Immune Response Of Tilapia Research Articles

Simultaneous Administration of Boesenbergia pandurata Extract and Vaccination to Stimulate Immune Response in Tilapia, Oreochromis niloticus.

The use of adjuvants or immunostimulants is often necessary to increase vaccine efficacy, in this study we evaluated the improvement of the immune response in tilapia treated by either oral and immersion administration with vaccine and Boesenbergia pandurata extract (BPE). The initial concentration of BPE and the cell density of vaccine were 900 mg L-1 and 104 CFU mL-1 for oral administration while 106 CFU mL-1 for immersion, respectively. The extract and vaccine were mixed homogeneously in a ratio of 1:1. Further, the mixture was supplemented to feed at 1 mL g-1 feed. Tilapia with average initial body weight of 15 g were fed containing vaccine and BPE 3 times a day. The other group of fish was immersed with vaccine and BPE for 20 min. After 7th (d7), 14th (d14) and21th (d21) days of treatment, a challenge test was conducted by intramuscularly injection of 0.1 mL of Aeromonas hydrophila and Pseudomonas fluorescens mixture (1:1) at a density of 105 CFU mL-1. Antibody levels, total white blood cell (WBC) and phagocytic activity (PA) were evaluated to determine the immune improvement of the fish. Furthermore, relative percent survival (RPS) and the survival rate (SR) were evaluated at week 2 and 4 after challenge test. Results indicated that the all parameters of tilapia immune system were increased (p<0.05) after 2-4 weeks of both administration methods. Meanwhile, the efficacy of the vaccine has increased by combining BPE treatment using immersion method better than oral method. The RPS of vaccination plus extract by immersion was 83-100% and by oral administration was 83-87%. The present results implied that B. pandurata extract boost the efficacy of the Pseudomonas sp. vaccine by increasing the immune system and diseases resistance in tilapia.

Efficacy of live attenuated vaccine derived from the Streptococcus agalactiae on the immune responses of Oreochromis niloticus

Streptococcus agalactiae species have been recognized as the main pathogen causing high mortality in fish leading to significant worldwide economical losses to the aquaculture industries. Vaccine development has become a priority in combating multidrug resistance in bacteria; however, there is a lack of commercial live attenuated vaccine (LAV) against S. agalactiae in Malaysia. The aim of this study is to compare two methods using attenuated bacteria as live vaccine and to evaluate the efficacy of selected LAV on the immune responses and resistance of Oreochromis niloticus (tilapia) against S. agalactiae. The LAV derived from S. agalactiae had been weakened using the chemical agent Acriflavine dye (LAV1), whereas the second vaccine was weakened using serial passages of bacteria on broth media (LAV2). Initial immunization was carried out only on day one, given twice-in the morning and evening, for the 42 day period. Serum samples were collected to determine the systemic antibody (IgM) responses and lysozymal (LSZ) activity using ELISA. On day 43 after immunization, the fish were injected intraperitoneally (i.p) with 0.1 mL of S. agalactiae at LD50 = 1.5 × 105 (CFU)/fish. Fish were monitored daily for 10 days. Clinical signs, mortality and the relative percent of survival (RPS) were recorded. Trial 1 results showed a significant increased (P < 0.05) in serum IgM titers and LSZ activity as compared to LAV2 and the control group (unvaccinated fish). The efficacy of LAV1 was proven effective as determined by the RPS values, LAV1 at 81.58% as compared to LAV2 at 65.79%. Trial 2 of LAV1 and control group were further determined by administering primary and booster doses revealed a RPS value for LAV1 of 82.05%, with the significant enhancement on the immune responses of tilapia as compared to control group. In conclusion, LAV revealed to elevate antibody IgM levels, LSZ activity and provide long-term protection when added to feed. LAV is a low-cost vaccine shown to rapidly increase the immune response of fish and increase survival rates of fish against S. agalactiae infection.

The effects of the dietary supplementation of Echinacea purpurea extract and/or vitamin C on the intestinal histomorphology, phagocytic activity, and gene expression of the Nile tilapia

In this study, the influence of the dietary incorporation of Echinacea purpurea (EP) extract and/or vitamin C on the intestinal histomorphology and some immunological indices were tested in the Nile tilapia (Oreochromis niloticus Linn.). O. niloticus were randomly divided into four groups. The control group G1 was fed on a basal diet, while the G2 and G3 were fed on basal diets, supplemented with EP extract and vitamin C at the doses of 500 mg kg−1 and 400 mg kg−1, respectively. Meanwhile, G4 was fed on a basal diet, supplemented with a mixture of EP extract and vitamin C. After 28 days of feeding, the intestinal tissues were collected for histological observation and immune status, was based on an assay for measuring the phagocytic activity. Furthermore, the expression of the transforming growth factor-beta 1 (TGF-β1), interleukin-1beta (IL-1β), and tumor necrosis factor alpha (TNF-α) genes was evaluated in intestine and head kidney. The results revealed that the G4 successfully surpassed the other groups in terms of the heights of intestinal villi, the number of goblet cells and intraepithelial lymphocytes (IELs), and the phagocytic activity, followed by the G3 and G2. The expression of the IL-1β and TNF-α genes were up regulated only in G4 but in the G3 only the expression of the IL-1β gene was up regulated. Hence, EP extract along with vitamin C could be used as a feed additive in order to improve the structure of the intestinal mucosal epithelium and immune response in tilapia.

Discovery of immunoglobulin T in Nile tilapia (Oreochromis niloticus): A potential molecular marker to understand mucosal immunity in this species

Immunoglobulin molecules play an important role in the immune defense system in all jawed vertebrates, by protecting the organism from a wide variety of pathogens. Nile tilapia (Oreochromis niloticus) is extensively cultivated worldwide, with a strong established market demand. It constitutes one of the model species for the study of fish immunology and its genome is currently fully sequenced. The presence of the immunoglobulin M gene in this species is well documented, as well as its major role in systemic immunity. To date, the IgT gene from O. niloticus has not been identified and, therefore, no information is available on the role of this immunoglobulin isotype in the immune response in tilapia. In the present work, novel secreted and membrane immunoglobulin T isotypes and a fragment of IgM were isolated from tilapia head kidney lymphocytes. Their transcriptional profiles were analyzed by quantitative PCR in larval development and in different tissues of healthy or lipopolysaccharide/Edwardsiella tarda-challenged tilapia adults. The presence of IgT and IgM were detected in early stages of larval development. Additionally, these genes exhibited differential expression profiles in basal conditions and after E. tarda infection in adult tilapia, in accord with the proposed effector functions of these immunoglobulins in the systemic and mucosal compartments. Our results suggest the potential involvement of this new Ig in mucosal immunity in tilapia.

Dietary carbohydrates and protein of yeast modulate the early stages of innate immune response in tilapia (Oreochromis niloticus) primarily after LPS inoculation

The administration of yeast-derived immunostimulants leads to improvement of the immune system and growth performance preventing the antibiotics misuses. The objective of this study was to evaluate the effects of dietary Actigen® [0, 0.04, 0.06 and 0.08 % of Actigen (ACT)], on the immunological and physiological responses and growth performance of tilapia after lipopolysaccharide (LPS) inoculation. The experiment was conducted in two trials. In the first trial, the ACT was offered for 30 and 60 days; in the second trial, the ACT was offered for 60 days, and then fish were challenged by intraperitoneal injection with LPS and sampled at 5 and 12 days after inoculation. After the first trial, immunological, hematological and biochemical parameters, intestinal morphology and the growth performance were assessed, whereas in the second trial, immunological, hematological and biochemical parameters were assessed. Supplementation of diets with ACT showed a significant effect mainly after 60 days of feeding, with increased lysozyme, globulin, HTC, MCV, erythroblasts, leukocytes, lymphocytes and monocytes. A general decrease in cells and globulin occurred at 5 days after the LPS challenge, with partial recovery at 12 days after the challenge. In addition, the study demonstrated that the use of ACT, an extract derived from yeast cell walls and containing active mannan protein and carbohydrates, effectively increased the immune parameters evaluated, indicating a possible beneficial effect on fish health.

The dietary effect of ulvan from Ulva clathrata on hematological-immunological parameters and growth of tilapia (Oreochromis niloticus)

An extract of ulvan obtained from the green alga Ulva clathrata was lyophilized and confirmed by Fourier transform infrared spectrometry (FTIR) and 1H-nuclear magnetic resonance (NMR). The percentage of sulfate groups calculated by elemental quantitative analysis in the lyophilized ulvan was twice (8 %) than that of dry algae (4 %). The dietary effect of ulvan on hematology, immunology, and growth was evaluated in tilapia (Oreochromis niloticus). The fish (25 ± 3 g) were fed a commercial diet (negative control group), and the diet was supplemented with three levels of ulvan (0.1, 0.5, and 1 % kg−1 feed). Additionally, a positive control with yeast (Saccharomyces cerevisiae, 2 % kg−1 feed) was included. During a trial period of 90 days (60 days of treatment + 30 days of suspended treatment), hematocrit (Ht), hemoglobin (Hb), red blood cell (RBC) count, white blood cell (WBC) count, total serum protein (TP), albumin (Al), globulin (Gb), and phagocytic activity (Pa) were measured. After 15 days of treatment until the 60th day, the Pa was increased (P < 0.001) in fish with diets containing 0.1, 0.5, and 1 % ulvan. An increase (P < 0.001) in the WBC count was observed at day 30 in fish with diets containing 0.1, 0.5, and 1 % ulvan; which maintained for 15 days in 0.5 and 1 % ulvan after their dietary suspension. There was no significant difference (P < 0.05) in growth performance among fish for any of the diets tested. This is the first report of an increment in the immune response by a dietary supplementation with ulvan from U. clathrata in the Nile tilapia. These results demonstrate the potential activity of ulvan on at least two mechanisms of the immune response in tilapia and the time over which the activity is sustained in the organism after suspension of supplementation.

Immune Response in Tilapia, Oreochromis niloticus, Induced by the Surface Immunogenic Protein (Sip) of Streptococcus agalactiae

The main aim of this study was to demonstrate that the surface immunogenic protein (Sip) of the aquatic pathogen Streptococcus agalactiae is a potential candidate for vaccine development for Oreochromis niloticus. In this study, a Sip was identified. Alignment analysis indicated that the Sip protein was highly homologous with Sip proteins from other S. agalactiae isolated from humans (99%). SDS-PAGE procedure indicated that the Sip protein was successfully expressed in Escherichia coli BL21 (DE3). The recombinant Sip protein was purified by affinity chromatography, and the mouse anti-Sip serum was produced. Tilapia Oreochromis niloticus were vaccinated with Sip, and immunogenicity was confirmed by subsequent western blotting. Enzyme-linked immunosorbent assay (ELISA) analysis demonstrated that Sip produced an observable antibody response in all sera of the vaccinated fish. The relative percentage survival (RPS) value for the Sip vaccine was 90.62. Tilapia vaccinated with Sip produced specific antibodies, and were highly resistant to infection by the virulent S. agalactiae. These results indicate that Sip is an effective vaccine candidate against S. agalactiae for tilapia, Oreochromisniloticus.

Effects of recombinant tHsp70 on immune function of tilapia peritoneal macrophages

We used recombinant tilapia Hsp70(tHsp70) from Pichia yeast to prepare non-covalent HSP70-antigen complexes with thallus and extracellular bacterial products(ECP) of Streptococcus iniae.We investigated the ef-fects of the antigen complexes on the cellular immune response of tilapia by detection of NO release,phagocytic activity,and related immune gene expression of peritoneal macrophages in vitro.tHsp70 can form complexes with the thallus and ECP of tilapia in vitro.In addition,tHsp70 alone and its complexes significantly stimulated growth and attachment of peritoneal macrophages and enhanced NO release and phagocytic activity of peritoneal macro-phages.In contrast,treatment with ECP significantly inhibited NO release and led to cell death,while treatment with tHsp70-ECP complex reduced the cell death.Moreover,tHsp70 alone or tHsp70-antigen complexes signifi-cantly increased the expression of immune related genes(IL-8,Hsp70,CXCR4,and PGRN) in tilapia peritoneal macrophages compared to antigen only and medium control groups.Our results suggest that tHsp70 has an im-munoadjuvant and immunopotentiator function,and provides experimental data for development of a tHsp70 based vaccine against tilapia streptococcal diseases.

Rapid decreases in salinity, but not increases, lead to immune dysregulation in Nile tilapia, Oreochromis niloticus (L.)

Rapid changes in salinity, as with other environmental stressors, can have detrimental effects on fish and may trigger increased susceptibility to disease. However, the precise mechanisms of these effects are not well understood. We examined the effects of sudden increases or decreases in salinity on teleost immune function using Nile tilapia, Oreochromis niloticus (L.), as the fish model in a battery of bioassays of increasing immune system specificity. Two different salinity experiments were performed: one of increasing salinity (0 to 5, 10 and 20gL(-1) ) and one of decreasing salinity (20 to 15, 10 and 5 gL(-1) ). Histopathology of anterior kidney, gills, gonads, intestines and liver of exposed fish was performed, but no remarkable lesions were found that were attributable to the salinity treatment regimes. The spleen was removed from each fish for analysis of cytokine expression, and peripheral blood was used for haematology, cortisol and phagocytosis assays. In the increasing salinity experiments, no significant changes were observed in any immune system assays. However, in the decreasing salinity experiments, lymphopenia, neutrophilia and monocytosis were observed in the peripheral blood without modification of the packed cell volume, plasma protein or plasma cortisol levels. Phagocytosis was increased in response to decreases in salinity from 20gL(-1) to 15gL(-1) , 10gL(-1) and 5gL(-1) , whereas phagocytic index was not significantly altered. Transforming growth factor-β (TGF-β) transcription increased during the same decreases in salinity. However, the TGF-β value at 5gL(-1) was less than those in the 15 and 10gL(-1) salinity treatments. Interleukin-1β (IL-1β) transcription did not significantly respond to either salinity regime. In total, acute salinity changes appeared to trigger reactive dysregulation of the immune response in tilapia, a situation which, when combined with additional co-occurring stressors such as sudden changes in temperature and/or dissolved oxygen, could make fish more susceptible to infectious diseases. Accordingly, these findings may help to explain how sudden environmental changes may initiate disease outbreaks and lead to critical declines in cultured or wild fish populations.

Modulation of intestinal morphology and immunity in nile tilapia (Oreochromis niloticus) by Lactobacillus rhamnosus GG

The use of lactic acid bacteria from human origins as a potential probiotic supplementation in aquaculture feed is now widely accepted. Here, we examined some of the properties and mechanisms of the action of Lactobacillus rhamnosus GG, originating from humans, on growth performance, gut mucosal immunity and humoral and cellular immune response in tilapia (Oreochromis niloticus). The results suggested that supplementation of L. rhamnosus gave an advantage in promoting the intestinal structure and the mucosal immunity of tilapia. Probiotic fish had a greater villous height in all parts of the intestines and, significantly, in the proximal and middle part. The population of intraepithelial lymphocytes was significantly higher in the probiotic group than in the control group in all parts of the intestines. The population of acidophilic granulocyte in the probiotic group was significantly higher at the proximal and distal parts when compared with the control group. The higher serum complement activity as well as the enhanced phagocytosis and killing ability of the head kidney leukocytes in the probiotic supplemented fish corresponded with the higher level of TNF alpha and IL-1 gene expression, suggesting that the induction of IL-1 and TNF alpha cytokines by L. rhamnosus served as an important regulator of gut associated immune systems.

Effect of various dietary vitamin A levels on growth performance and immune response of tilapia (Oreochromis niloticus)

Six purified vitamin-free casein-based diets were formulated to contain six levels vitamin A at 0, 500, 1000, 2000, 4000, and 8000 IU·kg−1, respectively. Tilapias (initial mean weight: 7.73±0.03 g) were fed the diets in quadruplicate aquaria to apparent satiation twice daily for 10 weeks. No differences in mortality, weight gain, or feed efficiency ratio (FER) were observed among the groups. Liver vitamin A levels reflected dietary vitamin A levels. Immune parameters, such as hemoglobin levels, total cell count, red blood cell count, total serum protein, and serum lysozyme activity, did not vary with the dietary vitamin A levels. White blood cell counts of fish in 2000 IU·kg−1 diet groups were significantly higher than that in other diets groups. Serum complement activities of fish in 2000 and 4000 IU·kg−1 vitamin A diet groups were also higher than those in other diet groups. After the 14-d challenge test, the mortality and antibody titer were similar among the treatments. The results indicated that dietary vitamin A inclusions did not affect the immune response of Oreochromis niloticus.

Effect of probiotics, Enteroccus faecium, on tilapia ( Oreochromis niloticus) growth performance and immune response

The aim of this study was to analyze the effect of a probiotic bacterium, Enterococcus faecium ZJ4 on growth performances and immune responses of tilapia ( Oreochromis niloticus). The tilapias were treated with E. faecium ZJ4 at a final concentration of 1 × 10 7 cfu ml − 1 in aquaria water every 4 days. Six aquaria with three replicates for treated and controls were used. After 40 days, the tilapias supplemented with the probiotic showed significantly better final weight and daily weight gain (DWG) than those fed the basal diet (Control) ( P < 0.05). There was no remarkable difference ( P > 0.05) in the total serum protein, albumin content, globulin concentration and A/G ratio between the treated and control tilapias. The result of lysozyme activity assay was similar to these biochemical indexes. However, the complement component 3 content, myeloperoxidase (MPO) activity and the respiratory burst activity of blood phagocytes were higher ( P < 0.05) in E. faecium treated tilapias (trial 1) than the controls.

Effect of fish feed containing two Chinese herbal extracts (Ganodema Iucidum and Lonicera japonica) on the non-specific immune system of Nile tilapia, Oreochromis niloticus (preliminary results)

The effect of two Chinese herbs (Ganoderma lucidum and Lonicera japonica) on non-specific immune response of tilapia was examined. In addition to the control (no herbs), three diet variations were used. These contained 1.0% of Lonicera, 1.0% of Ganoderma and a mixture of Ganoderma (0.5%) and Lonicera (0.5%). The respiratory burst and phagocytic activity of blood leukocytes were monitored. Three weeks after feeding, the fish were infected with Aeromonas hydrophila. The results of this study showed that feeding tilapia with Ganoderma and Lonicera alone or in combination enhanced the phagocytosis of blood leukocytes, but not the respiratory burst activity. Both herbs, when used alone or in combination, reduced mortality after challenge with A. hydrophila. The highest mortality was observed in the control fish – 56.66%, and fish fed with Lonicera extract – 43.33% while 30% of fish died in the group fed with Ganoderma and the lowest mortality (20%) was observed when the fish were fed with a combination of the two herbs. It can be concluded that the herb extracts added to this diet act as immuno-stimulants and appear to improve the immune response and disease resistance of tilapia.

Immune response in the tilapia, Oreochromis mossambicus on exposure to tannery effluent

The objective of the study was to investigate the effect of chronic exposure to sublethal concentrations of tannery effluent (TE) on the specific immune response and nonspecific immunity in tilapia, Oreochromis mossambicus. The effluent from the tannery was collected directly from a chrome-tanning factory situated in Dindigul district, Tamil Nadu, India. Apart from chromium (88.2 ppm), the effluent contained appreciable amount of calcium carbonate and sodium sulphate. Groups of fish (45–50 g) were exposed to 0.0053, 0.053 or 0.53% [0.1%, 1% or 10% LC 50] of TE for 28 days. The specific immune response of fish was assessed by antibody response to heat-killed Aeromonas hydrophila by ELISA and bacterial agglutination assay. Nonspecific immune mechanisms were assessed in terms of serum lysozyme activity, production of intracellular reactive oxygen species (ROS) and reactive nitrogen intermediates (RNI) by peripheral blood leucocytes (PBL). The results indicate that chronic exposure of fish to 0.53% of TE, significantly suppressed antibody response, nonspecific serum lysozyme activity, and ROS and RNI production. Exposure to 0.053% (1% LC 50) of TE also caused a similar suppressive effect though at a lesser degree. In conclusion, the study shows, that exposure to sublethal concentrations of TE, can lead to adverse effects on selected immune reactions in tilapia. Further, these findings may be important in terms of monitoring fish health and risk assessment during periods of fluctuating levels of pollutants in the natural and farm environments.