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The immune mechanism elicited in pufferfish (Takifugu obscurus) against the invasion of Aeromonas hydrophila is still poorly understood. We examined the spleen of pufferfish at the transcriptome and proteome levels by using Illumina-seq and TMT coupled mass spectrometry after 12 h infection by A. hydrophila, respectively. A total of 2,339 genes (1,512 up-regulated and 827 down-regulated) and 537 (237 up-regulated and 300 down-regulated) proteins were identified. GO and KEGG analyses revealed that the responses to stimulus were the main biological processes, intestinal immune network for IgT production and calcium signaling pathway. Fourteen genes (8 up-regulated and 6 down-regulated) and proteins (5 up-regulated and 9 down-regulated) involved immune responses or signal transduction were validated by qRT-PCR and parallel reaction monitoring to confirm the reliability of the transcriptomic and proteomic analyses, respectively. Moreover, qRT-PCR and flow cytometry were used to detect dynamics of the genes in calcium signaling pathway and changes of concentration of cytoplasm Ca2+ in spleen cells within a 72 h challenge. This study provides the findings regarding immune response, especially intestinal immune network for IgT production pathway and calcium signaling pathway at the molecular, protein and cellular in pufferfish after infection by A. hydrophila. These results would provide a new insight and molecular targets into the response to pathogenic infection in pufferfish.

Different effects of a marine yeast strain Candida tropicalis HH8 and an aerobic denitrifying bacteria strain Pseudomonas stutzeri LZX301 on water properties especially nitrogen removal, biofloc formation and microbial communities were investigated. Both the strain HH8 and LZX301 removed inorganic nitrogen efficiently and participated biofloc formation. The combination use of the two strains is available in aquaculture due to their specific biochemical characteristics that much of nitrogen (44.87%) was converted to organic nitrogen by assimilation and bioflocs formed rapidly were more compact in the presence of the strain HH8 while much of nitrogen (59.33%) was removed by denitrification with the strain LZX301 added. Moreover, the phytoplankton stock (chlorophyll-a) was controlled at an appropriate level with the strain HH8 added. Microbial communities of biofloc varied largely and the relative abundance of Candida and Pseudomonas decreased obviously at the end of the trial. As a result, Candida tropicalis HH8 and Pseudomonas stutzeri LZX301 could be excellent participants in biofloc technology due to high-efficient nitrogen removal and fast-rate bioflocs formation.

An aerobic heterotrophic nitrogen removal bacterium strain, B1, was isolated from aquaculture water and identified as Pannonibacter phragmitetus (99% similarity) by 16S rRNA sequencing analysis. When ammonium, nitrite or nitrate was the sole nitrogen source, with an initial nitrogen concentration of 14 mg/L, the nitrogen removal efficiencies were 98.66%, 99.96% and 98.73%, respectively, and the corresponding maximum removal rates reached as high as 1.16, 0.77 and 0.81 mg/L/h, respectively. In the presence of NH4+-N, the removal efficiency of 56 mg/L NO2−-N within 27 h increased by 83.50%, and the corresponding removal rate reached as high as 1.72 mg/L/h. Additionally, different carbon sources ( dl -malic acid, sucrose, sodium citrate, and glucose) could be utilized in nitrogen removal. Sequence amplification indicates that the denitrification genes nirK, norB and narG are present in strain B1. All results demonstrate that strain B1 has high promise for future applications of removing inorganic nitrogen from wastewater.

Lectins are a group of carbohydrate-binding proteins, which play an important role in innate immune system against pathogen infection. In this study, a B-type mannose-binding lectin (OnBML) was identified from Nile tilapia (Oreochromis niloticus), and characterized at expression patterns against bacterial infection and capability to promote phagocytosis by macrophages. The open reading frame of OnBML is 354 bp of nucleotide sequence encoding polypeptides of 117 amino acids. The deduced protein is highly homologous to other teleost BMLs, containing two repeats of the conserved mannose-binding motif QXDXNXVXY. Expression of OnBML was widely exhibited in all examined tissues, with the most abundance in spleen and following gill, peripheral blood, and head kidney. The OnBML expressions were significantly up-regulated following two major bacterial infections including a Gram-positive bacterium (Streptococcus agalactiae) and a Gram-negative bacterium (Aeromonas hydrophila) in vivo and in vitro. Recombinant OnBML protein possessed capacities of mannose-binding and calcium-dependent agglutination to S. agalactiae and A. hydrophila, and promoted the phagocytosis by macrophages. Taken together, the present study indicated that OnBML is likely to get involved in host defense against bacterial infection in Nile tilapia.

The objective of this study was to document how different carbon sources affect the quality of biofloc (BF). The experiment consisted of three types of biofloc systems in which biofloc was produced by daily (25 days in all) supplementation with three different carbon sources, glucose (Glu), starch (Sta) and glycerol (Gly), in each 45-L tank; the C/N ratio was 15. The highest protein content was obtained in the BF (Glu), with a value of 41.2 ± 0.8% dry weight (DW). The BF (Sta) and BF (Gly) had lower values of 31.5 ± 0.6% and 35.5 ± 1.2% dry weight (DW). A higher lipid content was observed in the BF (Sta). The essential amino acid and nonessential amino acid contents were similar in BF (Glu) and BF (Gly), but both were higher than those of BF (Sta). The Essential Amino Acid Index (EAAI) for BF (Glu), BF (Sta) and BF (Gly) was 0.99, 0.93 and 0.98, respectively; which indicated that the biofloc produced in this experiment can be considered a good-quality protein source for shrimp. High-throughput sequencing of different bioflocs revealed that three types of bioflocs were dominant in Proteobacteria and Bacteroidetes. In addition, Cyanobacteria were the dominant biofloc in BF (Sta). Microscopic examination revealed that BF (Sta) was more closely related to the formation of the floc and contained more algae. Overall, this study demonstrated that bioflocs grown on different carbon sources have different qualities and suggested that the choice of carbon source used for growing bioflocs is of prime importance. Statement of relevance The present study indicated that different carbon sources could affect nutritional composition of biofloc, morphostructure of biofloc and the microbial community of biofloc. This result may provide a theoretical basis for the biofloc technology used in aquaculture.

To understand molecular responses of crustacean hepatopancreas to cold stress, we applied 2-DE proteomics approach to investigate altered proteins in the hepatopancreas of Litopenaeus vannamei during cold stress. At 13 °C for 24 h post cold stress, MALDI-TOF/TOF MS analysis revealed that 10 proteins of 13 spots showed significantly down-regulated during cold stress. Seven of them were enzymes, including chymotrypsin BI, preamylase 1, dimethylaniline monooxygenase, legumain, egumain-like, esterase D and adenosine kinase 2-like. Other three proteins identified to be down-regulated during cold stress in hepatopancreas are putative 40S ribosomal protein S12, proteasome subunit alpha type-5 and one hypothetical protein. 19 proteins of 24 significant up-regulated spots were observed in the hepatopancreas of cold-stress-treated shrimp, including crustacyanin-A, hemocyanin, fructose 1,6-bisphosphatase, malic enzyme, chitinase, glucose-regulated protein 78 and other 13 proteins whose functions during cold stress remain unclear. RT-PCR confirmed that the levels of transcription of the CBI, PA1, HC and CHI genes were found to relate well with that of its translation products after cold stress treated. The function of these proteins should be focused in the future studies. Further investigation of these data may lead to better understanding of the molecular responses of crustacean hepatopancreas to cold stress. Statement of relevance The purpose of this paper may lead to better understanding of the molecular responses of crustacean hepatopancreas to cold stress. The results provide important information on shrimp immune responses against cold stress.

Heterotrophic nitrification and aerobic denitrification (HN-AD), which is primarily performed by bacteria rather than fungi, is an attractive approach for nitrogen removal. In this study, a red yeast, Sporidiobolus pararoseus Y1, was isolated and shown to exhibit optimal growth and nitrogen removal efficiency on glucose, followed by citrate, sucrose, acetate and starch. The nitrogen removal efficiency increased with increasing initial concentrations of NH4+-N, NO2−-N and NO3−-N from 14 to 140 mg·L-1. At an initial nitrogen concentration of 140 mg·L-1, the maximum removal efficiencies of NH4+-N, NO2−-N and NO3−-N were 98.67%, 97.13% and 83.51% after 72 h incubation, while those of corresponding total nitrogen were 88.89%, 81.31% and 70.18%, respectively. The nitrification (amoA) and denitrification genes (nirK and napA) were amplified from Y1. These results suggest that yeast are also capable of HN-AD, which can be used to remove nitrogen in wastewater systems.

Biofloc technology (BFT) is an important application in aquaculture which based on conventional wastewater treatment systems. The most important part of BFT is biofloc (BF), which was made up of microbial community mostly. In this study, we explored the microbial communities in different bioflocs produced from three carbon sources (glucose, starch and glycerol), which were marked as BF (glu)、BF (sta) and BF (gly) respectively. These bioflocs were incubated for 25 days without animals. High-throughput sequencing was used to better understand microbial community composition and structure in BF. The results showed that Shannon diversity index was 5.83 ± 0.15 in BF (gly), 5.64 ± 0.07 in BF (glu) and 4.66 ± 0.35 in BF (sta). These meaned that there were more diverse microbial communities attached to and existed inside the BF(gly). A total of 15 different phyla and 30 families were observed. Phyla Proteobacteria and Bacteroidetes represented >70% of the total microbial for all bioflocs. Notably, Cyanobacteria phylum was most abundant in BF (sta), accounted for 29%, almost ten and forty times than BF (glu) and BF (gly). In addition, aquaculture pathogenic bacteria of Vibrio was absent in BF (sta). The reason why Vibrio was suppressed in BF (sta) remains unknown. Overall the study indicated that carbon source can significantly affect the microbial community composition、structure of biofloc and number of pathogens, suggesting that the choice of the carbon sources used in BFT is very important.

Water temperature is an important environmental factor in aquaculture farming that affects the survival and growth of organisms. The change in culture water temperature may not only modify various chemical and biological processes but also affect the status of fish populations. In previous studies, high temperature induced apoptosis and oxidative stress. However, the precise mechanism and the pathways that are activated in fish are still unclear. In the present study, we investigated the effects of high temperature (34°C) on the induction of apoptosis and oxidative stress in pufferfish (Takifugu obscurus) blood cells. The data showed that high temperature exposure increased oxygen species (ROS), cytoplasmic free-Ca(2+) concentration and cell apoptosis. To test the apoptotic pathway, the expression pattern of some key apoptotic related genes including P53, Bax, caspase 9 and caspase 3 were examined. The results showed that acute high temperature stress induced up-regulation of these genes, suggesting that the p53-Bax pathway and the caspase-dependent apoptotic pathway could be involved in apoptosis induced by high temperature stress. Furthermore, the gene expression of antioxidant enzymes (Cu/Zn-SOD, Mn-SOD, CAT, GPx, and GR) and heat shock proteins (HSP90 and HSP70) in the blood cells were induced by high temperature stress. Taken together, our results showed that high temperature-induced oxidative stress may cause pufferfish blood cells apoptosis, and cooperatively activated p53-Bax and caspase-dependent apoptotic pathway.

Ammonia is one of major environmental pollutants in the freshwater aquatic system that affects the survival and growth of organisms. In the present study, we investigated the effects of ammonia exposure on apoptosis, oxidative stress and immune response in pufferfish ( Takifugu obscurus ). Fish were exposed to various concentrations of ammonia (0, 1.43, 3.57, 7.14 mM) for 72 h. The date showed that ammonia exposure could induce intracellular reactive oxygen species (ROS), interrupt intracellular Ca 2+ (cf-Ca 2+ ) homeostasis, and subsequently lead to DNA damage and cell apoptosis. To test the apoptotic pathway, the expression patterns of some key apoptotic related genes including P53, Bax Bcl2, Caspase 9, Caspase 8 and Caspase 3 in the liver were examined. The results showed that ammonia stress could change these genes transcription, associated with increasing of cell apoptosis, suggesting that the P53–Bax–Bcl2 pathway and caspase-dependent apoptotic pathway could be involved in cell apoptosis induced by ammonia stress. In addition, ammonia stress could induced up-regulation of inflammatory cytokines (BAFF, TNF-α, IL-6 and IL-12) transcription, indicating that innate immune system play important roles in ammonia-induced toxicity in fish. Furthermore, the gene expressions of antioxidant enzymes (Mn-SOD, CAT, GPx, and GR) and heat shock proteins (HSP90 and HSP70) in the liver were induced by ammonia stress, suggesting that antioxidant system and heat shock proteins tried to protect cells from oxidative stress and apoptosis induced by ammonia stress. Our results will be helpful to understand the mechanism of aquatic toxicology induced by ammonia in fish.

Apoptosis plays a crucial role in many biological processes, including development, cellular homeostasis and immune responses. The BCL-2 family is a key regulator of the mitochondrial response to apoptotic signals in the intrinsic pathway. In this study, we identified and characterized the cDNA and expression pattern of pufferfish BCL-2 (PfBCL-2). The full-length cDNA of PfBCL-2 was 1412 bp with an open reading frame of 657 bp encoding a putative protein of 219 amino acids (Accession no: KP898414). The calculated molecular mass of the PfBCL-2 was 24.2 kDa with a predicted isoelectric point of 5.27. The deduced PfBCL-2 protein exhibited four highly conserved BCL-2 homology domains, suggesting that PfBCL-2 may play a similar role in the apoptotic-signaling pathway as in other species. Real-time PCR results showed that PfBCL-2 transcript was expressed in a wide range of tissues but exhibited the greatest level of expression in blood. Transcriptional responses of PfBCL-2 exhibited different spatial and temporal expression profiles in liver and blood after bacterial infection. PfBcl-2 transcript was significantly up-regulated in liver at 6, 12, 24 and 48 h (with maximum induction at 48 h) and was up-regulated in blood at 3, 6, 12 and 24 h (with maximum induction at 12 h). Meanwhile, recombinant PfBCL-2 fused with His6 tag was efficiently expressed in Escherichia coli BL21 (DE3) and purified using Ni-nitrilotriacetic acid resin. Western blot analysis indicated that its protein level appeared to be elevated during the initial bacterial infection. These results suggest that PfBCL-2 plays important roles in immune responses against bacteria challenge.

Phytases hydrolyze phytate to release inorganic phosphate, which decreases the requirement for phosphorus in fertilizers for crops and thus reduces environmental pollutants. This study analyzed microbial communities in rhizosphere sediment, collected in September 2012 from Shenzhen Bay, Guangdong, China, using high-throughput pyrosequencing; the results showed that the dominant taxonomic phyla were Chloroflexi, Firmicutes, and Proteobacteria, and the proportion of the beneficial bacteria, Bacillus, was 4.95 %. Twenty-nine culturable, phytase-producing bacteria were isolated, their phosphorus solubilization capacity was analyzed, and they were taxonomically characterized. Their phylogenetic placement was determined using 16S ribosomal RNA (rRNA) gene sequence analysis. The result shows that most of the isolates are members of the order Bacillales, although seven strains of Enterobacteriales, two strains of Pseudomonadales, and one strain of Oceanospirillales were also identified. The phytase gene was cloned from SPC09, Bacillus cereus, which showed the highest phosphorus solubilizing ability among the isolated strains. The gene encoded a primary translation product of 335 amino acids. A construct including the 1005-nt ORF fragment, Bc-phy, was transformed into Escherichia coli. The recombinant phytase was produced and purified, which revealed the temperature optima at 60 °C and pH optima at 6.5. The assessment by quantitative PCR (qPCR) showed an abundance of bacteria containing the Bc-phy gene; the level was generally higher in the mangrove forest than in the tidal flats and in surface soil compared to bottom soil, and the highest value was obtained in June. Herein, we report on the cloning, characterization, and activity of a novel phytase isolated from a mangrove system.

Waterborne ammonia has become a persistent pollutant of aquatic habitats. The exposure to ammonia stress can reduce growth in a wide range of aquatic organisms. To assess the effect of ammonia exposure on the growth hormone/insulin-like growth factors (GH/IGF) axis, we identified and characterized GHR1, GHR2 and IGF-1 from pufferfish. Comparative analysis showed that these genes shared high identity and similarity with corresponding genes in other fish species. The transcripts of these genes were widely expressed in all tested tissues. The highest level of GHR1 mRNA was found in the brain, whereas GHR2 and IGF-1 mRNA levels were the highest in the liver. Following acute ammonia exposure (100 mg/L total ammonia-nitrogen), GHR2 expression in the liver did not change at 6 h and then significantly decreased at 12, 24 and 48 h, whereas GHR1 and IGF-1 expressions were significantly down-regulated at 6, 12, 24 and 48 h, respectively. These results indicated that ammonia stress decreased the expression of GH/IGF axis genes, which might have negative effect on the growth and development of pufferfish.

Caspase-7 is a key effector caspase that takes part in apoptosis, inflammation, and in immune responses in mammals. To date, studies on the expression and functional characterization of caspase-7 upon apoptosis in teleosts are limited. Here, we identify a caspase-7 homolog (pfcasp-7) from pufferfish ( Takifugu obscurus ) and characterize its expression pattern during bacterial challenge. The open reading frame of pfcasp-7 is 942 base pairs in length, encoding a polypeptide of 313 amino acids. The deduced amino acid sequence is highly homologous to other known caspase-7 s, which contain a carboxyl-terminal catalytic domain and a pentapeptide active-site motif ( 192 QACRG 196 ). Quantitative real-time qPCR analysis indicated that pfcasp-7 is expressed in all examined tissues (kidney, blood, gills, gut, heart, spleen, liver, brain, and muscle), with the highest expression in the kidney (>117-fold higher than the lowest expression in muscle), followed by expression in the blood and gills. Challenging with Aeromonas hydrophila induced apoptosis in the blood and kidney and resulted in the significant upregulation of pfcasp-7 expression, which was consistent with the detection of apoptosis by flow cytometry. Pfcasp-7 expression was also upregulated in the kidney leukocytes following in vitro stimulation with lipopolysaccharide and inactivated A. hydrophila . Taken together, these results suggest that pfcasp-7 is involved in apoptosis in pufferfish after bacterial infection.

This study investigated the effect of continuous temperature decrease on hemocyte apoptosis of the white shrimp Litopenaeus vannamei. In the stress group, water temperature decreased from 26 to 17 °C at a rate of 1 °C/h. Shrimp kept at 26 ± 0.5 °C were used as control group. Total hemocyte count (THC), reactive oxygen species (ROS) production, cytoplasmic free-Ca2+ (CF-Ca2+) concentration, mitochondrial membrane potential (MMP), apoptotic cell ratio, and caspase-3 activity of L. vannamei hemocytes were determined when water temperature decreased to 23, 20, and 17 °C, respectively. Increased ROS production in hemocytes was observed when water temperature decreased to 20 and 17 °C. Decreased THC and cellular MMP, increased CF-Ca2+ concentration, apoptotic cell ratio, and caspase-3 activity were shown when water temperature decreased to 17 °C. These results indicate that water temperature decrease can induce oxidative stress on shrimp hemocytes and then cause mitochondria and caspase-3 mediated hemocyte apoptosis and THC reduction, when water temperature decreased to an unconformable level.

Apoptotic cell ratio and mRNA expression of caspase-3, cathepsin B (CTSB), heat shock protein 70 (HSP70), manganese superoxide dismutase (MnSOD), catalase (CAT), glutathione peroxidase (GPx) and thioredoxin (TRx) in hemocytes of white shrimp Litopenaeus vannamei exposed to nitrite-N (20 mg/L) was investigated at different stress time (0, 4, 8, 12, 24, 48 and 72 h). The apoptotic cell ratio and mRNA expression level of CTSB were significantly increased in shrimp exposed to nitrite-N for 48 and 72 h. Caspase-3 mRNA expression level significantly increased by 766.50% and 1811.16% for 24 and 48 h exposure, respectively. HSP70 expression level significantly increased at 8 and 72 h exposure. MnSOD mRNA expression in hemocytes up-regulated at 8 and 48 h, while CAT mRNA expression level increased at 24 and 48 h. GPx expression showed a trend that increased first and then decreased. Significant increases of GPx expression were observed at 8 and 12 h exposure. Expression level of TRx reached its highest level after 48 h exposure. These results suggest that nitrite exposure induces expression of apoptosis-related genes in hemocytes, and subsequently caused hemocyte apoptosis. Meanwhile, expression levels of HSP70 and antioxidant enzymes up-regulated to protect the hemocyte against nitrite stress.

Five feeding trials based on the isonitrogenous and isoenergetic experimental diets containing 34% protein, 6%, 8%, 10%, 12% or 14% lipid respectively in the circulating water culture system for both 30 and 60 days were conducted to investigate the effect of the dietary lipid level on the growth and immunity in white shirmp, Litopenaeus vannamei adults. The body weight and specific growth rate of white shrimp in different treatments indicated that shrimps fed the diet of 12% lipid level for 30d and 10% lipid level for 60d had the best developmental status. The ability of respiratory burst in hemocytes was improved as the increase of dietary lipid level. The transcripts of LGBP and pPO were sensitive to the dietary lipid in hemocyte and hepatopancreas respectively. The activities of CAT, GPx and AKP were increased to a certain extend according to dietary lipid level. Qualification of MDA showed the lowest level in the sample subjected to 12% lipid level diet, indicating an optimal utilization of the dietary lipid and an efficient clearance of MDA in vivo. These results suggested that dietary lipid level of 10–12% significantly tunes the growth and enhance the immune abilities mainly via ROS pathway of L. vannamei.

This study investigated the in vitro effects of nitrite on reactive oxygen species (ROS) production, NO production, esterase activity and cell apoptosis of Penaeus monodon haemocytes. Haemocytes were in vitro exposed to different dose of nitrite (0, 0.1, 0.5, 1, 5 and 10 μM). Cellular responses of nitrite-treated haemocytes were determined by flow cytometry. The results revealed that haemocytes treated by nitrite in vitro showed conspicuous time- and dose-dependent decreases in ROS and NO production as well as esterase activity. Additionally, 0.1 and 0.5 μM nitrite did not affect the apoptotic cell ratio during the 3h experimental time, while significant increases in apoptotic cells were observed after haemocyte exposure to nitrite at 1 μM for 3h, and at 5 or 10 μM for 1h. These results indicated that nitrite suppresses cellular functions, including production of ROS and NO, and activity of esterase. Cell apoptosis of haemocytes would be induced by extracellular nitrite as doses exceed 1 μM.

This study was aimed at investigating the cytotoxicity of nitrite on haemocytes of the black tiger shrimp, Penaeus monodon. Total haemocyte count (THC), reactive oxygen species (ROS) production, DNA damaged cell ratio and apoptotic cell ratio of shrimp were determined after exposure to different concentrations of nitrite-N (0, 1, 10 and 20 mg L−1) for 0, 6, 12, 24 and 48 h. There was no significant effect on the analytic indicator of shrimp exposed to 1 mg L−1 nitrite-N. THC decreased after 48 h exposure to 10 mg L−1 nitrite-N, and after 24 h exposure to 20 mg L−1 nitrite-N. Production of ROS was induced after 48 h exposure to 10 mg L−1 nitrite-N, and after 12 h exposure to 20 mg L−1 nitrite-N. The percentage of DNA damaged cell increased in P. monodon following 48 h exposure to 10 mg L−1 nitrite-N, and 24 h exposure to 20 mg L−1 nitrite-N. Apoptotic cell ratio increased after 48 h exposure to 10 mg L−1 nitrite-N, and 12 h exposure to 20 mg L−1 nitrite-N. These results indicated that nitrite-N would induce overproduction of ROS, and then resulted in DNA damage and cell apoptosis, and subsequently caused THC reduction. This process of oxidative stress was one of the toxicity mechanisms of nitrite on shrimp.

The cDNA encoding an extracellular copper zinc superoxide dismutase (LvECSOD) was cloned from the hepatopancreas of white shrimp Litopenaeus vannamei . It consisted of 915 bp nucleotides with an open reading frame corresponding to a deduced protein of 178 amino acids. The LvECSOD contains a putative signal peptide of 16 amino acids, two potential N-linked glycosylation sites (N 115 GTA and N 135 ITG) and a copper zinc superoxide dismutase family signature sequence (G 162 NAGaRvACctI 173 ). It was found that four copper binding sites, four zinc binding sites and two cysteines involving in the formation of the disulfide bridge were conserved in the protein. LvECSOD shared 33–58% identity to ECSODs from other organisms. Expression analysis revealed that LvECSOD mRNA was widely distributed in all the tissues examined. When the shrimp challenged with Vibrio alginolyticus or white spot syndrome virus (WSSV), expression of LvECSOD mRNA in the hepatopancreas and hemocytes was mediated responsively. Our results suggested that LvECSOD was implicated in the immune response induced by V. alginolyticus and WSSV.

White shrimp Litopenaeus vannamei Boone (6-7 cm) were individually exposed during 8 h to 0 (control), 0.5, 1.0, and 10.0 mg/l NO(2)(-)-N at 22 °C and 10 ‰ salinity. Nitrite concentration was measured, and hemolymph and hepatopancreas were sampled at 0, 4 and 8 h. Superoxide dismutase (SOD) activity, catalase (CAT) activity, and malondialdehyde (MDA) in haemolymph and hepatopancreas of L. vannamei Boone, and hemocyanin were examined. The results indicated significant relationships among hemocyanin concentration (Hc), nitrite concentration (nt), and exposure time (t) was as following: Hc = 1.250 + 0.0360 nt + 0.0636t, (R(2) = 0.702, P0.01), and Gompertz models with 3-parameters was used to describe well the increase trend of Hc with increase of nitrite concentration at 4, 8 h, respectively (R(2)0.99, P ≤ 0.05). MDA level and CAT activity in hemolymph decreased significantly at 8 h, and MDA level and CAT activity in hepatopancreas increased markedly. The SOD activity in hepatopancreas remained almost stably in the range of 0.22-0.24 U/g Hb within 8 h. The results showed there existed a immune difference between in hemolymph and hepatopancreas after white shrimp exposed to ambient nitrite within 8 h, and further experiments should be designed to answer the reason.