Activities Of Immune-related Enzymes Research Articles

Effects of the Probiotic Psychrobacter sp. B6 on the Growth, Digestive Enzymes, Antioxidant Capacity, Immunity, and Resistance of Exopalaemon carinicauda to Aeromonas hydrophila.

Probiotics, known to improve the water quality and the host's intestinal microbial balance, has gained more and more attention in recent years. The effects of Psychrobacter sp. B6 on the growth and immunity of Exopalaemon carinicauda were investigated in this study. Psychrobacter sp. B6 was sprayed to the basal diet with four different levels (0 [basal diet], 5 × 105, 5 × 107, and 5 × 109CFU/100g diet) and were fed to E. carinicauda (average weight 1.15 ± 0.04g) for 30days. At the end of the feeding trial, shrimps were immersed in seawater contaminated with 106CFU/mL pathogenic Aeromonas hydrophila for 2h and then the cumulative mortality was calculated after 14days observation. The results showed that the weight gain rate, survival rate, and specific growth rate of E. carinicauda were significantly increased with the increasing dietary level of Psychrobacter sp. B6. The activities of digestive enzymes (α-amylase and chymotrypsin) were significantly increased (P < 0.05) in the groups fed with Psychrobacter sp. B6, and the highest activities of digestive enzymes were detected in the 5 × 109CFU/100g diet group. The activities of antioxidant enzymes (catalase, peroxidase, and superoxide dismutase) in probiotics treated shrimp were significantly higher than those in the control shrimp, with the highest activity in 5 × 109 and 5 × 107CFU/100g diet group separately. At the same time, the activities of immune-related enzymes (alkaline phosphatase and lysozyme) were significantly affected by the dietary B6 content, and the highest activity of immune-related enzymes was found in shrimps fed with 5 × 107CFU/100g diet. The relative expression levels of CTL (C-type lectin), MBL (mannose-binding lectin), SPI (serine protease inhibitor), and ProPo (prophenoloxidase) in hepatopancreas of E. carinicauda with 5 × 109CFU/100g diet were significantly higher than those in the control. Moreover, cumulative mortality (22.22%) post-challenge with A. hydrophila was the lowest in 5 × 109CFU/100g diet. The results suggested that Psychrobacter sp. B6 could effectively promote the growth, immunity, antioxidant capacity, and disease resistance of E. carinicauda. This study provided a reference for the study on the artificial breeding of E. carinicauda.

Dietary Haematococcus pluvialis promotes growth of red swamp crayfish Procambarus clarkii (Girard, 1852) via positive regulation of the gut microbial co-occurrence network

Plant protein served as an alternative protein source to fish meal is widely used in the feed of Procambarus clarkii, but its excessive use has adverse impacts on aquatic animals. Haematococcus pluvialis has great potential for food applications due to its abundant astaxanthin. This experiment investigated the effects of dietary H. pluvialis on growth performance and gut microbiota of P. clarkii. That dietary H. pluvialis significantly increased weight gain rate (WGR), specific growth rate (SGR), and haemolymph immune-related enzyme activities was presented (P < 0.05), accompanied by a decrease in malondialdehyde (MDA) content. Moreover, dietary H. pluvialis reversed microbial dysbiosis and gut immune damage due to the decreased abundance of operational taxonomic unit (OTU) (s__Bacteroidaceae_bacterium_MS4), where interactions within the co-occurrence network restored gut villus development and microbial community stability. Thus, 0.6% H. pluvialis powder was recommended to be included in the feed. It was initially revealed that dietary H. pluvialis helped to stabilize microbial homeostasis, providing a scientific basis for the development of a functional feed.

Effects of Dietary Phaffia rhodozyma Astaxanthin on Growth Performance, Carotenoid Analysis, Biochemical and Immune-Physiological Parameters, Intestinal Microbiota, and Disease Resistance in Penaeus monodon.

The present study aimed to investigate the effect of dietary astaxanthin (Ast) from Phaffia rhodozyma on growth performance, survival, carotenoid content, the activity of antioxidant and immune-related enzymes, intestinal microbiota comparison, and disease resistance against Vibrio parahaemolyticus in Penaeus monodon. Juveniles (average weight 3.15 ± 0.12 g) were fed with six experimental diets supplemented with 0 (Control), 20.5, 41, 61.5, 82, and 102.5 mg/kg of Ast (defined as diet A–D) in triplicate for 56 days. The results indicated that shrimp fed with Ast supplementation significantly (p < 0.05) improved growth performance compared with the control. Furthermore, significantly (p < 0.05) increased survival and decreased feed conversion ratio (FCR) demonstrated the beneficial effects of dietary Ast on enhancing nutrient utilization and ultimately improving the growth and survival of shrimp. Furthermore, shrimp fed with Ast including diet developed a deeper red color than the control, consistent with the significantly (p < 0.05) increased Ast deposition in the shrimp shell. Hemolymph-immunological parameters [aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (AKP)] and hepatopancreatic antioxidant status [total antioxidant capacity (T-AOC), malondialdehyde (MDA), catalase (CAT), and superoxide dismutase (SOD)] were significantly (p < 0.05) affected by dietary Ast supplementation. Dietary increasing Ast levels significantly (p < 0.05) increased shrimp resistance performance to V. parahaemolyticus according to the LT50 results in the current study, which may be caused by increased total carotenoid contents in shrimp tissues from all the Ast-supplemented treatments. Conversely, intestinal microbiota biodiversity and richness were not affected by dietary Ast. The best performances of growth, antioxidant status, immunological response, and carotenoid deposition were observed in diets E and F among all the Ast-supplemented treatments. Overall, all the data suggested that dietary P. rhodozyma Ast played a critical role in improving growth performance, achieving the desired coloration, increasing carotenoid content, and keeping better health status of shrimp. Based on these positive performances, P. rhodozyma Ast could gain the trust of the consumers as a natural source and provide a potential alternative for synthetic Ast using in the Penaeus monodon culture industry.

Effect of infection with Aeromonas hydrophila on antioxidant capacity, inflammation response, and apoptosis proteins in Chinese mitten crab (Eriocheir sinensis)

Aeromonas hydrophila (A. hydrophila) as a serious bacterial disease endangering aquaculture and the Chinese mitten crabs (Eriocheir sinensis) industry. The present study was conducted to investigate the effects of A. hydrophila on the antioxidant, inflammation, immunity and apoptosis of the E. sinensis. The E. sinensis (female: 150 crabs and male: 150 crabs; 67.11 ± 0.76 g) were randomly divided into the control group (Foot injection with 200 μl PBS) and infection group (Foot injection with 200 μl A. hydrophila of 106 cfu/mL). The hepatopancreas and serum was collected to detect the related indicators after injection 24 h. The results showed that A. hydrophila significantly reduced the malondialdehyde (MDA) level and gamma-glutamyl-cysteine synthetase (γ-GCS) activity in the hepatopancreas of male and female crabs (P < 0.05). A.hydrophila also significantly decreased the total-superoxide dismutase (T-SOD) activity while the levels of total antioxidant capacity (T-AOC) and total glutathione (T-GSH) were significantly increased in the hepatopancreas and serum of male crabs (P < 0.05). At the transcriptional level, the expression of catalase (CAT) and glutathione peroxidases (GPx), Glutathione S-transferase (GST) in the hepatopancreas of male and female crabs was significantly reduced compared to the control group (P < 0.05). However, A. hydrophila could not significantly change the Kelch-like ECH-associated protein 1 (Keap1) gene expression level in both of male and female carbs. A. hydrophila injection for 24 h, the lysozyme (LZM) and phenoloxidase (PO) activity was significantly increased in the hepatopancreas and serum of the male and female crabs (P < 0.05). Simultaneous increase of immune-related enzyme activity (acid phosphatase and alkaline phosphatase) was found in the serum of male and female crabs (P < 0.05). However, the acid phosphatase (ACP) and alkaline phosphatase (ALP) activity was significantly decreased in the hepatopancreas of male and female crabs (P < 0.05). Meanwhile, the LZM mRNA level was significantly decreased in the hepatopancreas of E. sinensis (P < 0.05). Furthermore, A. hydrophila significantly inhibited the mRNA expression of immune regulated factors (Interleukin enhancer binding factor 2: ILF2, interleukin-16: IL-16, Toll-like receptor: TLR) in the male and female crabs. The levels of inflammatory cytokines (interleukin-1β: IL-1β, interleukin-6: IL-6, interleukin-8: IL-8, interleukin-10: IL-10) were significantly increased in the hepatopancreas of male and female crabs. Moreover, A.hydrophila increased the mRNA expression of apoptosis - related genes in male crabs (p38 mitogen-activated protein kinase: p38, adamalysin 17: ADAM17, Cysteine-aspartic acid protease 3: Caspase 3, and Bcl-2-associated X: BAX), but reduced the expression of p38, ADAM17, Caspase 3 and BAX genes in female crabs. In conclusion, A. hydrophila could induce oxidative stress and the response of inflammation and immunity, and also trigger the mRNA expression changes of apoptosis related-genes in E. sinensis. This study provides a theoretical basis for the study of E. sinensis diseases.

An evaluation on the selenium yeast supplementation in the practical diets of early juvenile sea cucumber ( Apostichopus japonicus ): Growth performance, digestive enzyme activities, immune and antioxidant capacity, and body composition

A 45-day feeding trial was carried out to investigate the effects of dietary selenium yeast (Se-yeast) on the survival, growth performance, activities of digestive enzymes and antioxidant enzymes, and body composition of early juvenile Apostichopus japonicus. Five isoprotic (15.6%) and isolipic (1.5%) feeds with graded levels of Se-yeast (0, 0.5, 1.0, 1.5 and 2.0 mg/kg) were formulated and randomly allocated to the early juvenile sea cucumbers (initial weight: 0.11 ± 0.01 g). The results showed that the weight gain rate (WGR) and relative visceral weight ratio (RVW) significantly increased as the Se-yeast supplementation increased from 0 to 1.0 mg/kg, and then reached a plateau with further increase in Se-yeast, while survival rate (SR) increased as the supplementation level of Se-yeast increased, and the lipase and amylase activities first significantly increased as the Se-yeast increased from 0 to 1.0 mg/kg, and then significantly decreased with the continuous supplementation of Se-yeast. The antioxidant capacity and nonspecific immunity were significantly elevated by the moderate level (0.5 and 1.0 mg/kg) of Se-yeast. Besides, the activities of immune-related enzymes and transcription of antioxidation-related genes were significantly elevated by the supplementation of Se-yeast. However, malonaldehyde contents were significantly reduced in the treatments with 0.5 and 1.0 mg/kg Se-yeast. The selenium content in the body wall of the sea cucumber showed a markedly increasing trend with increasing Se-yeast supplementation levels. Results above indicated that a moderate level (0.5–1.0 mg/kg) of Se-yeast enhanced the growth performance, digestive enzyme activities, antioxidant capacity and nonspecific immunity of early juvenile A. japonicus.

The related immunity responses of red swamp crayfish (Procambarus clarkii) following infection with Aeromonas veronii

Aeromonas veronii is a typically opportunistic pathogen of aquatic animals as well as human beings, and it was one of the main pathogenic factors for septicemia in aquatic animals. In our previous study, a virulent strain of A.veronii was isolated from naturally infected crayfish Procambarus clarkii, which could cause serious disease for healthy crayfish. In this study, to determine the immune response of P. clarkii to the isolated A. veronii, the histopathology, the total hemocyte count (THC), the activities of immune-related enzymes, and the expression profiles of immune-related genes were evaluated. The results showed that the hepatopancreas, intestine, and gills of crayfish exhibited obvious tissue damage after being infected with A.veronii. The THC was dramatically reduced in the hemolymph of crayfish after being infected with A.veronii, which suggested that the immune system of P. clarkii was seriously damaged. Compared to the control group, the activities of acid phosphatase (ACP), alkaline phosphatase (AKP), phenoloxidase (PO), and lysozyme (LYZ) in the hemocytes, hemolymph, and hepatopancreas, and gills were increased in the A. veronii-infected crayfish after some time points. Additionally, upon A.veronii infection, the mRNA expression levels of eight immune-related genes including hemocyanin, lysozyme, anti-lipopolysaccharide factor 3, peroxiredoxin 6, prophenoloxidase, C-type lectin, astacidin, and Rab7 showed significant changes, respectively, in hepatopancreas, intestine, and gills. Our data demonstrated that the A. veronii could trigger a comprehensive innate immune response in P. clarkii. Our results could provide a theoretical foundation for better understanding the non-specific immunity of P. clarkii to A.veronii infection.

Effects of dietary Lactobacillus acidophilus and tussah immunoreactive substances supplementation on physiological and immune characteristics of sea cucumber (Apostichopus japonicus)

To investigate the effects of Lactobacillus acidophilus and tussah immunoreactive substances (TIS) supplementation alone or together on the growth performance, digestive and immune-related enzyme activities, and intestinal microbiota of the sea cucumber Apostichopus japonicus, a feeding experiment was conducted. The supplementation of L. acidophilus and TIS together produced the maximum digestive and immune activities, while the minimum values occurred in the control group. No remarkable differences in enzyme activities were observed when supplemented individually. Dietary L. acidophilus and TIS in combination might be more capable of improving digestive capacity, food utilization rate, phosphatase-responsiveness and antioxidants. Furthermore, the supplementation of L. acidophilus and TIS in combination demonstrated a greater ability to optimize the intestinal microbiota of A. japonicus by increasing the potentially beneficial bacteria involved in energy production and biosynthesis, and suppressing the opportunistic pathogens. These results collectively indicated that the combined supplementation of L. acidophilus and TIS has a synergistic effect on enhancing immunity and digestibility, and could improve the intestinal microbiota structure of A. japonicus, suggesting potential for industrial feeding applications.

Immune and intestinal microbiota responses to aerial exposure stress in Chinese mitten crab (Eriocheir sinensis)

Desiccation is an important environmental stressor during crabs culture and transportation. In this study, we investigated oxidative damage, antioxidant capacity, immune-related enzyme activity and intestinal microbiota responses of Eriocheir sinensis subjected to aerial exposure stress for 96 h. The results revealed a significant increase in lipid peroxide (LPO) and malondialdehyde (MDA) levels in the hepatopancreas after aerial exposure (p < 0.05). Antioxidant activities including superoxide dismutase (SOD) and total antioxidant capacity (T-AOC) showed significant variations (p < 0.05). Alkaline phosphatase (AKP) and acid phosphatase (ACP) activity both increased to the maximum levels at 12 h, and were significantly lower than those of controls at 72 h and 96 h respectively (p < 0.05). High-throughput 16S ribosomal DNA (rDNA) sequencing revealed that aerial exposure stress altered bacterial diversity, and changed the composition of intestinal microbes. Specifically, abundance of beneficial bacteria Citrobacter decreased, while abundance of pathogenic bacteria Acinetobacter increased. The results revealed that prolonged period of air exposure stress adversely affects the antioxidant status, immune function, and intestinal flora in E. sinensis. This work could help to uncover the mechanisms of aerial exposure stress responses in this species.

A diet rich in diatom improves the antibacterial capacity of Pacific oyster Crassostrea gigas by enhancing norepinephrine-regulated immunomodulation

Microalgae such as dinoflagellate and diatom are the major food source of bivalve species, and sufficient food intake contributes to the immunity and the growth of bivalves. In the present study, a monoamine oxidase gene (named as CgMAO), which is the rate-limiting enzyme of norepinephrine (NE) biosynthesis, was cloned from C. gigas. After the oysters were fed with a diet rich in diatom for 21 and 40 d, the NE contents in oyster serum, as well as the mRNA expression of CgMAO in oyster haemocytes, increased significantly compared with control group. Besides, the mRNA expression of cytokines CgTNF-1 and CgIL17-5 in haemocytes and the activities of immune-related enzymes (SOD and LYZ) in oyster serum also increased significantly after diatom feeding. These results collectively suggested that sufficient microalgae intake might significantly enhance the antibacterial capacity in oyster by prompting the biosynthesis of NE and triggering the subsequent antibacterial processes modulated by NE.

Comparative splenic proteomic analysis of susceptible and resistant GIFT tilapia following challenge with Streptococcus agalactiae

Nile tilapia is an important economically farmed fish worldwide, and Streptococcus agalactiae has become the most serious disease problem for the tilapia industry in China. Therefore, a better understanding of the innate immune mechanisms and their functions in the context of pathogen invasion is needed. In this study, a high-throughput proteomic strategy was developed for determining the differential expression proteins (DEPs) of the genetically improved farmed tilapia (GIFT) (susceptible and resistant GIFT species) splenic responses to S. agalactiae infection. The results showed 1608 proteins were identified with high confidence (P < 0.05). A total of 441 and 382 DEPs were characterized in susceptible and resistant GIFT tilapia species, respectively. Gene ontology (GO) annotation showed that the DEPs covered many biological functions, including cellular process, metabolism, and immune process. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis indicated that the DEPs were mainly enriched in the lysosome, apoptosis, and complement and coagulation cascade pathways during S. agalactiae infection. By group comparisons, the proteins related to immune response, cytoskeleton, and energy metabolism of disease-resistant strains were upregulated compared with those of susceptible strain. The content determination of immune-related enzyme activity was consistent with the results obtained throughout the study. More active innate immune system and cell defense is the basis of S. agalactiae resistance for disease-resistant GIFT tilapia species. Furthermore, 34 proteins involved in disease resistance were characterized. Therefore, the present study contributes to a better understanding of the immune system and defense mechanisms of GIFT tilapia in response to S. agalactiae infection and provides valuable recommendations for breeding disease-resistant GIFT tilapia species.

The role of trans-vp28 gene Synechocystis sp. PCC6803 in the defense against white spot syndrome virus (WSSV)

To develop a more comprehensive understanding of the efficacy of trans-vp28 gene Synechocystis sp. PCC6803 and its effect on white spot syndrome virus (WSSV), this study investigated the activities of several immune-related enzymes including acid phosphatase (ACP), alkaline phosphatase (AKP) and peroxidase (POD) in muscle and hepatopancreas of Penaeus vannamei, and conducted a more intuitive analysis from the perspective of histopathology. P. vannamei were orally fed trans-vp28 gene Synechocystis sp. PCC6803 for 10 days and then challenged with WSSV. The cumulative survival rate, activities of enzymes and the histopathology were determined. The results show that on the 7th day after challenge, the survival rate of the experimental group (i.e., challenged and fed mutant Synechocystis sp. cells) and the wild type group (i.e., challenged and fed wild type Synechocystis sp. cells) were 80.2% and 26.4%, respectively, while all shrimp in the positive control group (i.e., challenged, but no vaccination) died. There was no death in the negative control group (i.e., no vaccination or challenge). After immunization, the activities of ACP, AKP and POD in both tissues were the highest in the experimental group. After challenge, the final enzyme activities of the three enzymes in the experimental group were higher than those in the positive control group and the wild type group. The results of histopathology showed that muscle fibers in the negative control group were neatly arranged with numerous and evenly distributed nuclei, while muscle fibers in the positive control group and the wild type group were wavy. The nuclei of muscle fibers in the positive control group were also swollen and unevenly distributed. The nuclei of the muscle fibers in the experimental group were slightly clustered, and the muscle fibers were arranged neatly. In hepatopancreas samples, narrow cell gaps and regular nuclei were observed in the negative control group. The connective tissue and cell walls were severely damaged and the cells were degraded in the positive control group. However, although the connective tissue of the experimental group was slightly loose, the cells were orderly and the nuclei were arranged neatly. These results indicated that trans-vp28 gene Synechocystis sp. PCC6803 could improve the immunity of shrimp.

Dietary administration of Pleurotus ostreatus polysaccharides (POPS) modulates the non-specific immune response and gut microbiota diversity of Apostichopus japonicus

Pleurotus ostreatus polysaccharides (POPS) can modulate the growth, immune response, and anti-inflammatory and antioxidant properties of mammals and aquatic animals. However, there has been no report about the effect of POPS on the innate immunity, growth and gut microbiota of A. japonicus to date. Here, we explored the relationship between dietary administration of POPS and the innate immunity or gut microbiota of A. japonicus. The results showed that after dietary administration of POPS, although there was no significant effect on the visceral wall ratio, weight gain or specific growth rate of A. japonicus, the activity of antioxidant and immune-related enzymes changed in A. japonicus. Moreover, there were differences in gut microbial diversity at multiple taxonomic levels in A. japonicus receiving dietary POPS supplementation. The dominant populations of gut microbiota in A. japonicus were Proteobacteria and Bacteroidetes at the phylum level. Interestingly, after dietary POPS supplementation, the relative abundance of Proteobacteria was reduced, while the relative abundance of Chloroflexi was increased. PCA and PCoA showed that the POPS3 group had no significant overlap with the other groups. LEfSe analysis showed that the POPS3 group differed from the other groups in terms of the gut microbes at many different taxonomic levels. Therefore, we speculated that dietary administration of POPS could modulate the innate immune response and gut microbiota diversity of A. japonicus. Taken together, the current results provide a foundation for greater understanding of the interaction between gut microbiota and innate immunity in A. japonicus.

Elucidation of the potential mechanism of punicalagin for conferring disease resistance in Yesso scallops against Vibrio anguillarum infection

Although punicalagin (PNG) has been demonstrated to exhibit a variety of bioactivities, its disease resistance role in bivalve shellfish remains poorly understood. This study was designed to investigate the effect of PNG on immunoprotective activity in Yesso scallops (Patinopecten yessoensis) infected with Vibrio anguillarum. Surprisingly, PNG exhibited both prophylaxis and curative potential against this pathogen, as indicated by the significant increase in scallop survival rates. Additional in vitro and in vivo experiments were conducted to assess the possible mechanism by which PNG protected against pathogen infection. The results showed that PNG could cause significant damage to the membrane, suggesting that it displayed potent antimicrobial activity against V. anguillarum. At subinhibitory concentrations (SICs), PNG significantly reduced the bacterial swimming ability and inhibited the expression of some essential genes involved in virulence. Bacterial challenge experiments showed that PNG could facilitate the clearance of bacteria from the scallops. Interestingly, hemolymph immune-related enzyme activities significantly increased after PNG treatment. In addition, pre-treatment with PNG suppressed the expression of bacterially-induced immune response genes, indicating that PNG could be applied as an antibacterial drug and immunostimulant to protect pathogen-infected scallops in aquaculture.

The effect of dietary supplementation of Astragalus membranaceus and Bupleurum chinense on the growth performance, immune-related enzyme activities and genes expression in white shrimp, Litopenaeus vannamei

A 56-day feeding trial was conducted to investigate the effects of dietary supplementation of Astragalus membranaceus or/and Bupleurum chinense on the growth performance, immune enzymes, and related gene expression of Pacific white shrimp (Litopenaeus vanammei). Six experimental diets were formulated and supplemented with two levels (0.25% and 0.5%) of each herb and their combination. At the end of the trial, the specific growth rate and feed conversion ratio of shrimp were significantly (P < 0.05) improved by herbal diets. Besides, the activities of immune-related enzymes such as superoxide dismutase (SOD), alkaline phosphatase (AKP), and lysozyme in serum and hepatopancreas were significantly (P < 0.05) elevated in shrimp fed A. membranaceus or/and B. chinense. The high expression levels of immune deficiency (IMD), lysozyme, and Toll-like receptor mRNA directly or indirectly reflected the activation effect of innate immune in shrimp by dietary A. membranaceus or/and B. chinense. However, no significant difference (P > 0.05) among the herbal incorporated treatments was detected on the growth performance and immune response. In conclusion, the results suggest that A. membranaceus and B. chinense could be used as a beneficial feed additives and alternatives to antibiotics for white shrimp aquaculture.

Sesamin attenuates histological alterations, oxidative stress and expressions of immune-related genes in liver of zebrafish (Danio rerio) exposed to fluoride

Sesamin is the main lignan in sesame and is reported to have many benefits and medicinal properties. However, its protective effects against fluoride-induced damage in the liver of zebrafish have not been elucidated. Our previous studies found that fluoride exposure caused damage to the liver of zebrafish. In the study, the effects of sesamin on oxidative stress and immune damage in liver of zebrafish exposed to fluoride were measured. The results indicated that fluoride exposure damaged the microstructures of liver, increased significantly the oxidative stress, decreased remarkably the activities of ACP, AKP, and LZM, and affected obviously the expressions of immune-related genes. Treatment with sesamin remarkably attenuated fluoride-induced liver damage in a dose-dependent manner, indicated by the histopathological observation. Furthermore, sesamin treatment also significantly inhibited the production of ROS and oxidative stress, such as the decrease of lipid peroxidation level and the increase of CAT and SOD activities in liver. Sesamin treatment reversed the activities of immune-related enzymes and the expressions of immune-related genes in liver exposed to fluoride. These findings suggested that sesamin could protect the liver from fluoride-induced immune damage by oxidative stress downstream-mediated changes in reversing the activities of immune-related enzymes and the expressions of immune-related genes. Taken together, sesamin plays an important role in maintaining hepatic health and preventing liver from toxic damage caused by fluoride.

DNA damage, immunotoxicity, and neurotoxicity induced by deltamethrin on the freshwater crayfish, Procambarus clarkii.

Pyrethroid pesticides are applied to both agricultural and aquacultural industries for pest control. However, information of their impact on the commercial important freshwater crayfish, Procambarus clarkii is scarce. Therefore, the present study aimed to characterize to effects of a commonly used pyrethroid pesticide, deltamethrin on DNA damage, immune response, and neurotoxicity in P. clarkii. Animals were exposed to 7, 14, and 28 ng/L of deltamethrin, which correspond to 1/8, 1/4, and 1/2 of the LC50 (96 hours) of this pyrethroid to P. clarkii. Significant increase of olive tail moment (OTM) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) was found after deltamethrin exposure in a dose-dependent way. Total hemocyte counts (THC) and activities of immune-related enzymes including acid phosphatase (ACP), lysozyme (LZM), and phenoloxidase (PO) were all decreased and significantly lower than control at concentration of 28 ng/L after 96 hours exposure. Acetylcholinesterase (AChE) activity, an indicator of neurotoxic effect was investigated and it was decreased significantly in muscles at 14 and 28 ng/L after 24 hours exposure. The level of intracellular reactive oxygen species (ROS) in hemocytes was also measured and the significant increase of ROS was found at 14 and 28 ng/L concentrations. The results revealed that deltamethrin induced DNA damage, immunotoxicity, and neurotoxicity in P. clarkii by excessive generation of ROS. Because of the dose-dependent responses of all parameters under exposure of deltamethrin at environmentally realistic concentrations, these parameters could be used as sensitive biomarkers for risk assessment of deltamethrin in aquaculture area.

Immunomodulatory effect of ginseng stem-leaf saponins and selenium on Harderian gland in immunization of chickens to Newcastle disease vaccine

Our previous study demonstrated that ginseng stem-leaf saponins (GSLS) in combination with selenium (GSLS-Se) have adjuvant effect on the live vaccine of Newcastle disease virus (NDV) and infectious bronchitis virus (IBV) in intraocular-and-intranasal immunization in chickens. The present study was to investigate the potential molecular mechanisms involved in the immunomodulation of GSLS-Se on the Harderian gland (HG). It was found that the window allowing animals susceptible to infections due to low antibody titers became smaller or even completely closed because of increased NDV-specific HI titers when NDV vaccine and GSLS-Se were coadministered for immunization at early life in chickens. In addition, NDV-specific sIgA and the numbers of IgG+, IgA+, IgM+ plasma cells were significantly more in GSLS-Se group than the control in the HGs. Transcriptome analysis of HGs identified 1184 differentially expressed genes (DEGs) between GSLS-Se treated and non-treated groups. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses identified 42 significantly enriched GO terms and 13 canonical immune pathways. These findings indicated that GSLS-Se might exert immunomodulatory effects through influencing the antioxidant regulation and modulating the activity of immune related enzymes. Besides, Toll-like receptor (TLR) signaling pathway and mitogen-activated protein kinase (MAPK) signaling pathway might be involved primarily in the immunomodulation. Therefore, enhanced antibody responses in GSLS-Se group may be attributed to the immunomodulatory effects of GSLS-Se on the immune-related gene profile expressed in the immunocompetent cells of the HGs.

Effects of hypoxia on immune responses and carbohydrate metabolism in the Chinese mitten crab, Eriocheir sinensis

In aquaculture, hypoxia is an important stressor that can inhibit the healthy development of Chinese mitten crab, Eriocheir sinensis. The aim of this work was to research on how hypoxia (1 mg/L) followed by reoxygenation affects the immune response and carbohydrate metabolism in the Chinese mitten crab. The activities of immune-related enzymes including lysozyme (LZM), acid phosphatase (ACP), alkaline phosphatase (AKP), superoxide dismutase (SOD) and phenoloxidase (PO) and concentration changes in haemolymph glucose, trehalose and hepatic glycogen were evaluated after 8 hr of hypoxia followed by 12 hr of reoxygenation. After 8 hr of hypoxia, the activities of LZM, PO, SOD and hepatic glycogen concentration significantly decreased to the minimum when compared to the control group, but the activities of ACP and AKP, and haemolymph glucose concentration significantly increased. After 12 hr of reoxygenation, the activities of LZM, ACP, AKP and SOD recovered to the normal level except SOD in plasma, while the PO, SOD in plasma and hepatic glycogen concentration were still significantly lower than the control level. No significant change was observed in trehalose concentration during hypoxia and reoxygenation periods. These results indicated that although the activities of ACP and AKP were likely increased to facilitate the hydrolysis of foreign matter, the overall strength of the immune response was decreased as LZM, PO and SOD activities were suppressed after exposure to hypoxic conditions. The energy stores of exposed crabs were reduced due to the expenditure of energy during exposure to hypoxic stress. In general, chronic hypoxia would impair the immunocompetence and increase the energy expenditure of Chinese mitten crab, further increased the risk of pathogen infection and feed coefficient, so the negative effects of hypoxia should not be ignored.

Immune response of mollusk Onchidium struma to extremely low-frequency electromagnetic fields (ELF-EMF, 50 Hz) exposure based on immune-related enzyme activity and De novo transcriptome analysis

Along with rapid offshore and onshore wind power development in modern society, extremely low frequency electromagnetic fields (ELF-EMF) is produced extensively in the habits of aquatic organisms. However, the biological effects of ELF-EMF on aquatic organisms are almost sparse. In this study, Onchidium struma without shell was chosen to aim whether ELF-EMF can elicit immune response of mollusk based on immune-related enzyme activities and gene expression through high-throughput transcriptome sequencing. Three experimental groups, i.e. ELF-EMF unexposed control group (C), ELF-EMF (50 Hz, 100 μT) exposed E1 group, and ELF-EMF (50 Hz, 500 μT) exposed E2 group, were set, and coelomocytes were collected to analyze. The results showed that total coelomocyte and spherulocyte density in E1 group increased significantly compared to groups C and E2 (P < 0.05). There were no significant differences on amoebocyte and chromatocyte density among groups C, E1 and E2. ELF-EMF exposure could significantly increase immune-related enzyme activities in coelomic fluid of O. struma, including acidic phosphatase, alkaline phosphatase, antioxidative capacity, catalase, superoxide dismutase, and polyphenol oxidase (P < 0.05). A total of 54.32 Mb and 55.27 Mb raw reads with average length of 1520 bp were obtained from coelomocytes of O. struma in unexposed and exposed groups, respectively. There were 341 differentially expressed genes (DGEs) between unexposed and exposed groups, including 209 up-regulated and 132 down-regulated unigenes. All the DGEs were allocated to 14 Kyoto Encyclopedia of Genes and Genomes pathways, and five pathways were associated with immune response, including TLR/TNF/NOD-like receptor/MAPK/Fc epsilon RI signaling pathways. Altogether, short-term (to one week) exposure of O. struma to lower luxy density ELF-EMF (<500 μT) could elicit the immune response, and antioxidant system is recommended as indicators of immunological effects. Hopefully, this study will further provide insights into exploring biomarker for evaluation of the effect of ELF-EMF exposure on aquatic organisms regarding to field density, frequency and exposure duration, and provide good guidance for exploitation and utilization of renewable energy.

Effects of Synechococcus sp. PCC 7942 harboring vp19, vp28, and vp (19 + 28) on the survival and immune response of Litopenaeus vannamei infected WSSV

This study aimed to assess the effect of oral administration of Synechococcus sp. PCC 7942 harboring vp19, vp28, and vp(19 + 28)against infection by white spot syndrome virus (WSSV) on juveniles of Litopenaeus vannamei. L. vannamei was orally administrated by feeding with different mutants of Synechococcus for 10 days, and then challenged with WSSV. The cumulative mortality of vp19, vp28, vp (19 + 28) groups was lower than that of the positive control group (57.8%, 62.2%, 71.1%, respectively); vp (19 + 28) group had a better protection rate than vp19 and vp28 groups. The analysis of shrimp immunological parameters showed that, after WSSV injection, the activity of superoxide dismutase, phenol oxidase, catalase, and lysozyme in the hepatopancreas of vp19, vp28, and vp (19 + 28) groups was higher than in the positive group; at the same time, growth performances of L. vannamei of experimental groups were better than control groups. Results showed that the Synechococcus mutants harboring vp19, vp28, and vp (19 + 28) could be used both as drug and feed to also enhance the defensive ability of juvenile shrimp against WSSV infection by increasing the activity of immune related enzymes.