Aeromonas Hydrophila Research Articles

Effects of Laurus nobilis essential oil nano-particles on growth performance, antioxidant and immune responses to bacterial infection in Nile tilapia, Oreochromis niloticus

This study was designed to assess the effects of four feeds containing 0 (CTL), 25 mg/kg (LN25), 50 mg/kg (LN50) and 100 mg/kg (LN100) Laurus nobilis (LN) essential oil nano-liposomes (LN-NP) on Nile tilapia, Oreochromis niloticus. After 56 days of feeding with the above diets, growth performance and digestive enzyme activities determined in all treatments. Then, the fish were experimentally infected by Aeromonas hydrophila and their survival, antioxidant capacity, biochemical parameters and immune-related transcripts were measured, before and after the infection. The results showed that the growth rate and intestinal activities of amylase, lipase and protease were significantly higher in the LN50 and LN100 treatments than CTL. Post-infection survivals in the LN50 and LN100 treatments were similar and significantly higher than the CTL and LN25 treatments. Compared to the CTL treatment, the LN50 and LN100 treatments showed improved hepatic antioxidant parameters and lower malondialdehyde levels before and/or after infection. Infection significantly decreased plasma lysozyme and complement activities, but the LN50 and LN100 treatments had significantly higher activities before and after infection. These treatments had lower alanine aminotransferase and aspartate aminotransferase activities in plasma before and after infection, compared to the CTL treatment. The expression of tumor necrosis factor-alpha, interleukin-8 and interleukin-1 beta increased significantly in the LN50 and LN100 treatments, before and after infection, when compared to the CTL treatment. Based on the results, LN-NP at a dosage of 50 mg/kg is suitable for feeding Nile tilapia as it is a growth promoter and immunostimulator and increases the resistance of fish to A. hydrophila.

Protective effect of betaine supplementation in low-met diet against Aeromonas hydrophila-induced intestinal injury in grass carp (Ctenopharyngodon idella)

This study evaluated the effect of supplemental betaine in low-methionine (Met) diet concerning the regulatory role of bacteria-induced intestinal injury in fish. 540 grass carp (Ctenopharyngodon Idella) (210 ± 0.68 g) were selected and randomly divided into 6 groups, which contained a reference group fed with the diet supplemented with DL-Met (3.1 g kg−1 diet) and 5 groups fed on the diets added with increasing levels of betaine (0–6.4 g kg−1 diet) for 60 days. Then, a 14-day Aeromonas hydrophila challenge was conducted. Compared with BET0 group, results indicated that appropriate betaine supplementation (1) enhanced antioxidant enzymes activities (except glutathione S-transferase pi-1 (GSTP1) and copper zinc superoxide dismutase (CuZnSOD) and glutathione (GSH) contents, and NF-E2-related-factor 2 (Nrf2) protein nuclear translocation, while reduced reactive oxygen species (ROS), and representative oxidative damage markers; (2) up-regulated the transcription abundance of anti-apoptosis-related molecules while reduced DNA-ladder occurrence and the transcription levels of pro-apoptosis-related genes; (3) down-regulated the transcription of tight junction-related proteins (such as zonula occludens-1 (ZO-1) etc.) in fish intestines. Furthermore, correlation analysis revealed that feeding betaine ameliorating the oxidative damage, apoptosis and tight junction breakdown was possibly related to intestinal Nrf2, p38 mitogen-activated protein kinase (p38 MAPK) and c-Jun N-terminal kinases (JNK), and myosin light chain kinase (MLCK) signaling, respectively. According to the regression analysis for intestinal ROS abundance, claudin-b and caspase-2 transcription, the appropriate betaine supplementations were estimated to be 3.82, 3.98, and 3.62 g kg−1 diet, respectively. Notably, betaine has the potential to spare part Met and the efficacy of betaine relative to Met was 206.67 % based on intestinal ROS contents in grass carp (210–776 g).

Enriched Diet With Orange Essential Oil Citrus sinensis for Tambaqui Colossoma macropomum Promotes Growth Performance and Resistance Against Aeromonas hydrophila.

The objective of this study was to evaluate the effect of dietary supplementation with Citrus sinensis (L.) Osbeck essential oil on the growth, immune system, and resistance to Aeromonas hydrophila infection in Colossoma macropomum fingerlings. The experiment was conducted with five treatments (control diet, Tween80 diet, and diets supplemented with 200, 400, and 800 mg L-1 of C. sinensis essential oil) with four replicates. At the end of the experimental period, growth parameters were measured, and blood samples were collected for thrombogram, leukogram, and phagocytic activity analysis. A bacterial challenge with A. hydrophila was conducted for 96 h. C. macropomum fingerlings that were fed with 400 and 800 mg L-1 of C. sinensis essential oil had the highest growth parameters, with final weights of 533.18 ± 2.03 mg and 531.91 ± 2.67 mg, respectively, and an increase in the number of thrombocytes, lymphocytes, monocytes, and neutrophils, as well as higher phagocytosis rates compared to the control group. Regarding the challenge, fish in the 400 and 800 mg L-1 treatments also exhibited the lowest cumulative mortality rate (26.66% ± 3.33%). Therefore, supplementation with C. sinensis essential oil promotes growth, improves health, and enhances resistance to A. hydrophila in C. macropomum fingerlings.

Stability characterizations of feed-based bivalent vaccine containing inactivated Streptococcus agalactiae and Aeromonas hydrophila against streptococcosis and Aeromonas infections in red hybrid tilapia (Oreochromis sp.).

Feed-based bivalent vaccine (FBBV) containing killed whole organism (KWO) of Streptococcus agalactiae and Aeromonas hydrophila with 10% palm oil was previously proved to improve red hybrid tilapia's (Oreochromis sp.) immunity against streptococcosis and Aeromonas infections. This study characterized the FBBV's stability following the preparatory process and storage. The FBBV was prepared, and the KWO's stability was determined microscopically and molecularly. The efficacy of FBBV stored at room temperature (25 ± 2°C) for 0, 30 and 60 days was investigated in red hybrid tilapia. The results indicated the addition of palm oil was not affecting the KWO's structure and helping in the FBBV's pelletization. In 1g of FBBV contained 1.5 × 109 CFU/g of S. agalactiae and 4.9 × 109 CFU/g of A. hydrophila, respectively, even after 60 days of storage at room temperature. The KWO's structure in FBBV was not affected following in vitro acidic tolerance analysis, as noted from light and electron microscopies. The FBBV's carbohydrate, energy, moisture, total protein and total ash contents remained stable at 95% after 60 days of storage at room temperature, while the KWO's concentration was slightly reduced to 83.3% for S. agalactiae (1.25 × 109 CFU/g) and 80.6% for A. hydrophila (3.85 × 109 CFU/g), respectively. Fish vaccinated with FBBV that was stored for 0, 30 and 60 days did not show any significant differences (p ≥ 0.05) in the relative percent survival when challenged with pathogenic Streptococcus spp. and Aeromonas spp. These findings suggested that the FBBV is a stable vaccine, which underscores its potential application as aquatic vaccines in aquaculture.

Effects of dietary fish meal replacement by Periplaneta americana meal on growth, metabolism, intestinal health and resistance against Aeromonas hydrophila of Micropterus salmoides

An 8-week culture experiment was conducted to investigate the effects of partial replacement of fish meal (FM) with Periplaneta americana meal (PAM) on growth performance, body composition, serum biochemical parameters, intestinal health and resistance against Aeromonas hydrophila of largemouth bass, Micropterus salmoides. A total of 450 healthy largemouth bass with an initial body weight (IBW) of 14.55±0.09 g were randomly divided into five groups. Five experimental diets were prepared by replacing 0 % (P0), 15 % (P15), 30 % (P30), 45 % (P45) and 60 % (P60) of the FM in the basal diet with PAM, respectively. The results showed that final body weight (FBW), weight gain rate (WGR), and specific growth rate (SGR) were no significant difference in P15 and P30 compared with the control group (P > 0.05). Crude protein of whole fish body was significantly increased and crude lipid was significantly decreased in all PAM groups (P < 0.05). In the P30, the antioxidant enzyme activities were significantly higher than those in the control and other experimental groups, and malondialdehyde (MDA) was significantly decreased (P < 0.05). The activities of α-amylase and pepsin increased significantly in P15 and P30 and decreased significantly in P45 and P60 (P < 0.05). Lipase was significantly increased in all groups except P15 than in the control group (P < 0.05). There were no significant differences in villus height (VH), crypt depth (CD), and muscle thickness (MT) among all groups (P > 0.05), but villus width (VW) was significantly decreased in P45 and P60 (P < 0.05). The relative expression of IL-10 and TGF-β1 were first up-regulated and then down-regulated, while IL-8 was opposite (P < 0.05). The relative expression of Casp3, Casp9 and IFN-γ were significantly up-regulated in P45 and P60 (P < 0.05). After injecting A. hydrophila, all groups of largemouth bass experienced mortality, but cumulative mortality was lowest in the P30. In conclusion, PAM can partially replace FM in the diet of juvenile largemouth bass. The replacement of no more than 30 % is unlikely to adversely affect growth performance, and can increase the crude protein content of the whole fish body, and is beneficial to intestinal health.

Effect of Lactobacillus Probiotic Supplement on Growth and Haematological Performance of Indian Major Carp Labeo rohita

The influence of probiotics bacteria Lactobacillus acidophilus improves the survival, growth, and Hematological performance of the Indian major carp Rohu (Labeo rohita). After acclimation, a 60-day experimental study was conducted with four different types of treatments; namely, T1: Control, i.e. Basal feed without Probiotic supplements, T2: Basal feed with Aeromonas hydrophila, T3: Lactobacillus supplemented probiotic feed without Aeromonas hydrophila, and T4: Lactobacillus supplemented probiotic feed with A. hydrophila. After the experimental study, growth parameters were monitored through Weight gain, Specific growth rates, survival percentage, and haematological parameters including WBC, RBC, haemoglobin (Hb), and haematocrit (Hct) values of probiotics treated group (T3 and T4) were significantly (P&lt;0.05) higher than control and T2 group. The Present study indicated that the positive effects of the L. acidophilus probiotic supplement diet improved the survival, growth, and Haematological performance in aquaculture.

Withania coagulans root powder effect on growth, hematology, digestive enzyme activity, antioxidant status, serum immune response, and tolerance against Aeromonas hydrophila in Common Carp

AbstractObjectiveThe use of plant‐derived products in aquaculture has garnered considerable attention due to their potential benefits. This study investigated the impact of supplementing Withania coagulans root powder (WCRP) in the diet of Common Carp Cyprinus carpio on various parameters, including growth performance, digestive enzymes, hematology, antioxidant activity, and immunological aspects.MethodsCommon Carp (mean weight ± standard deviation = 11.69 ± 0.48 g) were divided into four groups in triplicate, receiving different WCRP concentrations (0.0, 1.0, 1.5, and 2.0%; labeled as WCRP0, WCRP1.0, WCRP1.5, and WCRP2.0, respectively) over a 60‐day period, followed by an experimental challenge with Aeromonas hydrophila to assess the relative percentage survival (RPS) over 14 days.ResultResults showed that Common Carp receiving WCRP1.5 and WCRP2.0 demonstrated significantly improved growth performance, with reduced feed conversion ratios (FCRs) being particularly evident in WCRP1.5. Polynomial contrasts indicated significant linear and quadratic effects on weight gain and FCR. Additionally, WCRP1.5 and WCRP2.0 supplementation led to significantly higher activity of digestive enzymes (lipase and protease). Hematological parameters, including white blood cells, red blood cells, hemoglobin, and hematocrit, were significantly elevated in fish that were fed WCRP1.5 and WCRP2.0 compared to the control group. Moreover, serum parameters, such as total protein, albumin, globulin, lysozyme, catalase, superoxide dismutase, and total immunoglobulins, were significantly enhanced in WCRP1.5‐ and WCRP2.0‐treated fish. Notably, the WCRP1.5 group showed the lowest serum cortisol levels. The RPS was highest in WCRP1.5 (73.77%), followed by WCRP2.0 (70.43%), compared to the other groups.ConclusionIn conclusion, supplementation with WCRP1.5 and WCRP2.0 effectively improved both growth and health parameters in Common Carp.

Principal Component Analysis (PCA) of MALDI-TOF for the Identification of Waterborne Pathogenic Bacteria

The study focuses on the application of Principal Component Analysis (PCA) combined with MALDI-TOF MS (Matrix-Assisted Laser Desorption/Ionization-Time of Flight Mass Spectrometry) for the identification of waterborne pathogenic bacteria in urban water networks. In this comprehensive research, 168 bacterial strains were meticulously isolated from the water networks of Abidjan, Côte d'Ivoire, a region known for its inadequate wastewater treatment infrastructure. The analysis aimed to rapidly and precisely identify these bacterial pathogens, leveraging the power of MALDI-TOF MS and the sophisticated data reduction capabilities of PCA. This approach not only accelerates the identification process but also enhances the accuracy of detecting various pathogens. The study identified a diverse range of pathogens, including Pseudomonas aeruginosa, Escherichia coli, Salmonella, Shigella, Vibrio cholerae, Morganella morganii, Proteus mirabilis, Acinetobacter baumannii, Klebsiella pneumoniae, Providencia rettgeri, Providencia stuartii, Aeromonas hydrophila, Bacillus cereus, Lysinibacillus fusiformis, Lysinibacillus sphaericus, and Staphylococcus aureus. These findings underscore the critical public health risks posed by microbial contamination in water networks, particularly in areas with deficient waste management systems. This study highlights the necessity for improved wastewater management practices, robust public health strategies, and regular monitoring to mitigate the risks associated with waterborne pathogens. Moreover, the integration of PCA with MALDI-TOF MS proves to be a powerful tool for enhancing the efficiency and accuracy of pathogen identification in environmental water samples, offering a promising solution for better public health protection and water quality management in urban settings.

Xylanase enhances gut microbiota-derived butyrate to exert immune-protective effects in a histone deacetylase-dependent manner

BackgroundCommensal bacteria in the intestine release enzymes to degrade and ferment dietary components, producing beneficial metabolites. However, the regulatory effects of microbial-derived enzymes on the intestinal microbiota composition and the influence on host health remain elusive. Xylanase can degrade xylan into oligosaccharides, showing wide application in feed industry.ResultsTo validate the immune-protective effects of xylanase, Nile tilapia was used as the model and fed with xylanase. The results showed that dietary xylanase improved the survival rate of Nile tilapia when they were challenged with Aeromonas hydrophila. The transcriptome analysis showed significant enrichment of genes related to interleukin-17d (il-17d) signaling pathway in the xylanase treatment group. High-throughput sequencing revealed that dietary xylanase altered the composition of the intestinal microbiota and directly promoted the proliferation of Allobaculum stercoricanis which could produce butyrate in vitro. Consequently, dietary xylanase supplementation increased the butyrate level in fish gut. Further experiment verified that butyrate supplementation enhanced the expression of il-17d and regenerating islet-derived 3 gamma (reg3g) in the gut. The knockdown experiment of il-17d confirmed that il-17d is necessary for butyrate to protect Nile tilapia from pathogen resistance. Flow cytometry analysis indicated that butyrate increased the abundance of IL-17D+ intestinal epithelial cells in fish. Mechanistically, butyrate functions as an HDAC3 inhibitor, enhancing il-17d expression and playing a crucial role in pathogen resistance.ConclusionDietary xylanase significantly altered the composition of intestinal microbiota and increased the content of butyrate in the intestine. Butyrate activated the transcription of il-17d in intestinal epithelial cells by inhibiting histone deacetylase 3, thereby protecting the Nile tilapia from pathogen infection. This study elucidated how microbial-derived xylanase regulates host immune function, providing a theoretical basis for the development and application of functional enzymes.7BVRPuQYn3eQdwFeU5j8vPVideo

Salinity-responsive hyperaccumulation of flavonoids in Spirodela polyrrhiza, resultant maneuvering in the structure and antimicrobial as well as azo dye decontamination profile of biofabricated zinc oxide nanoentities.

Duckweeds (Spirodela polyrrhiza) are free-floating macrophytes that grow profusely in nutrient-rich waters. Under ideal conditions, they exhibit a rapid growth rate and can absorb a substantial amount of nutrients, macromolecules, and pollutants from bodies of water. Zinc oxide nanoparticles (ZnO NPs) synthesized from plant extracts, particularly under stress conditions, have opened new research avenues in the field of nanotechnology. Under salinity stress, the accumulation of flavonoids in duckweeds can affect the structure of ZnO NPs, helping researchers ascertain their antimicrobial role. In our study, we exposed mid-log phase duckweed monocultures to 75 mM NaCl in a full-strength Murashige and Skoog medium for 7 days, followed by a 15-day recovery period. We observed significant overexpression of superoxide and hydrogen peroxide as reactive oxygen species. As a result, chlorophyll and certain metabolites were produced in lesser amounts, while flavonoid and phenol content increased by 12% and 8%, respectively. This overproduction persisted up to 10 days into the recovery treatment period but dropped by 8% and 5%, respectively, by the 15th day. The flavonoid coating transformed the NPs into rosette clusters, which exhibited reduced antimicrobial activity against Aeromonas hydrophila, a Gram-negative, fish-pathogenic bacterium. Herein, we discuss potential mechanisms for the conformational transformation of ZnO NPs into finer dimensions in response to NaCl-induced oxidative stress in duckweed. In this study, the azo dye degradation capacity of salinity-treated plants increased as the flavonoid profile became enriched. Zinc oxide nanoparticles, both prior to and after salinity treatment, were found to be efficient in scavenging azo dye and mitigating its toxicity, as evidenced by improved germination, growth, and overall plant morphometry.

Protective effect of fructooligosaccharide against oxidative stress and apoptosis induced by Aeromonas hydrophila in Megalobrama amblycephala

This research aimed to investigate the effects of dietary fructooligosaccharides (FOS) on attenuating the Aeromonas hydrophila (A. hydrophila)-induced oxidative stress and apoptosis in blunt snout bream Megalobrama amblycephala. Fish were divided into three groups as follows: C1 (Control), T1 (A. hydrophila), and T2 (A. hydrophila + 4 g/kg FOS). The results showed that the activities of antioxidant enzymes increased, the liver morphology had disorderly arrangement, and extensive cell necrosis occurred because of A. hydrophila-infection. While the dietary FOS improved the above-mentioned liver damage. Additionaly, FOS elevated mRNA levels of pro-apoptotic molecules, including caspase-8 and 9, and down-regulated mRNA levels of the anti-apoptotic molecule Bcl-2, which is triggered by A. hydrophila-infection. The transcriptome analysis showed that the oxidative stress-related DEGs pathways were activated in intestine of blunt snout bream by A. hydrophila-infection. The FOS-added group led to the enrichment of more pathways to health. Further WGCNA co-expression network analysis showed that the screened single genes were clustered into 49 modules. The two modules with the highest association to the five traits (10 hub genes) were chosen to build the network by combining the physiological and biochemical characteristic. In summary, this research offers a foundation for the exploring of A. hydrophila-restoration genes in dietary FOS, and also lays a theoretical foundation for aquaculture in the future.

Metabolite from supernatant of soil and plant-associated bacteria control biofilm of fish pathogens

ObjectivesThis research aimed to identify and quantify the antibiofilm activity of bioactive compounds from bacteria isolated from rhizosphere and nodule butterfly pea (Clitoria ternatea), rhizosphere clove afo 3 (Syzygium aromaticum), nodule mimosa (Mimosa pudica L.), and soil from gold mining land which were recovered from Ternate, Tidore, Obi Island, and Marotai Island, Eastern part of Indonesia.ResultsEight supernatants from soil and plant-associated bacteria were found to have quorum quenching activity against Chromobacterium violaceum. All supernatants exhibited antibiofilm activity against biofilm formed by Aeromonas hydrophila and Vibrio harveyi. The supernatant of FT5 showed the highest activity in disrupting (66.59%) and inhibiting (85.63%) the biofilm of A. hydrophila. For V. harveyi, the supernatant of PTM3 showed the highest disruption activity (72.61%), whileRCA7 showed the highest inhibition activity(75.68%). The Gas Chromatography-Mass Spectrometry (GC-MS) identified fatty acids, ester, and diketopiperazine as the compounds related to the antibiofilm activity. Molecular identification revealed that the isolates belong to the genera Bacillus, Priestia, and Chryseobacterium.

Silver nanoparticles exhibit in vitro anthelmintic and antimicrobial activities against Dactylogyrus minutus (Kulwieć, 1927), and Aeromonas hydrophila in Cyprinus carpio Koi

The study aimed to evaluate the in vitro anthelminthic and antimicrobial activity of silver nanoparticles (AgNPs) against Dactylogyrus minutus and Aeromonas hydrophila, pathogens of Cyprinus carpio Koi. Gill arches of the fish were removed and placed into six-well plates containing 10 mL of tank water with varying concentrations of AgNPs: 100, 400, 500, 600, and 800 mg/L, along with control groups using tank water and distilled water. Each group was tested in triplicate. Parasites were observed every 10 min for 300 min (5 h) using a stereomicroscope, and mortality rates were recorded. Anthelminthic efficacy was calculated at the end of the tests. For the in vitro antimicrobial test, the Minimum Inhibitory Concentration (MIC) of AgNPs was determined by adding 100 μL of Poor Broth (PB) culture medium to all 96 wells of a microplate. The first well was filled with 100 μL of AgNPs, followed by serial dilutions (1:2 ratio). Subsequently, 50 μL of A. hydrophila (1 × 107 CFU/mL) was added to all wells and incubated for 24 h at 28 °C. Results showed that 800 mg/L of AgNPs achieved 87% anthelminthic efficacy within 300 min, while 100 mg/L achieved 47% efficacy. The MIC showed bacterial growth inhibition at 125 mg/mL. Despite the 87% efficacy against parasites within 300 min, AgNPs did not reach 100% efficacy quickly, limiting their potential use in ornamental fish farming. Further studies are needed to assess the toxicity of AgNPs in fish.

Effect of Aeromonas hydrophila infection on leptin receptor overlapping transcript expression in Rana amurensis

The leptin receptor overlapping transcript (LepROT) has been suggested to play several roles in immunomodulatory mechanisms; however, the understanding of its role in Rana amurensis immunity is still very limited. Here, we performed hematoxylin-eosin staining, quantitative reverse-transcription polymerase chain reaction (qRT-PCR), immunofluorescence and western blotting to investigate the roles of LepROT in the immunomodulatory mechanism and the influence of its expression on the nuclear factor-kappa B (NF-κB) signaling pathway, such as the activation of IκB kinase and NF-кB, in amphibian resistance to infection with Aeromonas hydrophila (Ah). After Ah infection, the liver, lung, kidney, skin, muscle, and stomach of R. amurensis showed cell structure disturbance, bleeding, and texture abnormalities. In addition, the relative expression levels of LepROT, NF-кB, IKKα, and IKKβ were all upregulated after Ah infection; however, they showed time-dependent differential expression. The NF-кB signaling pathway exhibited robust expression levels, which might be explained by the positive feedback regulation function of LepROT. Overall, this study provides a basis for further assessment of the biological functions of LepROT and highlights its role in the regulation of immune mechanisms.

The Effects of Dietary Orange Peel Fragments Enriched with Zinc and Vitamins C and E on the Antioxidant and Immune Responses of Nile Tilapia under Stress Conditions.

This study aimed to evaluate the effect of dietary orange peel fragments (OPFs) enriched with vitamins C (C) and E (E), as well as zinc (Zn) on the growth performance, hematological profile, immunological parameters, antioxidant capacity, and fillet lipid peroxidation of Nile tilapia subjected to heat/dissolved oxygen-induced stress (HDOIS), transport-induced stress (TIS), and Aeromonas hydrophila infection (BC). A group of 500 male Nile tilapia (2.7 ± 0.03 g) was randomly distributed in twenty-five 250 L aquaria (20 fish/aquarium) and fed diets containing OPFs (6 g kg-1), OPFs/C (6 g kg-1/1.8 g kg-1), OPFs/E (6 g kg-1/0.4 g kg-1), OPFs/Zn (6 g kg-1/0.21 g kg-1), or OPFs/C/E/Zn (6 g kg-1/1.8 g kg-1/0.4 g kg-1/0.21 g kg-1) for 100 days. The diets were formulated to contain 30% crude protein and 17 MJ kg-1 gross energy. After the feeding period, three groups of fish were independently subjected to a different type of stress: HDOIS (34 °C) for two days; TIS for four hours, or BC for 15 days. The hematological profile, antioxidant capacity, and fillet lipid peroxidation were determined before and after all the stress treatments, along with immunological parameters, which were investigated only for the fish subjected to bacterial infection. In summary, the results showed that growth was not affected by the OPFs, nor by the OPFs enriched with C, E, and Zn; bacterial infection determined anemia for the fish fed any of the experimental diets; the OPFs did not prevent lipid peroxidation under TIS and BC; on the other hand, when enriched with C/E/Zn, lipid peroxidation decreased under HDOIS and TIS. In conclusion, the OPFs enriched with C/E/Zn showed a synergistic effect that promoted an increase in antioxidant enzyme activity, a decrease in lipid peroxidation, and the maintenance of the hematological profile under HDOIS and TIS, but they were not able to maintain the health status under BC.

Comparative analysis of Seabuckthorn and its significant component in enhancing fish mucosal immunity

Seabuckthorn and its significant component, gallic acid, were found to alleviate foodborne enteritis in zebrafish, a model species. To investigate the protective effects on mucosal immunity in cultured fish, seabuckthorn or gallic acid was added to soybean meal feed in a study conducted on juvenile grass carp. After a 5-week feeding trial, histopathology, enteritis-related gene expression, transcriptomics, and 16S rRNA gene sequencing were performed on the hindgut and liver tissues. The results showed that dietary inclusion of seabuckthorn (9.5 g/kg) or gallic acid (1.2 g/kg) prevented enteritis, evidenced by an increase in intestinal villi length and a decrease in goblet cell numbers. The gallic acid group showed benefits in preserving villi length, while seabuckthorn was advantageous in controlling goblet cells. On the molecular level, downregulation of pro-inflammatory genes and upregulation of anti-inflammatory genes were observed. Specifically, seabuckthorn was more effective in controlling cytokine expression, while gallic acid better protected the epithelial barrier function. Omics analysis revealed an upregulated hepatic “PPAR signaling pathway” in the seabuckthorn group and downregulated intestinal “platelet activation” in the gallic acid group, suggesting reduced inflammation and improved immune homeostasis. Regarding intestinal microbiota, both groups showed reduced pathogenic Campilobacterota and Aeromonas, and increased Bacteroides and Cetobacteria, potentially enhancing mucosal immunity. For anti-inflammatory processes, hepatic “fatty acid degradation”, “tryptophan metabolism”, and “FoxO signaling pathway” were elevated only in the seabuckthorn group. Gallic acid was advantaged with more “mitophagy” and “autophagy”. Fish-fed seabuckthorn or gallic acid were challenged with Aeromonas hydrophila to assess impacts on other mucosal surfaces. In the gill, compared to the soybean meal group, significantly higher survival rates, reduced CD4 inflammatory signals, and increased filament space were observed. Comparing seabuckthorn with its active component, seabuckthorn performed better in lipid metabolism, resistance to A. hydrophila, anti-inflammation, and probiotic abundance, while gallic acid mainly showed benefits for mucosal barrier protection, such as increased gill filament space. In summary, seabuckthorn and gallic acid improved mucosal immunity in fish, particularly in the gut and gills, enhancing resistance to bacterial infection and foodborne inflammation. Thus, gallic acid and seabuckthorn may be optimal phytotherapy choices in aquaculture.

Assessment of biocidal efficacy of zinc oxide-zeolite nanocomposites as a novel water disinfectant against commercial disinfectants used in water purification

Water microbial contamination is a serious issue that poses a risk to both animal and human health. One hundred and twenty water were samples collected from main water source and drinkers from a poultry farm. Different bacterial pathogens were isolated from water sources. Escherichia (E.) coli, Pseudomonas (P.) aureoginosa, (Salmonella) Salmonella (s). Typhimurim, Aeromonas (A.) hydrophila at different percentages. Variable degree of bacterial resistance to some commercial disinfectants commonly used to disinfect water system (iodine, terminator and H2O2). Nanoparticles were used to control bacteria in water. About the safety investigation for the prepared nanomaterials, the work results demonstrated that zinc oxide (ZnO) nanoparticles (NPs) exhibit the highest safety profile among the manufactured materials. The median fatal dose (LD50) for ZnO NPs was determined to be 3709 mg/kg body weight. In comparison, the LD50 values for zeolites and nanocomposites were 3251 mg/kg and 2658 mg/kg, respectively. Therapeutic dosages were estimated based on the LD50. Zeolite NPs, ZnO NPs and ZnO/zeolite NPs showing promising results in control of those bacteria. It was concluded that the escalating resistance of bacteria to disinfectants have led to a need to find alternative such as nanoparticles that proved promising results in control of pathogens, particularly it showed a safe effect on laboratory animals.

Two homologous genes encoding interleukin (IL)-34 in the common carp (Cyprinus carpio L.): Roles in inflammatory modulation and anti-bacterial defense

In mammals, interleukin 34 (IL-34) is a ligand for macrophage colony-stimulating factor receptor (M-CSFR), promoting inflammatory responses and inducing the synthesis and secretion of various cytokines. However, studies on its function in lower vertebrates is limited, and its evolutionary relationship with homologous molecules in mammals remains unclear. In this study, two IL-34-encoding genes were cloned and identified in common carp (Cyprinus carpio L.), designated as CcIL-34A and CcIL-34B, with an amino acid sequence similarity of 77.7 %. Gene synteny analysis revealed that the IL-34 gene loci are relatively conserved, and both are located downstream of SF3B3. The expression patterns of CcIL-34s were analyzed using qRT-PCR, and this showed that they are expressed across all tested tissues, with higher levels in the liver, spleen, and head kidney and lower levels in the gills and intestines. Following infection with Aeromonas hydrophila, the mRNA expression levels of CcIL-34s in the gills, head kidney, intestines, and spleen were significantly upregulated. Immunofluorescence was also employed to assess changes in CcIL-34 protein expression, showing a significant increase in carp spleens 24 h after A. hydrophila infection, suggesting that CcIL-34s contribute to host defense against this bacterium. To investigate the immunological function of IL-34 in vivo, pc-CcIL-34A and pc-CcIL-34B eukaryotic expression plasmids were constructed and injected intramuscularly into fish. Five days after injection, the expression levels of inflammation-related cytokines in the head kidney and spleen were significantly altered. Furthermore, 24 h post-A. hydrophila infection, the bacterial loads in the liver, spleen, and kidneys were significantly reduced. Ten days post-infection, the survival rates in the groups with CcIL-34A and CcIL-34B overexpression were 40 % and 36.7 %, respectively, compared to 16.7 % in the control group. These findings suggest that CcIL-34s are involved in modulating inflammatory responses, enhancing the immune response, and improving survival rates in fish following bacterial infection, thus supporting the potential use of IL-34 molecules in aquaculture.

Temperature, dietary lipids, and Aeromonas hydrophila modulate self-protection mechanisms in pacu Piaractus mesopotamicus Holmberg 1887.

Water temperature has a direct influence on several physiological processes in fish. This study investigated the effects of the exposure of pacu (Piaractus mesopotamicus) to 10 days of reduced temperature in stress and innate immune and antioxidant systems, all of which are involved in energy mobilization. Two groups of fish, fed a control diet or a diet with a higher lipid level, were exposed for 10 days to 16°C and then inoculated with Aeromonas hydrophila bacterin. Samples were taken before and after 5 and 10 days of exposure. The results showed that the low temperature (16°C) was a stressor, increasing cortisol levels. Higher levels of cortisol were seen in fish with more body fat, especially at 16°C, compared to those fed control diet. The immune system was enhanced by low temperature that activated the hemolytic activity of the complement system (HAC50) and lysozyme after 10 days of exposure in fish with more body fat. Bacterin inoculation, regardless of temperature and body fat, impaired the respiratory activity of leukocytes, but the complement system activity remained at the levels seen before cold activation. Similarly, lysozyme remained at the levels seen before cold activation, showing later activation. Furthermore, soon after inoculation (at 3 and 6 h), bacterin induced oxidative stress that decreased at 24 h when the concentration of reduced glutathione (GSH) showed lower levels, suggesting that GSH was consumed to attenuate the oxidative stress. Pacu was resilient to the reduced temperature, displaying protective responses to the stressful condition using lipids to modulate these responses.

Ligand modelling of Trachyspermum ammi phytocompounds for Aeromonas hydrophila cell wall synthesis enzyme in Labeo rohita

Aquaculture faces challenges from Aeromonas hydrophila, causing Motile Aeromonas Septicaemia, particularly affecting Labeo rohita (Rohu) in Pakistan. This study explores potential herbal antibacterials targeting A. hydrophila, molecular docking of Trachyspermum ammi (ajwain) phytocompounds against pathogen. The cell wall synthesis ligase, D-alanine–D-alanine ligase (PDB ID 6ll9) was processed in BIOVIA Discovery Studio and docked with 13 antibacterial phytocompounds found after QSAR analysis of T. ammi. Binding energies were calculated using PyRx to assess complex stability. ADME-TOX assessment for selected phytocompounds and parameterisation in CHARMM-GUI were performed. Docking the two best ligands with highest binding energies and ADME-TOX compliance, we found carvacrol and limonene formed most stable protein-ligand complexes, with raw and processed protein. Our findings suggest these herbal compounds can inhibit D-alanine–D-alanine ligase. These in-silico results support the potential of ‘ajwain’ in managing A. hydrophila, further in-vivo experiments are necessary to validate these inhibitory properties.