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1.
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   

2.
The aim of the present study was to evaluate the potential effects of olive leaf (Olea europea L.) extract (OLE) on common carp (Cyprinus carpio) health in response to ambient ammonia toxicity. Fish were fed with experimental diets containing OLE (0, 1, 5 and 10 g/kg) for 60 days followed by a 3‐hr challenge with ammonia (0.5 mg/L unionized ammonia‐N). Results showed that haemoglobin levels, differential leucocyte counts and mean corpuscular haemoglobin concentration were not affected by dietary OLE levels and ammonia challenge. Ammonia challenge significantly increased red blood cells and decreased blood mean corpuscular volume, mean corpuscular haemoglobin, plasma lysozyme, complement and bactericidal activities. Plasma lysozyme, complement and total immunoglobulin values improved by 5 and/or 10 g OLE/kg supplementation. Before the ammonia exposure, the 5 and 10 g OLE/kg treatment significantly increased blood white blood cell, but there was no significant difference among the treatments after the ammonia exposure. Ammonia exposure significantly increased plasma malondialdehyde levels; however, 1 and 5 g OLE/kg treatments had significantly lower values compared to the other treatments. The present results suggest that 1 g OLE/kg diet may improve fish health and reduce the adverse effects of ammonia toxicity on common carp.  相似文献   

3.
任洪涛  林霖 《水产科学》2016,(6):644-648
在水温(20±1)℃下,采用静水测试法研究水体中不同质量浓度Cr6+(120.00、160.80、215.47、288.73、386.90mg/L,重铬酸钠配制)对体质量约10g草鱼脑和肝胰脏的组织结构及肝胰脏中超氧化物歧化酶活性的影响,以探讨重金属的毒性积累和毒性机制。试验结果表明,Cr6+对草鱼的24、48、96h半数致死质量浓度(LC50)分别为302.77、154.47、78.89mg/L,由(48hLC50×0.3)/(24h LC50/48hLC50)2和96hLC50×0.1计算出安全质量浓度分别为12.068mg/L和7.489mg/L。中毒初期肝细胞轻微肥大,无序离散,细胞核相对缩小,胞浆轻微展出;随着时间的延长,肝胰脏异常的程度更加严重,甚至肝坏死,肝细胞明显肥大,无序性离散程度明显增大,细胞核明显缩小,肝细胞胞浆展出,细胞空化;脑细胞开始出现破裂,细胞液溢出,细胞核轻微聚集;随后脑细胞的异常程度更加严重,细胞破裂、细胞核聚集程度严重。随着Cr6+质量浓度的升高和时间的延长,草鱼肝胰脏中超氧化物歧化酶活性降低。  相似文献   

4.
The aim of this study was to evaluate different ionic adjustment strategies in oligohaline water on the growth of Litopenaeus vannamei and C:N:P stoichiometric ratios of the floc microbial community (MC) in synbiotic nursery system. A 35-day culture (2000 PL's/m3) was carried out in 60 L units in a completely randomized experimental design, with three treatments: T1—seawater diluted to a salinity of 2.5 g/L (control), T2—water with a salinity of 2.5 g/L with potassium (K?) adjusted and T3—water at a salinity of 2.5 g/L with its Ca:Mg:K ratio adjusted to 1:3:1, each treatment in triplicates. The MC of flocs and the dissolved fraction (DF) was separated by filtration, where MC >1.6 µm and DF <1.6 µm. The juveniles reached a final weight of 0.40 ± 0.09–0.49 ± 0.04 g, survival above 80% and an average yield of 0.69 ± 0.18–0.81 ± 0.02 kg/m3, without significant differences among the treatments. A stabilizing trend of C:P, C:N and N:P ratios of MC was observed considering the variations of C:N:P in the DF, indicating a homeostatic behaviour of the floc MC, as occurs in systems with high nutrient availability. Our results indicate that the major ions initial concentrations (Ca2+: 25.07 mg/L, Mg2+: 89.75 mg/L and K?: 25.00 mg/L), total alkalinity 100.00 mg/L and total hardness 433.30 mg/L provide conditions that do not limit shrimp growth in oligohaline water synbiotic nursery system.  相似文献   

5.
This study investigated the secondary stress responses of Paralichthys orbignyanus exposed to ammonia and nitrite and after recovery. Fish were exposed to 0.12, 0.28, and 0.57 mg NH3‐N/L, or 5.72, 10.43, and 15.27 mg NO2‐N/L for 10 d followed by the same time length for recovery. Ammonia‐ and nitrite‐free water was used as a control treatment. Blood samples were collected after 1, 5, and 10 d of exposure and after recovery. Fish exposed to ammonia presented lower and higher glucose levels after 10 d of exposure and recovery, respectively. Ammonia induced initial and transient ionic disturbances and metabolic alkalosis. Nitrite exposure caused hyperglycemia, increased plasma K+ levels, and respiratory alkalosis, whereas metabolic acidosis was observed after recovery. Increased proportion of monocytes and/or granulocytes and reduced number of lymphocytes were demonstrated in fish exposed to 0.28 mg NH3‐N/L (Day 1) and 10.43 mg NO2‐N/L (Day 5) and after recovery in the 0.28 and 0.57 mg NH3‐N/L treatments. Exposure to ammonia decreased the proportion of granulocytes on Day 5. In conclusion, exposure to concentrations at 0.12 mg NH3‐N/L and 5.72 mg NO2‐N/L provoked physiological disorders in Brazilian flounder. Nonetheless, fish exposed to 5.72 mg NO2‐N/L following a 10‐d recovery period showed complete resumption of homeostasis.  相似文献   

6.
Skin mucus has been demonstrated to provide stress biomarkers for evaluating the physiological status, providing new convenient and non‐invasive methods to detect stress response in fish. Here, we investigated the anaesthetic efficacy of tricaine methanesulphonate (MS‐222; 75–115 mg/L) for discus Symphysodon aequifasciata (34.27 ± 4.46 g; 8.10 ± 0.59 cm) using skin mucus stress biomarkers. The induction time, recovery time and respiratory frequency were also determined. According to the criteria for anaesthesia and recovery, discus fish to reach stage A3 (deep anaesthesia) within 3 min and to reach stage R4 (full recovery of normal behaviour) within 5 min were observed at 95–105 mg/L MS‐222. Respiratory frequency increased first and then decreased during MS‐222 exposure and increased after recovery. At 10 min after deep anaesthesia, a lower mucus glucose was only observed at 115 mg/L MS‐222. No change in mucus cortisol and increased lactate were observed in all treatments. Increased mucus protein was observed at 75, 85 and 95 mg/L MS‐222. At 10 min after recovery, increased mucus glucose and decreased mucus protein were observed at 85, 95 and 115 mg/L MS‐222, but increased mucus cortisol only at 115 mg/L and lactate only at 75 and 105 mg/L MS‐222. At 24 hr after recovery, mucus glucose returned to the initial level only at 75, 95 and 105 mg/L MS‐222, while cortisol at 75 and 85 mg/L and protein and lactate at 75 mg/L respectively. Overall, the effective dose of MS‐222 for discus fish has been suggested to be 95–105 mg/L.  相似文献   

7.

The use of recombinant gonadotropin-releasing hormone (rGnRH) has very rarely been tested in fish to promote spawning. This study evaluated the impact of recombinant chicken gonadotropin-releasing hormone (rcGnRH) with metoclopramide on the release of sex steroids and final maturation induction in goldfish (Carassius auratus) broodstock. For this purpose, goldfish broodstock was divided into four groups and treated with 0.9% NaCl with 20 mg/kg metoclopramide (Met) (C); 10 μg/kg body weight (BW) rcGnRH with 20 mg/kg metoclopramide (rcGn10); 15 μg/kg BW rcGnRH with 20 mg/kg metoclopramide (rcGn15); and 20 μg/kg BW rcGnRH with 20 mg/kg metoclopramide (rcGn20). The capability of the rcGnRH for eliciting biological response was tested in vivo by evaluating the changes of 17β estradiol (E2), testosterone (T), and 17α, 20β-dihydroxy-4-pregnen-3-one (DHP) and the induced spawning. Blood samples were obtained at 0 h, 12 h, and 24 h after injection. The rcGn10, rcGn15, and rcGn20 treatments induced lower E2 concentration, especially 24 h post-injection. T levels were significantly higher in rcGn10, rcGn15, and rcGn20 treatments 12 h post-injection than at 0 h and then decreased at 24 h post-injection. Furthermore, the rcGnRH tested significantly enhanced DHP secretion in rcGn10, rcGn15, and rcGn20 treatments 12 h post-injection before a decline at 24 h post-injection. No significant difference between the sampling times was found in the C treatment for the 3 sex steroids tested. The results also displayed that rcGnRH at 10–20 µg/kg of body weight can trigger spawning with the highest speed and efficiency of spawning at 20 µg/kg. The obtained results represent a possible strategy for enhancing the artificial reproduction and ovulation of broodstock fish by rGnRH and further support the use of recombinant hormones to promote reproduction in aquaculture.

  相似文献   

8.
The objective of this study was to evaluate the effect of the addition of Navicula sp. on the growth and fatty acids profile of Litopenaeus vannamei postlarvae in a biofloc system (BFT). Four treatments were used: BFT; BFT 2.5N (addition of 2.5 × 104 cells/ml of Navicula sp.); BFT 5N (addition of 5 × 104 cells/ml of Navicula sp.) and BFT 10N (addition of 10 × 104 cells/ml of Navicula sp.), all in triplicate. The shrimp (1 ± 0.01 mg) were stocked at a density of 3,000 postlarvae/m3 and fed with commercial feed. The diatom was added every 10 days, and at the end of 42 days, shrimp performance, water quality and proximal composition were evaluated. The BFT 5N and BFT 10N treatments had higher performance values, highlighting the values of productivity (2.30 and 2.42 kg/m3) and specific growth rate (15.92 and 16.08%/day), which were higher than the other treatments. In addition, the highest levels of fatty acids were observed in treatments with diatom (BFT 5N and BFT 10N), indicating the benefits of Navicula sp. on growth enhancement and fatty acid content of L. vannamei postlarvae grown in biofloc systems.  相似文献   

9.
A study was conducted to assess the effects of common carp and the African catfish on growth and reproduction of the native tilapia Oreochromis shiranus in Malawi. The study was done from 1 May to 1 October 2018 at the National Aquaculture Centre (NAC), Zomba. Four triplicated treatments were used: O. shiranus + carp (T1), O. shiranus + catfish (T2), O. shiranus + carp + catfish polyculture (T3) and O. shiranus monoculture (T4). Fish were stocked at uniform density of 0.8 fish/m2. Data collection was done once every month. Results showed that O. shiranus mean weight gain (%), specific growth rate (% body weight/day), average daily gain (g fish?1 day?1) and condition factor (g/cm3) were highest in T3 and lowest in T1 and T4 treatments. T3 had better water quality regime and higher tilapia biomass than T1 and T4 treatments. Tilapia fry production (no. fry pond?1 day?1) was highest in T4 but did not significantly differ (p > .05) between T2 and T3 treatments. It is concluded that the farming of common carp in aquatic ecosystems containing the African catfish may not adversely affect growth and reproduction of O. shiranus and that the polyculture of the African catfish, common carp and tilapia can be adopted to mitigate the potential adverse effects of carp on the environment and improve tilapia growth.  相似文献   

10.
任洪涛 《水产科学》2016,(4):415-419
水温(20±1)℃,采用静水测试法研究了养殖水体中不同质量浓度Zn2+(0、9.52、13.14、18.30、25.02、34.53mg/L)对体质量约10g的草鱼脑和肝胰脏的组织结构及肝胰脏中超氧化物歧化酶活性的影响,探讨重金属的毒性积累和毒性机制。试验结果表明,Zn2+对草鱼的24、48h和96h半致死质量浓度分别为23.058、19.317、10.155mg/L,由公式(48hLC50×0.3)/(24hLC50/48hLC50)2和96hLC50×0.1计算出安全质量浓度分别为4.068mg/L和1.0155mg/L。中毒初期草鱼脑细胞轻微聚集,细胞核微增大;随时间延长脑异常加重,细胞聚集明显,核增大几乎充满整个脑细胞;肝胰脏细胞膨大,离散,核缩小,胞浆轻微溢出,少数肝胰脏细胞胞浆溢出,残留的核物质散乱分布,肝胰脏细胞凝固性坏死。随着Zn2+质量浓度的升高和时间延长,草鱼肝脏中超氧化物歧化酶活性降低。  相似文献   

11.
Rainbow trout Oncorhynchus mykiss and mirror carp Cyprinus carpio were slaughtered by either percussion or asphyxiation. For determination of the physical (texture value) and biochemical quality attributes [pH, lactic acid, total volatile basic nitrogen (TVB-N), and malondialdehyde (MDA) values] of trout and carp, the fish were filleted immediately (within 2 h), 12 h after harvest (pre-rigor), 24 and 36 h after harvest (in-rigor), and finally 48 and 60 h after harvest (post-rigor). For microbiological quality attribute (mesophilic and psychrophilic bacteria count) analyses, the fish were filleted immediately (within 2 h) after harvest (pre-rigor), 24 h after harvest (in-rigor) and 48 and 72 h after harvest (post-rigor). By percussion slaughtering followed by pre-rigor filleting, it was possible to process rainbow trout and mirror carp without inflicting excessive handling stress. Percussion slaughter delayed onset of rigor and the percussion-slaughtered fish exhibited a long pre-rigor period (≈24 h), giving plenty time for pre-rigor processing. Percussion slaughtering and pre-rigor filleting of fish was considered to be superior to the traditional asphyxiation slaughtering with respect to texture, TVB-N and MDA attributes.  相似文献   

12.
The aim of this study was to determine the biochemical and histopathological effects of indoxacarb on an economic fish species Cyprinus carpio. The fish were divided into four triplicated groups exposed to either of 0% (control), 5% (0.75 mg/L), 10% (1.5 mg/L) or 20% (3 mg/L) of the pesticide LC50. Blood sampling was performed after 7, 14 and 21 days exposure. There were no changes in blood calcium levels at any times. In the indoxacarb‐treated fish, chloride levels decreased at the first and increased at the second sampling compared to the control. In 3 mg/L treatment, phosphorus increased significantly after 7 days compared to the control. Plasma glucose levels decreased significantly at the 7th and 14th days sampling; however, it increased at the 21st day. After 7 days, creatinine level in 3 mg/L treatment was significantly lower than the control; however, the creatinine levels of indoxacarb treatments were higher than the control at the 21st day. The indoxacarb‐treated fish had higher plasma urea levels compared to the control at the 7th day. At the 21st day, plasma urea level at 3 mg/L was significantly lower than the control treatment. Edema, Lamellar curling, hyperplasia, lamellar fusion and hyperaemia were observed in the indoxacarb‐treated fish gill. Tubular necrosis, hematopoietic necrosis, melanomacrophage aggregates, Bowman's capsule edema, glomerulus degeneration and hyperaemia were observed in the indoxacarb‐treated fish kidney. Generally, sublethal concentrations of indoxacarb cause stress, hydromineral imbalance, metabolism alteration and gill and kidney damages in common carp.  相似文献   

13.
The effect of photoperiod and tank colour on the survival and growth of juvenile seahorse Hippocampus reidi was investigated in the first 15 days after release (DAR). In the first experiment, newly released seahorses were exposed to six photoperiods – 6 h of light (L):18 h of darkness (D), 10L:14D, 12L:12D, 14L:10D, 18L:6D and 24L:0D. In the second experiment, juveniles were kept in tanks of different background colours – blue, white, black, clear and red. No significant differences were observed in the growth and survival among seahorse subjected to 10–24 h of light (P > 0.05). At the end of 15 DAR, fish exposed to 6L:18D showed lower growth in height and weight compared to other treatments (13.8 mm vs. 20.0–22.2 mm and 13.4 mg vs. 37.2–43.2 mg respectively) and lower survival (80% vs. 88–95% respectively). Tank colour did not affect growth and survival of juveniles up to 15 DAR.  相似文献   

14.
在水温(22±2)℃条件下,将平均体质量约为100 g的健康草鱼、花鲈、鲫鱼在50 mg/L的间氨基苯甲酸乙酯甲磺酸盐(MS-222)药液中浸泡,分别于药浴0.5、1、2、3、7 h和10 h时取样测定肌肉、肝(胰)脏、血液中MS-222的残留量,10 h后将试验鱼置于清洁水中,分别于0.5、1、2、4、6、8、16、32、96、120、192、264、336、432、528、624、720 h时再测定肌肉、肝(胰)脏、血液中MS-222的残留量。结果显示,MS-222在草鱼、花鲈、鲫鱼的血液、肌肉、肝(胰)脏中残留分别在3、3、7 h达到峰值,随后略下降;MS-222在草鱼血液、肌肉、肝胰脏组织中的消除半衰期分别为5.4、6.7、7.9 h;在花鲈血液、肌肉、肝脏组织中的消除半衰期分别为3.9、5.1、5.7 h;在鲫鱼血液、肌肉、肝胰脏组织中的消除半衰期分别为 4.8 、6.3、8.4 h。MS-222在3种鱼类肝(胰)脏、肌肉、血液中的消除速率均为 V肝(胰)脏相似文献   

15.
Salt (NaCl) and gypsum (CaSO4) are used as water additives to mitigate fish stress and improve specimen survival. High stocking densities and the transportation of fish can increase aqueous ammonia, which can, in turn, alter fish cortisol secretion. The objectives of this study were to assess the effects of salt, gypsum, and aqueous ammonia on some stress‐induced physiological responses of jundiá, Rhamdia quelen, juveniles induced by captivity and handling, and to determine the lethal ammonia concentration for this species. Jundiá juveniles were subjected to the following five treatments: water only, water + ammonia (0.4 mg/L), water + NH3 + NaCl (6 g/L), water + NH3 + gypsum (150 mg/L), and water + NH3 + NaCl + gypsum. Blood samples were taken after intervals of 1, 5, 24, and 96 h, and the concentrations of cortisol, glucose, chloride, ammonia, and hematocrit were determined. The NH3 LC50 value after 96 h of exposure (LC50?96h) was measured to be 1.9 mg/L NH3. Either salt or gypsum reduced both cortisol and glucose levels during most of the experimental period, but the combination of both reduced these levels even further. The combined use of NaCl and CaSO4 demonstrates a synergic effect on mitigating stress responses induced by handling and aqueous ammonia in jundiá juveniles.  相似文献   

16.
Abstract

This study investigated the ability of a simple bacterial denitrification filter (BDF) to reduce nitrate levels in experimental low-intensity recirculating broodstock tanks. These broodstock tanks are equipped with a sand-substrate system which provided the dual purpose of habitat and nitrification filter. The BDF was constructed of 50-mm PVC pipe, filled with 50% gravel and 50% crushed pipi shell. The BDF was designed to be easily fitted to individual tanks (assisting biosecurity) and to operate with minimal management.

There were 3 treatments, each with 3 replicates: control tanks with no BDF; tanks with BDFs receiving 0.605 g C/day as glucose (Low C); and tanks with BDFs receiving 1.512 g C/day as glucose (High C). Kuruma shrimp, Penaeus japonicuswere maintained in all tanks at a density of 185 g/m2 (avg. weight of 8.02±2.4 g), and no water was exchanged for the duration of the experiment. In the control tanks, nitrate increased at about 1 mg/L/day until 38 days when it peaked at 38.9 mg/L. Nitrate levels in control tanks decreased slightly (i.e., by up to 2.5 mg/L) from 38 days to 50 days when the experiment was concluded. In the Low C treatments, nitrate increased at a similar rate at first; however, it peaked at 24 days (18 mg/L) and then gradually reduced to 12 mg/L after 50 days. In the High C treatments, nitrate also peaked at 18 mg/L after 24 days, but then decreased to zero by 50 days.

Sand-substrate in the High C treatment tanks was anoxic by the end of the experiment (black beneath the surface, with redox potential < –100 mV). However, in the control and Low C treatments, where nitrate levels were above 10 mg/L, the substrate remained in good condition (no black sediment, and redox potential –10 to 50 mV).

These results demonstrate that a simply-designed and operated BDF, together with an appropriate nitrification system, can effectively maintain nitrate below 20 mg/L, removing the need for water exchange and improving biosecurity. The BDF operation should be limited to allow nitrate to be maintained at about 10 mg/L, to help maintain oxidized conditions in the sediment.  相似文献   

17.
Exposure to heat‐shock protein (Hsp) stimulating factors induces Hsp accumulation and confers tolerance to lethal ammonia stress on the common carp Cyprinus carpio. This study investigated whether a non‐lethal heat shock bestowed similar protective effects against ammonia and induced thermotolerance, both thought to be rendered by increased amounts of Hsps. The 30‐min lethal temperature (30 min LHT) and 1‐h lethal ammonia concentration (1 h LCT) for this species occurred at 41°C and 14.2 mg/L NH3 respectively. Heating juvenile carp (5 cm) from 28°C to 32, 34 and 38°C, with a subsequent 8‐h recovery period augmented tolerance to lethal heat and ammonia perturbation by two to threefold as compared with animals held at 28°C. Protection occurred in conjunction with Hsp70 accumulation in gills, substantiating the role of this Hsp in enhancing the stress tolerance of common carp.  相似文献   

18.
Two 3-month experiments were conducted to investigate the effects of temperature and water calcium concentrations on growth, survival and moulting of freshwater crayfish (Paranephrops zealandicus). Both experiments were conducted using three replicates of five treatments (water temperatures of 14, 16, 18, 20 and 22 °C for Experiment 1 and water calcium concentrations of 0, 5, 10, 30 and 80 mg/L for Experiment 2). Growth rates increased with water temperature (maximum specific growth rate = 0.57) but were unchanged with increased water calcium concentration. Variability in growth rates decreased with increased water calcium concentrations. Survival decreased as water temperatures exceeded 16 °C and increased with water calcium concentrations above 10 mg/L. Inter-moult period decreased from > 90 ± 20 days at water temperatures of 14 °C to ∼ 40 ± 10 days at water temperatures > 20 °C. Moult increment of the crayfish was unaltered by either water temperature or water calcium concentrations. The optimum water temperature for productivity under conditions employed was 16 °C.  相似文献   

19.
Anesthetics are commonly used in the aquaculture industry to reduce stress and prevent mortality of fish during transportation, handling, and surgical procedures. This study assessed the efficacy of four anesthetic agents (clove oil, propofol, 2‐phenoxyethanol [2‐PE], and ketamine hydrochloride) on Persian sturgeon, Acipenser persicus, juveniles. In addition, results of the first experiment were used to evaluate sedation concentrations suitable for transportation of Persian sturgeon. The concentrations of anesthetics or sedatives evaluated in the first experiment were: 25, 50, 75, and 100 mg/L for clove oil; 1, 1.25, 2.5, and 5 mg/L for propofol; 110, 330, 550, and 770 mg/L for 2‐PE; and 1250, 2500, 3750, and 5000 mg/L for ketamine hydrochloride. Results show significant reduction in time to anesthesia and significant increase in recovery time with increase in concentration of all anesthetics. The most clinically useful concentrations of anesthetics tested were between 25 and 50 mg/L for clove oil, less than 1 mg/L for propofol, 330 mg/L for 2‐PE, and none of the tested concentrations for ketamine hydrochloride. In the second experiment, juveniles were placed in low concentrations of anesthetic solutions for 24 h and survival assessed. The four anesthetics tested are suitable for light sedation during transportation of A. persicus juveniles. Results are helpful to scientists working with Persian sturgeon aquaculture and restocking programs.  相似文献   

20.
The loading density of pirarucu Arapaima gigas transported for 6 hr in open system was assessed on survival, physiological parameters (blood hematocrit, cortisol, lactate and glucose concentrations) and water quality (temperature, pH, ammonia, dissolved oxygen and carbon dioxide). No mortality was observed after fish transportation at 80, 120 and 160 kg/m³, although ammonia and carbon dioxide concentrations increased and dissolved oxygen decreased. Physiological parameters were not affected by loading density but significant differences were observed between sampling periods (immediately before transport, immediately after transport, 24 and 96 hr after transport), except glucose. Hematocrit values increased with time, whereas lactate concentration decreased. No significant differences were observed in blood cortisol levels before and after transport, but concentration increased gradually for 96 hr after transport. According to the results, 9 kg pirarucu may be transported for up to 6 hr at a loading density of 160 kg/m³.  相似文献   

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