Intraperitoneal injection of genistein affects the distribution and metabolism of cholesterol in female yellow catfish Tachysurus fulvidraco.

Genistein is an abundant phytoestrogen in soybean. This study aimed to determine the effects of genistein on cholesterol distribution and metabolism in female yellow catfish. Three hundred fish (49.2 ± 1.4 g) were randomly divided into five treatments and received intraperitoneal injections as follows: (1) blank, no injection; (2) control, vehicle only; (3) E2, 17ß-estradiol at 10 µg·g-1 body weight; (4) low genistein doses, genistein at 10 µg·g-1 body weight; (5) high genistein doses, genistein at 100 µg·g-1 body weight. Both high and low genistein doses significantly reduced (p < 0.05) serum TC and LDL-C 24 h after injection. Moreover, the high genistein doses significantly reduced (p < 0.05) serum HDL-C. Both high and low doses of genistein significantly increased (p < 0.05) hepatic TC. Only high genistein doses significantly increased (p < 0.05) ovary TC. In the liver, both high and low genistein doses significantly increased (p < 0.05) protein and mRNA expression of ldlr. Meanwhile, high genistein doses significantly decreased (p < 0.05) mRNA expression of hmgcr. In ovary tissue, high genistein doses significantly decreased (p < 0.05) mRNA expression of cyp11a1. These results suggested that genistein affected the cholesterol distribution in female yellow catfish. Both high and low doses of genistein reduced cholesterol content in blood and increased its content in the liver by increasing the uptake of blood cholesterol. Meanwhile, high genistein doses may inhibit hepatic cholesterol synthesis. Additionally, high genistein doses could increase cholesterol transfer from serum into the ovary and disturb cholesterol conversion to pregnenolone.

Hematological and immunological responses in the African catfish Clarias gairepinus exposed to sublethal concentrations of herbicide Ronstar®.

The aim of the study was to investigate the effects of sublethal concentrations (0.3, 0.6 and 1.2 mg L-1) of the herbicide Ronstar on the hematology and some immune parameters in Clarias gariepinus juvenile (mean weight and length 58.72 ± 2.46 g and 27.60 ± 1.62 cm, respectively). The hematological and some immune parameters were studied for 21 days in a static renewal bioassay system in which the water and the herbicide were changed daily. The erythrocyte count, hemoglobin concentration (Hb), and packed cell volume (PCV) were significantly (p < 0.05) reduced in the treatment groups. When compared with the control, there were significant (p < 0.05) leucocytosis, lymphocytosis, neutropenia and monocytopenia in the treatment groups. Both the mean corpuscular hemoglobin (MCH) and mean corpuscular volume (MCV) were reduced ((p < 0.05) in the Ronstar-exposed fish. The result showed that the treated fish suffered hypochromic microcytic anemia. The total immunoglobulin and phagocytic indices (phagocytic capacity and phagocytic index) were significantly (p < 0.05) reduced in the treatment groups. while the respiratory burst was significantly (p < 0.05) increased in the treatment groups. The result showed that exposure to Ronstar had adverse effects on the hematology and immunocompetency of the fish.

Acrylamide-induced hematotoxicity, oxidative stress, and DNA damage in liver, kidney, and brain of catfish (Clarias gariepinus).

This study was carried out to explore the possible deleterious impacts of acrylamide (ACR) on catfish (Clarias gariepinus). The estimation of mortalities, the examination of the clinical picture, the evaluation of blood parameters, oxidative stress, DNA damage, and the histopathological picture were performed in the liver, kidney, and brain samples of the experimentally ACR-exposed catfish. The 96 hours LC50 value was estimated to be 133 mg/L by the hydrostatic method. Fish were reared in water containing four different concentrations of ACR as follows: 20%, 40%, 60%, and 80% of the estimated LC50 for 2 weeks. Abnormal behavioral, clinical, and postmortem responses were depicted. The anemic response including significant decreases in red blood cells, hemoglobin, and packed cell volume following the ascending concentrations of ACR were recorded. The malondialdehyde was significantly increased, whereas reduced glutathione level, superoxide dismutase, and total antioxidant capacity were significantly decreased. The DNA fragmentation assay illustrated a clear laddering pattern in all the tested organs. Notably, the brain was the most influenced organ. It is presumed that ACR contamination showed adverse impacts on the catfish.

Titanium dioxide nanoparticles-induced cytogenotoxicity and alterations in haematological indices of Clarias gariepinus (Burchell, 1822).

The application of titanium dioxide (TiO2) nanoparticles (NPs) in the manufacturing of consumer products has increased tremendously and with the potential to induce deleterious effects on aquatic biota. There have been reports on metal oxide NP toxicity in aquatic organisms, however, information on cytotoxicity and genotoxicity of TiO2 NPs on the African catfish, Clarias gariepinus, is scarce. In this study, we investigated the genotoxicity and haematotoxicity of TiO2 NPs in C. gariepinus using the micronucleus (MN) assay and haematological analysis, respectively. Juvenile C. gariepinus were exposed to 6.25, 12.5, 25.0, 50.0 and 100.0 mg L-1 concentrations of TiO2 NPs for 7 and 28 days. Benzene (0.05 mL L-1) and dechlorinated tap water were used as positive and negative controls, respectively. Data of the MN showed a significant (p < 0.05) concentration-dependent increase in the frequency of MN at both exposure periods in comparison to negative control. Red blood cells, haematocrit, platelets and heterophils significantly reduced with an increased mean corpuscular haemoglobin concentration and lymphocytes at the 7-day exposure period, while in the 28-day exposure period, mean cell volume, mean corpuscular haemoglobin and lymphocytes had a significant increase in comparison with the negative control. This study indicates that TiO2 NPs induced cytogenetic and haematological alterations in C. gariepinus and is of relevance in biodiversity and aquatic health management.

Impact of herbicide pretilachlor on reproductive physiology of walking catfish, Clarias batrachus (Linnaeus).

Herbicide pretilachlor is widely used in paddy fields to control annual weeds. The present study has been carried out in walking catfish, Clarias batrachus, to evaluate the impact of herbicide pretilachlor on reproductive physiology after chronic exposure. Based on the median lethal concentration value (96 h), fish were exposed to three nominal test concentrations of pretilachlor ((SL-I (1/20th LC50), SLII (1/15th LC50), and SL-III (1/10th LC50)) for 30, 45, and 60 days after which plasma sex steroid profile, plasma vitellogenin concentration, and gonadal aromatase activity were analyzed in both sexes. Plasma concentration of testosterone decreases in herbicide-exposed male fish. Significant increase in plasma 17ß-estradiol, plasma vitellogenin concentration, and gonadal aromatase activity were observed in herbicide-exposed male fish. All these alterations in reproductive parameters in male fish are dependent on concentration and exposure duration of herbicide. On the other hand, significant decrease in plasma concentration of testosterone was observed in female fish which was also dependent on concentration and exposure duration of herbicide. No significant changes in plasma 17ß-estradiol concentrations, plasma vitellogenin concentration, and gonadal aromatase activity were observed in female fish. Above findings clearly suggested that herbicide pretilachlor acts as endocrine disruptor in fish and affects overall reproductive physiology of fish, but its ability to induce reproductive toxicity in male and female differs considerably.

Toxicological response of silver catfish (Rhamdia quelen) after acute exposure to a commercial insecticide containing thiamethoxam.

This study assessed the hematological, enzymatic and osmoregulatory responses of silver catfish (Rhamdia quelen) exposed to sublethal concentrations (1.125 and 3.750 µg/L) of a commercial thiamethoxam-containing insecticide used on rice crops. Groups of 6 fish per tank (in triplicate, n = 3, total 54 fish) were exposed for up to 96 h to different concentrations of the compound. After this period, fish were placed in clean water for 48 h. Two fish from each tank (6 per treatment) that had been exposed to the insecticide for 24 h were anesthetized with eugenol and blood was collected to evaluate hematological and biochemical parameters. Blood, liver and muscle were collected for determination of metabolic parameters, plasma cortisol, Cl-, Na+ and K+ levels and H+-ATPase and Na+/K+-ATPase activity in the gill. H+-ATPase activity was higher in fish exposed to 1.125 µg/L insecticide at 24 h compared to control (0.0 µg/L). Differences in cortisol levels were evidenced throughout the experimental period. These results indicated that exposure to the insecticide changed the hematological, biochemical and metabolic profile of the animals, suggesting concern about environmental safety. Therefore, we discourage the use of this pesticide in areas that come into contact with water bodies inhabited by fish.

Hematological analysis of Ctenopharyngodon idella, Megalobrama amblycephala and Pelteobagrus fulvidraco: Morphology, ultrastructure, cytochemistry and quantification of peripheral blood cells.

The grass carp (Ctenopharyngodon idella), blunt snout bream (Megalobrama amblycephala) and yellow catfish (Pelteobagrus fulvidraco) are economically important fishes in China. Fish hematological features, especially the type and number of peripheral blood cells, are crucial for the evaluation of fish health and the diagnosis of fish diseases. Since the automatic blood cell count equipment for human is not suitable for fishes, the manual method is critical in the quantification of fish blood cells. To make sense of the comparison and interpretation of the blood cell count studies in different articles, the standardization of blood cell classification is necessary. In this study, erythrocytes (red blood cell, RBC), thrombocytes (TC) and leucocytes (i.e. white blood cells, WBC, including lymphocytes, neutrophils and monocytes) were well distinguished in blood smears with Giemsa staining and confirmed by transmission electron microscopy. RBC, TC and WBC were directly counted with an improved Neubauer counting chamber in a modified diluting solution. The differential leucocyte count (DLC) was carried out in blood smears. In view of the labeling characteristics of peroxidase (PO) positivity in neutrophils and non-specific esterase (α-ANAE) positivity in monocytes, PO positive cell percentage and α-ANAE positive cell percentage were also determined in cytochemistry staining smears. No difference was found for the percentages of neutrophils and monocytes between Giemsa staining and cytochemistry staining. The standardized classification, normal count ranges and sizes of the peripheral blood cells by the present systemic studies will provide useful references for monitoring the health status of grass carp, blunt snout bream and yellow catfish.

Photo-thermal regulation of neuropeptide Y (NPY) expression in ovarian follicles and ovarian activity of the catfish, Clarias batrachus.

Authors have recently reported a gradual increase in neuropeptide Y expression in the ovarian follicles of Clarias batrachus with the progression of oogenesis, coinciding with increasing photoperiod and temperature. This indicates the involvement of photoperiod and temperature in controlling NPY expression. Therefore, a study was designed to investigate the role of photoperiod and temperature in regulation of NPY expression in ovarian follicles. The catfish were exposed to different photo-thermal regimes during the late-quiescence and late-recrudescence phases for one month, and the expression of NPY was analyzed along with other ovarian activities. Though the exposure of catfish to long photoperiod induced a marginal increase (1.5 fold) in NPY expression in follicular cells, the high temperature stimulated its expression more effectively (6-10 fold), irrespective of photoperiodic exposures. Exposure to long photoperiod and high temperature together induced NPY expression maximally in granulosa and thecal cells of fully grown oocytes, but exposure to low temperature decreased its expression significantly. The oogenic and steroidogenic activities were also promoted simultaneously after the exposure to high temperature and long photoperiod alone or in combination. However, the low temperature exposure suppressed the ovarian activities leading to atresia of advanced follicles. Thus it is suggested that photoperiod and temperature both affect NPY expression and ovarian recrudescence in fish but the influences of temperature seem to be more prominent.

Metabolic responses to dietary carbohydrate/lipids ratios in neotropical hybrid catfish (♂Pseudoplatystoma corruscans×♀Pseudoplatystoma fasciatum).

The purpose of this study was to assess the effect of different carbohydrate and lipid (CHO/L) ratios on the performance and energy metabolism of hybrid catfish (♂Pseudoplatystoma corruscans × â™€ Pseudoplatystoma fasciatum). One hundred and sixty-eight fish (104.9±16.5 g BW) were distributed into 24 100-L tanks. The experiment was performed using a randomised block design with four CHO/L ratios (0.45, 1.00, 1.66 and 2.85) and six replications. Growth performance, protein content, glucose and triglycerides in plasma, muscle and liver, and the hepatic activity of the malic and glucose-6-phosphate dehydrogenase (G6PD) enzymes were measured after 60 feeding days. No significant differences were observed in growth performance, protein and triglycerides of plasma and muscle, hepatic protein or malic enzyme activity. CHO/L: 2.85 provided the highest plasma and liver glucose, while CHO/L: 0.45 showed high liver triglycerides. A linear effect was found for the hepatic activity of G6PD and dietary starch levels (R2=0.93). The hepatic activity of G6PD was greater in CHO/L=2.85 than for CHO/L: 0.45. In conclusion, the limit of dietary starch inclusion and lipids were 15% and 9.00%, respectively (CHO/L: 1.66), and this level did not affect the energy metabolism of the juvenile hybrid catfish.

Physiological and metabolic responses of juvenile Lophiosilurus alexandri catfish to air exposure.

The present study aimed to evaluate the physiological and metabolic stress responses of juvenile Lophiosilurus alexandri submitted to an air exposure test. The subjects consisted of 72 juveniles. Blood samples were taken at: 0 h-fish not exposed to air; 0.5 h-fish shortly after exposure to air for 30 min (prior to returning to the tank); 1.5 h (90 min), 24, 48, and 96 h after the initiation of exposure to air for 30 min. After 96 h, survivorship was 100%. Cortisol and glucose levels were higher at 0.5 h, returning to baseline at 48 and 24 h, respectively. Lactate dehydrogenase levels were highest at 1.5 h after exposure to air, returning to normal values in 24 h. Several changes were recorded in gasometric blood values and electrolytes. With regard to hematology and blood chemistry, exposure to air did not affect globular volume and AST throughout the 96 h of the experiment. The values for alkaline phosphatase were highest at 0, 1.5, and 24 h. Total protein was similar between 0 and 1.5 h and lowest at 96 h, while ALT was highest at 0.5 h. Leukocytes were highest at 0.5, 1.5, 48, and 96 h, while erythrocytes were highest at 96 h. After 96 h, juvenile L. alexandri were able to reestablish the main indicators of stress (cortisol, glucose and lactate dehydrogenase), while other indicators (hematological, biochemical, and gasometric) exhibited compensatory variation for normal physiological re-establishment.

Water pH limits extracellular but not intracellular pH compensation in the CO2-tolerant freshwater fish Pangasianodon hypophthalmus.

Preferentially regulating intracellular pH (pHi) confers exceptional CO2 tolerance on fish, but is often associated with reductions in extracellular pH (pHe) compensation. It is unknown whether these reductions are due to intrinsically lower capacities for pHe compensation, hypercarbia-induced reductions in water pH or other factors. To test how water pH affects capacities and strategies for pH compensation, we exposed the CO2-tolerant fish Pangasianodon hypophthalmus to 3 kPa PCO2  for 20 h at an ecologically relevant water pH of 4.5 or 5.8. Brain, heart and liver pHi was preferentially regulated in both treatments. However, blood pHe compensation was severely reduced at water pH 4.5 but not 5.8. This suggests that low water pH limits acute pHe but not pHi compensation in fishes preferentially regulating pHi Hypercarbia-induced reductions in water pH might therefore underlie the unexplained reductions to pHe compensation in fishes preferentially regulating pHi, and may increase selection for preferential pHi regulation.

Effect of Agaricus bisporus enriched diet on growth, hematology, and immune protection in Clarias gariepinus against Flavobacterium columnare.

The purpose of the present study was to find out the effect of dietary enriched button mushroom, Agaricus bisporus at 1%, 5%, and 10% levels on growth performance, hematology, nonspecific immune responses, and disease resistance in catfish, Clarias gariepinus against Flavobacterium columnare for a period of four weeks. The percentage weight gain and specific growth rate (SGR) were higher in the infected fish fed with 5% A. bisporus enriched diet than with 1% and 10% diets. The red blood cell (RBC), white blood cell (WBC), hematocrit (PCV), and haemoglobin (Hb) values are similar (p > .05) among the experimental groups at the end of fourth week. The phagocytic activity, complement activity, and lysozyme activity were significantly enhanced in the infected fish fed with 5% A. bisporus diet during the experimental period; however, it was significantly enhanced with 10% A. bisporus enriched diet only on weeks 2 and 4. On the other hand, the respiratory burst (RB) activity increased significantly in the infected fish fed with 5% and 10% A. bisporus enriched diets. When fed with 5% A. bisporus diet the cumulative mortality was very low (10%), followed by a high survival rate (89%) in the infected fish; nevertheless, the cumulative mortality was 25% and 20% while it was 74% and 79% when fed with 1% and 10% enriched diets. The present study recommends a dietary supplement of A. bisporus at 5% or 10% level to achieve better growth without side effect, and enhance the nonspecific immune system that prevent mortalities from F. columnare infection in C. gariepinus.

Effects of acute ammonia toxicity on oxidative stress, immune response and apoptosis of juvenile yellow catfish Pelteobagrus fulvidraco and the mitigation of exogenous taurine.

Ammonia can easily form in intensive culture systems due to ammonification of uneaten food and animal excretion, which usually brings detrimental health effects to fish. However, little information is available on the mechanisms of the detrimental effects of ammonia stress and mitigate means in fish. In this study, the four experimental groups were carried out to test the response of yellow catfish to ammonia toxicity and their mitigation through taurine: group 1 was injected with NaCl, group 2 was injected with ammonium acetate, group 3 was injected with ammonium acetate and taurine, and group 4 was injected taurine. The results showed that ammonia poisoning could induce ammonia, glutamine, glutamate and malondialdehyde accumulation, and subsequently lead to blood deterioration (red blood cell, hemoglobin and serum biochemical index reduced), oxidative stress (superoxide dismutase and catalase activities declined) and immunosuppression (lysozyme, 50% hemolytic complement, total immunoglobulin, phagocytic index and respiratory burst reduced), but the exogenous taurine could mitigate the adverse effect of ammonia poisoning. In addition, ammonia poisoning could induce up-regulation of antioxidant enzymes (Cu/Zn-SOD, CAT, GPx and GR), inflammatory cytokines (TNF, IL-1 and IL-8) and apoptosis (p53, Bax, caspase 3 and caspase 9) genes transcription, suggesting that cell apoptotic and inflammation may relate to oxidative stress. This result will be helpful to understand the mechanism of aquatic toxicology induced by ammonia in fish.

Seasonal ovarian immunolocalization of neuropeptide Y and its role in steriodogenesis in Asian catfish, Clarias batrachus.

The present study was undertaken to examine the cellular localization and potential steroidogenic role of neuropeptide Y (NPY) in the ovary of the freshwater catfish, Clarias batrachus. NPY-immunoreaction was observed in the follicular cells (granulosa and thecal cells) in the growing ovarian follicles, and the intensity of staining increased steadily from the initiation of follicular development until follicles were fully grown. Thereafter as follicles matured the stain intensity decreased. Positive correlations were found between NPY expression and the ovarian levels of 17ß-estradiol, testosterone, and activities of 3ß-hydroxysteroid dehydrogenase (3ß-HSD) and 17ß-hydroxysteroid dehydrogenase (17ß-HSD) in the ovary. In vitro NPY treatment stimulated the production of the two steroids and the activities of two enzymes. This is the first report of NPY immunoreactivity at the cellular level in the fish ovary and implicates this orexigenic peptide in the modulation of ovarian steroidogenesis.

Expression profiling of c-kit and its impact after esiRNA silencing during gonadal development in catfish.

Receptor, c-Kit is a member of a family of growth factor receptors that have tyrosine kinase activity, and are involved in the transduction of growth regulatory signals across plasma membrane by activation of its ligand, kitl/scf. The present study analyzed mRNA and protein expression profiles of c-kit in the gonads of catfish, Clarias gariepinus, using real time PCR, in situ hybridization and immunohistochemistry. Tissue distribution analysis revealed higher expression mainly in the catfish gonads. Ontogeny studies showed minimal expression during early developmental stages and highest during 50-75 days post hatch, and the dimorphic expression in gonads decreased gradually till adulthood, which might suggest an important role for this gene around later stages of sex differentiation and gonadal development. Expression of c-kit was analyzed at various phases of gonadal cycle in both male and female, which showed minimal expression during the resting phase, and higher expression during the pre-spawning phase in male compared to females. In vitro and in vivo induction using human chorionic gonadotropin elevated the expression of c-kit indicating the regulatory influence of hypothalamo-hypophyseal axis. In vivo transient gene silencing using c-kit-esiRNA in adult catfish during gonadal recrudescence showed a decrease in c-kit expression, which affected the expression levels of germ cell meiotic marker sycp3, as well as several factors and steroidogenic enzyme genes that are involved in germ cell development. Decrease in the levels of 11-ketotestosterone and testosterone in serum were also observed after esiRNA silencing. The findings suggests that c-kit has an important role in the process of germ cell proliferation, development and maturation during gonadal development and recrudescence in catfish.

Effects on haematological and serum biochemical parameters of Pangasianodon hypophthalmus to an experimental infection of Thaparocleidus sp. (Monogenea: dactylogyridae).

Monogenea (gill parasite) is a major problem in aquaculture that reduces the growth of cultured fish and adversely affects the economy. The present study was performed to evaluate the impact of various degrees of Thaparocleidus sp. (dactylogyrids, monogenean) infestation on haematological and serum biochemical parameters of Pangasianodon hypophthalmus. A standard cohabitation study, following complete randomized design in triplicate, was conducted to obtain low, moderate and high degrees of infestation in P. hypophthalmus along with the control (uninfested) group. Blood and serum were studied for haematological (total erythrocyte count (TEC), haemoglobin (Hb), packed cell volume (PCV), total leucocyte count (TLC) and indices viz. mean cell volume (MCV), mean cell haemoglobin (MCH), mean cell haemoglobin concentration (MCHC) and erythrocyte osmolarity brittleness (EOB)) and serum biochemical parameters (serum glutamate oxaloacetate transaminase (SGOT), serum glutamate pyruvate transaminase (SGPT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), lactate, total bilirubin and creatinine. Significant (p < 0.05) increase in TEC, Hb, TLC, EOB, SGOT, SGPT, LDH, lactate, bilirubin, and creatinine were noticed in moderate to high monogenean-infested group in comparison to the control group. However, significant (p < 0.05) reduction in MCH, and MCV and no difference (P > 0.05) in PCV were noticed in high degree parasitized group in comparison to the control group. The results of altered haematological and serum biochemical parameters in various degrees of monogenean-infested groups signify the density dependent physiological responses and changes in cells of the blood. The data of serum enzymes in the present study would be valuable for assessing the health status of the host and facilitate as a potential biomarker in relation to various degrees of monogenean infestation.

Modulatory effects of green tea extract against the hepatotoxic effects of 4-nonylphenol in catfish (Clarias gariepinus).

The antioxidant role of the green tea (Camellia sinensis) extract (GTE) was examined to remedy the toxic effects of (0.2mgl-1) 4-nonylphenol(4-NP). Biochemical parameters, antioxidant enzymes, liver lipid peroxidation (LPO), DNA fragmentation, and apoptosis as well as histopathology of liver of African catfish Clarias gariepinus were considered. Catfishes were divided into four groups: first group (control), second group (0.2mgl-1 of 4-NP), third group (0.2mgl-1of 4-NP +100mg GTE l-1water), and fourth group (0.2mgl-1 of 4-NP +200mg GTE l-1water). The results showed that significant increments of serum glucose, AST, ALT, total protein, total lipids, cholesterol, G6PDH, and cortisol. Meanwhile, serum acetylcholinesterase, ALP, and LDH were significantly reduced. In addition, antioxidant enzymes (SOD, CAT, GST, and TAC) levels were reduced in 4-NP treated fish compared to control. Also, there were significant increments in hepatic LPO, DNA fragmentation, and apoptotic erythrocytes in 4-NP treated fish compared to control. Liver of 4-NP treated fish showed some histopathological alterations such as, vacuolization in hepatocytes, congestion in central vein, infiltration of mononuclear inflammatory cells, and necrosis as well as depletion of glycogen content of liver. Addition of green tea extract into the water restored the alterations in most of those biomarkers induced by 4-NP. We concluded that, GTE has a protective role against hepatic failure, depletion of antioxidant defense, and genotoxicity induced 4-NP in C. gariepinus.

Increased water temperature altered hemato-biochemical parameters and structure of peripheral erythrocytes in striped catfish Pangasianodon hypophthalmus.

The increase of water temperature due to global warming is a great concern of aquaculturists and fishery biologists. In the present study, we examined the effects of high temperature on hematological parameters and blood glucose levels in striped catfish, Pangasianodon hypophthalmus exposed to three temperature conditions (28, 32, and 36 °C) for 7 days. Fish were sacrificed at days 1, 3, and 7. Erythroblasts (Ebs), erythrocytic cellular abnormalities (ECA), and erythrocytic nuclear abnormalities (ENA) were assayed using peripheral erythrocytes of the sampled fishes. Hemoglobin (Hb) and red blood cell (RBC) significantly (P < 0.05) decreased at 36 °C after 3 and 7 days of exposure, whereas white blood cell (WBC) showed opposite scenario. Blood glucose levels significantly (P < 0.05) increased at 36 °C on day 3. Frequencies of Ebs, ECA, and ENA were found to be elevated at increased temperature. Differential leucocytes count showed significant increases in neutrophil and decreases in lymphocytes in the highest temperature (36 °C). Dissolved oxygen decreased and free CO2 increased significantly (P < 0.05) with increasing temperature, while the pH and total alkalinity of the water were almost unchanged throughout the study period. Therefore, the present study demonstrated that striped catfish feel better adaptation at 28 and 32 °C, while high temperature 36 °C is likely stressful to this fish species.

Identification of Differentially Regulated Edwardsiella ictaluri Proteins During Catfish Serum Treatment.

Edwardsiella ictaluri is a facultative, intracellular, gram-negative bacterium that causes enteric septicemia of catfish (ESC). Edwardsiella ictaluri is known to be resistant to defense mechanisms present in catfish serum, which might aid in its use of a host's bloodstream to become septicemic. However, the precise mechanisms of the survival of E. ictaluri in host serum are not known. Analysis of the response of E. ictaluri to the host serum treatment at a proteomic level might aid in the elucidation of its adaptation mechanisms against defense mechanisms present in catfish serum. Thus, the objective of this study was to identify differentially regulated proteins of E. ictaluri upon exposure to naïve catfish serum. Two-dimensional difference gel electrophoresis (2D-DIGE) followed by in-gel trypsin digestion and MALDI-TOF/TOF analysis were used for identification of differentially expressed E. ictaluri proteins. A total of 19 differentially regulated proteins (7 up- and 12 downregulated) were identified. Among those were four putative immunogenic proteins, two chaperones and eight proteins involved in the translational process, two nucleic acid degradation and integration proteins, two intermediary metabolism proteins, and one iron-ion-binding protein. Further research focusing on the functions of these differentially expressed proteins may reveal their roles in host adaptation by E. ictaluri.

Growth, blood health, antioxidant status and immune response in juvenile yellow catfish Pelteobagrus fulvidraco exposed to α-ethinylestradiol (EE2).

Triplicate groups of juvenile yellow catfish Pelteobagrus fulvidraco were exposed to three levels of α-ethinylestradiol (EE2) (0, 0.1 and 1 ng L-1) for 56 days. Fish survival rate (>93.33%) was not different among experimental groups. Weight gain and specific growth rate of fish exposed to EE2 were higher than those of control fish. Hepatosomatic index of fish exposed to 1 ng L-1 EE2 was the highest. Serum total protein, albumin, globulin, alanine aminotransferase, aspartate transaminase, cholesterol and triglyceride increased with increasing EE2 exposure levels. Liver total anti-oxidative capacity, malondialdehyde content and lysozyme activity of fish exposed to EE2 were higher than those of control fish. Phagocytic indices of fish exposed to 1 ng L-1 EE2 was lower than that of control fish. This study indicates that although EE2 exposure can promote the growth of yellow catfish in short-term, EE2 exerts its toxic effects by inducing reactive oxygen species generation and malondialdehyde accumulation, leading to blood deterioration and interfering with immune response.