Effects of cadmium on some haematological and biochemical characteristics of <Emphasis Type="Italic">Oreochromis niloticus</Emphasis> (Linnaeus, 1758) dietary supplemented with tomato paste and vitamin E

The present study investigates the potential protective effects of tomato paste (9 mg/kg-lycopene) in comparison with vitamin E (50 mg/kg) against the impacts of cadmium (Cd) toxicity (4.64 mg/l: ¼ of 96 h LC50) on fishes Cd exposed for 15 and 30 days. Cd impacts were evaluated in terms of biological, haematological and biochemical characteristics. Cd significantly induced free radicals in serum and liver. The activities of aspartate aminotransferase and alanine aminotransferase in serum were significantly increased due to Cd. Treatment with Cd caused a significant increase in Lipid peroxidation and DNA fragmentation in liver tissue and serum glucose and total lipid. On the other hand, Cd significantly led to decline in serum total protein, blood haemoglobin, red blood cell count, haematocrit value, mean corpuscular volume, mean corpuscular haemoglobin and mean corpuscular haemoglobin concentration. Dietary supplementation with vitamin E and/or tomato paste to Cd-exposed fish declined significantly the increased lipid peroxidation and DNA fragmentation in liver tissue and the increased aspartate aminotransferase, alanine aminotransferase, glucose and total lipid in serum to the normal condition. This supplementation also significantly increased the declined serum total protein, blood haemoglobin, red blood cell count, haematocrit value, mean corpuscular volume, mean corpuscular haemoglobin and mean corpuscular haemoglobin concentration to the normal state. Cd impacts and tomato paste/or vitamin E supplementations did not reflected on the condition factor of the fish. These findings demonstrated the beneficial diet supplementation of tomato paste phytonutrients and vitamin E in counteracting the harmful effects of Cd on the characters investigated.     

Red blood cell indices of rainbow trout Oncorhynchus mykiss (Walbaum) in aquaculture

A direct non‐parametric method was used to calculate reference (physiological) haematology values for farmed 10–12‐month rainbow trout of the Kamloops strain (mean weight: 330±131 g) with respect to red blood cell counts (RBCc), haematocrit values (Hct), haemoglobin concentrations (Hb), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH) and mean corpuscular haemoglobin concentrations (MCHC). The fish in the selected reference group (n=798) were given dry pelleted diets that contained 37–47% crude protein, 7–18% crude fat and 108–300‐mg vitamin E, 1.08–5‐mg folic acid, 0.018–0.05‐mg vitamin B₁₂, 48–64.5‐mg iron, 4.5–8.4‐mg copper and 0.18–0.24‐mg selenium supplied per kg of diet. Ethoxyquin and butylhydroxytoluol were used to protect the fat component against oxidation. The fish were kept at a stocking density of 50kg per cubic metre in tanks provided with running freshwater (dissolved oxygen 8.4–11.5 mg L^?1, with O₂ saturation of 77–98%) at an ambient temperature of 0.2–16°C. Blood was sampled between September and November at a photoperiod of 9–13 h:11–15 h (light:dark). Reference ranges for the preceding haematological indices were as follows in immature females (males): RBCc, 0.77–1.42T L^?1 (T – tera, 10¹²) (0.98–1.55T L^?1); Hct, 0.304–0.502 (0.34–0.546); Hb, 54–93 g L^?1 (59–97 g L^?1); MCV, 282–469 fL (279–434 fL); MCH, 51–86 pg (47–78 pg); MCHC, 0.15–0.22 (0.15–0.2). In males, values for RBCc, Hct and Hb were significantly higher (P=0.01 and 0.0000 respectively) and those for MCV, MCH and MCHC were significantly lower (P=0.01 and 0.0002 respectively) than in immature females. Nutritional and environmental factors affecting erythropoiesis in trout and some correlations between haematological (RBCc, Hb, Hct) and biochemical indices of the blood plasma (total protein, cholesterol) are discussed.     

Haematologic and immunologic parameters of bullfrogs,Lithobates catesbeianus,fed probiotics

The effects of two probiotics (P₁–Lactobacillus acidophilus, Bifidobacterium bifidum and Enterococcus faecium and P₂–Bacillus subtilis) supplemented to commercial feed (40% crude protein) on the haematological and immunological parameters of the bullfrog Lithobates catesbeianus were studied. Two doses of each probiotic (5 and 10 g kg^?1 of food) were added to the diets and fed to frogs, totalling five treatments over 112 days. Haematological analyses consisted of total and differential leucocyte counts, erythrocyte and thrombocyte counts, haematocrit, haemoglobin levels and RBC indices (mean corpuscular volume, mean corpuscular haemoglobin – and mean corpuscular haemoglobin concentration) and the immunological parameters included phagocytic capacity and phagocytic index of peritoneal phagocytes. The results showed that the probiotics did not significantly influence any of the haematological parameters measured. However, immunological assays showed that the probiotics had an immunostimulating effect. The greatest effects were seen with probiotic P₁ fed at a dose of 10 g kg^?1 of diet and probiotic P₂ fed at 5 g kg^?1 of diet.     

Effect of dietary prebiotic inulin on histology,immuno‐haematological and biochemical parameters of Asian seabass (Lates calcarifer)

The present study was carried out to investigate the effect of supplementation of inulin on histology, immuno‐haematological and biochemical parameters of Asian seabass (Lates calcarifer) fingerlings with an initial average body weight of 7.14 ± 0.05 g. Inulin was supplemented at four different concentrations (control) 0, 5, 10, 15, and 20 g/kg in the L. calcarifer diet containing 400 g/kg protein and 90 g/kg lipid. At the end of the 60 days feeding trial, the absorptive surface area of the intestine and glycogen deposition in liver were increased in fish fed inulin supplemented diets. The immune parameters lysozyme, alternative complement pathway, superoxide dismutase and nitroblue tetrazolium assay showed significant (p < 0.05) difference between control and treatment groups. Haematological parameters showed that red blood cells, white blood cells, haemoglobin, packed cell volume, mean corpuscular volume, mean corpuscular haemoglobin and mean corpuscular haemoglobin concentration levels increased significantly (p < 0.05) in the fish fed with inulin supplemented diets. The analysis of biochemical parameters revealed that glucose, urea, cholesterol, triglyceride, aspartate aminotransferase, alkaline phosphatase, alanine aminotransferase, and lactate dehydrogenase showed significant differences (p < 0.05) between control and treatments groups. No significant difference (p > 0.05) was observed for total protein among different treatments. The results of the study revealed that 15–20 g/kg inulin supplementation has a beneficial effect in the histology, immuno‐haematological, and biochemical parameters in L. calcarifer juveniles.     

Physiological responses to starvation in the European eel (Anguilla anguilla): effects on haematological, biochemical, non-specific immune parameters and skin structures

The physiological effects of short-term starvation on some haematological, biochemical and non-specific immune response parameters together with the histological structure of the skin, were investigated in the European eel, Anguilla anguilla. Blood haemoglobin and haematocrit, serum glucose and cortisol, hemolysins, haemagglutinins, and lysozyme in the plasma, kidney and epidermal extract, were measured in fish after 31, 42 and 58 days of starvation, and compared to those of fed fish. Starvation did not affect haemoglobin and haematocrit values, while an increase in glucose and cortisol levels was found in starved eels by day 42. Haemolytic and haemagglutinating activities decreased in starved eels. On the other hand, starvation caused an increase in the lysozyme content in the epidermal extracts, while no significant variations were observed in kidney and plasma. On the whole, no major changes in metabolic, haematological and non-specific immune parameters were observed when short-term (less than 2 months) starvation was applied to the European eel, suggesting an adaptive response to starvation, rather than a typical alarm–stress response, allowing this species to withstand food deprivation.     

Growth performance of Nile tilapia,Oreochromis niloticus,fed diets containing levels of pyridoxine and haematological response under heat stress

In order to assess the effect of dietary pyridoxine supplementation on the growth performance of Nile tilapia and the haematological response under heat stress, 192 fingerlings (8.41 ± 0.22 g) were randomly distributed into eight tanks and fed practical diets supplemented with increasing levels of pyridoxine (0.0; 5.0; 10.0 and 20.0 mg of pyridoxal HCl kg^?1 diet) for 91 days. The fish were then weighed and the diet was quantified to determine the growth performance [weight gain (WG), feed intake, feed conversion ratio, protein efficiency rate, protein retention (PR) and survival percentage]. Haematological analyses (red blood cell count, haematocrit, haemoglobin, total leucocyte and differentiation, mean corpuscular volume, mean corpuscular haemoglobin concentration, albumin, globulin and albumin/globulin ratio) were carried out and then 32 fish were transferred and subjected to heat stress (32 °C) for 3 days, after which the haematological parameters were analysed. The fish fed the unsupplemented diet showed the lowest WG and PR. For the normal growth and health of the Nile tilapia, the Pyridoxine requirement in a practical diet is 10.0 mg of pyridoxine HCl kg^?1.     

Effects of additive iron on growth,tissue distribution,haematology and immunology of gilthead sea bream, <Emphasis Type="Italic">Sparus aurata</Emphasis>

The comparative effects of iron-supplemented levels on growth, tissue distribution, haematology and immunology of gilthead sea bream, Sparus aurata (2 g) were investigated, using four organic (50, 100, 200, 300 mg ORG/kg diet) and one inorganic iron source (200 INOR mg/kg diet). Fish were treated for 12 weeks with the experimental diets and maintained at a water temperature of 19–22°C. Growth (final weight and specific growth rate), tissue distribution (spleen, liver and muscle), haematological parameters (red blood cells, haematocrit, haemoglobin and mean corpuscular haemoglobin concentration) and non-specific immune indexes (respiratory burst activity and antibacterial activity of serum) were analysed. No significant differences were found in growth and iron tissue distribution among the tested groups. Red blood cell counting was statistically higher in fish given 50 ORG, 100 ORG, 200 ORG and 200 INOR feeds. However, haematocrit, haemoglobin and mean corpuscular haemoglobin concentration were not significantly affected by increasing dietary iron. Fish receiving the 100 ORG diet had the best performance with respect to the respiratory burst activity and significantly higher values for antibacterial activity of serum were obtained in fish fed with the 300 ORG diet. The present findings provided no clear evidence of the optimum iron concentration. However, there was adequate indication that iron supplementation enhanced the performance of gilthead sea bream, mainly from a haematological and immunological point of view.     

Effects of variation in dietary contents of selenium and vitamin E on growth and physiological and haematological responses of yellowtail kingfish,Seriola lalandi

The effects of dietary selenium (Se) and vitamin E and their interaction in the nutrition of yellowtail kingfish, Seriola lalandi, were investigated. Six dietary treatments were prepared in a 3 × 2 factorial arrangement (not supplemented or supplemented with Se at 1 or 2 mg kg^?1 × supplemented with vitamin E at 40 or 180 mg kg^?1). A group of fish in triplicate were fed one of the six experimental diets for 6 weeks, and their growth performance, haematological and immune responses were measured. The results revealed positively interactive effects between dietary Se and vitamin E in yellowtail kingfish. Se significantly increased weight gain of fish fed diets low in vitamin E, but not high in vitamin E. Simultaneous supplementation of both micronutrients resulted in significant increase in serum bactericidal activity. There was no significant effect of Se or vitamin E on survival, feed intake, feed conversion ratio, haematocrit, white blood cell counts and fillet proximate composition. However, Se and vitamin E contents in fillets were significantly responsive to dietary Se and vitamin E, respectively. The supplemental level of Se at 2 mg kg^?1 significantly increased red blood cell counts and haemoglobin concentrations, while lysozyme activity in skin mucus was significantly stimulated by vitamin E. The findings of Se and vitamin E supplementation in this study can be applied to improve growth and health indices of yellowtail kingfish.     

Praziquantel treatment for yellowtail kingfish (<Emphasis Type="Italic">Seriola lalandi</Emphasis>): dose and duration safety study

Regulatory approval is being sought to use praziquantel (PZQ) to treat flukes infecting yellowtail kingfish (YTK), but accurate safety data were not available. We investigated the effect of increased doses or prolonged exposure of orally administered PZQ on YTK by assessing changes in haematological and biochemical characteristics, and mortality. Fish were intubated daily for 3 days with 0, 100, 300 and 500 mg PZQ kg^?1 BW day^?1 or once daily for 9 days at 0 and 100 mg PZQ kg^?1 BW day^?1. Blood was taken 24 h after the cessation of treatment. There was no significant difference between any of the haematological or biochemical indices in YTK treated with PZQ and controls, indicating that PZQ is safe for use at 100 mg PZQ kg^?1 BW day^?1 in YTK and that exposure to high doses or prolonged duration does not have negative effects on the YTK haematological or biochemical parameters we measured.     

Effects of stocking density on haematological parameters,growth and fin erosion of great sturgeon (Huso huso) juveniles

The influence of stocking density (1, 2, 4, 6 and 8 kg m^?2) was investigated on haematological parameters, growth and fin erosion of great sturgeon (Huso huso) juveniles for a period of 8 weeks. The mean weight of fish at the start of trial was 93.13±1.04 g. After 8 weeks of rearing, the mean weight was 362.4, 319.7, 267, 242.1 and 211.1 in densities 1–8 kg m^?2 respectively. The results of this study showed that growth parameters, including condition factor, weight, weight gain, feed conversion ratio, specific growth rate and body weight increase, had a statistically significant difference among treatments (P<0.05). A significant difference (P<0.05) was observed in haematocrit, but the other haematological parameters, including red blood cells, white blood cells (WBC), haemoglobin concentration, mean corpuscular haemoglobin, mean corpuscular volume, mean corpuscular haemoglobin concentration and differential WBC count, showed no significant effect with stocking density (P>0.05). At the end of the experiment, stocking density had no significant effect on plasma cortisol and glucose concentration. The fin length (dorsal, anal, ventral, pectoral and caudal) of fish was measured to calculate the fin index. According to this index, dorsal, anal, ventral and pectoral fins showed no significant difference among treatments (P>0.05), but the erosion of the caudal fin was significantly different between fish held on 6 and 8 kg m^?2 (P<0.05). These results showed that rearing density has a major effect on the growth indices of H. huso. Unlike many other fish, great sturgeon exhibited lower stress responses to high stocking density. This indicates that they are more tolerable to rearing conditions in high stocking densities. With respect to the various effects that density causes on growth, fin erosion and physiological and haematological parameters, better understanding of these phenomena considering different levels of density could have a beneficial impact on many rearing steps of this species.     

Transcripts of genes encoding reproductive neuroendocrine hormones and androgen receptor in the brain and testis of goldfish exposed to vinclozolin,flutamide, testosterone,and their combinations

Vinclozolin (VZ) is a pesticide that acts as an anti-androgen to impair reproduction in mammals. However, VZ-induced disruption of reproduction is largely unknown in fish. In the present study, we have established a combination exposure in which adult goldfish were exposed to VZ (30 and 100 μg/L), anti-androgen flutamide (Flu, 300 μg/L), and androgen testosterone (T, 1 μg/L) to better understand effects of VZ on reproductive endocrine system. mRNA levels of kisspeptin (kiss-1 and kiss-2) and its receptor (gpr54), salmon gonadotropin-releasing hormone (gnrh3) and androgen receptor (ar) in the mid-brain, and luteinizing hormone receptor (lhr) in the testis were analyzed and compared with those of control following 10 days of exposure. kiss-1 mRNA level was increased in goldfish exposed to 100 µg/L VZ and to Flu, while kiss-2 mRNA level was increased following exposure to Flu and to combinations of 30 µg/L VZ with Flu, 100 µg/L VZ with T, and Flu with T. gpr54 mRNA level was increased in goldfish exposed to Flu and to combination of 30 µg/L VZ with Flu and 100 µg/L VZ with T. gnrh3 mRNA level was increased in goldfish exposed to 100 µg/L VZ, to Flu, and to combinations of 30 µg/L VZ with Flu, 100 µg/L VZ with T, and Flu with T. The mid-brain ar mRNA level was increased in goldfish exposed to Flu and to combinations of 30 µg/L VZ with Flu, 100 µg/L VZ with T, and Flu with T. Testicular lhr mRNA level was increased in goldfish exposed to Flu and to combination of 30 µg/L VZ with Flu. These results suggest that VZ and Flu are capable of interfering with kisspeptin and GnRH systems to alter pituitary and testicular horonal functions in adult goldfish and the brain ar mediates VZ-induced disruption of androgen production.     

Long-term effects of intraperitoneal injection of estradiol-17β on the growth and physiology of juvenile stellate sturgeon Acipenser stellatus

Juvenile stellate sturgeon Acipenser stellatus were intraperitoneally injected with estradiol-17β (E₂; 0 and 5 mg/kg fish) to investigate the possibility of sex reversal and also determine the changes in biochemical parameters. Five-month-old fish (40.9 ± 1.1 g) were injected every 3-week interval during a 190-day trial. At the termination of the experiment, final weight and other growth parameters including weight gain and specific growth rate, hepatosomatic and viscerosomatic indices were not affected by repetitive injection of E₂. Hematological features of E₂-treated fish showed significant reductions in number of red blood cells, hemoglobin concentration, hematocrit value and mean corpuscular hemoglobin (P < 0.05), but no significant changes were observed in number of white blood cells, mean corpuscular volume and mean corpuscular hemoglobin concentration (P > 0.05). Calcium, phosphorus, glucose, triacylglycerol, cholesterol, total protein and estradiol concentrations were significantly increased in fish injected with E₂ (P < 0.001). Plasma progesterone and testosterone levels were noticeably lower in fish injected with 5 mg/kg E₂ rather than the control fish (P < 0.001). Histological observations of gonads showed that all fish injected with 5 mg/kg E₂ apparently feminized, while 66.6 % of the control group was female. These results revealed that the injection of E₂ is an effective method for feminization of stellate sturgeon without having significant inhibitory effects on growth and survival.     

Effects of dietary astaxanthins on pigmentation of flesh and tissue antioxidation of rainbow trout (Oncorhynchus mykiss)

The present study was conducted to evaluate the effects of three commercial astaxanthin preparations (100 mg kg^?1 diet) with different solubilities in water, from DSM (Dutch State Mines), BASF (Badische Anilin and Soda Fabrik) and Wisdom Company on pigmentation of flesh and antioxidation of flesh, serum and liver in rainbow trout with an initial weight of 52.07 g. After 60 days of feeding, there were no significant differences in growth or flesh proximate composition of rainbow trout among groups (P > 0.05); the Salmo Fan score, redness and astaxanthin content of flesh in rainbow trout fed diets supplemented with astaxanthins were higher than those of the control group (P < 0.05). At 0, 12, 24, 48 and 72 h after thawing, the flesh malondialdehyde (MDA) content of the three astaxanthin groups was lower than that of the control group (P < 0.05). The total antioxidation capacity (T-AOC) of liver in the three astaxanthin groups was significantly higher, but serum catalase (CAT) activities were lower, than that of the control group (P < 0.05). The results indicate that addition of 100 mg kg^?1 astaxanthin from DSM, BASF or Wisdom to the diet could improve flesh redness and liver T-AOC, reduce serum CAT, SOD and flesh MDA and extend the shelf life of flesh, in spite of the different solubilities of the three sources in water.     

Haematological and biochemical profiles of carp blood following nitrite exposure at different concentrations of chloride

Haematological parameters of 2‐year‐old carp (Cyprinus carpio L.) were assessed to study the protective effect of chloride on the health of fish exposed to elevated nitrite concentrations. Four groups of carp were exposed to different concentrations of nitrite and chloride for 96 h (group E1: 67 mg L^?1 NO₂^?, 11 mg L^?1 Cl^?; group E2: 67 mg L^?1 NO₂^?, 100 mg L^?1 Cl^?; group E3: 0 mg L^?1 O₂^?, 100 mg L^?1 Cl^? and group C: 0 mg L^?1 NO₂^?, 11 mg L^?1 Cl^?). The main haematological response of carp to an acute exposure to nitrite (group E1) was a significant decrease (P<0.05) in haemoglobin concentrations (53.40±6.61 g L^?1), haematocrit (0.21±0.02 LL^?1), erythrocyte count (1.13±0.12 TL^?1), leucocyte count (7.1±4.19 GL^?1) and lymphocyte count (5.28±2.51 GL^?1), and a significant increase in methaemoglobin concentration (90.50±4.38%, P<0.01) and mean corpuscular haemoglobin concentration (0.27±0.2 LL^?1, P<0.05). At higher chloride concentrations (group E2), a lower nitrite toxicity was observed. In group E2 carp, methaemoglobin made up 38.32±13.30%. Erythrocytes in carp exposed to nitrite showed qualitative changes. Compared with the control group C, group E1 carp showed a significantly higher number (P<0.05) of elongated erythrocytes, with the nucleus located at one cell pole (0.519±0.388 TL^?1). All erythrocytes of group E1 carp had remarkably clear cytoplasms compared with the cytoplasm in the control group C. The biochemical values found were comparable with those found in controls. The main histological lesions were found in the gills of carp exposed to nitrite and consisted of hyperplasia and an elevated number of chloride cells.     

Tolerance of Atlantic salmon (Salmo salar) to dietborne endosulfan assessed by haematology,biochemistry, histology and growth

The inclusion of plant‐based ingredients in commercial fish feeds may pose a challenge because of the presence of undesirable substances, such as the pesticide endosulfan. Waterborne endosulfan is highly toxic to fish, whereas dietborne exposure has varied toxicity in different species. To investigate the systemic effects of endosulfan exposure, quadruplicate groups of Atlantic salmon (Salmo salar) were fed either 0 (control), 0.005 mg kg^?1; the European Union's maximum limit, or 10 or 20 times this level (0.05 and 0.1 mg kg^?1 respectively) for 95 days. There were no significant differences (P > 0.05) in liver somatic index, spleen somatic index, condition factor or growth among treatments. There were no indications of liver damage in fish from any of the groups in the biomarkers measured: plasma aspartate aminotransferase, plasma alanine aminotransferase and histopathology. Similarly, there were no apparent treatment‐related effects on the haematological parameters Hct, Hb, mean corpuscular volume, mean corpuscular haemoglobin concentration and mean corpuscular haemoglobin, and blood sodium, potassium, calcium and chloride levels were not significantly (P > 0.05) different among groups. Lipid digestibility, but not energy, protein, or glycogen digestibility, was significantly (P < 0.05) reduced at the highest exposure concentration. However, no significant differences were observed in lipid production value or lipid efficiency ratio. In contrast to previous studies, clinical histological abnormalities were not observed in the intestine, liver or spleen of endosulfan‐treated fish.     

Toxicological and hematological effect of <Emphasis Type="Italic">Terminalia arjuna</Emphasis> bark extract on a freshwater catfish, <Emphasis Type="Italic">Heteropneustes fossilis</Emphasis>

Increasing demand for eco-friendly botanical piscicides and pesticides as replacements for harmful synthetic chemicals has led to investigation of new sources of plant materials. Stem bark of Terminalia arjuna, which has been used as a popular folk medicine since ancient time, was examined for its piscicidal activity. This study aims to determine toxicity of ethanol extract of T. arjuna bark on fresh water stinging catfish (Heteropneustes fossilis), along with evaluation of changes in hematological parameters of the fishes exposed to a lethal concentration. The percent mortality of fishes varied significantly in response to concentrations of the extract and exposure times (between exposure time F = 36.57, p < 0.001; between concentrations F = 39.93, p < 0.001). The lethal concentrations (LC₅₀) of ethanol extract were found to be 12.7, 8.94, 5.63 and 4.71 mg/l for 24, 48, 72 and 96 h, respectively. During acute toxicity test, blood samples of treatment fishes showed significant decreases in the red blood cells count, hematocrit content, hemoglobin concentration, mean corpuscular hemoglobin concentration and plasma protein level when compared to those of the control group, while there were significant increases in the mean corpuscular volume, mean corpuscular hemoglobin, white blood cells count and plasma glucose concentration. These results suggest that T. arjuna bark extract could be considered as a potent piscicide due to its toxic effect on fish, particularly fish hematology.     

Physiological responses to feed restriction and starvation in juvenile Siberian sturgeon Acipenser baerii (Brandt, 1869): Effects on growth,body composition and blood plasma metabolites

An 8‐week study was applied to evaluate the effects of feed restriction and starvation on growth, proximate composition, haematological and biochemical factors in juvenile Siberian sturgeon Acipenser baerii with an average weight of 54 ± 0.6 g. Fish were randomly divided into nine indoor tanks (1,050 L volume) with 30 fish per tank in a flow‐through system at 18 ± 0.4°C. Three feeding strategies were considered: I) fed at satiation (F), II) restricted feeding at the rate of 1% body weight per day (R) and III) starvation (S) each with 3 replicates. Fish were fed with commercial pellets 4 times daily, but no feed was considered for S group throughout the trial. Basal level at the start, 4 and 8 weeks after initiation of the experiment, blood samples were taken from 5 fish/tank to measure the haematological and biochemical parameters. Moreover, growth performance was recorded every 2‐week interval. At the end of the experiment, the growth parameters and proximate composition were significantly different among the treatments. As expected, the highest weight (164.7 ± 2.1 g) was observed in F group compared to R (101 ± 1.7 g), or S (42.4 ± 0.8 g) groups. The highest (12.07 ± 0.14%) and lowest (5.37 ± 0.42%) fat contents were observed in F and S groups, respectively, while the protein was not affected in R group compared with F group. In addition, most haematological and biochemical indices of Siberian sturgeon were affected by starvation at week 4 and 8, while few changes were observed in restricted feeding. The highest mean corpuscular volume, mean corpuscular haemoglobin, plasma total protein, cholesterol and triglyceride was found in S group, while the lowest value of plasma glucose was observed in this group. It can be concluded that Siberian sturgeon adjusts the physiological condition in short‐term (4 weeks) feed restriction using stored metabolites to have basal metabolism and due to this, a short period of feed restriction strategy recommends to the optimum nutritional management of Siberian sturgeon to cost‐saving during unsuitable conditions.     

Alteration in haematological and biochemical parameters of Catla catla exposed to sub-lethal concentration of cypermethrin

A 60-day experiment was carried out to study the effect of sub-lethal concentration of cypermethrin (1/10th of LC₅₀) exposure on haematological and biochemical parameters of the Indian major carp, Catla catla fingerlings. Under exposure, the total erythrocyte count, total leucocyte count, haemoglobin content and haematocrit were decreased. All the studied serum parameters viz. total serum protein, albumin, globulin contents and albumin–globulin ratio were significantly decreased in cypermethrin-exposed fishes. A marked increase was recorded in alanine aminotransferase and aspartate aminotransferase activities in liver, whereas lactate dehydrogenase activity of muscle and acetylcholine esterase activity in brain were inhibited in cypermethrin-exposed fish. The membrane transport enzymes (total adenosine triphosphatase, sodium–potassium adenosine triphosphatase and magnesium adenosine triphosphatase) activities were decreased significantly in the gills of C. catla exposed to sub-lethal concentration of cypermethrin. The present study indicates that sub-lethal exposure of C. catla fingerlings to cypermethrin alters the haematological and biochemical parameters.     

Establishment and characterization of a heart-derived cell line from goldfish (<Emphasis Type="Italic">Carassius auratus</Emphasis>)

The goldfish Carassius auratus, a freshwater fish in the family Cyprinidae, was one of the earliest fish to be domesticated for ornamental purposes. A cell line was established from goldfish heart (GH) tissue to create a biological monitoring tool for viral diseases. The GH cell line was optimally maintained at 25 °C in M199 medium supplemented with 10–20% fetal bovine serum. A chromosomal analysis indicated that the cell line remained diploid, with a mean chromosomal count of 100. In viral inoculation assays, significant cytopathic effects (CPEs) were caused by epizootic hematopoietic necrosis virus (EHNV), Andrias davidianus iridovirus (ADIV), and Bohle iridovirus (BIV) infections in the fish cells and the viral titers (average value) of EHNV, ADIV, and BIV in GH cells reached 10^5.0, 10^4.5, and 10^5.0 TCID₅₀/0.1 mL, respectively, within 7 days. However, no CPE was observed in the cells infected with viral hemorrhagic septicemia virus (VHSV), infectious hematopoietic necrosis virus (IHNV), spring viremia of carp virus (SVCV), infectious pancreatic necrosis virus (IPNV), channel catfish virus (CCV), or grass carp reovirus (GCRV). These results suggest that the GH cell line is a valuable tool for studying viral pathogenesis.     

Effect of Bacillus subtilis on Aeromonas hydrophila infection resistance in juvenile freshwater prawn, Macrobrachium rosenbergii (de Man)

This experiment was carried out to investigate the potential probiotics properties of Bacillus subtilis in protecting of juvenile freshwater prawn, Macrobrachium rosenbergii against Aeromonas hydrophila infection. A B. subtilis bacterium isolated from gut of juvenile prawns was added to the prawns feed at 10⁸ cells g^?1 feed. There were significant differences (P < 0.05) between B. subtilis-treated and control groups in growth and survival enhancement of juvenile prawns after 60 days of feeding trial. Sixty days after B. subtilis feeding trial, the prawns were challenged by bath exposure to A. hydrophila (10⁷ cells mL^?1) for 28 days. Four weeks after challenge, there was significant difference in the survival of prawns between B. subtilis-treated groups (88.33 %) and control groups (20.81 %; P < 0.05). In addition, the control groups had an unhealthy external appearance, while the treated groups, appeared healthy and normal. From this, it was concluded that the selected B. subtilis may be a promising probiotics for protection of prawns from A. hydrophila infection.