Effect of Achyranthes aspera on the immunity and survival of Labeo rohita infected with Aeromonas hydrophila

Effect of paprika extracts on growth performance, haemolymph chemistry, intestinal microbiota and antioxidant enzyme activities of white-leg shrimp (Litopenaeus vannamei)

This study aims to evaluate the effects of paprika extract on the survival rate, growth performance and stimulation of the innate immune system of Litopenaeus vannamei. In this experiment, 240 healthy shrimp (3.22 ± 0.12 g) were randomly divided into four groups. The shrimp were fed diets with different concentrations of paprika oil extracts (0%, 0.5%, 1% and 2%) for 8 weeks. The results showed that growth performance, urea, uric acid, creatinine, cholesterol levels, aspartate aminotransferase and alkaline phosphatase activities were not significantly affected by adding paprika extract to the shrimp diet (p > 0.05). Diets containing 1% and 0.5% paprika extract showed the highest levels of total protein and triglyceride, respectively (p < 0.05). There was a significant decrease in haemolymph glucose concentration in shrimp-fed diets containing 1% and 2% paprika extract (p < 0.05). Moreover, a diet containing 0.5% paprika extract resulted in the highest levels of total heamocyte count, hyaline cells and large-granular cells in shrimp (p < 0.05). Higher catalase and superoxide dismutase activities were also exhibited in the paprika groups (p < 0.05). Vibrio sp. bacteria were not significantly reduced by paprika extract in the intestines of L. vannamei (p > 0.05). A significant decrease in heterotrophic bacteria was observed with increasing extract concentrations (p < 0.05). The shrimp culture industry can utilize paprika extract as a cost-effective, efficient and environmentally friendly immune stimulant at a concentration of 0.5%.

Dietary supplementation of Chinese herbal medicines enhances the immune response and resistance of rainbow trout (Oncorhynchus mykiss) to infectious hematopoietic necrosis virus

Rainbow trout is a widely farmed economical cold-water fish worldwide, but the prevalence of infectious hematopoietic necrosis virus (IHNV) presents a severe risk to the aquaculture industry, resulting in high mortality and huge economic losses. In this study, the impacts of different concentrations (0, 10, 20, and 30 g/kg) of Chinese herbal medicine mixture (CHMM) on the immune response and resistance of rainbow trout to IHNV infection were evaluated. The results show that CHMM noticeably increased (P < 0.05) T-SOD, CAT, AST, ALT, ACP, and AKP activities and decreased MDA content. NF-κB, TNF-α, IFN-β, IL-1β, JAK1, HSP70, and HSP90 expressions were significantly upregulated (P < 0.05) in all CHMMs, while SOCS2 expression was downregulated (P < 0.05). Following infection with IHNV, feeding rainbow trout with varying amounts of CHMM resulted in noticeably increased (P < 0.05) T-SOD, ACP, and AKP activities and significantly decreased (P < 0.05) MDA content and AST and ALT activities. TNF-α, IFN-β, IL-1β, HSP70, and HSP90 expressions were significantly upregulated (P < 0.05) in all CHMMs, while the expressions of JAK1 and SOCS2 were downregulated. The expression level of the IHNV G protein gene at a dosage of 20 g/kg was notably lower than that of the other CHMM feeding groups. This study provides a solid scientific basis for promoting CHMM as an immunostimulant for boosting antiviral immunity in rainbow trout.

Terminalia arjuna Bark Powder as a Potential Immunomodulator in Labeo rohita: Enhanced Hematological, Adaptive, and Humoral Responses against Bacterial Pathogens and Concordant Liver Histomorphology

This study investigated the dietary immunomodulatory effects of Terminalia arjuna bark powder (TABP) in Labeo rohita, a freshwater fish model. Four iso-nitrogenous and iso-caloric diets containing graded levels of TABP (0, 1, 10, and 15 g/kg were fed to fish for 90 days, followed by a 10 day challenge with pathogenic bacteria Aeromonas hydrophila and Edwardsiella tarda. An integrated biomarker response (IBR) approach assessed the impact of TABP on hematological, adaptive, and humoral immune parameters, along with liver histomorphology. Dietary TABP at 10 g/kg significantly enhanced (p < 0.05) hematological indices (hemoglobin, red blood cell count, hematocrit), specific immune parameters (lysosomal enzyme activity, phagocytosis, respiratory burst), and non-specific immune parameters (serum lysozyme, alternative complement activity), and exhibited improvements in liver architecture consistent with the enhanced immune response. Broken line regression analysis showed 11.5 g/kg to be an optimum dose. However, at 15 g/kg, a compromised trend was observed in some parameters. These findings suggest an optimal dosage range for TABP's immunomodulatory effects. The study highlights the potential of TABP as a natural immunomodulator in fish aquaculture. The improved immune response and concomitant liver health observed in Labeo rohita opens avenues for further research on TABP's applicability in animal health, using fish as a model organism. Additionally, the IBR approach proved effective in evaluating TABP's immunomodulatory properties, paving the way for similar studies on other natural products in aquaculture.

Dietary supplementation of Nile tilapia (Oreochromis niloticus) diets with bay laurel (Laurus nobilis): alleviation of oxidative stress and amelioration of immune response, serum biochemistry, and resistance against Aeromonas hydrophila

Herbal plants can enhance immunity and alleviate oxidative stress in fish. Therefore, the present work was performed to evaluate the effects of bay laurel (Laurus nobilis) on growth, immunity, antioxidant activities, disease resistance, and hematology in Nile tilapia (Oreochromis niloticus). A total of 225 Nile tilapia fingerlings (average weight 15.36 ± 0.04 g) were divided into five treatment groups and fed with bay laurel at 0, 10, 15, 20, and 25 g/kg diet for 90 days. A completely randomized design with three replications was applied. The significantly (p < 0.05) improved weight growth (WG), food conversion ratio (FCR), average daily growth (ADG), protein efficiency ratio (PER), and survival rate were observed in fish fed with bay laurel-supplemented diet at the rate of 15 g/kg. Significantly improved red blood cells (RBCs) count, white blood cells (WBCs), hemoglobin (Hb), and significantly declined alanine aminotransaminase (ALT) and aspartate transaminase (AST) were found in the same diet-fed group. The immune response parameters such as nitro blue tetrazolium (NBT), lysozyme activity, phagocytic activity, total serum protein, serum albumin, serum globulin, and albumin-globulin ratio were found significantly improved at 15 g/kg bay laurel supplemented diet. The improved antioxidant response (catalase, glutathione peroxidase, malondialdehyde, total antioxidant activity) was also observed in the same diet-fed group. Relative percent survival after the fish challenged against Aeromonas hydrophila was significantly (p < 0.05) different. Overall, bay laurel supplementation at a 15 g/kg diet improved the nutritional physiology and immunity and, therefore, could be a potential growth-promoting feed additive for aquaculture development.

Stocking density affects immune and stress-related gene expression of Butter catfish (Ompok bimaculatus) fry in biofloc landscapes

Scientific research into fish wellness is critical, and the concerns about crowding-related stress due to increased stocking density are inevitable. Taking this into consideration, the study defines the physiological signature of Ompok bimaculatus (Butter catfish) in a biofloc system when subjected to varying levels of stocking density. Fish (mean weight = 1.21 g ± 0.08, n = 600) were randomly stocked in 40-L glass aquaria at stocking densities of 0.5 g/L (T1), 1 g/L (T2), 1.5 g/L (T3), and 2 g/L (T4) and fed a 35% protein diet. After the 90-day trial, the physio-biochemical, molecular, and tissue-level changes were assessed. An integrated biomarker response (IBR) analysis for the key stress indicators aided us in better understanding them. There was a significant difference in blood count between T1 and T4 (total erythrocyte count, hemoglobin, and packed cell volume). T1 had higher levels of globulin and total plasma protein, but T2 had higher levels of albumin. Only in T1 did the respiratory burst and lysozyme activity appear to be higher (p < 0.05). Increased stocking densities had a significant impact on the liver function enzymes, GOT and GPT (p < 0.05). In comparison to lower densities (T1 & T2), higher stocking density (T3 & T4) was found to raise glucose and cortisol levels (p < 0.05). Antioxidant enzymes such as catalase, glutathione-S-transferase, and malondialdehyde were found to be more pronounced in lower density tissues (T1). Furthermore, the IBR plots show that lower densities have better health than higher densities. At higher stocking densities, mRNA expression of HSP70, IL-1, and IL-20 increased (p < 0.05) in kidney and liver tissues. The Nrf-2 and Tlr-9 genes were also upregulated. Also, when stocking density was increased, tissue-level histo-architectural changes were more pronounced than when stocking density was kept low. The findings of this study show that the welfare of Butter catfish cultured at high density in biofloc systems suffers from severe stress, and therefore draw more attention to the development of a species-specific standard rearing methodology in the pursuit of a profitable aqua-farming enterprise.

The Synergic Effect of Gut-Derived Probiotic Bacillus cereus SL1 And Ocimum sanctum on Growth, Intestinal Histopathology, Innate Immunity, and Expression of Enzymatic Antioxidant Genes in Fish, Cirrhinus mrigala (Hamilton, 1822)

An effective alternative approach to combat aquaculture challenges is the strategic application of bioresources, which not only mitigate disease ailment but also optimize fish growth. Hence, current research was undertaken to highlight the synergic role of bioresources such as plant immunostimulant Ocimum sanctum along with potent gut-derived probiotic Bacillus cereus strain SL1 (Gen Bank Accession Number: FJ627945.1) on mrigal (Cirrhinus mrigala) growth, antioxidant status, gut histopathology, and immune response. For 90 days, fingerlings (average weight 6.8 ± 0.5 g) were fed on diets having varying concentrations of O. sanctum and B. cereus. After the completion of the feeding trial, various growth, immunity, and histological and antioxidant metrics were evaluated according to standard procedures. In comparison to the control and other treatment groups, T3 group showed a significant (P < 0.05) increase in growth parameters, antioxidant enzymatic activity, and hematological and immunological parameters. In addition to it, supplementation of both B. cereus and O. sanctum also upregulated the antioxidant-related gene expressions, such as hepatic catalase gene by 1.89-3.00 folds, hepatic SOD-1 by 4.46-7.52 folds, and GPx-1of the liver by 1.56-1.95 folds. For 10 days, fingerlings were challenged with the pathogenic bacterium Aeromonas hydrophila (MTCC-1739), and maximum survival rate (77.77%) was reported in fingerlings of T3 treatment. Further histopathological studies of gut tissues affirm that O. sanctum and B. cereus play a synergic role in the protection of digestive organs from the pathogenic bacterium A. hydrophila. These results suggest that O. sanctum and B. cereus synergically improved the growth performance, immunity, antioxidant status, and gut histology of C. mrigala leading to its sustainable culture.

Synthesis of L-methionine-loaded chitosan nanoparticles for controlled release and their in vitro and in vivo evaluation

Therapeutically popular controlled release-enabling technology has forayed into the nutrition sector. Polymer coated forms of L-methionine used in soy protein diets, and its intermediate metabolite, S-adenosyl-L-methionine, used in myriad of medical conditions have proved more efficacious over (highly catabolized) free forms. In this premier study, L-methionine-loaded chitosan nanoparticles (M-NPs) were synthesized using ionic gelation method and their efficacy was evaluated. Biophysical characterization of the NPs was done using a Nanopartica SZ 100 analyser, transmission electron microscopy, and Fourier transform infrared spectroscopy. The M-NPs were spherical and smooth and 218.9 ± 7.4 nm in size and in vitro testing confirmed the controlled release of methionine. A 60-days feeding trial in L. rohita fish fingerlings was conducted. A basal diet suboptimal (0.85%) in methionine was provided with one of the supplements as under: none (control), 0.8% chitosan NPs (0.8% NPs), 1.2% L-methionine (1.2% M) (crystalline free form), 0.6% M-NPs and 1.2% M-NPs. While the addition of 0.6% M-NPs to the basal diet complemented towards meeting the established dietary requirement and resulted in significantly highest (P < 0.05) growth and protein efficiency and sero-immunological test scores (serum total protein, serum globulin, serum albumin: globulin ratio, phagocytic respiratory burst/NBT reduction and lysozyme activity), 1.2% supplementation in either form (free or nano), for being 0.85% excess, was counterproductive. Liver transaminases and dehydrogenases corroborated enhanced growth. It was inferred that part of the methionine requirement in nano form (M-NPs) can confer intended performance and health benefits in animals relying on plant proteins-based diets limiting in this essential amino acid. The study also paves the way for exploring chitosan NPs-based sustained delivery of amino acids in human medical conditions.

Herbal active small molecule as an immunomodulator for potential application on resistance of common carp against SVCV infection

Herbal immunomodulators are an important part of prevention and control on viral diseases in aquaculture because of their propensity to improve immunity in fish. The present study was conducted to evaluate the immunomodulatory effect and antiviral activity of a synthesized derivative (serial number: LML1022) against spring viremia of carp virus (SVCV) infection in vitro and in vivo. The antiviral data suggested that LML1022 at 100 μM significantly inhibited the virus replication in epithelioma papulosum cyprini (EPC) cells, and may completely inhibit the infectivity of SVCV virion particles to fish cells by affecting the viral internalization. The results in the related stability of water environments also demonstrated that LML1022 had an inhibitory half-life of 2.3 d at 15 °C, which would facilitate rapid degradation of LML1022 in aquaculture application. For in vivo study, the survival rate of SVCV-infected common carp was increased 30% at least under continuous oral injection of LML1022 at 2.0 mg/kg for 7 d treatment. Additionally, pretreatment of LML1022 on fish prior to SVCV infection also obviously reduced the viral loads in vivo as well as an improved survival rate, showing that LML1022 was potential as an immunomodulator. As an immune response, LML1022 significantly upregulated the immune-related gene expression including IFN-γ2b, IFN-I, ISG15 and Mx1, indicating that its dietary administration may improve the resistance of common carp against SVCV infection.

The antibacterial activity and immunomodulatory effect of naturally synthesized chitosan and silver nanoparticles against Pseudomonas fluorescence infection in Nile tilapia (Oreochromis niloticus): An in vivo study

A sixty-day feeding trial was conducted to assess the effects of silver nanoparticles (AgNPs) and chitosan nanoparticles (CNPs) on the growth and immunity of Nile tilapia (Oreochromis niloticus), compared with the control group. CNPs and AgNPs were green synthesized and added to a control diet (30% crude protein) at levels of 2.0 g CNPs/kg diet and 1.0 mg AgNPs/kg diet. One hundred and eighty fish (101 ± 3.98 g) were randomly distributed into nine fiberglass tanks (200 cm × 200 cm x 100 cm, twenty fish each) to represent three equal groups (60 fish per group). After one and two months of the feeding trial, parameters of water quality, growth indices, hematology, and liver and kidney biomarkers were evaluated. At the end of the experiment, 10 fish from each group were challenged experimentally via the intraperitoneal injection with Pseudomonas fluorescence and fish mortality was observed for further ten days. Then, specimens from the liver, kidney, spleen, and anterior intestine were examined to assess the histopathological alterations. Incorporating a 2.0 g CNPs/kg diet was a promising growth enhancer; however, a 1.0 mg AgNPs/kg diet had no effects on tilapia performance. Furthermore, AgNPs appeared to reduce water pollution, leading to water filtration via decreasing both total dissolved solids (TDS) and electrical conductivity (EC). A significant role of AgNPs in improving tilapia^'s erythrogram (RBCs number and Hb concentration) was evident. Compared with the control group, both groups of CNPs and AgNPs improved non-specific immune parameters and showed defense effects against P. fluorescence. The fish mortality after P. fluorescence infection in CNPs and AgNPs-fed fish groups revealed significant decreases (P < 0.05) of 10% and 25%; respectively, while the control group exhibited a mortality rate of 40%. The current investigation evoked that using dietary CNPs (2.0 g/kg feed) as an antibacterial agent against P. fluorescence infection in Nile tilapia culture was better than dietary AgNPs (1.0 mg/kg diet) which, induced cells inflammation causing tissues necrosis.

Exopolysaccharides-Mediated ZnO Nanoparticles for the Treatment of Aquatic Diseases in Freshwater Fish Oreochromis mossambicus

Bacterial fish disease outbreaks are a key concern for aquaculture. Complementary feed additives such as immunostimulants can serve as an ideal solution for disease prevention. Herein, we scrutinized the efficacy of exopolysaccharides (EPSs) from probiotic Bacillus licheniformis and EPS-mediated zinc oxide nanoparticles (EPS-ZnO NPs) for a diet to evaluate growth parameters, antioxidant enzyme activities, and immune stimulation together with disease resistance against Aeromonas hydrophila and Vibrio parahaemolyticus in Mozambique tilapia Oreochromis mossambicus. Fish were separated into seven groups, with six experimental groups fed with EPS and EPS-ZnO NPs at 2, 5, and 10 mg/g and a control fed a basal diet. The fish ingesting feed supplemented with EPS and EPS-ZnO NPs at 10 mg/g showed improved growth performance. Cellular and humoral-immunological parameters were tested in serum and mucus after 15 and 30 days of feeding. These parameters were substantially enriched with a 10 mg/g diet (p < 0.05) of EPS and EPS-ZnO NPs in comparison with the control. Furthermore, the EPS and EPS-ZnO NP supplemental diet actively enhanced the antioxidant response (glutathione peroxidase, superoxide dismutase, and catalase). In addition, the supplemental diet of EPS and EPS-ZnO NPs lowered the death rate and improved the disease resistance of O. mossambicus following assessment with A. hydrophila and V. parahaemolyticus at 50 µL. Hence, the overall results suggest that the supplemental diet of EPS and EPS-ZnO NPs might be used to ensure aquaculture feed additives.

Evaluation of Bacillus paramycoides Strains Isolated from Channa Fish sp. on Growth Performance of Labeo rohita Fingerlings Challenged by Fish Pathogen Aeromonas hydrophila MTCC 12301

Probiotics play vital roles in improving growth, survival, and immune responses and inhibit the growth of pathogenic bacteria in freshwater fish. This study was conducted to isolate potential probiotics from Channa punctatus and Channa striatus and to evaluate their effect on Labeo rohita fingerlings. Among the isolates, Bacillus paramycoides PBG9D and BCS10 (1) exhibited antimicrobial activity against the fish pathogen Aeromonas hydrophila. Both strains showed tolerance to acidic and alkaline pH (2, 3, 4, 7, and 9) and bile salts (0.3%) and exhibited strong adhesion capacity. After in-vitro assessment, these strains were evaluated on the growth performances of rohu fingerlings challenged by Aeromonas hydrophila for 4 weeks. The study consisted of six groups, each containing 6 fish. Group (I) was the control, fed a basal diet; group (II) contained a pathogen and was also fed a basal diet; group (III & IV) was given a probiotic supplemented experimental diet; Fourth group (V & VI) contained a pathogen and was given a probiotic supplemented experimental diet. After the 12th day of experiment, rohu fingerlings of pathogen (II) and probiotic + pathogen (V & VI) groups were intraperitoneally injected with 0.1 mL of Aeromonas hydrophila. After 4 weeks, no significant differences in weight gain, weight gain %, and feed conversion ratio were observed in probiotic (III & IV)- fed groups compared to control. However, the specific growth rate was significantly improved in probiotic fed groups compared to other groups. Survival rate and condition factor were significantly similar in all groups. After injection, abnormal swimming, loss of appetite and weight loss were observed in the pathogen (II) group, while no such symptoms were found in the probiotic + pathogen (V & VI)- groups, confirming the effects of probiotics. The overall results of the study revealed that dietary supplementation with Bacillus paramycoides strains could improve the specific growth rate and disease resistance against Aeromonas hydrophila in Labeo rohita.

In Vitro Antibacterial Efficacy of Cymbopogon flexuosus Essential Oil against Aeromonas hydrophila of Fish Origin and in Silico Molecular Docking of the Essential Oil Components against DNA Gyrase-B and Their Drug-Likeness

In aquaculture, diseases caused by the Aeromonads with high antibiotic resistance are among the most common and troublesome diseases. Application of herbs is emerging as a tool in controlling these diseases. Plant extracts besides disease control, favor various physiological activities in fish. In this study, essential oil of Cymbopogon flexuosus (Poaceae family) was studied in vitro for its antibacterial efficacy against two oxytetracycline (OTC) resistant and one sensitive strains of Aeromonas hydrophila. The oil was found rich (86.93 %) in oxygenated terpenoids containing 74.15 % of citral. The oil exhibited dose dependent growth inhibition of the bacteria. Mean MIC value of the oil against the sensitive strain was recorded as 2.0 mg mL^-1 whereas MBC value was recorded as 4.0 mg mL^-1 . The oil was found effective against the OTC resistant isolates with the MIC and MBC values ranging from 2.67-3.33 and 4.0-6.67 mg mL^-1 , respectively. In silico molecular docking of the essential oil components against DNA gyrase-B, a vital macromolecule in bacterial cell, was carried out to computationally asses the efficacy of the oil against the bacteria. Some of the components of the essential oil strongly bonded with the enzyme to inhibit its efficacy. Binding energy of some components of the oil was comparable to that of the conventional antibiotic, OTC. The identified phytochemicals exhibited favorable physicochemical and pharmacokinetic properties and satisfied the rule of five (Ro5).

Dietary Chlorella vulgaris mitigated the adverse effects of Imidacloprid on the growth performance, antioxidant, and immune responses of common carp (Cyprinus carpio)

The use of pesticides to eliminate pests and weeds has raised concerns about water pollution and adverse effects on aquatic organisms, so many efforts have been made to increase the resistance of fish to these pesticides by using a proper nutrition strategy. Therefore, the aim of this study is to investigate the growth performance, antioxidant, and immune responses of fish exposed to Imidacloprid insecticide (C9H10ClN5O2) by different doses of Chlorella vulgaris dry powder to the diet of common carp (Cyprinus carpio). In this study, 600 common carp with a medium weight (18.10±0.2 g; Mean ± SE) were prepared and after adaptation and determination of lethal concentration of Imidacloprid, for 56 days in 6 treatments and each with 3 replications were classified and tested (Control (T1), 5% Chlorella vulgaris dry powder and no pollution (T2), 10% Chlorella vulgaris dry powder and no pollution (T3), No Chlorella vulgaris dry powder and 12.5% LC50 Imidacloprid (T4), 5% Chlorella vulgaris dry powder plus 12.5% LC50 imidacloprid (T5) and 10% Chlorella vulgaris dry powder plus 12.5% LC50 Imidacloprid (T6)). After 96 hours of exposure to distinct concentrations of the insecticide, the total mortality was measured and the Imidacloprid median lethal concentration (LC50) over 96 hours was calculated (266.2 mg/l) using Probit analysis. According to the result, common carp fed T2 had the highest final weight (FW), weight gain (WG), and specific growth rate (SGR), and the lowest feed conversion ratio (FCR) among the groups (P<0.05). Fish in the T2 group had the highest Total proteins, Albumin and Globulin (P<0.05). Fish in the group T4 had the highest Cortisol, Lactate Dehydrogenase (LDH), Alanine Aminotransferase (ALT), Aspartate Aminotransferase (AST), and Alkaline Phosphatase (ALP) levels in the blood, while fish fed T2 and T3 had low values (P<0.05). The Alternative Complement Pathway (ACH50) was significantly higher in T2 and T3 than other groups (P<0.05). Blood total Immunoglobulin (Ig) and Lysozyme activity were high in T2 and T3 groups, and had the lowest values in the T4 group (P<0.05). The Superoxide Dismutase (SOD), Catalase (CAT) and Glutathione Peroxidase (GPx) showed the highest activities in T2 (P<0.05). T4 group had the highest Malondialdehyde (MDA) level, while T2 and T3 groups had the lowest MDA level (P<0.05). The highest Amylase, Protease and Lipase were in the T2 group, while the lowest values were in the T4 group (P<0.05). In conclusion, dietary Chlorella vulgaris protects common carp from Imidacloprid insecticide, since it improved growth performance, antioxidant and immune responses of fish.

Effect of leaves and seeds of Achyranthes aspera as feed supplements on the immunological and stress parameters and related gene expressions of Asian catfish (Clarias batrachus)

The immunostimularory properties of Achyranthes aspera leaves and seeds supplemented feeds were evaluated in Asian catfish, Clarias batrachus (0.352±0.008 g). The experimental feeds contained 0.25% leaves (EFL1), 0.5% leaves (EFL2), 0.5% seeds (EFS) and 0% leaves or seeds (control feed; CF). In CF, leaves and seeds were absent. Fish were immunized with chicken-RBC after 60 days of feeding. The blood and tissue samples were collected on 7th, 14th and 21st days after immunization for various assays. The average weight of magur was significantly higher in EFS compared to the other treatments throughout the study period and EFL2 followed this group. Serum lysozyme level of fish was significantly higher in EFS on 7th and 14th days and in EFS and EFL2 on 21st day after immunization compared to the other treatments. Myeloperoxidase and nitric oxide synthase levels were always significantly higher in EFS diet fed fish compared to other treatments. The highest hemagglutination titer level was found in EFS throughout the study period. Thiobarbituric acid reactive substances (TBARS) and carbonyl protein levels were significantly lower in liver and kidney of enriched diets fed magur compared to CF treatment. TBARS and carbonyl protein levels were minimum in EFS diets fed fish. In EFS and EFL2 treatments, the expressions of TNF-α, iNOS and NF-kB were significantly higher compared to the CF group. A. aspera seeds and leaves showed significant immunostimulatory properties in Asian catfish fry.

Dietary Thymol Improved Growth, Body Composition, Digestive Enzyme Activities, Hematology, Immunity, Antioxidant Defense, and Resistance to Streptococcus iniae in the Rainbow Trout (Oncorhynchus mykiss)

In this study, thymol (TYM) at dietary levels of 0, 1, 1.5, 2, and 2.5 g/kg diet was used to evaluate its effects on growth, digestive performance, immunity, and resistances to the infection induced by Streptococcus iniae in the rainbow trout, Oncorhynchus mykiss. A number of 450 fish (35.8 ± 4.4 g; Mean ± SD) were distributed to 15 tanks (30 fish/tank) in three replicates and fed TYM for 60 days. After feeding period, Fish fed 1.5-2.5 g TYM showed better growth, higher digestive enzyme activity, and body protein content compared to other diets (P < 0.05). Regression analysis indicated a polynomial relationship between growth parameters and dietary TYM levels. Based upon the varied growth parameters, the optimum dietary TYM level was 1.89% for FCR. TYM at dietary levels of 1.5-2.5 g significantly enhanced liver antioxidant enzyme activity [superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT)], immune components in blood [alternative complement activity (C3), total immunoglobulin (Ig), lysozyme activity, bactericidal activity, and total protein], and in mucus [alkaline phosphatase (ALP), protease activity, lysozyme activity, bactericidal activity, and total protein] compared to other diets (P < 0.05). TYM at dietary levels of 2-2.5 g significantly decreased malondialdehyde (MDA) levels compared to other experimental groups (P < 0.05). In addition, use of TYM at dietary levels of 1.5-2.5 g upregulated the expression of the immune-related genes (C3, Lyz, and Ig) (P < 0.05). In contrast, the expression of inflammatory genes, tumor necrosis factor (TNF-α) and Interleukin-8 (IL-8) significantly were downregulated in response to 2-2.5 g TYM (P < 0.05). The hematology of the fish also altered in response to dietary TYM, where the values of corpuscular hemoglobin concentration (MCHC), hemoglobin (Hb), red blood cell (RBC), hematocrit (Hct), and white blood cell (WBC) significantly increased in fish fed 2-2.5 g TYM compared to other diets (P < 0.05). In addition, MCV significantly decreased in response to 2-2.5 g TYM (P < 0.05). After challenge with Streptococcus iniae, the survival rate was significantly higher in fish fed 2-2.5 g TYM compared to other diets (P < 0.05). The results of the present study concluded that TYM in the diet of rainbow trout can improve the fish growth and immunity and increase the resistance of the fish to Streptococcus iniae infection. The results of this study recommend an optimized dietary level of 2-2.5 g TYM for the fish.

Effects of M. oleifera leaf extract on the growth, physiological response and related immune gene expression of crucian carp fingerlings under Aeromonas hydrophila infection

We evaluated the effect of dietary supplementation with Moringa oleifera leaf extract on the resistance to Aeromonas hydrophila infection in crucian carp. The fish were randomly divided into five groups: the basal diet, the basal diet supplied with 0.25% (0.25 M), 0.5% (0.5 M), 0.75% (0.75 M) and 1.0% M. oleifera leaf extract (1.0 M) for 8 weeks. The growth, antioxidant capabilities, related immune genes as well as resistance to A. hydrophila infection were determined. The results showed that compared with the control group, the weight gain, specific growth rate in the group of 0.5% M. oleifera leaf extract, serum superoxide dismutase (SOD), albumin (ALB) and glutathione peroxidase (GSH-Px), the gene expression of hepatopancreas BTB and CNC homolog 1 (Bach1), NF-E2-related factor 2 (Nrf2), peroxidases (PRX) and NADPH oxidase (NOX) in the group of 0.5%-1.0% M. oleifera leaf extract increased, while feed conversion ratio, serum cortisol, red blood cell (RBC), alanine aminotransferase (ALT), malonaldehyde (MDA) decreased in the group of 0.5%-1.0% M. oleifera leaf extract before the stress. After the infection, the group of 0.5% or 0.75% M. oleifera leaf extract also could improve the serum ALB, hepatopancreas Kelch-like-ECH-associated protein 1 (Keap1), Bach1, Nrf2, TOR, PRX and NOX and reduce cortisol compared with the control group. In summary, this study suggested that 0.5% M. oleifera leaf extract inclusion increased the growth performance, even had positive effects on physiological and immune function, and enhanced resistance against pathogenic infections in crucian carp. The optimum level of M. oleifera leaf extract for crucian carp was estimated to be 0.35%-0.48% based on polynomial comparison with FCR and SGR.

Traditional Chinese herb formulas in diet enhance the non-specific immune responses of yellow catfish (Pelteobagrus fulvidraco) and resistance against Aeromonas hydrophila

The effects of a traditional Chinese herbal mixture (TCHM) composed of Glycyrrhiza uralensis, Astragalus membranaceus, Rheum palmatum, Catsia tora and Lonicera japonica on immune response and disease resistance of yellow catfish (Pelteobagrus fulvidraco) were studied. Fish were fed diets containing 0% (control), 1.0%, 3.0% or 5.0% TCHM (w/w) for 28 d. Immune parameters including cytokine genes interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α) and Immunoglobulin M (IgM), acid phosphatase (ACP), alkaline phosphatase (AKP), lysozyme (LZM), catalase (CAT), superoxide dismutase (SOD) and immunoglobulin M (IgM) were measured during the test period. After 28 d of feeding, fish were infected with Aeromonas hydrophila, and mortality was recorded. The TCHM-supplementation diet stimulated ACP, AKP, LZM, CAT, SOD, and IgM activity in serum and induced IL-1β, TNF-α, and IgM mRNA expression in the spleen. All TCHM groups showed reduced mortality after A. hydrophila infection compared to the control group. These results suggest that the TCHM-supplemented diet can improve fish immunity and disease resistance against A. hydrophila.

Role of dietary Spirulina platensis and betaine supplementation on growth, hematological, serum biochemical parameters, antioxidant status, immune responses, and disease resistance in Nile tilapia

Spirulina platensis is, a freshwater microalga, broadly used worldwide. It not only stimulates the immune systems of aquatic organisms but also provides a protein-rich diet and commonly used in the manufacture of aquafeeds. This study was planned to evaluate the growth performance, hepato-renal, and immune response biomarkers of Spirulina and Betaine on Nile tilapia (Oreochromis niloticus) and their protective effect against infection with Aeromonas hydrophila. O. niloticus juveniles (20.22 ± 0.86 g) were divided into four groups (n = 10 per replicate). For 8 weeks, the first and second groups (T_S&T_B) were fed with 0.5% and 0.3% concentrations of Spirulina and Betaine supplemented diets, respectively; the third group (T_SB) was fed with a Spirulina and Betaine mixed diet; the fourth group was fed with a basal diet (without supplementation, T₀), which served as control. Dietary inclusion of Spirulina and Betaine significantly improved (P ˂ 0.05) the weight gain, final weight, and food conversion ratio, especially in the T_S group. The activities of hepatic malonaldehyde were unchanged in T_S & T_SB groups and the muscular significantly decreased (P ˂ 0.05) in the same groups, while both increased in the T_B group; meanwhile, levels of glutathione reductase were significantly upregulated in all treated groups. Serum interleukins, TNF- alpha, and IL-10 levels were also significantly reduced in all treatment groups. A significant protective power against pathogenic Aeromonas infection was evidenced in all treated groups. Findings in this study highlight the reputation of Spirulina and Betaine as immunostimulants and protective agents against A. hydrophila infection in O. niloticus.

Dietary Effect of Padina boergesenii on Growth, Immune Response, and Disease Resistance Against Pseudomonas aeruginosa in Cirrhinus mrigala

In the aquatic environment, seaweeds have the potential to be renewable resources. The current study was designed to assess the impact of seaweed Padina boergesenii incorporated into a basal diet at various concentrations. The phytoconstituents of the seaweeds were characterised by gas chromatography-mass spectrometry. Diets were designed to include elevated levels of 0.5%, 2.5%, 4.5%, and 6.5% of seaweed meal. Significant differences in Cirrhinus mrigala fed with P. boergesenii incorporated into the basal diet for 45 days. The growth parameters (weight gain, specific growth rate), biochemical constituents, and immunological assays were observed. The extract fraction demonstrated effective inhibitory activity against Pseudomonas aeruginosa. As a result, this research suggests that extracts of the seaweed P. boergesenii contain potential bioactive compounds with significant antibiotic activity.

Evaluation of UV-B protective properties of leaves and seeds of Achyranthes aspera in Asian catfish Clarias batrachus (Linn.)

The ultraviolet-B (UV-B) radiation is harmful to the aquatic organisms. The UV-B protective properties of leaves and seeds of herb Achyranthes aspera were evaluated in Clarias batrachus. Fish were fed with four diets-EFL1, EFL2 containing 0.25 and 0.5% leaves, EFS containing 0.5% seeds and control, CF. After 83 days of feeding, fish were exposed to UV-B (157 µW/cm²) for 7 days at the rate of 15 min/day. One batch of fish in each treatment was kept unexposed. Significantly higher final weight was found in EFS followed by EFL2 and EFL1 treatments. It was higher in unexposed fish compared to the exposed ones. Among exposed fish, significantly higher lysozyme was found in EFS and myeloperoxidase in EFS and EFL2 compared to others. Nitric oxide synthase and superoxide dismutase levels were significantly higher in liver and head kidney of EFS diet fed fish compared to others. Thiobarbituric acid reactive substances (TBARS) and carbonyl protein levels were minimum in EFS followed by EFL2. The independent sample t-test showed that nitric oxide synthase was significantly higher and myeloperoxidase and TBARS levels were significantly lower in unexposed group compared to the exposed fish in respective treatment. There were up-regulations of TNF-α, iNOS, NF-kB, BAX, Cytochrome c, SOD-c, Caspase 3, Caspase 9, BCL2 in liver and head kidney of leaves and seeds incorporated diets fed fish compared to control. Supplementation of A. aspera seeds and leaves at 0.5% level in diets gave UV-B protection to the fish.

The effects of dietary immunostimulants on the innate immune response of Indian major carp: A review

Immunostimulants, as feed additives, play an important role in maintaining fish health and enhancing their overall growth by providing resistance against diseases in cultured fish. At the initial stages of life of fish, innate immunity is the essential mechanism in their survival. Later, innate immunity has an instructive role in adapting acquired immune response and homeostasis through different receptor proteins. Several studies have been conducted to analyze the effect of dietary immunostimulants like algae, plant extracts, vitamins, herbs, probiotics, and prebiotics-containing diets in Indian major carps. Many bacterial, fungal and viral pathogens are responsible for high death rates in both wild and cultured fish. It's a major limiting factor for world aquaculture industries. Recognition of invading pathogens by different pathogen recognition receptor plays an important role for the activation of different pathways to initiate protective immune responses. Hence, there is a growing need to control the devastating effects of diseases without recourse to toxic chemicals or antibiotics. Keeping with alternative approaches without using toxic chemicals to control fish diseases in mind, many immunostimulants are used, which enhance immune responses along with their gene expression level through different signaling pathway. The objective of this review is to summarize and evaluate the current knowledge of various immunostimulants and their immune responses in three Indian major carps namely Catla catla, Labeo rohita and Cirrhinus mrigala, which are preferred by the people.

Bacteriophages in the Control of Aeromonas sp. in Aquaculture Systems: An Integrative View

Aeromonas species often cause disease in farmed fish and are responsible for causing significant economic losses worldwide. Although vaccination is the ideal method to prevent infectious diseases, there are still very few vaccines commercially available in the aquaculture field. Currently, aquaculture production relies heavily on antibiotics, contributing to the global issue of the emergence of antimicrobial-resistant bacteria and resistance genes. Therefore, it is essential to develop effective alternatives to antibiotics to reduce their use in aquaculture systems. Bacteriophage (or phage) therapy is a promising approach to control pathogenic bacteria in farmed fish that requires a heavy understanding of certain factors such as the selection of phages, the multiplicity of infection that produces the best bacterial inactivation, bacterial resistance, safety, the host’s immune response, administration route, phage stability and influence. This review focuses on the need to advance phage therapy research in aquaculture, its efficiency as an antimicrobial strategy and the critical aspects to successfully apply this therapy to control Aeromonas infection in fish.

Pharmacological and ameliorative effects of Withania somnifera against cadmium chloride-induced oxidative stress and immune suppression in Nile tilapia, Oreochromis niloticus

This study was carried out to evaluate the effects of dietary supplementation of aqueous extract of Withania somnifera (W. somnifera) against cadmium chloride-induced toxicity in the Nile tilapia, Oreochromis niloticus. Five experimental groups were designed: group (I) was free from cadmium chloride and W. somnifera and served as a control, group (II) was exposed to 1.775 mg L^-1 of cadmium chloride only (which is equivalent to 1/4 96-h LC50), while groups (III), (IV), and (V) were exposed to 1.775 mg cadmium chloride L^-1 with co-supplementation of dietary W. somnifera in doses of 1.0, 2.0, and 3.0 mL kg^-1 body weight (bwt), respectively. The experiment lasted for 4 weeks. In the second and fourth weeks of the experiment, the following indicators were evaluated: hematological (hemogram and blood protein profile), biochemical (activities of serum liver enzymes, namely alanine transaminase (ALT) and aspartate transaminase (AST)), immunological (immunoglobulin M (IgM), serum lysozyme), and tissue antioxidant changes (malondialdehyde (MDA) levels and activities of catalase (CAT) and superoxide dismutase (SOD)). Additionally, gene expressions of glutathione-S-transferase (GST) in the liver were assessed. At the end of the experiment, all fish in all groups were experimentally challenged with Aeromonas hydrophila and the relative protection survival (RPS) was demonstrated. The results revealed that groups exposed to cadmium chloride toxicity and co-supplemented with dietary aqueous extract of W. somnifera at high doses showed significant ameliorative effects in hemogram parameters, total protein, globulin, IgM, and lysozyme against cadmium chloride-induced toxicity compared to the control group and the group exposed to a sublethal dose of cadmium chloride without co-suplemntation of W. somnifera. The results showed also that groups supplemented orally with W. somnifera at high doses have higher antioxidant activities of CAT and SOD and reduction of MDA formation. Levels of gene expressions of GST in the liver were higher in W. somnifera extract-supplemented groups more than those in the group exposed to cadmium chloride-induced toxicity without W. somnifera supplementation. In addition, the results revealed improved RPS with the dietary supply of W. somnifera extract in high doses. In conclusion, this study showed that the dietary supplementation of W. somnifera extract to diets of O. niloticus could be suggested as an effective way to overcome cadmium chloride-induced toxicity because it improves blood parameters and antioxidants, and it can be used as an immunostimulant against the invading bacterial pathogens.

Cytokines Studied in Carp (Cyprinus carpio L.) in Response to Important Diseases

Cytokines belong to the most widely studied group of intracellular molecules involved in the function of the immune system. Their secretion is induced by various infectious stimuli. Cytokine release by host cells has been extensively used as a powerful tool for studying immune reactions in the early stages of viral and bacterial infections. Recently, research attention has shifted to the investigation of cytokine responses using mRNA expression, an essential mechanism related to pathogenic and nonpathogenic-immune stimulants in fish. This review represents the current knowledge of cytokine responses to infectious diseases in the common carp (Cyprinus carpio L.). Given the paucity of literature on cytokine responses to many infections in carp, only select viral diseases, such as koi herpesvirus disease (KHVD), spring viremia of carp (SVC), and carp edema virus disease (CEVD), are discussed. Aeromonas hydrophila is one of the most studied bacterial pathogens associated with cytokine responses in common carp. Therefore, the cytokine-based immunoreactivity raised by this specific bacterial pathogen is also highlighted in this review.

Role of Zingiber officinale and autochthonous probiotic Bacillus coagulans in feeds of Catla catla (Hamilton, 1822) for growth promotion, immunostimulation, histoprotection, and control of DNA damage

Experiment was conducted to assess the impact of ginger (Zingiber officinale) as a dietary supplement with probiotic bacterium Bacillus coagulans on growth performance, hematological parameters, and non-specific immune parameters in Catla catla. An attempt was also made to investigate their effects on histology and extent of DNA damage against pathogenic bacterium Aeromonas hydrophila in C. catla. Ten dietary treatments were designed in triplicate in which five groups of fingerlings fed on diets containing different incorporation level of dried ginger at 0 g kg-1 (C1; basal diet 1 with duckweed as major protein source), 1 g kg-1 (G1), 5 g kg-1 (G2), 10 g kg-1 (G3), and 15 g kg-1 (G4) and other five groups of fingerlings fed on diets (G5-G9) containing different incorporation level of dried ginger at 0, 1, 5, 10, and 15 g kg-1 along with probiotic bacterium B. coagulans @ 3000 CFU ml-1 for 90 days. Results clearly revealed significantly (P < 0.05) high values of weight gain, growth % gain in body weight, specific growth rate (SGR), RBC and WBC count, phagocytic activity, respiratory burst activity, serum protein, and serum bactericidal activity in group of fingerlings fed on ginger supplemented diets which further improved with the inclusion of probiotic with best results in treatment G8. Histopathological study and COMET assay reflected that Z. officinale and probiotics protect extent of DNA damage and the digestive organs from the detrimental effects of pathogenic bacteria affirming their positive role and harmonious effects of probiotic bacterium with Z. officinale-supplemented diets.

The impact of Achyranthes aspera seeds and leaves supplemented feeds on the survival, growth, immune system and specific genes involved in immunostimulation in Clarias batrachus fry challenged with Aeromonas hydrophila in pond conditions

The present study was conducted to evaluate the effect of dietary inclusion of Achyranthes aspera seeds and leaves on the immune system of magur Clarias batrachus challenged with Aeromonas hydrophila in pond conditions. Magur fry (0.51 ± 0.032 g) were cultured in hapas set inside a pond and were fed with three feeds. Two experimental feeds FS1 and FS2 were supplemented with 0.5% seeds and leaves of A. aspera, respectively and FC3 was the control one. After 90 days of feeding, fish were challenged with A. hydrophila. In FC3, 70% fish died within 48 h of challenge, while 25 and 30% mortality were recorded in FS1 and FL2, respectively. The cumulative mortality rates were 70, 45 and 35% in FC3, FL2 and FS1, respectively. The average weight and specific growth rate of magur were significantly higher in FS1 compared to others. Serum lysozyme, myeloperoxidase, nitric oxide synthase and superoxide dismutase levels were significantly higher in FS1 compared to others. Thiobarbituric acid reactive substances and carbonyl protein levels were significantly lower in FS1 compared to others. In liver and head kidney of FS1 and FS2 fed magur, the iNOS, SOD-C, TNF-α, Cytochrome c, Caspase 9 were up-regulated. Caspase 3 was also significantly up-regulated in FS1 and it was followed by FL2 treatment. A. aspera incorporated feeds improved the immune system of fish and gave protection against bacteria even in the pond conditions.

Evaluation of nutritional value of prickly chaff flower (Achyranthes aspera) as fish feed ingredient

The nutritional value of seeds and leaves of Achyranthes aspera as fish feed ingredients was evaluated. The protein and lipid contents were higher in seeds and ash content was higher in leaves. In seeds, total 18 essential and non-essential amino acids were present; total 17 amino acids were found in leaves, cysteine was absent. The essential and non-essential amino acid contents were higher in seeds compared to leaves except, leucine, tryptophan, valine, alanine and tyrosine. Taurine content was higher in leaves. Higher saturated, monounsaturated and n-6 polyunsaturated fatty acids (n-6 PUFA) contents were observed in seeds, whereas, n-3 PUFA level was higher in leaves. In seeds, oleic and linoleic acid levels were 1863.34±9.25 and 3342.05±8.05 mg/100 g, respectively; α- linolenic acids level in leaves was 1058.07±3.71 mg/100 g. Vitamins A, D2, E, B1, B2, B6, B12 and C were present in seeds; vitamins A, D2, E, B2 and B12 were found in leaves. In seeds and leaves, four macro, nine trace and four ultra-trace minerals were found and contents were higher in leaves, except zinc. In seeds and leaves, iron contents were 76.82±4.15 and 293.73±11.40 μg/g, respectively. Thus, seeds and leaves are rich sources of nutrients.

Construction and Characterization of an Aeromonas hydrophila Multi-Gene Deletion Strain and Evaluation of Its Potential as a Live-Attenuated Vaccine in Grass Carp

Aeromonas hydrophila is an important pathogen that causes motile Aeromonas septicemia (MAS) in the aquaculture industry. Aerolysin, hemolysin, serine protease and enterotoxins are considered to be the major virulence factors of A. hydrophila. In this study, we constructed a five-gene (aerA, hly, ahp, alt and ast) deletion mutant strain (named Aeromonas hydrophila five-gene deletion strain, AHFGDS) to observe the biological characteristics and detect its potential as a live-attenuated vaccine candidate. AHFGDS displayed highly attenuated and showed increased susceptibility to fish blood and skin mucus killing, while the wild-type strain ZYAH72 was highly virulent. In zebrafish (Danio rerio), AHFGDS showed a 240-fold higher 50% lethal dose (LD50) than that of the wild-type strain. Immunization with AHFGDS by intracelomic injection or immersion routes both provided grass carp (Ctenopharyngodon idella) significant protection against the challenge of the strain ZYAH72 or J-1 and protected the fish organs from serious injury. Further agglutinating antibody titer test supported that AHFGDS could elicit a host-adaptive immune response. These results suggested the potential of AHFGDS to serve as a live-attenuated vaccine to control A. hydrophila infection in aquaculture.

Protective efficacy of four heat-shock proteins as recombinant vaccines against photobacteriosis in Asian seabass (Lates calcarifer)

Photobacterium damselae subsp. piscicida (Phdp) is the causative agent of photobacteriosis in marine fish and is responsible for huge losses to marine aquaculture worldwide. Efforts have been made to develop a vaccine against this disease. Heat-shock proteins (HSPs) are a family of proteins that are ubiquitous in cellular life. Bacteria produce elevated levels of HSPs as a survival strategy when exposed to stressful environments in a host during infection. This group of proteins are also important antigens that can induce both humoral and cellular immune responses. In this study, four HSPs of Phdp, HSP90, HSP33, HSP70, and DnaJ, were selected for cloning and recombinant expression. Western blotting with rabbit anti-Phdp helped identify rHSP70 and rHSP33 as immunogenic proteins. Asian seabass (Lates calcarifer) immunised with rHSP90, rHSP33, rHSP70, and rDnaJ showed 48.28%, 62.07%, 51.72%, and 31.03% relative percent survival, respectively, after being challenged with Phdp strain AOD105021. High expression levels of immune-related genes and high antibody titres were observed in the rHSP33 group, and the sera of this group also exhibited a high level of bactericidal activity against Phdp. Collectively, our results suggest that HSP33 is a potential candidate for vaccine development against Phdp infection.

Anti-anxiety properties of selected medicinal plants

Exploration of new drugs targeting anxiety treatment is a major concern worldwide. Medicinal plants are being used as a potential source of novel drugs for anxiety disorders. The objective of this review is to provide information about the healing outcomes of anxiety treatment with natural products. Valeriana officinalis, Citrus aurantium, Commelina benghalensis, Achyranthes aspera, Mimosa pudica, Achillea millefolium, Nymphaea alba, Leonurus cardiac, Camellia sinensis, Turnera aphrodisiaca, Crataegus oxyacantha and Piper methysticum showed promising effects on anxiety in animal models. In clinical studies, passion flower, kava, valerian, St John's wort, and ashwagandha showed the most positive results. More studies are needed for the exploration of the anti-anxiety of medicinal plants. In drugs derived from natural sources have explored many components that are playing an essential role in curing anxiety disorders and associated complications.

Cathelicidins enhance protection of channel catfish, Ictalurus punctatus, and channel catfish ♀ × blue catfish, Ictalurus furcatus ♂ hybrid catfish against Edwarsiella ictaluri infection

Cathelicidins are a class of antimicrobial peptides (AMPs) known to possess rapid and direct antimicrobial activities against a variety of microorganisms. Recently identified cathelicidins derived from alligator and sea snake were found to be more effective in inhibiting microbial growth than other AMPs previously characterized. The ability of these two cathelicidins along with the peptides, cecropin and pleurocidin, to protect channel catfish (Ictalurus punctatus, Rafinesque) and hybrid catfish (I. punctatus ♀ × blue catfish, Ictalurus furcatus, Valenciennes ♂) against Edwardsiella ictaluri, one of the most prevalent pathogens affecting commercial catfish industry, was investigated. Cathelicidin-injected fish (50 µg ml^-1  fish^-1 ) that were simultaneously challenged with E. ictaluri through bath immersion at a concentration of ~1 × 10⁶ CFU/ml had increased survival rates compared with other peptide treatments and the infected control. Bacterial numbers were also reduced in the liver and kidney of channel catfish and hybrid catfish in the cathelicidin treatments 24 hr post-infection. After 8 days of challenge, serum was collected to determine immune-related parameters such as bactericidal activity, lysozyme, serum protein, albumin and globulin. These immune-related parameters were significantly elevated in fish injected with the two cathelicidins as compared to other peptide treatments. These results indicate that cathelicidins derived from alligator and sea snake can stimulate immunity and enhance the resistance to E. ictaluri infection in channel catfish and hybrid catfish.

Effect of Green Algae Chaetomorpha antennina Extract on Growth, Modulate Immunity, and Defenses against Edwardsiella tarda Infection in Labeo rohita

Simple Summary

Global demand for macroalgal and microalgal foods is growing, and algae are increasingly being consumed for functional benefits beyond the traditional considerations of nutrition and health. The study was undertaken to know the effect of methanolic extract of Chaetomorpha antennina in fish. The results demonstrated that the betterment of growth, immune system, and resistance to disease against Edwardsiella tarda in Indian major carp, rohu, and Labeo rohita. These findings are useful for development of new feed additive in aquaculture sectors.

Abstract

The current study focused on assessing the outcome of methanol extract of Chaetomorpha antennina (MECA) on the growth performance and immune modulation in both specific and non-specific immune responses through the assessment of neutrophil, serum lysozyme, serum myeloperoxidase, antiprotease, ceruloplasmin, reactive oxygen species (ROS), and reactive nitrogen species (RNS) activity in Labeo rohita (rohu) at 28 days post treatment along with assessment of the disease resistance capacity against Edwardsiella tarda at 30days post immunization. Fishes (n = 144; average weight 50.0 ± 0.23 g) were evenly divided into four treatments, with 12 fishes per tank in triplicates. The MECA was injected intraperitoneally in the fishes at different doses as 0, 25, 75, and 150 mg/kg of the body weight. The results demonstrated that fish treated with MECA have an increased body weight, specific growth rate, and feed conversion ratio (p < 0.05) with respect to the control group. Results suggested that the MECA inclusion can significantly enhance (p < 0.05) the levels of serum lysozyme, neutrophil function, serum antiprotease activity, cellular RNS, and ROS production. Exposure to MECA of 75 mg/kg showed a significantly higher survival percentage against E. tarda disease infection. These results indicate MECA as a stimulant of immunity in L. rohita against E. tarda. The results suggested that MECA is a potent immunostimulant in finfish aquaculture and can offer higher economic welfare.

Exposure to environmentally relevant concentrations of deltamethrin renders the Chinese rare minnow (Gobiocypris rarus) vulnerable to Pseudomonas fluorescens infection

In this study, to assess the immunotoxicity of deltamethrin on fish, adult Chinese rare minnows (Gobiocypris rarus) were exposed to 0.1, 0.3, and 1 μg/L deltamethrin for 28 d. Many immunological parameters and histopathological alterations were determined. The results showed that lymphocyte number was markedly decreased at 0.3 and 1 μg/L treatments, whereas the neutrophil number was strongly increased at 1 μg/L treatments (p < 0.05). Furthermore, lysozyme (LYS), immunoglobulin M (IgM), and complement component 3 (C3) levels at 0.3 and 1 μg/L treatments were markedly reduced, whereas alkaline phosphatase (ALP) activity were marked increased at 1 μg/L treatments (p < 0.05). The transcripts of almost all TLR (Toll-like receptor) signaling pathway-related genes were up-regulated. Histological lesions in the livers, intestines, and gills were observed at all treatments. Then, all remaining fish from controls and deltamethrin-exposed groups were injected with Pseudomonas fluorescens (P. fluorescens) for 48 h. At 24 and 48 h post-injection with P. fluorescens (hpi), the lymphocyte numbers were strongly reduced at 0.3 and 1 μg/L deltamethrin-exposed groups, whereas LYS and C3 levels were strongly reduced at 0.3 and 1 μg/L deltamethrin-exposed groups (p < 0.05). Obvious reduces in IgM levels were also detected at 0.3 and 1 μg/L deltamethrin-exposed groups at 48 hpi (p < 0.05). The transcripts of almost all TLR signaling pathway-related genes were significantly down-regulated, whereas the levels of related microRNAs (miRNAs) were markedly increased at all deltamethrin-exposed groups at 24 and 48 hpi. Moreover, the bacterial load in the liver and the mortality of fish were significantly increased at 1 μg/L deltamethrin-exposed groups at 24 and 48 hpi (p < 0.05). Furthermore, obvious histological damage in the livers, intestines, and gills were observed at all deltamethrin-exposed fish at 48 hpi. Overall, our results demonstrated that environmentally relevant concentration deltamethrin suppressed immunity and rendered the fish vulnerable to P. fluorescens infection, subsequently inducing mortality.

Qualitative Phytochemical Fingerprint and Network Pharmacology Investigation of Achyranthes aspera Linn. Extracts

Achyranthes aspera Linn. (Amaranthaceae), commonly known as the Prickly Chaff flower, is used as herbal medicine in the Ivorian's culture, Africa. Nonetheless, there is currently a paucity of scientific information on A. aspera from the Ivory Coast. Herein, the antioxidant activity of A. aspera extracts (methanol, dichloromethane, ethyl acetate and infusion) as well as the enzymatic inhibitory potentials towards key enzymes in human diseases, namely Alzheimer's disease, (cholinesterases: AchE and BChE), type 2 diabetes (α-glucosidase and α-amylase) and hyperpigmentation (tyrosinase) were assessed. The total phenolic (TPC) and flavonoid (TFC) content was determined using colorimetric methods and the individual compounds were characterized using ultra-high performance liquid chromatography coupled with hybrid quadrupole-Orbitrap high resolution mass spectrometry (UHPLC-HRMS). Furthermore, a network pharmacology analysis was conducted to predict putative targets of identified phenolic compounds. The highest TPC was observed in the infused extract (28.86 ± 0.12 mg GAE/g), while the dichloromethane extract (38.48 ± 1.48 mg RE/g) showed the highest level of TFC. UHPLC-HRMS analysis has revealed an abundance of fatty acids, flavonoids, phenols and acylquinic acids. Among tested extracts, the infused extract displayed the highest free radical quenching, reducing and metal-chelating ability. The extracts (except infusion) were effective as enzyme inhibitors against AChE, while only methanolic and infused extracts showed noteworthy anti-BChE effects. The methanolic extract showed a remarkable antityrosinase effect (56.24 ± 5.05 mg KAE/g), as well. Modest to moderate inhibitory activity was observed against α-amylase (all extracts) and α-glucosidase (only dichloromethane extract). Finally, the network pharmacology analysis suggested the carbonic anhydrase II enzyme as a putative target for explaining, at least in part, the traditional use of A. aspera preparations as diuretic and blood clotting agent. Data amassed herein tend to validate the use of A. aspera in traditional medicine, as well as act as a stepping stone for further studies in the quest for novel phytopharmaceuticals. In this context, it is desirable that this study will contribute to the validation of the traditional uses of this plant in the African herbal medicine, and to the valorization of the whole chain production of A. aspera, as a local and sustainable botanical resource.

Transgenerational disrupting impacts of atrazine in zebrafish: Beneficial effects of dietary spirulina

In a range of fish species, offspring sustainability is much dependent to their mother's investment into the egg yolk. A healthy environment helps broodfish to produce normal quality offspring. However, deviation from optimal conditions can disturb body functions that effect the next generation. Here, zebrafish (Danio rerio) was employed to investigate the transgenerational impacts of an immunotoxic and endocrine disruptor, atrazine (AZ). In addition, the possible ameliorated effects of a nutraceutical, Arthrospira platensis (spirulina- SP), was considered. Adult females were either exposed to 0 (Cn), 5 (AZ5), and 50 (AZ50) μg/L AZ or fed SP-supplemented diet (10 g/kg; SP). In combination treatments, fish were also exposed to AZ and fed SP (SP-AZ5 and SP-AZ50). Embryos were obtained after 28 d of exposure. Exposure to AZ50 caused females to produce eggs with significantly lower fertilization and hatching. No changes were observed in the concentrations of thyroid hormones. AZ significantly increased cortisol response and reduced levels of immunoglobulin, lysozyme and complement activities in females and their offspring. SP-AZ5 and SP-AZ50 females, however, resisted to the toxic effects of AZ, produced embryos with lower cortisol content and higher immunity competence. Bactericidal activity of the embryos also showed the transgenerational antimicrobial effects of SP along with the AZ immunotoxicity. Overall, these results indicate that AZ could have long lasting toxic effects on fish, and that dietary SP-supplementation could ameliorate AZ induced transgenerational toxic effects.

In vivo and in vitro antimicrobial activity of phytol, a diterpene molecule, isolated and characterized from Adhatoda vasica Nees. (Acanthaceae), to control severe bacterial disease of ornamental fish, Carassius auratus, caused by Bacillus licheniformis PKBMS16

Bacillus licheniformis, a pathogenic new strain of bacteria is considered as the main cause of high mortalities and economic losses among the ornamental fish farms of India. The present study aimed to investigate the anti-bacterial and Immunostimulant activity of three selected Indian medicinal plants, Allium sativum, Adhatoda vasica and Centella asiatica for treating Bacillus licheniformis PKBMS₁₆ by subsequent experimental and clinical trials using different organic polar and non-polar solvents. The antimicrobial and Immunostimulant activity of methanolic crude extracts of Adhatoda vasica was fractions and active constituents was further characterized by chromatography and mass spectroscopy studies using FTIR, ¹HNMR and ^13c NMR to identify as well as to determine the nature of the pure compound which is phytol (C₂₀H₄₀O), a diterpene alcohol with a molecular weight of m/z 297. In order to study the in vivo anti-pathogenic influence of the biologically active compounds, phytol were incorporated to the artificial diets at the concentration of 2, 5 and 8 mg/kg and fed to the1.0 × 10⁵ CFU/ml of Bacillus licheniformis PKBMS₁₆ injected experimentally challenged ornamental goldfish Carassius auratus for twenty days. Phytol treated group significantly (P < 0.01 and P < 0.05) reduced the rate of fish mortality. After the termination of survivability assay the estimation of hemato-biochemical parameters have been performed and revealed the significant recovery of health condition on 20th days post treatment. Therefore, the present study concluded that the low toxicity along with high bioactivity and tolerance by lower vertebrate supports the potential of phytol as a new compound for inducing fish immunity.

Influence of a diet containing plant ingredients at different levels on growth performance, carcass biochemical composition, and blood parameters in Indian major carps grown in polyculture earthen ponds

The effect of feeding levels of plant ingredient-based diet on growth, body composition, and serological constituents of Indian major carps was determined in pond culture condition. Juveniles of Indian major carps (IMCs), Catla catla (catla, 65.87 ± 2.45 g), Labeo rohita (rohu, 64.67 ± 2.15 g), and Cirrhinus mrigala (mrigal, 39.58 ± 3.49 g) were fed 1%, 1.5%, 2%, and 2.5% of the body weight for a period of 150 days. At the end, the total production was significantly higher at 2.0% feeding level and did not change thereafter. The nutrient utilization parameters were significantly (P < 0.001) affected by the feeding level and decreased both linearly and quadratically with the higher level of feed. The SGR in terms of wet weight, dry weight, protein, and lipid increased up to 2% feeding level and plateaued thereafter. The whole body crude protein content of all the three species was the lowest at 1% feeding level and the whole body lipid content increased with increased feeding levels. Tissue protein gain and lipid gain of IMCs were the highest at 2% feeding level. Blood parameter did not indicate any disease or stress condition due to feeding treatments. Considering the growth and nutrition utilization and health of fish, it can be concluded that optimum feeding level of all plant ingredient-based feed of IMC could be 2% of the body weight in pond culture condition.

Biofloc technology improves growth, innate immune responses, oxidative status, and resistance to acute stress in common carp (Cyprinus carpio) under high stocking density

This study aimed to evaluate the effects of biofloc technology (BFT) on the performance of common carp under high stocking density. Fish (8.41 ± 0.44 g) were stocked into 12 tanks (70 L) in a 2 × 2 factorial design consisting of clear water (CW) and BFT systems at two stocking densities. Fish were divided into four groups according to culture system and stocking density: CW6 (clear water, 6 kg m^-3), CW12 (clear water, 12 kg m^-3), BFT6 (biofloc, 6 kg m^-3), and BFT12 (biofloc, 12 kg m^-3). After 49 days, the fish were exposed to acute crowding stress (40 kg m^-3) for 7 days to evaluate the fish performance to additional stressors. Total ammonia nitrogen (TAN) concentration was significantly lower in BFT groups at the end of the trial. The growth of fish was significantly higher and the feed conversion ratio was lower in BFT groups. The final density of fish was highest in BFT12 group (25.41 ± 0.48 kg m^-3). The amylase and protease activities in BFT groups were significantly higher than the CW12 group. The highest serum catalase, superoxide dismutase, and glutathione peroxidase activities, and malondialdehyde content (3.07 ± 0.16 nmol mg^-1 protein) were observed in CW12 group. Serum LDL, cholesterol, triglyceride, total protein, and albumin levels were significantly higher in CW6 and BFT6 groups, followed by BFT12 group, and lowest in CW12 group. Serum globulin level was lowest in CW12 group (0.68 ± 0.06 g dL^-1). After 49 days, serum lysozyme, alternative complement (ACH₅₀) and ALP activities were significantly higher and serum cortisol and glucose levels and ALT and AST activities were lower in BFT groups than the CW12 group. After 7 days of acute stress, serum lysozyme activities were significantly lower and ACH₅₀ and ALP activities were higher in BFT groups than the CW12 group. Also, fish in CW12 group were more sensitive to the acute stressor, showing higher cortisol and lower glucose levels. Overall, biofloc had the anti-stress effect, and the culture of common carp in the biofloc system at a stocking density of 12 kg m^-3 could be recommended. BFT can also exert beneficial effects on the welfare of fish subjected to acute stress.

Antibacterial activity of Oliveria decumbens against Streptococcus iniae in Nile tilapia (Oreochromis niloticus) and its effects on serum and mucosal immunity and antioxidant status

The aims of this study were to investigate the antibacterial, immunostimulatory and antioxidant properties of different derivatives of Oliveria decumbens, in vitro and in vivo. The GC-MS spectrometry analysis showed γ-terpinene as the most frequent compound in essential oil, whereas carvacrol and thymol were the most common ones in aromatic water. Plant essential oil and hydroethanolic extract showed a positive in vitro bactericidal activity against Streptococcus iniae as evaluated by disc diffusion, minimum inhibitory concentration and minimum bactericidal concentration methods. Also, in vivo resistance against S. iniae and immune and antioxidant responses of Nile tilapia (Oreochromis niloticus) were assayed after 60 days treatment with O. decumbens derivatives. Plant hydroethanolic extract and essential oil and their 1:1 combination were added to diet at 0 (negative control), 0.01, 0.1 and 1% (w:w). The plant aromatic water at doses of 0.0312, 0.0625 and 0.1250% were also used as bath treatment. The results showed that aromatic water at lowest dose was more effective than other treatments in increment of fish resistance against S. iniae (7.14% mortality in comparison with 50% mortalities in control fish) and modulation of post-challenge respiratory burst activity. The bactericidal activity and biochemical contents of skin mucus did not change significantly among treatments. The levels of superoxide dismutase and catalase antioxidant enzymes activities in spleen tissue were significantly higher in treatments received extract, essential oils and their combination in comparison to other groups, while treatments did not affect peroxidase level. In conclusion, administration of different derivatives of Oliveria decumbens showed remarkable antibacterial activity against streptococcosis and enhanced antioxidant status and post-challenge immunity in Nile tilapia.

Behavioral and immunotoxic effects of Prograf® (tacrolimus) in the male Siamese fighting fish

Siamese fighting fish (Betta splendens) has been extensively exploited in the behavioral and physiological toxicology studies of drugs. Tacrolimus is an immunosuppressant drug largely used in liver and renal transplantations. Here we found that a 7-day exposure of male B. splendens to concentrations of 0.05 and 0.1 µg/mL Prograf® (tacrolimus) caused alterations in aggression and immunity indexes. Tacrolimus exposed fish presented lower opercular display in a mirror test which is indicative of reduced aggression. In addition, serum levels of lysozyme, IgM, alternative complement, and bactericidal activity of subjects exposed to 0.1 µg/mL tacrolimus were lower than those from the control treatment. These results showed the behavioral impairment and immunotoxic impacts of tacrolimus in a model of aquatic toxicology. The results suggest fishes provide a possible model for better understanding of the drug action in vertebrates, and possible consequences for the environment via its effects on non-target organisms in an ecotoxicology context.

Effect of in-situ and ex-situ biofloc on immune response of Genetically Improved Farmed Tilapia

The present study is aimed to investigate the effect of biofloc intake on Genetically Improved Farmed Tilapia (GIFT), developed within the system and its influence as feed supplementation on water quality, growth performance, immunological parameters, antioxidant status, immune gene expression, and its resistance to Aeromonas hydrophila infection. GIFT Tilapia juveniles of 5.1 g (±0.05) were stocked at a density of 15/m³ in lined ponds of 300 m² in triplicates for 180 days. The experimental groups consisted of T1-biofloc developed within the culture systems (insitu), T2-biofloc supplementation in fish feed (exsitu) and C- Control without biofloc. Distillery Spent wash was used as a carbon source to maintain the C/N ratio of 10:1 for floc development in T1. Free CO_2, pH, BOD, dissolved oxygen, alkalinity, Calcium and Magnesium ions, Nitrate, Nitrite and ammonia were found to be significantly different between the treatments and control throughout the experiment. The immunological (Serum protein, Respiratory burst test (RBT) and Myeloperoxidase) and antioxidant indicators (Glucose, Superoxide dismutase (SOD) and catalase) were found to be significantly higher in T1 at the end of the trial. Increased weight gain, specific growth rate, survival and decreased feed conversion ratio was found in T1 when compared with the other experimental groups. Real time quantitative PCR analysis revealed that there was no folded expression of the immunological genes such as Metallothionein gene, cathepsin L, Toll like receptor 7, Interleukin 1 β and Tumour necrosis factor α in liver and intestine for both control and treatment. However, the upregulated expression of targeted genes except tumour necrosis factor α was found in head kidney of T1. At the end of the study, GIFT Tilapia when infected with Aeromonas hydrophila showed an improved immune response in T1 and T2 with lesser signs of infection than Control. The findings of the present study affirmed the importance of biofloc technology in triggering the immunomodulatory response of GIFT Tilapia with its upregulated immune gene expression and its role as an antimicrobial agent against Aeromonas hydrophila. This study suggests the adoption of in-situ (T1) based biofloc method to obtain better performance of GIFT Tilapia culture.

Possible effect of hala extract (Pandanus tectorius) on immune status, anti-tumour and resistance to Yersinia ruckeri infection in rainbow trout (Oncorhynchus mykiss)

The possible effect of dietary administration of hala extract (Pandanus tectorius) on rainbow trout (Oncorhynchus mykiss) immune status as well as its effect as an anti-tumour agent was studied. Fish were divided into 4 groups before feeding with commercial diet (0%, control; 0.5%, 1% and 2% of hala extract) for 2 weeks. The effect of diet on the humoral immune parameters, ie total protein, myeloperoxidase content, antiproteases, lysozyme and bactericidal activities were studied. Also, the effect of the diets on the expression of some immune-related genes in rainbow trout head-kidney (TNF, LYZ2, IL-8 and CD-4) as well as tumour suppressor gene (WT-1a) was investigated. At the end of the feeding trial fish groups were challenged with Yersinia ruckeri. The results demonstrated enhancement in all the immune parameters in fish fed hala extract diets compared to control fish especially with the highest dose (2%) which recorded the highest significant increase (p < 0.05) in some parameters (total protein, myeloperoxidase content, antiproteases, and bactericidal activities) compared to the control. The results obtained from challenge with Y. ruckeri revealed reduction in the mortalities in fish groups fed with 1% and 2% doses of hala extract. Feeding with hala extract provoked upregulation in all immune- related genes. Again, the highest dose of hala extract showed a significant upregulation in WT1a expression (p < 0.05). The current study suggest that the hala extract, especially the highest dose, could be considered a good food additive to improve the immune status, resist tumour formation and to resist or control infectious diseases of rainbow trout.

Traditional Chinese Medicine Enhances Growth, Immune Response, and Resistance to Streptococcus agalactiae in Nile Tilapia

Herbal supplements are suitable for improving fish health and combating diseases in fish culture. However, the mechanism of action of many herbal mixtures remains unclear. This study was conducted to evaluate the effects of traditional Chinese medicine (TCM; a mix of Astragalus membranaceus, Angelica sinensis, and Crataegus hupehensis at a ratio of 1:1:1 on a weight basis) on growth, immune response, and disease resistance in Nile tilapia Oreochromis niloticus. Experimental fish (mean ± SE weight = 57 ± 1 g) were divided into two groups: a control group and a TCM (10 g/kg) group. After 4 weeks of the experimental trial, a significant increase in weight gain and specific growth rate and a lower feed conversion ratio were observed in fish fed a TCM-supplemented diet compared with control fish. Similarly, the immune response of Nile Tilapia in the TCM group showed enhanced lysozyme, superoxide dismutase, catalase, and immunoglobulin levels compared with the control fish. In comparison with the control, fish fed TCM showed significant up-regulation of β-defensin, lysozyme, heat shock protein 70, superoxide dismutase, and catalase genes in the intestine and head-kidney tissues. After a Streptococcus agalactiae challenge, survival of Nile Tilapia in the TCM group was 70% compared with 35% in the control. These results indicate that the TCM mixture in this study can elevate the immune response and disease resistance of Nile Tilapia.

Validation of growth enhancing, immunostimulatory and disease resistance properties of Achyranthes aspera in Labeo rohita fry in pond conditions

The immunostimulatory and disease resistance properties of herb Achyranthes aspera L. (Amaranthaceae) were evaluated in rohu Labeo rohita in pond. Rohu fry (1.9 ± 0.08 g) were cultured in hapas (25 hapa⁻¹) set inside a pond and were fed with two experimental diets containing 0.5% seeds (D1) and leaves (D2) of A. aspera and control diet (D3). Fish were challenged with Aeromonas hydrophila after 80 days. The cumulative mortality rate of fish was significantly (P < 0.05) higher in D3 (28–48%) compared to others. Average weight was significantly (P < 0.05) higher in D1 (6.5–12.5%) compared to other treatments. Myeloperoxidase and nitric oxide synthase levels were significantly (P < 0.05) higher in D1 and D2 compared to D3. Thiobarbituric acid reactive substances and carbonyl protein levels were significantly (P < 0.05) lower in hepatopancreas and kidney of D1 compared to others. In hepatopancreas, the expressions of lysozyme C, loysozyme G, TNF-α, IL-10 and IL-1β were significantly (P < 0.05) higher in D1 compared to others. This treatment was followed by D2. In kidney, lysozyme G and TNF-α levels were significantly (P < 0.05) higher in D1 and D2 compared to D3. Whereas, IL-10 and IL-1β were significantly (P < 0.05) down-regulated and up-regulated, respectively in kidney of D2. There was up-regulation (P < 0.05) of TLR-4 in hepatopancreas and kidney of D1 and D2 diets fed rohu, respectively compared to others.

Effects of Achyranthes bidentata Polysaccharides on Intestinal Morphology, Immune Response, and Gut Microbiome in Yellow Broiler Chickens Challenged with Escherichia coli K88

The present study was conducted to investigate the effects of dietary Achyranthes bidentata polysaccharide (ABPS) supplementation on performance, immune response, intestinal mucosal morphology, and gut microbiome in yellow-feathered broilers challenged with Escherichia coli K88. A 2 × 2 factorial design was used for the trial. Two hundred and forty one-day-old female broilers were randomly assigned to four treatments: (1) negative-control broilers were fed by a basal diet and saline (NG); (2) positive-control broilers were fed by a basal diet and orally challenged with 10⁸ CFU E. coli K88 (CNG); (3) ABP group broilers were fed by a basal diet containing ABPS (500 mg/kg of feed) and saline; (4) CABP group broilers were fed by a basal diet containing ABPS (500 mg/kg of feed) and orally challenged with 10⁸ CFU E. coli K88. Growth performance, serum biochemical indexes, immune responses, intestinal mucosal morphology, and cecal microbial community structure were evaluated. The ABP group had greatest body weight (BW), average daily body weight gain (ADG), and intestinal villus height compared to other treatments (p < 0.05). The CABP group had a higher villus height/crypt depth ratio (V/C) compared with other treatments (p < 0.05). The expression levels of NF-κB were lower in the ABP group. The CNG group had higher Escherichia coli and Enterococcus contents in cecal samples compared to other treatments (p < 0.05). Serum glucose, uric acid, TNF-α, and Secretory Immunoglobulin A (S-IgA) levels were higher in broilers challenged with E. coli (p < 0.001) than that with saline. Broilers challenged with E. coli had reduced taxa richness in the cecal samples. Sequencing of 16S rRNA genes in cecal samples revealed that a lower proportion of Firmicutes and a higher proportion of Proteobacteria were detected in the broilers challenged with E. coli. Compared with the controls, dietary ABPS supplementation increased serum total protein, albumin, and S-IgA levels, but decreased serum glucose, uric acid, and TNF-α levels in broilers (p < 0.05). Diet supplemented with ABPS increased the Firmicutes/Bacteroidetes ratio and the abundance of Ruminococcaceae and Lachnospiraceae, and altered cecal microbiota community structure. These results suggest that ABPS can promote growth performance and improve intestinal morphology and microbiota community structure in broilers challenged with E. coli K88.

Dietary Withania sominefera root confers protective and immunotherapeutic effects against Aeromonas hydrophila infection in Nile tilapia (Oreochromis niloticus)

In the present study, effect of dietary Withania sominefera (W. sominefera) root powder was evaluated to modulate immune and antioxidant response against Aeromonas hydrophila (A. hydrophila) infection in Nile tilapia (Oreochromis niloticus). W. sominefera root powder supplemented diets at two concentrations 2.5% (W 2.5%) and 5% (W 5%); fed for 6 weeks prior to the A. hydrophila challenge and continued the same respective diets during the post challenge period (2 weeks). Results showed that fish fed W. sominefera at 5% enhanced immune response in both pre and post-challenge period. NBT level exhibited only significant increase (P < 0.05) in the pre-challenge period compared to control. Malondialdehyde (MDA) levels in liver and muscle revealed significant decrease in both Withania supplemented groups compared to the control in post challenge period. Antioxidant enzymes activities (catalase/CAT/, glutathione S-transferase/GST/, glutathione/GSH; and superoxide dismutase/SOD) were improved in liver and muscle in post challenge period. Glutathione peroxidase (GPx) level in muscle and serum total antioxidant capacity (TAC) showed a significant increase in both Withania supplemented groups compared to the control post challenge. Withania supplementation enhanced disease resistance against A. hydrophila and reduced mortalities (20%), especially at supplemented concentration of 5%. Our findings suggest that W. sominefera root powder may have protective and immunotherapeutic roles in Nile tilapia against A. hydrophila infection which may be useful in controlling important fish bacterial diseases.

Inclusion of Pediococcus acidilactici as probiotic candidate in diets for beluga (Huso huso) modifies biochemical parameters and improves immune functions

Administration of probiotic candidates in fish has generally been shown as a useful strategy to improve growth performance, survival, digestive enzyme activity, and gut microbiota. Unfortunately, the sero-immunological responses of different fish to different probiotic candidates are poorly understood. The present study assessed the effect of Pediococcus acidilactici as a probiotic on the biochemical and immunological parameters of beluga. Fish (248.32 ± 10.21 g) were fed a control diet (without P. acidilactici( and three different doses of P. acidilactici-supplemented diets (10⁷, 10⁸, and 10⁹ CFUg^-1 diets) for 8 weeks. On week 8, blood and serum were sampled. Dose-dependent increase of immunological parameters (respiratory burst activity, lysozyme content, serum antibacterial activity, and total immunoglobulin) and biochemical parameters (total protein and albumin levels) was observed. However, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were significantly increased in the juvenile beluga fed by 10⁹ CFUg^-1 P. acidilactici-supplemented diet compared to the other groups. Based on the results of this evaluation, it is reasonable to conclude that the inclusion of P. acidilactici as probiotic in diets for juvenile beluga improves the sero-immunological parameters of the fish and should be considered by farmers as a strategy to improve fish health.

Enhancement of broodstock health and maternal immunity in gilthead seabream (Sparus aurata L.) using ExcelMOS®

The current study was conducted to investigate the effect of ExcelMOS® in enhancing the immune system of Sparus aurata broodstock and their impact on offspring health through displaying the maternal transfer of immunity. Broodstock were divided into two groups: one was injected intraperitoneally with ExcelMOS® 1 month before spawning, while the other group was used as a control (without injection). Comprehensive increase in survival rate was observed for larvae hatched from ExcelMOS®-injected broodstock than those of the control (P ≤ 0.05). Hematological analysis showed increases in leukocyte count and hematocrit percentage (P ≤ 0.05) and significant enhancement in immune assays as phagocytic, respiratory burst, lysozyme activities in ExcelMOS®-injected broodstock (P ≤ 0.05). Additionally, total immunoglobulin levels in the serum, eggs, and larvae resulted from ExcelMOS®-injected broodstock were highly significant (P ≤ 0.05) than those in the control ones. Transmission electron microscopy and semi-thin sections in posterior intestine of ExcelMOS®-injected broodstock revealed reinforcement of the epithelial barrier structure, intestinal integrity, and functionality in combination with the stimulation of innate immune system. In conclusion, immunostimulation of Sparus aurata broodstock using ExcelMOS® has improved survival of larvae and enhanced both innate and adaptive immune defense mechanisms. Further investigations are required to show the effect of ExcelMOS® on fish cultured in intensive culture systems.