Serum Lysozyme Research Articles

Black cardamom (Amomum subulatum) extract improves growth potential, antioxidant status, immune parameters and response to crowding stress in Catla catla.

Natural herbs are excellent alternatives to synthetic compounds to enhance the growth performance and health status of fish. This study was conducted to evaluate the efficacy of black cardamom (Amomum subulatum) extract (BCE) as an herbal supplement in improving the growth, antioxidant status, haematology, and serum biochemistry of Catla catla. The acclimatized fish (N = 900; average initial weight = 14.44 ± 0.33 g) were allocated into five groups (60 fish/group in triplicate) in hapas (4 × 2 × 2.5 ft) and provided with feed containing 0 (control), 0.5, 1, 2and 4 g/kg BCE for 90 days before being subjected to 8 days of crowding stress. After 90 days, significantly higher feed utilization and growth were observed in all BCE-fed treatments compared to the control; however, the maximum values of these parameters were noted in the 2 g/kg BCE-fed treatment. Moreover, the BCE-fed groups exhibited a significant increase in antioxidant indices (glutathione peroxidase, superoxide dismutaseand catalase), with a significant reduction in malondialdehyde levels, indicating a higher antioxidant capacity compared to the control. Significant improvements in haematological parameters, such as an increase in haematocrit, haemoglobinand red blood cells and a decrease in white blood cells, were observed in BCE-fed treatments compared to the control. Furthermore, BCE-fed groups showed a significant decrease in serum glucose, cortisoland triglycerides, while total protein, globulinand albumin levels were significantly higher compared with the control. During the feeding trial of 90 days, no mortality was observed; however, the lowest cumulative mortality was noted in the 2 g/kg BCE group after crowding stress of 8 days. In conclusion, the use of BCE in feed can enhance the growth performance, antioxidant status, haematology, and serum biochemistry of C. catla and improve the resistance against crowding stress. The optimum levels of BCE for C. catla were estimated based on weight gain % (1.78 g/kg; R2 = 0.97), feed conversion ratio (1.65 g/kg; R2 = 0.98), MDA content (1.66 g/kg; R2 = 0.93) and serum lysozyme activity (1.72 g/kg; R2 = 1) using broken-line regression analysis.

Dietary fulvic acid increased growth, stress tolerance and disease resistance against Vibrio harveyi in Asian seabass (Lates calcarifer) juvenile

An 8-week husbandry trial was carried out toexamine the impacts of graded levels of dietary fulvic acid (FA) on growth, stress, and disease resistance of Asian seabass (Lates calcarifer, 38.2 g) juveniles. Five levels of FA were included in a basal diet (470 g kg-1 crude protein, 150 g kg-1 crude lipid) to prepare experimental diets, including: 0 (control), 2.5, 5.0, 10, and 15 g kg-1 diet. Two hundred and twenty-five fish (38.2 ± 0.1 g) were stocked randomly into 15 1000-L circular polyethylene tanks (15 fish tank-1) filled with 800 L disinfected seawater and fed with the experimental feeds three times daily. Each dietary treatment had three replicates. Tanks were supplied with seawater (32.2 °C, 45.0 ppt) in a flow-throw system. At the end of the husbandry trial, fish were challenged with Vibrio harveyi and air exposure stress for one min. Fish fed FA-supplemented diets showed a positive quadratic growth response, and those fed with a 5 g FA kg-1 diet had higher final weight and weight gain percentage than the control. Feed intake in fish fed FA-supplemented diets were higher than in control, showing significant linear and quadratic trends (P < 0.05). The highest and lowest skin mucus lysozyme (LYZ) and serum alternative complement pathway (ACH50) activities were in fish fed 10 and 15 g FA kg-1 diets, respectively, exhibiting a quadratic response to dietary FA. Serum total protein level (TP) in fish fed FA-supplemented diets was higher than in the control group. Medium or high levels (10–15 g kg-1) of FA significantly enhanced the survival rate against Vibrio harveyi, which was associated with increased activities of serum lysozyme and ACH50 as well as liver glutathione peroxidase activity in these groups. Air exposure induced oxidative stress in all treatments and gradually reduced antioxidant enzyme activities associated with increased malondialdehyde content in the liver. Furthermore, air exposure suppressed some immune responses, including serum total immunoglobulin and TP levels. Still, LYZ activity was restored after 24 h, with the highest level found in fish fed 5 g FA kg-1 diet. Based on the broken-line regression analysis, the adequate level of FA in the diet for Asian seabass is 4.4 g kg-1.

Haematological and Innate Immunological Reference Intervals for Farmed Yellow Catfish &lt;i&gt;Horabagrus brachysoma&lt;/i&gt; and Their Seasonal Variations

The reference intervals for haematological and innate immune response variables of healthy adult yellow catfish Horabagrus brachysoma raised in captivity were determined. Reference ranges were established for all parameters and significant (P &lt; 0.05) seasonal variations in most of the haematological and innate immune parameters were observed. Total erythrocyte count, packed cell volume, serum lysozyme and myeloperoxidase activities were found to be higher during winter season whereas most of the red blood cell indices, superoxide production by phagocytes, serum ceruloplasmin and anti-protease activities were marked to be significantly higher during rainy season of the year. Except high total leucocyte count and mean corpuscular haemoglobin, other parameters were found to be significantly lower during summer, possibly indicating a higher disease risk in summer months for this species. However, no significant variations in these variables were obtained between male and female catfish during breeding season. The information generated would be indirectly helpful for determining health status of this endangered species.

Preparation, identification, and application of PEG/ZIF-8@ Dendrobium huoshanense polysaccharide as an adjuvant to enhance immune responses

Zeolitic imidazolate framework-8 (ZIF-8) nanoparticles loaded with polysaccharides are excellent drug-delivery carriers with high loading capacity and pH sensitivity. This study describes the one-step encapsulation of Dendrobium huoshanense polysaccharides (DHP) in ZIF-8. The resultant PEG6000/ZIF-8@DHP complex exhibited drug release properties in acidic microenvironments, possessed water solubility, demonstrated high drug loading capacity, and displayed effective encapsulation. The effects of PEG6000/ZIF-8@ DHP administration on immunoregulation, antioxidant activities, and resistance against Aeromonas veronii in channel catfish were assessed. The study revealed that the PEG6000/ZIF-8@DHP complex stimulated cellular proliferation and phagocytosis, while also inducing the production of cytokines and nitric oxide. Additionally, the complex exhibited improved antioxidant properties and increased serum lysozyme and alkaline phosphatase activities. PEG6000/ZIF-8@DHP exhibited efficacy in vivo against Aeromonas veronii infection. These results indicate that PEG6000/ZIF-8@DHP is an efficient immunostimulant and vaccine adjuvant for enhancing immunity in channel catfish.

Immuno-physiological effects of dietary reishi mushroom powder as a source of beta-glucan on Rohu, Labeo rohita challenged with Aeromonas veronii

Beta-glucans have immense potential to stimulate immune modulation in fish by being injected intramuscularly, supplemented with feed or immersion routes of administration. We studied how supplementing Labeo rohita’s diet with reishi mushroom powder containing beta-glucan influenced immunological function. A supplemented diet containing 10% reishi mushroom powder was administered for 120 days. Afterwards, analyses were conducted on different immunological parameters such as antioxidants, respiratory burst, reactive oxygen species (ROS), alternative complement activity, and serum immunoglobulin, which resulted significant increases (p < 0.05; p < 0.01) for the reishi mushroom-fed immune primed L. rohita. Additionally, analyzing various hematological parameters such as erythrocytes and leukocytes count were assessed to elucidate the immunomodulatory effects, indicating positive effects of dietary reishi mushroom powder on overall fish health. Furthermore, the bacterial challenge-test with 1.92 × 104 CFU/ml intramuscular dose of Aeromonas veronii showed enhanced disease-defending system as total serum protein and lysozyme activity levels accelerated significantly (p < 0.01). Nevertheless, reishi mushroom powder contained with beta-glucan ameliorated the stress indicating parameters like acetylcholinesterase (AChE), serum-glutamic pyruvic transaminase (SGPT) and serum-glutamic oxaloacetic transaminase (SGOT) enzyme activities results suggested the fish’s physiology was unaffected. Therefore, the results indicated that adding dietary reishi mushroom as a source of beta-glucan could significantly boost the immune responses in Rohu.

Effects of ribonucleotide supplementation in modulating the growth of probiotic Bacillus subtilis and the synergistic benefits for improving the health performance of Asian seabass (Lates calcarifer).

In aquaculture, due to the requirements for high-density culture, the diseases caused by bacterial pathogens have become a serious issue. To solve this problem, we performed synbiotic application of RNA and Bacillus subtilis as a sustainable and eco-friendly approach to improve the health and immunity of Asian seabass (Lates calcarifer) during cultivation without using any harmful antibiotics or chemicals. Among various forms of nucleic acids, such as mononucleotides and DNA, RNA was found to be most effective in promoting the growth performance of probiotic B. subtilis in all the tested minimal medium conditions. Accordingly, we used the synbiotic combination of B. subtilis and RNA for Asian seabass cultivation. After feed supplementation for fourteen days, the fish that received the combination treatment exhibited a significant increase in innate cellular and humoral immune parameters, including phagocytic activity, phagocytic index, respiratory burst, serum lysozyme and bactericidal activities, as well as upregulated expression of immune-related genes, including HEPC1, A2M, C3, CC, CLEC, LYS, HSP70, and HSP90. Furthermore, significant increases were observed in the ileal villus height and goblet cell numbers in the intestinal villi in all fish treatment groups. The combination treatment did not cause histopathological abnormalities in the intestine and liver, suggesting that the synbiotic treatment is safe for use in fish. The treated Asian seabass also exhibited a significantly increased survival rate after Aeromonas hydrophila challenge. These results indicate that the synbiotic mixture of B. subtilis and RNA can be considered a beneficial feed additive and immunostimulant for Asian seabass cultivation.

Identification of Proteins Adsorbed on Hydroxyapatite Ceramics with a Preferred Orientation to a-Plane

Protein adsorption is essential for determining material biocompatibility and promoting adherent cell growth. In this study, we focused on the a-plane structure of hydroxyapatite (HAp). This a-plane structure closely resembles the crystal plane where apatite is exposed in long bones. We conducted protein adsorption experiments using HAp ceramics with a preferred orientation to a-planes (aHAp), employing bovine serum albumin (BSA), lysozyme, and fetal bovine serum (FBS) as protein models to mimic the in vivo environment. Higher zeta potential and contact angle values were found in aHAp than in HAp ceramics fabricated from commercial HAp powder (iHAp). Bradford-quantified protein adsorption revealed BSA adsorption of 212 ng·mm−2 in aHAp and 28.4 ng mm−2 in iHAp. Furthermore, the Bradford-quantified protein adsorption values for FBS were 2.07 μg mm−2 in aHAp and 1.28 µg mm−2 in iHAp. Two-dimensional electrophoresis (2D-PAGE) showed a higher number of protein-derived major spots in aHAp (37 spots) than in iHAp (12 spots). Mass spectrometry analysis of the resulting 2D-PAGE gels revealed proteins adsorbed on aHAp, including secreted frizzled-related protein 3 and vitamin K epoxide reductase complex 1, which are involved in cellular bone differentiation. Overall, these proteins are expected to promote bone differentiation, representing a characteristic property of aHAp.

Research Note: Effects of feeding corn naturally contaminated with aflatoxin B1, deoxynivalenol, and zearalenone on reproductive performance of broiler breeders and growth performance of their progeny chicks

To evaluate the toxic effects of mycotoxin-contaminated corn (MC) on the breeders and their progeny chicks, a total of 480 fifty-wk-old Cobb broiler breeder hens were fed the following dies: 1) a corn-soybean meal diet (Control; containing 70.35% corn), 2) MC substituting for 50% of corn in Control (LM), 3) LM diet plus 2 g/kg 1 mycotoxin sequestrant, Toxy-Nil Plus (TNP) (LMT2.0), 4) MC substituting for 100% of corn in Control (HM), 5) HM diet plus 2 g/kg TN (HMT2.0), and 6) HM diet plus 2.5 g/kg TNP (HMT2.5). The MC contained 69.25 μg aflatoxin B1 (AFB1)/kg, 4,875 μg deoxynivalenol (DON)/kg, and 2,262 μg zearalenone (ZEN)/kg. At wk 4 after MC inclusion, all eggs laid were used for hatch, and all progeny chicks were fed the same mycotoxin-untreated diet for 14 d. Dietary MC inclusion decreased the hatchability of set eggs and increased embryo mortality during d 18 to 21.5. The TNP addition increased these aforementioned indices in MC-included diets. Maternal HM treatment decreased the BW of progeny chicks at age of 14 d and BWG of progeny chicks during d 1 to 14, whereas maternal LM treatment did not affect these indices. In parallel, maternal HM treatment decreased the concentrations of serum IgA, IgG, and lysozyme in the progeny chicks on d 14, but maternal LM treatment did not affect these indices. Overall, maternal dietary TNP treatments increased the growth of progeny chicks and had a trend to increase the concentrations of serum IgA and IgG on d 14 compared to maternal MC treatments. It was concluded that the feeding of relative high ratio of corn contaminated with low level of AFB1, DON, and ZEN negatively affected the reproductive performance of breeders and the growth performance of their progeny chicks, and TNP addition alleviated these toxic effects.

Hemolysin from Aeromonas hydrophila enhances the host's serum enzyme activity and regulates transcriptional responses in the spleen of Cyprinus rubrofuscus

Aeromonas hydrophila is a conditional pathogen impacting public hygiene and safety. Hemolysin is a virulence factor of Aeromonas hydrophila that causes erythrocyte hemolysis, yet its transcriptional response to Cyprinus rubrofuscus remains unknown. Our investigation confirmed the hemolysis of hemolysin from A. hydrophila. Serum enzyme activity was evaluated weekly after C. rubrofuscus were immunized with hemolysin Ahh1. The results showed that the hemolysin enhances the serum superoxide dismutase (SOD), lysozyme (LZM), and catalase (CAT) activity, which reached a maximum on day 14. To elucidate the molecular interaction between hemolysin from A. hydrophila and the host, we performed transcriptome sequencing on the spleen of C. rubrofuscus 14 days post hemolysin infection. The total number of clean reads was 41.37 Gb, resulting in 79,832 unigenes with an N50 length of 1863 bp. There were 1982 significantly differentially expressed genes (DEGs), including 1083 upregulated genes and 899 downregulated genes. Transcript levels of the genes, such as LA6BL, CD2, and NLRC5, were significantly downregulated, while those of IL11, IL1R2, and IL8 were dramatically upregulated. The DEGs were mainly enriched in the immune disease, viral protein interaction with cytokine and cytokine receptor, and toll-like receptor pathways, suggesting that hemolysin stimulation can activate the transcriptional responses. RT-qPCR experiments results of seven genes, IL-8, STAT2, CTSK, PRF1, CXCL9, TLR5, and SACS, showed that their expression was highly concordant with RNA-seq data. We clarified for the first time the key genes and signaling pathways response to hemolysin from A. hydrophila, which offers strategies for treating and preventing diseases.

Long-term crowding stress induces chronic inflammatory response and declines the immunity of grass carp (Ctenopharyngodon idella)

This study is aimed to explore the mechanism of overcrowding stress on the immunity of grass carp Ctenopharyngodon idella. Fish were reared for 120 days at 10 kg/m3 (low stocking density, LSD), 15 kg/m3 (medium stocking density, MSD) and 20 kg/m3 (high stocking density, HSD). The results showed that HSD significantly increased the serum cortisol level, implying that fish reared at higher density were subjected to physiological stress. HSD led to a remarkable decline in serum lysozyme activity. The conspicuous decrease of serum complement 3 (C3) and immunoglobulin M (IgM) contents also appeared in the HSD group. The serum antioxidant enzymes activity included total antioxidant capacity (T-AOC), total superoxide dismutase (T-SOD), glutathione peroxidase (GPx), and catalase (CAT) of fish reared at HSD group were clearly decreased. The serum glutathione (GSH) concentration of fish reared at HSD group was notably reduced. The malondialdehyde (MDA) level was obviously increased in HSD group. Long-term crowding stress gave rise to the constitution of melano-macrophage centers in spleen. The transcriptional levels of TLR4/NF-κB signaling pathway were notably up-regulated except for iκbα and mTOR pathway related genes were prominently down-regulated in fish reared at HSD group. The notably up-regulated pro-inflammatory cytokines (tnf-α, ifnγ2, il1-β, and il-8) except for il-6 and prominently down-regulated anti-inflammatory cytokines (il-10, il4/13a, il4/13b, tgf-β1 and tgf-β2) appeared in HSD group. All of the above results revealed that long-term overcrowding stress induced unbalanced inflammatory response via TLR4/NF-κB and mTOR signaling pathway and decreased the immunity in grass carp.

Grafting zwitterionic brushes from the surface of an epoxy-based transparent hydrogel for antifouling performance

Non-specific biofilm formation (biofouling) commonly occurs to the surface of biomedical devices, which causes infection to the human tissues and function loss after implantation. To enhance the antifouling properties on the bioinert hydrogel-based biomaterials, a novel surface grafting approach was developed using surface radical chain-transfer reaction mediated by DL-dithiothreitol (DTT), rather than catalyzed by cytotoxic metal ions. Zwitterionic poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) brushes were grafted on the surface of poly(2-hydroxyethyl methacrylate-co-glycidyl methacrylate) (PHG) to obtain PHG-graft-PMPC (PHG-g-PMPC) hydrogel, which were shown to have tunable surface hydrophilicity while maintaining high water content and transparency. Elemental composition analysis and micromorphology demonstrated the success of surface grafting. Protein adhesion assays were carried out, showing the reduction of bovine serum albumin, lactoferrin, and lysozyme adhesion by ∼90%, 80%, and 70%, respectively, compared to the pristine hydrogels. Significant resistance of bacterial attachment was observed on the surface-modified hydrogels using gram-negative Escherichia. coli and gram-positive Staphylococcus aureus, respectively. The PHG-g-PMPC hydrogel is potentially feasible in various biomedical applications, especially for preventing surface biofouling of ophthalmic implants and devices. Furthermore, this de novo approach provides a universal platform for surface functionalization via thiol-epoxy click chemistry and surface radical chain-transfer reaction.

Efficacy of bivalent vaccine against Aeromonas salmonicida and Edwardsiella tarda infections in turbot.

In recent years, more than one pathogenic organism has usually been isolated from diseased turbot Scophthalmus maximus, creating a pressing need for the development of combination vaccines to prevent fish diseases brought on simultaneously by various infections. In this study, the inactivated bivalent vaccine of Aeromonas salmonicida and Edwardsiella tarda was prepared by the formalin inactivation method. After challenge with A. salmonicida and E. tarda at 4 weeks post-vaccination in turbot, the relative percentage survival (RPS) of the inactivated bivalent vaccine was 77.1%. In addition, we assessed the effects of the inactivated bivalent vaccine and evaluated the immunological processes after immunization in a turbot model. Serum antibody titer and lysozyme activity of the vaccinated group were both upregulated and higher than that in control group after vaccination. The expression levels of genes (TLR2, IL-1β, CD4, MHCI, MHCⅡ) that related to antigen recognition, processing and presentation were also studied in the liver, spleen and kidney tissues of vaccinated turbot. All the detected genes in the vaccinated group had a significant upward trend, and most of them reached the maximum value at 3-4 weeks, which had significant differences from the control group, suggesting that antigen recognition, processing and presentation pathway was activated by the inactivated bivalent vaccine. Our study provides a basis for further application of the killed bivalent vaccine against A. salmonicida and E. tarda in turbot, making it good potential that can be applied in aquaculture.

Microencapsulation of Lactobacillus plantarum in the alginate/chitosan improves immunity, disease resistance, and growth of Nile tilapia (Oreochromis niloticus).

This study evaluated the effects of microencapsulation of L. plantarum (as a probiotic) with chitosan/alginate biopolymers (MLCA) on innate immune response, disease resistance, and growth performance of Nile tilapia (Oreochromis niloticus). Four hundred and eighty fish were randomly distributed in glass tanks (150 L) and fed with diets including diet 1: control; diet 2: 10 g kg-1 microcapsules; diet 3: 108 CFU g-1 L. plantarum; and diet 4: 10 g kg-1 MLCA for 60 days. The hematology and biochemical indices, lysozyme activity, alternative complement activities, respiratory burst, serum bactericidal activity, as well as growth performance parameters (specific growth rate, feed conversion ratio) were analyzed. White blood cells, plasma protein and globulin concentration, serum lysozyme, and respiratory burst activities of fish were significantly increased (P < 0.05) in the MLCA diet. A challenge test against Streptococcus agalactiae, at the end of the experiment, showed the highest survival rate of the fish fed with MLCA. Moreover, the fish fed with MLCA showed a significant improvement in SGR (3.12 ± 0.18%) and FCR (1.23 ± 0.20) and had the highest growth performance. These results suggest longer stability of probiotics in the microcapsules, and their immunomodulatory effect can be considered a promising immunostimulant and growth enhancer in the Nile tilapia diet.

Effects of dietary leucine on growth, antioxidant capacity, immune response, and inflammation in juvenile yellow catfish Pelteobagrus fulvidraco.

The experiment was conducted to investigate the effects of dietary leucine on growth, antioxidant capacity, immune response, and inflammation in juvenile yellow catfish. Five diets were formulated to contain five dietary leucine levels: 12.00 (control), 19.00, 26.00, 33.00, and 40.00gkg-1. Each diet was randomly assigned to triplicate groups of 30 juvenile fish (5.02 ± 0.15g) twice daily to apparent satiation for 56days. Weight gain rate, specific growth rate, and activities of liver superoxide dismutase, glutathione peroxidase, and serum lysozyme, as well as immunoglobulin M content, significantly increased with increase in dietary leucine levels up to 26.00gkg-1, but those values decreased significantly with a further increase in dietary leucine. On the contrary, the lowest malondialdehyde content was found in 26.00 and 33.00gkg-1 leucine groups. The expression levels of IGF 1 and MYF 5 genes in muscle were significantly upregulated with increase in dietary leucine levels up to 26.00gkg-1, but the expression of MSTN level showed the opposite trend. The lowest expression levels of IL 8 and TNFɑ genes in the liver were found in 26.00gkg-1 leucine groups. The quadratic regression analysis on weight gain, specific growth rate, and feed conversion ratio against dietary leucine levels indicated that the optimal dietary leucine requirement was estimated to be 26.84-27.00gkg-1of the dry diet.

Efficacy of dietary thiamine supplementation on growth performance, digestive enzymes, immunological responses, and antioxidant capacity of juvenile beluga (Huso huso)

The aim of the current study was to investigate the beneficial effects of dietary thiamine supplementation on physiological, immunological and antioxidant responses in juvenile beluga, Huso huso. The juvenile fish (∼ 3 g) were fed four times a day with diets containing 0 (control), 5 (5 T), 10 (10 T), and 20 (20 T) mg kg−1 thiamine for 12 weeks. Significant increases were observed in growth performance indicators of the fish fed different levels of thiamine, compared to the control group and the best performance was observed in 10 T treatment. The carcass protein content significantly increased in the thiamine-treated fish and the highest protein content was observed in the 10 T treatment. Digestive enzymes’ activities (pepsin, trypsin, lipase, and amylase) significantly increased in the fish fed the thiamine-supplemented diets. The serum alkaline phosphatase, alanine aminotransferase, and aspartate aminotransferase activities significantly decreased in the 10 T and 20 T treatments, compared to the control group. Dietary thiamine supplementation significantly increased the serum lysozyme, alternative complement activities, and IgM level, compared to the control diet and the highest lysozyme activity and IgM level were observed in the 10 T and 20 T treatments. The hepatic superoxide dismutase, glutathione peroxidase, glutathione reductase, glutathione-s-transferase, transketolase activities of 10 T and 20 T treatments were significantly higher than those of the control treatment. The hepatic catalase activities in the thiamine-treated fish were significantly higher than that of the control fish. Contrastingly, the hepatic malondialdehyde contents of the 5 T, 10 T, and 20 T treatments were significantly lower than the control treatment. Although all the dietary thiamine levels (5–20 mg kg−1) showed beneficial effects on different tested parameters, 10 mg kg−1 was the most beneficial level and is recommended for dietary inclusion to improve the growth and health of juvenile beluga.

Effects of copper exposure and recovery in juvenile yellowtail kingfish (Seriola lalandi): Histological, physiological and molecular responses

This study investigated the physiological responses to copper toxicity in liver and gill of juvenile yellowtail kingfish by exposing to 0 (control), 0.0672, 0.12, 0.214, 0.384, 0.672, 1.20, or 2.14 mg/L copper sulfate for 7 days and then recovered for 14 days. The histopathology, enzyme activities and differential gene expression were detected. The results indicate the safe concentration value of copper for juvenile yellowtail kingfish is 0.083 mg/L. Copper exposure caused structural damage to gill and liver, and could be disappeared or restored after the recovery period. Copper exposure enhanced the Cu,Zn superoxide dismutase (Cu/Zn-SOD) and glutathione peroxidase (GSH-Px) activities and the malondialdehyde (MDA) level in liver. However, with increasing copper concentrations, liver aspartate transaminase (AST) and gill Na+/K+-ATPase activities were at first enhanced and then inhibited. Serum lysozyme (LZM) and Cu/Zn-SOD activities were enhanced at low copper concentrations but inhibited at high concentrations, and the activities of alanine transaminase (ALT) and AST significantly increased at greater copper concentrations. After the recovery period, only liver Cu/Zn-SOD activity returned to control level. In contrast, liver GSH-Px activity and MDA levels and gill Na+/K+-ATPase activity, serum LZM and AST activities remained significantly higher than control, but liver AST activity, serum ALT, and Cu/Zn-SOD activities were significantly lower than control. We constructed the gene regulatory networks of molecular pathways in liver and gill in response to copper exposure. The DEGs were enriched mainly in the pathway of lipid metabolism in liver and pathway of oxidative phosphorylation in gill, indicating these respective pathways are involved in the response to copper stress in this species. The present results elucidate some histological, physiological, and molecular mechanisms underlying copper-exposure stresses in yellowtail kingfish, which could help guide the safe utilization of copper sulfate in disease control of farmed individuals.

Sustainable fabrication of zwitterionic nanofiltration membranes with enhanced antifouling performance using sugar

Thin-film composite membranes are vastly utilized to treat wastewater due to their high energy efficiency, low investment and environmental benignity. However, the use of hazardous solvents and non-renewable resources during membrane preparation poses a major threat to human health and the environment. Several tough challenges such as the trade-off effect between permeability and rejection as well as fouling require immediate remediation. To address these issues, this work integrated a green solvent and a bio-monomer, fructose in the membrane substrate and selective layer, respectively. The membrane is fabricated via facile interfacial polymerization with the addition of a zwitterionic monomer, 1-(2-hydroxyethyl) piperazine propane sulfonate (HEPPS) to promote antifouling properties. FTIR and XPS results depicted the formation of a polyesteramide membrane and the incorporation of zwitterion while AFM and FESEM micrographs showed the changes in membrane roughness. The synergistic effect of fructose and HEPPS in the selective layer increased water permeability from 3.54 to 4.77 L m−2 h−1 bar−1 while having a remarkable Na2SO4 rejection of 99.1 %. Additionally, the zwitterionic membrane exhibited superior antifouling properties with a flux recovery ratio of 97.7 % and 93.4 % for bovine serum albumin and lysozyme, respectively. The results suggested that HEPPS and fructose could ameliorate the fouling resistance of the membrane significantly owing to their exceptional hydrophilicity. Moreover, the resultant membrane shows a stable chlorine resistance towards a high concentration of chlorine (10,000 ppm·h). The findings are expected to provide insights in designing membranes with improved antifouling properties and excellent separation performance coupled with green and sustainable fabrication.

Effects of Dietary Fish Meal Replacement with Alternative Protein Ingredients and Their Combinations on Growth Performance, Feed Utilization, Fillet Composition, and Biochemical Parameters of Red Seabream (Pagrus major).

The experiment was conducted to evaluate alternative protein ingredients in a low-fish meal (FM) diet for red seabream (Pagrus major). Twelve experimental diets were formulated. Control diet (CON) was designed to contain 60% FM. Other experimental diets were formulated by replacing 50% of FM from the CON with soy protein concentrate (SPC), corn gluten (CG), meat meal (MM), and/or chicken byproduct meal (CBM). Four diets were designed including one of SPC, CG, MM, or CBM as FM replacer and designated as SPC, CG, MM, and CBM. Six other diets were formulated by adding two ingredients as SPC and CG, SPC and MM, SPC and CBM, CG and MM, CG and CBM, or MM and CBM, and designated as SCG, SMM, SCM, CMM, CCM, and MCM, respectively. The 12th diet (MIX) was formulated by including SPC, CGM, MM, and CBM. Triplicate fish groups (50.2 ± 0.1 g) were hand-fed for 12 weeks. Weight gain (WG) of fish was significantly improved by MM and MCM diets compared to CG, SCG, CMM, and CCM diets. WG of CON, SPC, CM, SMM, SCM, and MIX groups were comparable with MM and MCM groups. The lowest WG was observed in CG and CMM groups. Feed efficiency (FE) was significantly higher in MM group compared to SPC, CG, SGC, and CMC groups. FE of MCM group was significantly higher than CG and SCG groups. Fillet linolenic acid (C18:2n-6) level in CG group was significantly higher than CON, MM, CM, SCM, CCM, and MCM groups. Serum lysozyme activity was significantly higher in MCM and MIX groups. Therefore, a high level of dietary CG reduces the growth performance and feed utilization of red seabream. A mixture of MM and CBM seems to be more efficient in replacing FM from red seabream diet.

Bacterial Co-Infection as a Potential Threat to Farmed Flathead Grey Mullet (Mugil cephalus): Phenotypic and Molecular Diagnosis, Histopathology, Immunity Response, and In Vitro Antibacterial Evaluation

Vibrio alginolyticus, Vibrio chlorea, and Enterococcus cloacae were the main bacterial pathogens investigated during recurrent episodes of mortalities among farmed flathead grey mullet (Mugil cephalus) in the Bahar El-Baqar area, Sharqia governorate, Egypt, during the summer season in 2021. Nevertheless, the contamination of water with heavy metals was evaluated. In this study, a total number of sixty moribund and freshly dead Mugil cephalus were examined clinically and upon post-mortem. Then, the bacterial isolates were subjected to bacteriological phenotypic examination, 16S rRNA gene sequencing, and antibiotic sensitivity testing. Histopathological screening and the immunity response of naturally infected M. cephalus were also implemented. In areas where bacterial strains were recovered in a high percentage, water contamination with Cu, Fe, and Ni was higher than the permissible limit. The results showed a high similarity (99–100%) to Vibrio and E. cloacae strains using phylogenetic analysis of 16S rRNA. Most isolates exhibited sensitivity to florfenicol, ciprofloxacin, and norfloxacin, while they were resistant to erythromycin and amoxicillin. Hemorrhage, oedema, hemosiderosis, and melanomacrophage activation in most affected tissues of infected M. cephalus were detected by light microscopy. Nevertheless, higher levels of AST and ALT, as well as serum inflammatory markers, CRP, and lysozyme activity, were shown in infected fish. There were higher MDA levels, along with a reduction of GSH, SOD, and catalase, in the gills and brain of infected M. cephalus, compared to the control fish. Our obtained data confirmed the high prevalence of Vibrio serovars and E. cloacae in infected grey mullets, describing their histopathological alterations, higher inflammatory response, and oxidative stress impact. These results could be useful indicators for understanding the pathogenesis of these pathogens in correlation with water parameter deterioration. Thus, the emergence of Vibrio and E. cloacae species in this study threatens the brackish water aquaculture industry in Egypt and poses a public health concern.

Effects of dietary replacement of fishmeal by cottonseed meal on the growth performance, immune and antioxidant responses, and muscle quality of juvenile crayfish Procambarus clarkii

The current research was aimed to determine the impacts of cottonseed meal substitution levels for fishmeal on the growth performance, immune indices, antioxidant ability, and muscle texture of red swamp crayfish (Procambarus clarkii). Five isonitrogenous and isolipidic diets were formulated to feed the crayfish for 8 weeks. The basal diet contained 20% fishmeal (FM), while the other four experimental diets substituted fishmeal in FM diet with cottonseed meal at levels of 25%, 50%, 75%, and 100%, referred to as CM25, CM50, CM75, and CM100 respectively. A total of 750 crayfish with an average initial weight of 4.00 g were selected and randomly allocated to fifteen cages. Each diet was randomly assigned to triplicate groups of crayfish. Weight gain and specific growth rate declined, and feed conversion rate, asparate aminotransferase and alanine transaminase activities appear to increase as cottonseed meal substitution levels increased. Serum total cholesterol levels declined in crayfish fed CM100 diet compared to crayfish fed the FM diet. Serum phenoloxidase and lysozyme activities, and muscle hardness and mef-2a mRNA expression were the highest for crayfish fed fishmeal-based diet and showed no significant difference among other four groups. Dietary cottonseed meal levels did not significantly influence hepatopancreas index, viscerosomatic index, condition factor, serum glucose, triglyceride, albumin, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol and creatinine contents, as well as the contents of acid phosphatase, and alkaline phosphatase, and muscle texture profile (cohesiveness, springiness, adhesiveness, and chewiness) and mef-2b and mstn mRNA expression. High dietary fish meal replacement by cottonseed meal tended to upregulate mRNA expression of nuclear factor erythroid 2-related factor 2, glutathione peroxidase, glutathione reductase, manganese superoxide dismutase, glutathione S-transferase, and catalase. Taken together, dietary cottonseed meal reduced growth performance and feed utilization, induced hepatopancreas oxidative stress, and influenced some serum and muscle parameters. The gossypol content and unbalanced amino acid profile are considered the limiting factor influencing the fish meal replacement by cottonseed meal.