Activation of rainbow trout, Oncorhynchus mykiss, phagocytic cells by administration of bovine lactoferrin

Effects of extended dietary supplementation with Santalum album essential oil on hemato-biochemical changes, innate immune response, antioxidant status, and expression of related gene in Nile tilapia (Oreochromis niloticus)

The effects of long-term dietary supplementation with sandalwood (Santalum album L.) essential oil (SEO) was investigated on hemato-biochemical biomarkers, immune status, antioxidant capacity, and resistance against Staphylococcus aureus in Nile tilapia (Oreochromis niloticus). Five groups (with four replicates) of O. niloticus (12.60 ± 0.20 g) were fed diets supplemented with SEO at doses of 0, 0.5, 1.0, 2.0, and 4.0 mL/kg diet for 60 days. Results indicated a substantial increase in blood protein levels and lower serum cholesterol, cortisol, glucose, urea, creatinine levels and, transaminase activities of fish fed a 2.0-mL SEO/kg diet. Serum lysozyme activity, nitric oxide, complement-3 levels, and phagocytic activity were significantly improved in O. niloticus after 60 days of feeding SEO-supplemented diets. Dietary SEO at level of 2.0-mL SEO/kg diet increased the activities of SOD, CAT, and GPx, and decreased MDA levels in liver homogenate. In addition, dietary 2.0-mL SEO/kg diet significantly upregulated antioxidant genes expression (CAT, SOD, GPx, GST, and GSR) with downregulation of apoptotic genes (HSP70, TLR2, caspase-3, and PCNA) in the liver. Furthermore, SEO-enriched diets significantly down-regulated pro-inflammatory (TNF-α, IL-1β, and IL-8) and up-regulated anti-inflammatory cytokine genes (TFG-β and IL-10) in the spleen. Moreover, SEO fortification increased the relative percentage of survival against S. aureus challenge and regulated immune-antioxidant genes in the spleen after the challenge. Overall, the results revealed that long-term using SEO might strengthen the physiological performance, hepatic oxidant/antioxidant balance, innate immune response, and resistance of O. niloticus against bacterial infections.

Effects of dietary antimicrobial peptides on intestinal morphology, antioxidant status, immune responses, microbiota and pathogen disease resistance in grass carp Ctenopharyngodon idellus

This study aims to highlight the effects (8 weeks) of dietary antimicrobial peptides (AMPs, a compound of 6 kDa and 5 kDa from intestine) on intestinal morphological functions and health status in grass carp (Ctenopharyngodon idellus). Fish were supplemented with various gradient concentrations of AMPs, including M0 (0 mg/kg), M1 (100 mg/kg), M2 (200 mg/kg), M3 (400 mg/kg), M4 (800 mg/kg) and M5 (1600 mg/kg). Our results showed that amylase, lipase, chymotrypsin enzymatic levels, and total antioxidant capacity (T-AOC) were significantly increased (p < 0.05), while malondialdehyde (MDA) content was significantly decreased in the intestines of the AMP treated groups compared to the M0. Histological analysis revealed villus height and crypt depth of foregut and midgut in the M4 group were significantly different (p < 0.05) compared to the M0. In the M3 group, the gene expression levels of IL-1β were significantly up-regulated, while levels of IL10 and TGF-β were significantly down-regulated than other treated and control groups. The abundance of Firmicutes was significantly increased (p < 0.05), while the Planctomycetes abundance was decreased at phylum level in M1-M5 groups. Subsequent to the AMP treatment, fish were injected with Aeromonas. hydrophila to assess disease resistant potential. In A. hydrophila injected M3-group, the gene expressions of IL-1β, IL8, and TNF-α were significantly down-regulated while that of TGF-β was significantly up-regulated, and IL10 showed no significant difference compared to the control. Further, AMPs also increased the abundance of the Acidobacteria, Proteobacteria, and Patescibacteria, and decreased the abundance of the Fusobacteria and Firmicutes. Therefore, dietary AMPs (400-800 mg/kg) boosted intestinal health by promoting intestinal morphology, digestive and antioxidant capacities, immunity, and intestinal microbiota in C. idellus.

Effect of cassic acid on immunity and immune-reproductive genes transcription in Clarias gariepinus against Edwardsiella tarda

The present study was investigated the dietary administration of cassic acid (CA) on growth, innate immunity, transcription profiles of estrogen and follicle-stimulating hormones as well as lysozyme enzyme determined in Clarias gariepinus against Edwardsiella tarda. The weight gain (WG), protein efficacy ratio (PER), and feed conversion ratio (FCR) were significantly improved in infected fish fed dietary administration with CA at 5 and 10 mg kg^-1 diets. The survival is higher (96.7% and 98.3%) in the infected groups fed at 5 and 10 mg kg^-1 CA diets. The red (RBC) and white (WBC) blood cells, hemoglobin (Hb), and packed cell volume (PCV) was found significantly high in the infected fish feeding at 5 and 10 mg kg^-1 CA diets. Total protein and albumin were significantly increased with 5 and 10 mg kg^-1 CA diets among weeks 1-4 while the globulin and albumin: globulin ratio increased of these diet only after week 2. The phagocytic and respiratory burst activities were enhanced statistically the infected fish fed at 10 mg kg^-1 CA diet group whereas the production of superoxide anion (SOA) and nitric oxide (NO) were significantly increased at 5 and 10 mg kg^-1 CA diets. The lymphocyte proliferation and myeloperoxidase (MPO) activity were significantly high the infected fish when fed at 5 and 10 mg kg^-1 CA diets after 2nd week whereas the alternate complement activity (ACP), generation of reactive oxygen species (ROS), and lysozyme activity (Lyz) were observed at 5 and 10 mg kg^-1 CA diets among weeks 1-4. The accumulative mortality was 10% in infected fish fed at 1 and 5 mg kg^-1 CA diets whereas 15% mortality found with 10 mg kg^-1 CA diet. The highest levels of estrogen receptor alpha (ERα) mRNA expression found in gonad while the highest levels of follicle stimulating hormone-beta subunit (FSH-β) mRNA expression found in testis of the infected fish given at 5 and 10 mg kg^-1 CA diets. The up-regulation of chick-type lysozyme (c-Lyz) mRNA was observed at 5 and 10 mg kg^-1 CA diets after 2nd week while goose-type lysozyme (g-Lyz) mRNA was up-regulation amongst weeks 1-4 of these diets. The present study suggested that E. tarda challenged fish after feeding with 5 and 10 mg kg^-1 CA diets did not affect growth and hemato-biochemical parameter, but it enhanced nonspecific immune system and improving ERα, FSH-β, c-Lyz, and g-Lyz mRNA expression in C. gariepinus against E. tarda.

RETRACTED: Residual papaya promoting the growth performance, antioxidant, nonspecific immunity of juvenile Tilapia mossambica

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of Editors-in-Chief and first Author. The article duplicates significant parts of a paper that had already appeared in Fish & Shellfish Immunology, Volume 93 (2019) 726-731, https://doi.org/10.1016/j.fsi.2019.06.052. One of the conditions of submission of a paper for publication is that authors declare explicitly that the paper has not been previously published and is not under consideration for publication elsewhere. As such this article represents a misuse of the scientific publishing system. The scientific community takes a very strong view on this matter and apologies are offered to readers of the journal that this was not detected during the submission process. The article was published without the knowledge of the co-authors.

Metabolic and immune responses of Chinook salmon (Oncorhynchus tshawytscha) smolts to a short-term poly (I:C) challenge

Polyinosinic:polycytidylic acid [poly (I:C)] was administered in vivo to Chinook salmon (Oncorhynchus tshawytscha) post-smolts to determine the immune responses on haematological and cellular functional parameters, including spleen (SP), head kidney (HK) and red blood cell (RBC) cytokine expression, as well as serum metabolomics. Poly (I:C) in vivo (24 h exposure) did not affect fish haematological parameters, leucocyte phagocytic activity and phagocytic index, reactive oxygen species and nitric oxide production. Gas chromatography-mass spectrometry-based metabolomics revealed that poly (I:C) significantly altered the serum biochemistry profile of 25 metabolites. Metabolites involved in the branched-chain amino acid/glutathione and transsulphuration pathways and phospholipid metabolism accumulated in poly (I:C)-treated fish, whereas those involved in the glycolytic and energy metabolism pathways were downregulated. At cytokine transcript level, poly (I:C) induced a significant upregulation of antiviral ifnγ in HK and Mx1 protein in HK, SP and RBCs. This study provides evidence for poly (I:C)-induced, immune-related biomarkers at metabolic and molecular levels in farmed O. tshawytscha in vivo. These findings provide insights into short-term effects of poly (I:C) at haematological, innate and adaptive immunity and metabolic levels, setting the stage for future studies.

The regulation of the disease resistance, mTOR and NF-kB signaling pathway of Aristichthys nobilis using Rhodopseudomonas wastewater treatment

The employment of traditional feed and medicament in freshwater aquaculture causes the frequent occurrence of environmental pollution and disease. Effluent collected after Rhodopseudomonas-mediated wastewater treatment could be re-utilized as microbial feeds, and aquaculture water to culture Aristichthys nobilis. Therefore, a novel integrated system of wastewater treatment using effluent containing Rhodopseudomonas that improves yield, increases disease resistance, and enhances the quality of aquaculture water for Aristichthys nobilis culture was proposed and investigated. Aristichthys nobilis can grow well in effluent containing Rhodopseudomonas (ER). The survival rate, yield, and whole body composition of the ER group were all increased compared to the control group (CK). The biochemical (B vitamin) and other substances in the effluent of Rhodopseudomonas enhanced the activity of AKP, ACP, phagocytic, SOD, and CAT by upregulating the expression of AKP, ACP, SOD, and CAT genes. Moreover, Rhodopseudomonas and biochemical substances improved mTOR and NF-kB signaling pathway. Furthermore, Rhodopseudomonas inhibited Aeromonas hydrophila that increases resistance against fish disease. Meanwhile, Rhodopseudomonas in the effluent also improved the aquaculture water quality. This technology would save the aquaculture water, reduce water pollution and wastewater discharge, and increase the output and disease resistance of Aristichthys nobilis, simultaneously.

RETRACTED: Residual pomegranate affecting the nonspecific immunity of juvenile Darkbarbel catfish

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of Editors-in-Chief and first Author. The article duplicates significant parts of a paper that had already appeared in Fish & Shellfish Immunology, Volume 93 (2019) 726-731, https://doi.org/10.1016/j.fsi.2019.06.052. One of the conditions of submission of a paper for publication is that authors declare explicitly that the paper has not been previously published and is not under consideration for publication elsewhere. As such this article represents a misuse of the scientific publishing system. The scientific community takes a very strong view on this matter and apologies are offered to readers of the journal that this was not detected during the submission process. The first author informed the journal that the article was published without the knowledge of the co-authors.

Advances in salmonid fish immunology: A review of methods and techniques for lymphoid tissue and peripheral blood leucocyte isolation and application

Evaluating studies over the past almost 40 years, this review outlines the current knowledge and research gaps in the use of isolated leucocytes in salmonid immunology understanding. This contribution focuses on the techniques used to isolate salmonid immune cells and popular immunological assays. The paper also analyses the use of leucocytes to demonstrate immunomodulation following dietary manipulation, exposure to physical and chemical stressors, effects of pathogens and parasites, vaccine design and application strategies assessment. We also present findings on development of fish immune cell lines and their potential uses in aquaculture immunology. The review recovered 114 studies, where discontinuous density gradient centrifugation (DDGC) with Percoll density gradient was the most popular leucocyte isolation method. Fish head kidney (HK) and peripheral blood (PB) were the main sources of leucocytes, from rainbow trout (Oncorhynchus mykiss) and Atlantic salmon (Salmo salar). Phagocytosis and respiratory burst were the most popular immunological assays. Studies used isolated leucocytes to demonstrate that dietary manipulations enhance fish immunity, while chemical and physical stressors suppress immunity. In addition, parasites, and microbial pathogens depress fish innate immunity and induce pro-inflammatory cytokine gene transcripts production, while vaccines enhance immunity. This review found 10 developed salmonid cell lines, mainly from S. salar and O. mykiss HK tissue, which require fish euthanisation to isolate. In the face of high costs involved with density gradient reagents, the application of hypotonic lysis in conjunction with mico-volume blood methods can potentially reduce research costs, time, and using nonlethal and ethically flexible approaches. Since the targeted literature review for this study retrieved no metabolomics study of leucocytes, indicates that this approach, together with traditional technics and novel flow cytometry could help open new opportunities for in vitro studies in aquaculture immunology and vaccinology.

RETRACTED: Regulation of the disease resistance and mTOR and NF-kB signaling pathway of Tilapia mossambica by Rhodopseudomonas capsulatus wastewater treatment

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of Editors-in-Chief and first Author. The article duplicates significant parts of a paper that had already appeared in Fish & Shellfish Immunology, Volume 93 (2019) 726-731, https://doi.org/10.1016/j.fsi.2019.06.052. One of the conditions of submission of a paper for publication is that authors declare explicitly that the paper has not been previously published and is not under consideration for publication elsewhere. As such this article represents a misuse of the scientific publishing system. The scientific community takes a very strong view on this matter and apologies are offered to readers of the journal that this was not detected during the submission process. The first author informed the journal that the article was published without the knowledge of the co-authors.

RETRACTED: Effluent containing Rubrivivax gelatinosus promoting the yield, digestion system, disease resistance, mTOR and NF-kB signaling pathway, intestinal microbiota and aquaculture water quality of crucian carp

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of Editors-in-Chief and first Author. The article duplicates significant parts of a paper that had already appeared in Fish & Shellfish Immunology, Volume 93 (2019) 726-731, https://doi.org/10.1016/j.fsi.2019.06.052. One of the conditions of submission of a paper for publication is that authors declare explicitly that the paper has not been previously published and is not under consideration for publication elsewhere. As such this article represents a misuse of the scientific publishing system. The scientific community takes a very strong view on this matter and apologies are offered to readers of the journal that this was not detected during the submission process. The first author informed the journal that the article was published without the knowledge of the co-authors.

Effects of dietary supplementation of bovine lactoferrin on antioxidant status, immune response and disease resistance of yellowfin sea bream (Acanthopagrus latus) against Vibrio harveyi

This study investigated the effect of the dietary supplementation of bovine lactoferrin (LF) on growth performance, hematological and immunological parameters, antioxidant enzymes activity and disease resistance against Vibrio harveyi in yellowfin sea bream (Acanthopagrus latus) fingerling. The fish with initial body weight 10 ± 0.3 g were randomly distributed at 10 fish per each 250 L fiberglass tank, and fed with four experimental diets (a control basal diet and three supplemented diets with 400, 800 and 1200 mg LF kg^-1 diet) for 8 weeks. The obtained results showed that fish fed with LF supplemented diets had significantly higher final body weight as compared to control diet (P < 0.05). There were no significant differences between LF-treatments and the control group in white blood cell counts, red blood cell counts, hemoglobin and hematocrit. Total protein and complement activity (ACH50) in the serum of yellowfin sea bream were enhanced with increasing the dietary LF supplementation level (P < 0.05). The mucus lysozyme activity in fish fed on 800 and 1200 mg LF kg^-1 was significantly higher than those fed on 400 mg LF kg^-1 and control fish (P < 0.05). None of the antioxidant enzymes (catalase, glutathione reductase, glutathione S-transferase) was affected by LF supplementation (P > 0.05). Fish fed with dietary LF had a significantly higher survival rate than those fed with the control diet after challenge with Vibrio harveyi (P < 0.05). These results revealed that diet supplementation in A. latus especially with 1200 mg LF kg^-1 improve fish growth performance and immune parameters, as well as survival rate against Vibrio harveyi.

Feasibility of cultivation of Spinibarbus sinensis with coconut oil and its effect on disease resistance (nonspecific immunity, antioxidation and mTOR and NF-kB signaling pathways)

Application of traditional bait in aquaculture caused environment pollution and disease frequent occurrence. Residual coconut could be re-utilized to culture Spinibarbus sinensis as dietary supplement. Therefore, a novel integrated system of the improvement of yield, antioxidant and nonspecific immunity of Spinibarbus sinensis by dietary residual coconut was proposed and investigated. Spinibarbus sinensis could grow well in all supplement residual coconut groups. Survival rate, yield, whole fish body composition under 15-45% groups were increased compared with control group (CK). Bioactive substances (polyphenols and vitamin) in residual coconut enhanced AKP, ACP, phagocytic, SOD, CAT activities through up-regulating AKP, ACP, SOD, CAT genes expression levels. Theoretical analysis showed bioactive substances regulated these genes expressions and enzyme activities as stimulus signal, component, active center. Moreover, residual coconut improved mTOR and NF-kB signaling pathway. Furthermore, residual coconut inhibited Aeromonas hydrophila that increased resistance to diseases. This technology completed the solid waste recovery and the Spinibarbus sinensis culture simultaneously.

Physiological and immune response of juvenile rainbow trout to dietary bovine lactoferrin

Lactoferrin, a large multifunctional glycoprotein, is involved in many physiological functions but its immunomodulatory pathways are not well characterized in fish. The objective of the present study was to investigate the temporal effect of dietary bovine lactoferrin (BLf) at low (0.1%) and high (1%) on immunological organs of rainbow trout juveniles. BLf diets did not affect specific growth rate, haematocrit, splenic index, spleen respiratory burst activity as well as humoral (mIgM) and neutrophils (MPO) gene expressions after short term - 35 days (D35) and long term nutrient test - 51 days (D51) of feeding. Both low and high BLf doses induced enhanced level of plasma alternative complement activity, plasma total immunoglobulin on D35 and D51, lymphocyte plus thrombocyte cell proportion on D35 and monocyte cell proportion in total blood leukocyte cells on D51. On D51 but not on D35, BLf diets upregulated the expression of inflammatory genes in kidney for il-1 at the low BLf dose, il-8 at both BLf doses and il-6 at the high BLf dose in spleen, and il-10 at both BLf doses in kidney. Moreover, the expression of T helper (cd4-2α; cd4-2β) genes was significantly upregulated only on D51 by both BLf doses in both spleen and kidney tissues. On D51, controls and BLf treated fish were intraperitoneally injected with A. salmonicida achromogenes. The expression of 13 immune genes was evaluated at 44 h post-injection (D54). The expression of lysozyme gene was upregulated by both BLf doses after bacterial infection both in spleen and kidney. The expression of mcsfrα (spleen) and tgf-β1 (kidney) was also modulated by both BLf doses. Low and high BLf doses enhanced disease resistance of rainbow trout juveniles with the cumulative survival rate of 36% and 38% respectively while those of the control was 19% after 14 days challenged with bacteria. The results indicate that BLf diets activated the humoral immunity, associated to blood leukocyte cells of rainbow trout after short term BLf administration, and the long term BLf administration was necessary for sensitizing other lymphoid organs such as in spleen and kidney. Only after long term test, BLf diets induced significantly higher levels of innate and adaptive immune gene expressions than those of the control. Dietary BLf activated more markedly the expression of innate immune genes than the adaptive ones; this upregulation of some immune genes could explain the high disease resistance observed in rainbow trout juveniles fed BLf.

Jerusalem artichoke enriched diet on growth performance, immuno-hematological changes and disease resistance against Aeromonas hydrophila in Asian seabass (Lates calcarifer)

A 45 days feeding trial was conducted to study the effect of Jerusalem artichoke (JA) on growth performance, body composition, biochemical, immuno-hematological parameters and disease resistance in Asian seabass (Lates calcarifer) fingerlings against Aeromonas hydrophila. JA was supplemented at three different levels viz., control 0, 5, 10, and 20 g kg^-1 in the commercial diet (403 g kg^-1protein and 89 g kg ^-1lipid) in L. calcarifer. The results showed that there were no significant (P > 0.05) differences in various growth parameters, while the whole body composition showed significant differences (P < 0.05) between control and treatment groups. Hematological parameters showed that red blood cells (RBC), white blood cells (WBC), hemoglobin (Hb), pack cell volume (PCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC) were not significantly (P > 0.05) affected by dietary supplementation of JA at different concentration. However, the mean corpuscular volume (MCV) was significantly (P < 0.05) higher in the fish fed with 20 g kg^-1 JA supplemented diet. Biochemical parameters revealed that glucose, urea, cholesterol, and triglyceride showed significant (P < 0.05) differences between control and treatments groups. Interestingly, 20 g kg^-1 JA supplemented diet significantly modulates the innate immune response and disease resistance against Aeromonas hydrophila compared with control and other treatment groups. The results of the study revealed that 20 g kg^-1 JA supplementation has a beneficial effect in the biochemical, immunological and disease resistance in L. calcarifer juveniles.

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.

Effect of dietary astaxanthin against Aeromonas hydrophila infection in common carp, Cyprinus carpio

The effect of astaxanthin at 0, 25, 50, and 100 mg kg(-1) incorporated in basal feed on immune response and disease resistance in Cyprinus carpio against Aeromonas hydrophila was investigated. When fed with 25 mg kg(-1) diet, the cumulative mortality was 35% whereas it was 10% and 20% with 50 and 100 mg kg(-1) diets. With all enriched diets the growth rate increased significantly from week 1 to 4 when compared with control. However, the specific growth rate (SGR), feed conversion ratio (FCR), and protein efficiency ratio (PER) did not vary significantly from that of the control except with 50 mg kg(-1) diet. When fed with 50 and 100 mg kg(-1) diets the red blood cells, white blood cells, hemoglobin, and hematocrit values significantly increased. However, the serum total protein, albumin, and globulin contents significantly increased only when fed with 50 and 100 mg kg(-1) diets. The phagocytic ratio also significantly raised with 50 and 100 mg kg(-1) diets on week 2 and 4 whereas the phagocytic index significantly increased with all groups only on fourth week. The respiratory burst activity significantly increased in 25 mg kg(-1) diet group on first week whereas in 50 and 100 mg kg(-1) diet groups the activity increased on weeks 2 and 4; a similar trend was observed in the anti-protease activity only on weeks 2 and 4. The serum lysozyme activity and bactericidal activity registered a significant increase with all enriched diets. This study suggests that supplementation of astaxanthin at 50 and 100 mg kg(-1) with the basal diet significantly promotes the growth restores hematology and modulates the immune system in C. carpio against A. hydrophila.

Dietary fucoidan enhance the non-specific immune response and disease resistance in African catfish, Clarias gariepinus, immunosuppressed by cadmium chloride

Fucoidan is sulfated polysaccharide extracted from seaweed brown algae. This study was designed to evaluate the immunomodulatory effects and disease resistance of dietary fucoidan on catfish, Clarias gariepinus, immunosuppressed by cadmium. Three hundred and sixty African catfish, C. gariepinus, was allocated into six equal groups. The first group served as a control. Groups (F1 and F2) were fed on fucoidan supplemented ration at concentrations of 4 and 6g/kg diet respectively for 21 days. Groups (Cd, CdF1 and CdF2) were subjected throughout the experiment to a sub-lethal concentration of 5ppm cadmium chloride solution and groups (CdF1 and CdF2) were fed on a ration supplemented with fucoidan. Macrophages oxidative burst, phagocytic activity percentages and lymphocytes transformation index were a significant increase in the fucoidan-treated groups (F1 and F2), while serum lysozyme, nitric oxide and bactericidal activity were enhanced only in group (F2) when compared with controls. These parameters as well as absolute lymphocyte count and survival rate were significantly increased in group (CdF2) when compared with cadmium chloride immunosuppressed group (Cd). It could be concluded that the fucoidan can be used as immunostimulant for the farmed African catfish, C. gariepinus as it can improve its resistance to immunosuppressive stressful conditions.

Immune response and disease resistance of carotenoids supplementation diet in Cyprinus carpio against Aeromonas hydrophila

The effect of carotenoid-supplementation diet on immune response and disease resistance in common carp, Cyprinus carpio against Aeromonas hydrophila at weeks 1, 2, and 4 is reported. The cumulative mortality was 10% when fish were fed with 50 or 100 mg kg(-1) supplementation diets while the un-supplementation diet treated group suffered 90% mortality against the pathogen. The phagocytic activity and complement activity significantly increased with 50 and 100 mg kg(-1) diet groups from weeks 2 and 4 but not in other groups. The reactive oxygen species (ROS) production was significantly enhanced with 50 and 100 mg kg(-1) diets from weeks 1 to 4 while the production of reactive nitrogen species (RNS) enhanced on weeks 2 and 4. The lysozyme activity significantly increased when fed with 50 and 100 mg kg(-1) diets on weeks 2 and all supplementation diets on week 4. These results suggest that diet enriched with carotenoid pigment positively enhance the immune status and protects C. carpio from A. hydrophila infection.

Protective effect of chitin and chitosan enriched diets on immunity and disease resistance in Cirrhina mrigala against Aphanomyces invadans

The effect of diet enriched with 1% chitin or chitosan on innate immune response and disease resistance in Cirrhina mrigala against Aphanomyces invadans was investigated at weeks 1, 2, and 4. In the un-infected and infected groups the white blood cells (WBC), red blood cells (RBC), haematocrit (Ht), lympocytes, monocytes, and neutrophils significantly increased when fed with 1% chitin (CH) or chitosan (CT) enriched diet from weeks 1 to 4 when compared to control; however, the haemoglobin (Hb) and thrombocytes significantly increased only on weeks 2 and 4. The total protein and albumin levels also significantly increased with any enriched diet on weeks 2 and 4; but the globulin and albumin:globulin ratio increased on week 4 as compared to control; similarly the phagocytic activity significantly increased on weeks 2 and 4 while the lysozyme activity increased from weeks 1 to 4. The complement activity was significantly enhanced in CT and CTI fed groups on weeks 2 and 4. In un-infected fish fed with 1% CH and CT diets, the cumulative mortality was 10% and 5% whereas the infected fish suffered 20% and 25% mortality. The present results suggest that infected fish fed with 1% chitin or chitosan enriched diet modulates the immune system conferring disease resistance in C. mrigala against A. invadans.

Azadirachta indica (neem) leaf dietary effects on the immunity response and disease resistance of Asian seabass, Lates calcarifer challenged with Vibrio harveyi

The present study was aimed to address the possible evaluation of Azadirachta indica (neem) leaf-supplemented diets on innate immune response in Asian seabass, Lates calcarifer fingerlings against Vibrio harveyi infection. Fish were fed for two weeks diets containing six graded levels of neem leaf at 0 g, 1 g, 2 g, 3 g, 4 g and 5 g per kg feed. Fish fed neem leaf-supplemented diet displayed significant differences (p < 0.05) in weight gain, specific growth rate (SGR) and feed conversion ratio (FCR) compared to the control group fed without neem leaf-supplemented diet. Various innate immune parameters were examined pre-challenge and post-challenge. Fish was injected intraperitoneally with a lethal dose of V. harveyi containing 10(8) cells mL(-1). Supplementation of neem leaf diet significantly increased phagocytic activity, superoxide anion production, serum lysozyme, serum bactericidal activity, serum anti-protease activity throughout the experimental period when compared with the control group. Dietary doses of neem leaf diet significantly influenced the immune parameters, haematological parameters and blood biochemical indices of treated fish. The results suggested that fish fed neem leaf-supplemented diet improved the immune system and increased survival rate in L. calcarifer fingerlings against V. harveyi infection.

WITHDRAWN: Effects of saponin supplementation diet on hematological, biochemical, and immunological responses in Epinephelus bruneus against Vibrio alginolyticus

This article has been withdrawn at the request of the author(s) and/or editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.

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

This article has been withdrawn at the request of the author(s) and/or editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.

Effects of dietary bovine lactoferrin on growth, physiological performance, iron metabolism and non-specific immune responses of Siberian sturgeon Acipenser baeri

The present experiment was carried out to investigate the effects of different levels of dietary lactoferrin (LF) on growth performance, physiological status, iron absorption and innate immune response of juvenile Siberian sturgeon Acipenser baeri. Fish were fed with six different rations including 0, 100, 200, 400, 800 and 1600 mg LF kg(-1) diet for 8 weeks. At the end of the experiment, samples were collected for estimating the physiological and immunological parameters. Dietary LF did not change the fish growth performance, hematological parameters, serum proteins or hepatic enzymes. Moreover, stress indicators (plasma cortisol, glucose and lactate) were not affected by dietary LF. The iron absorption of fish was considerably affected by LF; thus, plasma iron in LF-treatments greatly declined and the total iron binding capacity (TIBC) significantly increased in fish fed with 800 mg LF kg(-1). In addition, the liver iron content markedly increased in some LF-treatments, but the variation of muscle iron concentration in treatments was insignificant. The amount of mucus secretion and serum bactericidal activity rose in fish fed on dietary LF, although other non-specific immune responses such as mucus bactericidal activity, serum and mucus lysozyme activity, serum peroxidase, serum natural hemolytic complement activity and serum IgM were not influenced by LF. This study revealed the ability of dietary LF to sequester iron, which is an essential nutrient required for the growth of bacteria. LF was also shown to improve some physiological and immunological parameters of Siberian sturgeon, to some extent.

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.

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.

Use of garlic, Allium sativum, to control Aeromonas hydrophila infection in rainbow trout, Oncorhynchus mykiss (Walbaum)

Garlic, Allium sativum, which was fed at 0, 0.05, 0.1, 0.5 and 1.0 g per 100 g of feed for 14 days to rainbow trout, Oncorhynchus mykiss (Walbaum), led to control of experimental infection with Aeromonas hydrophila. At doses of 0.5 and 1.0 g garlic per 100 g of feed, there was a reduction in mortalities to 4% compared with the controls (88%). Moreover, there was a significant increase in growth, feed conversion and protein efficiency. There was stimulation of the number of erythrocytes and leucocytes, a significantly higher haematocrit, enhancement of phagocytic activity, respiratory burst, lysozyme, anti-protease and bactericidal activities following feeding with garlic.

Milk biologically active components as nutraceuticals: review

Milk contains components that provide critical nutritive elements, immunological protection, and biologically active substances to both neonates and adults. Milk proteins are currently the main source of a range of biologically active peptides. Concentrates of these peptides are potential health-enhancing nutraceuticals for food and pharmaceutical applications. Several bioactive peptides may be used as nutraceuticals, for example, in the treatment of diarrhea, hypertension, thrombosis, dental diseases, as well as mineral malabsorption, and immunodeficiency. Minor whey proteins, such as lactoferrin, lactoperoxidase, lysozyme, and immunoglobulins, are considered antimicrobial proteins. Milk also contains some natural bioactive substances. These include oligosaccharides, fucosylated oligosaccharides, hormones, growth factors, mucin, gangliosides, and endogenous peptides, which are present in milk at secretion. Most of the claimed physiological properties of milk bioactive components have been carried out in vitro or in animal model systems, and these hypothesized properties remain to be proven in humans. Whether these milk bioactive components will replace drugs entirely in the immediate future is still unclear, but the increasing appreciation of "drug foods" or nutraceuticals plays a complementary rather than a substitutional role to the synthetic pharmacological drugs.

Use of a probiotic to control lactococcosis and streptococcosis in rainbow trout, Oncorhynchus mykiss (Walbaum)

From a comparison of 125 bacterial isolates recovered from the digestive tract of rainbow trout, Oncorhynchus mykiss, and carp, Cyprinus sp., a culture was obtained which was effective at preventing clinical disease caused by Lactococcus garvieae and Streptococcus iniae when used as a feed additive. The culture, Aeromonas sobria GC2, was incorporated into the feed and fed to rainbow trout (average weight = 20 g) for 14 days at a dose equivalent to 5 x 10(7) cells g(-1) of feed. Whereas the untreated controls experienced losses of 75-100% when challenged intraperitoneally with L. garvieae and S. iniae, the probiotic-treated groups remained healthy with total mortalities of only 0-6%. Formalized and sonicated preparations of GC2 and cell-free supernatant fared less well. The mode of action reflected stimulation of innate immunity, namely an increased number of leucocytes and enhanced phagocytic and respiratory burst activity.

Effects of lactoferrin on non-specific immune responses of gilthead seabream (Sparus auratus L.)

The main innate cellular immune responses of gilthead seabream (Sparus auratus L.) leucocytes were evaluated after in vitro incubation with human lactoferrin (Lf). Isolated head-kidney leucocytes were incubated with 0 (control) to 1 mg ml(-1) Lf-supplemented culture medium for 30, 120, 240 or 360 min and assayed for viability, peroxidase content, and respiratory burst, phagocytic and cytotoxic activities. Only respiratory burst activity was found to increase when using the highest Lf concentration (1 mg ml(-1)) and long incubation times (more than 120 min). Seabream were fed Lf-supplemented diets (0, control, 50, 100 or 200 mg kg(-1) diet). After 1 or 2 weeks of administration the leucocyte peroxidase content, respiratory burst, phagocytic and cytotoxic activities as a measure of cellular immune responses, as well as serum peroxidase and complement activity as a measure of humoral immune responses were evaluated. The results showed that Lf feeding at 100 mg kg(-1) diet for 1 week enhanced the cellular innate immune responses although only the cytotoxic activity did so significantly. The humoral immune response was not influenced by Lf feeding. In conclusion, Lf seems to affect innate immune cellular activity, mainly respiratory burst and natural cytotoxic activity. The possible use of Lf as an immunostimulant for farmed gilthead seabream is discussed.

Dietary bovine lactoferrin induces changes in immunity level and disease resistance in Asian catfish Clarias batrachus

The effects of including bovine lactoferrin (Lf) in the diet of the Asian catfish (Clarias batrachus) on specific and non-specific immunity as well as disease resistance were investigated. The catfish were fed four different diets for 2 weeks: a commercial diet as control and the same diet supplemented with 50, 100 and 200mg bovine Lf/kg feed. After 1 and 2 weeks, serum bacterial agglutination titre against Aeromonas hydrophila as a measure of specific immunity; natural serum haemolysin titre, lysozyme activity and oxidative radical production by neutrophils as a measure of non-specific immunity as well as disease resistance against A. hydrophila challenge to vaccinated and non-vaccinated animals were evaluated. The results showed that Lf supplements, particularly at 100mg level, significantly (P<0.05) enhanced serum lysozyme level, oxidative radical production and level of protection against A. hydrophila challenge in non-vaccinated animals irrespective of length of exposure. The specific immunity was not influenced by Lf feeding as evidenced from the bacterial agglutination titre and level of protection in vaccinated animals. As Lf feeding at 100mg/kg for 1 week is able to enhance the non-specific immunity and disease resistance of catfish efficiently, these results support the possible use of Lf as an immunostimulant for farmed catfish.

Oral administration of formalin-inactivated cells of Aeromonas hydrophila A3-51 controls infection by atypical A. salmonicida in goldfish, Carassius auratus (L.)

There has been increasing interest in the use of probiotics in aquaculture to control fish diseases (e.g. Douillet Langdon 1994; Gildberg, Mikkelsen, Sandaker & Ringo 1997; Kennedy, Tucker, Neidic, Vermeer, Cooper, Jarrell & Sennett 1998; DeSchrijver & Ollevier 2000; Robertson, O'Dowd, Burrells, Williams & Austin 2000), and a diverse range of Gram-positive (such as Carnobacterium inhibens) (Robertson et al. 2000) and Gram-negative bacteria, including Vibrio alginolyticus (Garriques & Arevalo 1995), have been evaluated at various times. However, the possible use of probiotics to control diseases of ornamental fish has been neglected. Consequently, following previous success with live (Irianto & Austin 2002) and inactivated probiotics in salmonids (Irianto & Austin, in press), research has focused on the usefulness of inactivated bacterial preparations for the control of atypical Aeromonas salmonicida infections in goldfish, Carassius auratus (L.). Goldfish, of average 40-50 mm in length, were obtained from a commercial farm in England, and maintained in aerated re-circulating dechlorinated fresh water at 17 degrees C. Their health status was examined immediately upon arrival in the aquaria and at 1-2-week periods thereafter (after Austin & Austin 1989).

Fish immunology. I. Binding and engulfment of Candida albicans by erythrocytes of rainbow trout (Salmo gairdneri Richardson)

The role of fish erythrocytes (FE) as phagocytic cells has poorly been investigated, until now. Here, we have focussed our attention on the interplay between rainbow trout (Salmo gairdneri Richardson) erythrocytes and Candida albicans (CA). At the same time, the intervention of autologous head kidney macrophages (MO) in the CA processing by FE has been studied. Data show that CA particles bind to FE, which, in turn, are able to engulf but not kill them. In the presence of MO, a decrease of FE with bound CA occurs and, in some microscopic images, FE form rosettes with MO. Phagocytosis of CA is higher in rosetting MO than in non-rosetting ones. According to our findings, it appears that FE represent a reservoir of engulfed CA and rosetting is an efficacious phenomenon of presentation of pathogens to MO, where an effective clearance of them can take place.

Innate host defense mechanisms of fish against viruses and bacteria

The integumental defenses provide a physical and chemical barrier to the attachment and penetration of microbes. Besides the entrapping and sloughing of microbes in the mucus, the latter contains many antibacterial substances including anti-bacterial peptides, lysozyme, lectins and proteases. The gastro-intestinal tract is a hostile environment of acids, bile salts and enzymes able to inactivate and digest many viruses and bacteria. In most cases the integumental defenses are sufficient to protect against even quite virulent organisms which often only produce disease when the integument has been physically damaged. If a microbe gains access to the tissues of the fish, it is met with an array of soluble and cellular defenses. The complement system, present in the blood plasma, plays a central role in recognising bacteria and its activated products may lyse the bacterial cells, initiate inflammation, induce the influx of phagocytes and enhance their phagocytic activity. Complement can be activated directly by bacterial products and constituents and also indirectly by other factors, principally C-reactive protein and lectins, which can also bind to the bacterial surface. Plasma also contains a number of factors which inhibit bacterial growth(e.g. transferrin and anti-proteases) or which are bactericidal e.g. lysozyme. Following the infection of fish with virus pathogens, infected cells produce interferon. This induces antiviral defenses in neighbouring cells which are then protected from becoming infected. Anti-viral cytotoxic cells are able to lyse virally infected cells and thus reduce the rate of multiplication of virus within them. Innate defenses thus provide a pre-existing and fast-acting system of protection which is non-specific and relatively temperature-independent and thus has several advantages over the slow-acting and temperature-dependent specific immune responses.

In vivo antimicrobial and antiviral activity of components in bovine milk and colostrum involved in non-specific defence

The in vivo evidence of the antimicrobial and antiviral activity of bovine milk and colostrum derived components are reviewed with special emphasis on lactoferrin and lactoperoxidase. Their mode of action and the rationale for their application in efficacy trials with rodents, farm animals, fish and humans, to give protection against infectious agents, are described. A distinction is made between efficacy obtained by oral and non-oral administration of these non-specific defence factors which can be commercially applied in large quantities due to major achievements in dairy technology. From the in vivo studies one can infer that lactoferrin and lactoperoxidase are very promising, naturally occurring antimicrobials for use in fish farming, husbandry, oral hygiene and functional foods. Other promising milk-derived compounds include lipids, from which anti-infective degradation products are generated during digestion, and antimicrobial peptides hidden in the casein molecules.

Horseradish peroxidase binding to intestinal brush-border membranes of Cyprinus carpio. Identification of a putative receptor

Morphologic studies have shown that the classic endocytosis tracer horseradish peroxidase (HRP) is actively internalized by vesicular transport in the carp intestine, suggesting the existence of specific binding sites in the apical membrane of enterocytes. The aim of the present study was to develop an in vitro binding assay using isolated carp intestinal brush-border membranes (BBM) to demonstrate and characterize these specific HRP binding sites. The results obtained show that HRP binding to BBM exhibits a saturable mode and high affinity (K(d) = 22 nM). In addition, HRP binding sites are highly enriched in BBM compared to basolateral membranes. On the other hand, HRP interaction with these sites is apparently of an ionic character because binding increased concomitantly with decreasing NaCl concentrations in the assay, reaching a maximum in the absence of NaCl. Other proteins that are also internalized in carp intestine did not significantly inhibit HRP binding to BBM. A lectin-type of interaction was discarded because neither manan nor ovoalbumin inhibited HRP binding. Proteinase K treatment of BBM reduced HRP binding by 70%, suggesting a proteic nature for this binding site. Finally, ligand blotting assays showed that HRP binds specifically to a 15.3-kDa protein. Taken together, these results are consistent with the existence of a functional receptor for HRP in carp intestinal mucosa that could mediate its internalization.

Bovine lactoferrin stimulates the phagocytic activity of human neutrophils: identification of its active domain

Bovine LF (bLF) at concentrations in the range of 50-250 micrograms/ml enhanced the phagocytic activity of human neutrophils as determined by measuring the incorporation of FITC-labeled latex beads by flow cytometry. The stimulatory effect of bLF was not abrogated by hydrolysis with pepsin. Bovine lactoferricin (bLFcin), which is a bactericidal fragment purified from a pepsin hydrolysate of bLF (bLFH), also enhanced the phagocytic activity, whereas, in contrast, the fraction of bLFH depleted of bLFcin showed no stimulatory effect. The phagocytosis-enhancing activity of bLF still remained after washing the neutrophils, following exposure to bLF. Also, bLF pretreatment of the latex beads stimulated their uptake. These results demonstrate that bLF is effective in promoting the phagocytic activity of human neutrophils. This activity appears to be due to its bLFcin domain and may involve dual mechanisms of direct binding to neutrophils and opsonin-like activity.