Respiratory Burst Activity Research Articles

Effects of pre-treatment with waterborne selenium on redox homeostasis and humoral innate immune parameters in African catfish, Clarias gariepinus (Burchell, 1822), experimentally challenged with Serratia marcescens.

Bacterial infections have been associated with immune dysfunction and oxidative stress in cultured fish species while essential elements could boost immunity and exhibit antioxidant properties in fish. This study was therefore aimed at determining the effects of pre-treatment with waterborne selenium on humoral immunity and redox status of Clarias gariepinus experimentally challenged with Serratia marcescens. Juveniles C. gariepinus were pre-treated with 50µg/L selenium for 14days after which they were challenged with 5 × 103CFU/mL of S. marcescens via oral gavage for 24 or 48h. The control fish were not pre-treated with selenium and not challenged with bacteria. Thereafter, fish were sacrificed, blood collected into EDTA bottles for the determination of plasma nitric oxide levels and respiratory burst, and the liver excised for the determination of reduced glutathione, lipid peroxidation, and activities of catalase, superoxide dismutase, and glutathione peroxidase. Fish that were pre-treated with selenium prior to bacterial challenge (Sel + Bact) had decreased levels of nitric oxide and lipid peroxidation but a significant increase in the levels of reduced glutathione (at 48-h post-infection period only) compared to the fish challenged with bacteria without prior selenium pre-treatment (Bact). The respiratory burst and catalase activity decreased significantly in the Sel + Bact group especially at 48-h post-infection period while the activity of glutathione peroxidase increased significantly in the Sel + Bact group (at 24-h post-infection period only) compared to the Bact group. The results from this study showed that infection with S. marcescens is capable of disrupting the immune system and redox homeostasis in C. gariepinus, while pre-treatment with selenium has the ability to improve the physiological status of fish that were challenged with bacteria probably through its antioxidant properties. HIGHLIGHT: The pre-treatment of Clarias gariepinus to waterborne selenium for 14days improved the redox homeostasis and innate immunity of fish that were experimentally challenged with the bacterium, Serratia marcescens.

Effect of Graded Levels of Dietary Emamectin Benzoate on Immunity, Enzyme Activity, and Withdrawal Period in Labeo rohita Juveniles (Hamilton, 1822)

This study was conducted to evaluate the effect of dietary emamectin benzoate (EB) levels on immune responses, serum enzyme activities, and retention of EB in muscle tissue to establish the withdrawal period in rohu, Labeo rohita juveniles (avg. wt. 18 ± 0.11 g). To ascertain this, 450 healthy L. rohita juveniles were fed with EB in graded doses viz., at 50 (1x), 125 (2.5x), 250 (5x), and 375 (7.5x) μg kg-1 of fish biomass day-1, respectively, in triplicate for 21 days through a basal feed. Upon completion of 21 days, the same experimental fish were fed with basal feed (without EB) for another 14 days to measure the retention of EB in the muscle tissue. Each 7-day interval, five fish were randomly sampled. The results showed that respiratory burst activity, myeloperoxidase activity, bacterial haemagglutination, and haemolysis activities were improved significantly ( p < 0.05 ) in 1x and 2.5x dose fed group from 7th day onwards until 14th day. Few selected enzyme activities viz., LDH and ALP were found to be significantly ( p < 0.05 ) high in the fish fed with EB at 5x and 7.5x dose compared to 1x. The LC-MS/MS study of the experimental fish discloses that EB was retained in muscle tissue at a dose-dependent manner and significantly ( p < 0.05 ) lowest level ( 0.341 ± 0.03 ppb) was retained in the fish fed with 1x dose of EB. Hence, 1x dose of EB may be adhered to treat L. rohita juveniles through feed with 14 days of withdrawal period.

Effects of dietary vitamin C, thyme essential oil, and quercetin on the immunological and antioxidant status of common carp (Cyprinus carpio)

Nowadays, natural bioactive substances are a used in aquaculture feeds to improve fish welfare and therefore increase the quality and sustainability of fish production. The present study was conducted to compare the effects of dietary vitamin C (VC), thyme essential oil (TE), and quercetin (QR) levels on the hematology, and antioxidant and immune parameters of common carp, Cyprinus carpio. Four hundred twenty fish (20.46 ± 0.07 g) were distributed randomly into seven experimental groups (assayed in triplicates). The experimental diets were formulated as follows: CON (0, control); VCL (500 mg VC/kg); VCH (1000 mg VC/kg); TEL (10 g TE/kg); TEH (20 g TE/kg); QRL (200 mg QR/kg); and QRH (800 mg QR/kg). At the end of the 60-day feeding trial, an increase in white blood cells (WBC) was recorded in the treatment groups compared to that of the control (P < 0.05). Hemoglobin (Hb) and mean corpuscular hemoglobin concentration (MCHC) were significantly affected by the TE treatments (P < 0.05). Fish fed the QR diets presented higher levels of hematocrit (Hct) (P < 0.05); as well as enhanced serum and liver antioxidant capacities; such as catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione reductase (GR) (P < 0.05). Malondialdehyde (MDA) activity was significantly lower in fish fed dietary additives (P < 0.05). The treated groups showed significant improvements in serum and intestine immune parameters lysozyme (LYZ), alternative complement pathway (ACH50), total immunoglobulin (Ig), respiratory burst activity (RBA), and myeloperoxidase (MPO) (P < 0.05). Additionally, serum and liver enzyme parameters such Alanine transaminase (ALT), alkaline phosphatase (ALP), and aspartate transaminase (AST) in fish fed the experimental diets were significantly lower than that of fish fed the control diet (P < 0.05). Dietary supplementations had progressive effects on skin mucus LYZ, protease, ALP, Ig, ACH50, and total protein (TP) levels than the untreated group (P < 0.05). The experiment herein successfully demonstrated that dietary VC, TE, and QR stimulate fish antioxidant capacity, as well as humoral and mucosal immune responses, and can be recommended as beneficial feed additives for common carp.

Trh positive strain of Vibrio parahaemolyticus induce immunity by modulating MAPK pathway: A molecular pathogenic insight in immune-related gene regulation

Vibrio parahaemolyticus is a zoonotic bacterium that causes infections in shellfish, fish and higher vertebrates as well as in humans. The Tdh and Trh positive strains of V. parahaemolyticus are generally considered as major virulent strains. The pathogenic mechanisms of Trh positive strain of V. parahaemolyticus are poorly understood. Therefore, in the present study Indian Major Carp, Labeo rohita was intraperitoneally challenged with a Trh positive strain of V. parahaemolyticus below lethal dose 50 (LD50) to understand the innate immune response. A significant upregulation in the respiratory burst activity, myeloperoxidase activity and lysozyme activity of serum was observed in the challenged fishes. However, the serum alpha (α) 2-macro globulin activity and antiprotease activity remained unaltered in the infected fish. The relative expression study of some immune-related genes showed that after the experimental challenge the expression of immune-related genes viz., Toll-like receptor (TLR), Nucleotide-binding oligomerization domain (NOD), Interleukin-1β (IL-β), Interleukin-6 (IL-6), Tumor necrosis factor α (TNFα), Inducible nitric oxide synthase (iNOS), Complement factor 3a (C3a) and Heat shock proteins 70 (Hsp70) was upregulated during infection. Furthermore, overexpression of nuclear factor kappa light chain enhancer of activated B cells (NF-κβ), Myeloid differentiation primary response 88 (MyD88), Mitogen-activated protein kinases (MAPK) and cysteine-aspartic proteases (Casp 1) was also observed after post-infection which clearly indicated that Trh positive V. parahaemolyticus activates MAPK pathway. The present study strengthens the understanding of molecular pathogenesis and provides insights on gene regulation during infection with Trh positive V. parahaemolyticus.

Effect of dietary Spirulina ( Arthrospira platensis ) on the growth performance, immune‐related gene expression and resistance to Vibrio anguillarum in European seabass ( Dicentrarchus labrax )

This research was conducted to reveal the effects of dietary Spirulina (Arthrospira platensis) meal on the growth performance, immune responses and resistance against Vibrio anguillarum in European seabass (Dicentrarchus labrax). In the study, the fish (5.74 ± 0.02 g) were fed with control (C) and three different levels (1%, 2.5% and 5%) of Spirulina meal-containing diets (SP1, SP2.5 and SP5) for 60 days. The adaptive and innate immune responses of fish were determined every 30th day of the study. The results showed that respiratory burst activity (RBA) was significantly elevated on the SP2.5 and SP5 groups on the 30th day of the study. Lysozyme activity (LYS) was increased on the SP1 group on the 30th day and the SP5 group on the 60th day (p < 0.05). Myeloperoxidase activity (MPO) was raised on the 60th day of the SP2.5 and SP5 groups compared with the C (p < 0.05). IL-1β gene expression increased in the kidney and intestine of fish on the 30th day and in the spleen on the 60th day. IL-10 gene expression in the intestine of fish fed the Spirulina-containing diet was elevated at each sampling time relative to the C group (p < 0.05). Elevated IL-6 activity was determined in the kidney and the intestine on all Spirulina-fed groups compared with control at both sampling times. Similar to IL-6, IL-8 gene expressions were elevated in all Spirulina-fed groups (p < 0.05). TNF-α was up-regulated in the kidney and intestine of all Spirulina-fed groups compared with the C group on the 30th day of the study (p < 0.05). TGF-β gene expression was increased in the kidney and intestine of all Spirulina groups compared with the C group on all sampling times. COX-2 gene expression in the kidneys and intestines of fish fed with Spirulina diets was significantly elevated compared with the C diet at days 60th and 30th respectively. Hepcidin gene expression of all groups was elevated in all tissue samples on the 30th day of the study. The survival rate of fish infected with V. anguillarum was higher in all Spirulina-fed groups than in the C group. The feed conversion rate and protein efficiency ratio of fish fed with a 1% Spirulina diet was found to be better than those fed with other diets. These results show that up to the 5% inclusion of Spirulina meal in European seabass diets promotes some growth parameters and supports immunity in fish.

Effects of Dietary Supplementation with Green-Synthesized Zinc Oxide Nanoparticles for Candidiasis Control in Oreochromis niloticus.

Zinc is an essential element for metabolism of Nile tilapia (Oreochromis niloticus). Nanomaterials have important benefits in aquaculture. The present study evaluated the effects of green-synthesized zinc oxide nanoparticles (ZnO-NPs) using Ulva fasciata extract as an anti-fungal agent against Candida albicans (C. albicans) in vitro and in vivo in O. niloticus. A total of 252 apparent healthy O. niloticus (20 ± 0.457g/fish) were randomly allocated into six groups: The 1st group fed on basal diet contaminated with C. albicans 15 × l06 CFU/g diet, the 2nd group fed basal diet only, the 3rd and 5th groups fed the basal diet supplemented with 40 or 60mg/kg ZnO-NPs, respectively, and the 4th and 6th groups fed the basal diet contaminated with C. albicans 15 × l06 CFU/g and concomitantly supplemented with 40 or 60mg/kg ZnO-NPs, respectively. The experiment lasted for 8weeks. The phyco-synthesized ZnO-NPs were characterized by XRD, UV-V, FTIR, TEM, and zeta potential. The anti-fungal activities of ZnO-NPs and the morphological changes to C. albicans cell due to ZnO-NPs were detected. The results revealed that dietary supplementation with the green-synthesized ZnO-NPs significantly improved the growth performance, survival, serum lysozyme activity, phagocytic activity, phagocytic index, respiratory burst activity, expression of immune-related genes (IL-1β, TGF, TNF-α), digestive enzyme activity, and histopathological finding in C. albicans-infected group, with a relative superiority to 40mg/kg feed ZnO-NPs. It could be concluded that supplementing diets with 40mg/kg of phyco-synthesized ZnO-NPs could be considered a better choice for controlling candidiasis in Nile tilapia.

Changes in immune genes expression, immune response, digestive enzymes -antioxidant status, and growth of catla (Catla catla) fed with Astragalus polysaccharides against edwardsiellosis disease

The effect of four level of Astragalus polysaccharides (APs) supplementation diets, (CD: control diet and three experiment diet (E), EA: 100 mg kg−1 APs; EB: 200 mg kg-1 APs; EC: 300 mg kg−1 APs) on growth, changes in haemato-biochemical parameters and metabolic-digestive enzymes, enhancement of antioxidant activity, innate-adaptive immune response, and cytokine gene expression were studied in catla (Catla catla) against Edwardsiella tarda. The healthy and challenged groups fed the CD displayed no mortality, while fish fed EA or EC revealed 10% mortality, but the mortality was only 5% in diet EB. Fish fed diet EB and EC revealed significantly better growth rates and high RBC count during the experimental period. Albumin and globulin levels were significant improved when fish were fed the diet EB and EC from weeks 6–8. The superoxide dismutase (SOD) was significant ameliorated by EB feeding from weeks 4–8. In contrast, serum myeloperoxidase (MPO), catalase (CAT), malondialdehyde (MDA)/lipid peroxidation (LPO), glutathione peroxidase (GPx), respiratory burst activity (RBA), bactericidal action (BCA), serum lysozyme activity (SLA), nitric oxide synthase (NOS), head kidney leukocytes response proliferation (HKLP), hemolytic action (HLA), hydrogen peroxides (H2O2), and immunoglobulin (Ig) were significantly improved from week 6–8. Groups fed the APs enriched diets had significant ameliorated interleukin (IL)-1β and interferon (IFN)-γ mRNA expression after 6 and 8 weeks of feeding. However, IL-10 and major histocompatibility complex (MHC)-1 mRNA expressions were significant enhanced in catla fed all APs diets on week 8. APs enriched diets revealed significant improved tumor necrosis factor (TNF)-α and TNF receptor-associated factor-6 (TRAF6) mRNA expression on week 4, but toll-like receptor-2 (TLR2) and TLR4 mRNA expression were significant enhanced by diet EB and EC after weeks 6 and 8. Similarly, the lysozyme (Lyz)-C and Lyz-G mRNA levels in the head kidney (HK) increased by APs feeding on weeks 6 and 8, whereas the EB diet, the expression of nucleotide binding oligomerization domain-1 (NOD1) was significantly improved on weeks 6 and 8, but NOD2 mRNA expression was only significant enhanced after 8 weeks of diet EB. By feeding healthy catla and E. tarda challenged fish fed diet EB, resulted in significantly increased growth, haemato-biochemical indices, metabolic-digestive enzymes, antioxidant activities, innate-adaptive immune responses, and cytokine gene expression mainly between 6 and 8 weeks.

EFFECTS OF EXTRACTS OF STOCHEOSPERMUM MARGINATUM AND ULVA LACTUCA ON THE HAEMATOLOGICAL AND IMMUNOLOGICAL PARAMETERS ON AEROMONAS HYDROPHILA INFECTED CYPRINUS CARPIO

Objective: Marine algae are the rich source of natural products with pharmacological and biological activities. In the present study the seaweeds Stocheospermum marginatum and Ulva lactuca extracts were used as a immuno stimulants of non-specific immune response in common carp were studied.&#x0D; Methods: The seaweeds Stocheospermum marginatum and Ulva lactuca chosen for the study and were extracted with ethanol. The fishes common carp (Cyprinus carpio) (weight 10±5g)] were divided into five groups. They were infected with A. hydrophila (1.6 × 104 CFU/fish). The infected fishes were injected with seaweeds extracts (0.30 mg) suspended in saline solution. One group was injected only saline (control) and one group was injected with ciprofloxacin (0.30 mg) (standard) suspended in saline. The experiment was carried out for 28 d. In every seven days interval the fishes were injected with seaweed extract and blood parameters of RBC, WBC, HB, Ht, MCV, MCH, and MCHC were recorded.&#x0D; Results: RBC was recorded on 28th day in group 3 (2.86±0.11×106 cells/mm3) followed by group 4 (2.13±0.04×106 cells/mm3). Similarly the WBC values also increase from initial day to final day.&#x0D; The phagocytic assay was same on 28th day in group 3 and group 4 (58.89±1.68). The lysozyme activity was more in group 3 on 28th day 1285±90.92 but the lowest activity recorded in group 4on 28th day 1205±34.35. The respiratory burst activity was higher in group 3 on 28th day 0.184±0.012. Overall results group 3 had the best activity when compared to others.&#x0D; Conclusion: From this study we can understand that the fish injected with seaweed extracts Stocheospermum marginatum and Ulva lactuca seweed as a good immunostimulant. The seaweeds Stoechospermum marginatum had alkaloids, phenol, quinone, saponin, steroid and terpenoid. Ulva lactuca containedalkaloids, sugar, flavenoid, phenol, quinone, steroid and terpenoid. These secondary metabolites were responsible for the immunostumilant activity.

Neutrophil respiratory burst activity is not exaggerated in cystic fibrosis

BackgroundExaggerated neutrophil-dominated inflammation underlies progressive cystic fibrosis (CF) lung disease. Older studies reported a defective respiratory burst in CF, but more recent studies suggest neutrophil function is normal. MethodsWe measured the amount and rate of reactive oxygen species (ROS) during PMA-stimulated respiratory burst activity in children [70 CF, 13 disease controls, 19 health controls] and adults [31 CF, 14 health controls] in neutrophils harvested from peripheral blood. Blood was collected from participants with CF when clinically stable (60 children, 9 adults) and on hospital admission (38 children, 24 adults) and discharge (18 children, 21 adults) for acute pulmonary exacerbations. ResultsWhen clinically stable, children with CF had lower ROS production [median 318,633, 25% 136,810 - 75% 569,523 RLU] than disease controls [median 599,459, 25% 425,566 - 75% 730,527 RLU] and healthy controls [median 534,073, 25% 334,057 - 75% 738,593 RLU] (p = 0.008). The rate of ROS production was also lower (p = 0.029). In neither children nor adults with CF did ROS production increase on hospital admission for acute pulmonary exacerbation, nor fall prior to discharge. There were no associations between ROS production and high-sensitivity C-reactive protein (indicating systemic inflammation) in either children or adults with CF. ConclusionsOur data do not support a role for exaggerated respiratory burst activity contributing to the exaggerated neutrophil-dominated inflammation seen with CF lung disease.

The Effectiveness of Curcuma zedoaria Extract in Enhancing Non Spesific Immune Responses of Tiger Grouper (Epinephelus fuscoguttatus)

The present study was conducted to determine the effect of using turmeric extract (Curcuma zedoaria) on non specific immune of grouper (Epinephelus fuscoguttatus). During the study, fish were fed a diet containing 0, 0.5, 1.0, 2.5 g extract/kg feed twice a day for 14 days. Observations of non-specific immune parameters such as respiratory burst activity, chemiluminescent response, phagocytic activity, superoxidase dismutase (SOD) and lysozyme activity were sampled at 0, 1, 2, 4, 7 and 14 days. The results showed that fish fed C. zedoaria with 0.5 g/kg feed affected non-specific immune responses, and showed significant effect in the short term. On contrary, for long-term administration causes a decrease and inhibition of non-specific cellular defense activity. Thus, this study concluded that the administration of turmeric extract added to the feed can act as an immunostimulant and increase the non-specific immune response in grouper (E. fuscoguttatus).

Phagocytic and oxidative burst activity of neutrophils in type 2 diabetic patients with foot ulcers

Introduction and Aim: Diabetic foot ulcers are common complications seen in diabetic patients. Treatment of this disabling foot sore remains a challenge to health care professionals. This study aimed at evaluating whether the neutrophils from type 2 diabetic patients with foot ulcers present an impairment of phagocytic index and impairment in respiratory burst. We also aimed at understanding whether the impairment in neutrophil phagocytic activity can be alleviated with short course of standard treatment regime for foot ulcers. Methodology: For this case-controled study, 43 participants with type 2 diabetes (18 with foot ulcers and 25 without foot ulcers) were prospectively recruited along with 18 healthy volunteers. Phagocytic activity of neutrophils and respiratory burst of neutrophils was assessed along with ESR, percentage neutrophil counts before and after 2 weeks of standard treatment for foot ulcers. Results: Neutrophils of type 2 diabetic patients (with and without foot ulcers ) showed lower levels of phagocytic index and lower percentage of respiratory burst on comparison with non-diabetic subjects. Furthermore, on receiving treatment for foot ulcers, a significant improvement in neutrophil phagocytic indices were observed, along with improvement in wound ulcer score. Conclusion: Phagocytic activity of the neutrophils is impaired in type 2 diabetics (with and without foot ulcers). Neutrophil phagocytic indices can be improved on glycemic control. Additionally, improvement in neutrophil phagocytic indices after short course treatment for foot ulcers can be useful markers to predict treatment efficacy and in prognosis of diabetic foot ulcers.

Evaluation of potential applications of dietary probiotic (Bacillus licheniformis SB3086): Effect on growth, digestive enzyme activity, hematological, biochemical, and immune response of Tilapia (Oreochromis mossambicus)

The present study was designed to evaluate the dietary effect of dietary supplementation of Bacillus licheniformis on growth, hematological and immune parameters of Oreochromis mossambicus fingerlings. A feeding trial of 8 weeks was carried out, in which fish were fed at a rate of 2% body weight with four experimental diets, including a control diet and three supplemented diets such as, 105, 107 and 109 CFUg-1 respectively. At the termination of feeding experiment, growth related parameters, hematological and immune response of fish were evaluated. Feed conversion ratio (FCR) was significantly decreased, inferring high efficiency in utilizing feed. In similar groups, hematological parameters such as total erythrocyte count, total leukocyte, total serum protein, blood glucose level and hemoglobin count were significantly increased (P&lt;0.05), with higher probiotic concentration. Similarly, digestive enzyme activity of protease, lipase and amylase was also higher in fish fed with increased concentration of probiotic. Diet groups having 109 CFUg-1 of probiotic was observed with elevated immune response, as levels of lysozyme activity, respiratory burst activity and phagocytic activity were significantly higher (P&lt;0.05) in this group as compared to control group. In conclusion, supplementation of diet with Bacillus licheniformis can enhance growth performance, and health status of O. mossambicus.

Stimulation Of Neutrophil Oxidative Burst By Calcium Phosphate Particles With Adsorbed Mucin

Objective — Mucin can promote formation of gallstones via precipitation with calcium phosphate. The proinflammatory effect of mucin-coated particles is still unclear, and our aim was to study the role of mucin sorption in activation of neutrophil respiratory burst. Material and Methods — Polydisperse calcium phosphate nanowires (CP) were prepared from hot gelatin solution and according to scanning electron microscopy (SEM) had the length 1-10 μm and thickness 50-450 nm. CP were incubated in mucin or human serum albumin (HSA) giving CP-Muc and CP-HSA. Their hemolytic activity towards human erythrocytes was assayed, and neutrophil lucigenin- and luminol- chemiluminescence (Luc-CL and Lum-CL) response to CP, CP-HSA and CP-Muc was measured. Cytokine RNA was detected in neutrophils by means of reverse transcription with subsequent real-time PCR. Cytokines (IL-1β, IL-6, IL-8, IL-10) were assessed in cell medium by ELISA. Results and Conclusion — Hemolytic activity of CP was 3.0±0.5%, mucin sorption (0.019 mg/mg) reduced it to 0.24±0.04% (p&lt;0.05) as well as HSA. CP and CP-HSA stimulated neutrophil Lum-CL and Luc-Cl by 2-3 times vs. spontaneous values while for CP-Muc the effect was 10-fold and higher. No increased cytokine gene expression or cytokine secretion was detected after 1h incubation of neutrophils with samples. Obviously, sorption of mucin but not that of HSA stimulated generation of reactive oxygen and halogen species with no increase in cytokine production. Thus, the mucin-coated CP has the potential to contribute to gallstone-associated cholecystitis via oxidative damage of mucosa and epithelium.

Dietary plant pigment on blood-digestive physiology, antioxidant-immune response, and inflammatory gene transcriptional regulation in spotted snakehead (Channa punctata) infected with Pseudomonas aeruginosa

The current study addressed to investigate the effect of lycopene (LYC) on blood physiology, digestive-antioxidant enzyme activity, specific-nonspecific immune response, and inflammatory gene transcriptional regulation (cytokines, heat shock proteins, vitellogenins) in spotted snakehead (Channa punctata) against Pseudomonas aeruginosa. In unchallenged and challenged fish treated with 200 mg LYC enriched diet the growth performance and digestive-antioxidant enzymes increased after 30 days, whereas with inclusion of 100 or 400 mg LYC in the diets, the increase manifested on or after 45 days. No mortality in fish treated with any LYC diet against P. aeruginosa was revealed. In the unchallenged and challenged fish the phagocytic (PC) activity in head kidney (HK) and spleen were significantly enhanced when fed the control diet or other LYC diets, whereas the respiratory burst (RB) activity and nitric oxide (NO) production significantly increased when fed the 200 mg diet for 45 and 60 days. Similarly, the lysozyme (Lyz) activity in the HK and spleen, and total Ig content in serum were significantly higher in both groups fed the 200 mg LYC diet for 15, 45, and 60 days. Heat shock protein (Hsp 70) was significantly improved in the uninfected group fed the 200 mg LYC diet for 45 and 60 days, but Hsp27 did not significantly change among the experimental groups at any time points. TNF-α and IL-6 mRNA pro-inflammatory cytokine expression significantly increased in both groups fed the 200 mg LYC diet after 45 and 60 days, while the IL-12 mRNA expression was moderate in both groups fed the same diet for 60 days. The IL-10 did not significant mRNA expression between groups at any sampling. The iNOS and NF-κB mRNA expression was pointedly high in both groups fed the 200 mg LYC diet on day 45 and 60. Vitellogenin A (VgA) mRNA was significantly higher in the uninfected fish fed the 100 and 200 mg LYC diets for 45 and 60 days, but VgB did not reveal significant difference between the treatment groups at any time points. The present results suggest that supplementation of LYC at 200 mg significantly modulate the blood physiology, digestive-antioxidant enzymes, specific-nonspecific immune parameters, and cytokines, Hsp, and vitellogenins in spotted snakehead against P. aeruginosa.

Influence of quercetin loaded mesoporous silica nanoparticles (QMSNs) on immunity and diseases resistance in Nile tilapia (Oreochromis niloticus)

ABSTRACT The aim of the present study is to scrutinize the potentiality of Quercetin loaded mesoporous silica nanoparticles (QMSNs) to improve the disease resistance and immune response in Nile tilapia (Oreochromis niloticus). The study used five experimental groups of fish with a mean weight of 0.69 ± 0.31 g; three groups were fed quercetin loaded mesoporous silica nanoparticles (QMSNs) incorporated diets (0.25 g kg−1 – QMSNs 0.25, 0.50 g kg−1 – QMSNs 0.50, 1 g kg−1 – QMSNs 1), while the control group was fed an additive-free basal diet. The fifth group was a strict quercetin-only diet (0.25 g kg−1 – QMD). Feeding trial was done for 90 days prior to the experimental challenge with Klebsiella pneumoniae and Streptococcus agalactiae. Dietary quercetin loaded mesoporous silica nanoparticles (QMSNs) especially at 0.50 g kg−1 significantly increased digestive enzymes, phagocytic index, potential killing activity, respiratory burst activity, and Serum antibacterial activity. Furthermore, antioxidant-related genes [superoxide dismutase (SOD) and catalase (CAT)] and metabolic enzymes [serum glutamic oxaloacetic transaminase (AST) and serum glutamic pyruvic transaminase (ALT)] were found to be upregulated in the muscle and hepatopancreases of fish fed with 0.50 g kg−1 QMSNs. Survival rates were significantly higher in the 0.50 g kg−1 QMSNs group at the end of the 15th day challenge period compared to all other treatment groups. As a result, feeding Nile tilapia with 0.50 g kg−1 QMSNs for 90 days may be sufficient to improve fish immune response, antioxidant status, and survival rate against Klebsiella pneumoniae and Streptococcus agalactiae. As a result, quercetin loaded mesoporous silica nanoparticles (QMSNs) can be recommended as a dietary substitute against K.pneumoniae and S. agalactiae in Nile tilapia.

Effects of dietary tea tree oil on the growth, physiological and non-specific immunity response in the giant freshwater prawn (Macrobrachium rosenbergii) under high ammonia stress

This study aimed to investigate the effects of dietary tea tree oil (TTO) on the performance, intestinal antioxidant capacity, and non-specific immunity after ammonia nitrogen stress in Macrobrachium rosenbergii. Six experimental diets were formulated with 0, 25, 50, 100, 200, 400 mg/kg TTO, respectively. A total of 900 prawns (average initial weight, 0.39 ± 0.01 g) were randomly assigned to 6 groups in triplicate in 18 tanks. After an 8-week feeding trial, 20 prawns from each tank were changed with 20 mg/L ammonia stress for 24 h. The results showed that 100 mg/kg TTO significantly increased prawns performance and survival rate compared with the control group. Moreover, 100 and 200 mg/kg TTO significantly improved intestinal antioxidant capabilities by increasing SOD enzyme activities and decreasing MDA levels. In addition, the prawns fed with 100 mg/kg TTO diet showed the highest survival rate under ammonia stress. After ammonia stress, the group of 100 mg/kg TTO significantly improved antioxidant capacity by increasing hemolymph respiratory burst activity, as well as intestinal anti-superoxide anion activity and SOD. Coincidentally, 100 mg/kg TTO significantly upregulated the intestinal relative expression of antioxidant-related genes (peroxiredoxin-5). Further, it was found that 100 mg/kg TTO activated the toll-dorsal pathway in prawns, which performed the similar function as the classic NF-κB pathway by upregulating the TNF-α and IL-1. Finally, 100 mg/kg TTO increased the levels of iNOS activities and NO contents after ammonia stress and enhanced non-specific immunity. The results indicated that 100 mg/kg TTO could significantly improve the M. rosenbergii performance, antioxidant capacity and ammonia stress resistance. We suggested that the mechanisms may be attributed to that TTO enhanced the antioxidant capacity and non-specific immunity of M. rosenbergii via the NF-κB signal pathway.

Different dietary protein levels for Podocnemis unifilis subadult farming: hematological and biochemical assessment

ABSTRACT This study evaluated the physiological responses of subadult yellow-spotted Amazon river turtle, Podocnemis unifilis, to incremental crude protein levels (29%, 32%, 35%, and 39% CP) as extruded commercial feeds. The hematological and plasma biochemical parameters of P. unifilis were analyzed at 60, 120, and 180 days of the feeding trial. The increase in total thrombocyte, leukocyte, lymphocyte, heterophil, and eosinophil numbers, besides high respiratory burst activity showed an improvement in animal immune defense response to incremental protein in diets, acting together to maintain the integrity of the tissues against antigens and infectious agents. Elevated subadult P. unifilis plasma total cholesterol and triglyceride levels observed after increasing the feeding time (until 180 days) with incremented protein levels in artificial diets during captivity are a nutritional warning, related to the condition of being less physically active. Based on these results, periodic physiological evaluations are particularly important to ensure the healthy and adequate nutritional conditions of captive-bred animals, such as maintaining lower stocking densities of animals to avoid stress and, if possible, providing them with fresh food in addition to extruded artificial feed.

Interleukin-1β enhances the expression of two antimicrobial peptides in grass carp (Ctenopharyngodon idella) against Vibrio mimicus via activating NF-κB pathway

Vibrio mimicus (V. mimicus) is a pathogen causing serious vibriosis in aquatic animals. Hepcidin and β-Defensin1 are two important antibacterial peptides (AMPs) with broad-spectrum antibacterial activity in fish. In mammals, some evidences demonstrated that interleukin-1β (IL-1β) primarily promote AMPs expression via activating classical NF-κB pathway, but it still remains unclear in fish. Here, the temporal and spatial expression patterns of grass carp IL-1β (gcIL-1β) gene and two AMPs genes (gchepcidin and gcβ-defensin1) in tissues post-V. mimicus infection and anti-V. mimicus activity of these two AMPs in vitro were detected, showing that V. mimicus infection significantly elevated the mRNA levels of these three genes in the immune-related tissues although their expression patterns were not entirely consistent, and both gcHepcidin and gcβ-Defensin1 possessed anti-V. mimicus activity in vitro. Subsequently, the recombinant gcIL-1β (rgcIL-1β) was expressed prokaryotically in an inclusion body, which could promote proliferation of grass carp head kidney leukocytes (gcHKLs) and enhance respiratory burst activity and phagocytic activity of head kidney macrophages. Stimulation with rgcIL-1β was able to significantly regulate the mRNA expression of key regulatory genes (il-1RI, traf6, tak1, ikkβ, iκBα and p65) involved in the activation of classical NF-κB pathway, and then induce gcTAK1 phosphorylation, promote gcp65 nuclear translocation and enhance endogenous gcIL-1β expression at both mRNA and protein levels, implying NF-κB pathway was activated. More importantly, exogenous rgcIL-1β stimulation also significantly up-regulated both gcHepcidin and gcβ-Defensin1 mRNA levels against V. mimicus, and the regulatory effect was blocked or inhibited by NF-κB inhibitor PDTC. Taken together, our results demonstrated for the first time that grass carp IL-1β stimulation could significantly enhance the expression of these two anti-V.mimicus AMPs via activating classical NF-κB pathway.

Dietary Chlorella vulgaris modulates the performance, antioxidant capacity, innate immunity, and disease resistance capability of Nile tilapia fingerlings fed on plant-based diets

This study assessed the impacts of dietary Chlorella vulgaris (ChV) on the growth, digestive enzymes activity, antioxidant status, immune responses, expression of hepatic cytokines and growth-related genes, and disease resistance capability of Nile tilapia (Oreochromis niloticus) fingerlings fed on plant-based diets. For this purpose, six tested diets were formulated to include 0.0 (control), 2.5, 5, 10, 15, and 20 g ChV/kg diet and were offered to the fish in triplicated groups for 70 days. A dose-dependent increase was observed in feed intake, specific growth rate, and weight gain (%) in ChV-fed fish but feed conversion ratios and survival rates % were not significantly changed among different ChV groups. Significantly higher serum protease, amylase, and lipase enzyme levels were detected in ChV-fed fish than the control group, especially in treatments of 10 – 15 g/kg diet. Feeding the fish with 10–20 g ChV/kg diet markedly increased serum total proteins, total lipids, and globulin levels. Similarly, glutathione peroxidase, superoxide dismutase, and catalase activities as well as serum lysozyme and respiratory burst activities, and total IgM levels were also elevated. On the other hand, lowest malondialdehyde levels were recorded in fish groups fed diets with 10 – 20 g ChV/kg diet compared with the control group. Bactericidal activities against Aeromonas hydrophila, Pseudomonas fluorescens, and Vibrio anguillarum were significantly higher as levels of dietary ChV increased up to 15 and 20 g/kg diet. Dietary ChV also upregulated the transcription of hepatic growth hormone, insulin-like growth factor 1, interleukin-1 beta, and tumor necrosis factor-alpha genes, particularly at 15 – 20 g/kg diet. However, feeding Nile tilapia fingerlings with 15 g ChV/kg diet is adequate to promote the performance and support antioxidant capacity, immune response, and resistance capability to bacterial infections.

Impacts of Amla (Phyllanthus emblica) fruit extract on growth, skin mucosal and serum immunities, and disease resistance of Nile tilapia (Oreochromis niloticus) raised under biofloc system

This study aimed to investigate the effects of Amla (Phyllanthus emblica) fruit extract (AFE) on the growth, skin mucosal and serum immunity, and disease resistance of Nile tilapia (Oreochromis niloticus) against Streptococcus agalactiae. Three hundred fish (10.48 ± 0.56 g fish-1) were distributed in 15 tanks with 20 fish per tank and fed basal diet supplemented with 0, 5, 10, 20, and 40 mg kg-1 AFE for eight weeks. The completed randomized design with three replications was applied. Growth performance, peroxidase, alternative complement, phagocytosis, and respiratory burst activities were determined at weeks 4 and 8. The challenge study was conducted at the end of the experiment. Based on the results, Nile tilapia fed the AFE diets significantly enhanced skin mucus lysozyme and peroxidase activities (P ≤ 0.05) post-feeding. The highest levels were observed in the group that received 20 mg kg-1 of AFE (P ≤ 0.05), whereas the control group presented the lowest levels of lysosome and peroxidase activities. Similarly, incorporation of 20 mg kg-1 of AFE brought about the maximum levels of (P ≤ 0.05) serum lysozyme, peroxidase, alternative complement, phagocytosis, and respiratory burst activities in contrast to the other treatments; whereas fish fed the control diet generated the lowest immune parameter values (P ≤ 0.05). In the challenge study, the Nile tilapia’s relative percent survival (RPS) was 52.38%, 61.90%, 80.95%, and 47.62% in Diet 2, Diet 3, Diet 4, and Diet 5, respectively. Fish fed 20 mg kg-1 AFE showed significantly (P < 0.05) higher RPS, as well as the highest resistance towards S. agalactiae. The inclusion of AFE for 8 weeks resulted in a significant (P < 0.05) enhancement of growth parameters, with the highest growth rate observed in the 20 mg kg-1 AFE group. In conclusion, dietary supplementation with 20 mg AFE kg-1 may be used as a growth promoter and immunostimulant in Nile tilapia aquaculture.