Shrimp Survival Research Articles

Dietary montmorillonite clay improved Penaeus vannamei survival from acute hepatopancreatic necrosis disease and modulated stomach microbiota

Acute hepatopancreatic necrosis disease (AHPND) is causing a bacterial pandemic in shrimp farming. AHPND is caused by pathogenic strains of Vibrio parahaemolyticus (VPAHPND) that produces the bacterial toxins, PirA and PirB. Shrimp exposure to AHPND-causing bacteria is hypothesized to be through the oral route, ingested into the gut where the bacteria initially colonized the stomach and then releases the binary toxins to damage the hepatopancreas. In view of changing global regulatory controls on the use of antibiotics, there is much interest in the development of functional aquafeeds. One innovative method to mitigate AHPND is to bind the bacterial toxins by adding adsorbent clay minerals into shrimp feeds. A feeding trial using triplicate groups of Penaeus vannamei post-larvae (PL30) was conducted to evaluate the efficacy of a montmorillonite (MMT) clay [Calibrin®-Z (CL)] on growth, gut health and disease resistance to AHPND. The addition of 0.25% or 0.50% CL did not significantly (P > 0.05) impact growth and feed utilization efficiency compared to control groups fed diets with 0% CL. When challenged with VPAHPND, survival of shrimp fed 0.25% or 0.50% CL were 83.3 ± 5.5% and 93.8 ± 0.1%, respectively, and were significantly higher (P < 0.05) compared to the VPAHPND-challenged positive control group (39.6 ± 10.4%) but not significantly different compared to the unchallenged negative control group (95.8 ± 2.1%). Vibrio and total cultivable bacteria counts in the hepatopancreas of shrimp fed CL-added diets were significantly lower compared to positive control. Hepatopancreas histopathology of infected shrimp fed CL-added diets showed less damage. During AHPND infection, bacterial diversity was depressed but dietary CL tended to restore stomach bacterial richness and α-diversity index. Dietary CL modulated the stomach bacterial community possibly with beneficial impact to shrimp survival. At the phylum level, Proteobacteria and Bacteroidetes were the main groups but the relative abundance of Verrucomicrobia, Acidobacteria and Firmicutes was more prevalent in the microbiota of shrimp fed CL-added diets. Bacteria of the genus Pseudoalteromonas, Tenacibaculum, and Marinimicrobium were identified as members of the healthy microbiota and Lysobacter was observed to be relatively enriched in AHPND-infected shrimp. Demequina was identified as a potential biomarker and was significantly enriched in the stomach of the CL-added groups. This is the first report on the effectiveness of dietary clay mineral in AHPND mitigation. At least 0.25% CL is suggested to be included in commercial shrimp feeds to mitigate against production and economic losses from AHPND outbreaks in shrimp farms.

Brown sugar addition enhanced nutrient removal rates, growth performance, and bacterial community in a rice straw-based biofloc shrimp culture system

A 30-day culture trial was executed to ascertain the effects of brown sugar addition on nutrient removal, feed conversion ratio, growth performance, and microbial community in a rice straw-based biofloc shrimp system. Twelve indoor experimental barrels were supplied with juvenile pacific white shrimp (Litopenaeus vannamei) with a preliminary mean weight of ∼1.08 ± 0.35 g. The experimental groups comprised four biofloc treatments labeled as (Control-CT, SG1, SG2, and SG3), each with three replicates. The SG groups were the treatments with varying amounts of carbon source (brown sugar) addition. Each experimental barrel was stocked with 100 juvenile shrimps. To maintain the carbon: nitrogen ratio, brown sugar was added daily in varying amounts in the SG treatments but not in the control group (CT). The results demonstrated that the ammonium and nitrite‑nitrogen concentrations in the SG3 (0.45 and 0.34 mg/L) and SG2 (0.58 and 0.43 mg/L) groups were significantly (p < 0.05) lower than the Control (1.18 and 0.88 mg/L). Also, the highest nutrient removal rates for ammonium nitrogen (80%) and nitrite nitrogen (83.79%) were observed in the SG3 treatment. In addition, the SG2 group's feed conversion ratio (0.66) was statistically (p < 0.05) lower than the CT group's (0.83). Compared to the control setup (86%), the SG treatments recorded shrimp survival rates of over 90%. Furthermore, our results revealed that the most dominant microbial phyla in all treatments were Proteobacteria (71.60%), Bacteroidetes (26.60%), Actinobacteria (18.53%), Planctomycetes (8.30%), and Verrucomicrobia (2.40%) which played a significant role in nutrient cycling and promoting water quality. Overall, our study highlighted an innovative ecological farming system that recycles agricultural waste, minimizes inorganic nitrogen levels, and serves as an in-situ food source for sustainable shrimp production.

Indole-3-acetic acid increases the survival of brine shrimp challenged with vibrios belonging to the Harveyi clade.

Vibrios belonging to the Harveyi clade (including closely related species such as Vibrio campbellii, Vibrio harveyi and Vibrio parahaemolyticus) are important pathogens of aquatic organisms. In this study, we investigated the use of indole-3-acetic acid to control disease caused by Harveyi clade vibrios. Indole-3-acetic acid, which can be produced by various seaweeds and microalgae, was added to the rearing water of brine shrimp larvae challenged with 12 different Harveyi clade Vibrio strains. Indole-3-acetic acid significantly decreased the virulence of 10 of the strains without any effect on their growth. The latter is important as it will minimize the selective pressure for resistance development. The survival rate of brine shrimp larvae increased from 1.2-fold to 4.8-fold upon treatment with 400 μM indole-3-acetic acid. Additionally, indole-3-acetic acid significantly decreased the swimming motility in 10 of the strains and biofilm formation in eight of the strains. The mRNA levels of the pirA and pirB toxin genes were decreased to 46% and 42% by indole-3-acetic acid in the AHPND-causing strain V.parahaemolyticus M0904. Hence, our data demonstrate that indole-3-acetic acid has the potential to be an effective virulence inhibitor to control infections in aquaculture.

DL-methionyl-DL-methionine as an efficient methionine source for promoting zootechnical performance and methionine-related pathways in the whiteleg shrimp (Penaeus vannamei).

Methionine (MET) supplementation is a current strategy to achieve shrimp requirement. Notwithstanding, the efficiency of the precisely formulated feeds can be diminished since shrimps are slow eaters and masticate feed externally that results in nutrient leaching. In this regard, a methionine dipeptide (DL-methionyl DL-methionine) benefits the feed industry by reducing MET water solubility while increasing its bioavailability. Therefore, the effects of feeding whiteleg shrimp (Penaeus vannamei) with increasing levels of methionine dipeptide were evaluated on zootechnical performance and methionine-, immune- and antioxidant-related pathways. A 74 d growth trial was conducted by feeding a control diet and four diets supplemented with AQUAVI® Met-Met at 0·08, 0·12, 0·24 and 0·32% of DM. Diet digestibility, body amino acids (AA) composition and nitrogen metabolites, metabolic enzymes, oxidative status and gene expression were evaluated. It can be concluded that graded dietary increase of methionine dipeptide up to 0·24 % for 74 d translated in significant gains on the growth performance, feed efficiency, nutrient and nitrogen gain and shrimp survival. Moreover, it was showed that Met-Met dietary spare leads to an improvement of free-AA pool and nitrogen metabolites concentration and reduces the signs of oxidative stress. Finally, in a closer look to the MET-related pathways passive to be altered by Met-Met spare, a clear modulation of the described antioxidant and cell proliferation routes was detected.

Growth performance and nutritional impact of Moringa oleifera leaf extract as supplemental diets in the juvenile pacific white shrimp (Penaeus vannamei)

Moringa (Moringa oleifera) is widely recognized for its potent medicinal properties and immunostimulant effects. This study aimed to investigate the impact of a hot water extract of moringa leaves on the growth performance, feed conversion ratio, and survival of pacific white shrimp, Penaeus vannamei. Four different diets were used in this experiment, each containing varying levels of moringa leaf extract: 0, 2.5, 5, and 7.5 g/kg of the diet. A total of 1,200 shrimp, with an initial body weight of 0.01 g/individual, were carefully selected to ensure they were free from Vibrio infestation. One hundred shrimp were placed in each circular tank, with a volume of 750 L or 133 individuals per cubic meter. The shrimp were fed the diets four times daily, with a protein content ranging from 13% to 39%, over a period of 30 days. The results of the study revealed that the growth performance and survival rate of the shrimp in the groups that were fed diets supplemented with moringa were significantly higher than those in the control group (without moringa supplementation). The highest growth performance, in terms of specific growth rate, weight gain, and final weight, was observed in the groups of shrimps that were fed diets containing either 2.5 g or 5 g of moringa leaf extract per kilogram of the diet (p&lt;0.05). Furthermore, the diet containing 2.5 g of moringa leaf extract per kilogram resulted in the highest survival rate compared to the other treatment groups. Therefore, it can be concluded that the optimal level of moringa in the diet of vannamei shrimp is 2.5 g/kg of the diet.

Application of inorganic fertilizer combination with various kinds of organic fertilizer in the nursery phase of white shrimp (Litopenaeus vannamei)

The purpose of this research is to determine the effect of natural feed growth on the growth and survival rate of white shrimp, specifically in relation to the usage of inorganic fertilizers in conjunction with various organic fertilizers. The experimental design consisted of four treatments, each replicated three times. The treatments included a combination of urea, SP-36, and organic fertilizer derived from superintensive shrimp pond waste (Treatment A), a combination of urea, SP-36, and petroganic (Treatment B), a combination of urea, SP-36, and chicken manure (Treatment C), and a control treatment consisting of only urea and SP-36 without any organic fertilizer (Treatment D). Urea was administered at a dosage of 5.2 grams per container, SP-36 at a dosage of 2.6 grams per container, and organic fertilizer at a dosage of 52 grams per container. The factors that were monitored included the composition of plankton, the growth of benthic algae, the growth and survival of white shrimp, and the quality of pond water. The study’s findings revealed no statistically significant difference in the growth of live feed when inorganic and organic fertilizers were combined (P&gt;0.05). However, the survival rate of white shrimp exhibited a significant difference (P&lt;0.05). Using a mixture of inorganic fertilizer (namely urea and sp-36) and organic fertilizer, within the context of a super-intensive shrimp pond, yielded the most favorable outcome regarding white shrimp survival rate, with a recorded percentage of 94.67%.

Dietary inclusion of roselle improves body colouration and survival of the whiteleg shrimp (Litopenaeus vannamei) juveniles challenged against Vibrio harveyi

This study was conducted to investigate the use of fresh and heat-treated roselle meals on growth, body colouration, and survival against Vibrio harveyi infection of whiteleg shrimp, Litopenaeus vannamei. Fresh (FR) or heat-treated roselle (HR) meals were added at 10% in isoproteic (38%) and isolipidic (7%) diets. A control diet was prepared without any addition of roselle meal. These diets were fed to shrimp (initial body weight 1.26g±0.02g) in triplicate groups for 8 weeks then challenged with V. harveyi. The growth, feed efficiency, total carotenoid content, and survival of shrimp and total Vibrio spp. counts in the hepatopancreas post-challenge test were estimated. No significant differences were recorded in the growth, survival, and feed utilization of the shrimp fed the roselle-added diets (FR or HR) compared to the control group. A significantly higher total carotenoid concentration was detected in shrimp fed with the FR and HR diets compared to the control (P&lt;0.05). The challenge test with V. harveyi showed that the shrimp specimens fed with FR and HR diets gained higher survival and a lower total number of Vibrio spp. count in the hepatopancreas compared to the control group. The present finding suggests that fresh or heat-treated roselle meals provide a good source of carotenoid and increase the resistance of shrimp against vibriosis without affecting the growth and feed utilization.

Utilization of microalgae, Chlorella sp. UMT LF2 for bioremediation of Litopenaeus vannamei culture system and harvesting using bio-flocculant, Aspergillus niger

Microalgae are well known as autotrophic microorganisms in aquaculture wastewater treatment, however their role in the aquaculture system is rarely explored. The purpose of this study is to evaluate the influence of adding microalgae, Chlorella sp. UMT LF2, on the functionality for bioremediation and growth performance of Whiteleg shrimp, Litopenaeus vannamei in the nursery phase reared in a control culture system. Secondly, the response surface methodology (RSM) was used to investigate further on the optimal condition for the harvesting process of excess microalgae biomass using bio-flocculant from the filamentous fungus, Aspergillus niger. The experimental set-up with Chlorella sp. additions were compared to the control group without the microalgae addition based on the water quality, microalgae biomass and shrimp growth performance. Water samples were collected and underwent in-situ and ex-situ involving nine physicochemical parameters. The results showed that introducing microalgae with zero water exchange as treatment tanks reduced the NH3, NO2− and PO43− during the intermediate until the two days before the 30-day culture period's end. Microalgae also enhanced shrimp survival and growth performance significantly 89% as compared to the control, 68%. Furthermore, the culture with the addition of microalgae maintained pH stability and enhanced dissolved oxygen during daytime in the culture water. Therefore, this finding confirmed that Chlorella sp. UMT LF2 addition is promising in improving rearing environment and nursery performance for L. vannamei in culture system. However, further research is required to demonstrate the harvesting by-product from the culture system and the potential applications.

Dietary selenium supplementation alleviates low salinity stress in the Pacific white shrimp Litopenaeus vannamei: growth, antioxidative capacity and hepatopancreas transcriptomic responses.

Se is an essential trace element associated with animal growth and antioxidant and metabolic processes. However, whether Se, especially organic Se with higher bioavailability, can alleviate the adverse effects of low salinity stress on marine economic crustacean species has not been investigated. Accordingly, juvenile Pacific white shrimp (Litopenaeus vannamei) were reared in two culture conditions (low and standard salinity) fed diets supplemented with increasing levels of l-selenomethionine (0·41, 0·84 and 1·14 mg/kg Se) for 56 d, resulting in four treatments: 0·41 mg/kg under standard seawater (salinity 31) and 0·41, 0·84 and 1·14 mg/kg Se under low salinity (salinity 3). The diet containing 0·84 mg/kg Se significantly improved the survival and weight gain of shrimp under low salinity stress and enhanced the antioxidant capacity of the hepatopancreas. The increased numbers of B and R cells may be a passive change in hepatopancreas histology in the 1·14 mg/kg Se group. Transcriptomic analysis found that l-selenomethionine was involved in the regulatory pathways of energy metabolism, retinol metabolism and steroid hormones. In conclusion, dietary supplementation with 0·84 mg/kg Se (twice the recommended level) effectively alleviated the effects of low salinity stress on L. vannamei by regulating antioxidant capacity, hormone regulation and energy metabolism.

Comparative effects of different bacterial lipopolysaccharides on modulation of immune levels to improve survival of the black tiger shrimp

To prevent loss from disease, immunostimulants have been used as dietary supplements to improve immunity and survival of shrimps. Among the various types of immunostimulants, there is increasing evidence that a diet enriched with bacterial lipopolysaccharide can reduce the mortality rate of shrimp under exposure to pathogens. Here, the immunostimulatory effects of bacterial lipopolysaccharide (LPS) from various bacterial sources were explored. Bacterial LPS was extracted from a shrimp pathogen, Vibrio harveyi and its effects were compared with the commercially available LPS from the non-shrimp pathogen, Escherichia coli. Our results revealed that the LPS from V. harveyi was different in molecular size but contained similar functional groups to that from E. coli. To understand their molecular mechanisms, bacterial LPS from the two sources were applied as a supplementary diet and fed to juvenile shrimp for 4-week feeding period before tissue samples were collected for transcriptomic analysis by next generation sequencing. Gene expression profiling revealed that major immune-related genes such as pattern recognition proteins (PRPs), proteinases and proteinase inhibitors, prophenoloxidase systems (proPO system), antimicrobial peptides (AMPs), signaling transduction pathways, heat shock proteins (HSPs), oxidative stress responses, and other immune-related molecules such as mucins and peritrophins were modulated in the groups of shrimp fed with bacterial LPS from both sources, but at different levels. The results suggest that bacterial LPS could modulate shrimp immune system, and different LPS sources led to different activation of immune pathways. Additionally, metabolic-related genes were affected by LPS, suggesting that energy was required for immune stimulation. In the V. harveyi pathogen challenge trial, all shrimp groups fed with diets containing LPS from both bacterial sources showed better survival than the control group without LPS. When comparing groups fed with LPS supplemented diets, the higher concentration of LPS (8 μg/body weight) from E. coli resulted in a better survival rate than a lower concentration (4 μg/body weight). Conversely, shrimp fed with a diet containing LPS from V. harveyi showed a lower survival rate when a higher dose of LPS (8 μg/body weight) was administered than the group fed with a lower concentration of LPS (4 μg/body weight). This could be due to overstimulation of shrimp immune responses, especially by LPS derived from shrimp pathogens, resulting in a reverse effect. These results confirm that immunity in shrimp upon administration of bacterial LPS depends on the origin and dose of the LPS administered.

Optimal Levels of Fish Meal and Methionine in Diets for Juvenile Litopenaeus vannamei to Support Maximum Growth Performance with Economic Efficiency.

This work investigated the optimal levels of fish meal (FML) and dietary methionine (Met) required for maximum growth performance of juvenile Litopenaeus vannamei with economic efficiency. Four sets of diets were prepared to contain 0.00, 6.00, 12.00 and 18.00% FML. Each set was supplemented with DL-methionyl-DL-methionine (DL-Met-Met) to result in a total dietary Met (Met + Cys) content of 0.58 (1.05), 0.69 (1.16), and 0.82% (1.29%), on a fed basis. Shrimp of 1.00 ± 0.08 g were stocked in 60 outdoor tanks of 1 m3 with 100 shrimp/m2, allowing five replications per dietary group. Shrimp in all the groups were fed 10 times daily for 70 days. In a subsequent trial, dietary protein and amino acid digestibility of four FML groups, but only at high dietary Met levels (~0.82%), were evaluated in 40 60 L indoor tanks (11 replicates per diet) for 93 days with 70 shrimp/m2. Final shrimp survival (92.85 ± 4.82%, mean ± standard deviation), weekly weight gain (1.17 ± 0.08 g), apparent feed intake (13.3 ± 0.5 g of feed per stocked shrimp), and feed conversion ratio (1.18 ± 0.06) were unaffected by dietary FML level and Met content. Gained yield was adversely affected when FML was reduced from 18 and 12% (1156 and 1167 g/m2, respectively) to 0 (1090 g/m2), but no change was observed at 6% (1121 g/m2). A significant interaction was detected between FML level and dietary Met. Under 0 and 6% FML conditions, higher levels of total dietary Met, 0.69 and 0.82%, respectively, were required to maximize shrimp BW. In comparison, at 12 and 18% FML, a dietary Met content of only 0.58% was sufficient. Overall, results indicated the use of FML can be minimized or completely eliminated without major detrimental effects on feed digestibility or shrimp growth performance, as long as proper supplementation of Met is carried out. Diets with 0 FML or with only 6% delivered the highest profit and return on investment compared to diets with higher levels.

Prx4 acts as DAMP in shrimp, enhancing bacterial resistance via the toll pathway and prophenoloxidase activation

Peroxiredoxin (Prx), an antioxidant enzyme family, has been identified as immune modulating damage-associated molecular patterns (DAMPs) in mammals but not in shrimp. Acute non-lethal heat shock (NLHS) that enhances shrimp Penaeus vannamei resistance to Vibrio parahaemolyticus causing acute hepatopancreatic necrosis disease (VPAHPND). Among the five P.vannamei Prxs (LvPrx) isoforms, LvPrx4, the most abundant in unchallenged shrimp hemocytes that was upregulated in hemocytes following NLHS treatment, is of great interest. The escalation of the LvPrx4 monomer in hemolymph of NLHS treated shrimp indicates that it probably acts as DAMP. This study revealed that pre-challenge with rLvPrx4 could prolong VPAHPND-infected shrimp survival, increase prophenoloxidase (proPO) activity and promote Toll pathway-related genes expression mediated by Toll-like receptor (TLR) 1 and 2. The presented findings elucidated the molecular mechanism of LvPrx4 monomer as DAMP in NLHS-induced VPAHPND resistance by inducing the TLR1/2 signaling pathway and the proPO activating system.

Antibacterial activity and immunomodulatory role of a proline-rich antimicrobial peptide SpPR-AMP1 against Vibrio campbellii infection in shrimp Litopenaeus vannamei

Antimicrobial peptides (AMPs) constitute one of the most promising sources of natural molecules used for the design of effective antimicrobial agents alternative to antibiotics. Previously, we have showed that a crab proline-rich AMP designated as SpPR-AMP1 is a potent AMP that exhibited antimicrobial activity against both Gram-positive and Gram-negative bacteria. Here, we demonstrated the importance of SpPR-AMP1 peptide in treating a virulent acute hepatopancreatic necrosis disease (AHPND) Vibrio campbellii VH-639 isolate and eliciting the innate immune response to counter the AHPND infection in shrimp Litopenaeus vannamei. SpPR-AMP1 exhibited a strong antimicrobial activity against V. campbellii VH-639 at MIC value of 0.195–0.39 μM. Scanning electron microscopy (SEM) revealed the membrane disruption potential of SpPR-AMP1 against the V. campbellii VH-639 cells. The in vivo effect of SpPR-AMP1 in shrimp L.vannamei was investigated and the results showed that SpPR-AMP1 was capable of modulating the innate immune response by stimulating the expression levels of AMP transcripts in shrimp hemocytes. Moreover, treatments with SpPR-AMP1 could promote the resistance of shrimp against V. campbellii VH-639 infection as demonstrated by a significant increase in shrimp survival rate and decrease in both the bacterial load and the expression levels of bacterial PirA and PirB toxin gene transcripts in the infected shrimp. These results suggest the potential of SpPR-AMP1 peptide with the combined antimicrobial and immunoenhancing capabilities as promising antimicrobial agent to treat V. campbellii VH-639 causing AHPND infection in shrimp aquaculture.

Protective Effects of Combined Utilization of Quercetin and Florfenicol on Acute Hepatopancreatic Necrosis Syndrome Infected Litopenaeus vannamei.

This study aimed to determine the immunity, survival rate, and disease resistance of Litopenaeus vannamei treated using quercetin and florfenicol alone or in combination, after infection with acute hepatopancreatic necrosis syndrome caused by Vibrio parahaemolyticus (VPAHPND). After infection with VPAHPND, different types of feed were given to the shrimp for 5 days, including a control diet (drug-free), florfenicol only diet (15 mg/kg), quercetin only diet (400 mg/kg), a low-dose florfenicol/quercetin combined diet (200 mg/kg quercetin + 7.0 mg/kg florfenicol), a moderate-dose florfenicol/quercetin combined diet (400 mg/kg quercetin + 15 mg/kg florfenicol), and a high-dose florfenicol/quercetin combined diet (800 mg/kg quercetin + 30 mg/kg florfenicol). The cumulative mortality of shrimp was significantly reduced in the drug combination groups compared with either drug used alone (p &lt; 0.05). The density of Vibrio was significantly lower and the immune parameters were significantly increased in the drug combination groups compared with either drug used alone (p &lt; 0.05). Moreover, in the drug combination groups, the hepatopancreas tubules showed better integrity and structure compared with those when either drug was used alone. Therefore, compared with single drug treatment, the florfenicol and quercetin combination enhanced disease resistance, survival, and immune activity of VPAHPND-infected shrimp. When the combination treatment is used, the dosage of florfenicol can be reduced and a better therapeutic effect is obtained.

Microbial Interactions, Growth, and Health of Aquatic Species in Biofloc Systems

Biofloc technology involves the manipulation of the culture system’s carbon: nitrogen ratio to promote bacterial community growth to convert toxic nitrogenous wastes and organics into functional microbial protein; this protein can then be used as a food source and mediate water quality. Biofloc systems have several advantages, which include improved biosecurity, feed conversion, water use efficiency, and nutrient processing. Analyzing the nutritional value and the relationship between high production of aquacultural practices using biofloc is essential. Many studies have demonstrated that biofloc increases the growth of aquatic species by acting as a food source or providing bioactive compounds. Other than this, the beneficial micro-organisms in biofloc systems contain compounds such as organic acids that could resist the growth of pathogenic microbes. They will also serve as a natural probiotic and increase the immunity and survival of fish and shrimp. This technology could be useful for further integration within many aspects of aquaculture production when microbial interactions are considered. However, future studies must fully understand the principles and mechanisms behind the benefits of interactions between biofloc and cultured fish and crustacean species.

Evaluation of aqueous magnesium concentration on performance of Pacific white shrimp (Litopenaeus vannamei) cultured in low salinity water of West Alabama, USA

The ionic profile of inland low salinity water sources can be dramatically different with variable concentrations of magnesium (Mg2+). Inland shrimp farmers in Alabama, USA, supplement Mg2+ at the start of each production cycle to reach concentrations >20 mg/L at 1 to 11 g/L salinities. However, this concentration may not be high enough for larger shrimp in the later phase of the production cycle. Therefore, two field trials were conducted on a commercial shrimp farm in west Alabama to evaluate the effects of Mg2+ concentration in low salinity water on growth, survival, and physiology of Pacific white shrimp, Litopenaeus vannamei. In the first study, additional Mg2+ was supplemented to four production ponds (28 mg/L Mg2+) and compared with four control ponds (12.8 mg/L Mg2+). A stocking density of 27 post-larvae/m2 was used in ponds, and shrimp were offered a commercial feed twice daily. After a 23-week pond trial, whole-body Mg2+ concentrations were higher in shrimp reared in Mg2+ treated ponds, while no significant differences in other study variables were observed between pond groups. After week 15 (shrimp weight > 22 g), weekly body weights of shrimp were significantly lower in the control group compared to the elevated Mg2+ treatment. This could be due to size-dependent deficiency in the availability of adenosine triphosphate (ATP) and Mg2+ to support growth of larger adult shrimp. The second experiment was conducted to evaluate performance of larger shrimp (∼13 g initial weight) reared in two on-levee flow-through tank systems. One tank system received water from a control pond with 12 mg/L Mg2+, while the second system was sourced with water from a production pond with a higher amount of Mg2+ (37 mg/L). In each system, twelve 800 L tanks were stocked with shrimp at three different densities (24, 29, and 35 shrimp/m2) to evaluate possible interactions between stocking density and Mg2+ concentration in water. Following an 8-week tank trial, no significant effect of Mg2+ concentration, stocking density, or their interaction was observed on growth, survival, or physiology of shrimp. Overall, these results confirm that even moderate elevations in Mg2+ in low salinity water are advantageous to adult shrimp (>22 g) in later stages of the production cycle compared to post-larvae, juveniles, or sub-adult shrimp.

Taurine metabolism is modulated in Vibrio-infected Penaeus vannamei to shape shrimp antibacterial response and survival

BackgroundNumerous microorganisms are found in aquaculture ponds, including several pathogenic bacteria. Infection of cultured animals by these pathogens results in diseases and metabolic dysregulation. However, changes in the metabolic profiles that occur at different infection stages in the same ponds and how these metabolic changes can be modulated by exogenous metabolites in Penaeus vannamei remain unknown.ResultsHere, we collected gastrointestinal tract (GIT) samples from healthy, diseased, and moribund P. vannamei in the same aquaculture pond for histological, metabolic, and transcriptome profiling. We found that diseased and moribund shrimp with empty GITs and atrophied hepatopancreas were mainly infected with Vibrio parahaemolyticus and Vibrio harveyi. Although significant dysregulation of crucial metabolites and their enzymes were observed in diseased and moribund shrimps, diseased shrimp expressed high levels of taurine and taurine metabolism-related enzymes, while moribund shrimp expressed high levels of hypoxanthine and related metabolism enzymes. Moreover, a strong negative correlation was observed between taurine levels and the relative abundance of V. parahaemolyticus and V. harveyi. Besides, exogenous taurine enhanced shrimp survival against V. parahaemolyticus challenge by increasing the expression of key taurine metabolism enzymes, mainly, cysteine dioxygenase (CDO) and cysteine sulfinic acid decarboxylase (CSD).ConclusionsOur study revealed that taurine metabolism could be modulated by exogenous supplementation to improve crustacean immune response against pathogenic microbes.5E3vY5nuGW9ktCAisXY2AkVideo

The evaluation of ammonia tolerance in introduced and local Pacific white shrimp, Litopenaeus vannamei, populations in China

The white shrimp, Litopenaeus vannamei, is one of the most valuable commodities in the global seafood trade. Affected by high-density farming environments, ammonia accumulates in shrimp cultures and has a strong toxic effect, resulting in poor shrimp survival and poor immune function and metabolism. We selected six different populations of L. vannamei from Xing Hai No.1 (A and B), CHAI, Sy Aqua, PRIMO, and a second-generation Sy Aqua-PRIMO hybrid population (SP). The shrimps (3.24 ± 0.71 cm body length) were exposed to ammonia (24 h, 48 h), followed by recovery (R48 h, R96 h) to assess the tolerance of different populations. The survival rate (SR), immune-related enzymes (superoxide dismutase SOD, catalase CAT, and Glutathione peroxidase GSH-PX), Malondialdehyde (MDA), and metabolism (glutamate dehydrogenase GDH, glutamine synthetase GS, and aspartic acid transaminase GOT) and were measured at different populations under acute ammonia stress. Multiple comparisons of the ammonia resistance index from six populations showed that the expression of these indicators varied among the populations. The degree of lipid peroxidation in the Sy Aqua and PRIMO was significantly higher than in the other populations (P &lt; 0.05), and the ammonia metabolism index was poor. The GDH and GOT genes for the Xing Hai No.1 (A) were higher than for the other populations. Mortality and physiological indicators recovered to varying degrees for all experimental populations following 96 h of ammonia relief, whereas the Sy Aqua and PRIMO showed a noticeable lag. These results indicated that the immunity and metabolic capacity of Xing Hai No.1 (A) might be higher than those of Sy Aqua and PRIMO. These data could have value in developing future scientific breeding schemes and in the sustainability of shrimp farming.

Prevention of Vibriosis using whole cell microalgae on tiger shrimp hatcheries

In this study, a trial was conducted to use whole cell microalgae Porphyridium sp and Porphyridium aerugineum as an alternative material for preventing Vibriosis. This study used three treatments with three replications each. Treatment A was Control without microalgae administration, Treatment B was given Porphyridium aerugineum and treatment C was given Porphyridium sp. The microalgae were given in Zoea1, Mysis1, PL 2, PL 6, and PL 10 phases with the density of microalgae at the time of stocking was 105 - 106 cells/mL. Larval rearing was carried out for 19 days until Post Larva 12. The parameters observed were the density of microalgae in the rearing container and the density of Vibrio bacteria. Sampling for microalgae density observations was carried out every day from the zoea phase 2 to PL 10. Sampling of bacterial density was carried out at every phase change along with observing water quality parameters. At the end of the fry rearing period (PL 12), a challenge test was performed using V. parahaemolyticus bacteria with a density of 107 CFU/mL. Shrimp survival during the challenge test was observed every day until the fifth day. In addition, the density of Vibrio bacteria was also observed. The results showed that the administration of P. aerugineum could suppress the population of Vibrio bacteria and the ratio of Vibrio bacteria to common bacteria was better than the control. On the other hand, the highest survival rate for shrimp was treated with Porphyridium sp. After the challenge test, the best survival results were also obtained in the treatment with Porphyridium sp.

Test the effectiveness of Porphyridium aerugineum as Vibrio controller in shrimp ponds

Bacterial disease control in shrimp ponds was currently taking a more environmentally friendly approach. Thwas study aims to find out the effectiveness of Porphyridium aerugineum as a controller of Vibrioswas in ponds. This research was carried out at with two treatments with three replications. The first treatment was the administration of whole-cell microalgae P. aerugineum and the second treatment was control without microalgae administration. Tiger shrimp was stocked at the stadia PL 12 (density of 8 shrimp fry/m2). The study used 6 ponds measuring 10m x 25m with a water depth of 80cm. Microalgae was given once a week. A sampling of pond water and sediment was carried out once in two weeks. The results showed that the addition of wholecell microalgae P.aerugineum in ponds can reduce the ratio of total Vibrio bacteria and total plate count in ponds water but not in pond sediments. In ponds fed microalgae P.aerugineum, shrimp survival rate and production were higher than those of in controls. The results of thwas study showed that the adminwastration of microalgae as an additional supplement in ponds gave better results compared to the control.