The Effect of Black Cumin Seeds, Nigella sativa, on the Immune Response of Rainbow Trout, Oncorhynchus mykiss

Effect of Dietary Origanum onites on Growth, Non Specific Immunity and Resistance against Yersinia ruckeri of Rainbow Trout ( Oncorhynchus mykiss)

Natural substances has been identified to maintain health and improve growth performance in the aquaculture. The effect of Origanum onites on growth and immune response of rainbow trout was investigated. Experimental groups (A and B) of 70 fish were separated into 10 different treatments. A groups were fed with dietary administration of O. onites essential oil (0.5 mL kg-1 and 3.0 mL kg-1) and crude powder (1.0 g kg-1 and 10.0 g kg-1) for a period of 8 weeks. Other groups (B) were vaccinated against Yersinia ruckeri at the beginning of experiment and then fed the same diets described above. Results showed that feed conversion ratio in fish fed a combination of O. onites and vaccine was statistically better than the control. NBT-positive cells, phagocytic activity, serum lysozyme activity and immunoglobulin M level were stimulated in both non vaccinated and vaccinated fish (p<0.05). Cumulative mortality in fish fed O. onites was lower than controls following challenge with Y. ruckeri. No mortality was observed in vaccinated fish fed with 0.5 mL kg-1 of O. onites. These results indicated that dietary administration of O. onites could act as an enhanced non specific immune response, growth performance and resistance to Y. ruckeri.

Impacts of dietary zinc oxide nanoparticles on the growth and immunity of Nile tilapia could be ameliorated using Nigella sativa oil

BACKGROUND

Zinc nanoparticles are documented to be harmful to fish because their accumulation in fish bring about many irreversible changes in their health. Nigella sativa and its oil have been endorsed in aquaculture to improve fish health.

METHODS

Two hundred seventy experimental fish (113 ± 5 g body weight) were divided into 6 groups G1-6; control fish fed a diet without any treatment (G1), 0.3% of NSO (G2), 0.5% of NSO (G3), ZnO NPs (40 mg/kg diet) (G4), 0.3% of NSO and ZnO NPs (40 mg/kg diet) (G5), 0.5% of NSO and ZnO NPs (40 mg/kg diet) (G6), the trial lasted for six weeks.

RESULTS

Growth performance was enhanced in fish received diets containing NSO, final weight (FW), weight gain (WG), daily weight gain (DWG), and relative growth rate (RGR) were significantly increased with lower food conversion ratios (FCR) compared to the control. The hepatic glutathione peroxidase (GPx), catalase (CAT), and metallothionein (MT) were increased in response to ZnO NPs stress and only 0.5% NSO supplementation could ameliorate such increment. The immune-related genes [interleukin1-beta (IL-1β), tumor necrosis factor-beta (TNF-β), transforming growth factor-beta 2 (TGF-β2) and C-type lysozyme] as well as growth-related gene [insulin-like growth factor 1 (IGF1)] in liver showed an upregulation in fish fed with NSO diets. Administration of ZnO NPs lowered the resistance of Oreochromis niloticus against bacterial infection with Aeromonas hydrophila and NSO could enhance the immunity in the highest tested concentration (0.5%) (G₆).

CONCLUSIONS

The obtained results implied that NSO could enhance the oxidative and immune status of O. niloticus which could compensate ZnO NPs stress as well as experimental infection of a virulent strain of A. hydrophila. Our results revealed that NSO might increase fish growth and immunity only at a high dose (0.5%).

Immune profiling of rainbow trout (Oncorhynchus mykiss) exposed to Lactococcus garvieae: Evidence in asymptomatic versus symptomatic or vaccinated fish

Lactococcosis, caused by the Gram-positive bacterium Lactococcus garvieae, is a major concern in rainbow trout (Oncorhynchus mykiss) farms, which are regularly affected by outbreaks especially during the summer/fall months. In these farms, unvaccinated healthy and symptomatic fish can coexist with vaccinated fish. In the present study, innate (leukogram, serum lysozyme activity, peroxidase activity, antiprotease activity, bactericidal activity, total IgM and total proteins), and specific immune parameters (serum antibodies to L. garvieae) were assessed in unvaccinated adult rainbow trout naturally exposed to the pathogen, with or without evidence of clinical signs, or subjected to vaccination. Blood was drawn from all three groups, and blood smears were prepared. Bacteria were found in the blood smears of 70% of the symptomatic fish but not in any of the asymptomatic fish. Symptomatic fish showed lower blood lymphocytes and higher thrombocytes than asymptomatic fish (p ≤ .05). Serum lysozyme and bactericidal activity did not vary substantially among groups; however, serum antiprotease and peroxidase activity were significantly lower in the unvaccinated symptomatic group than in the unvaccinated and vaccinated asymptomatic groups (p ≤ .05). Serum total proteins and total immunoglobulin (IgM) levels in vaccinated asymptomatic rainbow trout were significantly higher than in unvaccinated asymptomatic and symptomatic groups (p ≤ .05). Similarly, vaccinated asymptomatic fish produced more specific IgM against L. garvieae than unvaccinated asymptomatic and symptomatic fish (p ≤ .05). This preliminary study provides basic knowledge on the immunological relationship occurring between the rainbow trout and L. garvieae, potentially predicting health outcomes. The approach we proposed could facilitate infield diagnostics, and several non-specific immunological markers could serve as reliable indicators of the trout's innate ability to fight infection.

Nigella sativa seeds mitigate the hepatic histo-architectural and ultrastructural changes induced by 4-nonylphenol in Clarias gariepinus

Due to its prevalence in aquatic environments and potential cytotoxicity, 4-nonylphenol (4-NP) has garnered considerable attention. As a medicinal plant with numerous biological activities, Nigella sativa (black seed or black cumin) seed (NSS) is widely utilized throughout the world. Consequently, this study aimed to examine the potential protective effects of NSS against 4-NP-induced hepatotoxicity in African catfish (Clarias gariepinus). To achieve this objective, 18 fish (351 ± 3 g) were randomly divided into three equal groups for 21 days. The first group serves as a control which did not receive any treatment except the basal diet. The second and third groups were exposed to 4-NP at a dose of 0.1 mg L^-1 of aquarium water and fed a basal diet only or supplemented with 2.5% NSS, respectively. The histological, histochemical, and ultrastructural features of the liver were subsequently evaluated as a damage biomarker of the hepatic tissue. Our results confirmed that 4-NP was a potent hepatotoxic agent, as 4-NP-intoxicated fish exhibited many lesions. Steatohepatitis, ballooning degeneration, sclerosing cholangitis, and coagulative necrosis of melanomacrophagecenters (MMCs) were observed. Hemosiderin, lipofuscin pigments, and proliferation of fibroblasts, kupffer cells, and telocytes were also demonstrated in the livers of 4-NP-intoxicated fish. In addition, decreased glycogen content and increased collagen deposition were observed in the hepatic tissue. Hepatocytes exhibited ultrastructural alterations in the chromatin, rough endoplasmic reticulum, smooth endoplasmic reticulum, mitochondria, lysosomes, and peroxisomes. Co-administration of 2.5% NSS to 4-NP-intoxicated fish significantly reduced these hepatotoxic effects. It nearly preserved the histological, histochemical, and ultrastructural integrity of hepatic tissue.

Nettle (Urtica dioica) Additive as a Growth Promoter and Immune Stimulator in Fish

Aquaculture will become an important food production sector for humans in the coming decades. However, disease outbreaks can be considered a significant obstacle to continually developing aquaculture. Plant powders and extracts are natural feed additives that, due to their bioactive compounds, including phenolic compounds, proteins, vitamins, and minerals, have antistress, antiviral, antibacterial, and antifungal effects on fish. One of these herbs is nettle (Urtica dioica), which has a long history of being used in traditional medicine. While it has been widely investigated in mammalian medicine, few studies have been done on aquaculture species. The positive effect of this herb on the growth performance, hematology, blood biochemistry, and immune system of fish species has been observed. When fish were exposed to pathogens, nettle-fed fish showed a higher survival rate and less stress than controls. Therefore, this literature review is aimed at reviewing the use of this herb in fish diets and its impacts on growth performance, hematology, blood biochemistry, liver enzymes, immune system stimulation, and challenges with pathogens.

The Beneficial Impacts of Essential Oils Application against Parasitic Infestation in Fish Farm

Aquaculture is a growing sector due to the high rising demand for fish, shrimp, oysters, and other products, which is partially conflicted by various infectious diseases. The infectious diseases affecting the production and inducing high mortalities cause substantial economic losses in this sector. Also, parasitic infections may induce severe mortality and morbidity in fish farms. Therefore, most farmers apply several kinds of antibiotics to control the problems induced by bacterial diseases and, to some extent, parasitic infections. The extensive usage of antibiotics to control or prevent pathogens may lead to the development of pathogenic resistant strains that might cause hazards to human health. Besides, there is a global trend toward reducing the application of antibiotics in aquaculture farms. Thus, there is a great effort to discover new natural and safe products with pharmaceutical properties, such as natural essential oils (EO). Essential oils are secondary metabolites of many plants (roots, flowers, seeds, leaves, fruits and peels) and their molecular structures provide a high antimicrobial and antiparasitic efficiency against pathogens. Consequently, it is essential to provide sufficient knowledge about the mode of action of EO against fish parasites and its future applications and directions in aquaculture.

Effect of Licorice (Glycyrrhiza glabra) Extract as an Immunostimulant on Serum and Skin Mucus Immune Parameters, Transcriptomic Responses of Immune-Related Gene, and Disease Resistance Against Yersinia ruckeri in Rainbow Trout (Oncorhynchus mykiss)

This study was designed to appraise the effect of licorice herbal supplement on the immune status of rainbow trout fingerlings. Accordingly, five diets were formulated with different levels of licorice extract (LE) including 0 (control), 0.5 g kg−1 (LE0.5), 1 g kg−1 (LE1), 2 g kg−1 (LE2), and 3 g kg−1 (LE3). The fingerlings (10.0 ± 0.1 g initial mean weight) received the diets in triplicates (30 fish in each replicate) for 56 days. The results showed that the white blood cells and their differential number (lymphocytes and monocytes) were remarkably increased by LE2 supplementation (P &lt; 0.05). The oral administration of LE2 significantly increased the levels of serum immunoglobulin (Ig), lysozyme activity, and complement components (C3 and C4) compared with others. Meanwhile, the serum bactericidal activity against Yersinia ruckeri in LE2 and LE3 treatments was significantly higher than others except for LE1 (P &lt; 0.05). In addition, serum alternative complement activity significantly improved in all treated groups except LE0.5 compared with the control group (P &lt; 0.05). In terms of skin mucosal immunity, the fish fed with LE2 and LE3 diets exhibited notably higher lysozyme activity, alkaline phosphatase activity, and Ig value than other groups (P &lt; 0.05). The highest skin mucus bactericidal activity against Y. ruckeri was obtained in LE2 treatment (P &lt; 0.05). In addition, dietary LE2 significantly increased the relative expression of immune-associated genes including tumor necrosis factor-α, interleukin-1β, interleukin-8, and IgM and the former treatments showed higher values than the control group. The cumulative mortality of fish against Y. ruckeri infection was notably reduced from 53.6% in the control group to 29.0% in LE3 treatment. Overall, the dietary administration of LE at 2 g kg−1 had the best effects on immunocompetence in rainbow trout.

Possible therapeutic effects of Nigella sativa and its thymoquinone on COVID-19

CONTEXT

COVID-19 is a novel coronavirus that causes a severe infection in the respiratory system. Nigella sativa L. (Ranunculaceae) is an annual flowering plant used traditionally as a natural food supplement and multipurpose medicinal agent.

OBJECTIVE

The possible beneficial effects of N. sativa, and its constituent, thymoquinone (TQ) on COVID-19 were reviewed.

METHODS

The key words including, COVID-19, N. sativa, thymoquinone, antiviral effects, anti-inflammatory and immunomodulatory effects in different databases such as Web of Science (ISI), PubMed, Scopus, and Google Scholar were searched from 1990 up to February 2021.

RESULTS

The current literature review showed that N. sativa and TQ reduced the level of pro-inflammatory mediators including, IL-2, IL-4, IL-6, and IL-12, while enhancing IFN-γ. Nigella sativa and TQ increased the serum levels of IgG1 and IgG2a, and improved pulmonary function tests in restrictive respiratory disorders.

DISCUSSION AND CONCLUSIONS

These preliminary data of molecular docking, animal, and clinical studies propose N. sativa and TQ might have beneficial effects on the treatment or control of COVID-19 due to antiviral, anti-inflammatory and immunomodulatory properties as well as bronchodilatory effects. The efficacy of N. sativa and TQ on infected patients with COVID-19 in randomize clinical trials will be suggested.

The effects of combined inclusion of Malvae sylvestris, Origanum vulgare, and Allium hirtifolium boiss for common carp (Cyprinus carpio) diet: Growth performance, antioxidant defense, and immunological parameters

The present study aimed to investigate the effects of a mixture of three medicinal plants extracts (COP: common mallow (Malvae sylvestris), oregano (Origanum vulgare), and Persian shallot (Allium hirtifolium boiss)) on growth, hematological indices, immunological parameters, liver antioxidant, and digestive enzyme activity of common carp (Cyprinus carpio). Accordingly, 540 common carp fingerlings were randomly allotted to 18 fiberglass tanks, including six treatments each in triplicate. Fish were fed with experimental diets supplemented with 0, 0.5, 1, 2, 3, and 5% of the herbal mixture. After 60 days, the effects on growth performance, antioxidant, and immunological parameters were evaluated. According to the results, the highest final weight was observed in the fish fed 2 and 3% of the herbal mixture. Also, the feed conversion ratio (FCR) showed a significant decrease in fish treated with the herbal mix, so that the lowest FCR was observed in the treatment 1%. Hematological examinations such as red blood cells (RBC), white blood cell (WBC), and hemoglobin showed significant changes between different parameters compared to the control group. The highest protein content was observed in the fish supplemented with 2, 3, and 5% herbs. Besides, in contrast to glucose, the cortisol level showed a significant decrease compared to the control group. The digestive enzymes (Amylase, Lipase, and Protease) were significantly higher in 2 and 3% treatments than in the control group. Also, a significant difference was found in Superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR) activity, and malondialdehyde (MDA) content between the experimental and control treatments. Examination of liver enzymes (and alanine aminotransaminase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP)) showed a significant difference in herbal mixture treatments with the control group, according to which the lowest amount of these enzymes was recorded in 2 and 3% herb supplemented fish. Herbal mix resulted in higher mucosal and intestinal immunity parameters, including total immunoglobulin (total Ig), lysozyme, alternative complement activities (ACH50), protease, and ALP. According to the results, supplementing the diet with a mixture of the COP can significantly improve growth parameters, stimulate the innate immune system, and improve antioxidant defenses and liver health of common carp.

A qualitative and quantitative comparison of Crocus sativus and Nigella sativa immunomodulatory effects

The present article reviews and compares the immunomodulatory activities of Crocus sativus (C. sativus) and Nigella sativa (N. sativa) and their main bioactive compounds. Immunomodulatory effects of these plants, especially with respect to Th1 and Th2 cytokines, are discussed based on relevant articles, books, and conference papers published in English until the end of April 2020, that were retrieved from Web of Science, PubMed, Scopus and Google Scholar databases. C. sativus and its constituents increase immunoglobulin (Ig-)G, interleukin 2 (IL)-2, interferon gamma (IFN-γ), and IFN-γ/IL-4 ratio, but decreased IgM, IL-10 and IL-4 secretion. N. sativa extract and thymoquinone reduce the levels of IL-2, -4, -10, and -12, while enhance IFN-γ and serum IgG1 and 2a. The reviewed articles indicate that C. sativus and N. sativa and their constituents could be potentially considered promising treatments for disorders associated with immune-dysregulation such as asthma and cancer.

Marinated Anchovies (Engraulis encrasicolus) Prepared with Flavored Olive Oils (Chétoui cv.): Anisakicidal Effect, Microbiological, and Sensory Evaluation

To meet the food demand of future generations, more sustainable food production is needed. Flavored olive oils (FOOs) have been proposed as natural additives to ensure food safety and quality through a more sustainable approach. The chemical composition and antioxidant potential of two different olive oils flavored, respectively, with cumin (Cm) and with a mixture of parsley, garlic, and lemon (Mix) were investigated. Cm-FOO and Mix-FOO were tested against Anisakis both in vitro and ex vivo through an exposure test of anchovy fillets experimentally parasitized with Anisakis larvae. Microbiological and sensory analysis were carried out on marinated anchovy fillets exposed to both FOOs to evaluate their effects on the shelf life and their sensory influence. The addition of herbs and spices did not affect the chemical composition of the olive oil (free acidity, UV absorbance, and fatty acid composition). Only Mix showed antioxidant activity, while Cm had no effect in this regard. Cm-FOO and Mix-FOO devitalized the Anisakis larvae both in vitro within 24 h and ex vivo after 8 and 10 days of exposure, respectively. The results of microbiological analyses showed that FOOs inhibited the growth of typical spoilage flora in the marinated anchovies without negatively affecting their sensory characteristics, as observed from the sensory analysis.

Nigella sativa (Black Seed) as a Natural Remedy against Viruses

The currently available antiviral agents are associated with serious adverse effects, coupled with the increasing rate of viral resistance to the existing antiviral drugs. Hence, the search for alternative natural remedies is gaining momentum across the globe. Nigella sativa Linnen, also called Black seed, is a medicinal plant that is gaining worldwide recognition and has been extensively investigated. The present work is aimed to review the existing literature on the antiviral efficacy of Nigella sativa extracts (oil & bioactive compounds). The findings reveal that numerous articles have been published on Nigella sativa and its beneficial effects against different kinds of diseases. However, the antiviral efficacy of Nigella sativa is yet to be given the proper research attention it deserves.

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.

Cytoprotective effect of Nigella sativa seed on 4-nonylphenol-induced renal damage in the African catfish (Clarias gariepinus)

4-Nonylphenol (4-NP) is a nephrotoxic substance that is highly prevalent in aquatic environments. Nigella sativa seed (NSS) has many biological activities and is widely used throughout the world as a medicinal product. Therefore, in the present study, we investigated the cytoprotective effect of NSS on 4-NP-induced renal damage in African catfish (Clarias gariepinus). Thirty fish were divided into five equal groups: an untreated control group and four groups that were challenged with 4-NP at a dose of 0.1 mg L^-1 of aquarium water and fed a basal diet supplemented with 0%, 1%, 2.5%, and 5% NSS, respectively, for 3 weeks. Histological, histochemical, and ultrastructural features of the kidney were then assessed as biomarkers for renal tissue damage. Our results confirmed that 4-NP was a potent cytotoxic agent for the kidney tissue and induced renal damage, with 4-NP-intoxicated fish showing necrosis in the epithelial cells of the renal corpuscles, renal proximal convoluted tubules, and intertubular hematopoietic tissue, as well as loss of or a decrease in microvilli, a decrease in mitochondria, and an increase in the lysosomes in the epithelial cells of the proximal convoluted tubules. The kidneys of 4-NP-intoxicated fish also showed increased numbers of Perls' Prussian blue-positive melanomacrophage centers and intraepithelial T-lymphocytes in the proximal convoluted tubules and plasma cells. The administration of NSS to 4-NP-challenged fish significantly minimized the cytotoxic effect of 4-NP, maintaining the normal kidney structure, with concentrations of 2.5% and 5% of feed being most effective for protecting the kidney against 4-NP-induced renal damage.

Dietary supplementation of lemon verbena (Aloysia citrodora) improved immunity, immune-related genes expression and antioxidant enzymes in rainbow trout (Oncorrhyncus mykiss)

The use of veterinary drugs for the treatments of fish diseases has often health and environmental side effects and thus alternative more sustainable strategies are needed. In this study we have explored the effect of dietary administration of lemon verbena (Aloysia citrodora) leaves powder on growth, immune parameters and antioxidant enzyme activity of rainbow trout (Oncorrhyncus myskiss). The results show that adding lemon verbena (LV) leaves powder (0.5, 1 and 2%), as feed supplement does not affect significantly rainbow trout growth, but increases the levels of some immune parameters. All enriched-diets induced an increase in the levels of lysozyme activity and total immunoglobulin in rainbow trout serum (P < 0.05), whilst 1 and 2% enriched-diets increased lysozyme and immunoglobulin in skin mucus. Expression of interleukin-1β (IL-1β) was enhanced in all fish supplemented with LV leaves powder (0.5, 1 and 2%) whilst only the diet with the highest dose (2%) induced a significantly higher expression of IL-8 and tumour necrosis factor (TNF-α). Fish fed with LV leaves powder at 1 and 2% had significantly lower expression of transforming growth factor (TGF-β, P < 0.05). Furthermore, all enriched-diets significantly increased the activity of super oxide dismutase (SOD, P < 0.05) and diets containing 1 and 2% of LV leaves powder also increased activity of glutathione-S-transferase (GST) and glutathione peroxidase (GPx). In conclusion, LV leaves powder administered as feed supplement at 2% enhances the expression of some immune-related genes (IL-1β, IL-8 and TNF- α), rises the levels of lysozyme and total immunoglobulin in serum and skin mucus and increases the activity of antioxidant enzymes (SOD, GST and GPx) in rainbow trout.

Extract of common mallow (Malvae sylvestris) enhances growth, immunity, and resistance of rainbow trout (Oncorhynchus mykiss) fingerlings against Yersinia ruckeri infection

The dietary effects of a native medicinal plant from Iran, common mallow (Malvae sylvestris), was evaluated on growth performance, innate immune parameters, mucosal immune parameters, and resistance of rainbow trout (Oncorhynchus mykiss) against Yersinia ruckeri. Therefore, 360 fish (initial weight 10.42 ± 0.09 g) were randomly distributed into 12 fiberglass tanks. Experimental diets supplemented with 0 (as control- C), 1% (M1), 3% (M2) and 5% (M3) levels of M. sylvestris flowers extract were fed to the fish based on 3% of body weight for 8 weeks. At the terminal sampling, growth performance, liver and digestive enzymes activities, blood and mucosal immune responses were determined. Results showed that M2 and M3 had greater final weight, weight gain, SGR, survival rate and lower FCR; higher levels of total protein, albumin, globulin, and lower cortisol levels in comparison to control; 5% extract also lowered cholesterol and glucose levels as well as Lactate Dehydrogenase (LDH) activity. We reported higher values of hematocrit, hemoglobin, Mean Corpuscular Hemoglobin (MCH), Mean Corpuscular Volume (MCV), White Blood Cell (WBC), Red Blood Cell (RBC) and lymphocytes for treated groups. Innate immune responses (Alternative complement activity (ACH50) in M2 and M3 group, total Immunoglobulin (Ig) and lysozyme in M3), mucosal immune parameters (ACH50, total Ig for M2 and M3 group and lysozyme in all treated groups) were enhanced. Activities of digestive enzymes (protease in all treated groups, amylase for 3 and 5%, while lipase only for 5%) and lower activity of liver ALT enzyme in individuals treated with highest dose was observed. Overall results indicated that the extract can positively affect growth performance and immune responses of rainbow trout.

Can dietary jujube (Ziziphus jujuba Mill.) fruit extract alter cutaneous mucosal immunity, immune related genes expression in skin and growth performance of common carp (Cyprinus carpio)?

The present study investigates the effect of dietary Ziziphus jujube fruit extract [ZJFE] on skin mucus non-specific immune parameters as well as mRNA levels of immune related gene in the skin of common carp fingerlings. An eight-week feeding trial was performed using different levels of dietary ZJFE (0, 0.25, 0.5 and 1%). At the end of the trial skin mucus immune parameters (total Ig, lysozyme and protease activity), cytokines genes (il1b, il8, il10 and tnf-alpha) expression in skin and growth performance were studied. The result showed highest and lowest skin mucus total Ig were observed in fish fed diet containing 0.5% ZJFE and control group, respectively (P < 0.05). There were no significant difference among treatments regarding skin mucus lysozyme activity (P >0.05). It should be noted that, feeding on 0.5 and 1% ZJFE significantly increased skin mucus protease activity (P <0.05). Likewise, gene expression studies in skin showed significant increase of il1b expression in fish fed 0.5% ZJFE compared other treatments (P <0.05). Also, il8 gene was noticeably up-regulated in 0.5 and 1% treatments compared to the control group (P <0.05). While there were no significant difference between 0.25% JFE treatment and control in case of relative il10 gene expression (P >0.05), feeding on diets containing 0.5% or 1% ZJFE significantly down-regulated il10 gene (P <0.05). Our study indicated that relative expression of tnf-alpha gene significantly increased in treated groups (P <0.05). Also, feeding on ZJFE supplemented diet improved growth performance parameters. Overall, this experiment demonstrated the potentially useful effects of ZJFE on skin mucosal immunity and performance of common carp fingerlings.

Muli bamboo (Melocanna baccifera) leaves ethanolic extract a non-toxic phyto-prophylactic against low pH stress and saprolegniasis in Labeo rohita fingerlings

Bamboo (Melocanna baccifera) plant plays a significant role in traditional Asian medicine and it can be used as an alternative to various chemo-therapeutics or prophylactic agents used in aquaculture. In the present study, the 1^st experiment was done for the preparation of extracts from bamboo leaves by using 90% alcohol as a solvent. In the 2^nd experiment, toxicity study was carried on Labeo rohita fingerlings (average length of 10.3 ± 1.5 cm and weight 18.5 ± 1.5 g) using BLAL (Bamboo Leaf Alcoholic) extract and it did not show any mortalities in fish even at the dose of 20 g kg^-1 body weight, which can be regarded as virtually non-toxic with minimal effect. The 3^rd experiment was conducted to find out the effect of BLAL extract based isocaloric and isonitrogenous feed (doses: control- 0.0%, diet T1-0.01%, diet T2-0.1%, diet T3-1% BLAL extract kg^-1 feed) on the haemato-immuno-biochemical parameters of L. rohita fingerlings (average length 15.7 ± 1.5 cm and weight 20.2 ± 1.5 g). Regular sampling was done (on 7^th, 15^th, 30^th and 60^th day of feeding) for different haematological, immunological and biochemical parameters. The study revealed that the best response occurred within 7 days of feeding with BLAL extract and long-term feeding have shown immunosuppressive condition in the fish. In the 4^th experiment, fish were exposed to multiple stressors like low pH stress, and Saprolegnia parastica infection after feeding with BLAL extract (0.1%) based feed for 7 days. The study showed that the BLAL extract can make fish resistant to single stress however, not able to reduce the fish mortality under multiple stresses (S. parastica infection under low pH). Thus, it can be concluded that the BLAL has the potentiality to be used as a non-toxic phyto-prophylactic which can induce non-specific immune response, reduces the low pH stress responses and increases the resistance against saprolegniasis under neutral pH condition in rohu fingerlings.

Changes in growth, blood immune parameters and expression of immune related genes in rainbow trout (Oncorhynchus mykiss) in response to diet supplemented with Ducrosia anethifolia essential oil

An 8- week feeding trial was conducted to investigate the effects of Ducrosia anethifolia essential oil on growth, blood immune parameters and immune related genes expression in juvenile rainbow trout (Oncorhynchus mykiss). Fish were allocated into 4 groups and fed on diet containing different levels of essential oil (0, 0.001, 0.01 and 0.1%) to apparent satiation in 30 min 3 times daily. Growth and immunological parameters were measured every ten days and tissue samples were taken from kidney and spleen on days 10, 30 and 50 to study the expression of IL-1β and TNF-α. The changes of measured parameters in different treatments and over sampling time series were statistically analysis based on repeated measurement method (P < 0.05). Results showed that growth did not affected by essential oil at different treatments. The highest level of hematocrit was observed in 0.001 treatment. The mean of RBC showed no significant differences among treatments. The mean of WBC in 0.01 and 0.1 groups were higher than those in 0.001 and control groups. Total protein, albumin and globulin and serum bactericidal activity showed no significant difference in different treatments. Neither treatments nor sampling times affected serum lysozyme activity. The highest mean of respiratory burst activity was observed in 0.01 group. The highest expression of both IL-1β and TNF-α genes in kidney was observed at 0.001 dose on day 30, while in spleen, the highest expression of IL-1β and TNF-α was obtained on day 30 at doses 0.1 and 0.01%, respectively. In conclusion the results of this study showed that feeding with lower and medium level of D. anethifolia for 30 days led to immunostimulatory effects in juvenile rainbow trout.

Immune responses to methanolic extract of black cumin (Nigella sativa) in rainbow trout (Oncorhynchus mykiss)

The immune stimulating effects of the methanolic extract of black cumin (Nigella sativa) in rainbow trout (Oncorhynchus mykiss) was evaluated. Variable concentrations of black cumin methanolic extract [0 (Control), 0.1 and 0.5 g kg^-1 of feed] were individually added to the basal diet and rainbow trout was fed for 30 days to assess the innate immune responses and growth performance. Feed conversion ratio significantly decreased in the group fed with 0.5 g kg^-1 black cumin extract. Respiratory burst activity was observed to be the highest in the 0.5 g kg^-1 black cumin extract fed group. Lysozyme and myeloperoxidase activities were significantly increased in fish of experimental groups compared to control (P < 0.05). TGF-β gene expression increased in black cumin 0.5 g kg^-1 treated group. IL-1β and TGF-β gene expressions decreased in black cumin 0.1 g kg^-1 administered group. Expression of IL-12 gene diminished in both the experimental groups. There was no significant difference in survival rates between black cumin extract treated fish groups and control (P > 0.05) after challenged with Aeromonas hydrophila. The results indicate that the methanolic extract of black cumin is a stimulator of some innate humoral immune responses, but it is ineffective for cytokine-related gene trancriptions in rainbow trout.

Hemato - Immunological and biochemical parameters, skin antibacterial activity, and survival in rainbow trout (Oncorhynchus mykiss) following the diet supplemented with Mentha piperita against Yersinia ruckeri

This study was aimed to assess the potential effects of Mentha piperita on the hemato - immunological and biochemical parameters, skin antibacterial activity and protection against Yersinia ruckeri infection in rainbow trout Oncorhynchus mykiss. Fish were divided into 4 groups before being fed diets supplemented with 0, 1, 2 and 3% of Mentha piperita (MP) plant extract for 8 weeks. Dose-dependent increases immune (both in skin mucus and blood serum) and hematological parameters (number of red and white cells, hematocrit and hemoglobin contents), as well as in respiratory burst activity, total protein, albumin, and neutrophil levels in fish fed supplemented diets compared to the control fish. Furthermore, dietary MP plant extract supplements have no significant effect on blood biochemical parameters and enzymatic activities of liver determined in serum of rainbow trout. After 8 weeks the cessation of feeding with MP plant extract, survival rates of 54.4%, 63.6% and 75.2% were recorded in groups which received 1, 2 and 3% of MP plant extract of feed, respectively, compared to 34.6% survivals in the control. This study underlying several positive effects of dietary administration of MP plant extract to farmed fish.

Protective efficacy of Nigella sativa seeds and oil against columnaris disease in fishes

Columnaris disease, caused by the bacterium Flavobacterium columnare, is currently the most frequently reported bacterial disease affecting farm-raised channel catfish in the USA. Common treatments against the disease include the use of medicated feed that has led to emergent antibiotic resistant strains of F. columnare. Nigella sativa (Black cumin) is a medicinal herb commonly used by many cultures as a natural remedy for numerous disorders. Recently, we have discovered the antibacterial activity of N. sativa and its oil extract against F. columnare. In this study, we showed N. sativa oil (NSO) strongly inhibited the growth of all of the strains of F. columnare tested and yielded significantly larger zones of inhibition than those produced by oxytetracyclin. We tested the protective effect against columnaris disease in vivo by incorporating NSO (5%) or N. sativa seeds (NSS) (5%) into fish feeds. Fishes (Ictalurus punctatus and Danio rerio) fed amended diets displayed significantly lower mortality than those fed control diets. Per cent mortalities in control groups ranged from 77% to 44% and from 70% to 18% in zebrafish and channel catfish, respectively. A dose study using different NSS concentrations showed that 5% NSS offered the most protection against columnaris disease in channel catfish.

Dietary supplementation of Zeolite on growth performance, immunological role, and disease resistance in Channa striatus against Aphanomyces invadans

Epizootic Ulcerative Syndrome (EUS) caused by Aphanomyces invadans which is a primary fungal parasitic pathogen, inflicts serious economic loss in tropical freshwater fish including snakehead murrel, Channa striatus. In the present study with an aim to circumvent the adverse effects of the traditional measures in graded levels (2%, 4%, and 6%) of Zeolite enriched diet on growth performance, hematology, immunological response, and disease resistance in C. striatus against A. invadans is reported. The final weight (FW), specific growth rate (SGR), feed conversion ratio (FCR), protein efficiency ratio (PER), and average daily gain (ADG) were significantly high in infected fish fed with 4% or 6% Zeolite incorporated diets on 4th week. The maximum survival rates (SR) of 96% and 98% were observed when fed with 2% or 4% diets on 4th week. Similarly, the white blood cell (WBC), red blood cell (RBC), hematocrit (Hct), mean corpuscular volume (MCV), and mean corpuscular haemoglobin concentration (MCHC) were significantly high when fed with any Zeolite enriched diet. However, the haemoglobin (Hb) and mean corpuscular haemoglobin (MCH) were significantly high with 4% and 6% Zeolite diets. The total protein and globulin were significantly high with 4% and 6% diets; the albumin, glucose, cholesterol, and triglyceride were significantly elevated with any enriched diet. The 4% and 6% Zeolite diets significantly enhanced the phagocytic activity on 2nd week but the 2% diet could increase it on 4th week. The respiratory burst (RB) activity, complement activity, and lymphocyte proliferation level were significantly enhanced with 4% and 6% Zeolite diets on weeks 1 and 2 while with 2% diet on 4th week. All enriched diets significantly increased the lysozyme activity during the experimental period. Superoxide anion (SOA) production significantly enhanced with 6% diet on weeks 1 and 2 whereas with 2% diet on week 4. Lower cumulative mortality of 10% and 15% was found with 4% and 6% Zeolite diets whereas a higher mortality (20%) was observed with 2% diet. The present study suggests that dietary supplementation with 4% or 6% Zeolite significantly increase growth performance, hemato-biochemical changes, immunological response, and disease resistance in C. striatus against A. invadans.

Dietary Aloe vera supplementation on growth performance, some haemato-biochemical parameters and disease resistance against Streptococcus iniae in tilapia (GIFT)

This study investigated effects of dietary Aloe vera on growth performance, some haemato-biochemical parameters and disease resistance against Streptococcus iniae in tilapia (GIFT). Five groups were designed including a basal diet (control) and 100% A. vera powder incorporated in fish feed at 0.5% 1%, 2%, and 4%/kg feed, which were administered for 8 weeks. Fish fed 0.5%, 1%, and 2% A. vera supplemented diet significantly improved (p < 0.05) weight gain, absolute growth rate and specific growth rate. Feed intake significantly increased in fish fed with A. vera diet at 1% and 2%/kg feed. Feed efficiency ratio, feed conversion ratio, and hepatosomatic index were significantly enhanced in 4% A. vera supplemented fish over unsupplemented ones (p < 0.05). Several haemato-biochemical indices were examined before and after fish were challenged with S. iniae pathogen containing 7.7 × 10(6) CFU cells mL(-1). A. vera supplemented fish showed a significant increase (p < 0.05) in red blood cells, hematocrits (Hb), hemoglobin (Hb), white blood cells (WBC), neutrophils, monocytes, eosinophils, serum total protein, glucose and cortisol after challenge when compared to unsupplemented ones. Meanwhile, 4% A. vera supplemented fish showed a decrease (p < 0.05) in RBC, Hb, Ht, WBC, and mean corpuscular hemoglobin (MCH) after challenge compared to unsupplemented ones and other supplemented ones. In addition, lower mean corpuscular volume values (MCV) (p < 0.05) were observed in fish fed with A. vera diet at 2% and 4% A. vera/kg feed than those fed unsupplemented diet. Unchallenged fish fed 0.5%, 1%, and 2% A. vera showed significantly higher values (p < 0.05) of mean corpuscular hemoglobin concentration (MCHC) than those fed unsupplemented diet and 4% A. vera supplemented diet. There was a significant increase (p < 0.05) in the neutrophil to lymphocyte ratio (N/L) within experimental groups after challenge; N/L ratio in A. vera unsupplemented fish and those supplemented with A. vera diet at 1%/kg feed increased significantly (p < 0.05) throughout challenge period; while those fed 4% A. vera supplemented diet maintained higher values at all experimental stages among groups. There was a significant correlation (p < 0.05, r = 0.53) between N/L ratio and glucose concentration, 96 h after challenge. Aloe had no significant effect (p > 0.05) on the survival of the fish when compared to the control; no mortality was recorded in challenge trial. Overall, our results indicated that dietary aloe supplementation could improve growth, feed utilization, and haemato-biochemical parameters of cultured tilapia.