Stimulation of immunity in Indian major carp Catla catla with herbal feed ingredients

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

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

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

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

Anti-vibrio and immune-enhancing activity of medicinal plants in shrimp: A comprehensive review

Disease epidemics in shrimp aquaculture increase apace with the development of aquaculture systems throughout the world. The disease caused by Vibrio spp. (vibriosis) is considered the most devastating, which has made it the most feared bacterial disease in the shrimp sector. In aquaculture, several strategies have already been applied to control Vibrio strains, including chemicals, probiotics, antibiotics, natural products from plants, including plant oils; hence, there has been considerable attention for using plants in shrimp aquaculture to provide sustainable, eco-friendly and safe compounds, such as alkaloids, saponins, terpenoids and flavonoids for replacing chemical compounds and antibiotics in current aquaculture. Medicinal plants may also have immunostimulating activity, increase growth and resistance in shrimps. The present paper aims to review the inhibition of Vibrio spp. in shrimp by medicinal plants, using both in vitro or/and in vivo techniques. Several medicinal plants appear capable of inhibiting growth of Vibrio pathogens outside living shrimp or in the body of shrimp, through enhancing growth and immune capacity when shrimps are fed or injected with them. In the current review Gracilaria spp. (Gracilariaceae family) and Sargassum spp. (family Sargassaceae) have been used most for in vitro and in vivo experiments. Among the terrestrial plants, Eucalyptus camaldulensis, Psidium guajava, Rhodomyrtus tomentosa, and Syzygium cumini (Myrtaceae family) had significant activity against Vibrio.

Impact of dietary leaf extracts of Black pepper Piper nigrum L. on the growth, hematological and immunological parameters of Labeo rohita (Hamilton, 1822) cultured in glass aquaria

A study was conducted to evaluate the effect of Piper nigrum (black pepper) leaf extract on on the growth performance, proximate composition, hematological parameters, and immune response of Labeo rohita fingerlings with an average weight of 22.14 ± 0.98g. Aftrer acclimation for two weeks, fish (n=25) were randomly selected and placed in four glass aquaria (T0, T1, T2 and T3) at constant water temperature (30.0 ± 1.0 °C), pH (7.50 ± 0.5) and total hardness (200 ± 2.0 mgL,-1) for a period of 12 weeks, with three replicates each. Fish were fed with P. nigrum leaf extract supplemented feed @ 0.0%, 1.0%, 2.0% and 3.0% in T0, T1,T2 and T3, respectively. At the end of experiment, five fish were randomly selected from each aquaria for proximate composition, gut and skin microbial load, hematological parameters. Total proteins, albumins, and globulins were also recorded to evaluate immunological memory. The result revealed that fish in T2 showed better growth performance with an average weight gain of 56.11 ± 0.51 g. Thus, it had been concluded that Piper nigrum, a medicinal plant, can also be used to enhance the growth performance and immune response of Labeo rohita as attractive alternatives against antibiotics and vaccines and has shown no negative side effects on fish health as well as on its environment.

Stimulatory effect of dietary chasteberry (Vitex agnus-castus) extract on immunity, some immune-related gene expression, and resistance against Aeromonas hydrophila infection in goldfish (Carassius auratus)

Chasteberry is highly recommended as an herbal medicine across the globe for treating of many gynaecological disorders. In this study, chasteberry extract (CBE) was supplemented in goldfish diet to evaluate the immunity responses at the cellular and molecular levels. Moreover, after the feeding trial, the fish were challenged with Aeromonas hydrophila. The fish (300 individuals, 2.4 ± 0.12 g initial weight) were randomly distributed in 12 tanks and were fed with 0 (control), 5, 10, and 15 g CBE per kg of feed for 8 weeks. Based on the results, lysozyme activity, alkaline phosphatase, and total immunoglobulin (Ig) in the skin mucus samples were significantly enhanced in the fish fed with 15 g/kg CBE (P < 0.05). Moreover, dietary CBE positively affected lysozyme activity, complement components, and IgM content of the serum samples compared to the control group. Also, the number of monocytes and lymphocytes were increased significantly with increasing CBE in the diet (P < 0.05). The highest mRNA levels of tumor necrosis factors (TNF-α, TNF-2α) and Lysozyme were observed in 15 g/kg CBE treatment. After the challenge test, the highest relative percentage survival value (60%) was observed in the fish fed with 15 g/kg CBE. We concluded that dietary CBE especially at 15 g/kg has an immunomodulatory effect in goldfish by stimulating the innate immunity and some inflammatory cytokines as well as disease resistance against A. hydrophila.

Antibacterial synergy between rutin and florfenicol enhances therapeutic spectrum against drug resistant Aeromonas hydrophila

Emergence of antibiotic resistant bacteria has necessitated the drive to explore competent antimicrobial agents or to develop novel formulations to treat infections including Aeromonas hydrophila. The present study investigates the synergistic antibacterial effects of citrus flavonoid rutin and florfenicol (FF) against A. hydrophila in vitro and in vivo. Rutin is extracted and purified from Citrus sinensis peel through preparative HPLC and characterized through TLC, GC-MS and ¹H and ¹³C NMR analyses. Though rutin did not display significant antibacterial activity, it modulated FF activity resulting in four-fold reduction in the MIC value for FF. The anti-biofilm potential of synergistic association of rutin and FF was validated by protein analysis, quantification of exopolysaccharide (EPS) and microscopy studies using sub-MIC doses. Besides antibacterial action, in vivo studies showed that Rutin/FF combination enhanced host immunity by improving blood cell count, anti-protease, and lysozyme activities as well as decreased the oxidative stress and the pathological changes of tilapia Oreochromis niloticus against A. hydrophila infection. No significant DNA damages or clastogenic effects were detected in tilapia challenged with A. hydrophila under Rutin/FF treatment. It is shown that an acute-phase Lipopolysaccharide binding protein (LBP) enhances the innate host defence against bacterial challenge. Semi quantitative RT-PCR and western blot results revealed the significant increase of LBP in the supernatant of tilapia monocytes/macrophages challenged with A. hydrophila upon treatment. The study findings substantiate that the combination of natural molecules with antibiotics may open up possibilities to treat MDR strains.

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

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

Beneficial effects of killed Tsukamurella inchonensis on rainbow trout (Oncorhynchus mykiss) growth, intestinal histology, immunological, and biochemical parameters

Present study was conducted to investigate the effects of heat-killed Tsukamurella inchonensis on growth performance, gastrointestinal structure, immune response, and biochemical parameters in rainbow trout. Fish (mean weight 25 g) were fed basal diet (control), diets containing 2.48 × 10⁸ colony-forming units (low-dose group) or 1.24 × 10⁹ colony-forming units (high-dose group) of heat-killed Tsukamurella inchonensis per 1 kg of feed for 90 days. Results showed that growth performance was significantly enhanced in both treatment groups compared to the control group. The intestinal villus length and pyloric cecal fold length were mainly enhanced in the high-dose group. On the other hand, higher goblet cell percentage was shown with administration of dead Tsukamurella inchonensis in both treatment groups. Immune parameters such as alternative complement activity, immunoglobulin level, and hemagglutination titer were significantly higher in treatment groups than in fish fed in the control diet. Meanwhile, feeding heat-killed Tsukamurella inchonensis especially at higher dose caused a decrease in the levels of total cholesterol, uric acid, and lipid peroxidation product whereas no significant changes were noted in serum-specific marker enzymes levels, namely alanine aminotransferase (ALT), alkaline phosphatase (ALP), and aspartate aminotransferase (AST) by feeding both treatment diets compared to the control group. This study suggests that heat-killed Tsukamurella inchonensis especially at 1.24 × 10⁹ colony-forming units had more potential to enhance growth, immunological parameters, and intestinal structure in rainbow trout.

Role of aloin in the modulation of certain immune parameters in skin mucus of an Indian major carp, Labeo rohita

Enhancement of immune system seems to be the most promising method of preventing fish diseases. Several herbal products have immunostimulant properties, and are environmental friendly, economical and can act against a broad spectrum of pathogens. Present study was designed with an aim to evaluate the role of aloin, extracted from a herb Aloe barbadensis, in the modulation of certain immune parameters in an Indian major carp, Labeo rohita. Fishes were divided into control, vehicle control and aloin treated groups. Experiments were conducted for 7 days and fishes from the three groups were analyzed at 2d, 4d, 6d and 8d. The results demonstrated that at different intervals, L. rohita administered with aloin showed a significant increase in the activity of enzymes - lysozyme, protease, carboxylesterase, alkaline phosphatase, acid phosphatase, catalase and peroxidase, and non-enzymatic factors hemagglutinin and alternate complement compared with that of the controls. Thus, it can be concluded that administration of aloin is beneficial in enhancing the immune response and hence it can be used as potent immunostimulant in aquaculture.

Role of medicinal plants on growth performance and immune status in fish

Disease outbreaks increase proportionally with increases in intensive aquaculture. Natural products including medicinal plants have been known from thousands of years for treating some human diseases. It is well known that many active compounds are responsible for potential bio-activities. For that reason, there has been considerable interest in the use of medicinal plants in aquaculture with a view to providing safe and eco-friendly compounds for replacing antibiotics and chemical compounds as well as to enhance immune status and control fish diseases. This article describes a wide range of medicinal plants such as herbs, seeds, and spices with different forms such as crude, extracts, mixed and active compounds, used as immunostimulants and resulting in a marked enhancement in the immune system of fish to prevent and control microbial diseases. Moreover, different activity was recorded from plant parts like seeds, roots, flowers and leaves. The mode of action of medicinal plants was stimulation of the cellular and humoral immune response which was monitored through elevation in immune parameters. Various levels of immune stimulation have been shown by medicinal plants at different concentrations through injection or immersion or oral administration. However, it is critically important to determine the optimal dose to enhance the immune system of fish and avoid the risk of immunosuppression. Some medicinal plants have been used to replace the protein in fishmeal as a cheap source of protein and proved to be efficient in this respect. Medicinal plants can act as a growth promoter and immunomodulator at the same time. Further investigations should be carried out to examine the influence of those plants on fish health (including physiological and histological parameters) as a preliminary step for use in large scale in aquaculture. The current review describes the role of medicinal plants and their derivatives on innate and adaptive immune status as well as growth performance in fish.

Oreochromis mossambicus diet supplementation with Psidium guajava leaf extracts enhance growth, immune, antioxidant response and resistance to Aeromonas hydrophila

In this research, we focused on the efficacy of aqueous and ethanol leaf extracts of Psidium guajava L. (guava) based experimental diets on the growth, immune, antioxidant and disease resistance of tilapia, Oreochromis mossambicus following challenge with Aeromonas hydrophila. The experimental diets were prepared by mixing powdered (1, 5 and 10 mg/g) aqueous and ethanol extract of guava leaf with commercial diet. The growth (FW, FCR and SGR), non-specific cellular immune (myeloperoxidase activity, reactive oxygen activity and reactive nitrogen activity) humoral immune (complement activity, antiprotease, alkaline phosphatase activity and lysozyme activity) and antioxidant enzyme responses (SOD, GPX, and CAT) were examined after 30 days of post-feeding. A significant enhancement in the biochemical and immunological parameters of fish were observed fed with experimental diets compared to control. The dietary supplementation of P. guajava leaf extract powder for 30 days significantly reduced the mortality and increased the disease resistance of O. mossambicus following challenge with A. hydrophila at 50 μl (1 × 10⁷ cells ml^-1) compared to control after post-infection. The results suggest that the guava leaf extract could be used as a promising feed additive in aquaculture.

Methanol extract of Nyctanthes arbortristis seeds enhances non-specific immune responses and protects Oreochromis mossambicus (Peters) against Aeromonas hydrophila infection

Immunostimulation using medicinal plant extracts is a promising approach for prevention and control of diseases with reference to sustainable fish farming. Oreochromis mossambicus, dubbed as aquatic chicken is a cultured fish worldwide and a laboratory model organism. Aeromonas hydrophila is one of the major bacterial pathogens in fish farming that causes huge loss to aquaculture industries. In this study, we investigated the efficacy of methanol extract of Nyctanthes arbortristis seeds on disease resistance of O. mossambicus against live virulent A. hydrophila. We also investigated its effect on the non-specific immune parameters such as serum lysozyme, myeloperoxidase, antiprotease and specific immune parameters in terms of specific serum antibody titres assayed by bacterial agglutination test. Our studies indicate that intra-peritoneal administration of 20mg/kg methanol extract increases the Relative Percent Survival (RPS) of O. mossambicus challenged with LD80 of A. hydrophila. Further, both non-specific and specific immune parameters were enhanced by the methanol extract. Further experiments at molecular levels in the laboratory and also efficacy testing at field level are essential before applying this plant product in aquaculture industry.

Effects of fenugreek (Trigonella foenum graecum) on gilthead seabream (Sparus aurata L.) immune status and growth performance

The possible effect of dietary administration of fenugreek (Trigonella foenum graecum) on gilthead seabream (Sparus aurata L.) immune status and growth performance was studied. Fish were divided into 4 groups before being fed with commercial diet supplemented with 0% (control), 1%, 5% and 10% of fenugreek seeds for 4 weeks. The effects of the diets were analysed on the cellular (respiratory burst activity and leucocyte peroxidase content) and humoral (complement activity, antiprotease, total protein, peroxidase, and IgM level) immune parameters, as well as growth and haematological parameters (WBC and RBC counts). The results recorded enhancement in all the assayed parameters in fish fed fenugreek diets comparing to control fish. The expression of several immune-related genes in head-kidney (MHC1, CSF-1R, IL-8, and IgM) and different antioxidant enzyme genes in liver (GR, CAT and SOD) of seabream specimens were also investigated. Again, the highest fenugreek doses tested provoked significant up-regulation in most of immune-related genes and antioxidant enzyme genes (p < 0.05). No adverse effects were observed on intestine and liver morphology on fish fed fenugreek diets. The present results suggest that the fenugreek seed, specially the highest dosage used in the present work could be considered a good food supplement to improve the immune status and increase the production of gilthead seabream.

Influence of extremely low frequency electromagnetic fields on growth performance, innate immune response, biochemical parameters and disease resistance in rainbow trout, Oncorhynchus mykiss

The effects of extremely low frequency electromagnetic fields on rainbow trout growth performance, innate immunity and biochemical parameters were studied. Rainbow trout (17-18 g) were exposed to electromagnetic fields (15 Hz) at 0.01, 0.1, 0.5, 5 and 50 µT, for 1 h daily over period of 60 days. Growth performance of fish improved in different treatment groups, especially at 0.1, 0.5, 5 and 50 µT. Immunological parameters, specifically hemagglutinating titer, total antiprotease and α1-antiprotease levels in treatment groups, were also enhanced. Total protein and globulin contents in the serum of fish exposed to 0.1, 0.5, 5 and 50 µT were significantly higher than those in the control group. No significant differences were found in serum enzyme activities, namely aspartate aminotransferase and alanine aminotransferase of fish in all treatment groups. Conversely, alkaline phosphatase level decreased in fish exposed to 0.01 and 50 µT electromagnetic fields. Meanwhile, electromagnetic induction at 0.1, 0.5, 5 and 50 µT enhanced fish protection against Yersinia ruckeri. These results indicated that these specific electromagnetic fields had possible effects on growth performance, nonspecific immunity and disease resistance of rainbow trout.

Acute inflammation and hematological response in Nile tilapia fed supplemented diet with natural extracts of propolis and Aloe barbadensis

This study evaluated the acute inflammatory response induced by carrageenin in the swim bladder of Nile tilapia supplemented with the mixture of natural extracts of propolis and Aloe barbadensis (1:1) at a concentration of 0.5%, 1% and 2% in diet during 15 days. Thirty-six fish were distributed into four treatments with three replicates: fish supplemented with 0.5% of admix of extracts of propolis and Aloe (1:1) injected with 500 µg carrageenin; fish supplemented with 1% of admix of extracts of propolis and Aloe (1:1) injected with 500 µg carrageenin; fish supplemented with 2% of admix of extracts of propolis and Aloe (1:1), injected with 500 µg carrageenin and unsupplemented fish injected with 500 µg carrageenin. Six hours after injection, samples of blood and exudate from the swim bladder of fish were collected. It was observed an increase in the leukocyte count in the swim bladder exudate of fish supplemented with extracts of propolis and Aloe injected with carrageenin. The most frequent cells were macrophages followed by granular leukocytes, thrombocytes and lymphocytes. Supplementation with propolis and Aloe to 0.5% caused a significant increase in the number of cells on the inflammatory focus mainly macrophages, cells responsible for the phagocytic activity in tissues, agent of innate fish immune response.

Effects of dihydroquercetin obtained from deodar (Cedrus deodara) on immune status of gilthead seabream (Sparus aurata L.)

The use of medicinal plants as prophylactic method in fish is considered safe and a very promising alternative to the use of chemicals in aquaculture practices. The prospective mode of action of dihydroquercetin, fraction of the medical plant deodar (Cedrus deodara), was evaluated on immune status of gilthead seabream (Sparus aurata L.). Fish were divided into 4 groups before being fed for 14 days with commercial diets supplemented with 0% (control), 0.1%, 0.5% and 1% of dihydroquercetin. Cellular (phagocytosis and respiratory burst activities) and humoral (seric complement activity, antiprotease, total protein, peroxidase, bactericidal activity and IgM level) immune parameters were investigated. The results recorded enhancement in all the tested parameters and in all the dihydroquercetin supplemented groups compared to the control. Interestingly, the fish received the lowest dose of dihydroquercetin (0.1%) showed a highly significant difference (p < 0.05) in phagocytosis, respiratory burst, IgM level, total protein, complement, antiprotease and bactericidal activities compared to the control. Direct effect of different doses of dihydroquercetin on head-kidney leucocytes was also studied in a previous in vitro assay. Again, the lowest doses tested provoked the highest immune cellular activities, where, the highest phagocytic and respiratory bust activities were recorded in leucocytes incubated with 0.025% and 0.0125% doses, respectively. Therefore, the results suggest that low concentrations of dihydroquercetin as food supplements are able to increase the immune status of gilthead seabream.

Effects of dietary katuk (Sauropus androgynus L. Merr.) on growth, non-specific immune and diseases resistance against Vibrio alginolyticus infection in grouper Epinephelus coioides

This study was conducted to investigate the effect of katuk (Sauropus androgynus L. Merr) on growth, non-specific immune and diseases resistance against Vibrio alginolyticus in grouper (Epinephelus coioides). Grouper juveniles (mean weight 10.97 ± 1.99 g, and length 9.67 ± 0.33 cm) were separated into four groups and cultivated in 100-L tank. Each group was fed with diets containing 0, 1.0, 2.5 and 5.0 g/kg herbs diet twice daily. Fish were sampled for non-specific immune parameters at 0, 1, 2, 4, 7, 14 and 30 days. Results showed that fish received S. androgynus at 1.0 and 2.5 g/kg diets affected the growth and non-specific immune responses. Weight gain, specific growth rate, respiratory burst activity, phagocytosis and reactive oxygen species significantly increased in fish administered with 1.0 and 2.5 g/kg S. androgynus diets. The mortality rate after V. alginolyticus challenge decreased in fish fed with 1.0 g/kg S. androgynus extract. Thus, this study indicated that administration of grouper with S. androgynus supplemented diets can affect the growth performances, diseases resistance and enhances non-specific immune responses.

WITHDRAWN: Dietary supplementation of Artemisia capillaris on immunity in Paralichthys olivaceus against Edwardsiella tarda

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Inonotus obliquus containing diet enhances the innate immune mechanism and disease resistance in olive flounder Paralichythys olivaceus against Uronema marinum

The present study describes the effect of diet supplementation with Chaga mushroom, Inonotus obliquus extract at 0%, 0.01%, 0.1%, and 1.0% levels on the innate humoral (lysozyme, antiprotease, and complement), cellular responses (production of reactive oxygen and nitrogen species and myeloperoxidase), and disease resistance in olive flounder, Paralichythys olivaceus against Uronema marinum. The lysozyme activity and complement activity significantly increased in each diet on weeks 2 and 4 against pathogen. The serum antiprotease activity and reactive nitrogen intermediates production significantly increased in fish fed with 0.1% and 1.0% diets from weeks 1-4. However, reactive oxygen species production and myeloperoxidase activity significantly increased in 1.0% and 2.0% diets on weeks 2 and 4. In fish fed with 0.1% and 1.0% diets and challenged with U. marinum the cumulative mortality was 50% and 40% while in 0% and 0.01% diets the mortality was 85% and 55%. The results clearly indicate that supplementation diet with I. obliquus at 0.1% and 1.0% level positively enhance the immune system and confer disease resistance which may be potentially used as an immunoprophylactic in finfish culture.

Effect of Coriolus versicolor supplemented diet on innate immune response and disease resistance in kelp grouper Epinephelus bruneus against Listonella anguillarum

The effect of Coriolus versicolor extract supplemented diets on innate immune response and disease resistance in kelp grouper, Epinephelus bruneus against Listonella anguillarum, is reported. Kelp grouper were divided into four groups of 25 each and fed with C. versicolor enriched diets at 0% (control), 0.01%, 0.1%, and 1.0% level. After 30 days of feeding, all fish were injected interaperitoneally (i.p.) with 50 μl of L. anguillarum (4.7 × 10(7) CFU) to investigate the immune parameters at weeks 1, 2, and 4. The reactive oxygen species and reactive nitrogen species production were significantly enhanced in fish fed with 0.1% and 1.0% supplementation diets from weeks 1-4 when compared to the non enriched diet fed and infected control. The phagocytic activity significantly increased with 0.1% and 1.0% diets on weeks 2 and 4. The leucocyte myeloperoxidase content, lysozyme activity, and total protein level significantly increased when fed with 0.1% and 1.0% supplementation diets from weeks 1-4. The cumulative mortality was 35% and 45% in 1.0% and 0.1% enriched diet fed groups whereas it was 55% and 80% in 0.01% and 0% groups respectively. The present results suggest that diets enriched with C. versicolor at 0.1% or 1.0% level positively enhance the innate immune system and affords protection from L. anguillarum.

Kalopanax pictus as feed additive controls bacterial and parasitic infections in kelp grouper, Epinephelus bruneus

Feeding kelp grouper, Epinephelus bruneus (26.1 ± 1.4), with 0%, 0.1%, 1.0%, and 2.0% Kalopanax pictus extract-supplementation diets, for 30 days reduced mortality on being challenged intraperitoneally 100 μl with bacterium Vibrio alginolyticus (2.1 × 10(7) cfu ml(-1)) and ciliate parasite Philasterides dicentrarchi (2.3 × 10(7) ciliates ml(-1)). The red blood cells (RBC), white blood cells (WBC), haemoglobin, haematocrit, lymphocytes, and monocytes levels significantly increased in kelp grouper fed with all doses of K. pictus-supplementation diets and challenged with bacterium and parasite when compared to control. However, the levels of mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), neutrophils, and thrombocytes did not significantly. The phagocytic activity, complement activity, and antiprotease activity did not significantly change in kelp grouper fed with 0.1% K. pictus-supplementation diets and challenged with bacterium and parasite. The respiratory activity, lysozyme activity, bactericidal activity, total protein level, and myeloperoxidase levels significantly increased in kelp grouper fed with all the doses of K. pictus-supplementation diet and challenged with bacterium and parasite. However, α2-macroglobulin level significantly increased with 1.0% diet, but not with 0.1% and 2.0% diets. Therefore this study suggests that 1.0% and 2.0% K. pictus-supplementation diets positively protected and enhanced the immune system in kelp grouper E. bruneus against V. alginolyticus and P. dicentrarchi infection.

Immunomodulatory effects of decaffeinated green tea (Camellia sinensis) on the immune system of rainbow trout (Oncorhynchus mykiss)

In order to study the immunomodulatory effects of decaffeinated green tea extract on rainbow trout, a study with a 30-day feeding trial was conducted. Commercial diets with graded levels of decaffeinated green tea extract, 20 mg (T1), 100 mg (T2), 500 mg (T3) per kg feed were prepared. 120 rainbow trout (35 ± 3 g) were randomly assigned to 4 groups in triplicates and fed one of the 3 experimental diets formulated or control diet. After feeding trial, 12 fish from each group were sampled for analysis of some immunological parameters. Remaining fish were injected with 0.5 ml of chicken red blood cell (C-RBC) suspension (2%) intraperitoneally on days 5 and 15 after feeding trial. Results of the current study showed that the inclusion of 20 mg kg-1 green tea (T1) in fish diet enhanced the serum bactericidal activity against Yersinia ruckeri, while significant elevation of lysozyme activity was shown in T2 group. Anti-trypsin activity due to α1-antiprotease was significantly higher in T1 and T2 groups while peroxidase content showed significant increase in all treatment groups compared to control group. Hemagglutination antibody titer against C-RBC was significantly higher in fish administered with 100 mg kg(-1) green tea (T2). Our findings showed that decaffeinated green tea in lower doses of administration could be optimum to enhance the immunity of rainbow trout.

Dietary supplementation with Cynodon dactylon (L.) enhances innate immunity and disease resistance of Indian major carp, Catla catla (Ham.)

Indian major carp (Catla catla) was subjected to study the immunostimulatory effects when the grass Cynodon dactylon(L) ethanolic extract administrated as feed supplement. C. catla was fed with 0% (Control), 0.05% (group I), 0.5% (group II) and 5% (group III) extract provided for 60 days. Blood samples were collected at every 10 days of interval up to 60 days for analyzing the non-specific humoral (lysozyme activity, antiprotease activity and haemolytic complement) and cellular (production of reactive oxygen and nitrogen species, myeloperoxidase activity) immune response study. The results indicate that C. dactylon ethanolic extract administered as feed supplement significantly (P < 0.05) enhanced most of the non-specific immune parameters tested. Among the experimental diet groups, significantly increased response of non-specific immunity was seen in group III (5%). Disease resistant analysis against Aeromonas hydrophila was performed in control group and plant extract treated fish for 7, 14, 21 and 28 days. Relative percent survival rate (RPS) was observed in treated samples, which is directly proportional to concentration of the extract. Additionally, electron microscopic studies and gelatin zymography for Matrix Metalo Proteinase (MMPs) were examined in spleen at 7th and 28th days of feeding. Administration of C. dactylon mixed diet delayed the lymphocyte destruction with positive ultrastructural changes. An induced stress (A. hydrophila infection) was observed by using MMPs expression, which was reduced in the experimental diet groups than the control. All these experimental results prove that C. dactylon ethanolic extract enhances the immunity of Catla fish.

Effects of long-term silymarin oral supplementation on the blood biochemical profile of rainbow trout (Oncorhynchus mykiss)

Silymarin, an extract from "milk thistle" (Silybum marianum) plant is traditionally used as herbal medicine. The present study was conducted to investigate the clinical effects and possible side effects of silymarin on biochemical blood parameters of rainbow trout (Oncorhynchus mykiss). Fishes were treated with 0 (control), 100, 400, and 800 mg of silymarin per kg of food during 4 weeks. Plasma alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), alkaline phosphatase (ALP), creatine kinase (CK), glucose, total protein, creatinine, triglyceride, cholesterol, urea, uric acid and liver cellular total antioxidant, and protein content were measured after 7, 14, and 28 days of silymarin treatment. The results showed that oral administration of silymarin in fish significantly reduced plasma glucose and cholesterol levels and relatively increased plasma total protein and globulin concentrations (P < 0.05). Increasing plasma albumin levels indicate the important role of albumin in drug transportation in circulatory system of fish. Silymarin also stabilized cellular membrane structure and regulated the levels of AST, ALT, ALP, CK, and LDH activity. In conclusion, on the basis of these results, oral administration of silymarin up to 400 mg per 1 kg of food has no side effect on blood biochemical and clinical parameters of fishes. However, oral administration of 800 mg/kg- of silymarin caused cytotoxicity and modifications in blood biochemical parameters of fish.

Protective effect of herbal and probiotics enriched diet on haematological and immunity status of Oplegnathus fasciatus (Temminck & Schlegel) against Edwardsiella tarda

This study determines the effect of diet enriched with the herb Baical skullcap Scutellaria baicalensis, and/or probiotics Lactobacillus sakei BK19 in rock bream, Oplegnathus fasciatus (32 ± 3 g) against Edwardsiella tarda. The changes in haematological parameters, innate immune response, and disease resistance were investigated after 1, 3, and 6 weeks. The white blood cell count (WBC: 10(4) mm(-3)), red blood cell count (RBC: 10(6) mm(-3)), and haemoglobin (Hb: g dl(-1)) levels significant increased (P < 0.05) with mixed diet on 3rd and 6th week and probiotics enriched diet on 6th week. The haematocrit (Ht: %) level significantly increased (P < 0.05) when fed with mixed diet on weeks 1-6. Interestingly, in mixed diet group the lymphocytes (LYM), monocytes (MON), and neutrophils (NEU) significantly increased from week 1-6. The eosinophils (EOS) significantly increased in all the treated groups. In the probiotics or mixed diet groups the total protein (TP: g dl(-1)) increased significantly on weeks 3 and 6. The serum lysozyme activity significantly was enhanced in all the treated groups indicating an increase in the innate immunity level. Serum complement, antiprotease activities, reactive oxygen species (ROS) and reactive nitrogen species (RNS) production significantly increased from week 1-6 with mixed diet. The maximum protection against E. tarda was recorded in mixed diet group with a minimum cumulative mortality of 20% and a high relative percent survival (RPS) of 72.84. In the probiotics and herbal diet groups the cumulative mortality was 25% and 35% and RPS was 68.63 and 59.42, respectively. This study indicates that administration of probiotics or mixed diets can effectively minimize the mortality and restore the altered hematological parameters and enhancing the innate immunity in O. fasciatus against E. tarda.

Influence of diet enriched with green tea on innate humoral and cellular immune response of kelp grouper (Epinephelus bruneus) to Vibrio carchariae infection

Effect of diet enriched with green tea at 0, 0.01, 0.1 or 1.0% levels on immune responses such as non-specific humoral (lysozyme, antiprotease and complement) and cellular (myeloperoxidase content, production of reactive oxygen, and nitrogen species) and disease resistance on week 1, 2 or 4 in kelp grouper Epinephelus bruneus challenged with Vibrio carchariae (2.47 × 10(8) CFU ml(-1)) was quantified. At all doses green tea supplementation significantly enhanced the serum lysozyme activity from weeks 1 to 4. On the other hand, after week 2 the serum hemolytic complement activity, leucocyte myeloperoxidase content and reactive nitrogen species protection significantly increased in groups fed with 0.01 and 0.1% green tea supplementation diets. The serum antiprotease activity significantly increased in group fed with at 1.0% green tea from week 1 to 4. However, all diets except at 0.01% level resulted in a significant decrease in reactive oxygen species protection during the experimental period. Challenged groups fed with green tea enriched diet at 0.01 and 0.1% level had a higher relative percent survival than with 1.0% diet on week 1, 2 or 4. The results suggest that dietary administration of green tea supplementation at a concentration of 0.01 and 0.1% level positively enhances the non-specific humoral and cellular immune responses and disease resistance of kelp grouper E. bruneus to V. carchariae.

Immunomodulatory activity of Aegle marmelos in freshwater fish (Catla catla) by non-specific protection

CONTEXT

The production of fish is limited by infectious diseases; when a fish grows in an immunosuppressed condition, it becomes highly susceptible to disease.

OBJECTIVE

The present research work investigates immunomodulatory action of Aegle marmelos (Linn.) Corr. Serr. (Rutaceae) in Catla catla Hamilton (Cyprinidae) for enhancing immune protection of the fish against bacterial infections.

MATERIAL AND METHODS

Doses of 0, 5, 10, 15, 20, 25 and 30 g aqueous plant leaf extract/kg feed were administered orally to the freshwater fish, Catla catla for a period of 30 days to investigate its efficiency to enhance the non-specific immune responses against the fish pathogen Pseudomonas aeruginosa (Schröter) Migula (Pseudomonadaceae).

RESULTS AND DISCUSSION

The fish were challenged with pathogens through water medium for 30 days and the immunomodulatory effect of the Aegle marmelos was evaluated on the blood samples every 5 days until 15 days after infection. The results obtained from the study shows that the 25 g leaf extract/kg of feed was found to be competent to enhance optimum immune response. The effectiveness of the immunostimulant action was found to be best for the first 5 days after challenging with pathogen and subsequently, the immune response was found to decline in all the concentrations of plant extract.

CONCLUSION

The results of the study will be helpful for further investigation in the field to improve the immunocompetence of fish against bacterial pathogens.

Use of lupin, Lupinus perennis, mango, Mangifera indica, and stinging nettle, Urtica dioica, as feed additives to prevent Aeromonas hydrophila infection in rainbow trout, Oncorhynchus mykiss (Walbaum)

Feeding rainbow trout, Oncorhynchus mykiss (Walbaum), with 1% lupin, Lupinus perennis, mango, Mangifera indica, or stinging nettle, Urtica dioica, for 14 days led to reductions in mortality after challenge with Aeromonas hydrophila. In addition, there was significant enhancement in serum bactericidal activity, respiratory burst and lysozyme activity in the treatment groups compared to the controls. Use of lupin and mango led to the highest number of red blood and white blood cells in recipient fish, with use of stinging nettle leading to the highest haematocrit and haemoglobin values; the highest value of mean corpuscular volume and haemoglobin was in the control groups and those fed with stinging nettle.

Innate immune response and disease resistance in Carassius auratus by triherbal solvent extracts

This study reports the effect of aqueous, ethanol and methanol triherbal solvent extract from Azadirachta indica, Ocimum sanctum and Curcuma longa on innate immune mechanisms such as phagocytosis activity, respiratory burst activity, alternative complement activity and lysozyme activity and disease resistance in goldfish (Carassius auratus) against Aeromonas hydrophila. Fish were intraperitoneally injected with different doses of 0, 5, 50 and 100 mg kg(-1) body weight of each triherbal solvent extracts. The functional immunity in terms of percentage mortality and Relative Percent Survival (RPS) and innate immune response was assessed on week 1, 2 and 4 by challenging with live A. hydrophila (1 x 10(7) cells ml(-1)). All the chosen innate immune parameters were enhanced in the ethanol and methanol triherbal solvent extract treatment after week 2. However, the aqueous triherbal extract was enhanced only after week 4. The ethanol and methanol triherbal solvent extracts administration preceding the challenge with live A. hydrophila decreased the percentage mortality in the experimental groups with the consequence increase in RPS values. The study indicates that all the doses of ethanol or methanol triberbal solvent extracts could be positively influence the immune response and protect the heath status of goldfish against A. hydrophila infection.

Dietary medicinal plant extracts improve growth, immune activity and survival of tilapia Oreochromis mossambicus

The effects of supplementing diets with acetone extract (1% w/w) from four medicinal plants (Bermuda grass Cynodon dactylon, H(1), beal Aegle marmelos, H(2), winter cherry Withania somnifera, H(3) and ginger Zingiber officinale, H(4)) on growth, the non-specific immune response and ability to resist pathogen infection in tilapia Oreochromis mossambicus were assessed. In addition, the antimicrobial properties of the extract were assessed against Vibrio alginolyticus, Vibrioparahaemolyticus, Vibrio mimicus, Vibrio campbelli, Vibrio vulnificus, Vibrio harveyi and Photobacterium damselae. Oreochromis mossambicus were fed 5% of their body mass per day for 45 days, and those fed the experimental diets showed a greater increase in mass (111-139%) over the 45 days compared to those that received the control diet (98%). The specific growth rate of O. mossambicus fed the four diets was also significantly greater (1.66-1.93%) than control (1.52%) diet-fed fish. The blood plasma chemistry analysis revealed that protein, albumin, globulin, cholesterol, glucose and triglyceride levels of experimental fish were significantly higher than that of control fish. Packed cell volume of the blood samples of experimental diet-fed fish was also significantly higher (34.16-37.95%) than control fish (33.0%). Leucocrit value, phagocytic index and lysozyme activity were enhanced in fish fed the plant extract-supplemented diets. The acetone extract of the plants inhibited growth of Vibrio spp. and P. damselae with extracts from W. somnifera showing maximum growth inhibition. A challenge test with V. vulnificus showed 100% mortality in O. mossambicus fed the control diet by day 15, whereas the fish fed the experimental diets registered only 63-80% mortality at the end of challenge experiment (30 days). The cumulative mortality index for the control group was 12,000, which was equated to 1.0% mortality, and accordingly, the lowest mortality of 0.35% was registered in H(4)-diet-fed group.

Oral administration of Eclipta alba leaf aqueous extract enhances the non-specific immune responses and disease resistance of Oreochromis mossambicus

Immunostimulatory effects of the oral administration of the medicinal plant, Eclipta alba leaf extracts was studied in tilapia, Oreochromis mossambicus. For this purpose, fish were fed for 1, 2 or 3 weeks with diets containing E. alba leaf aqueous extract at 0, 0.01, 0.1 or 1% levels. After each week, non-specific humoral (lysozyme, antiprotease and complement) and cellular (myeloperoxidase content, production of reactive oxygen and nitrogen species) responses and disease resistance against Aeromonas hydrophila were determined. The results indicated that E. alba aqueous extract administered as feed supplement significantly enhanced most of the non-specific immune parameters tested. Among the humoral responses, lysozyme activity significantly increased after feeding with aqueous extract for 1, 2 or 3 weeks. No significant modulation was noticed in all the cellular responses tested after 3 weeks of feeding, while reactive oxygen species production and myeloperoxidase content showed significant enhancement after 1 week of feeding with aqueous extract. When challenged with A. hydrophila after 1, 2 or 3 weeks of feeding, the percentage mortality was significantly reduced in the treated fish. The highest dose of 1% gave better protection than the other doses with the relative percentage survival (RPS) values of 64, 75 and 32 after feeding for 1, 2 and 3 weeks respectively. The results indicate that dietary intake of E. alba aqueous leaf extract enhances the non-specific immune responses and disease resistance of O. mossambicus against A. hydrophila.

Enhancement of nonspecific immunity and disease resistance in Oreochromis mossambicus by Solanum trilobatum leaf fractions

The purpose of this study was to determine the effect of water and hexane soluble fractions of the Indian medicinal plant, Solanum trilobatum on the nonspecific immune mechanisms and disease resistance in Oreochromis mossambicus. Fish were intraperitoneally injected with different doses of 0, 4, 40 or 400 mg kg(-1) body weight of water or hexane soluble fraction. The nonspecific immune mechanisms were assessed in terms of serum lysozyme activity, reactive oxygen species production and reactive nitrogen species production by peripheral blood leucocytes. The functional immunity in terms of percentage mortality and Relative Percent Survival (RPS) was assessed by a challenge with live Aeromonas hydrophila. Almost all the doses of both water and hexane soluble fractions enhanced the serum lysozyme activity. All the doses of water soluble fraction significantly enhanced the ROS production on most of the days tested. In hexane soluble fraction treated groups, the enhancement in the ROS production was observed at least on 2 days. All the doses of water soluble fraction significantly enhanced the production of RNS only on one day. The RNS production was enhanced significantly only in the group treated with 40 mg kg(-1) of hexane fraction. The leaf fraction administration preceding the challenge with live A. hydrophila, decreased the percentage mortality in the experimental group with the consequent increase in RPS values. This preliminary study indicates that S. trilobatum could be used to promote the health status of fish in intensive finfish aquaculture.

Achyranthes aspera stimulates the immunity and enhances the antigen clearance in Catla catla

Achyranthes aspera, an Indian medicinal plant (family: Amaranthaceae) was incorporated in artificial fish diet, and fed to catla Catla catla. After 4 weeks of feeding, fish were immunized with bovine serum albumin (BSA), spleen and blood were sampled on weekly intervals for four times after immunization. Antigen-specific antibody level in serum was determined by ELISA. Antigen clearance was determined in spleen by immuno-electron microscopy. Achyranthes has significantly (P<0.05) enhanced the BSA-specific antibody titers than the untreated control group throughout the study period. The efficiency of antigen clearance was also enhanced in C. catla treated with Achyranthes.