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1.
The purpose of present study was to ascertain whether the response of gastrointestinal (gut) melatonin to altered feeding conditions was related to the levels of different antioxidants and digestive enzymes in the same gut tissues of a sub-tropical carp (Catla catla). Accordingly, the fish were subjected to food deprivation for 4 or 8 days and separately to re-feeding for 4 or 8 or 12 days after deprivation of food for 8 days, and their gut tissue homogenates were used to measure the levels of melatonin, both enzymatic [superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione S-transferase (GST)] and non-enzymatic [reduced glutathione (GSH)] antioxidants, as well as different digestive enzymes (α-amylase, cellulase, protease, and lipase). Notably, the gut levels of melatonin, SOD, CAT, GPx, and GST underwent gradual increase with the progress of food deprivation, but a sudden fall after restoration of food supply for 4 days and a rise thereafter. Conversely, the activity of all the digestive enzymes significantly decreased after deprivation of food, but started increasing when food supply was reinforced. Gut melatonin concentrations by showing a positive correlation with the titers of different antioxidants (in both food-deprived and re-fed fish groups) and a negative (in food-deprived fish) or a positive (in re-fed fish) correlation with the activity of each digestive enzyme underlined possible physiological interplay between them. Collectively, our findings lend support to the hypothesis that gut melatonin response to altered feeding conditions in carp might be associated with the oxidative status as well as the digestive functions of the gastrointestinal tissues itself.  相似文献   

2.
To evaluate the effect of thermal and microbial stress on the immune response of common carp (Cyprinus carpio L.), relative mRNA expression level of pro-inflammatory cytokines [tumor necrosis factor alpha (TNF-α) and interleukin (IL)-1β] and other genes related to immune or stress response [inducible nitric oxide synthase (iNOS), heat shock protein 70 (Hsp70), superoxide dismutase one (SOD1), and glucocorticoid receptor (GR)] was measured by quantitative PCR (qPCR). In addition, total protein and total immunoglobulin level in blood plasma of experimental common carp was also assayed. All the above parameters were estimated 24 h post-challenge with Gram-negative bacterium, Aeromonas hydrophila. Common carp (54.89?±?6.90 g) were initially exposed to 20 °C (control group) and 30 °C (thermal stress group) water temperature for 30 days, followed by experimental challenge with 2.29?×?108 colony forming unit/mL (CFU/mL; LD50 dose) of A. hydrophila. Exposure of fish to thermal stress and subsequently challenge with A. hydrophila significantly (P?<?0.05) increases the IL-1β mRNA expression in head kidney and spleen of common carp by ~?39.94 and ~?4.11-fold, respectively. However, TNF-α mRNA expression in spleen decreased ~?5.63-fold in control fish challenged with A. hydrophila. Thermal stress and challenge with bacterium suppresses the iNOS and GR mRNA expression in spleen of common carp. Moreover, significant (P?<?0.05) increase in total protein content of blood plasma (~?43 mg/g) was evident in fish exposed to thermal stress and challenged with A. hydrophila. In conclusion, our study highlights the importance of elevated temperature stress and microbial infection in differential regulation of expression of several immunogenes in common carp.  相似文献   

3.
This study examined the effects of two probiotics (Virgibacillus proomii and Bacillus mojavensis) on the digestive enzyme activity, survival and growth of Dicentrarchus labrax at various ontogenetic stages in three separate experiments. These probiotics were incorporated as single or mixed into fish feed for a period of 60 days. The growth parameters, proximate composition of whole body, digestive enzymes and gut microbiology were monitored at regular. The increments in length and weight and the survival were significantly higher (P < 0.05), and the values of food conversions were significantly lower (P < 0.05) in fishes fed the probiotic. The administration of V. proomii and B. mojavensis in diet resulted in an increase (P > 0.05) in body ash and protein content and in the specific activity of phosphatase alkaline and amylase in the digestive tract of all the fishes. V. proomii and B. mojavensis persisted in the fish intestine and in the feed in high numbers during the feeding period (group 1: 5.8 × 104 CFU/ml, group 2: 9.6 × 104 CFU/ml, and group 3: 9.8 × 104 CFU/ml day 60). The two probiotics V. proomii and B. mojavensis were adequate for improved growth performance and survival and for healthy gut microenvironment of the host.  相似文献   

4.
The aim of this study is to explore the effect of Aeromonas hydrophila on the intestinal mucosal barrier structure and intestinal permeability in grass carp (Ctenopharyngodon idella). Histopathological examinations showed that A. hydrophila induced severe intestinal lesions, including inflammatory cell infiltration and intestinal villus fusion and swelling. Messenger RNA (mRNA) expression of the inflammatory cytokines TNF-α, IL-1β, IL-8, IL-10 and MyD88 was significantly increased after infection with A. hydrophila. The permeability of intestinal mucosa was determined using Evans blue (EB) and d-lactic acid. The results indicated that the levels of EB and serum d-lactic acid were significantly increased after infection with A. hydrophila (p < 0.05). Our results also indicated that the intestinal mucosal barrier injury induced by A. hydrophila infection was closely associated with the expression of the tight junction (TJ) protein zonula occludens-1 (ZO-1), occludin, claudin b and claudin c as well as the activity of Na+, K+-ATPase and Ca2+, Mg2+-ATPase. Lower mRNA levels of occludin and lower Na+, K+-ATPase and Ca2+, Mg2+-ATPase activity in the intestines were observed after challenge. ZO-1 and claudin c were significantly increased 24 h after infection with A. hydrophila. The most interesting finding was that claudin b also significantly increased 24 h after challenge and then decreased to lower levels at 72, 120 and 168 h post-infection compared to the PBS-treated control group. The results demonstrated that grass carp infection with A. hydrophila induced intestinal inflammation and impaired the structure and function of the intestinal mucosal barrier.  相似文献   

5.
Aeromonas hydrophila are known for being opportunistic pathogens, harboring various virulence factors and triggering lesions and death in fish. The disease caused by bacteria can make fish inappropriate for human consumption, besides representing a risk to public health. The pathogenesis can be influenced by environmental variables, affecting fish productivity and mortality. The present study aimed to determine whether A. hydrophila harbor the virulence genes aerolysin, hydrolipase, elastase, lipase, cytotonic enterotoxin (ast), lateral flagellum (laf), and polar flagellum (fla) and to evaluate the influence of environmental variables on in vitro growth, in vivo virulence and expression of some of these genes. Polymerase chain reaction (PCR)-based screening for the presence of these virulence genes was performed on 35 isolates. Six isolates containing different profiles of virulence genes were tested for in vitro growth under different conditions of pH, temperature, and ammonia and for in vivo virulence under these same environmental conditions. RT-qPCR was used to quantify the expression of aerolysin, lipase, and fla genes. All the tested environmental factors influenced the growth of A. hydrophila, while pH and ammonia concentrations influenced the bacterial virulence. The expression of the fla gene increased when bacteria were grown in higher ammonia concentration. The mortality established by Aeromonas is influenced by several environmental factors pinpointing the importance of its control in fish farming to avoid higher economic loses associated to bacterial disease outbreaks.  相似文献   

6.
The present study was carried out to evaluate the effect of dietary taurine (Tau) on performance, digestive enzymes, antioxidant activity, and resistance of common carp, Cyprinus carpio L., fry to salinity stress. Fish (0.97?±?0.033 g) were fed on different taurine levels of 0.0 (control), 5, 10, 15, or 20 g/kg diet up to satiation twice daily for 8 weeks. At the end of the feeding trial, fish were stressed by exposure to 10 ppt salinity for 3 days during which fish mortality was observed. Fish performance was significantly (P?<?0.05) improved by dietary taurine up to 15 g Tau/kg diet after which fish growth and feed intake were almost the same. Also, taurine supplementation significantly (P?<?0.05) elevated activities of intestinal amylase, lipase, and protease resulting in an improving in feed intake giving better performance. Furthermore, Tau-stimulated antioxidant activity of common carp was observed in a dose-related manner, where activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) were significantly (P?<?0.05) higher, but malondialdehyde (MDA) value was significantly (P?<?0.05) lower in Tau-fed fish groups than those fed the control diet. In salinity stress experiment, highest survival rate was observed at fish fed Tau-supplemented diets without significant (P?>?0.05) differences over fish fed the control diet. It appears that taurine could be used as a feed supplement to confer better growth and health of common carp fry with optimal level of 15 g/kg diet.  相似文献   

7.
In this study, we developed a simple, low-cost, and rapid flow through immunogold assay (FIA) for detection of Aeromonas hydrophila in fish tissues and validated. The developed assay relied on colloidal gold conjugated highly specific monoclonal antibody (B8E3) against 20 kDa protein of A. hydrophila. The assay can be completed within 5 min including antigen (sample) preparation and exhibited no cross-reaction with other major aquatic pathogens such as Vibrio anguillarum, V. parahaemolyticus, V. harveyi, white spot syndrome virus (WSSV), and Aphanomyces invadans. A wider range of Aeromonas species were tested including A. caviae, A. dhakensis, A. sobria, A. veronii, A. culicicola, A. sharmana, and A. schubertii and no cross-reactivity could be observed. The developed technique FIA could detect 103 CFU/ml of aeromonad cells. In addition, the FIA is as sensitive as the first-step polymerase chain reaction (PCR) and 1000 times sensitive than the immunodot blot method. The validation study revealed the accuracy of FIA by comparing with the standard first-step PCR. The proposed FIA is low-cost, easy-to-use, and compatible for field-level analysis of A. hydrophila in fish tissues. Our developed FIA could successfully detect A. hydrophila at early stage of the infection and could be easily availed by farmers, fish producers, non-technicians, and technicians in the aquaculture industry.  相似文献   

8.
Transferrin (Tf) plays an important function in iron homeostasis and metabolism of organisms. In this study, we identified and characterized the Tf gene in Megalobrama amblycephala and evaluated its expression in basal conditions as well as after iron overload and experimental infection with Aeromonas hydrophila. Furthermore, we studied the iron binding properties of recombinant Tf. The full-length M. amblycephala Tf complementary DNA (cDNA) (GenBank accession no.: KX698308) of 2245 bp was cloned and contained a 1953 bp open reading frame (ORF) encoding 650 amino acid residues and flanked by a 68 bp 5′ and a 204 bp 3′ untranslated regions (UTR). Predicted conservative structure illustrated that M. amblycephala Tf consisted of two conservative Tf domains. Amino acid sequence alignment revealed that M. amblycephala Tf had high similarity with that of cyprinids deposited in Genbank, and phylogenetic analysis showed that M. amblycephala Tf clustered with Ctenopharyngodon idella and Hypophthalmichthys molitrix. Tissue expression pattern analyses demonstrated that the liver was the main Tf mRNA expressing organ, being significantly higher than other tissues (p < 0.05). In the liver, Tf mRNA expression in fish artificially injected with the pathogenic bacteria A. hydrophila was significantly upregulated, reaching a peak at 12 h post injection (hpi) and then decreasing afterward. The expression in FeCl3-injected fish showed a similar tendency, but reached a peak at 8 hpi. Meanwhile, fish serum iron significantly decreased following A. hydrophila injection, but increased to peak at 4 hpi and then decreased in FeCl3-injected fish. The recombinant M. amblycephala Tf showed iron binding capacity using CAS analysis. These results are helpful to understand the structure and regulation of expression of Tf, as well as the specific function of Tf for both immune responses and iron homeostasis.  相似文献   

9.
Several outbreaks of Streptococcus agalactiae infection of bighead carp (Aristichthys nobilis) were observed in China. The molecular epidemiology and pathogenicity of S. agalactiae in bighead carp and tilapia (Oreochromis sp.) is poorly understood. In the present study, we identified S. agalactiae strains isolated from diseased bighead carp using the API 20 Strep kit and 16S rDNA sequencing and determined whether these strains came from tilapia. Of the 46 identified S. agalactiae strains, 24 strains were successfully isolated from diseased bighead carps, 20 S. agalactiae strains were isolated from tilapia, and two S. agalactiae strains were isolated from tiger frog (Hoplobatrachus chinensis). The results of molecular typing, including multilocus sequence typing, molecular serotyping, surface protein gene detection, and virulence-related gene detection showed that the 44 strains from bighead carp and tilapia were highly similar, whereas different from tiger frog GBS strains. Remarkably, the bighead carp strain Hn1404 showed high virulence in bighead carp and zebrafish. Moreover, this strain was pathogenic to Nile tilapia (Oreochromis niloticus). In addition, comparative genomic analysis showed that isolate Hn1404 had a close relationship with the bighead carp and tilapia S. agalactiae strains. All the analyses of the genetic characteristics of bighead carp and tilapia strains showed that tilapia S. agalactiae strains could be transmitted to other fish species such as bighead carp.  相似文献   

10.
Multidomain proapoptotic Bcl-2-associated X (Bax) protein is an essential effector responsible for mitochondrial outer membrane permeabilization, resulting in cell death via apoptosis. In this study, two Bax genes of grass carp (Ctenopharyngodon idellus), designated as CiBax1 and CiBax2, were isolated and analyzed. The obtained CiBax1 cDNA is 2058 bp long, with a 579 bp open reading frame (ORF) coding a protein of 192 amino acid residues. The full-length cDNA of CiBax2 is 1161 bp, with a 618 bp ORF coding 205 amino acids. Both CiBax1 and CiBax2 are typical members of Bcl-2 family containing conserved Bcl and C-terminal domains, and they share conserved synteny with zebrafish Bax genes despite the grass carp Bax mapping to different linkage groups. Phylogenetic analysis showed that CiBax1 was clustered with Bax from most teleost fish, and CiBax2 was close to Bax2 from teleost fish but far separated from that of Salmo salar. Quantitative real-time PCR analysis revealed broad expression of CiBax1 and CiBax2 in tissues from healthy grass carp, but the relative expression level differed. The mRNA expression of CiBax1 and CiBax2 was both upregulated significantly and peaked in all examined tissues at days 5 or 6 post-infection with grass carp reovirus. Subcellular localization indicated that CiBax1 protein was localized in both nucleus and cytosol, while CiBax2 protein only in cytosol. Moreover, CiBax2, but not CiBax1 was colocalized with mitochondrion under normal condition. Taken together, the findings would be helpful for further understanding of the function of Bax in teleost fish.  相似文献   

11.
In the present study, cellulase, protease, lipase and amylase activities were performed to investigate the effects of Lactococcus lactis subsp. lactis CF4MRS bioencapsulation of Artemia franciscana. Our results show that cellulase activities (total cellulase—FPase activity, exoglucanase and endoglucanase—CMCase activity) were significantly higher (P < 0.05) in A. franciscana tissue homogenates compared to those in the control group after 8 h of L. lactic bioencapsulation. Notably, an exception case was found in β-D-glucosidase activity, whereby the cellulase activity was not significantly different (P > 0.05) compared to the control group. Administrations of L. lactis at cell concentration of 108 CFU mL?1 showed considerable improvement of other important enzymatic activities such as amylase, protease and lipase in A. franciscana. The amylase/protease ratio in probiotic-treated A. franciscana was recorded at 0.343, approximately two times higher than those without probiotic administration (0.184). In contrary, amylase/lipase ratio showed half of a reduction (0.330) in L. lactis-administrated A. franciscana compared to the control (0.614). Our study suggests that important digestive enzymes, e.g., cellulase, amylase, protease and lipase, can be enhanced through bioencapsulation of A. franciscana with L. lactis subsp. lactis, which could in turn lead to further stimulation of endogenous enzymes in the fish and shrimp larvae.  相似文献   

12.
Larval rearing is affected by a wide range of microorganisms that thrive in larviculture systems. Some seaweed species have metabolites capable of reducing the bacterial load. However, no studies have yet tested whether including seaweed metabolites on larval rearing systems has any effects on the larvae development. This work assessed the development of Sparus aurata larvae fed preys treated with an Asparagopsis armata product. Live prey, Brachionus spp. and Artemia sp., were immersed in a solution containing 0.5% of a commercial extract of A. armata (Ysaline 100, YSA) for 30 min, before being fed to seabream larvae (n = 4 each). In the control, the live feed was immersed in clear water. Larval parameters such as growth, survival, digestive capacity (structural-histology and functional-enzymatic activity), stress level (cortisol content), non-specific immune response (lysozyme activity), anti-bacterial activity (disc-diffusion assay) and microbiota quantification (fish larvae gut and rearing water) were monitored. Fish larvae digestive capacity, stress level and non-specific immune response were not affected by the use of YSA. The number of Vibrionaceae was significantly reduced both in water and larval gut when using YSA. Growth was enhanced for YSA treatment, but higher mortality was also observed, especially until 10 days after hatching (DAH). The mortality peak observed at 8 DAH for both treatments, but higher for YSA, indicates larval higher susceptibility at this development stage, suggesting that lower concentrations of YSA should be used until 10 DAH. The application of YSA after 10 DAH onwards promotes a safer rearing environment.  相似文献   

13.
Jatropha seed cake (JSC) is an excellent source of protein but does contain some antinutritional factors (ANF) that can act as toxins and thus negatively affect the growth and health status of fish. While this can limit the use of JSC, detoxified Jatropha protein isolate (DJPI) may be a better option. An 8-week study was performed to evaluate dietary DJPI to common carp Cyprinus carpio. Five iso-nitrogenous diets (crude protein of 38%) were formulated that consisted of a C ontrol (fish meal (FM) based protein), J 50 or J 75 (50 and 75% of FM protein replaced by DJPI), and S 50 or S 75 (50 and 75% of FM protein replaced by soy protein isolate, SPI) and fed to triplicate groups of 75 carp fingerlings (75; av. wt. ± SD; 11.4 ± 0.25 g). The growth, feeding efficiencies, digestibility, plasma biochemistry, and intestinal enzymes were measured. Results showed that growth performance of fish fed the S 75- or DJPI-based diets were not significantly different from those fed the C ontrol diet, while carp fed the S 50 had significantly better growth than the J 75 diet. Fish fed the J 75 diet had significantly lower protein and lipid digestibility as well as significantly lower intestinal amylase and protease activities than all other groups. However, all plant protein-based diets led to significantly higher crude protein, crude lipid, and gross energy in the body of common carp compared to the control treatment. Plasma cholesterol and creatinine significantly decreased in the plant protein fed groups, although plasma triglyceride as well as the red blood cells count, hematocrit, albumin, globulin, total plasma protein, and lysozyme activity were higher in plant protein fed groups compared to FM fed group. White blood cells, hemoglobulin concentration, alkaline phosphatase and alanine transaminase activities, and glucose level in blood did not differ significantly among treatments. The results suggest that the DJPI is non-toxic to carp and can be used to replace FM in the diets of common carp up to 75%, but further research to potentially reduce some inherent ANF within this protein source, such as non-starch polysaccharides, may improve nutrient utilization.  相似文献   

14.
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15.
Myoglobin (Mb) is an oxygen-binding hemoprotein that was once thought to be exclusively expressed in oxidative myocytes of skeletal and cardiac muscle where it serves in oxygen storage and facilitates intracellular oxygen diffusion. In this study, we cloned the coding sequence of the Mb gene from four species, representing three groups, of the schizothoracine fish endemic to the Qinghai-Tibetan Plateau (QTP), then conducted molecular evolution analyses. We also investigated tissue expression patterns of Mb and the expression response to moderate and severe hypoxia at the mRNA and protein levels in a representative of the highly specialized schizothoracine fish species, Schizopygopsis pylzovi. Molecular evolution analyses showed that Mb from the highly specialized schizothoracine fish have undergone positive selection and one positively selected residue (81L) was identified, which is located in the F helix, close to or in contact with the heme. We present tentative evidence that the Mb duplication event occurred in the ancestor of the schizothoracine and Cyprininae fish (common carp and goldfish), and that the Mb2 paralog was subsequently lost in the schizothoracine fish. In S. pylzovi, Mb mRNA is expressed in various tissues with the exception of the intestine and gill, but all such tissues, including the liver, muscle, kidney, brain, eye, and skin, expressed very low levels of Mb mRNA (<?8.0%) relative to that of the heart. The trace levels of Mb expression in non-muscle tissues are perhaps the major reason why non-muscle Mb remained undiscovered for so long. The expression response of the Mb gene to hypoxia at the mRNA and protein levels was strikingly different in S. pylzovi compared to that found in the common carp, medaka, zebrafish, and goldfish, suggesting that the hypoxia response of Mb in fish may be species and tissue-specific. Notably, severe hypoxia induced significant expression of Mb at the mRNA and protein levels in the S. pylzovi heart, which suggests Mb has a major role in the supply of oxygen to the heart of Tibetan Plateau fish.  相似文献   

16.
Long-chain unsaturated n-3 fatty acids are of remarkable significance in human nutrition. They have antiatherosclerotic efficacy and other beneficial health effects too. Aquaculture fish, e.g. cyprinids, such as silver carp (Hypophthalmichthys molitrix), bighead carp (Aristichthys nobilis), common carp (Cyprinus carpio), tench (Tinca tinca), and salmonids like Atlantic salmon (Salmo salar) and rainbow trout (Oncorhynchus mykiss) as well as European catfish (Silurus glanis), Baltic whitefish (Coregonus maraena), European seabass (Dicentrarchus labrax), gilthead seabream (Sparus aurata), and Nile tilapia (Oreochromis niloticus), are rich in these fatty acids. When fed on suitable diets, the fatty acid composition of cultured fish can be influenced advantageously. Several clinical tests proved the effectiveness of the consumption of farmed fish in promoting human health. Thus, aquaculture fish can be recommended as wholesome food.  相似文献   

17.
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18.
In the current study, laboratory evaluations were made to assess the immunomodulatory effect of cypermethrin on fingerlings of common carp (Cyprinus carpio L.). Results showed that 96-h LC50 of cypermethrin in common carp was estimated at 0.85 μg/L. Fish were exposed for 21 days to cypermethrin at three sub-lethal concentrations of 0.042, 0.085, and 0.17 μg/L that represented 5, 10, and 20%, respectively, of the 96-h LC50 of the pesticide for this fish species. Blood samples were taken after 7, 14, and 21 days of exposure. Immunological indices and resistance against bacterial infection were determined. Compared to the control group, the fish exposed to cypermethrin showed a significant increase in neutrophil ratio but exhibited a significant decrease in leukocyte number and lymphocyte ratio in treatments exposed to 0.17 and/or 0.085 μg/L after 21 days of exposure (p < 0.05). Serum protein level was significantly decreased in group exposed to 0.17 μg/L on day 14 and also in groups exposed to 0.085 and 0.17 μg/L on day 21 (p < 0.05). Immunoglobulin value was significantly reduced in groups exposed to 0.085 and 0.17 μg/L after 21 days of exposure (p < 0.05). Serum lysozyme activity and phagocytic activity were significantly decreased following exposure to 0.17 μg/L determined on days 14 and 21, post-exposure (p < 0.05). Mortality rate following the challenge with Aeromonas hydrophila significantly increased in fish exposed to 0.17 μg/L of cypermethrin. Overall, the present results indicate severe immunotoxicological effects of cypermethrin in common carp. Therefore, the use of cypermethrin in the proximities of common carp farms should be carefully considered.  相似文献   

19.
Administration of probiotic candidates in fish has generally been shown as a useful strategy to improve growth performance, survival, digestive enzyme activity, and gut microbiota. Unfortunately, the sero-immunological responses of different fish to different probiotic candidates are poorly understood. The present study assessed the effect of Pediococcus acidilactici as a probiotic on the biochemical and immunological parameters of beluga. Fish (248.32?±?10.21 g) were fed a control diet (without P. acidilactici( and three different doses of P. acidilactici-supplemented diets (107, 108, and 109 CFUg?1 diets) for 8 weeks. On week 8, blood and serum were sampled. Dose-dependent increase of immunological parameters (respiratory burst activity, lysozyme content, serum antibacterial activity, and total immunoglobulin) and biochemical parameters (total protein and albumin levels) was observed. However, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were significantly increased in the juvenile beluga fed by 109 CFUg?1 P. acidilactici-supplemented diet compared to the other groups. Based on the results of this evaluation, it is reasonable to conclude that the inclusion of P. acidilactici as probiotic in diets for juvenile beluga improves the sero-immunological parameters of the fish and should be considered by farmers as a strategy to improve fish health.  相似文献   

20.
Heat stress is one of the major environmental concerns in global warming regime and rising temperature has resulted in mass mortalities of animals including fishes. Therefore, strategies for high temperature stress tolerance and ameliorating the effects of heat stress are being looked for. In an earlier study, we reported that Nrf-2 (nuclear factor E2-related factor 2) mediated upregulation of antioxidative enzymes and heat shock proteins (Hsps) provide survivability to fish under heat stress. In this study, we have evaluated the ameliorative potential of dietary curcumin, a potential Nrf-2 inducer in heat stressed cyprinid Puntius sophore. Fishes were fed with diet supplemented with 0.5, 1.0, and 1.5% curcumin at the rate 2% of body weight daily in three separate groups (n = 40 in each group) for 60 days. Fishes fed with basal diet (without curcumin) served as the control (n = 40). Critical thermal maxima (CTmax) was determined for all the groups (n = 10, in duplicates) after the feeding trial. Significant increase in the CTmax was observed in the group fed with 1.5% curcumin- supplemented fishes whereas it remained similar in groups fed with 0.5%, and 1% curcumin-supplemented diet, as compared to control. To understand the molecular mechanism of elevated thermotolerance in the 1.5% curcumin supplemented group, fishes were given a sub-lethal heat shock treatment (36 °C) for 6 h and expression analysis of nrf-2, keap-1, sod, catalase, gpx, and hsp27, hsp60, hsp70, hsp90, and hsp110 was carried out using RT-PCR. In the gill, expression of nrf-2, sod, catalase, gpx, and hsp60, hsp70, hsp90, and hsp110 was found to be elevated in the 1.5% curcumin-fed heat-shocked group compared to control and the basal diet-fed, heat-shocked fishes. Similarly, in the liver, upregulation in expression of nrf-2, sod, catalase, and hsp70 and hsp110 was observed in 1.5% curcumin supplemented and heat shocked group. Thus, this study showed that supplementation of curcumin augments tolerance to high temperature stress in P. sophore that could be attributed to nrf-2-induced upregulation of antioxidative enzymes sod, catalase, gpx, and the hsps.  相似文献   

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