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Interleukin-6 (IL-6) is a multipotent cytokine. IL-6 plays a dual role in inflammation through both classical signaling (IL-6 binds membrane IL-6 receptor/IL-6R) and trans-signaling (IL-6 binds soluble IL-6R). However, the regulation of IL-6 activity, especially the regulation of signaling pathways and downstream genes mediated by IL-6 trans-signaling, remains largely unclear in teleost. Grass carp (Ctenopharyngodon idellus) hepatic (L8824) cells, kidney (CIK) cells, and primary hepatocytes were used as test models in this study. First, the biological activity of recombinant blunt snout bream (Megalobrama amblycephala) IL-6 (rmaIL-6) and sIL-6R (rmasIL-6R) was verified by quantitative PCR (qPCR) and western blot. The western blot results showed that rmaIL-6 significantly upregulated signal transducer and activator of transcription 3 (STAT3) phosphorylation in L8824 cells and primary hepatocytes, while rmaIL-6 in combination with rmasIL-6R (rmaIL-6+rmasIL-6R) significantly upregulated STAT3 phosphorylation in all types of cells. Furthermore, maIL-6 and maIL-6+rmasIL-6R could only induce extracellular-signal-regulated kinase 1/2 (ERK1/2) phosphorylation in L8824 cells and CIK cells, respectively. Therefore, IL-6 mainly acts by activating the janus kinase (JAK)/STAT3 pathway rather than the mitogen-activated protein kinase (MEK)/ERK pathway. Finally, the activation of the JAK2/STAT3 pathway was shown to be essential for the generation of socs3a and socs3b induced by IL-6 trans-signaling after treatment by JAK2/STAT3 pathway inhibitors (c188-9 and TG101348). These findings provide functional insights into IL-6 classical signaling and trans-signaling regulatory mechanisms in teleost, enriching our knowledge of fish immunology. [ABSTRACT FROM AUTHOR]

Photobacteriosis is a septicaemic bacterial disease affecting several marine species around the globe, resulting in significant economic losses. Although many studies have been performed related to the pathogen virulence and resistance factors, information regarding the host defence mechanisms activated once an infection takes place is still scarce. The present study was designed to understand innate immune responses of farmed juvenile gilthead seabream (Sparus aurata) after Photobacterium damselae subsp. piscicida (Phdp) infection. Therefore, two groups of seabream juveniles were intraperitoneally injected with 100 µL of PBS (placebo) or 100 µL of exponentially growing Phdp (1 × 106 CFU/mL; infected). The blood, plasma, liver, and head kidney of six fish from each treatment were sampled immediately before infection and 3, 6, 9, 24 and 48 h after infection for the broad screening of fish immune and oxidative stress responses. Infected animals presented marked anaemia, neutrophilia and monocytosis, conditions that are correlated with an increased expression of genes related to inflammation and phagocytic activity. Similar studies with different fish species and bacteria can be useful for the definition of health biomarkers that might help fish farmers to prevent the occurrence of such diseases. [ABSTRACT FROM AUTHOR]

The effects of exposure of tilapia (Oreochromis mossambicus) to sublethal concentrations of lead on hematological and immunological parameters were investigated. The fish were semistatically exposed to low (L) (0.5 mg L−1), medium (M) (2.5 mg L−1), and high (H) (5 mg L−1) lead concentrations for 14 days. At the end of the trial, red blood cell (RBC) count, hematocrit (Hct) ratio and hemoglobin levels showed significant decreases in M and H groups, while RBC was significantly increased in L group compared to control group. Lysozyme activity showed a decrease in all groups on day 14 compared to control. A decrease in myeloperoxidase activity was seen in M and H groups on day 7, and in all treatment groups on day 14. In conclusion, it was found that exposure ofO. mossambicusto lead concentrations affected hematological and immunogical parameters adversely. [ABSTRACT FROM PUBLISHER]

Development of novel systems of vaccine delivery is a growing demand of the aquaculture industry. Nano- and micro- encapsulation systems are promising tools to achieve efficient vaccines against orphan vaccine fish diseases. In this context, the use of liposomal based-nanocarriers has been poorly explored in fish; although liposomal nanocarriers have successfully been used in other species. Here, we report a new ∼125 nm-in-diameter unilamellar liposome-encapsulated immunostimulant cocktail containing crude lipopolysaccharide (LPS) from E. coli and polyinosinic:polycytidylic acid [poly (I:C)], a synthetic analog of dsRNA virus, aiming to be used as a non-specific vaccine nanocarrier in different fish species. This liposomal carrier showed high encapsulation efficiencies and low toxicity not only in vitro using three different cellular models but also in vivo using zebrafish embryos and larvae. We showed that such liposomal LPS-dsRNA cocktail is able to enter into contact with zebrafish hepatocytes (ZFL cell line) and trout macrophage plasma membranes, being preferentially internalized through caveolae-dependent endocytosis, although clathrin-mediated endocytosis in ZFL cells and macropinocytocis in macrophages also contribute to liposome uptake. Importantly, we also demonstrated that this liposomal LPS-dsRNA cocktail elicits a specific pro-inflammatory and anti-viral response in both zebrafish hepatocytes and trout macrophages. The design of a unique delivery system with the ability to stimulate two potent innate immunity pathways virtually present in all fish species represents a completely new approach in fish health. [ABSTRACT FROM AUTHOR]

Administration of glucans through immersion, dietary inclusion or injection has been found to enhance many types of immune responses, resistance to bacterial and viral infections and to environmental stress in many fish species. Although the efficacy of the glucan varies with types and administration, glucan used as an immunomodulatory and mostly immunostimulatory additive has been found satisfactory in eliciting immunity in commercial aquaculture. Development of more efficient administration methods will facilitate the routine and prophylactic use of glucans as natural immunostimulants of fish. Using a PubMed search, this review has an extensive literature on glucan in fish immunity. [ABSTRACT FROM AUTHOR]

Varying levels of lupin ( Lupinus albus), peas ( Pisum sativum) and rapeseed ( Brassica napus) meals were evaluated as partial replacements for fishmeal in extruded diets for rainbow trout, with particular emphasis on the effect on growth performance and the expression of three genes associated with immune response. A series of 10 isonitrogenous (450 g kg−1 crude protein) and isolipidic (17 g kg−1 crude lipid) diets were formulated to contain different levels of lupin (150 g kg−1, 250 g kg−1 and 350 g kg−1), rapeseed cake (100 g kg−1, 200 g kg−1 and 300 g kg−1) and pea (50 g kg−1, 150 g kg−1 and 250 g kg−1) meals. The control diet was prepared with fish meal as the sole source of protein. Triplicate groups of fish (37.08 ± 3.58 g) were assigned to each experimental diet. The feeding experiment was conducted for 9 weeks at 14.3 ± 0.4 °C. The fish were hand fed three times per day, 6 days per week to apparent satiation level. Growth performance, feed utilization and immunological response were significantly affected by the type of plant protein as well as level of inclusion. Hepatosomatic index ( HSI) increased in all groups of fish fed diets with pea and rapeseed cake meal. Dietary inclusion of lupin did not affect the expression of Mx-1 gene. Our results suggest that fish meal can be replaced by lupin in the diet of rainbow trout without any apparent adverse effects on key innate immunological genes. [ABSTRACT FROM AUTHOR]

Although previous studies have characterized some aspects of the immune response of the teleost gut in response to diverse pathogens or stimuli, most studies have focused on the posterior segments exclusively. However, there are still many details of how teleost intestinal immunity is regulated that remain unsolved, including the location of IgM+ and IgT+ B cells along the digestive tract and their role during the course of a local stimulus. Thus, in the current work, we have studied the B cell response in five different segments of the rainbow trout (Oncorhynchus mykiss) digestive tract in both naïve fish and fish orally vaccinated with an alginate-encapsulated DNA vaccine against infectious pancreatic necrosis virus (IPNV). IgM+ and IgT+ cells were identified all along the tract with the exception of the stomach in naïve fish. While IgM+ cells were mostly located in the lamina propria (LP), IgT+ cells were primarily localized as intraepithelial lymphocytes (IELs). Scattered IgM+ IELs were only detected in the pyloric caeca. In response to oral vaccination, the pyloric caeca region was the area of the digestive tract in which a major recruitment of B cells was demonstrated through both real time PCR and immunohistochemistry, observing a significant increase in the number of both IgM+ and IgT+ IELs. Our findings demonstrate that both IgM+ and IgT+ respond to oral stimulation and challenge the paradigm that teleost IELs are exclusively T cells. Unexpectedly, we have also detected B cells in the fat tissue associated to the digestive tract that respond to vaccination, suggesting that these cells surrounded by adipocytes also play a role in mucosal defense. [ABSTRACT FROM AUTHOR]

The present study aimed to investigate leucocyte responses to inflammation as well as some innate immune parameters of Senegalese sole, Solea senegalensis, following challenge with two strains of Photobacterium damselae subsp. piscicida belonging to the European and Japanese clones described for this bacterium. Pathogenicity assays were performed to assess the virulence of each Photobacterium damselae subsp. piscicida strain for sole. Subsequently, fish were intraperitoneally injected with phosphate-buffered saline (control) or two concentrations (2 × 102 and 2 × 106 CFU mL−1) of each bacterial strain and sampled after 6 and 24 h. Results showed that the European isolate induces a higher degree of response than the Japanese strain. While blood neutrophilia and monocytosis correlated well with the increase in neutrophil and macrophage numbers in the peritoneal cavity, fish infected with the European isolate presented higher peritoneal cell numbers than fish challenged with the Japanese strain. In addition, alternative complement pathway activity and respiratory burst of head kidney leucocytes increased significantly in fish infected with the European isolate. The enhanced innate immune response displayed by Senegalese sole challenged with the European isolate is probably due to the higher degree of virulence presented by this Photobacterium damselae subsp. piscicida strain. [ABSTRACT FROM AUTHOR]

Background. Traditional Chinese herbs (TCHs) are widely used for improving non-specific immunity of fish in aquaculture. Possible effects of many important TCH on red drum, Sciaenops ocellatus (Linnaeus, 1766), have not been adequately studied. The aim of the presently reported study was to investigate the effects often TCH on selected immunological- and haematological responses of red drum. Materials and methods. Ten TCH preparations, consisting of selected parts of plants and fungi, known in medicinal practice as: Astragalus membranaceus, fructus forsythiae, Polyporus umbellatus, Scutellaria baicalensis, Wolfiporia extensa, rhizoma coptidis, radix glycyrrhizae, flos lonicerae japonicae, isatidis radix, and bupleuri radix were used in the experiment. A dose of 10 g of each TCH was decocted and concentrated, then mixed with the diets (mixed diets) at ratio of 2%. After 28 days of feeding, the fish were infected with Vibrio splendidus and observed for 14 days for possible mortalities. Leukocyte phagocytic activity and lysozyme activity (LZM) were measured on days 0, 3, 7, 14, 21, 28, and 35. Relative percentage survival (RPS) of each TCH treatment was also investigated after the fish exposure to V. splendidus. Results. Red drum fed 2% doses of individual TCH extracts significantly (P < 0.05) increased its: phagocytic percentage (PP) (with the exception of flos lonicerae japonicae treatment), phagocytic index (PI) (with the exception of flos lonicerae japonicae- and bupleuri radix treatments), LZM (with the exception of Wolfiporia extensa treatment), and RPS (with the exception of P. umbellatus, Wolfiporia extensa-, radix glycyrrhizae-, flos lonicerae japonicae-, isatidis radix-, and bupleuri radix treatments). The indexes of PP, PI, and LZM, for all experimental groups, decreased quickly on day 35 (7 days after TCH diets were discontinued). On the other hand, PP values were significantly (P < 0.05) higher than in control (with the exception of flos lonicerae japonicae- and Wolfiporia extensa treatments). Also PI values were significantly higher (P < 0.05) than in control (with the exception of flos lonicerae japonicae-, Wolfiporia extensa-, and bupleuri radix treatments). LZM values exhibited no significant difference (P > 0.05) in all treatment groups compared with control. Most importantly, the A. membranaceus-, or S. baicalensis-, or fructus for-sythiae-fed groups were significantly protected (P < 0.01) against V. splendidus challenge compared to control. RPS of A. membranaceus- and S. baicalensis groups were the highest, reaching 88.9% on day 28, followed by the fructus forsythiae group, whereas bupleuri radix- and Wolfiporia extensa treatments showed the lowest values. Conclusion. A. membranaceus, S. baicalensis, and fructus forsythiae were effective in preventing red drum from acquiring the disease while challenged by V. splendidus. [ABSTRACT FROM AUTHOR]

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For most marine aquaculture species, one of the main bottlenecks is the stable production of high quality juveniles. The high and unpredictable mortality in the first weeks after hatching of marine fish larvae remains a challenging problem that needs to be solved. The severity of the problem differs between species, but cannot be considered adequately solved for any species. Both scientific evidence and experience in hatcheries for a variety of fish, shrimp and shellfish species are accumulating as support for the hypothesis that detrimental fish-microbe interactions are the cause of these problems. Host-microbe interactions in reared fish are still poorly understood, except for a few pathogens, and empirical data of the quality required to test this hypothesis, are lacking. This article provides an overview on the current knowledge of the microbial environment of fish larvae, including methodological aspects to characterize the microbial community (both using culture-dependent and culture-independent methods). Further, the current knowledge of the immunology of fish larvae is reviewed, including recent advances in the understanding of toll-like receptors, inflammatory cytokines, mast cells and piscidins, and the ontogeny of the adaptive immune system. Finally, we provide an overview of the state of the art with respect to steering of microbial communities associated with fish larvae - both steering of community composition and of its activity (e.g. by quorum sensing interference). [ABSTRACT FROM AUTHOR]

Endocrine-immune system interactions have been widely demonstrated in mammals, whereas in fish, these relationships remain unclear. Of the organs that constitute the endocrine system, the pineal gland and its secretory product melatonin act in the synchronization of daily and seasonal rhythms in most vertebrates, including fish. Seasonal differences in immunocompetence and disease prevalence have been well documented in humans. Seasonality also strongly influences the life history of fish by controlling the timing of physiological events, such as reproduction, food intake, locomotor activity, and growth performance. Apart from its synchronizing capabilities, the role of melatonin in physiological processes in fish is not thoroughly understood. The purpose of this review is to summarize current studies on the effects of melatonin on the fish immune system. These studies suggest that melatonin represents an important component of fish endocrine-immune system interactions. The elucidation of the defense mechanisms of fish will facilitate the development of health management tools to support the growing finfish aquaculture industry as well as address questions concerning the origins and evolution of the immune system in vertebrates. [ABSTRACT FROM AUTHOR]

This study investigated the effects of the co-supplementation of vitamins C (0, 500, and 1000 mg kg−1) and E (0, 62.5, and 125 mg kg−1) on the growth performance, haematology and the modulation of blood stress indicators and immune parameters in hybrid catfish ( Clarias macrocephalus × Clarias gariepinus) under combinations of thermal and acidic stress. Supplementation of vitamins C and E influenced the growth, haematological indices, serum chloride, plasma protein and immune parameters (lysozyme, total immunoglobulin and alternative complement haemolytic assay) ( P < 0.05). Although vitamins C and E did not prevent a significant reduction in serum chloride, they minimized not only the modulation of blood glucose and plasma protein, but also the reduction in immune parameters ( P < 0.05) owing to stress. Our results demonstrated that co-supplementation of 500 mg kg−1 vitamin C and 125 mg kg−1 vitamin E, or 1000 mg kg−1 vitamin C alone, for four weeks and co-supplementation of both vitamins at low levels (vitamins C at 500 mg kg−1 and E at 62.5 mg kg−1) for eight weeks had beneficial effects on the growth, amelioration of stress-mediated adverse changes in the physiological and immunosuppressive responses of hybrid catfish under stressful conditions. [ABSTRACT FROM AUTHOR]

Background: Amur ide (Leuciscus waleckii) is an economically and ecologically important species in Northern Asia. The Dali Nor population inhabiting Dali Nor Lake, a typical saline-alkaline lake in Inner Mongolia, is well-known for its adaptation to extremely high alkalinity. Genome information is needed for conservation and aquaculture purposes, as well as to gain further understanding into the genetics of stress tolerance. The objective of the study is to sequence the transcriptome and obtain a well-assembled transcriptome of Amur ide. Results: The transcriptome of Amur ide was sequenced using the Illumina platform and assembled into 53,632 cDNA contigs, with an average length of 647 bp and a N50 length of 1,094 bp. A total of 19,338 unique proteins were identified, and gene ontology and KEGG (Kyoto Encyclopedia of Genes and Genomes) analyses classified all contigs into functional categories. Open Reading Frames (ORFs) were detected from 34,888 (65.1%) of contigs with an average length of 577 bp, while 9,638 full-length cDNAs were identified. Comparative analyses revealed that 31,790 (59.3%) contigs have a significant similarity to zebrafish proteins, and 27,096 (50.5%), 27,524 (51.3%) and 27,996 (52.2%) to teraodon, medaka and three-spined stickleback proteins, respectively. A total of 10,395 microsatellites and 34,299 SNPs were identified and classified. A dN/dS analysis on unigenes was performed, which identified that 61 of the genes were under strong positive selection. Most of the genes are associated with stress adaptation and immunity, suggesting that the extreme alkaline-saline environment resulted in fast evolution of certain genes. Conclusions: The transcriptome of Amur ide had been deeply sequenced, assembled and characterized, providing a valuable resource for a better understanding of the Amur ide genome. The transcriptome data will facilitate future functional studies on the Amur ide genome, as well as provide insight into potential mechanisms for adaptation to an extreme alkaline-saline environment. [ABSTRACT FROM AUTHOR]

This interdisciplinary study investigated computational analytic methods used for biological hypothesis testing and applied the methods for the validation of the effects of nutraceuticals on growth and immune response of Nile tilapia in cool water. Farmers in cooler regions face problems with cultivating tilapia, one of the most popular cultivated fish species, due to poor survival rates at suboptimal temperatures. We hypothesized that two nutraceuticals, phosphatidylcholine and β-carotene, help tilapia adapt to cooler water temperatures and benefit tilapia's growth and immune response. Fish were reared in two different environments: warm water (28°C) and cool water (16°C). Fish reared in warm water (control) were provided with a basal commercial diet, while fish reared in cool water were provided with either the basal commercial diet (cool water control) or diets supplemented with nutraceuticals (either phosphatidylcholine or β-carotene). Experiments were conducted over an eight-week period. The effects of the nutraceuticals were tested using an unsupervised learning technique in data mining and statistics called cluster analysis. An external index used for cluster validation was adopted for testing our hypothesis by formulating the level of agreement between two different partitions of samples: experimental groups and clusters based on the similarity of their features. Contrary to the findings of previous studies, which showed the beneficial effects of phosphatidylcholine and β-carotene supplementation in a range of fish including tilapias, our test results show no significant difference among the fish reared in cool water and fed with either the basal diet or diets supplemented with the nutraceutical. Despite slower growth compared with fish held in warm waters, our study suggests the feasibility of stocking or rearing tilapia in water temperatures as low as 16°C during cool weather, without need for supplementation to basal commercial feed. [ABSTRACT FROM AUTHOR]

Two subtractive complementary DNA libraries were constructed from Nile tilapia Oreochromis niloticus vaccinated with formalin-killed Streptococcus iniae cells, and a further two constructed from O. niloticus infected with S. iniae. Of the 68 distinct expressed sequence tag (EST) contigs and singletons, 45 and 13 EST shared high similarities with genes of known and unknown functions, respectively. Ten EST contigs and singletons had no significant similarity to any sequences. Five putative immune-relevant genes, β2m, α-ha, mmp9, pgrn and cxcr4, were selected for quantitative reverse-transcription polymerase chain reaction in four strains of Oreochromis spp.: genetically improved farmed tilapia ( O. niloticus), Oreochromis aureus, O. niloticus and O. niloticus× O. aureus, with different disease resistance following infection with S. iniae. pgrn was up-regulated more significantly in disease-resistant strains than in the susceptible. α-ha was markedly down-regulated, and no significant differences in the expression level of β2m were detected. A negative correlation was observed between the expression of mmp9 and that of cxcr4. The results provide insight into the molecular response of O. niloticus to S. iniae infection. [ABSTRACT FROM AUTHOR]

We examined orexin-like immunoreactivity in the pituitary of the red-bellied piranha ( Pygocentrus nattereri). Orexin-B-immunoreactive (IR) cells corresponded to luteinizing hormone (LH)-containing cells in the pars distalis, and orexin-B-IR fibers corresponded to melanin-concentrating hormone (MCH)-containing fibers in the pars nervosa. In the pars distalis, orexin-B-IR puncta that were also immunoreactive for MCH were observed around the orexin-B-IR cells. In the ventral hypothalamus, orexin-B-IR and MCH-IR neurons were found in the nucleus lateralis tuberis. Immunoelectron-microscopic analysis revealed that the orexin-B-like substance co-localized with LH in secretory granules and with MCH in MCH-containing neurons. Some of the MCH secreted in the pituitary might participate in the modulation of LH secretion from the gonadotrophs, together with orexin-B, leading to food intake by the stimulation of growth hormone secretion from the somatotrophs. [ABSTRACT FROM AUTHOR]

Hematological and Immunological parameters of aquatic animals may be changes due to acute, subacute and chronic exposure to marine pollutants. The purpose of this study was to determine the experimental effects of water-soluble fraction (WSD) doses (0, 10, 100, 500 and 1,000 ppm) for 0, 48 h and 7 days on hematological and immunological features of juvenile great sturgeon Huso huso. Fish exposed after 48 h and 7 days showed a significant change in the white blood cell ( P < 0.01) in contrast to red blood cell ( P > 0.05). Only MCV, neutrophil and lymphocyte show significant change within 48-h exposure to WSD ( P < 0.05), whereas among significant indices, MCV and lymphocyte had been decreased and neutrophil had increased. Seven-day exposures showed a significant change in MCV, neutrophil, eosinophil and lymphocyte concentration in relation to the respective control ( P < 0.05), whereas among significant indices, neutrophils were significantly greater and MCV, eosinophil and lymphocyte were significantly lower than those in control groups ( P < 0.05). [ABSTRACT FROM AUTHOR]

Abstract: The biggest discharge from the offshore oil industry is produced water (PW). As new technologies emerge to remove oil from such discharges, the question remains as to the effect that the water soluble fraction of contaminants present in PW may have on the biota surrounding the areas of discharge. We investigated the effects of 8 weeks of intermittent exposure to environmentally relevant concentrations (100 or 1000mg/L) of the aqueous fraction of PW (AFPW) on growth parameters, food consumption, respiratory burst activity of head kidney leukocytes (RB), activity of antioxidant enzymes and mRNA expression of immune- and detoxification-related genes of Atlantic cod. No significant effects of AFPW were seen on growth parameters, food consumption and/or RB. Furthermore, the activity of antioxidant enzymes and the expression of CYP1A, GST and UGT were not impacted by AFPW treatment. The mRNA expression of some immune related genes was affected in a similar manner as what has been described in Atlantic cod exposed to full PW suggesting that short chain soluble compounds present in PW might be responsible for its immunomodulatory effect. Traditionally used biomarkers of toxicant exposure such as phase I (CYP1A) and phase II (GST, UGT) genes do not seem to be reliable indicators of exposure to AFPW. This study confirms the fact that some immune related genes are affected by soluble components of PW and that further investigation on potential increased disease susceptibility is warranted. [Copyright &y& Elsevier]

BDE-47 is one of the most widely found congeners of PBDEs in marine environments. The potential immunomodulatory effects of BDE-47 on fish complement system were studied using the marine medaka Oryzias melastigma as a model fish. Three-month-old O. melastigma were subjected to short-term (5 days) and long-term (21 days) exposure to two concentrations of BDE-47 (low dose at 290 ± 172 ng/day; high dose at 580 ± 344 ng/day) via dietary uptake of BDE-47 encapsulated in Artemia nauplii. Body burdens of BDE-47 and other metabolic products were analyzed in the exposed and control fish. Only a small amount of debrominated product, BDE-28, was detected, while other metabolic products were all under detection limit. Transcriptional expression of six major complement system genes involved in complement activation: C1r/s (classical pathway), MBL-2 (lectin pathway), CFP (alternative pathway), F2 (coagulation pathway), C3 (the central component of complement system), and C9 (cell lysis) were quantified in the liver of marine medaka. Endogenous expression of all six complement system genes was found to be higher in males than in females ( p < 0.05). Upon dietary exposure of marine medaka to BDE-47, expression of all six complement genes were downregulated in males at day 5 (or longer), whereas in females, MBl-2, CFP, and F2 mRNAs expression were upregulated, but C3 and C9 remained stable with exposure time and dose. A significant negative relationship was found between BDE-47 body burden and mRNA expression of C1r/s, CFP, and C3 in male fish ( r = −0.8576 to −0.9447). The above findings on changes in complement gene expression patterns indicate the complement system may be compromised in male O. melastigma upon dietary exposure to BDE-47. Distinct gender difference in expression of six major complement system genes was evident in marine medaka under resting condition and dietary BDE-47 challenge. The immunomodulatory effects of BDE-47 on transcriptional expression of these complement components in marine medaka were likely induced by the parent compound instead of biotransformed products. Our results clearly demonstrate that future direction for fish immunotoxicology and risk assessment of immunosuppressive chemicals must include parallel evaluation for both genders. [ABSTRACT FROM AUTHOR]

Numerous environmental chemicals, both long-known toxicants such as persistent organic pollutants as well as emerging contaminants such as pharmaceuticals, are known to modulate immune parameters of wildlife species, what can have adverse consequences for the fitness of individuals including their capability to resist pathogen infections. Despite frequent field observations of impaired immunocompetence and increased disease incidence in contaminant-exposed wildlife populations, the potential relevance of immunotoxic effects for the ecological impact of chemicals is rarely considered in ecotoxicological risk assessment. A limiting factor in the assessment of immunotoxic effects might be the complexity of the immune system what makes it difficult (1) to select appropriate exposure and effect parameters out of the many immune parameters which could be measured, and (2) to evaluate the significance of the selected parameters for the overall fitness and immunocompetence of the organism. Here, we present - on the example of teleost fishes - a brief discussion of how to assess chemical impact on the immune system using parameters at different levels of complexity and integration: immune mediators, humoral immune effectors, cellular immune defenses, macroscopical and microscopical responses of lymphoid tissues and organs, and host resistance to pathogens. Importantly, adverse effects of chemicals on immunocompetence may be detectable only after immune system activation, e.g., after pathogen challenge, but not in the resting immune system of non-infected fish. Current limitations to further development and implementation of immunotoxicity assays and parameters in ecotoxicological risk assessment are not primarily due to technological constraints, but are related from insufficient knowledge of (1) possible modes of action in the immune system, (2) the importance of intra- and inter-species immune system variability for the response against chemical stressors, and (3) deficits in conceptual and mechanistic assessment of combination effects of chemicals and pathogens. [ABSTRACT FROM AUTHOR]

Behavioural fever, manifested as an increased preferred temperature, was shown in rainbow trout Oncorhynchus mykiss following an injection of bacterial lipopolysaccharide. Simulated behavioural fever, through a 2·5° C water temperature rise following bacterial lipopolysaccharide injection, enhanced the expression of the cytokine interleukin-1 β, in comparison with an untreated group held at the initial temperature. The present findings show that an important mediator in the immune response can be boosted through behavioural fever in fishes. [ABSTRACT FROM AUTHOR]

Abstract: The innate immune system of fish is the primary defense against acute diseases. The marine medaka Oryzias melastigma has been shown to be a potential marine fish model for ecotoxicology, but little is known about the innate immune system of this small fish. In this study, suppression subtractive hybridization (SSH) was used to identify differentially expressed immune genes in the liver of O. melastigma infected with Vibrio parahaemolyticus. Among the 396 genes identified, based on NCBI BLAST search of the 1279 sequenced clones in the SSH libraries, 38 (9.6%) were involved in the immune process. Besides, genes involved in biological regulations (5.6%); cellular metabolism (24.7%); general response to stimuli (4.8%); cellular component organization (2.3%); signal transduction (2.5%) and transport process (2.8%) were also obtained. Ten complement component genes involved in four activation pathways were quantified (using q-PCR) and exhibited different patterns of transcription between the control and challenged individuals. The results reported upon here support the feasibility of developing O. melastigma as a marine model fish to understand the basic biological processes related to immune function and for immunotoxicological research. Findings of this study established a genetic platform for studying immune function using O. melastigma. [Copyright &y& Elsevier]

β-1,3-Glucan with 1.0 g kg−1 was supplemented to a basal diet [control (C)] with different feeding schedules: permanently β-1,3-glucan diet (BG) and 14 days BG-14 days control diet (C + BG). Growth and immunological responses [respiratory burst (RB), superoxide dismutase (SOD), catalase (CAT), lysozyme and total protein] in haemolymph, hepatopancreas and muscle of Litopenaeus vannamei were recorded after 84-day feeding and exposure to nitrite-N (20 mg L−1) for 120 h. β-1,3-Glucan administration did not affect growth performance. However, as compared with control, elevated CAT and lysozyme activities were seen in haemolymph of both BG groups, while significantly higher activities of SOD, lysozyme and RB in hepatopancreas, and higher activities of CAT and lysozyme in muscle were only seen in C + BG group. After nitrite-N stress, significantly higher haemolymph protein, and hepatopancreas activities of lysozyme and RB were observed in both BG groups, but significantly higher activities of haemolymph SOD was only seen in C + BG group. The mortality in groups BG and C + BG was significantly lower than that in group C, but C + BG group showed a trend of higher nitrite-N resistance compared with BG group. Considering dietary cost and immunostimulatory effects, the feeding schedule with 14 days BG-14 days control diet is more recommended. [ABSTRACT FROM AUTHOR]

Stocking shrimp at high densities increases yield during culture, but growth is generally compromised and weakened immune response associated with poor water quality has also been reported. Therefore, we tested if supplying more arachidonic acid (ARA) in the diet, a precursor of eicosanoids such as prostaglandins E from the series II (PGE2) that enhance immune response can counteract the negative effect of stocking shrimp at high densities. The effect of physical crowding was separated from the effect of water quality, both a result of high density, by using tanks divided by a hard plastic net that allowed water flow between two density conditions. Crowding reduced weight gain by 8.3%, although the effect was more evident with deteriorated water quality from combined effects of high total ammonia and low dissolved oxygen levels (18.4%), but no effect on survival was found. A clear food imprinting of ARA levels in hemocytes was observed, but ARA did not clearly counteract the negative effects of high density on overall performance. However, ARA could minimize stress response of sampling and enhance some effectors of the immune system, such as clotting and respiratory burst. The increase in PGE2 metabolite in shrimp fed with the high-ARA diet was not consistent, and thus, the effects of ARA were not necessarily mediated by these eicosanoids. [ABSTRACT FROM AUTHOR]

This study was conducted to evaluate the effect of dietary lysozyme supplementation on growth performance and plasma biochemical parameters of rainbow trout ( Oncorhynchus mykiss). Graded levels of lysozyme [0 (control), 150, 300, 450 and 600 mg kg−1 diet] were fed to fish (initial average weight 7.76 g) for 10 weeks. Dietary lysozyme supplementation regardless of inclusion level generally improved the growth, feed utilization and nutrient retention, but significant differences were mainly observed between the 450 or 600 mg kg−1 lysozyme group and the control group. Lysozyme supplementation generally decreased the plasma aspartate aminotransferase and alanine aminotransferase (ALT) activities, but significant difference was only observed in the ALT activity between the 450 mg kg−1 lysozyme group and the control group. In contrast, lysozyme supplementation generally increased the plasma alkaline phosphatase and lysozyme activities, but significant difference was only observed in the lysozyme activity between the 600 mg kg−1 lysozyme group and the control group. Lysozyme supplementation generally increased the plasma antioxidant activities of enzymes (including superoxide dismutase, glutathione peroxidase and catalase) and total antioxidant capacity, but decreased the plasma malondialdehyde level. These results suggest that dietary 450-600 mg kg−1 lysozyme inclusion may improve the growth and non-specific immune response of rainbow trout. [ABSTRACT FROM AUTHOR]

The effect of dietary administration of Lactococcus lactis MM1 and Enterococcus faecium MM4, two strains of lactic acid bacteria isolated from the gut of juvenile grouper Epinephelus coioides, on the growth, feed utilization, digestive enzymes and immune response of juvenile E. coioides was evaluated. The fish were fed for 60 days with three different diets: control diet (without probiotic), diet P1 supplemented with 1.0 × 108 CFU g−1 L. lactis or diet P2 with 1.0 × 108 CFU g−1 E. faecium. Although growth and feed intake decreased slightly, significant improvement of feed utilization was observed in fish fed diet P1 and diet P2 for 60 days. The hepatopancreatic protease activities in the two probiotic treatments were significantly higher than that in the control. The phagocytic activity, serum superoxide dismutase activity and complement component 4 (C4) and IgM levels were not significantly affected by diet P1 and diet P2. Serum complement component 3 (C3) levels in the two treatments were significantly higher than that in the control. Significant increased serum lysozyme activity was observed in fish fed the diet P1, while significant decreased lysozyme activity was observed in fish fed the diet P2 compared with the fish fed the control diet. There was a significant interaction effect between diet and administration date for the complement C4. The study demonstrates potential for L. lactis MM1 and E. faecium MM4 to improve the feed utilization and modulate the immune function in E. coioides. [ABSTRACT FROM AUTHOR]

The aim of the study was to determine the impact of applying different proportions of linseed (LO) and sunflower (SFO) oils in pikeperch diets on growth, histological changes in the liver, immunological and blood chemical parameters. The fish were fed isoenergetic and isoprotein feeds containing SFO (group 100SFO) or LO (group 100LO) in quantities of 67 g kg/feed, and a mixture of oils: 47 g SFO and 20 g LO kg/feed (group 70SFO/30LO) and 20 g SFO and 47 g LO kg/feed (group 30SFO/70LO). Dietary ratios of polyunsaturated fatty acids from the n-3 and n-6 series (n3/n6 index) were 0.36-2.15. Pikeperch were reared for 56 days in three replicates for each dietary treatment. Various dietary oils and ratios of n3/n6 did not impact fish growth, feed conversion ratio, viscerosomatic and hepatosomatic index, and size of the hepatocytes. Feeding the fish high quantities of LO and SO oils (groups 100LO and 100SFO) reduced the immunological response of the phagocytes and lymphocytes in the fish. Moreover, this resulted in significant differences among groups in the quantity of linolenic and linoleic acid in whole fish bodies, viscera, fillets, and livers. Various quantities of vegetable oils in the fish diets did not impact the quantity of arachidonic, eicosapentaenoic and docosahexaenoic acid in the fillets and livers. The immunological index and low quantities of linoleic acid in the fillets obtained in group 30SFO/70LO indicate that the n3/n6 dietary ratio of 1.35 was the most advantageous for feeding juvenile pikeperch feeds with vegetable oils. [ABSTRACT FROM AUTHOR]

Two of the most commonly used elasmobranch experimental model species are the spiny dogfish Squalus acanthias and the little skate Leucoraja erinacea. Comparative biology and genomics with these species have provided useful information in physiology, pharmacology, toxicology, immunology, evolutionary developmental biology and genetics. A wealth of information has been obtained using in vitro approaches to study isolated cells and tissues from these organisms under circumstances in which the extracellular environment can be controlled. In addition to classical work with primary cell cultures, continuously proliferating cell lines have been derived recently, representing the first cell lines from cartilaginous fishes. These lines have proved to be valuable tools with which to explore functional genomic and biological questions and to test hypotheses at the molecular level. In genomic experiments, complementary (c)DNA libraries have been constructed, and c. 8000 unique transcripts identified, with over 3000 representing previously unknown gene sequences. A sub-set of messenger (m)RNAs has been detected for which the 3′ untranslated regions show elements that are remarkably well conserved evolutionarily, representing novel, potentially regulatory gene sequences. The cell culture systems provide physiologically valid tools to study functional roles of these sequences and other aspects of elasmobranch molecular cell biology and physiology. Information derived from the use of in vitro cell cultures is valuable in revealing gene diversity and information for genomic sequence assembly, as well as for identification of new genes and molecular markers, construction of gene-array probes and acquisition of full-length cDNA sequences. [ABSTRACT FROM AUTHOR]

Summary Juvenile channel catfish, Ictalurus punctatus, were fed diets supplemented with yeast or yeast subcomponents (YYS) as commercial preparations of β-glucan (MacroGard® and Betagard A®), mannan oligosaccharide (Bio-Mos® Aqua Grade), or whole-cell Saccharomyces cerevisiae (Levucell SB20®) at the manufacturers' recommended levels. Fish were fed experimental diets for 1 or 2 weeks prior to disease challenge (pre-challenge feeding periods) and sampled at the end of each feeding period to measure haematological and immune parameters and to determine the effects of dietary YYS on resistance to Edwardsiella ictaluri, the causative agent of enteric septicaemia disease (ESC). Feeding of experimental diets continued for 3 weeks post-challenge. In channel catfish fed diets supplemented with MacroGard®, Betagard A®, or Levucell SB20®, survival in the 1 week pre-challenge feeding group and antibody titres in the 2 week feeding group were significantly higher post- E. ictaluri challenge in relation to catfish fed with the control diet. In fish fed these same three diets, survival to ESC was significantly higher after 1 week vs. 2 weeks feeding, while the antibody response was significantly higher after 2 weeks vs. 1 week. Lysozyme activity was also higher in the 1 week feeding group, but the increased activity was unrelated to diet. Feeding YYS-supplemented diets for a shorter duration of 1 week prior to challenge may prove beneficial in increasing resistance to ESC in channel catfish. However, we cannot discount that feeding YYS diets during the recovery period may have contributed to 'glucan overload' and reduced survival in the 2 week feeding group. [ABSTRACT FROM AUTHOR]

The present study was performed to investigate the effects of a commercially available probiotic product (compound probiotic) containing Bacillus subtilis 7.0 × 109 CFU g−1, Bacillus licheniformis 3.0 × 109 CFU g−1, Lactobacillus spp. 5.0 × 108 CFU g−1 and Arthrobacter spp. 1.0 × 108 CFU g−1 on the growth performance, non-specific immunity and protection against Vibrio harveyi infection in cobia ( Rachycentron canadum). Fish were fed diets containing six graded levels of compound probiotic (0.0, 1.0, 2.0, 3.0, 4.0 and 5.0 g kg−1) for 8 weeks. The results showed that the survival rate ranged from 81.1% to 84.4% with no significant difference among dietary treatments ( P > 0.05) after feeding experiment. Dietary compound probiotic significantly increased the specific growth rate (SGR), serum lysozyme, alternative complement pathway (ACP) activity, phagocytosis percentage (PP) and respiratory burst activity of head-kidney macrophages of cobia. Moreover, feeding of supplemented diets containing compound probiotic resulted in significantly lower mortality against the pathogens Vibrio harveyi compared with the control group. To elevate the growth and immune resistance ability of cobia, an optimal dose of dietary compound probiotic administration determined by second-order polynomial regression analysis was 3.3 g kg−1, on the basis of the SGR and mortality after challenge with V. harveyi. [ABSTRACT FROM AUTHOR]

An 8-week feeding test was conducted to quantify the dietary arginine requirement of juvenile largemouth bass (LMB) (25 ± 0.4 g). Six isonitrogenous and isolipidic (459 g crude protein and 122 g crude lipid kg−1 dry diet) diets were formulated to contain graded levels of arginine (17.0-30.1 g kg−1 dry diet). Zein-coated crystalline amino acid mixtures were supplemented to simulate, except for arginine, the amino acid profile of the muscle protein of LMB. Each diet was randomly assigned to quadruplicate tanks of 35 fish reared in a flow-through system. Fish were fed to apparent satiation twice daily. Weight gain (WG) was significantly affected by dietary arginine level. Nitrogen retention was significantly lower in fish fed D17.0. Arginine retention significantly decreased with dietary arginine increased. Threonine, leucine and lysine concentrations in whole body were significantly affected by dietary arginine level. Serum lysozyme activity, serum protein and respiratory burst of head kidney leucocytes were significantly affected, while complement activity (CH50) showed no difference among treatments. Based on broken-line analysis for WG against dietary digestible arginine level, the arginine requirement of LMB was 19.1 g kg−1 of dry diet (41.6 g kg−1 of crude protein). [ABSTRACT FROM AUTHOR]

The dietary supplementation of prebiotics, probiotics and symbiotic in hybrid surubins (a Pseudoplatystoma corruscans and P. fasciatum cross) was evaluated for the effects on their autochthonous intestinal microbiota and on haematological and immunological parameters. A total of 160 fish were divided into four treatment groups with four replicates each. The treatment groups were fed with the following diets for 15 days: control diet without supplementation; 0.5% inulin (prebiotic) supplementation; Weissella cibaria (CPQBA 001-10 DRM 02) (7.87 ± 0.2 log CFU g−1) supplementation; or 0.5% inulin and W. cibaria supplementation (symbiotic group). The midgut intestines of the fish with the symbiotic diet supplementation had higher concentrations of lactic acid bacteria (7.07 ± 1.11 log CFU g−1) and low levels of Vibrio spp (1.90 ± 0.60 log CFU g−1) and Pseudomonas spp (2.23 ± 1.48 log CFU g−1). In addition, increased erythrocytes and reduced circulating neutrophils were observed in this group. No differences in blood glucose, serum protein or lysozyme levels were detected between treatment groups. However, a higher concentration of total immunoglobulin was observed in fish fed with the probiotic and symbiotic diets. The addition of 0.5% inulin (prebiotic) thus W. cibaria (probiotic) to the diet of Pseudoplatystoma hybrid surubins reduce the number of pathogenic bacteria and stimulate the beneficial intestinal microbiota and may possibly alter their immune defence system. [ABSTRACT FROM AUTHOR]

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In the present study, the immunotoxicity of 1-methyl-3-octylimidazolium bromide ([C8mim]Br) on brocarded carp was evaluated by an acute exposure of 100–300mgL−1 of [C8mim]Br for 7 days. The results showed 300mgL−1 of [C8mim]Br exposure caused activity inhibition of specific and non-specific immune systems, mainly including IgM level, lysozyme activity, and complement C3 content, while 100mgL−1 of [C8mim]Br activated fish immune system during the early periods of exposure (2–5 days). This result indicates that [C8mim]Br has immunotoxicity on brocarded carp. Additionally, histological observation revealed that 300mgL−1 of [C8mim]Br-exposure led to remarkable damages to the hepatopancreas, kidney, and spleen of brocarded carp after 7 days of [C8mim]Br treatment, although not only change in kidney and spleen somatic indexes was found, but also no swelling or hemorrhage of carp viscera occurred. [Copyright &y& Elsevier]

Fish genomes possess three type II interferon (IFN) genes, ifnγ1, ifnγ2 and ifnγ-related (ifnγrel). The IFNγ-dependent STAT signalling pathway found in humans and mice had not been characterized in fish previously. To identify the antiviral functions and signalling pathways of the type II IFN system in fish, we purified the ifnγ1, ifnγ2 and ifnγrel proteins of ginbuna crucian carp expressed in bacteria and found them to elicit high antiviral activities against crucian carp hematopoietic necrosis virus. We also cloned two distinct ifnγ receptor alpha chain (ifngr1) isoforms, 1 and 2, and stably expressed them in HeLa cells by transfecting the cells with ifngr1-1 or ifngr1-2 cDNA. When receptor transfectants were treated with the ligands in a one-ligand-one-receptor manner (ifnγ1 and ifngr1-2 or ifnγ2 and ifngr1-1), the stat1 protein was phosphorylated at both serine-727 and tyrosine-701 residues. Gel shift mobility analysis and reporter assay clearly showed that the specific ligand–receptor interaction resulted in the binding of the stat1 protein to the GAS element and enhanced transcription. Therefore, the actions of ifnγ1 and ifnγ2 were found to be mediated by a specific receptor for each signalling pathway via a stat1-dependent mechanism. [ABSTRACT FROM PUBLISHER]

Abstract: Aim: An antimicrobial validatory screening of puffer fish is done in such a way Arothron immaculatus a puffer fish skin and liver extracts were subjected for antimicrobial assay. Methods: Antimicrobial screening assay was done in ten consecutive human pathogenic bacterial and fungal pathogens using the standard disc diffusion method. Results: The results confirmed a positive test against most of the pathogens used. Maximum antimicrobial effect against Staphyloccocus aureus of 2.5 mm in liver extract and 9.8 mm of antibacterial effect against Vibrio cholera in skin extract is reported. There is no antifungal effect. Conclusion: This experiment confirms that puffer fish is a source of antimicrobial potence. [Copyright &y& Elsevier]

The present study investigated the immunomodulatory activities of alginic acid and fucoidan, both derived from brown seaweeds, on selected cellular immune responses and antibacterial activity of head kidney (HK) leukocytes of cod, Gadus morhua. Primary cultures of HK leukocytes were incubated with either 10 or 100 μg ml of the substances and the effects on respiratory burst, cellular proliferation, acid and alkaline phosphatase activity and cellular myeloperoxidase were measured at 3- and 24-h post-incubation. The antibacterial activity of the supernatants collected from the cell cultures incubated with 100 μg ml of the substances were tested against Vibrio anguillarum and Aeromonas salmonicida. Respiratory burst was significantly elevated in cells incubated with either alginic acid or fucoidan in a dose-dependent manner. Incubation with a higher dose of alginic acid and fucoidan resulted in lower cellular proliferation at 3- and 24-h, respectively. Both acid and alkaline phosphatase activities of HK leukocytes were not significantly modulated, except for a slight elevation of acid phosphatase in cells incubated with 100 μg ml of alginic acid for 24-h. Fucoidan, but not alginic acid significantly increased cellular myeloperoxidase activity at a concentration of 100 μg ml. The growth of the bacteria in both the treated and control supernatants was significantly lower than what was observed in the bacterial culture medium. However, the supernatants from the treated cells had significantly higher bacterial growth compared with supernatants of the control cells. Taken together, these results showed that at the tested concentrations, both alginic acid and fucoidan are able to differentially stimulate some cellular immune responses of cod HK leukocytes in vitro and the respiratory burst activity was significantly stimulated by these brown algal derivatives. These substances could be tested as potential immunostimulants in future in vivo studies. [ABSTRACT FROM AUTHOR]

CD4CD25Foxp3 regulatory T cells (Treg cells) are critical for the maintenance of peripheral tolerance, and the suppression of autoimmune diseases and even tumors. Although Treg cells are well characterized in humans, little is known regarding their existence or occurrence in ancient vertebrates. In the present study, we report on the molecular and functional characterization of a Treg-like subset with the phenotype CD4-2CD25-likeFoxp3-like from a pufferfish ( Tetraodon nigroviridis) model. Functional studies showed that depletion of this subset produced an enhanced mixed lymphocyte reaction (MLR) and nonspecific cytotoxic cell (NCC) activity in vitro, as well as inflammation of the intestine in vivo. The data presented here will not only enrich the knowledge of fish immunology but will also be beneficial for a better cross-species understanding of the evolutionary history of the Treg family and Treg-mediated regulatory networks in cellular immunity. [ABSTRACT FROM AUTHOR]

Ranched southern bluefin tuna Thunnus maccoyii were fed baitfishes supplemented with vitamins (predominantly E and C) or vitamins and immunostimulants, nucleotides and β-glucans, over 12 weeks after transfer and monitored for enhancement in immune response, health and performance through their 19 week grow-out period. Fish from two different tows were sampled separately at three different sampling points: at transfer to grow-out pontoons, at 8 weeks post-transfer and at harvest, 19 weeks post-transfer. Lysozyme activity was enhanced during vitamin supplementation compared to control fish. Performance ( i.e. survival, condition index and crude fat), health ( i.e. blood plasma variables including pH, osmolality, cortisol, lactate and glucose) and alternative complement activity were not commonly improved through diet supplementation. There were some tow-specific improvements in performance through vitamin supplementation including survival, selected parasite prevalence and intensity, and alternative complement activity. Immunostimulant supplementation also showed a tow-specific improvement in plasma cortisol level. Tow-specific responses may suggest that life history, previous health condition and husbandry can affect the success of vitamin and immunostimulant enhancement of immune response, health and performance of ranched T. maccoyii. [ABSTRACT FROM AUTHOR]

In diverse animal species, from insects to mammals, females display a more efficient immune defence than males. Bateman's principle posits that males maximize their fitness by increasing mating frequency whereas females gain fitness benefits by maximizing their lifespan. As a longer lifespan requires a more efficient immune system, these implications of Bateman's principle may explain widespread immune dimorphism among animals. Because in most extant animals, the provisioning of eggs and a higher parental investment are attributes of the female sex, sex-role reversed species provide a unique opportunity to assess whether or not immune dimorphism depends on life history and not on sex per se. In the broad-nosed pipefish Syngnathus typhle, males brood and nourish the eggs in a ventral pouch and thus invest more into reproduction than females. We found males to have a more active immune response both in field data from four populations and also in an experiment under controlled laboratory conditions. This applied to different measures of immunocompetence using innate as well as adaptive immune system traits. We further determined the specificity of immune response initiation after a fully factorial primary and secondary exposure to a common marine pathogen Vibrio spp. Males not only had a more active but also a more specific immune defence than females. Our results thus indeed suggest that the sex that invests more into the offspring has the stronger immune defence. [ABSTRACT FROM AUTHOR]

A 60-day feeding trial was conducted to assess the effect of incorporating dietary Psychrobacter sp., one predominant bacterium with antagonistic activity in the gut of fast-growing grouper Epinephelus coioides, on the growth, feed utilization, digestive enzymes and immune responses of E. coioides at regular monthly intervals. The fish were fed with control diet (without probiont) or probiotic diet supplemented with 1.0 × 10 CFU g Psychrobacter sp. No significant improvement in weight gain (WG) and specific growth ratio (SGR) were observed in the probiotic group, but a significant improvement in feed conversion ratio (FCR) was observed in fish fed the probiotic diet for 60 days. Although not statistically significant, enhanced hepatopancreatic protease and lipase activities and intestinal amylase activity were observed in probiotic group at day 60. A slightly increase in phagocytic activity and phagocytic index was observed in fish fed probiotic diet for 60 days. Serum lysozyme activity showed no significant differences between the probiotic group and the control group during the whole experiment period, while an increasing trend of superoxide dismutase (SOD) activity in the probiotic group was observed. Serum complement component 3 (C3) level of the probiotic group was higher than that of control in the whole feeding period, while complement component 4 (C4) level of the probiotic group was significantly higher than that of the control at day 60. The results of the current study firstly demonstrated potential for Psychrobacter sp. as a novel probiont to improve feed utilization, digestive enzymes and innate immunity in E. coioides. [ABSTRACT FROM AUTHOR]

Two primary ways to achieve low-cost, nutritionally efficacious diets for sunshine bass ( Morone chrysops × M. saxatilis) are to decrease crude protein (CP) levels and the use alternative animal or plant ingredients to partially, or totally, replace fish meal. A 459-day feeding trial was conducted with juvenile (35 g) sunshine bass to evaluate growth, feed efficiency, size distribution at harvest, immune function status and body composition when fed diets containing soybean meal (SBM), feed-grade poultry by-product meal (PBM), and supplemental methionine as complete replacements for menhaden fish meal (MFM) at 300 g kg diet, while simultaneously reducing dietary crude protein (CP; 320, 360, and 400 g kg). The feeding trial was conducted in 12, 0.04-ha earthen ponds stocked at a rate of 300 per pond (3000/ac). At 400 g kg dietary protein, there were no differences in responses between fish fed the diet containing MFM or the diet in which MFM was completely replaced with PBM and supplemental methionine on a digestible protein basis. However, final mean weight, percentage weight gain, specific growth rate, and protein efficiency ratio were linearly related ( P < 0.10) to dietary protein level in the diets while no significant differences were found in feed intake and feed conversion ratio. The expected odds of fish at harvest being classified into larger size categories (> 680 g) decreased as dietary protein level decreased based on ordinal logistic regression. There were no significant relationships between body compositional indices and dietary treatments. Body fat ranged from 56 g kg to 62 g kg, single fillets ranged from 28% to 30%, and livers ranged from 2.45% to 2.62% of body weight across treatments. Fillet protein concentration was positively linear and quadratic for protein level in the diet but fillet moisture, lipid and ash did not differ among diets. Total serum protein, immunoglobulin and lysozyme activity decreased linearly with decreasing diet protein level. These results suggest that complete replacement of MFM with feed grade PBM and supplemental methionine is possible in diets for sunshine bass and that further reductions in dietary protein level may be possible with amino acid supplementation. [ABSTRACT FROM AUTHOR]

Using suppression subtractive hybridization technique, a purpose-designed cDNA library was established to investigate the changes in gene expression and isolate the immune-related genes induced or activated by live attenuated Vibrio anguillarum. Forty-eight genes were obtained in flounder immune tissues, including cytokines, cytokine receptors, cell surface molecules, transcription factors, complement components, antimicrobial peptides and cell surface molecules. Among them, seven genes were found for the first time in flounder, named mannose-binding lectin-associated serine protease (MASP) gene, mannose-binding lectin, QM gene, tumour necrosis factor superfamily member 13b (BAFF), natural killer-lysin, chemotaxin and nuclear factor κB (NF-κB). The expression of four selected genes encoding MASP, QM, BAFF and NF-κB was further studied in immune tissues of the flounder. An obviously up-regulated expression was observed in live and spleen between challenged and control fish. These results could be beneficial for a better understanding of the immune mechanism in flounder. [ABSTRACT FROM AUTHOR]

The effect of promoted biota on the production parameters, water quality, nutritional and immunological condition of Litopenaeus vannamei was assessed in semi-intensive ponds. Earthen ponds were used as experimental units: three with formulated + natural promoted feed + shrimp (T1), three with formulated feed + shrimp (T2), and three with promoted natural feed without shrimp (Control). The dissolved oxygen (DO) levels were optimal for all treatments (≥6 mg L) as well as the pH (8.4-8.6). Total ammonia nitrogen was greater in T2 (0.10 mg L) than T1 (0.07 mg L) and the Control (0.06 mg L). Phytoplankton, zooplankton and benthos were more abundant in T1 and the Control. The promotion of natural feed had a positive effect on all the production parameters of shrimp with an increase of 19.0%, 3.5% and 23.9% in weight gain, survival, and final biomass, respectively; also it was observed a decrease of 13.9% in feed conversion ratio. No differences in haemolymph parameters were observed for nutritional indicators (glucose, cholesterol, proteins, and triglycerides) nor for immunological response (phenoloxidase and prophenoloxidase). The results indicate that the promotion of biotic communities enhances the production parameters of farmed shrimp, without affecting the nutritional and immunological status. Also the water quality was improved by the presence of biota. [ABSTRACT FROM AUTHOR]

The aim of this experiment was to determine the effects of dietary supplementation of Bio-Mos as a source of mannan oligosaccharide (MOS) on the growth, survival, immunity and digestive enzyme activity of freshwater crayfish, Cherax destructor (yabby). A basal diet and another diet with 0.4% of Bio-Mos supplemented to the basal diet were formulated. Each diet was provided to eight yabbies (35.14 ± 0.48 g, initial weight) replicated 3 times in individual 250-L plastic cylindrical tanks for a duration of 56 days. Each tank was provided with an independent recirculating water system filtered with a biological filtration. Growth parameters such as weight, specific growth rate and average weekly gain of Bio-Mos-fed yabbies were higher ( P < 0.05) than yabbies fed the control diet. Total haemocyte count, granular cells and semi-granular cells were also higher in the yabbies fed Bio-Mos diet. Protease activity was higher in hepatopancreas, and amylase activity was higher in the guts of yabbies fed Bio-Mos diet. The results implies that supplementation of MOS through Bio-Mos can effectively improve growth and immunological condition of yabbies. [ABSTRACT FROM AUTHOR]

The antioxidant defence and immune response of rainbow trout ( Oncorhynchus mykiss) that had received plant oils, rich in either n-3 polyunsaturated fatty acids (PUFA; linseed oil) or n-6 PUFA (safflower oil) was evaluated upon antigen exposure. The fish employed in this study had been offered the diets for 18 months from the first feeding. Rainbow trout from each group were injected intraperitoneally with formalin-killed bacteria ( Aeromonas hydrophila) or were sham-injected and observations were made 24 h later. Though the fish fed safflower oil seemed to be under relatively greater oxidative stress, the antioxidant defences (superoxide dismutase, catalase, glutathione peroxidase) were as effective as in those fed linseed oil. The humoral (alternate complement activity and lysozyme activity) and cellular (phagocytic activity and lymphocyte proliferation) immune responses were not significantly affected by the oil offered. With the exception of reactive oxygen production that was significantly greater in the linseed oil fed fish, both groups did not differ greatly in their immune responses after antigen exposure. Thus, fish fed safflower oil that was deficient in n-3 PUFA was able to sustain most of the critical responses similar to those fed linseed oil suggesting that plant oils of both fatty acid categories were effective for this fresh water fish. [ABSTRACT FROM AUTHOR]

Viral diseases are a major problem in Atlantic salmon aquaculture. The development of more effective viral vaccines is crucial for a sustained control of viral diseases in salmon farming because the present viral vaccines are much less effective than the bacterial vaccines. On the other hand, research and lessons from Norwegian aquaculture suggest that major progress in the control of viral diseases can still be made through classical combat principles. Improved and enforced strategies for avoidance and control of viral pathogens by breaking horizontal transmission have yielded encouraging results both for the infectious salmon anaemia virus (ISAV) and for the pancreas disease virus (PDV). More emphasis should also be placed on the possible vertical transmission of viral pathogens. Interestingly, salmon appears to have a relatively strong innate immunity against viruses as it possesses a very well-developed interferon system. Interferons protect salmon cells very well against the infectious pancreatic necrosis (IPN) and PDV and salmon show high resistance against these viruses in challenge experiments. In contrast, these viruses cause high mortality in salmon farming. This suggests that the avoidance of production conditions that result in the suppression of the immune system is of primary importance for the prevention of IPN and PD in the aquaculture industry. Interferons protect salmon cells against the ISAV less effectively, which confirms that ISA must be combated by avoidance and vaccination. Breeding of virus-resistant salmon shows promising results, especially with respect to IPN. Finally, to effectuate the above combat principles, it is important to educate highly competent aquamedicine personnel within the aquaculture industry. In Norway, this is accomplished through a 5-year integrated MSc programme in Aquamedicine. [ABSTRACT FROM AUTHOR]

Background. Fish gut bacteria may be used as probiotics for fish. Those occurring in the gastrointestinal (GI) tract of rohu, Labeo rohita (Hamilton, 1822), have not been sufficiently studied. This study was intended: to detect bacteria in the intestine of rohu by scanning electron microscopy (SEM); to evaluate the existence of heterotrophic, proteolytic, amylolytic, and cellulolytic bacteria in three different regions of the gut of rohu; and to identify more than 25% of the isolated gut bacteria by 16S rRNA. Materials and Methods. The GI tracts were removed and divided into three regions: foregut, midgut, and hindgut. Tissues used for SEM were fixed in glutaraldehyde, washed in heparinised saline, dehydrated in graded ethanol, fixed in amyl acetate, dried with liquid nitrogen, coated with gold, observed, and photographed. Homogenates of the intestinal segments were spread onto tryptic soy agar plates and selected nutrient media plates to determine heterotrophic, proteolytic, amylolytic, and cellulolytic bacterial populations, respectively. Of the 59 adherent bacterial strains isolated from the GI tract of rohu 16 isolates were tried for identification by 16S rRNA genes. Results. Bacteria were observed to adhere to the gut enterocyte surfaces. Population level of enzyme-producing bacteria was higher in the midgut and hindgut regions than that observed in the foregut region. Furthermore, dense amylolytic and cellulolytic bacterial population in comparison to the proteolytic population was noticed in the GI tract of L. rohita. Highest density of the cellulolytic bacterial population in the hindgut region may indicate that fermentative degradation occurs in this part of the GI tract. Eleven adherent bacterial strains belonged to bacilli, 2 strains to Pseudomonas, 1 strain to Aeromonas, 1 strain was most closely related to Enterobacter, while 1 strain showed < 97% 16S rRNA sequence similarity in BLAST program was treated as unknown. Conclusion. Autochthonous bacteria were present in the GI tract of rohu and that the autochthonous microbiota possess enzymatic activity that might be beneficial for the fish. [ABSTRACT FROM AUTHOR]

Background. Various compounds are being used as immuno-stimulants in various aquaculture feed types but the importance of their prolonged use is at present unknown. It is also true for those intended to modify trout susceptibility to white spot disease caused by Ichthyophthirius multifiliis. The immuno-modulating effects on rainbow trout of short- and long-term feeding using dry feed with inclusion of beta-glucan (0.2%) have therefore been evaluated. Materials and Methods. The immune reactivity was assessed by measuring susceptibility to I. multifiliis infections and plasma lysozyme in the host, factors which are considered innate response parameters. Rainbow trout, Oncorhynchus mykiss (Walbaum, 1792) (Actinopterygii: Salmoniformes: Salmonidae), were fed (control feed or glucan-containing feed) for 14 or 35 days before challenge (exposure to infective I. multifiliis theronts) and the resulting infection (number of trophonts in the skin) was recorded on day 11 post-exposure to theronts. Results. All fish obtained infection following parasite exposure but glucan-fed fish showed a lower infection at day 46 compared to fish fed control-feed. The lysozyme activity of fish plasma was evaluated throughout the experimental period and found slightly but significantly increased in association with glucan-feeding at day 14, 17, and 46. Conclusion. No evidence for an exhaustion of these selected innate response parameters due to prolonged glucan- feeding could be detected within the experimental period of 46 days. [ABSTRACT FROM AUTHOR]