with a control group fed to satiety at 30 °C throughout the experiment. Specific growth rate (SGR, % day−1), weight gain (WG), survival (S), feed intake (FI), and feed conversion ratio (FCR) were determined weekly, and muscle was sampled for differential gene expression (DGE) analysis. Organisms exposed to 3 days of fasting reached the same weight as the control group, which indicated a complete CG. Within this group, those submitted to 26 °C showed lower FI and FCR than shrimps exposed at 22 °C and 30 °C (8% less feed consumption), suggesting a more efficient use of nutrients from the diet. On the other hand, the organisms exposed 14 days to fasting reached a PNR, and the WG reduction was >50%. The DGE concerning the control group showed 862 genes during CG and 449 genes in shrimps that reached the PNR. Up-regulation of genes related to energy homeostasis, muscle growth, and molting was observed during CG, whereas those involved in the cellular response to DNA damage stimulus were down-regulated. In contrast, genes related to oxidative stress response were up-regulated, and genes involved in molting and metabolic processes were down-regulated in organisms that reached a point of no return. Short-term fasting is an effective strategy to optimize feed use in shrimp farming without decreasing the final biomass.

Effects of high-humidity hot air impingement cooking on physicochemical properties and microstructure of Pacific white shrimp (Penaeus vannamei)

In this study, the potential of high-humidity hot air impingement cooking (HHAIC) was investigated as an alternative to other conventional cooking methods, including steaming, boiling, and roasting, by assessing the physicochemical properties, taste profile, and sensory evaluations of Pacific white shrimp (Penaeus vannamei). Compared to the steamed-, boiled-, and roasted-treated shrimp, HHAIC-treated samples demonstrated a lower cooking loss between 3.19% and 16.47%, which was possibly attributed to the decreasing muscle rupture. Moreover, HHAIC-treated samples exhibited improved textural properties, higher color retention, better water-holding capacity, and higher degree of polyphenol oxidase inactivation. By low-field nuclear magnetic resonance imaging, HHAIC-treated shrimp showed a pretty uniform water distribution. The main secondary structures of protein in fully-cooked P. vannamei shrimp were β-sheets and β-turns with no significant difference in free amino acid content among the four methods. Therefore, HHAIC could be considered a novel thermal technique for high-quality shrimp products as well as for other aquatic products.

Transcriptomic analysis of the hepatopancreas of white shrimp Penaeus vannamei following experimental infection with the Vibrio parahaemolyticus TJA114

The Pacific white shrimp (Penaeus vannamei) is an economic breeding species with the largest annual production of penaeid shrimp worldwide. Besides the V. parahaemolyticus strains causing acute hepatopancreatic necrosis disease (AHPND), the non-AHPND V. parahaemolyticus strains also cause severe disease leading to significant economic losses in the shrimp. A non-AHPND V. parahaemolyticus strain, named TJA114, isolated from P. vannamei with vibriosis exhibited strong pathogenicity toward the shrimp. To better understand the pathogenesis of P. vannamei in the early stage of non-AHPND V. parahaemolyticus infection, we performed mRNA sequencing for the hepatopancreas between the control and the V. parahaemolyticus-challenged groups at six hours post-infection. We identified 916 differentially expressed genes: 550 up-regulation and 366 down-regulation in the challenged shrimp. GO terms related to immunity and metabolism were annotated, including biological adhesion, response to stimulus, metabolic process, binding, and cellular process. KEGG pathways related to fatty acid elongation, C-type lectin receptor signaling and complement and coagulation cascades were significantly influenced by the V. parahaemolyticus infection. This study provides insights into the mechanisms by which P. vannamei responds to early infection with the non-AHPND V. parahaemolyticus.

Metabolic and osmoionic effects of the recombinant crustacean hyperglycemic hormone (rCHH-A) of the Pacific white shrimp Penaeus vannamei on specimens acutely exposed to extreme salinities

The crustacean hyperglycemic hormone (CHH) is a multifunctional neuropeptide that plays a central role in crustacean metabolism and physiology. Experiments were conducted to examine the metabolic and osmoionic capabilities of the white shrimp Penaeus vannamei injected with its recombinant CHH-A (rCHH-A) peptide and acutely transferred from iso- (26 ppt) to hypo- (10 ppt) and hyper-osmotic (40 ppt) conditions. Hemolymph glucose, protein, osmoregulatory capacity (OC), and ionoregulatory capacity (IC) for sodium, chloride, potassium, and calcium were evaluated at four post-injection times (0.5, 1, 2, and 24 h). The rCHH-A peptide had hyperglycemic activity in all salinity conditions, obtaining maximum values at 1 h post-injection. However, in shrimp transferred to hyper-osmotic condition, rCHH-A caused the most significant reductions in OC (2 h), chloride IC (2 h), and total proteins (0.5-2 h) compared to the phosphate-buffered saline (PBS) control. Contrastingly, in shrimp transferred to hypo-osmotic conditions, rCHH-A decreased OC significantly from 2-24 h, strongly decreased chloride and potassium IC at 1 h post-injection, and increased total protein concentration in the hemolymph (1-2 h) when compared to PBS control. Concerning calcium, the rCHH-A injection decreased calcium IC at 10 ppt (1 h) and 26 ppt (2 h), providing insight into a potential role for CHH-A in calcium regulation. The results suggest that glucose and protein mobilization could enhance energy for osmo-ionic regulation under extreme osmotic conditions. This research study contributed to understanding crustacean endocrinology in P. vannamei and related euryhaline crustaceans. Further research should be performed to understand the osmo- and ionoregulatory mechanisms of the different CHH variants in crustaceans exposed to other stress conditions and the relationship with intermediary energy metabolism regulation.

Hemato-immunological parameters can be influenced by microalgae addition and fish feed supplementation in the integrated rearing of Pacific white shrimp and juvenile Nile tilapia using biofloc technology

This study evaluated the effects of microalgae (Scenedesmus obliquus) addition and fish feed supplementation on hemato-immunological parameters of Pacific white shrimp (Penaeus vannamei) and juvenile Nile tilapia (Oreochromis niloticus) cultured in integration using biofloc technology for 62 days. The experiment was designed as a factorial design with two factors, totaling four experimental groups: (1) No addition of microalgae and no addition of fish feed; (2) no addition of microalgae and addition of fish feed; (3) addition of microalgae and no addition of fish feed; and (4) addition of microalgae and addition of fish feed. In all groups shrimp were fed according to a feeding table. Shrimp (2.16 ± 0.01 g) and fish (1.53 ± 0.12 g) were cultured under densities of 400 shrimp m−3 and 522 fish m−3 in 800 L and 90 L (useful volumes) tanks maintained under water recirculation. Microalgae was added two times a week for a final concentration of 5 mg L−1 in the units, while a commercial fish feed was provided at the rate of 1% of the fish biomass daily. At the end of the trial, the fish and shrimp were sampled for the hemato-immunological analyses. As regards the shrimp, there was a significant effect of the interaction on total hemocyte count (p < 0.05), in which the highest value occurred in the group with microalgae/no fish feed addition. There was also a significant effect of microalgae addition on serum protein (p < 0.05), with the highest values occurring in the treatments that employed microalgae. In the case of the fish, the monocyte count was significantly affected by the fish feed addition (p < 0.05), the highest values being observed when the feed was provided. There were also significant effects of the interaction and of microalgae addition on mean corpuscular volume and mean corpuscular hemoglobin concentration (p < 0.05), with the highest values occurring in the group that received microalgae but no fish feed and in the groups that did not receive microalgae, respectively. Overall, these results suggest an enhanced immunological status for the shrimp due to increases in total hemocyte count and high serum protein concentration when microalgae was added and an improved nutritional status for the fish that received feed due to increased circulating monocytes, along with possible greater erythrocyte stability when microalgae was added.

Benzoic Acid Inclusion Effects on Health Status and Growth Performance of Juvenile Pacific White Shrimp Penaeus vannamei

AbstractOrganic acids and their salts are used as additives in aquafeeds, as their participation in some metabolic pathways and energy generation in organisms increases the nutritional value. Benzoic acid (BA; C6H5‐COOH), a white crystalline substance with a chemical structure that contains carboxylic acid attached to a benzene ring, is naturally found in plant and animal tissues. It is one of the most used organic acids due to its antifungal properties, and it acts as a preservative for a variety of human consumption products. Additionally, it demonstrates health and growth benefits when included in feeds by modifying the energy metabolism, microbiota, and intestinal tract morphology. Information on BA inclusion in aquatic food is rare, and such information for Pacific white shrimp Penaeus vannamei is nonexistent. This study evaluated the effects on growth, survival, feed conversion ratio, energy content, and health status (through lipid quantification in the hepatopancreas, histological examination, and salinity stress tests) of Pacific white shrimp juveniles by including BA at different concentrations (0.0, 1.0, 1.5, and 2.0 g/kg) in a commercial feed. Diets with BA inclusion produced significant differences in the hepatosomatic index, hepatopancreas lipid content, and histopathological index value (reflecting damage to the hepatopancreas and antennal gland atrophy) at all BA concentrations. The lowest survival obtained was 94.44% at a BA concentration of 1.0 g/kg. The feed conversion ratio was in accordance with the range established by the Food and Agriculture Organization of the United Nations except for values obtained at 0 g/kg. Calorimetric analysis and BA detection in muscle revealed no significant differences between concentrations. Due to the results obtained in this study, the evaluated inclusions of BA are not recommended for use in juvenile Pacific white shrimp diets.