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1.
This study evaluated the effects of three levels of loading density (200, 300 and 400 g L−1) and four levels of duration (1, 3, 6 and 9 h) on the mortality, plasma cortisol and chloride levels and growth of rohu Labeo rohita fingerlings in a transport simulation. While total immediate mortality was low (4–12%), delayed mortality was high (27–49%). Initial capture and handling were found to constitute the most stressful phase as indicated by elevated plasma cortisol. The levels of cortisol continued to rise at 6 and 9 h after transport, with the highest level observed at 9 h after transport. The level of plasma chloride fell after transport across all density levels and treatment durations. Specific growth rate (SGR, %/day) and total bacterial density (cfu/g) were not different between and within treatments, and between treatments and the controls. This study demonstrates that transport has a profound effect on the stress responses of rohu fingerlings. Although the level of immediate mortality was low, the higher level of delayed mortality has serious implications in terms of production inefficiency for grow-out farmers.  相似文献   

2.
Hormone‐induced spawning of channel catfish held communally in tanks is a reliable method to produce channel catfish, Ictalurus punctatus ♀ × blue catfish, Ictalurus furcatus ♂, F1 hybrid catfish fry. However, mature catfish are crowded, and repeatedly handled during the process of induced ovulation. Repeated handling of gravid females is stressful and may impair ovulation, egg quality, and reproductive performance. Three trials were conducted to evaluate the effects of two methods of confining post‐hormone‐injected female channel catfish on stress response (cortisol concentrations) and reproductive performance: fish were either held individually while suspended in soft, nylon‐mesh bags or communally in a concrete tank. Percent of females ovulated to hormone treatment, relative fecundity, percent egg viability, and latency of channel catfish did not differ for fish in the two treatments. However, percent hatch and fry/kg of females was higher (P < 0.05) for fish held in bags that for fish held communally in tanks. Mean plasma cortisol response immediately prior to the first hormone injection (0 h) did not differ among fish groups in the two treatments. However, mean plasma cortisol concentrations were significantly lower (P < 0.05) for fish in the bag treatment at 16 and 36 h compared to fish held communally in tanks. Plasma estradiol levels (measure of oocyte maturation) were assessed at 0, 16, and 36 h after hormone injection; concentrations were (P < 0.05) higher at 16 h compared to 0 and 36 h; however, estradiol concentrations did not differ for fish held in the two treatments (P > 0.05). Suspending hormone‐injected broodfish individually in soft bags reduced stress response, improved egg hatching rate, and increased hybrid fry produced per kg weight of female broodfish. Using this simple technology, farmers can improve the efficiency of hatcheries producing hybrid catfish fry.  相似文献   

3.
The Atlantic salmon (Salmo salar) stress response was examined by measuring plasma cortisol, glucose and chloride in fish after water level reduction within rearing tanks. Maximum plasma cortisol levels (366±43 (SD) nM and 534±280 nM for Groups 1 and 2, respectively) were observed 20 min after application of the stressor. Cortisol levels were down to control levels 24 h later. The pattern for cortisol changes observed within these two groups were comparable. Plasma glucose and chloride concentrations did not change significantly in either of the experimental groups. The fish in group 2 were then repeatedly subjected to the same stressor every third day. After the fifth exposure to the stressor, blood was obtained from fish at times corresponding to sampling after the first exposure. Their maximum plasma cortisol level only reached 223 (±96) nM, and was down to prestress levels within 2 h. Plasma glucose and chloride concentrations did not change significantly in this second experiment. This challenge test revealed an acute primary response in Atlantic salmon without any apparent harmful secondary responses, that may thus serve as a standardized reference stressor using other fish groups under comparable conditions.  相似文献   

4.
This study investigated the potential of linalool as an anaesthetic during transportation of common carp, Cyprinus carpio. The fish were transported at a loading density of ~103 g/L for 3 hr in 12 plastic bags (3 L water and 6 L pure oxygen) divided into four triplicated treatments: control (without linalool), L50 (50 mg linalool/L), L100 (100 mg linalool/L) and L200 (200 mg linalool/L). After 3‐hr transportation, serum physiological responses and water physico‐chemical parameters were compared among the treatments. Results showed that water total and un‐ionized ammonia increased and dissolved oxygen decreased in all treatments after transportation. Water total ammonia and dissolved oxygen levels in the linalool‐treated bags were significantly lower than the control. After transportation, the control fish showed significant elevation in serum cortisol and glucose levels; however, the levels were significantly lower than the linalool‐treated fish. All fish showed similar serum lactate levels, significantly lower than the value obtained before transportation. The control fish showed serum urea levels similar to the level obtained before transportation; however, the linalool‐treated fish had significantly higher serum urea levels compared to the control and before transportation levels. After transportation, all fish had decreased serum chloride and sodium levels compared to the before transport level. Overall, the present results showed that linalool is not beneficial for carp transportation in plastic bags, because it reacts with water oxygen, increases stress in fish, interferes with ammonia excretion and has no benefits in preventing ion loss.  相似文献   

5.
The dynamics of plasma cortisol, blood glucose, plasma chloride and liver glycogen were investigated in matrinxã (Brycon cephalus) submitted to capture and various periods of crowding. A total of 400 fish (700±22 g weight) were distributed in four ponds divided into four 50‐m2 squares (25 fish/square, 350 g L?1), where they were acclimated for 30 days. On the sampling day, after 24 h without food, all fish from three squares were transferred to the fourth square. Six fish were sampled before the procedure (control group, zero time) and 1, 3, 6 and 24 h after the capture and crowding. Each sampling was performed in a different pond to prevent additional stress. Fish were anaesthetized and blood and liver collected for biochemical analysis. Water temperature, pH, dissolved oxygen, alkalinity, ammonia and nitrite levels were within acceptable levels for matrinxã rearing. Slight but not significant increases were verified in plasma cortisol and blood glucose levels, as were decreases in plasma chloride and liver glycogen levels. The results suggest that matrinxã is highly tolerant to the procedures of capture and short‐term crowding.  相似文献   

6.
Measurement of cortisol response is an important tool to asses stress in fisheries research. Radioimmunoassay (RIA) is a common method for the measure of cortisol in fish. Use of enzyme-linked immunosorbent assays (ELISA) to detect cortisol would eliminate health hazards, costs of handling radioisotopes, and the short stability time associated with RIA. Enzyme-linked immunosorbent assays have been used for the determination of cortisol in several fish species. However, the ELISA method of cortisol determination in fish lacks proper validation testing. We conducted validation procedures for multiple commercial cortisol ELISA kits and compared the results to RIA. The assays were tested for four species: (1) channel catfish Ictalurus punctatus, (2) largemouth bass Micropterus salmoides, (3) red pacu Piaractus brachypomus, and (4) golden shiners Notemigonus crysoleucas. We evaluated the ELISA methods against RIA, and determined that at least one kit is suitable (accuracy: mean recovery of spiked samples, 102.8%; reproducibility: interassay coefficient of variation < 10.5% for all species; precision: intra-assay coefficient of variation < 16.8% for all species; linearity: R 2 > 0.96 for all species) for the measurement of cortisol response in fish and comparative determination of stress. All of the ELISA assay results varied by more than 10% from the cortisol concentrations detected by the RIA. The high variability of the kit results indicates that commercial ELISA kits could be utilized for qualitative determination of cortisol in fish, but should be fully validated in each laboratory for each species before being used for research.  相似文献   

7.
The present study aimed to investigate the effects of anaesthesia with citronellal and linalool on stress, antioxidant and hydromineral responses of common carp. Eugenol was used as control anaesthetic, as it is a common anaesthetic in aquaculture. The fish (110 ± 5.65 g) were exposed to 406 mg/L citronellal, 982 mg/L linalool or 43 mg/L eugenol within 5 min (short‐term anaesthesia) or 10 and 20 mg/L of each anaesthetic for 3 hr (long‐term exposure), before blood sampling. The results showed that the short‐term anaesthesia had no significant effects on plasma lactate, sodium, chloride and phosphorus levels and blood catalase (CAT) and superoxide dismutase activities. The short‐term anaesthesia with linalool led to higher stress responses (increased cortisol and glucose levels) and oxidative stress (increased malondialdehyde [MDA] level and decreased total antioxidant capacity [TAC] and glutathione peroxidase [GPx] activity) compared to the eugenol and citronellal. Citronellal group had significantly higher cortisol and lower TAC level and GPx activity compared to eugenol group. Under the long‐term exposure, increase in anaesthetic concentration led to significant increase in plasma cortisol, glucose and phosphorus levels. The linalool‐treated fish had significantly higher cortisol and MDA levels compared to the other groups. The eugenol group had significantly higher lactate and phosphorus and lower TAC levels compared to the other groups. Although citronellal causes slight increase in plasma cortisol level, it induces lower tissue damages compared to eugenol. Thus, citronellal might be an alternative anaesthetic for carp anaesthesia based on the present tested parameters.  相似文献   

8.
The present study evaluated the physiological responses of matrinxã, Brycon cephalus (Günther) submitted to transport stress under the influence of sodium chloride. Different salt concentrations (0.0%, 0.1%, 0.3% and 0.6%) were added to four 200-L plastic tanks. Each tank was stocked with 30 fish (mean weight 1.0 ± 0.2 kg) and transported for 4 h. Blood was sampled prior to transport and immediately after and 24 and 96 h after transport. Plasma cortisol and glucose and serum sodium and potassium, plasma chloride and ammonia were analysed. Changes in plasma cortisol were observed immediately after transportation, except in fish transported in 0.3% and 0.6% salt. Twenty-four hours later, this hormone had returned to its initial level in all fish. Blood glucose was not changed in fish treated with 0.6% salt immediately after transport, and returned to the initial level within 96 h after the other treatments. All treatments resulted in lower levels of plasma chloride after transport, except for fish treated with 0.6% salt, with fish treated with 0.0% and 0.3% salt recovering 24 h later. Serum sodium decreased immediately after transport only in the control fish, returning to the initial level 24 h later. The results indicate that treatment with 0.6% NaCl reduces most of the physiological responses of matrinxã to the stress of transport.  相似文献   

9.
In addition to direct predation, cormorants can affect carp pond fish stock through disturbance and wounding of the fish. Fish stress response was evaluated by catch per unit effort (CPUE) using lift‐net sampling. A significantly higher (P<0.001) CPUE was recorded in the littoral region of ponds affected by cormorant visits (43.6 ± 39.6) in comparison with a control pond (CP) without their occurrence (0.9 ± 1.1). Stress indices, spleen somatic index (SSI) and Fulton's condition coefficient (FCC) were evaluated for fish subject to two stress factors, hunting cormorants (HC) and pond harvesting (PH), and compared with levels in fish from the CP. Both SSI and FCC decreased significantly (P<0.05) in PH and HC fish in comparison with the control group, while non‐significant differences were observed in both SSI and FCC indices among the HC and PH groups. Plasma biochemical indices (cortisol, glucose and lactate concentrations) were significantly higher (P<0.01) in the PH group as compared with the HC and CP groups. Concentrations in the HC and CP groups did not differ significantly. Total plasma protein levels were significantly higher (P<0.01) in HC fish compared with CP fish, but did not differ significantly from PH fish.  相似文献   

10.
Fish held at high stocking densities are generally exposed to chronic stress situations that impose severe energy demands and may predispose the fish to infection. Senegalese sole Solea senegalensis (Kaup) juveniles (78.8±18.9 g body weight) were maintained at low (LSD; 4 kg m?2 at the end of the experiment), medium (MSD; 9 kg m?2) and high (HSD; 14 kg m?2) stocking densities during a period of 63 days. Although disease outbreaks were observed in fish reared at HSD, growth and food consumption did not vary among different treatments. Results from plasma cortisol and free amino acids (FAAs) showed significant differences among different rearing densities pointing to HSD as stressful rearing condition. However, higher plasma glucose and osmolality levels indicated that fish held at MSD may also be under stress. The higher usage of FAAs from the HSD group may be due to the higher demand for energy production in order to cope with stressful rearing conditions, higher rate of protein synthesis or due to synthesis of other important metabolites related to stress response. Therefore, results from the present study point out to HSD as a stressful rearing condition and suggest that crowding stress may affect amino acid requirements.  相似文献   

11.
Catfish Ictalurus spp. are subjected to stressful conditions during harvest, which may be linked to fillet coloration and quality. Poor water quality in ponds, socks or hauling tanks, as well as handling stress, have been suggested to cause red fillets in catfish; however, chronic exposure has not resulted in red fillets. Short‐term occurrences of extreme poor water quality, particularly low dissolved oxygen, high carbon dioxide and high temperature, may occur in ponds or during harvest. Therefore, market‐sized Channel Catfish Ictalurus punctatus were acutely exposed (12 hr) to one of the three water quality treatments while confined during a simulated socking procedure and evaluated for stress responses by means of change in blood parameters and fillet quality. In fish subjected to the extreme treatment, hematocrit, plasma cortisol, glucose and lactate levels increased, with 22% mortality, indicating highly stressful conditions. In fish subjected to moderate and typical (control) treatments, cortisol increased but a lack of change or decrease in glucose and lactate indicated minimal anaerobic metabolism. Only one red fillet was produced by the extreme treatment and two by the typical treatment; therefore, the results suggest red fillets are not a product of poor water quality compounded by handling during harvest.  相似文献   

12.
The physiological response of common carp, Cyprinus carpio (L.) to increased stocking density and an additional acute net confinement stressor was investigated. Stocking densities were increased from 28.4 to 56.8 or 113.6 kg m?3 by the use of crowding screens and fish were sampled from the crowded groups after 15, 39 and 87 hours of crowding (hc). A transient elevation of plasma cortisol was found in the higher density group after 15 hc before values returned to control levels. Increased stocking density also increased plasma levels of glucose, free fatty acids (FFA) and lactate during the experimental period. No effect was found on oxygen radical production in the blood, haemoglobin or haematocrit levels, but leucocrit values were lower after 39 hc in both groups. Net confinement resulted in a significant increase in plasma cortisol levels in all groups. However, after 15 hc, cortisol and FFA levels in both crowded plus confinement groups were higher than in the control and confined groups. Confinement resulted in increased oxygen radical production in the crowded plus confined groups at all times. Results indicate that although carp responded with a mild stress response to increased stocking density and adaptation occurred by 87 hc, the crowded fish were more sensitive to an additional acute stressor.  相似文献   

13.
In high intensive fish production systems, hyperoxygenation and reduced flow are often used to save water and increase the holding capacity. This commonly used husbandry practice has been shown to be stressful to fish and increase mortality after infectious pancreatic necrosis virus (IPNV) challenge, but the cause and effect relationship is not known. Salmonids are particularly sensitive to stress during smoltification and the first weeks after seawater (SW) transfer. This work aimed at investigating the impact of hyperoxygenation combined with reduced flow in fresh water (FW), on the intestinal barrier in FW as well as during later life stages in SW. It further aims at investigating the role of the intestinal barrier during IPNV challenge and possible secondary infections. Hyperoxygenation in FW acted as a stressor as shown by significantly elevated plasma cortisol levels. This stressful husbandry condition tended to increase paracellular permeability (Papp) as well as translocation of Aeromonas salmonicida in the posterior intestine of Atlantic salmon. After transfer to SW and subsequent IPNV challenge, intestinal permeability, as shown by Papp, and translocation rate of A. salmonicida increased in the anterior intestine, concomitant with further elevation in plasma cortisol levels. In the anterior intestine, four of five fish displayed alterations in intestinal appearance. In two of five fish, IPNV caused massive necrosis with significant loss of cell material and in a further two fish, IPNV caused increased infiltration of lymphocytes into the epithelium and granulocytes in the lamina propria. Hyperoxygenation and reduced flow in the FW stage may serve as stressors with impact mainly during later stages of development. Fish with an early history of hyperoxygenation showed a higher stress response concomitant with a disturbed intestinal barrier function, which may be a cause for the increased susceptibility to IPNV infection and increased susceptibility to secondary infections.  相似文献   

14.
While the existence of dominance hierarchies within natural populations of salmonids is well known, little is known about the physiological consequences of these social interactions. To investigate such physiological effects, replicate groups of four brown trout (Salmo trutta) were held under simulated natural conditions in an artificial stream tank. Behavioural observations allowed the fish to be ranked for dominance. After two weeks, physiological status was assessed through measurements of specific growth rate, condition factor, plasma cortisol and ion concentrations, haematocrit, leucocrit, hepatosomatic index, hepatic glycogen concentration, interrenal cell nuclear area and gill epithelium chloride cell density. Weight gain in the first-ranking (dominant) fish was significantly higher than in the second-ranking fish. In addition, the condition factor of the second-ranking fish decreased over the experimental period while those of the first- and third- ranking fish increased, resulting in significant differences among the three groups. The only other physiological parameter which varied significantly among the ranked fish was chloride cell density, which was significantly higher in the second-ranking fish than in the dominant fish. Cortisol concentrations were low in all fish and did not vary significantly with dominance status. Overall, the least beneficial position, in physiological terms, appears to be the second rank in the dominance hierarchy.  相似文献   

15.
Many studies have been made about the physio-logical effects of isolated chronic or acute stress. However, few studies have been made to assess the combination of both responses. The fish submitted to chronic stress may be subjected to an additional acute stressor. The aim of the present work was to evaluate the acute stress response in Nile tilapia Oreochromis niloticus (L.) previously subjected to chronic stress. For this, two experiments were performed. In the first experiment, the fish were subjected to chronic stress followed by an additional acute stress. In the second experiment, the fish were submitted only to an acute stress. The data showed that Nile tilapia fingerlings can adapt to chronic stress situations, and this decreases, but does not eliminate, their capacity to respond to an additional acute stressor. In both experiments, plasma cortisol levels reached a peak 1 h after administration of the acute stressor. In fish previously submitted to chronic stress, the highest concentration of plasma cortisol measured was 196 ng mL–1. This value was significantly different from the cortisol concentration obtained in the second experiment (267 ng mL–1) with non-chronically stressed fish. The data also suggest that the chronic stress response can provoke a reduction in performance and growth rates compared with non-stressed fish.  相似文献   

16.
The stress response to dorsal aorta cannulation and serial blood sampling was examined in the channel catfish Ictalurus punctatus. Channel catfish cannulated and repetitively sampled once a day for 7 days did not exhibit a change in response to surgery or to the 24h sample regime as measured by plasma cortisol, glucose, and chloride. In fish that were either serially bled (0, 1, 3, 6, 9, 12, 24, and 48h) immediately after surgery or allowed to recover 6 days before being serially bled, overall plasma cortisol levels were higher than those of fish bled every 24h. Catfish serially bled immediately after surgery had significantly higher plasma glucose levels compared with catfish allowed to recover from surgery 6 days before serial sampling. Although channel catfish recover from cannulation surgery in 24h, a longer recovery period may be needed prior to serial sampling if the samples are taken more frequently than every 24h.  相似文献   

17.
The purpose of this study was to characterize the plasma cortisol response in golden shiners (Notemigonus crysoleucas) under crowding stress, and to determine whether dietary lipid affects the cortisol response. The main differences between the diets were the relative amounts and types of fatty acids of the n-3 and n-6 families. In experiment 1, triplicate groups of golden shiners were fed diets with 4 or 13% menhaden fish oil, or 4 or 13% poultry fat at 3% body weight for 4 weeks before the crowding stress. In experiment 2, fish were fed diets with 8% lipid from soybean oil (SBO), cod liver oil (CLO), (SBO+CLO), or cottonseed oil (CSO) for 6 weeks before the stress test. Plasma cortisol was measured initially, two hours after the stressor was applied, and two hours after the stressor was removed. The overall pattern of the cortisol response was similar to that seen in other warmwater fishes, but the rate and magnitude of the response were not affected by diet in either experiment. Golden shiners have an intermediate cortisol response compared to other fish that have been exposed to similarly stressful conditions.  相似文献   

18.
The aim of the present study was to evaluate the effect of stress and nutritional state (fed vs food deprived) on the generalized stress response and intestinal integrity in Atlantic cod (Gadus morhua L.). Cod in feeding or food deprived states were subjected to 15 min of acute stress (exhaustive exercise). Blood was collected at 9 intervals from before stress (t = 0), to t = 48 h post stress and analysed for blood haematocrit and haemoglobin, and plasma cortisol, lactate, glucose, osmolality, chloride, as well as the tissue damage indicators glutamate oxaloacetate transaminase, glutamate pyruvate transaminase and thiobarbituric acid reactive substances. Intestinal segments were prepared for histology with the same intervals, while assessment of intestinal integrity and microbiology was performed at t = 0, 4 and 48 h post stress.Subjecting cod to exhaustive stress initiated a standard stress response including increased blood Hct and plasma cortisol, glucose, chloride, osmolality and lactate. Food deprived fish did in general have reduced stress resistance compared to fed fish. For many parameters, cod returned slowly to basal levels. Cellular indicators of tissue damage and oxidative stress increased in a biphasic manner following stress. Stress did not affect gut histology but did transiently increase gut permeability. Furthermore, stress had no effect on the adherent bacterial population level in midgut, but did cause a small decrease in hindgut (non-significant) and hindgut chamber (p < 0.05). Isolates belonging to Carnobacterium were predominant but not affected by stress.In conclusion, food deprived cod are less resistant to stress than fed cod. The magnitude of the response is less than in salmonids, but the effects are persistent (including tissue damage indicators and oxidative stress) and may have negative long term consequences. The gut is relatively resistant to stress, there is however a transient increase in the intestinal permeability and alterations in microbiota that may indicate lower protection against invading pathogens.  相似文献   

19.
The effects of metomidate anaesthesia on levels of plasma cortisol, glucose, haematocrit and chloride in Atlantic salmon (1+) (Salmo salar L.), after a 2‐h transport and during a 48‐h recovery period were investigated. The use of metomidate anaesthesia during transport led to a reduced release of cortisol and significantly lower levels of plasma cortisol after a 48‐h recovery period. Plasma glucose did not return to basal level after a 48‐h recovery period, indicating that even longer recovery may be needed for the fish to return to a pre‐stress state. The results show that metomidate anaesthesia combined with a recovery period lessens the stress burden imposed by hauling and transport.  相似文献   

20.
Whole body concentrations of cortisol were determined via radioimmunoassay in chinook salmon, Onchorynchus tshawytscha, during early development in both stressed and non-stressed fish to determine when the corticosteroidogenic stress response first appeared. Progeny from both pooled and individual females were examined to determine if differences existed in offspring from different females. Levels of cortisol were low in eyed eggs, increased at hatch, decreased 2 weeks later and then remained constant thereafter. Differences in cortisol between stressed and control fish were found 1 week after hatch and persisted for the remainder of the study. The magnitude of the stress response, or relative amount of cortisol produced, generally increased from the time when it was first detected, but a decrease in the ability to elicit cortisol was seen 4 weeks after hatching. Cortisol content of separate progeny from two individual females showed a similar pattern to that seen in pooled eggs. Our results indicate that chinook salmon are capable of producing cortisol following a stressful event approximately 1 week after the time of hatching. The decrease in endogenous cortisol content seen 2 weeks after hatching, and the decrease in the magnitude of the stress response seen 4 weeks after hatching may be comparable to developmental events documented in mammals where corticosteroid synthesis is inhibited to neutralize possible detrimental effects of these hormones during critical periods of development. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

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