Dietary supplementation of drumstick tree, Moringa oleifera, improves mucosal immune response in skin and gills of seabream, Sparus aurata, and attenuates the effect of hydrogen peroxide exposure

Fishmeal substitution by zooplankton or Daphnia magna biomass meals in the diet of Nile tilapia: Effects on growth, gut histological changes, bacterial abundance and stress tolerance

Fishmeal substitution with sustainable feed sources is highly essential towards sustainable production. This study aimed to investigate the effects of substituting fishmeal (FM) with Daphnia magna biomass meal (DBM) or zooplankton biomass meal (ZBM) on growth performance, liver and intestinal histology, gut bacterial abundance and stress tolerance of Nile tilapia, Oreochromis niloticus, fry. Nile tilapia fry (0.23 ± 0.04 g) were randomly assigned to five groups of three replicates. The control diet comprised 300 g/kg FM, and the FM was substituted with DBM or ZBM at levels of 25% and 50% (DBM-25, DBM-50, ZBM-25 and ZBM-50 respectively) in the other experimental diets. The experiment lasted 56 days in 1.5 m3 concrete tanks. The results revealed that weight gain and feed conversion ratio (FCR) significantly (p ≤ 0.035 and 0.025 respectively) improved with a polynomial response with a peak at 25% ZBM and a linear increase with DBM up to 50% of FM. Histometric indices of the distal intestine showed improvements (p ≤ 0.001) in villus height, villus width, crypt depth and muscle thickness of fish fed DBM or ZBM compared to the control. In the meantime, there were no histological abnormalities in the liver sections. The replacement of FM with DBM or ZBM could modulated gut bacterial abundance, including total bacterial count, Escherichia coli, Bacillus subtilis, and Lactobacillus sp. The fish-fed DBM or ZBM-containing diets had higher (p ≤ 0.05) tolerances to salinity stress than the control group. In conclusion, DBM or ZBM could replace FM up to 50% and 25%, respectively with improved fish growth performance, FCR, gut histology and tolerance to salinity stress.

Immunomodulatory, antioxidant, and growth-promoting activities of dietary fermented Moringa oleifera in Nile tilapia (Oreochromus niloticus) with in-vivo protection against Aeromonas hydrophila

BACKGROUND

Moringa oleifera, a well-known medicinal plant, has been used in aquafeed as a dietary supplement. Based on previous studies, insufficient research is available on the dietary supplementation of Nile tilapia with M. oleifera leaf and seed mixtures, specifically the fermented form. Therefore, this study aimed to investigate the efficacy of fermented (FMO) versus non-fermented M. oleifera (MO) leaf and seed mixtures on immunological parameters, antioxidant activity, growth performance, and resistance to A. hydrophila infection after a 30-day feeding trial on Nile tilapia.

METHODS

A total of 180 fingerlings were randomly divided into four groups in addition to the control group (36 fish each, in triplicate). Fish in the tested groups were fed on basal diet supplemented with MO5%, MO10%, FMO5%, and FMO10%, while those in control were fed on basal diet only. After the feeding trial, fish were challenged with A. hydrophila. The immunomodulatory activity of M. oleifera was evaluated in terms of phagocytic and lysozyme activities, immune-related cytokines and IgM gene expression. Antioxidants, and growth-promoting activities were also assessed.

RESULTS

The results revealed that fish supplemented FMO markedly in FMO10% group followed by FMO5%, exhibited significant (P < 0.05) improvement in the tested immunological, hepatic antioxidants, and growth performance parameters. Furthermore, the highest survival rate post-challenge with mild clinical symptoms, and the lowest A. hydrophila bacterial count were reported in these groups. Meanwhile, MO10%-supplementation exhibited the opposite trend.

CONCLUSIONS

The study' conclusion suggests that fermented M. oleifera leaf and seed mixture is a promising growth-promoting and immunostimulatory feed-additive candidate for Nile tilapia and could reduce the losses caused by A. hydrophila infection.

Disturbance of oxidation/antioxidant status and histopathological damage in tsinling lenok trout under acute thermal stress

The tsinling lenok trout (Brachymystax Lenok tsinlingensis) is a typical land-locked cold salmon. In this study, through the acute high temperature stress (16, 24, and 26°C), samples were taken at multiple temperature points to analyze the dynamic changes of serum non-specific immune indexes and histopathological changes of tissues of tsinling lenok trout. The histopathological investigation of different studied tissues revealed an increase of histological lesions' frequency and severity with increasing water temperature. The activity of T-SOD, GSH-Px, CAT, ACP, and LZM and MDA concentration are all impacted by high temperature stress. The activities of T-SOD, GSH-Px, and ACP are significantly lower in temperatures higher than 16°C (P<0.05). However, with the increase of water temperature, MDA content increased significantly. The activities of CAT and LZM were the highest at 24°C, which were significantly higher than those at 26°C (P<0.05). The above results indicate that 24°C is a "critical high temperature point" for tsinling lenok trout under heat stress, and this temperature point may be the critical point for tsinling lenok trout to enter "damaged" from adaptive adjustment. Our results can provide a theoretical basis for the development of genetic breeding, improvement, and control measures of heat stress in tsinling lenok trout in the future.

Functional Additives in a Selected European Sea Bass (Dicentrarchus labrax) Genotype: Effects on the Stress Response and Gill Antioxidant Response to Hydrogen Peroxide (H2O2) Treatment

Functional ingredients have profiled as suitable candidates for reinforcing the fish antioxidant response and stress tolerance. In addition, selective breeding strategies have also demonstrated a correlation between fish growth performance and susceptibility to stressful culture conditions as a key component in species domestication processes. The aim of the present study is to evaluate the ability of a selected high-growth genotype of 300 days post-hatch European sea bass (Dicentrarchus labrax) juveniles to use different functional additives as endogenous antioxidant capacity and stress resistance boosters when supplemented in low fish meal (FM) and fish oil (FO) diets. Three isoenergetic and isonitrogenous diets (10% FM/6% FO) were supplemented with 200 ppm of a blend of garlic and Labiatae plant oils (PHYTO0.02), 1000 ppm of a mixture of citrus flavonoids and Asteraceae and Labiatae plant essential oils (PHYTO0.1) or 5000 ppm of galactomannan-oligosaccharides (GMOS0.5). A reference diet was void of supplementation. The fish were fed the experimental diets for 72 days and subjected to a H₂O₂ exposure oxidative stress challenge. The fish stress response was evaluated through measuring the circulating plasma cortisol levels and the fish gill antioxidant response by the relative gene expression analysis of nfΚβ2, il-1b, hif-1a, nd5, cyb, cox, sod, cat, gpx, tnf-1α and caspase 9. After the oxidative stress challenge, the genotype origin determined the capacity of the recovery of basal cortisol levels after an acute stress response, presenting GS fish with a better pattern of recovery. All functional diets induced a significant upregulation of cat gill gene expression levels compared to fish fed the control diet, regardless of the fish genotype. Altogether, suggesting an increased capacity of the growth selected European sea bass genotype to cope with the potential negative side-effects associated to an H₂O₂ bath exposure.

Exposure to oxyfluorfen-induced hematobiochemical alterations, oxidative stress, genotoxicity, and disruption of sex hormones in male African catfish and the potential to confront by Chlorella vulgaris

The present study evaluated the effect of chronic exposure to oxyfluorfen (OXY) on different physiological responses of male African catfish, Clarias gariepinus, and the ameliorative effect of Chlorella vulgaris. The fish (160 ± 5.10 g) were exposed to 1/20 LC₅₀ of OXY (0.58 mg/L) for 60 consecutive days with or without co-administration of C. vulgaris (25 g/kg diet) in triplicate groups. The results revealed that chronic exposure to a sublethal level of OXY induced severe anemia and leukopenia. OXY-exposed fish experienced hypoproteinemia, marked lower AchE levels, and a significant increase in glucose, liver, and kidney function biomarkers. The DNA fragmentation of the liver increased by 15 % in fish compared to the control. On the other hand, lipid peroxidation, superoxide dismutase, and catalase activities were markedly increased in the liver and testes homogenates of the OXY-exposed fish. Meanwhile, total antioxidant capacity and glutathione S-transferase levels declined in the same tissues. Exposure to OXY induced a significant reduction in testosterone and luteinizing hormone levels and a significant increase in follicle stimulating hormone and estradiol. Meanwhile, C. vulgaris dietary supplementation succeeded in alleviating the negative impact of OXY on hematobiochemical parameters and restoring the antioxidant balance in the liver and testes. Furthermore, it ameliorated endocrine disruption and repaired sex hormone levels. In conclusion, exposure to OXY could induce systemic stress, oxidative stress, and endocrine disruption in male C. gariepinus. The dietary supplementation of C. vulgaris could be a potential protective strategy against the toxicity of OXY.

Effects of Dietary Vegetable Oil Mixtures including Soybean Oil on Intestinal Oxidative Stress in Gilthead Sea Bream (Sparus aurata)

Fish oil is commonly replaced by vegetable oils in sea bream diets, but little is known about their effects on intestinal health regarding oxidative stress biomarkers. The negative effects of lipid peroxidation on digestive mucosa could have consequences in animal nutrition and welfare. In this study, five isonitrogenous (46%) and isolipidic (22%) diets with 75% of vegetable oils inclusion were evaluated: soybean oil (S) alone or different mixtures containing soybean oil with linseed (SL), linseed and rapeseed (SLR), linseed and palm (SLP), and linseed, rapeseed, and palm (SLRP). Gilthead sea bream juveniles were fed twice a day for 18 weeks. Pyloric caeca and proximal intestine samples were collected 24 h post feeding for lipid peroxidation (LPO), antioxidant enzyme activities (SOD, CAT, GPx, GST, and GR) and gene expression analyses. Pyloric caeca presented larger unhealthy changes in oxidative status than proximal intestine. Although SL-fed fish showed the highest antioxidant activities, they were unable to cope with LPO that in pyloric caeca was 31.4 times higher than in the other groups. Instead, SLP fish presented the best oxidative status, with low LPO levels, antioxidant enzyme activities, and gene expression. In summary, between the vegetable oils dietary mixtures tested, SPL would maintain better intestinal health.

Parasitological, Molecular, and Histopathological Investigation of the Potential Activity of Propolis and Wheat Germ Oil against Acute Toxoplasmosis in Mice

Toxoplasmosis is one of the most common parasitic zoonoses that affects all vertebrates. The drugs most commonly used against toxoplasmosis have many side effects, making the development of new antiparasitic drugs a big challenge. The present study evaluated the therapeutic effectiveness of novel herbal treatments, including propolis and wheat germ oil (WGO), against acute toxoplasmosis. A total of 50 albino mice were divided into five groups: group 1 (G1) (non-infected and non-treated); group 2 (G2) (infected without treatment); group 3 (G3) (treated with propolis); group 4 (G4) (treated with WGO); group 5 (G5) (treated with a combination of propolis and WGO). The effects of the herbal substances on different organs, mainly liver, spleen, and lungs, were investigated using parasitological, molecular, and histopathological examinations. The results of parasitological examination demonstrated statistically significant (p < 0.05) differences in the parasitic load between treated groups (G3, G4, and G5) compared to the control positive group (G2). These differences were represented by a significant reduction in the parasite load in stained tissue smears from the liver obtained from the animals treated with propolis (G3) compared to the parasite load in the positive control group. Similarly, animals (G4) treated with WGO exhibited a significant reduction in the parasite load versus the positive control group, while the lowest parasite load was found in G5, treated with propolis and WGO. Quantification of the parasite burden through molecular methods (PCR) revealed similar findings represented by reduction in the parasite burden in all treated groups with WGO and propolis as compared to the control group. Importantly, these previous parasitological and molecular findings were accompanied by a marked improvement in the histopathological picture of the liver, spleen, and lungs. In conclusion, propolis and WGO showed a good combination of therapeutic efficacy against acute toxoplasmosis.

Dietary supplementation with Moringa oleifera leaves extract reduces the impacts of sub-lethal fipronil in Nile tilapia, Oreochromis niloticus

This study assessed the restorative dietary effects of Moringa oleifera (MO) leaves extract against the negative impacts of sub-lethal fipronil (FIP) toxicity in Nile tilapia. To achieve this purpose, the growth, body composition, haemato-biochemical measurements, serum immunity, and antioxidant condition of Nile tilapia have been examined. Fish were arranged into 6 experimental groups in quadruplicates. Three groups were fed on diets supplemented with 0.0 (reference group), 1.0 (MO1), and 2.0 (MO2) g kg^-1 of MO leaf extract. The other three groups were fed on the same MO levels and concomitantly subjected to a sub-lethal FIP concentration (4.2 µg L^-1 for 3 h only per day) and defined as FIP, FIP + MO1, and FIP + MO2. The experiment lasted for 8 weeks. Results unveiled that growth parameters were significantly decreased alongside an increased feed conversion ratio in the FIP-intoxicated group. The moisture and crude protein (%) were decreased significantly together with a significant increase of the crude lipids (%) in the fish body of the FIP group. Sub-lethal FIP toxicity induced hypochromic anemia, leukopenia, hypoproteinemia, hypoalbuminemia, hypoglobulinemia, and hepato-renal failure (increased urea and creatinine concentrations, as well as ALT and AST enzymes). Exposure to sub-lethal FIP also induced (a) immunosuppression manifested by a decline in total IgM, complement C3, and lysozyme activities, (b) enzymatic antioxidant misbalance manifested by decreases in SOD and CAT activities, and (c) oxidative stress (declined T-AOC and elevated of MDA concentrations). On the other side, dietary supplementation with MO leaf extract in FIP + MO1 and FIP + MO2 groups noticeably modulated the aforementioned parameters. Therefore, we can conclude that dietary MO could reduce sub-lethal FIP toxicity in Nile tilapia with a possible recommendation for regular prophylaxis supplementation in Nile tilapia diets.

Ameliorative Effect of Quercetin against Abamectin-Induced Hemato-Biochemical Alterations and Hepatorenal Oxidative Damage in Nile Tilapia, Oreochromis niloticus

Abamectin (ABM) is a common agricultural pesticide and veterinary anthelmintic drug. It can discharge from the sites of application to aquatic systems via surface run-off or spray drift, causing harmful effects to aquatic organisms. The present study investigated the protective effect of dietary quercetin supplementation on hemato-biochemical parameters and hepato-renal oxidative stress biomarkers in Nile tilapia (Oreochromis niloticus) exposed to a sublethal dose of ABM. Fish were allocated into six equal groups. The first group was kept as a control group. The second and third groups (Q₄₀₀, and Q₈₀₀) were fed diets supplemented with two quercetin levels (400 and 800 mg/kg diet), respectively. The fourth group (ABM) was intoxicated with 20.73 µg/L of ABM. The fifth and sixth groups (ABM + Q₄₀₀, and ABM + Q₈₀₀) were fed diet supplemented with two quercetin levels (400 and 800 mg/kg diet) and simultaneously intoxicated with ABM for 60 days. The results showed that ABM significantly decreased RBCs, hemoglobin content, hematocrit, total protein, albumin levels, and acetylcholinesterase activity activities compared to the control. Meanwhile, ABM significantly increased white blood cells, glucose, total lipids, cholesterol, and alanine and aspartate aminotransferase activities. Liver and kidney levels of lipid peroxidation was significantly increased, while hepato-renal antioxidant biomarkers (reduced glutathione, super oxide dismutase, catalase, and total antioxidant capacity) were significantly decreased upon ABM exposure. On the other hand, quercetin dietary supplementation improved the hemato-biochemical alterations and alleviated oxidative stress induced by ABM exposure. Fish supplemented with quercetin at a level of 800 mg/kg diet showed better alleviating effects against ABM compared to 400 mg/kg diet. Based on these study findings, we suggest that quercetin dietary supplementation (800 mg/kg) offered direct protection against ABM-induced physiological disturbance and oxidative stress in Nile tilapia.

Moringa oleifera alleviated oxidative stress, physiological and molecular disruption induced by acute thermal stress in grass carp, Ctenopharyngodon idella

The present study was designed to investigate the protective effect of dietary Moringa oleifera leaf meal (MLM) supplementation against high temperature-induced stress in grass carp (Ctenopharyngodon idella). A total of 180 apparent healthy juvenile grass carp (15.48 g ± 0.054) were divided into three groups in triplicate (20 fish in each replicate). Fish were fed with diets containing 0, 1, and 5% MLM for 60 days and then subjected to a high-temperature challenge for 48 h (32-33 °C). The results revealed that feeding fish with 1 and 5% MLM resulted in a significant increase in weight gain and specific growth rate compared to the control. In addition, feed conversion ratio was significantly reduced in groups fed with MLM. No significant difference was reported in the serum cortisol level among different experimental groups before heat stress while serum glucose level significantly decreased in fish fed with 5% MLM. Serum alanine transaminase, aspartate transaminase, and alkaline phosphatase significantly decreased in fish fed with 1 and 5% MLM before and after heat stress. Hepatic lipid peroxidation significantly decreased in fish fed with MLM for 60 days. A non-significant increase in hepatic reduced glutathione level was reported in fish fed with 1 and 5% MLM before heat stress. Catalase and superoxide dismutase activities increased significantly in the liver of fish fed with 5% MLM. No significant change was observed in the expression profile of heat shock protein (hsp) 70 and 90 before heat stress. Meanwhile, after heat stress, up to a fivefold increase was recorded in mRNA level of hsp 70 and fourfold increase in the expression level of hsp 90 in the liver of the control fish which were not fed with MLM-supplemented diets. Fish fed with 1 and 5% MLM showed a significant decrease in the expression of hsp 70 and a non-significant decrease in the expression of hsp 90. Results of the present study suggest that supplementing the diet of grass carp with 5% MLM could improve growth and physiological performance and provide resistance against high temperature-induced stress.

Gill Oxidative Stress Protection through the Use of Phytogenics and Galactomannan Oligosaccharides as Functional Additives in Practical Diets for European Sea Bass (Dicentrarchus labrax) Juveniles

The aim of the present study is to evaluate the potential of two functional additives as gill endogenous antioxidant capacity boosters in European sea-bass juveniles fed low-FM/FO diets when challenged against physical and biological stressors. For that purpose, two isoenergetic and isonitrogenous diets with low FM (10%) and FO (6%) contents were supplemented with 5000 ppm plant-derived galactomannan-oligosaccharides (GMOS) or 200 ppm of a mixture of garlic and labiate plant essential oils (PHYTO). A control diet was void from supplementation. Fish were fed the experimental diet for nine weeks and subjected to a confinement stress challenge (C challenge) or a confinement stress challenge combined with an exposure to the pathogen Vibrio anguillarum (CI challenge). Both GMOS and PHYTO diets attenuated fish stress response, inducing lower circulating plasma cortisol and down-regulating nfκβ2 and gr relative gene-expression levels in the gill. This attenuated stress response was associated with a minor energetic metabolism response in relation to the down-regulation of nd5 and coxi gene expression.

Improving survival, growth, feed utilization, antioxidant status, and fatty acids profile of European seabass, Dicentrarchus labrax, larvae fed silymarin, Silybum marianum, supplemented weaning diet

To sustain normal development, high survival, and rapid growth, marine fish larvae require a diet rich in polyunsaturated fatty acids, which could decrease the risk of reactive oxygen species accumulations. Consequently, a 60-day feeding experiment was conducted to determine the effect of silymarin (SM) supplementation in weaning diets on the growth performance, survival, antioxidant enzyme activities, and fatty acids profile of European seabass (Dicentrarchus labrax) larvae. Four isonitrogenous and isolipidic diets were investigated using SM at levels of 0, 200, 400, and 600 mg kg−1 (SM0.00, SM200, SM400, and SM600, respectively). The findings showed that, in a dose-dependent manner, increasing dietary levels of SM enhanced survival, growth, and feed utilization. In the SM600 group, the weight gain, survival, and feed conversion ratio (FCR) improved by 123.21, 11.66, and 38.72%, respectively, compared to the control group. The dose-response analysis demonstrated a strong positive correlation (R2=0.96) between SM levels and weight increase, and a strong negative correlation (R2=0.88) between SM levels and FCR. The antioxidant enzyme activities of larvae given SM-enriched diets were significantly greater than those of the control group. Compared to the control group, the CAT and SOD improved by 81.77 and 5.08 % in the SM600 group. In addition, the saturated fatty acid content reduced while the unsaturated fatty acid content increased, particularly in the SM600 group. The results indicate that supplementing the micro diet of European seabass larvae during weaning with SM at a dose of 600 mg kg-1 increases growth, survival, antioxidant status, and fatty acid profiles.

Physiological Performance, Antioxidant and Immune Status, Columnaris Resistance, and Growth of Nile Tilapia That Received Alchemilla vulgaris-Supplemented Diets

The current perspective is a pioneering trial to assess the efficacy of the dietary supplementation of Alchemilla vulgaris powder (AVP) in the diet of Nile tilapia (Oreochromis niloticus) on growth performance, blood picture, hepatic and renal biomarkers, immune status, and serum and tissue antioxidant capacity and to investigate the resistance against Flavobacterium columnare challenge. Fish (n = 360) were distributed into six groups (three replicates each) and received increasing AVP supplementation levels (0, 2, 4, 6, 8, and 10 g kg⁻¹) for 60 days. Furthermore, fish were exposed to the bacterial challenge of a virulent F. columnare strain and maintained under observation for 12 days. During the observation period, clinical signs and the cumulative mortality percentage were recorded. The results demonstrated that the growth performance, feed conversion ratio, and hematological profile were noticeably enhanced in the AVP-supplemented groups compared to the control. The most promising results of weight gain and feed conversion ratio were recorded in the groups with 6, 8, and 10 g AVP kg⁻¹ diets in a linear regression trend. The levels of hepatorenal function indicators were maintained in a healthy range in the different dietary AVP-supplemented groups. In a dose-dependent manner, fish fed AVP dietary supplements displayed significant augmented serum levels of innate immune indicators (lysozyme, nitric oxide, and complement 3) and antioxidant biomarkers (Catalase (CAT), superoxide dismutase (SOD), total antioxidant (TAC), and reduced glutathione (GSH) with a marked decrease in myeloperoxidase (MPO) and malondialdehyde (MDA) levels). Likewise, hepatic CAT and SOD activities were significantly improved, and the opposite trend was recorded with hepatic MDA. The highest AVP-supplemented dose (10 g/kg) recorded the highest immune-antioxidant status. Based on the study findings, we highlight the efficacy of AVP as a nutraceutical dietary supplementation for aquaculture to enhance growth, physiological performance, and immune-antioxidant status and as a natural economic antibacterial agent in O. niloticus for sustaining aquaculture. It could be concluded that the dietary supplementation of 10 g AVP/kg enhanced O. niloticus growth, physiological performance, immune-antioxidant status, and resistance against F. columnare.

Growth Performance, Immune-Related and Antioxidant Genes Expression, and Gut Bacterial Abundance of Pacific White Leg Shrimp, Litopenaeus vannamei, Dietary Supplemented With Natural Astaxanthin

The current study examines the effect of dietary supplementation of ethanolic extract of Arthrospira platensis NIOF17/003, which is mainly natural astaxanthins (97.50%), on the growth performance, feed utilization, bacterial abundance, and immune-related and antioxidant gene expressions of the Pacific white leg shrimp, Litopenaeus vannamei. A total of 360 healthy L. vannamei postlarvae (0.19 ± 0.003 g) were divided into four groups (0, 2, 4, and 6 g natural astaxanthins/kg diet) each in three replicates, at an initial density of 30 PLs per tank (40 L capacity). The shrimp were fed the tested diets three times a day at a rate of 10% of their total body weight for 90 days. Diets supplemented with different astaxanthin levels significantly improved shrimp growth performance and feed conversion ratio compared to the control diet. No significant differences were observed in survival rates among all experimental groups. The immune-related genes (prophenoloxidase, lysozyme, beta-glucan binding protein, transglutaminase, and crustin) mRNA levels were significantly upregulated in groups fed with different concentrations of the natural astaxanthins in a dose-dependent manner. The prophenoloxidase gene is the highest immune-upregulated gene (14.71-fold change) in response to astaxanthin supplementation. The superoxide dismutase mRNA level was significantly increased with increasing dietary astaxanthin supplementation. In addition, increasing astaxanthin supplementation levels significantly reduced the count of heterotrophic bacteria and Vibrio spp. in the culture water and shrimp intestine. Overall, the current results concluded that diet supplementation with natural astaxanthin, extracted from Arthrospira platensis, enhanced the growth performance, immune response, and antioxidant status of L. vannamei.

Purification and Characterization of Gum-Derived Polysaccharides of Moringa oleifera and Azadirachta indica and Their Applications as Plant Stimulants and Bio-Pesticidal Agents

Plant gums are bio-organic substances that are derived from the barks of trees. They are biodegradable and non-adverse complex polysaccharides that have been gaining usage in recent years due to a number of advantages they contribute to various applications. In this study, gum was collected from Moringa oleifera and Azadirachta indica trees, then dried and powdered. Characterizations of gum polysaccharides were performed using TLC, GC-MS, NMR, etc., and sugar molecules such as glucose and xylose were found to be present. Effects of the gums on Abelmoschus esculentus growth were observed through root growth, shoot growth, and biomass content. The exposure of the seeds to the plant gums led to bio stimulation in the growth of the plants. Poor quality soil was exposed to the gum polysaccharide, where the polysaccharide was found to improve soil quality, which was observed through soil analysis and SEM analysis of soil porosity and structure. Furthermore, the plant gums were also found to have bio-pesticidal activity against mealybugs, which showed certain interstitial damage evident through histopathological analysis.

Sanguinarine attenuates hydrogen peroxide-induced toxicity in liver of Monopterus albus: Role of oxidative stress, inflammation and apoptosis

In aquatic animals, hydrogen peroxide (H₂O₂), which is a source of oxidative stress, can cause physiological dysfunction, inflammation, and death. Sanguinarine (SAN) is a plant extract known to improve antioxidant and immune capacity. However, the roles of SAN in H₂O₂-induced liver tissue toxicity is unclear. The effects on hepatic oxidative damage, inflammatory response, and apoptosis were investigated by feeding rice field eel with 0, 375, and 750 μg/kg of SAN for eight weeks and then intraperitoneally injected with H₂O₂. The results showed that after 24 h of H₂O₂ injection, the activities of ALT and AST in serum were significantly increased, oxidative damage and inflammatory response occurred in the liver, and apoptosis was induced, which indicated that H₂O₂ induced liver damage in rice field eel. However, dietary supplemented with 375 or 750 μg/kg SAN significantly decreased the activities of ALT and AST in serum, and significantly increased the antioxidant function (decreased ROS, MDA, and antioxidant enzymes levels, downregulated antioxidant-related gene expression, and inhibited the transcription level of nrf2). The addition of SAN at 375 or 750 μg/kg ameliorated H₂O₂-induced inflammatory response of liver (upregulated tgf-β1 mRNA expression, downregulated il-1β, il-6, il-8, and il-12β mRNA expression, and inhibited the transcription levels of tlr-3 tlr-7, and nf-κb). In addition, dietary supplemented with 375 or 750 μg/kg SAN alleviated the apoptosis of liver induced by H₂O₂ (downregulated bax mRNA expression, upregulated caspase3 mRNA expression, and reduced the number of apoptotic cells by TUNEL staining). Overall, these results suggested that SAN could alleviate the liver injury in rice field eel induced by H₂O₂, mainly by improving antioxidant capacity, alleviating inflammatory response and inhibiting apoptosis, and the effect of 750 μg/kg SAN addition is better than 375 μg/kg.

Modulatory Effect of Papaya Extract against Chlorpyrifos-Induced Oxidative Stress, Immune Suppression, Endocrine Disruption, and DNA Damage in Female Clarias gariepinus

Chlorpyrifos (CPF) is one of the widely used organophosphorus pesticides in agriculture activities and its presence in the aquatic environment has been broadly recorded. In the present study, we investigated the effect of CPF exposure on oxidative stress, innate immunity, sexual hormones, and DNA integrity of female African catfish, Clarias gariepinus, in addition to the potential use of dietary supplementation of papaya, Carica papaya (CP), extract against CPF toxicity. Apparent healthy female catfish (300 ± 10 g) were divided into four groups with three replicates each. The first group served as the negative control (fed on a basal diet) and the other groups exposed to CPF (8.75 µg/L) with or without CP extract (250 mg/kg body weight) for six weeks. The results revealed that CPF exposure exhibited marked elevations in stress markers (glucose and cortisol), serum aspartate aminotransferase, alanine aminotransferase activities, testosterone, and luteinizing hormone level. Moreover, CPF increased the percentage of hepatic DNA damage. In addition, catfish exposed to CPF experienced significant decline in serum total protein, albumin, follicles stimulating hormone, estradiol hormone levels, AChE, immunoglobulin, and lysozyme activity. CPF induced significantly oxidative stress in hepatic and renal tissues. The dietary supplementation with CP extract at a level of 250 mg/kg body weight succeeded to alleviate the negative effects of CPF on the physiological, immunological, and antioxidant status of female catfish. In addition, CP extract alleviated the endocrine disruption and hepatic DNA damage and counteracted the subchronic CPF toxicity in female African catfish. Finally, the CP extract may be used as a feed additive in the aquatic diet.

Antioxidant Activity in Gilthead Seabream (Sparus aurata L.) Fed with Diet Supplemented with Moringa

Gilthead seabream is bred mainly in fish farms in the Mediterranean Sea. One important factor responsible for the deterioration of fish quality is lipid oxidation. Moringa oleifera leaves have been described as having high antioxidant content. This work investigates the effect of dietary supplementation with Moringa leaves on the antioxidant activity of seabream. Gilthead seabream specimens were divided into four groups, the control group (fed a commercial diet) and three other groups fed diets enriched with Moringa (5%, 10% and 15%). The antioxidant capacity was measured by assays of free radical scavenging (OH·, H₂O₂, lipoperoxyl and ABTS), Rancimat test and linoleic acid system in muscle and skin of gilthead seabream, commercial diet, enriched diet and Moringa. Finally, the polyphenol content of Moringa and the fatty acid composition of seabream fed diets with and without Moringa were determined. Results showed an increase in antioxidant activity in gilthead seabream fed with diets enriched with a higher percentage of Moringa; therefore, Moringa could be considered a functional ingredient in diets for fish bred in fish farms and. The antioxidant potential of Moringa leaves could be mainly attributed to the presence of polyphenolic compounds.

The Evaluation of Arthrospira platensis Bioactivity and their Dietary Supplementation to Nile Tilapia Vegetarian Diet on Growth Performance, Feed Utilization, Body Composition and Hemato-Biochemical Parameters

The present study aimed to identify the carotenoid content and evaluate the antioxidant activities of spirulina, Arthrospira platensis (in vitro), and the effect of its supplementation to a vegetarian diet on growth performance, feed utilization, body proximate composition and physiological status of Nile tilapia, Oreochromis niloticus (in vivo). The carotenoid content of spirulina was identified by UPLC-MS/MS and showed that trans and cis β-carotene were the major carotenoids (88.3%) followed by β-cryptoxanthin and zeaxanthin. The antioxidant activity of spirulina was determined in water and crude carotenoid extracts by 2,2-diphenyl-1-picryhydrazyl (DPPH) scavenging assay, both extracts showed a significant free radical scavenging capacity. In addition, Nile tilapia fry (0.83 ± 0.01 g) was fed a vegetarian diet supplemented with different levels of spirulina for 12 weeks. The results revealed that the highest growth performance and nutrient utilization were recorded with 0.5% spirulina and the peak response determined at 0.63%-0.65% using polynomial second order regression. Also, the hemoglobin content improved in a quadratic regression model with the peak at 0.67% spirulina. Plasma total protein and lipid contents increased significantly with spirulina levels over 0.50%. Moreover, the aminopeptidase activities and glucose level decreased significantly with increasing spirulina levels. The current study recommended the supplementation of the Nile tilapia vegetarian diet with spirulina at levels of 0.63-0.65% for better growth performance and physiological status.

The Gene Regulatory Roles of Herbal Extracts on the Growth, Immune System, and Reproduction of Fish

The crucial need for safe and healthy aquatic animals obligates researchers in aquaculture to investigate alternative and beneficial additives. Medicinal herbals and their extracts are compromised with diverse effects on the performances of aquatic animals. These compounds can affect growth performance and stimulate the immune system when used in fish diet. In addition, the use of medicinal herbs and their extracts can reduce oxidative stress induced by several stressors during fish culture. Correspondingly, aquatic animals could gain increased resistance against infectious pathogens and environmental stressors. Nevertheless, the exact mode of action where these additives can affect aquatic animals' performances is still not well documented. Understanding the mechanistic role of herbal supplements and their derivatives is a vital tool to develop further the strategies and application of these additives for feasible and sustainable aquaculture. Gene-related studies have clarified the detailed information on the herbal supplements' mode of action when administered orally in aquafeed. Several review articles have presented the potential roles of medicinal herbs on the performances of aquatic animals. However, this review article discusses the outputs of studies conducted on aquatic animals fed dietary, medicinal herbs, focusing on the gene expression related to growth and immune performances. Furthermore, a particular focus is directed to the expected influence of herbal supplements on the reproduction of aquatic animals.

Immune, inflammatory, autophagic and DNA damage responses to long-term H2O2 exposure in different tissues of common carp (Cyprinus carpio)

Hydrogen peroxide (H₂O₂) is a stable reactive oxygen species (ROS) in aquatic environment, and high concentration of ambient H₂O₂ may directly or indirectly affect aquatic animal health. However, the response mechanism of fish to ambient H₂O₂ has not been well studied yet. Therefore, the aim of the study was to investigate the immune, inflammatory, autophagic and DNA damage responses to long-term H₂O₂ exposure in different tissues of common carp. The results showed that H₂O₂ exposure induced a significant immune response, with alterations in the levels of immune parameters including AKP, ACP, LZM, C3, HSP90 and HSP70 in different tissues. The inflammatory response evoked by H₂O₂ exposure was associated with the activations of TLRs and NF-κB (P65) in the majority of tested tissues. The autophagy process was significantly affected by H₂O₂ exposure, evidenced by the upregulations of the autophagy-related genes in liver, gills, muscle, intestines, heart and spleen and the downregulations in kidney. Meanwhile, the mRNA level of atm, a primary transducer of DNA damage response, was upregulated in liver, gills, intestines and spleen, and the DNA damage was evidenced by increased 8-OHdG level in intestines after H₂O₂ exposure. Moreover, cell cycle regulation-related genes, including cyclin A1, B and/or E1, highly expressed in all tested tissues except heart after H₂O₂ exposure. Interestingly, IBR analysis exhibited that immune, inflammatory, autophagic and DNA damage responses to H₂O₂ exposure were in a dose-dependent and tissue-specific manner. These data may contribute to understanding H₂O₂ toxicity for fish and assessing potential risk of H₂O₂ in aquatic environment.

Chronic exposure of hydrogen peroxide alters redox state, apoptosis and endoplasmic reticulum stress in common carp (Cyprinus carpio)

Hydrogen peroxide (H₂O₂) appears to be ubiquitous in natural water. Higher level of H₂O₂ can cause physiological stress, immunosuppression and even death in aquatic animals, but the physiological and molecular mechanisms of H₂O₂ toxicity are not well studied. Thus, the aim of the present study was to exposure potential toxic mechanisms of H₂O₂ via assessing the effects on redox state, apoptosis and endoplasmic reticulum (ER) stress in common carp. The fish were subjected to four concentrations of H₂O₂ (0, 0.25, 0.5 and 1 mM) for 14 days. And then, the tissues including blood, liver, muscle, gills, intestines, heart, kidney and spleen were collected to measure biochemical parameter and gene expression. The results showed that H₂O₂ exposure suppressed the majority antioxidative parameters in serum, liver, muscle and intestines, but enhanced T-SOD, CAT and T-AOC levels in gills. In all tested tissues, the MDA content was significantly promoted by H₂O₂ exposure. The oxidative stress-related genes including nrf2, gstα, sod, cat and/or gpx1 were upregulated in liver, gills, muscle, intestines, and/or kidney, but downregulated in heart after H₂O₂ exposure. Moreover, the ho-1 mRNA level was inhibited by H₂O₂ exposure in all tissues except intestines and spleen. After 14 days of exposure, H₂O₂ induced ER stress and initiated IRE1 and PERK pathways, which activated downstream genes, including chop, grp78 and/or xbp1s, to regulate UPR in liver, gills, muscle and/or heart. Meanwhile, H₂O₂ exposure activated MAPK pathway to regulate mitochondria-related genes including bcl-2, bax and cytc, which further triggered cas-8, cas-9 and cas-3, and accelerated apoptosis in liver, gills, muscle and heart. Importantly, in different tissues, the genes associated with oxidative stress, ER stress and apoptosis showed a different influence, and more significant influence was observed in the muscle, gills and liver. Overall results suggested that long-term H₂O₂ exposure induced oxidative stress, ER stress and apoptosis in the majority of tested tissues of common carp. The Nrf2, IRE1, PERK and MAPK pathways played important roles in H₂O₂-induced toxicity in fish. These data enriched the toxicity mechanism of H₂O₂ in fish, which might contribute to the risk assessment of H₂O₂ in aquatic environment.

Synergism of Dietary Co-Supplementation with Lutein and Bile Salts Improved the Growth Performance, Carotenoid Content, Antioxidant Capacity, Lipid Metabolism, and Lipase Activity of the Marbled Spinefoot Rabbitfish, Siganus rivulatus

A 60-day feeding trial was conducted to assess the effects of dietary supplementation with bile salts (BS), lutein (LTN), and their combination on growth, survival, carotenoid content, and antioxidant status of rabbitfish (Siganus rivulatus) larvae. Fish were fed four isonitrogenous (34.39% protein) and isoenergetic (20.57 kJ/g) diets supplemented with BS (0.15 g kg^-1), LTN (0.1 g kg^-1), BS+LTN (0.15 and 0.1 g kg^-1, respectively), and a non-supplemented control diet. The results revealed that fish fed BS+LTN had the highest significant specific growth rate (4.37% day^-1), feed efficiency (46.55%), and survival (97.78%). Lutein supplementation improved whole-body protein content, meanwhile, fish fed a BS-supplemented diet had a higher lipid content. The carotenoid deposition was significantly increased with LTN and BS+LTN in skin, muscle, and whole body compared to the control and BS treatment. All dietary supplementation of BS and LTN showed significant improvement in total antioxidant capacity, catalase, and glutathione peroxidase activities. Additionally, LTN alone or BS+LTN significantly reduced malondialdehyde levels by 5.30 and 29.91%, respectively compared to the control. BS supplementation modulated aminopeptidases activities, triglycerides, cholesterol, and increased the activity of pancreatic lipase. Therefore, it could be inferred that dietary supplementation with LTN in combination with BS could improve the growth performance, carotenoid deposition, antioxidant status, lipid digestion, and metabolism of S. rivulatus.