Non-specific Immune Parameters Research Articles

Fishmeal substitution for Arthrospira platensis in juvenile mullet (Mugil liza) and its effects on growth and non-specific immune parameters

Background: Cyanobacterium Athrospira platensis (Spirulina) is a potential fishmeal (FM) substitute in fish diets because of its high protein content, antioxidant and immunostimulant properties. Objective: To evaluate the effects of total and partial substitution of FM with A. platensis (0, 30, 50, 70 and 100% substitution) in juvenile mullet (Mugil liza). Methods: Juvenile mullets (n=210) were maintained in a recirculation system under optimal water parameters for the species. Mullets were fed five experimental diets for 80 days. Each diet was tested in triplicate tanks. At the end of the experimental period growth parameters were measured and samples of blood, liver and spleen were taken to evaluate the immune system. Results: Full replacement (100%) of FM resulted in growth deficits and low survival. The FM replacement induced changes in the proportion of macrophages and lymphocytes. Up to 50% FM replacement increased the expression of CD3 receptors in spleen T lymphocytes (T-Cells), whereas >50% FM replacement decreased the expression of CD3 receptors. We also found that partial FM substitution diminished the apoptotic process. Conclusions: Up to 50% FM substitution with A. platensis can improve performance of non-specific immune system of mullets.Keywords: apoptosis, CD3, fish, immunostimulant, microalgae, Spirulina. ResumenAntecedentes: La cianobacteria Arthrospira platensis (Spirulina) puede usarse como substituto potencial de la harina de pescado (HP) por su alto contenido de proteína, sus antioxidantes y sus propiedades inmunoestimulantes. Objetivo: Analizar el efecto de la substitución parcial y total de HP por A. platensis (0, 30, 50, 70 y 100% de substitución) en juveniles de lisa (Mugil liza). Métodos: Juveniles de lisa (n=210) se mantuvieron en un sistema de recirculación con parámetros de calidad de agua en niveles óptimos para la especie. Las lisas se alimentaron con las dietas experimentales durante 80 días. Cada dieta fue evaluada en triplicado. Al final del periodo experimental se midieron los parámetros de crecimiento y se colectaron muestras de sangre, hígado y bazo para evaluación del sistema inmune. Resultados: La substitución total (100%) resultó en deficiente crecimiento y baja sobrevivencia. El remplazo de HP produjo cambios en las proporciones de macrófagos y linfocitos. La substitución de hasta un 50% HP aumentó la expresión de receptores CD3 en linfocitos T del bazo. Por otro lado, la substitución mayor a 50% HP disminuyó la expresión de receptores CD3. La substitución parcial de HP disminuyó el proceso de apoptosis. Conclusiones: Proponemos una substitución de HP del 50% por A. platensis, lo cual mejora el desempeño del sistema inmune no especifico de las lisas.Palabras clave: apoptosis, CD3, inmunoestimulante, microalga, pez, Spirulina. ResumoAntecedentes: A cianobactéria Athrospira platensis (Spirulina) é um potencial substituto da farinha de peixe (FP) pelo seu alto conteúdo de proteína, antioxidantes e características imune estimulantes. Objetivo: Foram avaliados os efeitos da substituição parcial e total da FP por A. platensis (0, 30, 50, 70 e 100% substituição) em juvenis de tainha (Mugil liza). Métodos: Juvenis de tainha (n=210) foram mantidos em um sistema de recirculação com os parâmetros da água sendo mantidos em níveis ótimos para a espécie. As tainhas foram alimentadas com as dietas experimentais por 80 dias, cada dieta foi testada em triplicata, ao final do período experimental foram avaliados os parâmetros de crescimento e amostras de sangue, fígado e baço foram coletadas para a avaliação do sistema imune. Resultados: A substituição total de FP resultou em redução do crescimento e baixa sobrevivência. A avaliação do sistema imune demostrou que a substituição da FP produz alterações nas proporções de macrófagos e linfócitos. Provou-se que até 50% de substituição da FP incrementa a expressão de receptores CD3. Além disso, a substituição parcial da FP diminui o processo de apoptose. Conclusão: Baseado em nossos descobrimentos, se propõe a substituição de até 50% da FP por A. platensis que melhorará o desempenho do sistema imunológico não específico das tainhas.Palvras-chave: apoptosis, CD3, estimulante, imune, microalga, peixe, Spirulina.

Association of MHC IIA polymorphisms with disease resistance in Aeromonas hydrophila-challenged Nile tilapia

The major histocompatibility complex (MHC) genes show high polymorphisms in vertebrates depending on animal immunity status. Herein, MHC class IIA gene in Aeromonas hydrophila-challenged Nile tilapia was screened for presence of polymorphisms using sequencing. Twelve nucleotides deletion polymorphism was determined with a PCR product size of 267 bp in the resistant fish and 255 bp in the control and susceptible/diseased fish. Additionally, a non-synonymous right frameshift c.712 T > G (P. 238 * > G) SNP was detected at the stop codon (*). SNP-susceptibility association analysis revealed that fish carrying GG genotype and allele G were high susceptible (risk) for A. hydrophila, and had lower immune response as indicated by significant reduction in non-specific immune parameters (total protein, globulin, IgM, phagocytic activity, phagocytic index, and lysosome activity) and mRNA level of MHC IIA, interleukin 1 beta (IL1β), tumor necrosis factor alfa (TNFα), and toll-like receptor 7 (TLR7) in the spleen and head kidney. Thus, G allele could be considered as a risk (recessive or mutant) allele for c. 712 T > G (P. 238 * > G) SNP and so selection of Nile tilapia with protective allele (T) for this SNP could improve the disease resistant of the fish.

Polysaccharide fraction from the Indian mistletoe, Dendrophthoe falcata (L.f.) Ettingsh enhances innate immunity and disease resistance in Oreochromis niloticus (Linn.)

The polysaccharide fraction (PF) isolated from the hemiparasitic mistletoe, Dendrophthoe falcata (L.f.) Ettingsh (DF) leaves was tested for its immunostimulatory properties in Oreochromis niloticus (Linn.). Different groups of experimental fish were fed for 1, 2 or 3 weeks with three different doses [low (0.01%), mid (0.1%), or high (1%)] of D. falcata polysaccharide fraction (DFPF) - supplemented diet. After every feeding regimen, the fish were assessed for non-specific immunological parameters, immune related gene expression and disease protection. The DFPF treated groups showed significant (P < 0.05) enhancement of non-specific immune parameters. Significant (P < 0.05) upregulation of lysozyme and TNF-α gene expression was observed in DFPF treated groups. In pathogen challenge studies using Aeromonas hydrophila, the DFPF treated groups displayed significant (P < 0.05) decrease in percentage mortality and the consequent increase in relative percent survival (RPS). Supplementation of 1% DFPF in the feed for a week conferred the maximum protection against the virulent pathogen challenge, recording a RPS of 100. These results suggest that DFPF has the potential to be used as an immunostimulating feed additive in finfish aquaculture.

A Review on the Probiotic Effects on Haematological Parameters in Fish

Haematological indices are essential diagnostic tools used to evaluate the health status of fish. Many publications have been stated by different works that qualitative and quantitative variations in haematological parameters; for instance White Blood Cells (WBCs), Red Blood Cells (RBCs), Haematocrit (Hct), Haemoglobin (Hb) content, Mean Corpuscular Haemoglobin Concentration (MCHC), Mean Corpuscular Haemoglobin (MCH) and Mean Corpuscular Volume (MCV) in fish, offer an indication of the health status of the fish. The uses of probiotics as biological control agents in aquaculture have replaced the usage of chemotherapeutics, is an approach in the build-up in aquaculture environments. In the cultured fish, the use of probiotics in monospecies or multispecies forms has been reported to stimulate specific and non-specific immune parameters including lysozyme activities and phagocytic, expression of various cytokines as well as improvement of blood profiles of many fish increasing resistance diseases and to other environmental perturbations such as physiological stressors. Interestingly, many researchers have shown that haematological indices in fish continue to offer a valuable diagnostic tool; and progress is made in establishing a reasonable range of values for blood parameters of different fish species. Also, many interventions have shown that probiotics used in aquaculture have potential in improving blood profiles of fish; although there are not many summarised information regarding the effects of probiotics on haematological parameters in fish. The purpose of this review is to synthesise the influences of probiotics on haematological parameters in fisha.

Immune-enhancing Activity of Potential Probiotic Strains of Lactobacillus Plantarum in the Common Carp (Cyprinus Carpio) Fingerling.

IntroductionImmune-potentiating functions of Lactobacillus plantarum strains in the common carp were evaluated.Material and MethodsFourteen days of feeding fish dry diet supplemented with the bacteria provided parameters of nonspecific humoral immunity (lysozyme, ceruloplasmin, γ-globulin, total protein levels, and serum bactericidal activity) and cellular immunity (pinocytosis, respiratory burst activity, and potential killing activity of organ phagocytes), as well as the proliferative response of organ lymphocytes stimulated with mitogens. The resistance of fish to infection with Aeromonas hydrophila was also determined.ResultsDietary supplementation with L. plantarum had a substantial influence on the activity of organ phagocytes, especially the potential killing activity of head kidney cells. A significant increase in the proliferative activity of LPS-stimulated B lymphocytes and in the levels of γ-globulins and total protein was observed. The supplemented diet conveyed higher resistance than the control diet as the cumulative fish mortalities after infection with A. hydrophila were 65% and 85%, respectively.ConclusionThe results indicate that dietary supplementation with L. plantarum stimulates the antibacterial resistance of common carp and may reinforce defence against bacterial infections, but further studies need to be conducted.

Some Hematological and Non-Specific Immune Responses of Rosehip (Rosa canina) - Fed Russian Sturgeon (Acipenser gueldenstaedtii Brandt &amp; Ratzeburg, 1833) to Mycobacterium salmoniphilum

ABSTRACT In the study, the immunostimulant effects of rosehip (Rosa canina) on the health indicator hematological and non-specific immune parameters of Mycobacterium salmoniphilum-infected sturgeon were investigated. The rosehip was applied in the ratios of R5 (5%), R10 (10%), and R15 (15%) in three repetitions. After a 35-day feeding period, the fish were infected with M. salmoniphilum and analyzed after day 7, when symptoms were observed at elevated levels. Erythrocyte, erythrocyte indices, hemoglobin, hematocrit, leukocyte levels and the non-specific immune parameters including lymphocyte, monocyte, eosinophil, neutrophil, cytokines, phagocytic activity levels were comparatively examined using positive and negative control groups. The evaluations revealed that the RBC, Hb, Hct and WBC counts in the R15 group were significantly higher than those of the C+ group. Moreover, depending on the level of the immune response of the fish, among the immune parameters, significant increases in the lymphocyte, monocyte, cytokine, and phagocytic activity levels were observed in the R15 group. The results showed that the hematological and immune response to M. salmoniphilum infection was stimulated significantly in the 15% rosehip-fed fish. Hence, the effective dose of rosehip in fish was determined to be 15% and rosehip is suggested as an alternative to currently recommended immunostimulants.

Effect of dietary administration of kappa carrageenan extracted from Hypnea musciformis on innate immune response, growth, and survival of Nile tilapia (Oreochromis niloticus)

Immune stimulants are an alternative to antibiotic use and contribute to disease prevention in aquaculture. The effect of dietary administration of kappa carrageenan (Kc), extracted from the red algae Hypnea musciformis, in Nile tilapia (Oreochromis niloticus) was assessed by monitoring weight gain after a 15-day feeding trial. Immunostimulation was inferred by the relative expression of transferrin, interleukin 1β (IL-1β), and growth hormone (GH) in the spleen after 24 h and 15 days of daily administration. The toxic activity of Kc was evaluated in brine shrimp (Artemia salina) nauplii. No significant toxic effects of Kc were observed in A. salina at any dose studied. A positive tendency in growth rate and fish survival values was observed when Kc was administered. Correspondingly, GH, transferrin and IL-1 β levels at day 15 post-treatment were higher in the spleens of fish fed with Kc at 5 g kg−1 relative to non-Kc-treated control fish. Feeding Kc extract from H. musciformis to the fish improved nonspecific immunity parameters and increased survival and growth, but further research, including longer-termed studies, should be conducted before recommendation of Kc supplementation in tilapia diets at commercial scale.

Enhanced protective immunity against spring viremia of carp virus infection can be induced by recombinant subunit vaccine conjugated to single-walled carbon nanotubes

As a successful prevention strategy for controlling the highly contagious and pathogenic disease of spring viremia of carp (SVC), DNA vaccines reported in recent years could trigger protective responses against SVC with the means of injection. However, there remains many concerns and uncertainties related to DNA vaccination as well as injection is labor intensive, costly and not suitable to vaccinate large numbers of fish. Therefore, more efficient and safe prophylactic measures should be urgently investigated. In this research, single-walled carbon nanotubes (SWCNTs) as the candidate SWCNTs-pET32a-G subunit vaccine carrier were administrated via bath (1, 5, 10, 20, 40 mg L−1) or injection (1, 4, 8, 12, 20 μg) in common carp juvenile, and the different immune treatments to induce immunoprotective effect were analyzed. The results showed that SWCNTs-pET32a-G could enter fish body after immersion for 10 h, furthermore, compared to control groups, antibody levels, the non-specific immune parameters (complement activity, superoxide dismutase activity and alkaline phosphatase activity), and immune-related genes (especially the TNF-α and IFNg2b) in vaccinated groups were significantly enhanced in fish immunized with SWCNTs-subunit vaccine. In addition, as a promising carrier, SWCNTs can increase the immune protective effect of naked subunit vaccine by ca. 16% in bath immunization group and by ca. 23% in injection group. This study suggests that SWCNTs-vaccine may represent a potentially efficient immersion vaccine against viral pathogens of fish in the future.

Effect of the EM Bokashi\xae Multimicrobial Probiotic Preparation on the Non-specific Immune Response in Pigs

The aim of the study was to determine the effect of EM Bokashi® on the phagocytic activity of monocytes and granulocytes, oxidative burst, SWC3, and CD11b + CD18+ expression on monocytes and granulocytes, and the serum concentration of cytokine and lysozyme in pig. 60 Sixty female piglets were divided into two groups: I – control and II – experimental. For the experimental group, a probiotic in the form of the preparation EM Bokashi® was added to the basal feed. Flow cytometry was used to determine selected non-specific immune response parameters, intracellular production of hydrogen peroxide by peripheral granulocytes and monocytes, and surface particles in peripheral blood. The EM Bokashi® preparation used in the study was found to increase phagocytic activity mainly in monocytes, with an increased percentage of phagocytic cells in the experimental group. The highest serum lysozyme concentration in the piglets in the experimental group (2.89 mg/dl), was noted on day 42 of the study. In the group of pigs receiving EM Bokashi®, the percentage of phagocytic cells with SWC3 (monocyte/granulocyte) expression was statistically significantly higher than in the control. The increase in the number of cells with SWC3 (monocyte/granulocyte) expression in the peripheral circulation in combination with the greater capacity of the cells for phagocytosis and respiratory burst confirms that the non-specific immune response was modulated in the pigs supplemented with EM Bokashi®.

The effect of time-dependent protein restriction on growth factors, nonspecific immunity, body composition, fatty acids and amino acids in the Siberian sturgeon (Acipenser baerii)

The effect of time-dependent protein restriction (PR) and refeeding were investigated on growth, body composition, fatty acids (FA), amino acids (AA) and nonspecific immune functions in the juvenile Siberian sturgeon (Acipenser baeri; 75 ± 5 g). Test diets included: T1 (control) and T2 fish fed diets containing 400 and 300 g/kg protein respectively during the whole experimental period, T3 (every other day) and T4 (every other week) fish were fed diets containing 300 g/kg protein (PR) and refeeding with diet containing 400 g/kg protein respectively, and T5 fish fed a diet containing 300 g/kg protein for 3 weeks and a diet containing 400 g/kg protein for 5 weeks, were fed to the fish for 56 days by visual satiation. Unlike ration T2 and T5, feeding treatments of T3 and T4 showed an increase in fish growth and body composition (p < 0.05) and they were very close to the control group (p > 0.05). Regarding the fatty acid profile, although the percentage of highly unsaturated fatty acids (HUFA) and polyunsaturated fatty acids (PUFA) declined significantly in the T2 and T5 groups, the saturated fatty acid (SFA) and monounsaturated fatty acids (MUFA) indicated no change among the treatments. In addition, the T2 and T5 groups demonstrated a reduction in essential amino acids (EAA) with a simultaneous increase in nonessential amino acids (NEAAs), which was significant from that of controls and other groups (p < 0.05). In terms of nonspecific immune parameters (serum lysozyme activity and alternate complement activity [ACH50]), treatment 3 has an appropriate result that did not have a significant difference with the control group (p > 0.05), but there was significant difference with other groups (p < 0.05). As a result, the T3 treatment can be used in sturgeon aquaculture practically without any negative impacts on biological or physiological indices.

Non-specific immune responses and intestinal immunity of common carp (Cyprinus carpio ) fed Jujube (Ziziphus jujube ) fruit extract

This study investigated the effects of Jujube (Ziziphus jujube) fruit extract (JFE) as an excellent source of nutrients and phytochemicals on the innate immune responses and expression of genes involved in intestinal immunity of common carp (Cyprinus carpio) fingerlings. Three hundred healthy carps (10.78 ± 0.05 g) fingerlings were randomly allocated to 12 fibre glass tanks (300L; 15 fish per tank) and fed for 8 weeks with experimental diets which contained different levels of JFE (0%, 0.25%, 0.5%, or 1%). Thereafter, serum non-specific immune parameters [total immunoglobulin (Ig) as well as alternative complement (ACH50) and lysozyme activity (SL)] and expression of genes involved in intestinal immunity (lyz, tnf-alpha, il1b, il8, il10, and tgfb) were measured. The results revealed a significant elevation of Ig level in the JFE-fed fish (p < 0.05) over the control fish. However, there was no significant difference among treated groups in case of serum total Ig. The highest levels of SL and ACH50 were observed in fish fed 1% of JFE. Nonetheless, no significant difference was noticed regarding SL and ACH50 of control and other supplemented groups (0.25% and 0.5% JFE). Also, expression of lyz, tnf-alpha, and il1b genes increased significantly (p < 0.05) in JFE-fed fish, in a dose-dependent manner. On the other hand, significant (p < 0.05) down-regulation of il110 and tgfb were noticed in treated groups. The present findings suggested that extraction of Jujube, Z. jujube fruit, possesses beneficial effects on immune responses of common carp.

Comparative study of three predominant gut Bacillus strains and a commercial B. amyloliquefaciens as probiotics on the performance of Clarias gariepinus

The present study was conducted to evaluate the supplementation of three autochthonous Bacillus strains (B. subtilis, B. amyloliquefaciens and B. cereus) and a commercial B. amyloliquefaciensin doses of 1 × 1010 CFU/kg on the growth performance, hematology, antioxidant activities, digestive enzyme levels, immune status and disease resistance of Clarias gariepinus. A total of 300 fish (75.23 ± 1.6 g) were randomly divided into 5 groups (each group was subdivided into 2 subgroups, 30 fish/each). The control group was fed basal diet (D0). Diets D1, D2, D3 and D4were supplemented with B. subtilis, B. amyloliquefaciens, B. cereus and a commercial B. amyloliquefaciens, respectively. During the course of the experiment, D3 showed the best body weight, weight gain, specific growth rate and food conversion ratio. The measured hemogram blood parameters had the highest significant increase in D3. WBCs and monocyte counts had no significant differences among the experimental groups. The serum antioxidant and digestive enzymes were the highest in D3 and were the lowest in D0. After 15 d, the non-specific immune parameters were markedly increased in fish fed probiotic-containing diet compared with the control. After 30 d, the highest significant immune parameters were observed in D3; D1 and D2 had no significant differences in serum lysozyme activity, nitric oxide and IgM compared with D0. Myostatin cDNA levels were adversely affected by probiotic supplements compare with the control. The PACAP expression showed the highest significant value in D3 followed by D1and D4then D2. The relative survival percentages of the Aeromonas sobria challenged C. gariepinus were the highest in D3, D2, D4 and then D1. Among the three isolated Bacillus species, dietary supplementation with the B. cereus had the highest performance in C. gariepinus compared with the commercial B. amyloliquefaciens and the control group.

Effect of dietary yeast nucleotide on antioxidant activity, non-specific immunity, intestinal cytokines, and disease resistance in Nile Tilapia

The present study investigated the effects of dietary supplementation of yeast nucleotides on the hematology, antioxidant activity, non-specific immunity, expression of intestinal cytokines, and disease resistance in Nile Tilapia (Oreochromis niloticus). Fish weighing 42.90 ± 0.14 g were randomly divided into four groups. Each group was set in triplicate (15 fish per replicate). Fish were fed on four dietary levels of yeast nucleotides (NTs) supplemented with the basal diet 0% (control), 0.05%, 0.15%, and 0.25% NTs. Significantly higher total serum protein, albumin, total serum globulin, total WBC counts, and lymphocyte and granulocyte contents were recorded in 0.25% NT group as compared to the control. The albumin/globulin ratio (A:G) showed a considerable decrease in the 0.25% NT group. The non-specific immune parameters; serum killing percentage, lysozyme activity, nitric oxide assay, IgM levels, and anti-protease activity, were significantly higher in the 0.25% NT group as compared to the control. Moreover, a 15-day feeding trial demonstrated improved results in terms of serum lysozyme activity, nitric oxide assay, IgM levels, and anti-protease activity than a 30-day feeding trial. A significant increase in the anti-oxidant status of O. niloticus was noticed, as reflected by increased superoxide dismutase and malondialdehyde activity in the serum of 0.25% NT group compared to the control, while glutathione peroxidase displayed a significant increase in all groups as compared to the control. The intestinal cytokines TGF-β, IL-1β, IL-10β, and TNF-α mRNA levels showed a pattern of 0.25% NT > 0.15% NT > 0.05% NT > 0% NT, as relative to the control Ef-1α levels. The relative survival percentages of fish fed on yeast nucleotide-supplemented diets, as analyzed by exposure to Aeromonas sobria, were significantly better than the control group. In conclusion, dietary yeast nucleotide administration at 0.25% improved blood proteins, leukocytes, antioxidant activity, non-specific immunity, cytokine gene expression, and disease resistance of Nile Tilapia.

Effects of dietary glucose and starch levels on the growth, apparent digestibility, and skin-associated mucosal non-specific immune parameters in juvenile blunt snout bream (Megalobrama amblycephala)

A 10-week feeding trial was performed to evaluate the effects of different types and levels of carbohydrates in growth performance, apparent digestibility coefficients and skin-associated mucosal non-specific immune parameters in blunt snout bream (Megalobrama amblycephala). Fish were randomly fed four diets containing two carbohydrates (glucose and starch) diets and two carbohydrates levels (330 and 440 g kg−1). High carbohydrate levels remarkably increased the weight gain rate (WGR), apparent digestibility of dry matters, protein and carbohydrates, body crud protein content, plasma levels of aspartate transaminase (AST), and skin-associated mucosal levels of immunoglobulin M (IgM), HDL cholesterol, lysozyme (LZM), advanced the transcriptions of mucin 2 (Muc2), mucin 5b (Muc5b) and apolipoprotein A-I (apoA-I), whereas the opposite was true for feed conversion ratio (FCR), plasma levels of IgM, skin-associated mucosal levels of major histocompatibility complex (MHC) and β-Defensins, and the transcriptions of heat shock protein 60 (Hsp60). In addition, carbohydrate types of glucose remarkably increased the survival rate, apparent digestibility of dry matters, protein and carbohydartes, body crud ash, plasma levels of total protein (TP), globulin (GLB), immunoglobulin M (IgM), complement C3 and complement C4 and the transcriptions of Muc5b. Whereas the carbohydrate types of starch remarkably increased viscerosomatic index (VSI), hepatosomatic index (HSI), condition factor (CF), abdominal fat percentage (AFP), apparent digestibility of liquid, advanced the transcriptions of Muc2, apoA-I and heat shock protein 70 (Hsp70). Significant interactions between different types and levels of dietary carbohydrates were also observed in WGR, apparent digestibility of dry matters, protein and liquid, body crud ash, plasma levels of TP, albumin (ALB) and AST, skin-associated mucosal levels of major histocompatibility complex (MHC) and β-Defensins, and the transcriptions of Muc2 and Muc5b. Our results indicate that inclusion of high level of glucose in the diet of blunt snout bream could improve growth performance, nonspecific immunity, and increase the efficiency of protein, which is suggesting that high level of glucose could be used in feed production. However, the proportion of the specific formula of glucose using in feed needs further study.

Influence of vegetable diets on physiological and immune responses to thermal stress in Senegalese sole (Solea senegalensis).

The substitution of fish resources as ingredients for aquafeeds by those based on vegetable sources is needed to ensure aquaculture sustainability in the future. It is known that Senegalese sole (Solea senegalensis) accepts high dietary content of plant ingredients without altering growth or flesh quality parameters. However, scarce information is available regarding the long-term impact of vegetable diets (combining the inclusion of both vegetable protein and oils) on the stress response and immunity of this fish species. This study aims to evaluate the concomitant effect of the extended use of vegetable protein-based diets with fish oil (FO) replacement (0, 50 or 100%) by vegetable oils (VO), on the response to acute (10 min) or prolonged (4 days) stress, induced by thermal shock. Plasma levels of cortisol, glucose and lactate as well as hepatic levels of glucose, glycogen and lactate were evaluated as primary and secondary responses to stress, 6 and 18 months after feeding the experimental diets (6 and 18 MAF). The brain monoaminergic activity in telencephalon and hypothalamus, and non-specific immune parameters were also evaluated. As expected, thermal shock induced an increase in values of plasma parameters related to stress, which was more evident in acute than in prolonged stress. Stress also affected lactate levels in the liver and the values of the alternative complement pathway-ACH50 in the plasma. Dietary substitution of FO induced an effect per se on some parameters such as decreased hepatic glucose and glycogen levels and peroxidase activity in plasma as well enhanced serotonergic activity in brain of non-stressed fish. The results obtained in some parameters indicate that there is an interaction between the use of vegetable diets with the physiological response to thermal stress, as is the case of the hepatic lactate, serotonergic neurotransmission in brain, and the activity of ACH50 in plasma. These results suggest that the inclusion of VO in plant protein based diets point to a slightly inhibited stress response, more evident for an acute than a prolonged stress.

Comparison of the immunomodulators “β-glucan” and “sodium alginate” on the non-specific immune response of the spiny lobster, Panulirus interruptus (Decapoda, Palinura)

Abstract This study mainly investigated whether β-glucan or sodium alginate enhance the non-specific immune response of the spiny lobster, Panulirus interruptus. In experiments, lobsters were fed a diet containing one or the other of these compounds, to determine their effect on non-specific immune parameters in the short term (14 days). The lobsters were then bled to examine variance in total haemocyte count (THC), phenoloxidase activity, superoxide anion (O2−) production, superoxide dismutase (SOD) activity, phagocytic ratio (PR), and phagocytic index (PI). The effects of treatment with various doses of β-glucan and sodium alginate were determined. The results showed that treatment with 1-2 g of β-glucan or 2-4 g of sodium alginate significantly increased THC, O2− production, SOD activity, and PR. In conclusion, the immunomodulators β-glucan and sodium alginate can increase the non-specific immune response in spiny lobsters.

The Effect of Dietary Wheat Gluten Products on Gut Morphology, Non-Specific Immune Parameters, and Allochthonous Intestinal Microbial Population of Juvenile Rainbow Trout (Oncorhynchus mykiss) Fed with a High Plant Protein Diet

Background: Diets for Salmonids contain less fishmeal and more plant (and especially pulse) proteins that can impact gut microbiota, morphology, and non-specific immune system. The objective of the study was to investigate if including 10% of three different types of wheat proteins in a soy-based diet affects in the same manner gut microbiota, morphology and non-specific immune parameters of juvenile rainbow trout. Methods: Over the course of a 66 day nutrition feed trial, triplicate tanks of juvenile rainbow trout (31 fish per tank; initial weight=24.80 ± 0.31 g) were fed three experimental diets containing 10% inclusions of varying types of wheat proteins. Wheat protein inclusions, vital (VWG), hydrolysed (HWG) and a soluble hydrolysed (SWG) were incorporated into a basal feed at the expense of soy protein concentrate (SPC diet). Growth performance was monitored throughout the trial. At the end point intestinal samples were taken for microbial, molecular and histological analysis. Findings: Growth performance was unaffected by 10% dietary inclusions of wheat proteins, especially because growth already achieved high level with the SPC diet, with a feed conversion ratio of 0.99. Modulation of the allochthonous intestinal microbiota at genus level was observed, with increased proportions of Weissella in the 10% VWG treatment compared to the SPC and SWG products. Bacillus relative abundance was significant increased with 10% SWG diet. Leuconostoc was significantly higher with HWG diet. Transcription level expression of TNF-α and Heat Shock Protein 70 (HSP 70) was significantly down-regulated in all wheat protein diets compared to the SPC treatment. A PCA performed on these parameters revealed that SPC diet was significantly associated with the first dimension characterised by high relative abundance of TNF-α, IL10, TGF-β, Glute ST, IL8 and HSP70; while SWG diet was negatively associated with the second dimension which was positively correlated with high relative abundance of IL8 and HSP70 and negatively correlated with relative abundance of IL10 and TGF-β. Increased Intra-epithelial leukocytes (IEL) counts and lamina propria width was observed with 10% VWG and HWG inclusion. Conclusions: All types of wheat proteins are promising plant protein source with the benefits of enhancing growth of potential beneficial bacteria in the intestine, reducing intestinal stress and potentially enhancing the non-specific immune system of rainbow trout fed with a low fishmeal, high pulse diet.

Powder of the White Bottom Mushroom, Agaricus bisporus (Agaricomycetes), Improved Immunomodulatory and Health-Promoting Effects of Lactobacillus casei in Zebrafish (Danio rerio).

This study was conducted to investigate the effects of Lactobacillus casei and Agaricus bisporus administration, alone or in combination, on skin mucus immune parameters and the expression of selected genes related to growth, appetite, mucosal immunity, and antioxidant enzymes in zebrafish (Danio rerio). Zebrafish (n = 600) were randomly stocked in 12 aquariums and assigned to 1 of 4 treatments, which were repeated in triplicate. During a 60-day feeding trial, fish were fed experimental diets: (1) basal diet (control group); (2) basal diet + L. casei (107 colony-forming units/g; Pro group); (3) basal diet + 1% A. bisporus [mushroom powder [MP] group); and (4) basal diet + 1% A. bisporus + L. casei (107 colony-forming units/g) (MP + Pro group). The results demonstrated that oral administration of A. bisporus + L. casei significantly (P < 0.05) upregulated the expression of growth-related genes (gh and igf1). Similar results were observed for expression of mucosal immune-related genes (tnf-alpha, lyz, and il1b) and for antioxidant-related genes (sod, cat) in zebrafish fed A. bisporus + L. casei (P < 0.05). Also, nonspecific skin mucus immune parameters in the MP + Pro group were significantly (P < 0.05) higher than those in the MP, Pro, and control groups. These results also demonstrate the potential of combined administration of A. bisporus and L. casei as a beneficial feed additive in aquaculture.

Transcriptome analysis provides insights into the immune responsive pathways and genes in the head kidney of tiger grouper (Epinephelus fuscoguttatus) fed with Spatholobus suberectus, Phellodendron amurense, or Eclipta prostrata

The tiger grouper, Epinephelus fuscoguttatus, is an economically important fish in Southeast Asia but has been plagued by several diseases. Spatholobus suberectus (S), Phellodendron amurense (P), and Eclipta prostrate (E) are three commonly used Chinese medicinal herbs. Although previous pharmacological and clinical studies indicated that S, P, and E possess a variety of beneficial functions in mammals, little is known about their functions in farmed fish and the underlying molecular mechanism of their actions. Challenge tests in this study showed that after 14 days of diet supplement, all these herbs could effectively enhance the disease resistance of E. fuscoguttatus against Vibrio harveyi. However, the non-specific immune parameters of the herb-supplemented groups were not significantly different from the control group. To further explore the molecular mechanism of herbal immune-regulating effects on E. fuscoguttatus, transcriptome sequencing and RNA-Seq technique were applied on E. fuscoguttatus kidney. De novo transcriptome assembly of E. fuscoguttatus kidney yield 80,014 unigenes, among which, 44,901 (56.12%) were annotated with at least one of the public databases (Nr, Nt, Swiss-Prot, KEGG, COG, GO). Among these, 22,738, 11,700 and 27,457 unigenes were assigned to 57, 25 and 258 categories of GO, COG and KEGG databases, respectively. Using Solexa/Illumina's DGE platform, a total of 231, 186 and 144 putative differentially expressed genes (DEGs) were detected in P, E and S group compared with the control group. GO analysis indicated that in P and E, down-regulated DEGs were dominant in almost every GO term; whereas in S, up-regulated DEGs were more dominant. KEGG pathway analysis revealed that putative DEGs in all three herb groups were obviously enriched in the pathways related to infective diseases and immune system. We also identified a number of immune relative genes and pathways (TLR5, IL8 and MAPK pathway, for instance) associated with P, E and S's regulatory effects on E. fuscoguttatus. This study will enrich the E. fuscoguttatus transcriptome database, contribute to a better understanding of the molecular mechanisms associated with the immunoregulatory activities of Chinese medicinal herbs on teleost and provide valuable information on the prevention of grouper Vibrio diseases using Chinese medicinal herbs.

Effect of stocking density on growth performance, digestive enzyme activities, and nonspecific immune parameters of Palaemonetes sinensis

Palaemonetes sinensis is a new breed of shrimp with great potential for aquaculture, which has been confirmed in our previous production tests. However, there are limited reports about this species and its biological information is scarce. This study describes the effect of stocking density on the growth, digestive enzyme activities, and nonspecific immunity of P. sinensis with an initial average body weight was 0.25 ± 0.02 g. Groups of shrimps were reared at four different initial densities (2.5, 5, 10, and 20 individuals·L−1). After 30 days of culture, the results indicated that the final body weight, weight gain, and specific growth rate were higher in shrimps grown in groups of 10 individuals·L−1 than other groups, but the survival rates of these shrimp were significantly lower than those reared in group of 2.5 or 5 individuals·L−1. The trypsin, amylase, and lipase activities of shrimp significantly decreased with increase in stocking density. Nonspecific immune indicators decreased significantly with increase in density, but there were no significant differences between the 2.5 and 5 individuals·L−1 groups in terms of the total haemocyte count (THC), phenoloxidase activity (PO), lysozyme (LZM), catalase (CAT), and superoxide dismutase (SOD). These results suggest that increasing the stocking density from 2.5 to 5 individuals·L−1 did not affect any of the detected indicators of P. sinensis, but there are shelter in farming mode is better for culture of P. sinensis up to 10 individuals L−1.