Showing papers in "Fish Physiology and Biochemistry in 2013"
TL;DR: This review highlights β-glucan as an immunostimulant, its effective dosages, and route of administration and furthermore provides an outline on role of β- glucan in enhancing growth, survival, and protection against infectious pathogens pertaining to fishes and shellfishes.
Abstract: The major hindrance in the development and sustainability of aquaculture industry is the occurrence of various diseases in the farming systems. Today, preventive and management measures are central concern to overcome such outbreak of diseases. Immunostimulants are considered as an effective tool for enhancing immune status of cultured organisms. Among different immunostimulants used in aquaculture practices, β-glucan is one of the promising immunostimulant, which is a homopolysaccharide of glucose molecule linked by the glycoside bond. It forms the major constituents of cell wall of some plants, fungi, bacteria, mushroom, yeast, and seaweeds. Major attention on β-glucan was captivated with the gain in knowledge on its receptors and the mechanism of action. The receptor present inside the animal body recognizes and binds to β-glucan, which in turn renders the animal with high resistance and enhanced immune response. This review highlights β-glucan as an immunostimulant, its effective dosages, and route of administration and furthermore provides an outline on role of β-glucan in enhancing growth, survival, and protection against infectious pathogens pertaining to fishes and shellfishes. Study also summarizes the effect of β-glucan on its receptors, recognition of proteins, immune-related enzymes, immune-related gene expression and their mechanisms of action.
336 citations
TL;DR: It seems that butyrate increased the availability of several essential amino acids and nucleotide derivatives, and the energy provision for enteric cells might have been enhanced by a decrease in glucose and amino acid oxidation related to the use ofbutyrate as fuel.
Abstract: Butyrate is a short-chain fatty acid extensively used in animal nutrition since it promotes increases in body weight and other multiple beneficial effects on the intestinal tract. Although such effects have been demonstrated in several species, very few studies have assessed them in fish. On the other hand, little is known about the metabolic processes underlying these effects. In the present work, growth parameters and changes in more than 80 intestinal metabolites (nucleotides, amino acids and derivatives, glycolytic intermediates, redox coenzymes and lipid metabolism coenzymes) have been quantified in juvenile sea bream fed a butyrate-supplemented diet. Results showed a significant increase in the weight of fish receiving butyrate, while metabolomics provided some clues on the suggested effects of this feed additive. It seems that butyrate increased the availability of several essential amino acids and nucleotide derivatives. Also, the energy provision for enteric cells might have been enhanced by a decrease in glucose and amino acid oxidation related to the use of butyrate as fuel. Additionally, butyrate might have increased transmethylation activity. This work represents an advance in the knowledge of the metabolic consequences of using butyrate as an additive in fish diets.
87 citations
TL;DR: The EOs promoted slight changes in silver catfish that enabled both an adaptive response and the recovery of most of the measured parameters after 240 min regardless of concentration or EO that was used, which support the use of EOHR and EOLA as anesthetics for fish.
Abstract: The anesthetic activities of the essential oils (EOs) of Hesperozygis ringens (EOHR) and Lippia alba (EOLA) and their effects in silver catfish (Rhamdia quelen) after anesthesia and recovery were investigated. Fish (32.19 ± 1.24 g) were submitted to one of the following treatments for each EO: basal group, control, or anesthesia (150, 300, or 450 μL L−1 EO). After that the anesthesia was induced or simulated and the biometric measurements were completed, fish were transferred to anesthetic-free aquaria to allow for recovery. Fish were sampled at 0, 15, 30, 60, and 240 min after recovery. At time 0 of recovery, the ventilatory rate was lower in the groups anesthetized with either EO. In comparison with the basal group, control fish showed an increase in plasma glucose, aspartate aminotransferase (AST), and Na+ levels and a reduction in Na+/K+-ATPase activity at 0 min of recovery. Plasma levels of ammonia and Na+ were lower in the fish anesthetized with EOLA (450 μL L−1) and EOHR (all concentrations), respectively, than in the control fish. Additionally, lactate, AST, alanine aminotransferase, K+ plasma levels, and gill Na+/K+-ATPase and H+-ATPase activities were higher in the fish anesthetized with either EOHR or EOLA than in the control fish. The EOs promoted slight changes in silver catfish that enabled both an adaptive response and the recovery of most of the measured parameters after 240 min regardless of concentration or EO that was used. These findings support the use of EOHR and EOLA as anesthetics for fish.
81 citations
TL;DR: The results showed that diazinon altered the activity of antioxidant enzymes and the cellular total antioxidant capacity inducing oxidative stress and cellular damage in hepatocytes evidenced by histopathological analysis.
Abstract: The organophosphate insecticide diazinon is widely used to control pest in Iran. The purpose of the present study was to investigate the antioxidant and histopathological changes in the liver tissue of rainbow trout (Oncorhynchus mykiss) exposed to 0.1 and 0.2 mg/L of a commercial formula of diazinon for a period of 28 days. Antioxidant enzyme activities—catalase, superoxide dismutase, glutathione peroxidase and glutathione reductase—were determined after 7, 14 and 28 days of exposure. Histopathological analyses were performed at the 28th day. All antioxidant enzymes were induced after 7 days of diazinon treatment in both concentrations of diazinon. Catalase and superoxide dismutase maintained elevated activities during all the treatment period. Glutathione peroxidase activity returned to the control values at the 14th day, decreasing to values below control at the 28th day in both diazinon concentrations. Glutathione reductase maintained increased activities at the 14th day in the 0.1 mg/L diazinon, decreasing to control values at the 28th day. In the 0.2 mg/L group, the activity returned to control values at the 14th and decreased below the control at the 28th day. Total antioxidant capacity of hepatocytes significantly decreased in fishes exposed to diazinon during all experimental periods. Hypertrophy of hepatocytes, vacuolization of cell cytoplasm and hepatocyte cloudy swelling were observed in the liver tissue of fish exposed to both concentrations of diazinon. The results showed that diazinon altered the activity of antioxidant enzymes and the cellular total antioxidant capacity inducing oxidative stress and cellular damage in hepatocytes evidenced by histopathological analysis.
78 citations
TL;DR: Higher mean corpuscular haemoglobin concentration (MCHC), blood glucose and lactate dehydrogenase (LDH) levels in T5 group revealed that higher concentration of azadirachtin have notable effects on activity of vital tissues function and physiology of the host.
Abstract: Argulosis hampers aquaculture production and alters the host physiology and growth. Azadirachtin is recognized as a potential antiparasitic agent against Argulus sp. The present study aimed to investigate the effect of different concentration of azadirachtin solution on haematological and serum biochemical parameters of Argulus-infested goldfish Carassius auratus. Ninety Argulus-infested goldfish were randomly divided into six equal groups. Fish of group 1-5 were treated with azadirachtin solution through bath of 1, 5, 10, 15 and 20 mg L(-1) as T1, T2, T3, T4 and T5, respectively, and group 6 was exposed to 2% DMSO solution without azadirachtin and considered as negative control T0(-). Along with six treatment groups, a positive control T0(+) of healthy goldfish free from Argulus infestation was also maintained. Parasitic mortality was evaluated after 3 days of consecutive bath treatment. After 7 days of post-treatment, the blood and serum were drawn from each of the treatment groups and haematological and serum biochemical parameters were evaluated. Total leucocyte count (TLC), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), blood glucose, total protein (TP), globulin, serum glutamate oxaloacetate transaminase (SGOT) and serum glutamate pyruvate transaminase (SGPT) were significantly (p < 0.05) high in negative control group when compared with positive control group. It could be concluded that Argulus infestation altered marked haematological and serum biochemical parameters. However, in treated groups complete elimination of Argulus was found in T4 and T5 groups. Also significant (p < 0.05) reduction in haematological and serum biochemical parameters of all the treatment groups were recorded in comparison with negative control group. In addition, T4 and T5 groups showed significantly (p < 0.05) high superoxide dismutase (SOD), catalase, total erythrocyte count (TEC) and haemoglobin (Hb). However, higher mean corpuscular haemoglobin concentration (MCHC), blood glucose and lactate dehydrogenase (LDH) levels in T5 group revealed that higher concentration of azadirachtin have notable effects on activity of vital tissues function and physiology of the host. Argulus spp. from infested goldfish could be eliminated using bath treatment with solution of azadirachtin having concentration of 15 mg L(-1) and that also shifted haematological and serum biochemical parameters towards homeostasis.
65 citations
TL;DR: In this article, the basic biology and physiology of germline stem cells in fish remains incomplete, imposing a considerable limitation on the application of germ cell transplantation in fish and hindering the development of new avenues of research in reproductive biotechnology and aquaculture.
Abstract: Although the use of germ cell transplantation has been relatively well established in mammals, the technique has only been adapted for use in fish after entering the 2000s. During the last decade, several different approaches have been developed for germ cell transplantation in fish using recipients of various ages and life stages, such as blastula-stage embryos, newly hatched larvae and sexually mature specimens. As germ cells can develop into live organisms through maturation and fertilization processes, germ cell transplantation in fish has opened up new avenues of research in reproductive biotechnology and aquaculture. For instance, the use of xenotransplantation in fish has lead to advances in the conservation of endangered species and the production of commercially valuable fish using surrogated recipients. Further, this could also facilitate the engineering of transgenic fish. However, as is the case with mammals, knowledge regarding the basic biology and physiology of germline stem cells in fish remains incomplete, imposing a considerable limitation on the application of germ cell transplantation in fish. Furthering our understanding of germline stem cells would contribute significantly to advances regarding germ cell transplantation in fish.
64 citations
TL;DR: The overall results in this study suggested that both VE and Se inclusion could protect largemouth bass from the oxidative damage challenged by dietary oil oxidation.
Abstract: Six oxidized fish oil contained diets were formulated to investigate the effect of graded levels of vitamin E (V(E)) (α-tocopherol acetate: 160, 280, and 400 mg kg(-1)) associated with either 1.2 or 1.8 mg kg(-1) selenium (Se) on growth, body composition, and antioxidant defense mechanism of juvenile largemouth bass. Another control diet containing fresh fish oil with 160 mg kg(-1) V(E) and 1.2 mg kg(-1) Se was also prepared. Over a 12-week feeding trial, about 5 % of Micropterus salmoide fed diet OxSe1.2/V(E)160 showed inflammation and hemorrhage symptoms at the base of dorsal, pectoral, and tail fin. Fish in all treatments survived well (above 90 %). Feed intakes (88.42-89.58 g fish(-1)) of all treatments were comparable. Growth performances (weight gain and specific growth rate) and feed utilization (feed and protein efficiency ratio) were significantly impaired by dietary oil oxidation, and they did not benefit from neither V(E) nor Se supplementation. Regardless of dietary V(E) and Se supplementation, oxidized oil ingestion resulted in markedly decreased hepatosomatic index and intraperitoneal fat ratio. Oxidized oil ingestion also induced markedly lower liver and muscle lipid contents, and these effects could be alleviated by dietary Se supplementation. Dietary oil oxidation stimulated hepatic catalase activities relative to the control, and supplementation of V(E) abrogated this effect. Hepatic reduced glutathione content in the control was markedly higher than that of treatment OxSe1.2/V(E)160, without any significant differences comparing with the other oxidized oil receiving groups. Hepatic glutathione peroxidase activity and liver Se concentration reflected dietary Se profile, whereas liver V(E) level reflected dietary V(E) profile. Compared with the control, fish fed diet OxSe1.2/V(E)160 obtained markedly higher serum, liver and muscle malondialdehyde contents, which droppe significantly with increasing either V(E) or Se supplementation. In conclusion, the overall results in this study suggested that both V(E) and Se inclusion could protect largemouth bass from the oxidative damage challenged by dietary oil oxidation.
63 citations
TL;DR: It is suggested that the HP diet may be used as functional feed since it may represent a metabolic advantage during stressful events and may counteract immunosuppression in sole.
Abstract: Amino acids (AA) regulate key metabolic pathways, including some immune responses. Therefore, this study aimed to assess whether an increased availability of dietary AA can mitigate the expected increase in plasma cortisol and metabolites levels due to high stocking density and its subsequent immunosuppression. Senegalese sole (Solea senegalensis) were maintained at low stocking density (LSD; 3.5 kg m−2) or high stocking density (HSD; 12 kg m−2) for 18 days. Additionally, both treatments were fed a control or a high protein (HP) diet (LSD, LSD HP, HSD and HSD HP). The HP diet slightly increased the levels of digestible indispensable AA, together with tyrosine and cysteine. HSD was effective in inducing a chronic stress response after 18 days of treatment since fish held at HSD presented higher plasma cortisol, glucose and lactate levels. Moreover, this increase in stress indicators translated in a decrease in plasma lysozyme, alternative complement pathway (ACP) and peroxidase activities, suggesting some degree of immunosuppression. Interestingly, while plasma glucose and lactate levels in HSD HP specimens decreased to similar values than LSD fish, plasma lysozyme, ACP and peroxidase activities increased, with even higher values than LSD groups for ACP activity. It is suggested that the HP diet may be used as functional feed since it may represent a metabolic advantage during stressful events and may counteract immunosuppression in sole.
59 citations
TL;DR: Total replacement of fish oil by vegetable oils did not induced changes in fish growth and performance, but affected fatty acid profile of muscle, liver, and intestine, reflecting those tissues the characteristic fatty acids of each type of dietary oil.
Abstract: To study the substitution of fish oil by vegetable oils in fish diets, juveniles Senegalese sole (Solea senegalensis) were fed diets (56 % crude protein, 12 % crude lipid) containing either linseed (100LO) or soybean (100SO) oils in comparison with a 100 % fish oil-based diet (100FO) for 90 days. Samples of muscle, liver, and intestine were collected for biochemical analysis and for glucocorticoid receptor-related genes, including GR1 and GR2, and the associated heat shock proteins HSP70, HSP90AA, and HSP90AB. Besides, basal levels of plasma cortisol were also determined. After the feeding period, a stress test, consisting on 5 min of net chasing, was applied to a selected population of each dietary group. Total replacement of fish oil by vegetable oils did not induced changes in fish growth and performance, but affected fatty acid profile of muscle, liver, and intestine, reflecting those tissues the characteristic fatty acids of each type of dietary oil. A tendency to conserve the ARA/EPA ratio could be observed in the different tissues, despite of the level of these fatty acids in diet. Chasing stress induced an increase of muscle GR1 and a reduction in intestinal GR2 relative expressions at any of the experimental diets assayed. In liver, chasing stress induced an increase in both GR1 and GR2 gene expression in fish fed fish oil diets. Similarly, chasing stress induced an increase of muscle HSP70 and decrease of HSP90AB in liver at any of the experimental diet assayed. Besides, vegetable oils decreased the expression of HSP70 in intestine, being the relative expression of liver HSP90AA increased by the inclusion of linseed oil in the diet, at any of the experimental conditions assayed.
55 citations
TL;DR: It has been shown that European sea bass seems to be able to efficiently use n-6 PUFA for energy substrate, and this may help in minimizing the β-oxidation of the health benefiting n-3 LC-PUFA and thus increase their deposition into fish tissues.
Abstract: Monounsaturated fatty acids (MUFA)-rich and n-6 polyunsaturated fatty acid (n-6 PUFA)-rich vegetable oils are increasingly used as fish oil replacers for aquafeed formulation. The present study investigated the fatty acid metabolism in juvenile European sea bass (Dicentrarchus labrax, 38.4 g) fed diets containing fish oil (FO, as the control treatment) or two different vegetable oils (the MUFA-rich canola/rapeseed oil, CO; and the n-6 PUFA-rich cottonseed oil, CSO) tested individually or as a 50/50 blend (CO/CSO). The whole-body fatty acid balance method was used to deduce the apparent in vivo fatty acid metabolism. No effect on growth performance and feed utilization was recorded. However, it should be noted that the fish meal content of the experimental diets was relatively high, and thus the requirement for n-3 long-chain polyunsaturated fatty acid (n-3 LC-PUFA) may have likely been fulfilled even if dietary fish oil was fully replaced by vegetable oils. Overall, relatively little apparent in vivo fatty acid bioconversion was recorded, whilst the apparent in vivo β-oxidation of dietary fatty acid was largely affected by the dietary lipid source, with higher rate of β-oxidation for those fatty acids which were provided in dietary surplus. The deposition of 20:5n-3 and 22:6n-3, as % of the dietary intake, was greatest for the fish fed on the CSO diet. It has been shown that European sea bass seems to be able to efficiently use n-6 PUFA for energy substrate, and this may help in minimizing the β-oxidation of the health benefiting n-3 LC-PUFA and thus increase their deposition into fish tissues.
53 citations
TL;DR: The response of brown-marbled grouper to drastic and gradual changes in temperature and salinity is tested to understand the grouper’s basic stress response and the results can improve the culture of grouper.
Abstract: Grouper have to face varied environmental stressors as a result of drastic changes to water conditions during the storm season. We aimed to test the response of brown-marbled grouper to drastic and gradual changes in temperature and salinity to understand the grouper’s basic stress response. The results can improve the culture of grouper. Brown-marbled grouper, Epinephelus fuscoguttatus (6.2 ± 0.8 g) were examined for temperature and salinity tolerances at nine different environmental regimes (10, 20, and 33 ‰ combined with 20, 26 and 32 °C), in which the fish were subjected to both gradual and sudden changes in temperature and salinity. The critical thermal maximum (50 % CTMAX) and the upper incipient lethal temperature (UILT) were in the ranges of 35.9–38.3 and 32.7–36.5 °C, respectively. The critical thermal minimum (50 % CTMIN) and the lower incipient lethal temperature (LILT) were in the ranges of 9.8–12.2 and 14.9–22.3 °C, respectively. The critical salinity maximum (50 % CSMAX) and the upper incipient lethal salinity (UILS) were in the ranges of 67.0–75.5 and 54.2–64.8 ‰, respectively. Fish at temperature of 20 °C and a salinity of 33 ‰ tolerated temperatures as low as 10 °C when the temperature was gradually decreased. Fish acclimated at salinities of 10–33 ‰ and a temperature of 32 °C tolerated salinities of as high as 75–79 ‰. All fish survived from accumulating salinity after acute transfer to 20, 10, 5, and 3 ‰. But all fish died while transferred to 0 ‰. Relationships among the UILT, LILT, 50 % CTMAX, 50 % CTMIN, UILS, 50 % CSMAX, salinity, and temperature were examined. The grouper’s temperature and salinity tolerance elevated by increasing acclimation temperature and salinity. On the contrary, the grouper’s temperature and salinity tolerance degraded by decreasing acclimation temperature and salinity. The tolerance of temperature and salinity on grouper in gradual changes were higher than in drastic changes.
TL;DR: The increase in CTmax, LTmax and oxygen consumption rate with increasing AT may suggest that the thermal tolerance of T. putitora is dependent on its prior thermal exposure history, and it could adapt to higher AT by altering its haemato-biochemical variables.
Abstract: A 30-day acclimation trial was conducted using Tor putitora to elucidate its thermal tolerance, oxygen consumption, haemato-biochemical variables and selected enzymatic activities at five acclimation temperatures (AT). Juveniles of T. putitora were randomly distributed among five treatment groups (20, 23, 26, 29 and 32 ± 0.5 °C). There was a significant curvilinear increase in critical thermal maxima (CTmax) (y = −0.0693x
2 + 1.7927x + 34.628, R
2 = 0.996) and lethal thermal maxima (LTmax) (y = −0.1493x
2 + 2.3407x + 35.092, R
2 = 0.991) with increasing AT. The oxygen consumption rate increased significantly with increasing AT. The Q
10 values were 1.16 between 20 and 23 °C, 3.09 between 23 and 26 °C, 1.31 between 26 and 29 °C and 1.76 between 29 and 32 °C of AT. The acclimation response ratios were ranged between 0.37 and 0.59. Catalase, superoxide dismutase and ATPase activities were increased linearly in liver, gill and kidney, while brain acetylcholine esterase activity decreased linearly with increasing AT. Blood glucose remained unchanged up to AT of 26 °C and increased significantly at AT of 29 and 32 °C. Haemoglobin content was increased linearly with increasing AT. The highest WBC count was observed at 20 °C, and no significant changes found till AT of 26 °C and significantly decreased at 32 °C. Total serum protein and globulin were significantly decreased with increasing AT. Highest values were observed at 20 °C and remained consistent till 26 °C, then decreased significantly. There was no significant change in A/G ratio through the AT 20–29 °C and increased significantly at 32 °C. The increase in CTmax, LTmax and oxygen consumption rate with increasing AT may suggest that the thermal tolerance of T. putitora is dependent on its prior thermal exposure history, and it could adapt to higher AT by altering its haemato-biochemical variables.
TL;DR: Since live weight gain and protein deposition are the key parameters for estimating nutrient requirement, these tools were used to recommend the lysine requirement of fingerling C. catla which ranges between 1.7 and 1.8 % dry diet, corresponding to 5.2–5.5 % dietary protein.
Abstract: A 12-week experiment was conducted to quantify dietary lysine requirement of fingerling Catla catla (3.65 ± 0.05 cm; 0.58 ± 0.02 g) by feeding casein–gelatine-based diets (33.0 % crude protein; 14.3 kJ/g digestible energy) with six levels of l-lysine (1.25, 1.50, 1.75, 2.00, 2.25 and 2.50 % dry diet). The experiment was conducted in eighteen 70-L indoor polyvinyl circular troughs provided with a water flow-through system (1–1.5 L/min). Live weight gain (LWG), feed conversion ratio (FCR), protein deposition (PD), lysine retention efficiency (LRE%) and RNA/DNA ratio were used as the response criteria. Second-degree polynomial regression analysis at 95 % maximum and minimum response of LWG and FCR data exhibited the lysine requirement between 1.8 and 1.9 % dry diet, corresponding to 5.5–5.7 % dietary protein. Regression analysis of PD, LRE and RNA/DNA ratio yielded the requirement between 1.7 and 1.8 % dry diet, corresponding to 5.2–5.5 % dietary protein. Since live weight gain and protein deposition are the key parameters for estimating nutrient requirement, these tools were used to recommend the lysine requirement of fingerling C. catla which ranges between 1.7 and 1.8 % dry diet. Data generated during this study will be useful to formulate lysine-balanced feed for intensive culture of this fish.
TL;DR: Results revealed the importance of taking into account the time of day when assessing stress responses and evaluating physiological indicators of stress in fish, and confirmed the existence of circadian cortisol and behavioral circadian rhythms in flat fish.
Abstract: The existence of daily rhythms under light/dark (LD) cycles in plasma cortisol, blood glucose and locomotor and self-feeding activities, as well as their persistence (circadian nature) under constant light (LL), was investigated in Senegalese sole (Solea senegalensis). For the cortisol and glucose rhythms study, 48 soles were equally distributed in 8 tanks and exposed to a 12:12 LD cycle and natural water temperature (experiment 1). After an acclimation period, blood was sampled every 3 h until a 24-h cycle was completed. Blood glucose levels were measured immediately after sampling, while plasma cortisol was measured later by ELISA. In experiment 2, the fish were exposed to LL for 11 days, and after this period, the same sampling procedure was repeated. For the study of locomotor and self-feeding rhythms (experiment 3), two groups of sole were used: one exposed to LD and the other to LL. Each group was distributed within 3 tanks equipped with infrared photocells for the record of locomotor activity, and self-feeders for feeding behavior characterization. The results revealed a marked oscillation in cortisol concentrations during the daily cycle under LD, with a peak (35.65 ± 3.14 ng/ml) in the afternoon (15:00 h) and very low levels during the night (5.30 ± 1.09 ng/ml). This cortisol rhythm persisted under LL conditions, with lower values (mean cortisol concentration = 7.12 ± 1.11 ng/ml) and with the peak shifted by 3 h. Both rhythms were confirmed by COSINOR analysis (p < 0.05). The synchronizing role of temperature and feeding schedule, in addition to light, is also discussed. Diel rhythms of glucose were not evident in LD or LL. As to locomotor and self-feeding activity, a very marked rhythm was observed under LD, with higher activity observed during the night, with acrophases located at 2:14 and 3:37 h, respectively. The statistical significance of daily rhythms was confirmed by COSINOR analysis. Under LL, both feeding and locomotor rhythms persisted, with an endogenous period (τ) around 22.5 h. In short, our findings described for the first time the existence of circadian cortisol and behavioral circadian rhythms in flat fish. Such results revealed the importance of taking into account the time of day when assessing stress responses and evaluating physiological indicators of stress in fish.
TL;DR: The TLC separation and HPLC quantification of petroleum ether/acetone extract of CE showed the peaks for highly efficient flavonoids such as rutein, quercetin and luteolin, which might be due to its rich flavonoid effect.
Abstract: Acetaminophen (APAP)-induced liver damage is one of the most common problems among the population. Therefore, the study was aimed to investigate the hepatoprotective effect of celery leaves on APAP-induced toxicity in a freshwater fish, Pangasius sutchi. Fish were divided into four experimental groups of 6 fish each. Group 1 served as control. Group 2 fish were exposed to APAP (500 mg/kg) for 24 h. Groups 3 and 4 fish were exposed to APAP + celery leaf powder (CE) (500 mg/kg) and CE for 24 h, respectively. The severity of liver damage, hepatic lipid, glycogen, ions status and histological alterations was examined. The characterization of CE extract was also performed. APAP-exposed fish showed elevated levels of both circulating and tissue hepatotoxic markers (AST, ALT and ALP), reduced hepatic glycogen and lipid contents (TG and cholesterol), increased tissue lipid peroxidation markers (TBARS, LHP and PCO), altered tissue levels of enzymatic (SOD, CAT, GPx and GST) and non-enzymatic (GSH) antioxidants and cellular thiol levels (T-SH, P-SH and NP-SH), and reduced hepatic ions (Na+, K+ and Ca2+) and abnormal liver histology. The abnormalities associated with APAP exposure were reversed on treatment with CE. The TLC separation and HPLC quantification of petroleum ether/acetone extract of CE showed the peaks for highly efficient flavonoids such as rutein, quercetin and luteolin. The observed hepatoprotective effect of CE might be due to its rich flavonoids.
TL;DR: Camelina oil can reduce the amount ofFish oil needed to meet lipid requirements, although replacing 80 % of fish oil reduced LC PUFAs in both tissues.
Abstract: Camelina (Camelina sativa) oil was tested as a replacement for fish oil in diets for farmed Atlantic cod (Gadus morhua). Camelina differs from other plant oilseeds previously used in aquaculture with high lipid (40 %), α-linolenic acid (40 %), antioxidants and low proportions of saturated fats. Dietary treatments were fed to cod (19 g fish−1 initial weight) for 9 weeks and included a fish oil control (FO), 40 % (CO40) and 80 % (CO80) replacement of fish oil with camelina oil. There was no effect of replacing fish oil with camelina oil included at levels up to 80 % on the growth performance. Cod fed CO80 stored more lipid in the liver (p CO40 > CO80; p < 0.01) and increased in total ω6 fatty acids (FO < CO40 < CO80; p < 0.01). In the liver, long-chain (LC) PUFA such as 20:4ω6, 20:5ω3, 22:5ω3 and 22:6ω3 decreased when fish oil was removed from the diet (p < 0.05), and increased in 18-carbon fatty acids (p < 0.01). Camelina oil can reduce the amount of fish oil needed to meet lipid requirements, although replacing 80 % of fish oil reduced LC PUFAs in both tissues. A comparison of BF3 and H2SO4 as catalysts to transmethylate cod liver and muscle lipids revealed small but significant differences in some fatty acid proportions.
TL;DR: The morphological traits, body composition, body fat and oxidative stress of Sparus aurata under two stress conditions: a low weekly exposure to the pesticide Diuron and chronic handling stress shows that oxidative stress sensitivity to chemical stress and shows that also could be an appropriate indicator of handling stress.
Abstract: This work investigates the changes in the morphological traits, body composition, body fat and oxidative stress of Sparus aurata under two stress conditions: a low weekly exposure to the pesticide Diuron and chronic handling stress. The fish exposed to handling stress showed lower values in the morphological traits and perivisceral fat, whereas chemical stress induced a decrease in the percentage of muscle and carcase and an increase in the percentage of spleen and hepatosomatic index. The two stress situations produced changes in the FRAP (ferric reducing antioxidant power) levels in all organs studied with a particularly marked response for Diuron in the gill. No significant differences in the ROS (reactive oxygen species) level were found for the digestive tract or the gill. In muscle, only Diuron produced a significant increase in ROS, while in liver, both treatments increased the ROS levels. This supports the oxidative stress sensitivity to chemical stress and shows that also could be an appropriate indicator of handling stress. The morphological indexes and body components examined could be practical and easy welfare indicators. Nevertheless, further works must be needed to use under the production conditions in fish farms.
TL;DR: Results showed that A. tropicus have a functional stomach in which protein hydrolysis starts with pepsin and which contains endo- and exopeptidases that are resistant to high temperatures and pH values and could adapt rapidly to consume a compound diet with different animal protein sources.
Abstract: Tropical gar (Atractosteus tropicus) is an economically and socially important freshwater species from Southeastern Mexico, with a high aquaculture potential. With this in mind, the purpose of this study was to characterize the digestive proteases of tropical gar juveniles through biochemical and electrophoretic analyses. Twenty specimens with an average weight of 73.6 ± 12.7 g were used to obtain stomach and intestinal tissue from which multienzymatic extracts were prepared. The general activities of the acid and alkaline proteases were evaluated, as well as the specific activities of trypsin, chymotrypsin, leucine aminopeptidase and carboxypeptidase A. The effect of the pH and temperature on the proteases was also analyzed, together with the composition of the multienzymatic extracts using protease inhibitors and electrophoretic tests. Results showed that A. tropicus have a functional stomach in which protein hydrolysis starts with pepsin and which contains endo- and exopeptidases (trypsin, chymotrypsin, leucine aminopeptidase and carboxypeptidase A) and proteases that are resistant to high temperatures (45 and 55 °C for alkaline and acid proteases, respectively) and pH values. Using zymogram technique, we found two acid protease isoforms (0.35 and 0.71 rf) and five alkaline protease isoforms (83.7, 43.7, 27.5, 24.0 and 19.4 kDa), which decrease or disappear with the different inhibitors. Thus, this species is considered to be a carnivore capable of adapting to its environment by consuming different types of proteins from preys and also could adapt rapidly to consume a compound diet with different animal protein sources.
TL;DR: The histopathological studies revealed seasonal and spatial differences in the lesion grade of alterations observing the highest lesion grades in fish from Odiel River and autumn season, and calculated IPAT demonstrated a low–moderate impact of pollutants on health fish.
Abstract: As a component of a large research project to evaluate the effects of contaminants on fish health in the field, histopathological studies have been conducted to help establish causal relationship between pollutants (heavy metals and aromatic polycyclic hydrocarbons—PAHs) and histopathological responses in Senegal sole, Solea senegalensis, from an estuary of SW Spain. Heavy metals (As, Zn, Cd, Pb, Cu and Fe) and 16 PAHs (proprietary USEPA) concentrations in water, sediment and tissues (liver and gills) and histopathological alterations in S. senegalensis from three sampling sites of Ria de Huelva estuary during 2004–2006 years have been analysed. The histopathological studies revealed seasonal and spatial differences in the lesion grade of alterations observing the highest lesion grades in fish from Odiel River and autumn season. No significant differences were observed in the alterations prevalence between sampling sites, but significant differences were observed between seasons observing the highest prevalence in autumn season. However, calculated IPAT demonstrated a low–moderate impact of pollutants on health fish. Correlations between histopathological alterations and pollutants analysed were observed being heavy metals the group that presented a major number of correlations with alterations in several organs of S. senegalensis. In evaluating the general health of fish, the use of histopathological studies in recommended for making more reliable assessment of biochemical responses in fish exposed to a variety of environmental stressors. Statistical analysis using semiquantitative data on pathological lesions can help to establish correlation between cause (stressor) and effect (biomarker).
TL;DR: In maturing male salmon, higher hepatic leptin (lepa1) gene expression levels were observed during mid-spermatogenesis compared to immature fish, and an upregulation of leptin during sexual maturation has been observed in a few other teleost species.
Abstract: Leptin plays an important role in energy homeostasis and reproductive function in mammals, while its function in fish is still poorly understood, especially its role in reproduction In the present study, leptin gene expression and circulating leptin plasma levels were measured during sexual maturation in male Atlantic salmon parr In maturing male salmon, higher hepatic leptin (lepa1) gene expression levels were observed during mid-spermatogenesis compared to immature fish An upregulation of leptin during sexual maturation has also been observed in a few other teleost species The physiological significance of elevated leptin levels during the maturational process in teleosts remains to be explored
TL;DR: The results show that a metal-naïve juvenile fish can endure deleterious effects when exposed to low, ecologically relevant, concentrations of a common toxic metal and that the pattern of Cd-induced histopathological alterations can be complex and linked to organ-specific responses and metal translocation within the organism.
Abstract: A histopathological screening was performed on juvenile Senegalese soles exposed to environmentally realistic concentrations of waterborne Cd (0.5, 5 and 10 μg L−1) for 28 days. The severity and dissemination of histopathological changes were variable and limited to the kidney, liver, spleen, gills and skin goblet cells. Contradicting available literature that refers the liver as the most affected organ upon acute exposure and the kidney following chronic exposure, the liver was the most impacted organ (even at the lowest concentration), in a trend that could relate to the duration of exposure and Cd concentration. The most noticeable hepatic alterations related to inflammation, although hepatocellular alterations like lipidosis and eosinophilic foci also occurred. The trunk kidney of exposed fish endured moderate inflammation, apoptosis and necrosis, however, without a clear time-dependent effect. The spleen of fish subjected to the highest concentrations revealed diffuse necrotic foci accompanied by melanomacrophage intrusion. The gills, albeit the most important apical uptake organ of dissolved toxicants, sustained only moderate damage, from epithelial hyperplasia and pavement cell detachment to the potentially more severe chloride cell alterations. In the skin, an increase in goblet cell size occurred, most notoriously correlated to Cd concentration at earlier stages of exposure. The results show that a metal-naive juvenile fish can endure deleterious effects when exposed to low, ecologically relevant, concentrations of a common toxic metal and that the pattern of Cd-induced histopathological alterations can be complex and linked to organ-specific responses and metal translocation within the organism.
TL;DR: Results suggested that elevating StAR transcription might not be necessary for a short-term response to acute stress, and a possible role for PPARα in the expression of PEPCK following acute stress is proposed.
Abstract: Dietary fatty acids, particularly arachidonic acid (ARA), affect cortisol and may influence the expression of genes involved in stress response in fish. The involvement of ARA on stress, lipid, and eicosanoid metabolism genes, in Senegalese sole, was tested. Post-larvae were fed Artemia presenting graded ARA levels (0.1, 0.4, 0.8, 1.7, and 2.3%, dry matter basis), from 22 to 35 days after hatch. Whole-body cortisol levels were determined, before and 3 h after a 2 min air exposure, as well as the expression of phospholipase A2 (PLA 2 ), cyclooxygenase-2 (COX-2), steroidogenic acute regulatory protein (StAR), glucocorticoid receptors (GRs), phosphoenolpyruvate carboxykinase (PEPCK), and peroxisome proliferator-activated receptor alpha (PPARα). Relative growth rate (6.0-7.8% day(-1)) and survival at the end of the experiment (91-96%) and after stress (100%) were unaffected. Fish reflected dietary ARA content and post-stress cortisol increased with ARA supply up to 1.7%, whereas 2.3% ARA seemed to enhance basal cortisol slightly and alter the response to stress. Results suggested that elevating StAR transcription might not be necessary for a short-term response to acute stress. Basal cortisol and PLA 2 expression were strongly correlated, indicating a potential role for this enzyme in steroidogenesis. Under basal conditions, larval ARA was associated with GR1 expression, whereas the glucocorticoid responsive gene PEPCK was strongly related with cortisol but not GR1 mRNA levels, suggesting the latter might not reflect the amount of GR1 protein in sole. Furthermore, a possible role for PPARα in the expression of PEPCK following acute stress is proposed.
TL;DR: The sex differentiation period of the Siberian sturgeon was investigated through expression profiling of two testicular markers (dmrt1 and sox9), which suggest that fish undergoing male differentiation can be identified by their profiles of gene expression before they undergo morphological differentiation.
Abstract: The sex differentiation period of the Siberian sturgeon was investigated through expression profiling of two testicular markers (dmrt1 and sox9). At the molecular level, a clear sexual dimorphism of dmrt1 and sox9 was observed in 3-year-old fish with immature gonads, in which males showed higher expression of these genes. Among 16-month-old sturgeons cultured in Uruguay, gonad morphology analyses showed one group of fish with undifferentiated gonads and a second group which had started their histological differentiation into ovaries or testes. dmrt1 showed a significantly higher expression in testes of recently differentiated fish, but this was not the case for sox9. In undifferentiated fish, we observed two clearly different groups in terms of expression: one group of fish over-expressing male markers (dmrt1, sox9) and another group of fish showing very low expression of these genes. This suggests that fish undergoing male differentiation can be identified by their profiles of gene expression before they undergo morphological differentiation.
TL;DR: An increase in hypoxia tolerance allows Atlantic stingrays to forage for longer times and across a wide range of hypoxic habitats that are less accessible to predators and competitors.
Abstract: Atlantic stingrays, Dasyatis sabina, are common residents of shallow-water seagrass habitats that experience natural cycles of severe hypoxia during summer months We hypothesized that stingrays exposed to hypoxic episodes would improve their hypoxia tolerance by increasing branchial surface area and altering blood oxygen-carrying capacity To this end, we compared critical oxygen minimum, gill morphology, and hemoglobin/hematocrit levels in a control group of Atlantic stingrays held at continuous oxygen saturations of 80-90% (≥55 mg/l), to treatment groups exposed to a 7-h hypoxic interval at 55% (~40 mg/l), or 30% oxygen saturation (~20 mg/l) Stingrays in hypoxic treatment groups significantly improved their hypoxia tolerance Critical oxygen minimum values fell from 07 ± 011 mg/l in control fish to 04 ± 005 and 04 ± 006 mg/l in the 55 and 30% saturation treatment groups, respectively Mass-specific gill surface area between control fish and the 30% saturation treatment group increased by 17-fold, from 85 to 142 mm(2)/g Although stingrays did not show an increase in hematocrit or hemoglobin levels, production of more efficient hemoglobin isoforms could not be ruled out An increase in hypoxia tolerance allows Atlantic stingrays to forage for longer times and across a wide range of hypoxic habitats that are less accessible to predators and competitors
TL;DR: All metal exposures reduced hematopoietic potential of fish measured as the ratio of proliferating to apoptotic precursor cell frequency, however, in all cases, he matopoetic activity was higher than 1 showing that the rate of repair of hematoplastic tissue prevailed over destruction.
Abstract: The effects of cadmium and copper on activity of common carp head kidney hematopoietic tissue were evaluated. The fish were subjected to short-term (3 h, Cd-s and Cu-s) or long-term (4 weeks, Cd-l and Cu-l) exposures to 100 % 96hLC50 or 10 % 96hLC50, respectively. Head kidneys were isolated weekly from 5 fish of each group for 4 weeks (post-short-term exposure and during long-term exposure). Percentage of early blast cells among the hematopoietic precursors was calculated. Proliferative and apoptotic activity were evaluated using immunocytochemical staining for proliferating cell nuclear antigen (PCNA) and caspase 3, respectively. Hematopoietic activity was calculated as the ratio of proliferating to apoptotic cells. All metal exposures induced an increase in frequency of early blast cells. The frequency of proliferating (PCNA-positive) cells also significantly increased. A considerable and significant increase in the frequency of apoptotic cells was the most pronounced effect of metal exposures. Both short-term and long-term treatments caused similar effects, but in case of Cd exposures, the reaction was more pronounced. All metal exposures reduced hematopoietic potential of fish measured as the ratio of proliferating to apoptotic precursor cell frequency. However, in all cases, hematopoietic activity was higher than 1 showing that the rate of repair of hematopoietic tissue prevailed over destruction.
TL;DR: The present results suggested that histidine could improve antioxidant capacity and inhibit lipid peroxidation and protein oxidation of juvenile Jian carp.
Abstract: In the present study, we tested the hypothesis that dietary histidine could improve antioxidant capacity of juvenile Jian carp (Cyprinus carpio var. Jian). A total of 1,200 juvenile Jian carp were fed graded levels of histidine at 2.3 (unsupplemented control), 4.4, 6.3, 8.6, 10.8 and 12.7 g/kg diet for 60 days. Results showed that the content of malondialdehyde (MDA) and protein carbonyl (PC) in serum and all tissues apparently decreased with increasing histidine levels up to an optimal level and increased thereafter. Anti-superoxide anion (ASA) capacity, glutathione peroxidase (GPX) activities and glutathione (GSH) content in serum and all tissues, anti-hydroxyl radical (a-HR) capacity, catalase (CAT) and glutathione-S-transferase (GST) activities in serum, muscle and intestine, superoxide dismutase (SOD) activities in serum and intestine, as well as glutathione reductase (GR) activity in serum, muscle and hepatopancreas were improved by dietary histidine. Fish fed diet with 8.6 g/kg histidine had lower serum glutamate-pyruvate transaminase (GPT) activity than that fed with control diet, whereas pattern of glutamate–oxaloacetate transaminase (GOT) activity was opposite. The present results suggested that histidine could improve antioxidant capacity and inhibit lipid peroxidation and protein oxidation of juvenile Jian carp.
TL;DR: The data suggest that this freshwater fish can be adversely affected by cyanobacterial blooms, however, the rapid decrease of the detectable MCLR in both tissues could imply that sublethal toxin accumulation is rapidly reversed.
Abstract: We studied accumulation and biochemical effects of microcystin-LR (MCLR) in Odontesthes hatcheri after dietary administration of the cyanobacteria Microcystis aeruginosa (1.3 μg MCLR/g body mass, incorporated in standard fish food). After 12 h, MCLR content in liver did not differ between fish fed with crushed or intact cells, demonstrating O. hatcheri’s capacity to digest cyanobacteria and absorb MCLR. In the second experiment, fish received toxic cells, non-toxic cells, or control food; MCLR accumulation was monitored for 48 h. Protein phosphatase 1 (PP1), catalase (CAT), glutathione-S-transferase (GST) activities, and lipid peroxidation (as MDA) were measured in liver and intestine. Methanol-extractable MCLR was determined by PP1 inhibition assay (PPIA); extractable and protein-bound MCLR were measured by Lemieux oxidation-gas chromatography/mass spectrometry (GC/MS). MCLR accumulated rapidly up to 22.9 and 9.4 μg MCLR/g in intestine and liver, respectively, followed by a decreasing tendency. Protein-bound MCLR represented 66 to ca. 100 % of total MCLR in both tissues. PP1 activity remained unchanged in intestine but was increased in liver of MCLR treated fish.CAT and GST activities and MDA content were significantly increased by MCLR only in liver. We conclude that O. hatcheri is able to digest cyanobacteria, accumulating MCLR mostly bound to proteins. Our data suggest that this freshwater fish can be adversely affected by cyanobacterial blooms. However, the rapid decrease of the detectable MCLR in both tissues could imply that sublethal toxin accumulation is rapidly reversed.
TL;DR: Overall results indicated that dietary microbial levan at 0.75 % in C. carpio fry ameliorated the negative effects of fipronil and augmented the growth.
Abstract: A 60-day feeding trial was conducted to study the effect of dietary microbial levan on growth performance and metabolic responses of Cyprinus carpio fry exposed to sublethal dose (1/10th LC50) of fipronil [(±)-5-amino-1-(2,6-dichloro-α,α,α-trifluoro-p-tolyl)-4-trifluoromethylsulfinylpyrazole-3-carbonitrile]. Two hundred and twenty five fry were randomly distributed in five treatments in triplicates. Four purified diets were prepared with graded levels of microbial levan. Five different treatment groups were levan control L0P0 (basal feed + 0 % levan without exposure to pesticide); pesticide control L0P1 (basal feed + 0 % levan with exposure to pesticide); L0.25P1 (basal feed + 0.25 % levan with exposure to pesticide); L0.50P1 (basal feed + 0.50 % levan with exposure to pesticide); and L0.75P1 (basal feed + 0.75 % levan with exposure to pesticide). Weight gain% and specific growth rate were significantly higher (p < 0.05) in levan fed groups compared to their non-levan fed counterpart. Highest (p < 0.05) content of ascorbic acid in muscle, liver and brain tissues was observed with higher level of dietary levan. Glucose-6-phosphate dehydrogenase activity decreased with the increasing level of dietary levan in the liver and muscle. Aspartate aminotransferase activity exhibited a second order polynomial relationship with the dietary levan, both in liver (Y = −1.001x 2 + 5.366x + 5.812, r 2 = 0.887) and muscle (Y = −0.566x 2 + 2.833x + 6.506, r 2 = 0.858) while alanine aminotransferase activity showed third order polynomial relationship both in liver (Y = 1.195x 3 − 12.30x 2 + 35.23x + 9.874, r 2 = 0.879) and muscle (Y = 0.527x 3 − 8.429x 2 + 31.80x + 8.718, r 2 = 0.990). Highest (p < 0.05) superoxide dismutase activity in gill was observed in the group fed with 0.75 % levan supplemented diet. Overall results indicated that dietary microbial levan at 0.75 % in C. carpio fry ameliorated the negative effects of fipronil and augmented the growth.
TL;DR: The ontogenesis of main pancreatic and intestinal enzymes was investigated in the recent promising Mediterranean candidate species of meagre during larval development until 40 days after hatching (DAH), indicating maturation of the intestinal digestive process and the transition of an adult mode of digestion.
Abstract: The ontogenesis of main pancreatic and intestinal enzymes was investigated in the recent promising Mediterranean candidate species of meagre, Argyrosomus regius, during larval development until 40 days after hatching (DAH). The green-water technique was carried out for larval rearing. Whole-body homogenates were used for enzymatic analysis in larvae younger than 15 DAH; after this date, older larvae were dissected into two segments as pancreatic and intestinal segment. Trypsin was detected as early as hatching and sharply increased concurrently with age and exogenous feeding 15 DAH, but constant decline was observed until the end of experiment. Amylase was determined at 2 DAH and sharply increased 10 DAH. Then, slight decreases were found between 10 and 15 DAH, and then slow alterations were continued until the end of the experiment. Lipase was firstly measured on day 3; then, sudden decline was observed between 20 and 25 DAH. After this date, slow fluctuations were maintained until the end of the experiment. Pepsin was firstly assayed 15 DAH related to gastric gland secretion and sharply increased 30 DAH. Then, it slowly varied until end of the experiment. Enzymes of brush border membranes, alkaline phosphatase and aminopeptidase N showed similar pattern on specific activities during the first 10 days. Thereafter, while specific activity of alkaline phosphatase slightly decreased 15 and fluctuated until 20 DAH, aminopeptidase N activity slowly increased 20 DAH. Then, activity of alkaline phosphatase and aminopeptidase N constantly increased 30 DAH, indicating maturation of the intestinal digestive process, and also, these activities continued to slowly increase until the end of the experiment. The specific activity of cytosolic peptidase, leucine–alanine peptidase, smoothly increased on day 8, then fluctuated until 15 DAH. After this date, in contrast to enzymes of brush border membranes, it sharply decreased 25 DAH and continued to gradually decline until the end of the experiment. These converse expressions were indicative of a maturation of enterocytes and the transition of an adult mode of digestion.
TL;DR: Gonad histology revealed that spermatozoa were always present in the testes which implied continuous spermatogenesis and asynchronous ovarian development pattern was observed in the ovaries and indicate that H. nemurus is a non-seasonal breeder with several spawning cycles and can be referred to as indeterminate batch spawner.
Abstract: Plasma sex steroid hormonal profile and gonad histology were correlated to study the annual reproductive cycle of Hemibagrus nemurus. Hormones were measured by Enzyme Linked Immunosorbent Assay. Gonad tissues were observed by using light microscopy. The highest testosterone (T) value for male was observed in November and that of female was in October. 11-ketotestosterone (11-KT) and 17β-estradiol (E2) levels were highest in June and November, respectively. Hormonal profiles of T, 11-KT and E2 showed several peaks which indicated a non-seasonal pattern. There were significant differences (p < 0.05) in the monthly levels of T, 11-KT and E2. Gonadosomatic index of H. nemurus ranged from 1.14 ± 0.02 % to 7.06 ± 1.40 %, and high gonadosomatic indices were recorded in May, August and November. Gonad histology revealed that spermatozoa were always present in the testes which implied continuous spermatogenesis and asynchronous ovarian development pattern was observed in the ovaries. The annual reproductive cycle of H. nemurus did not show a seasonal pattern and this indicate that H. nemurus is a non-seasonal breeder with several spawning cycles and can be referred to as indeterminate batch spawner. The major significances of this study are annual sex steroid hormonal profile and asynchronous ovarian development of H. nemurus. This information will contribute to our knowledge of reproductive biology of H. nemurus.