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1.
Bovine lactoferrin (LF) was evaluated for its ability to suppress stress reactions in carp, Cyprinus carpio L., held under deteriorating environmental conditions. Three test diets containing different levels of LF (0.01, 0.1 and 1%) were fed at 2% of fish body weight per day, i.e. LF at 2, 20 and 200 mg kg(-1) body weight day(-1) was administered orally to carp for 14 days at 20 °C. In the fish reared at a density of 2 individuals 10 l(-1) , plasma cortisol, adrenaline and noradrenaline decreased in the groups fed with 0.1 and 1% LF content diets. In the fish held at a density of 10 individuals 10 l(-1) for 3 days, plasma cortisol, adrenaline, noradrenaline, dopamine and glucose were higher than those at 2 individuals 10 l(-1) in both the control and LF-treated groups. The extent to which these parameters were elevated in the fish held at the same density was reduced with increasing LF content of the diet. Twenty-four hours after exposure to hypoxic conditions (dissolved oxygen level, 2.5 mg l(-1) ), haemoglobin, haematocrit, plasma cortisol, adrenaline, noradrenaline and dopamine increased significantly in all groups. The responses of hypoxic fish fed with 0.1 and 1% LF diets for 14 days were smaller than those of the controls. These results suggest that LF has an ability to reduce the stress response of carp held under deteriorating environmental conditions.  相似文献   

2.
The stress response of coral trout (Plectropomus leopardus ) to wild capture or controlled shallow water stressors was investigated. Stress associated with capture from the wild, handling and transport and shallow water evoked significant changes in circulating levels of cortisol, glucose, lactate, haemoglobin (Hb) and haematocrit (Hct) in coral trout. Plasma glucose, Hb and Hct increased over 30 to 60 min in response to the controlled stressor and then returned toward unstressed levels, even if the stressor persisted. Cortisol increased to maximum levels over the 60 min following the onset of the stressor and remained elevated for 4 h in the case of a single 30 min shallow water event or 3 d in response to the capture, handling and transport. The difference between the responses of blood glucose and cortisol suggests that cortisol does not maintain blood glucose during stress in coral trout. The concentrations of circulating thrombocytes, lymphocytes and granulocytes were also significantly affected by shallow water stress. As lymphocytes and granulocytes are important immune components, reduced concentrations of these cells may explain the increases in disease susceptibility, commonly observed in stressed fish during live transport.  相似文献   

3.
刘小玲 《水产学报》2006,30(4):495-501
本文将土池养殖的黄颡鱼成鱼运往室内实验循环系统驯养，并对鱼的摄食及鱼对日常管理活动的反应、血液皮质醇和血糖、外周血红细胞数量、外周血白细胞百分比和吞噬功能进行了35 d的观察或监测。运输后的黄颡鱼在最初4～7 d内，明显的行为变化是停止摄食。所有的鱼从第8天开始恢复了摄食，从第15天开始适应了日常管理活动。血液皮质醇和血糖浓度在刚刚运抵实验循环系统（0 d）及驯养1、2、3 d的鱼体内显著升高，至第7天已显著下降，并在第21、28、35天稳定在低水平上。外周血红细胞数量没有显著变化。与第21、28、35天外周血白细胞的各参数值相比，淋巴细胞百分比在第3、7天显著减少，嗜中粒细胞百分比在0、1、2、3天显著升高，吞噬细胞吞噬百分比和吞噬指数在第7、14天显著降低。以上结果显示（1）运输使黄颡鱼成鱼产生典型的应激反应，（2）运输应激导致黄颡鱼成鱼外周血淋巴细胞和嗜中粒细胞百分比的显著改变和外周血白细胞吞噬功能的抑制，（3）运输应激后的池养黄颡鱼成鱼在本文使用的实验循环系统中充分恢复和驯化所需的最少时间是3周。  相似文献   

4.
Understanding how gilthead sea bream, Sparus aurata L., an important Mediterranean Sea species for aquaculture, respond physiologically to stressors commonly encountered in intensive rearing is important for effective production, as managing for stress is a major factor in maintaining healthy fish stocks. Our objective was to determine whether holding juvenile gilthead sea bream at a high density (HD), as a chronic stressor, would affect their physiological responses to a subsequent acute handling stressor. After acclimation at a low density (LD) of 6 kg m?3 in 200‐L circular tanks containing 33–36 g L?1 recirculating seawater at 19°C under a normal photoperiod, juvenile 37‐g gilthead sea bream were confined for 14 days at a HD of 26 kg m?3 and then subjected to 30‐s aerial emersion in a dipnet. Plasma levels of cortisol, glucose, lactate, osmolality and chloride were determined in fish held in separate lots during LD (control) and HD confinement at 0, 1, 2, 7 and 14 days, and then after handling at 0, 1, 2, 4 and 8 h. Although plasma cortisol levels were similar in LD and HD fish groups after 14 d of confinement (15 and 23 ng mL?1, respectively), the cortisol response in fish from the HD treatment at 1 and 2 h following acute handling (70 and 37 ng mL?1, respectively) was only about half of that measured in the control group (139 and 102 ng mL?1); plasma cortisol was similar in both groups by 4 and 8 h. In contrast, plasma glucose elevations in response to handling were higher at 4 and 8 h in the HD‐held fish (94 and 72 mg dL?1, respectively) than in those from the LD treatment (59 and 51 mg dL?1); glucose responses were similar in both groups at 1 and 2 h after handling and throughout confinement. Plasma lactate levels were higher in LD fish than in the HD group at the beginning of the experiment but were similar after 14 d confinement and responses to handling were similar (e.g. 33 and 35 mg dL?1 at 1 h). Plasma osmolality showed increases during the first 2 h after acute handling but no differences were evident between the two density treatments at any time during confinement or posthandling. Plasma chloride levels did not change throughout the experiment. The reduced plasma cortisol response to acute handling likely resulted from negative feedback of mildly but chronically elevated circulating cortisol caused by the confinement stressor on the hypothalamic–pituitary–interrenal axis. While other post‐handling physiological changes also showed differences between treatment groups, the suppressed cortisol response in the HD‐held fish suggests a reduction in the gilthead sea bream's normal capacity to respond to an acute stressor.  相似文献   

5.
Great sturgeon Huso huso juveniles (sub-yearling; 30–268 g) and adults (12.2 kg) were exposed to different kinds of stressors that are commonly observed in aquaculture practices including density, severe confinement, handling, and sex identification. Blood was taken pre- and post-stress for the measurement of cortisol and glucose concentrations. Results showed that in most cases, primary (cortisol) and secondary (glucose) responses of fish to stressors significantly increased. Some different responses were observed between low and high densities as well as male and female. In many cases, stress metabolites decreased to the initial levels at 9–12 h after stress. Results revealed that responses to the stressors in sturgeon are not high as like as teleosts. We established that acute stressors cause a stress response in different size classes of great sturgeon. We characterized the resting profile for cortisol and determined the dynamics of this hormone as well as under simulated management stressors. With this information, we can start the development of management practices (such as anesthesia and appropriate density and handling) that would eliminate stressors interfering with production performance and well-being of the animal in aquaculture. To achieve this, potential stressors should be avoided and possible procedures and techniques can be used or modified to reduce the degree of stress on the fish as much as possible.  相似文献   

6.
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   

7.
Hybrid seabream (Pagrus major♀ × Acanthopagrus schlegelii♂) grow quickly, with retarded gonadal growth and enhanced muscle nutritional composition. This F1 hybrid seabream is a new marine aquaculture fish in China. However, the response of hybrid seabream to transport is severe, which seriously restricts its promotion and development. Water quality and the physiological response of hybrid sea bream were studied at three fish transport densities (5, 10 and 20 g/L) during 8 hr of transport in a light van (60 km hr?1 and 25°C water temperature). We found that total ammonia–nitrogen and nitrite–nitrogen levels in the water of the highest density group increased sharply after 4 and 8 hr of transport. Cumulative survival of the fish in the 10 and 20 g/L groups (86.7% and 75% respectively) was significantly lower than in the 5 g/L group (100%) after 8 hr of transport (p < .05). Serum cortisol and lactate levels were significantly higher after transport than pre‐stress levels, whereas the glucose level decreased significantly (p < .05). Hepatic triglyceride and glycogen levels and superoxide dismutase and catalase activities were significantly lower in the 20 g/L group than in the 5 g/L group (p < .05). The results show that high‐density transport increased ammonia–nitrogen and nitrite–nitrogen levels in the water as well as cortisol secretion and anaerobic metabolism in the F1 hybrid seabream, suggesting that total cholesterol and glycogen may be used to supply the energy demand and increased oxidative stress. These results will help to optimize the transport conditions for cultured hybrid seabream.  相似文献   

8.
The purpose of this study was to determine the effect of AQUI‐S® (5.0 mg/L) sedation compared with nonsedation on the primary (plasma cortisol), secondary (osmoregulation), and tertiary (mortality) stress responses in Atlantic salmon smolts during transport and transfer to sea. AQUI‐S sedation during on‐ and off‐loading sufficiently reduced the primary stress response to lower mortality (2.5%) during transfer to sea compared with unsedated fish, which experienced a mortality rate above 11.5%. The unsedated fish experienced an acute mortality, which only stabilized 16 d after the transport. None of the secondary stress responses measured in this experiment could contribute in explaining this phenomenon, with the possible exception of plasma magnesium. While osmolality and chloride increased in both groups during the experiment, it did not seem to be related to the difference in the primary stress response documented in the sedated and unsedated groups. It instead appeared to be an effect of the salinity change from freshwater to seawater after transport. Plasma magnesium differed between the groups, while plasma magnesium in the AQUI‐S‐sedated group returned to prestress levels 12 h after transport. The unsedated group showed no such recovery even 1 wk after transport, which may indicate a disturbance in hydromineral balance and give plausible explanation for delayed mortality this group experienced. AQUI‐S shows promise as a stress‐reducing sedative for Atlantic salmon smolts and if used properly could improve animal welfare and survivability during and after common aquaculture‐related incidents.  相似文献   

9.
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   

10.
Anaesthesia of farmed fish: implications for welfare   总被引：1，自引：0，他引：1  
During their life cycle as farmed animals, there are several situations in which fish are subjected to handling and confinement. Netting, weighing, sorting, vaccination, transport and, at the end, slaughter are frequent events under farming conditions. As research subjects, fish may also undergo surgical procedures that range from tagging, sampling and small incisions to invasive procedures. In these situations, treatment with anaesthetic agents may be necessary in order to ensure the welfare of the fish. The main objective of this paper is to review our knowledge of the effects of anaesthetic agents in farmed fish and their possible implications for welfare. As wide variations in response to anaesthesia have been observed both between and within species, special attention has been paid to the importance of secondary factors such as body weight, water temperature and acute stress. In this review, we have limited ourselves to the anaesthetic agents such as benzocaine, metacaine (MS-222), metomidate hydrochloride, isoeugenol, 2-phenoxyethanol and quinaldine. Anaesthetic protocols of fish usually refer to one single agent, whereas protocols of human and veterinary medicine cover combinations of several drugs, each contributing to the effects needed in the anaesthesia. As stress prior to anaesthesia may result in abnormal reactions, pre-anaesthetic sedation is regularly used in order to reduce or avoid stress and is an integral part of the veterinary protocols of higher vertebrates. Furthermore, the anaesthetic agents that are used in order to obtain general anaesthesia are combined with analgesic agents that target nociception. The increased use of such combinations in fish is therefore included as a special section. Anaesthetic agents are widely used to avoid stress during various farming procedures. While several studies report that anaesthetics are effective in reducing the stress associated with confinement and handling, there are indications that anaesthesia may in itself induce a stress response, measured by elevated levels of cortisol. MS-222 has been reported to elicit high cortisol release rates immediately following exposure, while benzocaine causes a bimodal response. Metomidate has an inhibitory effect on cortisol in fish and seems to induce the lowest release of cortisol of the agents reported in the literature. Compared to what is observed following severe stressors such as handling and confinement, the amount of cortisol released in response to anaesthesia appears to be low but may represent an extra load under otherwise stressful circumstances. Furthermore, anaesthetics may cause secondary adverse reactions such as acidosis and osmotic stress due to respiratory arrest and insufficient exchange of gas and ions between the blood and the water. All in all, anaesthetics may reduce stress and thereby improve welfare but can also have unwanted side effects that reduce the welfare of the fish and should therefore always be used with caution. Finally, on the basis of the data reported in the literature and our own experience, we recommend that anaesthetic protocols should always be tested on a few fish under prevailing conditions in order to ensure an adequate depth of anaesthesia. This recommendation applies whether a single agent or a combination of agents is used, although it appears that protocols comprising combinations of agents provide wider safety margins. The analgesic effects of currently used agents, in spite of their proven local effects, are currently being debated as the agents are administrated to fish via inhalation rather than locally at the target site. We therefore recommend that all protocols of procedures requiring general anaesthesia should be complemented by administration of agents with analgesic effect at the site of tissue trauma.  相似文献   

11.
The purpose of this study was to determine the effect of clove oil (4.0 mg L−1) sedation, compared with non-sedation, on the primary (plasma cortisol), secondary (osmoregulation) and tertiary (mortality) stress responses in Atlantic salmon smolts during transport and transfer to sea. Clove oil sedation during on- and off-loading sufficiently reduced the primary stress response to lower mortality (2.1%) during transfer to sea compared with unsedated fish, which experienced a mortality rate above 12.2%. The unsedated fish experienced an acute mortality that stabilized only 6 days after the transport. None of the secondary stress responses measured in this experiment could contribute towards explaining this phenomenon, with the possible exception of plasma magnesium (Mg2+). Plasma Mg2+ differed between the groups; while plasma Mg2+ in the clove oil sedated group returned to pre-stress levels 72 h after transport, the unsedated group showed no such recovery even 1 week after transport, which may indicate a disturbance in the hydromineral balance, and provides a plausible explanation for the delayed mortality in this group. Eugenol-based anaesthetics appear to be promising as a stress-reducing sedative for Atlantic salmon smolts, and, if used properly, this chemical could improve animal welfare and survivability during and after common aquaculture-related incidents.  相似文献   

12.
Successive exposure to aquaculture‐related stressors may compromise the allostatic capacity of African catfish and lead to allostatic overload and poor welfare. Therefore, we tested the effect of (i) feeding during the light or dark phase, (ii) density (51 fish per 140 L versus 51 fish per 43 L) and (iii) altered available resting space/shelter on stress handling were studied in African catfish (Clarias gariepinus). Available resting space/shelter was manipulated by providing PVC‐tubes in the tanks. Growth, baseline stress load (cortisol and osmolality), metabolism (glucose, lactate and non‐esterified fatty acids) and aggression (measured by skin scar incidence) were assessed. Upon completion of the experimental period, we determined the adaptive capacity of the fish by the response to air exposure. We show that night‐feeding enhances growth and lowers feed conversion ratio compared to day‐feeding. No effects of density were found for baseline stress hormones, basal metabolism or aggression. Low density seems to stimulate aggressive behaviour after air exposure. Unexpectedly, providing PVC‐tubes under high‐density conditions increased aggression, raised baseline cortisol levels and decreased basal metabolism as well as growth; also the endocrine response to air exposure was stronger. We argue that these effects relate to a reduction in available space, i.e. a further increase in density, or to an increased competition for shelter. Overall, our data suggest that night‐feeding optimizes growth and that care should be taken in using objects as shelter/enrichment for African catfish.  相似文献   

13.
Methods were developed to assess whole‐body immunoreactive corticosteroid concentrations (IRC) and plasma levels of cortisol in Atlantic cod subjected to several common, acute stressors. A measurable corticosteroid stress response was observed at the first sampling in whole bodies of 8‐day post‐hatch (dph) larvae. Two groups of juveniles (～5 and 30 g) were subjected to a 30 s net stressor and whole‐body IRC and plasma cortisol levels were determined. Post‐stressor IRC in smaller fish rose approximately 14‐fold, peaked at 1 h, were sustained for 3–6 h and returned to pre‐stressor levels within 24 h. Post‐stressor plasma cortisol levels in larger fish rose approximately 18‐fold, peaked at 0.5–1 h, were sustained for 1–3 h and then returned to near pre‐stressor levels after 24 h. Immunoreactive corticosteroid concentrations appeared to remain elevated longer than plasma cortisol levels suggesting that steroids other than cortisol were contributing to total immunoreactivity in homogenates. Juveniles exposed to either a grading procedure or high density transport had maximal IRC and plasma cortisol levels within 90 min which returned to pre‐stressor levels within 24–72 h. A reduction in water salinity (20 g L?1) did not moderate the corticosteroid response in juveniles. The results show that Atlantic cod respond to common, acute stressors in a manner similar to other teleosts. Whole‐body homogenates can be used to identify changes in IRC in response to acute stress in cod with the caveat that recovery IRC may differ from plasma cortisol concentrations.  相似文献   

14.
本研究选取乌鳢(Channa argus)和南方大口鲶(Silurus soldatovi meridionalis)为捕食者,青鱼(Mylopharyngodonpiceus)、草鱼(Ctenopharyngodonidellus)、鲢(Hypophthalmichthysmolitrix)、鳙(Aristichthys nobilis)幼鱼为猎物鱼,比较了在无捕食(空白对照)、低捕食(隔网胁迫)和高捕食(直接胁迫)压力下,胁迫0、7、14d后,“四大家鱼”幼鱼血清皮质醇(COR)水平和血液生化指标的变化。结果显示,不同捕食胁迫水平下,“四大家鱼”幼鱼的血液生化指标和COR水平变化程度不同,但变化趋势一致。“四大家鱼”幼鱼的COR水平随着捕食胁迫程度和胁迫时长的增加显著升高,表现为无捕食组<低捕食组<高捕食组,0 d<7 d<14 d。在血液生化指标中,血清蛋白浓度和总胆固醇(CHO)浓度较为稳定,各组相比无显著变化;血糖(GLU)浓度和碱性磷酸酶(ALK)在捕食胁迫下升高,甘油三酯(TG)则相反,呈下降趋势。研究表明,“四大家鱼”幼鱼会根据捕食风险来增强自身...  相似文献   

15.
曹杰  王琪  梅俊  谢晶 《水产学报》2021,45(7):1034-1042
为探究大菱鲆分别在有水及无水条件下运输过程中生理生化指标及肌肉品质的变化,为大菱鲆的保活运输提供参考。将大菱鲆进行暂养、降温、充氧包装后进行模拟运输,并在运输不同时间段取样,检测大菱鲆生理生化指标及肌肉指标。结果显示,模拟运输18 h后,有水运输组和无水运输组中的大菱鲆存活率仍为100%。大菱鲆肌肉中水分含量、粗脂肪、pH、糖原、三磷酸腺苷(ATP)和腺苷酸(AMP)含量显著降低,乳酸和肌苷酸(IMP)含量升高。其中,有水运输组中的大菱鲆AMP含量降低了38.65%,IMP含量增加了29.1%,无水运输组中的大菱鲆AMP含量降低了12.83%,IMP含量增加了28.47%。大菱鲆血液生化指标中,葡萄糖、尿素氮和皮质醇含量显著升高。运输过程后,无水运输组中大菱鲆生理应激及能量代谢指标的变化幅度均小于有水运输处理组中的大菱鲆。此外,低温无水运输组大菱鲆肌肉中呈味核苷酸IMP和AMP含量显著高于有水运输组,表明低温无水运输增加了大菱鲆呈鲜味物质的含量,提高了鱼肉风味。研究表明,低温无水保活技术在活鱼运输中具有广泛的应用前景。  相似文献   

16.
The objective of this experiment was to test the efficacy of a probiotic (Efinol®L) during transportation of marbled hatchetfish, Carnegiella strigata . Wild specimens were captured from a small stream and transported for 24 h in plastic fish boxes with a probiotic (10 mg L−1) and probiotic-free water. The boxes were sampled at 3, 12 and 24 h of transport. At the end of the experiment, the survival rate was close to 100% in both treatments. Dissolved oxygen diminished with time in both treatments, but the probiotic group had significantly higher levels. Conductivity, pH and ammonia increased significantly during the transport, demonstrating higher levels in the probiotic-free group. Fish from both treatments presented very high net Na+ and K+ effluxes after 3 h of transport. At 24 h, net K+ effluxes in fish of the probiotic treatment reached values close to zero and a significantly lower Na+ efflux was observed. Cortisol levels in both treatments at 3 and 12 h were significantly higher than that in control samples. Higher body cortisol levels were observed in the probiotic-free group than that in the probiotic group at 3 and 12 h. The results demonstrate that addition of a probiotic during fish transport improves water quality and leads to fish presenting a lower stress response intensity.  相似文献   

17.
There is a growing commercial interest in the fish, Puntius filamentosus , in the ornamental fish trade in India and elsewhere. The trade is, however, hampered by severe mortalities during transport of the fish owing to insufficient data available on the use of anaesthetics. To resolve this problem, we evaluated the efficacy of two anaesthetics, MS-222 and benzocaine, in sedating P. filamentosus in simulated transportation experiments and used stress response parameters such as cortisol and blood glucose levels to perform assessments. We observed that MS-222 at 40 mg L−1 and benzocaine at 20 mg L−1 were sufficient to induce sedation for 48 h. Above these concentrations, both the anaesthetics adversely affected the fish and resulted in mortalities. Both anaesthetics significantly lowered the blood cortisol and glucose levels compared with the unsedated controls. Importantly, the anaesthetics treatment significantly lowered the post-transport mortality in the fish. The results of the study show that MS-222 and benzocaine could be used as sedatives to alleviate transport-related stress in P. filamentosus to improve their post-transport survival and hence reduce economic loss.  相似文献   

18.
Current ornamental fish packaging systems are characterized by very high fish loading densities and high metabolic wastes in the transport water after shipment. They focus mainly on management of the quality of transport water. Recent studies using the guppy as a model fish showed that post‐shipment mortality could be reduced through enhancement of the stress resistance of the fish, and hence emphases should also be placed on the preparation of the fish for transport and recovery of the fish after shipment. Farmers can contribute significantly by applying nutritional prophylaxis before harvesting. Exporters may use the salinity stress test to identify fish lots of good quality for transport, apply health prophylaxis to eradicate parasites and optimize other techniques such as starvation of the fish or addition of salt to the transport water to enhance the stress resistance of the fish. Importers may adopt proper acclimation procedure and allow fish to recover in low salinity water to reduce post‐shipment mortality. As the main bulk of post‐shipment mortality is stress‐mediated and occurs during the 1‐week recovery period, the industry should consider revising the basis of the current warranty system for their customers, from death on arrival to cumulative mortality at 7 days post shipment (or death after 7 days, DA7), in order to cut down fish losses after shipment.  相似文献   

19.
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   

20.
As the most popular baitfish in the USA, the golden shiner is subjected to frequent handling and transportation episodes prior to retail marketing and recreational use. Considerable mortality and economic loss can occur during handling and transportation. Limited information is available concerning stress responses, such as cortisol secretion, and mobilization of nutrients, such as zinc and ascorbic acid, during handling and transportation of this fish species. Therefore, two concurrent experiments were performed to characterize cortisol responses, as well as changes in whole‐body zinc and visceral ascorbic acid concentrations, after harvesting, grading, and transporting by ground or air. During ground transportation, fish were sampled immediately after being subjected to the following conditions: seined from a commercial pond in Lonoke, Arkansas (I), released into vats from the loading truck (II), graded by bar grader (III), loaded onto a hauling truck (IV) and after transport for 10 h to Brenham, Texas (V). Fish were also sampled before and after air freight shipment. Whole‐body cortisol appeared to be a reliable endocrine marker for stress response of golden shiner subjected to handling and transportation. Grading by bar grader was the most stressful event in the process of handling and transporting golden shiners, resulting in a significantly elevated whole‐body cortisol concentration of 107 ng/g tissue, compared to concentrations of 6.3, 32.3, 15.7, and 30.4 ng/g tissue, for stages I, II, IV, and V, respectively. A significant increase in whole‐body cortisol concentration was also observed after air transportation of 22 h duration. No significant reductions in whole‐body zinc or visceral ascorbic acid concentrations were observed.  相似文献   

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