Role of myo-inositol supplementation against toxicity of excessive dietary copper in Pacific white shrimp Litopenaeus vannamei.

Raw materials for making dried shrimp (a type of foodstuff) are mostly from farmed shrimp and preliminary findings indicated that head copper (Cu) concentrations in some commercial dried shrimp products exceeded the safe limit specified in pollution-free aquatic products (50 mg/kg), which may influence food safety. Therefore, a 63-day feeding trial was conducted to explore effects of dietary Cu concentrations on accumulation of Cu in tissues, growth performance, immune response and antioxidant status of Pacific white shrimp (Litopenaeus vannamei). Moderating effect of myo-inositol (MI, adding 200 mg/kg diet) on the adverse impacts caused by excessive dietary Cu was also investigated. 600 shrimp (initial weight: 0.89 ± 0.00 g) were divided into five groups: 37.08 mg Cu/kg diet group (control group), 62.57 mg Cu/kg diet group, 125.99 mg Cu/kg diet group, 63.41 mg Cu/kg diet group (supplemented with MI) and 119.19 mg Cu/kg diet group (supplemented with MI). The results showed that dietary Cu concentrations increased from 37.08 to over 62.57 mg/kg, hepatopancreas Cu concentrations raised from 29.04 to 233.43-263.65 mg/kg, and muscle Cu concentrations only increased from 6.22 to 6.99-8.39 mg/kg. Report to control group, excessive Cu concentration (125.99 mg/kg) didn't significantly affect growth performance, but it notably reduced whole body lipid content and immune response, induced oxidative stress and damaged the hepatopancreas structure, which was ameliorated by MI supplementation. The results suggested that consuming shrimp head and its processed products weren't recommended. Cu concentrations of commercial feeds for Pacific white shrimp should be controlled below 62.57 mg/kg. Additionally, MI supplementation mitigated the negative impacts induced by excessive dietary Cu.

Acoustic particle motion detection in the snapping shrimp (Alpheus richardsoni).

Many crustaceans produce sounds that might be used in communication. However, little is known about sound detection in crustaceans, hindering our understanding of crustacean acoustic communication. Sound detection has been determined only for a few species, and for many species, it is unclear how sound is perceived: as particle motion or sound pressure. Snapping shrimp are amongst the loudest and most pervasive marine sound sources. They produce snaps during interactions with conspecifics, and they also interact with soniferous heterospecifics. If they can hear, then sound could facilitate key behavioral interactions. We measured the auditory sensitivity of the snapping shrimp, Alpheus richardsoni, using auditory evoked potentials in response to a shaker table that generated only particle motion and an underwater speaker that generated both particle motion and sound pressure. Auditory detection was most sensitive between 80 and 100 Hz, and auditory evoked potentials were detected up to 1500 Hz. Snapping shrimp responded to both the shaker table and the underwater speaker, demonstrating that they detect acoustic particle motion. Crushing the statocyst reduced or eliminated hearing sensitivity. We conclude that snapping shrimp detect acoustic particle motion using the statocyst, they might detect conspecifics and heterospecifics, and hearing could facilitate key behavioral interactions.

Dietary Supplementation of Brown Seaweed and/or Nucleotides Improved Shrimp Performance, Health Status and Cold-Tolerant Gene Expression of Juvenile Whiteleg Shrimp during the Winter Season.

This study was aimed to evaluate the efficiency of Sargassumpolycystum and nucleotides- supplemented diets to improve immune response and cold-tolerance of juvenile Litopenaeus vannamei. Four treatments were evaluated: T1, the control, shrimp received only a basal diet; T2, a basal diet with 500 ppm nucleotides; T3, a basal diet with 500 ppm S.polycystum powdered; T4, a basal diet with 500 ppm nucleotides and 500 ppm S.polycystum powdered. Shrimp were fed experimental diets for 56 days. Results revealed shrimp fed T4 diet exhibited the best significant improvement in water quality, survival, growth, and feed utilization indices followed by T2, and T3, while T1 showed the worst values. Additionally, nonspecific immune responses (phagocytosis (%), lysozyme, phenoloxidase, super oxide dismutase (SOD) activity, total nitric oxide) were improved with 1.7-3.2-fold in T4 higher than T1. Histomorphology of hepatopancreas in T4 showed the most increased activation of the hepatic glandular duct system compared with the other treatments. Moreover, nucleotides/seaweed-supplemented diets upregulated relative expression of cMnSOD, Penaeidin4, and heat shock protein70 (HSP70) genes, while translationally controlled tumor protein (TCTP) was downregulated. In conclusion, the synergistic effects of both S. polycystum and nucleotides have many advantages as a growth promoter, immunostimulant, antimicrobial, and cold-tolerant stimulant to L. vannamei.

Effects of dietary synbiotics supplementation methods on growth, intestinal health, non-specific immunity and disease resistance of Pacific white shrimp, Litopenaeus vannamei.

The present study aims to investigate the effects of dietary synbiotics supplementation methods on growth, feed utilization, hepatopancreas and intestinal histology, non-specific immunity and microbiota community of Pacific white shrimp (Litopenaeus vannamei). A control diet was designed to contain 18% fish meal (CON), and then 3 g kg-1 synbiotics (Bioture, consisting of Bacillus subtilis, Saccharomyces cerevisiae, ß-glucan and mannan oligosaccharide, etc) was supplemented to the control diet with three methods, directly adding in diets for pelleting (DAP), spraying diets after pelleting at once (SDA), spraying diets before feeding every day (SDE). Shrimp with initial body weight of 1.5 ± 0.12 g were fed one of the four diets for 56 days. The results showed that dietary synbiotics significantly increased the weight gain (WG), apparent digestibility coefficient (ADC) of crude protein (CP) and dry matter (DM), hepatopancreatic protease activity and decreased feed conversion ratio (FCR) (P < 0.05). Among the three synbiotics-added diets, SDE group showed the best growth with significantly higher WG than DAP group (P < 0.05). Serum activities of total superoxide dismutase, catalase, acid phosphatase, lysozyme and alkaline phosphatase of synbiotics-added groups were significantly higher, and serum malondialdehyde level was significantly lower than those of the control (P < 0.05). The intestinal villus width and villus number were also increased by the supplementation of synbiotics. The cumulative mortality was reduced in the three synbiotics-added groups after challenging with Vibrio parahaemolyticus (P < 0.05), and SDE group showed a significantly lower mortality than the control and DAP groups (P < 0.05). In intestinal microbiota composition, the abundance of Lactococcus tended to increase and Vibro tended to decreased in SDA and SDE groups. In conclusion, dietary synbiotics improved the growth, feed utilization, intestine health and non-specific immunity of Pacific white shrimp, and spraying synbiotics on diet presented better performance than adding synbiotics in diet for pelleting.

Reduction of spermatophore melanization in Litopenaeus vannamei shrimp fed Ulva clathrata during a commercial hatchery production.

Male broodstock (Litopenaeus vannamei, 36 ± 7 g, n = 600) reproductive performance, spermatophores and reproductive tract melanization, prostaglandin concentrations and biochemical composition were evaluated after including 3.8% Ulva clathrata meal in the diet (dry base) of a commercial hatchery during 45 days. Males fed Ulva had less melanized spermatophores (120 compared with 233, P < 0.01), less bacteria in the ductus deferens (P < 0.01), more sperm cells in testicles (P < 0.05), and increased courtship activity (839 compared with 689, P < 0.01), with no effect on mortality. Ulva-fed males had more arachidonic acid (20:4n-6) in the spermatophores (P < 0.05) but this did not affect the prostaglandin concentrations in response to diet. Males fed Ulva had more carotenoids in the hepatopancreas (0.08 ± 0.02 compared with 0.01 ± 0.01 mg/g, P < 0.05), and phenolic compounds in hepatopancreas (6.1 ± 0.7 compared with 1.8 ± 0.7 mg eq. phloroglucinol/g, P < 0.05) and muscle (0.4 ± 0.3 compared with 0.2 ± 0.1 mg eq. phloroglucinol/g, P < 0.05). Males fed the Ulva also had a lesser carbohydrate content in the hepatopancreas (P < 0.01) and muscle (P < 0.01). In conclusion, supplementing fresh maturation diets with a small dose of dried Ulva allowed for improvement of reproductive performance and to decrease melanization in spermatophores and the male reproductive tract.

Reproductive performance and vitellogenin mRNA transcript abundance in the hepatopancreas of female Litopenaeus vannamei fed diets with different soy lecithin content.

A 30-day nutritional study was conducted for determining the effects of supplementing soy lecithin (SL) in the diet of female Litopenaeus vannamei. Four isonitrogenous and isoenergetic diets were supplemented with graded amounts of SL including 0 (control), 20, 40 and 60 g Kg-1. The brooding specimens fed the 40 g SL/kg diet had the greatest gonadosomatic index (3.4 ±â€¯0.2 %) and the shortest latency period from eyestalk ablation to the first spawning (5 days). In addition, there was a larger content of long chain polyunsaturated fatty acids (LC-PUFA) in the hepatopancreas of brooding specimens fed with the 20 and 40 SL/kg diets compared to the other treatments. Furthermore, brooding specimens fed with the 40 g SL/kg diet had the greatest hemolymph cholesterol and high density lipoprotein concentrations. The abundance of vitellogenin mRNA transcript was greater in the hepatopancreas of brooding specimens fed with the 40 and 60 g SL/kg diets compared with the other groups. Results indicate that supplementing diets with 40 g SL/kg can improve growth and reproductive performance in L. vannamei female brooding specimens probably by enhancing LC-PUFA deposition and enhancing vitellogenin gene expression, as indicated by a greater abundance of mRNA transcript for vitellogenin, in the hepatopancreas.

Facile synthesis of haemocyanin-capped zinc oxide nanoparticles: Effect on growth performance, digestive-enzyme activity, and immune responses of Penaeus semisulcatus.

ZnO nanoparticles (NPs) synthesized using haemocyanin (Hc-ZnONPs) purified from haemolymph of Penaeus semisulcatus were characterized using various techniques. HR-TEM and SEM microscopy indicated Hc-ZnONPs had a typical size of 20-50 nm and were spherical. The objective of current investigation was to assess the effects of dietary supplementation of Hc-ZnONPs on the development and activity of digestive and metabolic enzymes, as well as the antioxidant levels in P. semisulcatus. Trial basal diets were supplemented with Hc-ZnONPs at rates of 0, 10, 20, 40, 60, and 80 mg kg-1 (dry feed weight) and were fed to P. semisulcatus for 30 d. For 60 mg kg-1 Hc-ZnONPs-supplemented feed, significantly (P < 0.05) enhanced endurance, development, and activity of the digestive enzyme were observed. The enzymatic antioxidants and metabolic enzymes activities in the muscle exhibited no significant changes when 10-60 mg kg-1 Hc-ZnONPs-supplemented feed was fed to P. semisulcatus. Conversely, feeding the P. semisulcatus with 80 mg kg-1 Hc-ZnONPs produced a harmful outcome, with significant increase in the enzymatic antioxidants and metabolic enzymes. Consequently, 80 mg kg-1 Hc-ZnONPs was identified as lethal to P. semisulcatus. Hence, it is proposed that the diet of P. semisulcatus can be supplemented with up to 60 mg kg-1 Hc-ZnONPs for improving the endurance, development and immunity.

Exposure to acute ammonia stress influences survival, immune response and antioxidant status of pacific white shrimp (Litopenaeus vannamei) pretreated with diverse levels of inositol.

The effect of acute ammonia challenge on survival, immune response and antioxidant status of Litopenaeus vannamei pretreated with diets containing different inositol levels was investigated. Shrimp (initial mean weight 0.40 ±â€¯0.00 g) were randomly allocated in 18 tanks (30 shrimp per tank) and triplicate tanks were fed with a control diet without myo-inositol (MI) supplementation (242.6 mg inositol kg-1 diet) or diets containing diverse levels of inositol (368.8, 459.7, 673.1, 993.8 and 1674.4  mg kg-1 diet) as treatment groups for 8-week. Randomly selected 10 shrimp per tank (final mean weight approximately 11.1-13.8g) were exposed to ammonia stress (total ammonia-nitrogen, 60.21  mg L-1) for 24 h after feeding trial. The results showed that after exposed to ammonia stress, survival rates of MI-supplemented groups were enhanced by 31-77% when compared with the control group. MI supplementation increased activities of alkaline phosphatase (AKP) and acid phosphatase (ACP) in plasma, and reduced its activities in hepatopancreas. It also enhanced activities of total antioxidant capacity (T-AOC), glutathione S-transferase (GST) and glutathione peroxidase (GPX) and content of reduced glutathione (GSH), and lowered malondialdehyde (MDA) and protein carbonyl (PC) content in plasma or hepatopancreas. In addition, mRNA expression levels of ferritin (FT), arginine kinase (AK), thioredoxin (Trx), heat shock protein 70 (Hsp70), catalase (CAT) and peroxiredoxin (Prx) were significantly differentially regulated in hepatopancreas owing to MI supplementation. Therefore, it suggested that L. vannamei pretreated with higher dietary inositol content may have better ammonia stress tolerance and antioxidant status after ammonia stress, and the optimum levels ranged from 459.7 to 993.8 mg inositol kg-1 when total ammonia-nitrogen concentration was 60.21  mg L-1.

The role of delta-1-pyrroline-5-carboxylate dehydrogenase (P5CDh) in the Pacific white shrimp (Litopenaeus vannamei) during biotic and abiotic stress.

Proline (Pro) metabolism is intimately associated with stress adaptation. The catabolism of Pro includes two dehydrogenation reactions catalyzed by proline dehydrogenase (ProDH) and Δ1-pyrroline-5-carboxylate dehydrogenase (P5CDh). P5CDh is a mitochondrial matrix NAD+-dependent dehydrogenase that is critical in preventing P5C-Pro intensive cycling and avoiding ROS production from electron run-off. Little is known about the roles of P5CDh in invertebrates, however. We cloned the P5CDh sequence in the Pacific white shrimp, Litopenaeus vannamei, and found that LvP5CDh is expressed predominantly in pleopod, hepatopancreas and gill. Subcellular localization analysis revealed that LvP5CDh protein was mainly found in the cytoplasm. In addition, overexpressing LvP5CDh in cells reduced ROS formation and inhibited apoptosis induced by LC50 Cd2+. Shrimp were exposed to various stress factors including infection with Vibrio alginolyticus, (½ LC50 and LC50) Cd2+, acid (pH 5.6) and alkali stress (pH 9.3). Both biotic and abiotic stress resulted in increased LvP5CDh expression and Pro accumulation; V. alginolyticus infection, pH 9.3 and LC50 Cd2+ stress apparently stimulated the Glu pathway of Pro synthesis, while pH 5.6 and ½ LC50 Cd2+ stress promoted the Orn pathway of Pro synthesis. Silencing of Lvp53 in shrimp attenuated LvP5CDh expression during Cd2+ stress, but had no effect on LvP5CDh mRNA levels if no Cd2+ stress was imposed. Our study contributes to the functional characterization of LvP5CDh in biotic and abiotic stress and reveals it to protect against ROS generation, damage to the cell, including the mitochondria, and apoptosis. Thus, LvP5CDh plays a critical role in immune defense and antioxidant responses.

Effects of dietary dosage forms of copper supplementation on growth, antioxidant capacity, innate immunity enzyme activities and gene expressions for juvenile Litopenaeus vannamei.

The experiment was conducted to evaluate the effects of different dietary dosage forms of copper supplementation on growth performance, hematological characteristics, antioxidant capacity, immune responses and gene expressions related to innate immune of juvenile Pacific white shrimp Litopenaeus vannamei. Three isonitrogenous and isolipidic diets were formulated to contain three dosage forms of copper: copper sulfate (Diet I-Cu), copper sulfate + copper amino acid complex (1: 1, Diet M-Cu) and copper amino acid complex from Availa®Cu100 (Diet Availa-Cu), respectively. 360 Pacific white shrimp juveniles (initial weight 1.86 ±â€¯0.03 g) were randomly allocated in 12 tanks corresponding to quadruplicate tanks of the three dietary treatments, and the 8-week feeding trail was conducted. The results indicated that percent weight gain (PWG) and specific growth rate (SGR) in shrimp fed M-Cu diet were significantly higher than that fed I-Cu diet. Survival, feed efficiency (FE), protein efficiency ratio (PER) of shrimp were not significantly different between all treatment groups. High contents of total protein (TP) and glucose (GLU) were found in shrimp fed the diet containing M-Cu, whereas contents of cholesterol (CHOL) and triacylglycerol (TAG) in shrimp fed M-Cu diet were significantly lower than that in I-Cu diet group. In hemolymph, shrimp fed M-Cu diet had high activities of phenoloxidase (PO), alkaline phosphatase (ALP) and acid phosphatase (ACP). While, Cu/Zn superoxide dismutase (Cu/Zn SOD), ceruloplasmin (CP) and lysozyme (LZM) in hemolymph were not significantly affected by different dietary dosage forms of copper. High activities of Cu/Zn SOD, ALP, ACP and LZM in hepatopancreas were observed in shrimp fed M-Cu diet. Shrimp fed diet supplemented with Availa-Cu showed a significantly higher gene expression levels of Cu/Zn sod, alp, acp and lzm in hepatopancreas than that fed I-Cu diet. This study indicated that copper amino acid complex was more effective than copper sulfate to improve growth performance and enhance antioxidant ability and innate immune system.

Fate of carotenoid-producing Bacillus aquimaris SH6 colour spores in shrimp gut and their dose-dependent probiotic activities.

Bacillus aquimaris SH6 spores produce carotenoids that are beneficial to white-leg shrimp (Litopenaeus vannamei) health. However, the optimal dose and mechanisms behind these effects are not well understood. We investigated the fate of SH6 spores in the gut of L. vannamei. Shrimp were divided into six groups administrated with either feed only (negative control) or SH6 spores at 5 × 106 CFU/g pellet (high dose, SH6 spore-H group), 1 × 106 CFU/g pellet (medium dose, SH6 spore-M group), 2 × 105 CFU/g pellet (low dose, SH6 spore-L group), astaxanthin at 0.5 mg/g pellet (Carophyll group), or carotenoids from SH6 vegetative cells at 5 µg/g pellet (SH6 carotenoid group). The growth rate was highest in SH6 spore-H (3.38%/day), followed by SH6 spore-M (2.84%/day) and SH6 spore-L (2.25%/day), which was significantly higher than the control (1.45%/day), Carophyll (1.53%/day) or SH6 carotenoid (1.57%/day) groups. The astaxanthin levels (1.9-2.0 µg/g shrimp) and red-colour scores (21-22) in SH6 spore-H/M were higher than the control (astaxanthin: 1.2 µg/g shrimp; red score: 20) or SH6 spore-L, but lower than the Carophyll and SH6 carotenoids. Feeding with medium and high doses of SH6 spores after 28 days resulted in respective 1.3-2-fold increases in phenol oxidase activity and 8-9 fold increases in Rho mRNA expression compared to the control and low dose group. The live-counts of SH6 in the gut gradually increased during the 28-day feeding period with SH6 spores at different concentrations, starting from 4.1, 8.2, and 5.4 × 104 CFU/g gut at day 1 and reaching 5.3, 5.1, and 4.4 × 105 CFU/g gut in the SH6-H/M/L groups, respectively, at day 28. Gut microbiota became more diversified, resulting in a 2-8-fold increase in total bacterial live-counts compared to the controls. SH6 spore germination was detected by measuring the mRNA expression of a specific sequence coding for SH6 amylase at 4 h, reaching saturation at 24 h. Our results confirm that SH6 spores colonize and germinate in the gut to improve the microbial diversity and boost the immune system of shrimp, exhibiting beneficial effects at >1 × 106 CFU/g pellet.

Predictive models for codend size selectivity for four commercially important species in the Mediterranean bottom trawl fishery in spring and summer: Effects of codend type and catch size.

Models to predict codend size selectivity for four major commercial species-European hake (Merluccius merluccius), Norway lobster (Nephrops norvegicus), deep-water rose shrimp (Parapenaeus longirostris), and Atlantic horse mackerel (Trachurus trachurus)-in Mediterranean bottom trawl fisheries were established based on data collected during fishing trials using the two legal codends: a 40 mm square-mesh codend and a 50 mm diamond-mesh codend. The models were applied to predict the extent to which size selection depend on codend type, also accounting for the potential effect of codend catch size and fishing season. The size selectivity of the two codends was evaluated and compared in identical simulated controlled conditions. Mesh type significantly affected the size selection of Norway lobster alone, with a slightly better performance of the 40 mm square-mesh codend. A high risk of retention of undersized individuals was predicted for both codends for all species except Norway lobster.

Dietary yeast hydrolysate and brewer's yeast supplementation could enhance growth performance, innate immunity capacity and ammonia nitrogen stress resistance ability of Pacific white shrimp (Litopenaeus vannamei).

An 8-week feeding trial was conducted to evaluate the effects of dietary yeast hydrolysate and brewer's yeast supplementation on growth, immune-related genes expression and ammonia nitrogen stress resistance of Pacific white shrimp (Litopenaeus vannamei). Three isonitrogenous and isolipidic practical diets were formulated to contain 0% (control diet), 1% yeast hydrolysate and 1% brewer's yeast, respectively. 360 juvenile L. vannamei with an initial weight (0.88 ±â€¯0.01 g) was randomly divided into 3 treatments in four replicates (30 shrimp per replicate). The results indicated that shrimp fed the diet containing 1% yeast hydrolysate had a significantly higher weight gain (WG), and specific growth rate (SGR) than that fed the control diet, and the lowest feed conversion ratio (FCR) was occurred in the 1% yeast hydrolysate supplementation group. Proximate composition in whole body and muscle among all treatments was not significantly influenced by the dietary yeast hydrolysate or brewer's yeast supplementation. The challenge test with ammonia nitrogen showed that lower cumulative survival was observed in those fed the control diet, and the highest cumulative survival was occurred at shrimp fed the 1% yeast hydrolysate supplementation. Shrimp fed the control diet had higher inflammation-related genes expression levels of tnf-α and il-1ß in the intestine than those fed the diets supplemented with 1% yeast hydrolysate or 1% brewer's yeast, however, there was no significant difference in expression level of alp in intestine among all treatments. The relative expression levels of mTOR signal pathway genes (eif4ebp, eif4e1a, eif4e2 and p70s6k) were significantly up-regulated in the shrimp fed the diets supplemented with 1% yeast hydrolysate, and the lowest gene expression levels of eif4ebp, eif4e1a, eif4e2 and p70s6k in the intestine were occurred at the control diet. The highest expression levels of the immune-related genes (dorsal, relish, and proPO) in the intestine were observed at shrimp fed the 1% yeast hydrolysate supplementation, and the lowest expression levels of these genes were occurred at shrimp fed the control diet, however, there was no significant difference in gene expression of lysozyme among all treatments. The expression levels of penaeidin3a, crustin, proPO, and IMD in the hepatopancreas were significantly influenced by the dietary yeast hydrolysate, brewer's yeast or no yeast product supplementation, shrimp fed the 1% yeast hydrolysate supplementation had higher expression levels of these genes than those fed the control diet. The present study indicated that dietary 1% yeast hydrolysate or brewer's yeast supplementation could improve growth performance, enhance innate immunity, and strengthen resistance of ammonia nitrogen stress, and dietary 1% yeast hydrolysate supplementation provides better immunostimulatory effects than brewer's yeast of L. vannamei.

Dietary supplementation of Haematococcus pluvialis improved the immune capacity and low salinity tolerance ability of post-larval white shrimp, Litopenaeus vannamei.

A 25-days experiment was conducted to evaluate the effect of dietary Haematococcus pluvialis on growth, survival, immune response and stress tolerance ability of post-larval Litopenaeus vannamei. Post-larval white shrimp (mean initial weight 2.1 mg) were fed five isoenergic and isonitrogenous diets containing grade levels of Haematococcus pluvialis (0, 1.7, 3.3, 6.7 and 13.3 g kg-1 diet, respectively). Results indicated that 3.3 g Haematococcus pluvialis kg-1 diet increased the survival rate of post-larval white shrimp. Specific growth rate (SGR) and weight gain (WG) showed no difference among each groups. After the acute salinity stress (salinity decreased rapidly from 28‰ to 5‰), survival of shrimp fed 6.7 g Haematococcus pluvialis kg-1 diet significant higher than the control (P < 0.05), and the total antioxidant capacity (T-AOC) was increased with the increasing dietary Haematococcus pluvialis levels. The malonaldehyde (MDA) contents in whole body decreased with the increasing dietary Haematococcus pluvialis levels before and after the salinity stress. Before the salinity stress, relative mRNA levels of Caspase 3, Rho and Janus kinase (JAK) decreased in shrimp fed diets contain Haematococcus pluvialis. After the salinity stress, relative mRNA levels of anti-oxidative related genes and immune related genes decreased with the dietary Haematococcus pluvialis level increased to 3.3 g kg-1. Based on the effect of Haematococcus pluvialis on survival, salinity stress tolerance ability and the immune response of post-larval L. vannamei, the optimal level of Haematococcus pluvialis was 3.3-6.7 g kg-1 diet (100-200 mg astaxanthin kg-1 diet).

The acute stresses role of the atypical 2-cys peroxiredoxin PmPrx5 in black tiger shrimp (Penaeus monodon) from biological immunity and environmental toxicity stress.

As a unique atypical 2-Cys Peroxiredoxin (Prx) of the Prx-like superfamily, Peroxiredoxin5 (Prx5) possesses special properties, such as its enzymatic mechanism, wide subcellular distribution and high affinity for peroxides and peroxynitrite. Prx5 plays a crucial role in oxidative stress, immune responses, cell apoptosis, proliferation, differentiation, intracellular signaling, the modulation of gene expression, ecdysis, etc. In this paper, we obtained a full-length Prx5 cDNA sequence (designated PmPrx5) from black tiger shrimp (P. monodon). The full-length PmPrx5 cDNA sequence was 1686 bp containing a 5' untranslated region (UTR) of 76 bp with two nucleotide sequences (AAA), a 3' UTR of 1040 bp with a poly (A) tail and two canonical polyadenylation signal sequences (AATAAA), and an open reading frame of 570 bp encoding 189 amino acid residues with a predicted molecular mass of 20 kDa and a theoretical isoelectric point of 6.29. Phylogenetic trees and multiple sequence alignment showed that the PmPrx5 had strong homology with Prx5 proteins from other species, such as similarity with Palaemon carinicauda (69%) and Macrobrachium rosenbergii (69%), containing the highly conserved functional domain. PmPrx5 mRNA was ubiquitously detected in all tested tissues. After P. monodon was exposed to pathogenic bacteria, osmotic pressure, acidity and alkalinity and the heavy metal, the mRNA expression of PmPrx5 in the gills and hepatopancreas was significantly enhanced (P < 0.01) because of the immune response and declined with heavy metal copper and cadmium challenges as time progressed. The recombinant PmPrx5 protein purified in E. coli (DE3) was further confirmed to exhibit antioxidant activity and antibacterial properties to a certain extent using a bacterial growth inhibition test in both liquid and solid cultures in vitro. E. coli transformed with pRSET-PmPrx5 were dramatically protected in response to metal toxicity stress. Thus, PmPrx5 may be developed as a potential therapeutic drug against pathogenic bacteria and as a biomarker for pollutant levels. This work offers useful clues to further explore the functional mechanism of Prx5 in marine shrimp immunity.

Dietary values of Forsythia suspensa extract in Penaeus monodon under normal rearing and Vibrio parahaemolyticus 3HP (VP3HP) challenge conditions: Effect on growth, intestinal barrier function, immune response and immune related gene expression.

Two trials were conducted to determine the effects of dietary Forsythia suspensa extract (FSE) on shrimp, Penaeus monodon, first on growth performance, second on the immune response and immune related gene expression of shrimp. In trial 1, shrimp (mean initial wet weight about 3.02 g) were fed with five diets containing 0% (basal diet), 0.01%, 0.02%, 0.04% and 0.06% FSE in triplicate for 60 days. Growth performance (final body wet weight, FBW; weight gain, WG; biomass gain, BG) of shrimp fed FSE diets were higher (P < 0.05) than that of shrimp fed the basal diet. The survival among all the diets treatments were above 90% and no significant difference was revealed among them (P > 0.05). The antioxidant capacity (total antioxidant status, TAS; glutathione peroxidase, GSH-Px) appears in the trend of firstly increasing then decreasing with the increasing of dietary FSE levels. The highest value of TAS and GSH-Px were found in shrimp fed 0.02% FSE diet and were significantly higher than that of shrimp fed the basal and 0.06% FSE diets (P < 0.05). Hepatopancreas malondialdehyde (MDA) of shrimp fed FSE diets were lower (P < 0.05) than that of shrimp fed the basal diet. Total haemocyte count of shrimp fed the basal diet was lower (P < 0.05) than that of shrimp fed FSE diets. Haemolymph clotting time of shrimp had the opposite trend with the total haemocyte count of shrimp. No significant differences were found in haemolymph biomarkers of intestinal permeability (endotoxin and diamine oxidase) and in molecular gene expression profiles of heat shock protein 70 (Hsp 70) mRNA and hypoxia inducible factor-1α (HIF-1α) mRNA in haemolymph of shrimp among all diet treatments (P > 0.05). In trial 2, a pathogenic strain of Vibrio parahaemolyticus 3HP (VP3HP) injection challenge test was conducted for 6-day after the rearing trial and shrimp survival were also compared among treatments. Survival of shrimp fed diets supplemented with 0.01%-0.02% FSE were higher than that of shrimp fed the basal and 0.06% FSE diets (P < 0.05). Dietary FSE supplementation produced stronger hepatopancreas antioxidant capacity (TAS, GSH-Px) (P < 0.05) and higher glutathione (GSH) level (P < 0.05), lower superoxide dismutase activity (SOD) (P < 0.05), higher total haemocyte count (P < 0.05), lower haemolymph clotting time (P < 0.05), lower MDA and carbonyl protein concentration (P < 0.05), lower haemolymph biomarkers of intestinal permeability (endotoxin and diamine oxidase) (P < 0.05), generated lower molecular gene expression profiles of HSP 70 mRNA and higher HIF-1α mRNA (P < 0.05) than the basal diet. The immune response were characterized by lower TAS and higher antioxidant enzyme activities (SOD, GSH-Px) and higher oxidative stress level (MDA and carbonyl protein) and higher haemolymph biomarkers of intestinal permeability (endotoxin and diamine oxidase) compared to levels found in trail 1. However, the total haemocyte counts and haemolymph clotting times were not changed in 0.01%-0.02% FSE diets treatments between trial 1 and trial 2 (P > 0.05). The molecular gene expression profile of Hsp 70 mRNA was increased while HIF-1α mRNA was decreased when compared to trial 1. In conclusion, results suggested that dietary intake containing FSE could enhance the growth performance and antioxidant capacity of P. monodon and furthermore reduce oxidative stress and immune depression challenged by a pathogenic strain of Vibrio parahaemolyticus stress. Considering the effect of FSE on both growth performance and immune response of P. monodon, the level of FSE supplemented in the diet should be between 0.01% and 0.02%.

Effects of glutathione on the survival, growth performance and non-specific immunity of white shrimps (Litopenaeus vannamei).

Reduced glutathione (GSH) is the most abundant non-enzymatic antioxidant present in mammalian cells and the main intracellular defence mechanism against oxidative stress. This study investigated the effects of GSH on survival rate, mean body gain weight, feed efficiency (FE), phenoloxidase (PO) activity, superoxide dismutase (SOD) activity, acid phosphatase (ACP), alkaline phosphatase (AKP) activity, GSH peroxidase (GPx) and susceptibility to Vibrio alginolyticus when Pacific white shrimps (Litopenaeus vannamei) were fed with GSH-containing diets. GSH was added to diets at 0.10, 0.20 and 0.30 g/kg during the eight-week breeding experiment. Oral administration of GSH had significantly increased mean body weight gain, FE, PO activity, SOD activity, ACP activity, AKP activity, GPx activity and susceptibility to V. alginolyticus compared with those of the control group (p < .05). Results indicate that GSH exerts both growth-promoting and immunostimulatory effects on Pacific white shrimps (L. vannamei).

Reduced glutathione supplementation in practical diet improves the growth, anti-oxidative capacity, disease resistance and gut morphology of shrimp Litopenaeus vannamei.

The present study was conducted to investigate the effects of reduced glutathione (GSH) supplementation in practical diet on growth performance, anti-oxidative response, disease resistance and intestine morphology of shrimp Litopenaeus vannamei. Two control diets based on the commercial formulation were designed with high level (27%) and low level (22%) of fish meal, respectively. Based on the control diet with low level of fish meal, 75, 150 and 225 mg/kg of GSH were added, respectively, to make the other three experimental diets. The five formulated diets were named as C1, C2, G1, G2 and G3, respectively. The shrimp (initial body weight: 0.30 ± 0.02 g) were fed with the five experimental diets for 8 weeks followed by a challenge test with Vibrio parahaemolyticus. The results showed that the specific growth rate (SGR) of shrimp in the C2 group was significantly lower than that in C1. The SGRs in G1 and G2 had no significant difference with those in C1 and C2. However, the SGR in G3 was significantly lower than that in C1. The serum GSH concentration in C2 was significantly lower than the other groups, but the malondialdehyde concentration was significantly higher. The supplementation of dietary GSH significantly improved the total anti-oxidative capacity and activities of glutathione S-transferase and glutathione peroxidase in serum. The villus height of intestine in the GSH supplemented groups had no significant difference with C1, but was significantly higher than C2. The jejunum wall thickness of intestine in G2 and G3 was significantly higher than those in the other groups. After the challenge test, the cumulative mortalities in G1 and G2 were significantly lower than C1 and C2. However, there was no significant difference in cumulative mortalities among G3, C1 and C2. In conclusion, based on the present experimental conditions, 75-150 mg/kg of GSH was suggested to be supplemented into the practical diet to improve the growth, anti-oxidative capacity, disease resistance and gut health of shrimp L. vannamei.

Monitoring of inland waters for culturing shrimp Litopenaeus vannamei: application of a method based on survival and chemical composition.

This study evaluated the suitability of 21 inland waters (16 well waters and 5 surface waters) from Northwest Mexico via short- (48 h) and medium-term (28 days) tests using postlarvae (PL18) of Litopenaeus vannamei. In the short test, survival was assessed at 48 h after shrimp were placed in groups of 10 postlarvae into 2-L containers of inland water, to which they had been previously acclimated. The second, medium-term test consisted of four replicates with 10 postlarvae, and each group was placed in 15-L containers with the treatment water. Weights (initial and final) and survival were evaluated weekly for 28 days. In those waters for which the short test was positive and the medium-term test was negative and which also had a deficiency of potassium and/or magnesium, a third test was conducted. These last waters were supplemented with salts, and the shrimp survival and weights (initial and final) were recorded for 28 days. The water samples from San Jose, Mochicahui, Sinaloa River, Caimanero inner Lagoon, La Pipima, Campo Santa Fe, Escopama, and Fitmar had >60% survival in the short test. The Caimanero inner Lagoon water had the highest survival (87.5 ± 9.6%) and final mean weight (201.3 ± 86.2 mg). In the third test, it was found that shrimp in the water from La Pipima, Campo Santa Fe, and Fitmar exhibited 100% survival for 2 weeks. Finally, in this work, a decision tree to evaluate the suitability of low-salinity water for shrimp farming was proposed, which can be applied in other regions.

Antibacterial function of herbal extracts on growth, survival and immunoprotection in the black tiger shrimp Penaeus monodon.

This study examined the effects of an herbal extract composed of nine herbs i.e Aloe vera, Andrographis pariculata, Annona squamosa, Azadirachta indica, Citrus aurantifolia, Coriandrum sativum, Ocimum sanctum, Ollium cepa and Psidium guajava on growth, survival rate and immunoprotection against pathogenic Vibrio harveyi in the tiger shrimp Penaeus monodon. The petroleum ether, methanol and N-hexen extracts of different herbal plants were selected, processed and thoroughly mixed in equal proportions and added to the shrimp diets at a concentration of 1.0, 2.5 and 5.0 mL kg-1. After 60 days of feeding, shrimps were challenged with V. harveyi bacteria (1 × 107 cells mL-1), which were isolated and propagated from the infected shrimps. The shrimps fed on diets with methanolic extraction of 2.5 mL kg-1 had significantly (P < 0.001) higher survival rate (76%), specific growth rate (4.26 ± 0.11%) and better food conversion ratio (1.5) than the other groups. This study indicates that addition of methanolic herbal extracts of 2.5 mL kg-1 can positively influence the immune response of tiger shrimp against V. harveyi infection.