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1.
This study examined the pharmacokinetics and bioavailability of oxolinic acid (OA) in black tiger shrimp Penaeus monodon Fabricius, in brackish water (salinity 10 g L?1) at 28–29°C, after intra‐sinus (10 mg kg?1) and oral (50 mg kg?1) administration and also investigated the net changes of OA residues in the shrimp after cooking (boiling, baking and frying). The haemolymph concentrations of OA after intra‐sinus dosing were best described by a two‐compartment open model. The distribution and elimination half‐lives were 0.84 and 17.7 h respectively. The apparent volume of distribution at a steady state and the total body clearance were estimated to be 2061 mL kg?1 and 90.1 mL kg?1 h?1 respectively. The bioavailability of OA after an oral administration was 7.9%. The peak haemolymph concentration, the time to peak haemolymph concentration and the elimination half‐life after oral administration were 4.20 μg mL?1, 4 h and 19.8 h respectively. Oxolinic acid muscle and shell levels increased to a maximum (muscle 1.76 μg g?1 and shell 8.17 μg g?1) at 4 h post administration and then decreased with the elimination half‐life value of 20.2 and 21.9 h respectively. Residual OA in muscle and shell was reduced by 20–30% by each cooking procedure examined.  相似文献   

2.
Oxytetracycline (OTC) in shrimp shells may be dispersed to the environment as shrimp shred old cuticle in growout ponds. The study aims to assess the kinetics of OTC accumulated in shrimp shell. Sub‐adult male Litopenaeus vannamei in the C–D0 molting stage, were force fed with medicated feeds at various accurate dose levels that included 50, 500 and 1000 mg/kg‐body weight (BW). In addition to hemolymph, hepatopancreas and muscle were serially collected for 50 mg/kg‐BW‐dose group while cuticle was sampled for higher dose levels. All were assayed for OTC by a validated high‐performance liquid chromatography (HPLC) method. Mineral contents in shell samples of 500 mg/kg‐BW‐dose were also determined. The bioavailability markedly decreased with increasing dose due to incomplete dissolution and/or mild dysfunction in absorption. Administered doses, 2.69 and 2.25%, ended up in the shell after dosing with 500 and 1000 mg/kg‐BW, respectively. OTC data after a dose of 50 mg/kg‐BW was fitted into a three‐compartment model with an added shell compartment with r2 of 0.9920. The model was successfully extrapolated to predict OTC distribution in shell at higher doses. In addition, there was evidence that OTC may disturb the biomineralization process via complex formation with calcium and magnesium lowering the exoskeleton mineral contents.  相似文献   

3.
Toxicokinetics has demonstrated abnormal signs in drug distribution/disposition without waiting until the drug damages the tissues/organs. It is a study of the kinetic assessment of administering high‐dose of oxytetracycline (OTC) to white shrimp. Male Penaeus vannamei in the C–D0 molting stage, were force fed with medicated feeds at various accurate dose levels including 500, 1000, and 2500 mg/kg‐body weight (BW). After dosing with different time intervals, hemolymph, muscle, and hepatopancreas were collected, and assayed for OTC by validated high‐performance liquid chromatography method. The simulated profile based on the maximum recommended dose was tested to approach the systemic level where the drug was anticipated not to cause significant toxic responses. OTC kinetic profiles in the hemolymph were fitted into the flow limited model having r2 value between 0.8341 and 0.9373. The relative affinities for the muscle and hepatopancreas changed at dose level exceeding 1000 mg/kg BW. Although hepatopancreatic clearance was non‐linearly related with dose, the persistence of OTC in muscle after 2500 mg/kg BW dosing was observed to indicate abnormalities in drug distribution/disposition. It was hypothesized that the pharmacokinetic alteration after extreme dosing was because of induction of functional abnormalities in hepatopancreas. In addition, a single administration of OTC at 1000 mg/kg BW was anticipated to be a tolerated dose.  相似文献   

4.
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5.
土霉素在锯缘青蟹体内的药物代谢和消除规律   总被引：1，自引：0，他引：1  
采用高效液相色谱法检测土霉素,研究土霉素口灌给药途径下在锯缘青蟹体内的药代动力学。锯缘青蟹口灌给药土霉素50 mg/kg后,其血浆、肌肉和肝胰脏中的药峰浓度分别为16.78±1.98 mg/L、9.39±2.12μg/g和32.12±6.12μg/g,达峰时间分别为4 h、8 h和4 h。血浆中土霉素浓度-时间关系曲线符合一级吸收的二室开放动力学模型。土霉素在锯缘青蟹体内分布广泛,其表观分布容积(Vd)为2.129 L/kg;分布半衰期(t1/2α)和消除半衰期(t1/2β)分别为3.200 h和47.856 h,总体清除率(CLs)为0.063 mL/(kg.h)。肌肉和肝胰脏中土霉素浓度与时间关系的药动学参数采用统计矩原理分析,其消除半衰期(t1/2 z)分别为60.145 h和71.009 h,总体清除率(CLz)分别为0.054 g/(kg.h)和0.037 g/(kg.h)。土霉素在精巢和卵巢中达峰时间分别为8 h和12 h,峰浓度分别为9.83μg/g和10.26μg/g。给药后24 d时,血浆、肌肉、肝胰脏、精巢和卵巢中土霉素含量都已低于0.10μg/g。土霉素在锯缘青蟹体内消除比较缓慢。  相似文献   

6.
The white shrimp, Litopenaeus vannamei, has become a very important species for the development of shrimp aquaculture in Northwest Mexico. However, viral and bacterial diseases are considered a major threat to the development of this industry. In the present study a trial was conducted to evaluate the tissue distribution, maximum concentration, and elimination of the widely used antibiotic oxytetracycline (OTC) in L. vannamei using indoor tanks under laboratory-controlled conditions. OTC was given to shrimp simulating a therapeutic treatment through medicated feed for 14 days followed by a period of feeding without antibiotic for another 14 days to evaluate the elimination pattern. Samples of hemolymph, muscle, and hepatopancreas were taken from medicated animals every two days for 28 days. All tissues were removed and frozen immediately in liquid nitrogen. OTC levels were analyzed by High Performance Liquid Chromatography (HPLC). Results showed an important OTC increase during consumption of medicated feed in all examined tissues. OTC maximum concentrations were 33.54 ± 11.19, 194.37 ± 16.11, and 18.79 ± 5.87 µg g− 1 for muscle, hepatopancreas and hemolymph, respectively. Although the highest OTC level was found in the hepatopancreas, it required only two days after the start of dosing to reach this value, whereas the maximum OTC for muscle and hemolymph was detected after eight days of dosing. Ten days after the cessation of medicated feeding, the drug content in the shrimp tail muscle was under the detectable limit for the method (0.01 µg g− 1 of OTC).  相似文献   

7.
Q Feng  T Gao  H Ji  X Jiang  T Liang  W Gu  G Wu  G Gao  W Wang 《Journal of fish diseases》2010,33(8):639-647
Crab culture is a very important economic industry in China. An epidemic of tremor disease of Chinese mitten crabs, Eriocheir sinensis, has become a serious problem in recent years. A spiroplasm has been proved to be the causative agent of this disease. Oxytetracycline (OTC) is used widely in aquaculture and was confirmed to be very effective against this pathogen. In this study, the distribution and depletion patterns of OTC in crab muscle were evaluated following single intramuscular doses of 2, 8 and 40 mg kg?1 body weight. OTC was detected with a validated HPLC method. Concentration–time profiles were well described by a three‐compartment model with first‐order absorption after a single dose of 8 and 40 mg kg?1. For comparison, a non‐compartment model was employed. A withdrawal time of 48.29 and 55.92 days was suggested prior to consumption after receiving 8 and 40 mg kg?1. A recommended therapeutic dose of OTC in theory was calculated to be 36.37 mg kg?1. OTC was distributed well throughout the body. The elimination of OTC in muscle was slower compared with fish and other crustaceans. A dose of 40 mg kg?1 is suggested for practical use.  相似文献   

8.
This experiment was conducted to study the effects of different forms and levels of manganese (Mn) on the growth performance, antioxidant activities, tissue Mn content and cytosolic manganese superoxide dismutase (cMnSOD) gene expression of Litopenaeus vannamei. Treatments consisted of 0, 10, 20, 30, 40 and 60 mg Mn kg?1 from manganese sulphate (Mn‐S) and manganese methionine (Mn‐Met), providing the actual dietary value of 5.17, 15.62, 25.55, 34.22, 44.48 and 67.90 mg Mn kg?1 Mn‐S, and 5.17, 15.71, 25.36, 35.86, 45.16 and 65.06 mg Mn kg?1 Mn‐Met, respectively. Each diet was fed to triplicate groups of L. vannamei (initial body weight: 1.925 ± 0.002 g) in a recirculated fresh water rearing system for 8 weeks. Weight gain rate (WGR) increased in prawns provided with from 25.55 to 44.48 mg Mn kg?1 Mn‐S and 15.71 to 45.16 mg Mn kg?1 Mn‐Met and then declined above these levels. The lowest protein efficiency ratio (PER) and the highest feed conversion rate (FCR) were observed in prawns fed the control diet (P < 0.05) and showed no significant differences among other treatments (P > 0.05). Survival rate (SR) was not affected by the dietary treatments (P > 0.05). Total SOD and Mn‐SOD activities were higher in the hepatopancreas of prawns fed with Mn‐supplemented diets from 15.71 to 44.48 mg Mn kg?1 (P < 0.05). On the contrary, malondialdehyde (MDA) content was lower in the hepatopancreas of prawns fed the basal diet (P < 0.05). Mn concentrations in the hepatopancreas and muscles increased with increasing levels of dietary Mn supplementation. Moreover, Mn accumulation was lower in the muscle than in the hepatopancreas of the prawns. The mRNA expression of cMnSOD gene in the hepatopancreas of prawns was upregulated with increasing dietary Mn levels of Mn‐S from 25.55 to 44.48 mg Mn kg?1, Mn‐Met from 15.71 to 45.16 mg Mn kg?1 and then plateaued above these levels. Broken‐line regression analysis of WGR indicated that the optimal dietary Mn requirements for juvenile L. vannamei were 32.26 mg Mn kg?1 Mn‐S and 23.90 mg Mn kg?1 Mn‐Met, respectively.  相似文献   

9.
The effect of Streptomyces strains RL8 and N7 on the growth, survival and histological structure of the hepatopancreas of Litopenaeus vannamei was determined. Shrimp post‐larvae of 0.02 ± 0.01 g were fed with diets supplemented with Streptomyces spp. RL8 and N7 at 108 CFU g?1 of feed for 30 days, followed by challenge with Vibrio parahaemolyticus. Toxicity was also assessed by recording the mortality associated with the use of 1‐100 g/L of cell mass and 108‐1010 CFU/g of feed of these strains in Artemia salina and L. vannamei, respectively. The group treated with Streptomyces sp. RL8 had significantly better weight gain (0.62 ± 0.18 g) and survival rates (84.44 ± 5.7%) after challenge, whereas the one fed with Streptomyces sp. N7 showed significantly higher survival rate (57.77 ± 6.8%) than the control group (0.55 ± 0.20 g and 11.11 ± 9.0%, respectively). The hepatopancreas of Streptomyces‐fed shrimps showed better histological integrity with significantly lower degree of atrophy and necrotic tubules than their unfed counterpart. No toxicity associated with these strains was found. Consequently, they can be excellent probiotic candidates to improve the physiological status and prevent infectious diseases of cultured L. vannamei.  相似文献   

10.
Juvenile Litopenaeus vannamei farmed at 3.0 psu were fed five diets containing glucose, sucrose, wheat starch, corn starch or potato starch as the carbohydrate (CBH) source. Shrimp were fed for 50 days to explore the effect of dietary CBH source on growth, body composition and ammonia tolerance. The specific growth rate of body length of shrimp fed glucose was the highest and significantly higher than those fed potato starch. The survival rate of shrimp fed glucose was 89.44%, and it was the highest and significantly higher than those fed wheat starch. Whole shrimp body crude protein and lipid of the corn starch group were 140.2 g kg?1 and 10.1 g kg?1 respectively. And they were significantly higher than those fed wheat starch. Shrimp fed potato starch had higher hepatopancreas and muscle glycogen. Shrimp fed sucrose had higher glucose‐6‐phosphate dehydrogenase and lower pyruvate kinase activities (P < 0.05). Besides, shrimp fed starch produced more B cells in hepatopancreas tubules than those fed glucose or sucrose. Shrimp fed different sources of CBH differed in the number of R cells. After 96‐h of ammonia nitrogen challenge, the survival rate of the treatments from high to low in turn was glucose, wheat starch, corn starch, sucrose and potato starch, and no significant differences were observed among all treatments. Based on shrimp growth and the economic problems of practical production, we recommend wheat starch as CBH source in practical diets for L. vannamei farmed at low salinities.  相似文献   

11.
To confirm the toxicity or the tetrodotoxin (TTX) content of cultured puffer fish in China, 565 specimens of cultured puffer fish (Takifugu rubripes, Takifugu fasciatus or Takifugu obscurus, Takifugu flavidus and Takifugu bimaculatus) were collected from five provinces from November 2007 to November 2008. The toxicity of the skin, muscle, liver and testis/ovary was examined using methods based on a mouse assay for TTX. The results indicated that the skin, muscle, liver and testis of specimens were ‘non‐toxic’ in both of the mouse assays [<10 mouse unit (MU) g?1 or 2.2 μg g?1] from the viewpoint of food hygiene. However, TTX was detected from an ovary sample of the cultured T. rubripes collected from the Shandong province in March 2008, which was 125.43 MU g?1 tissue. The average TTX contents in the muscle, liver and skin of T. rubripes from Hebei and Shandong provinces were the highest in May or July (1.31, 0.90 and 0.62 MU g?1, respectively, in Hebei, and 1.57, 0.32 and 0.16 MU g?1, respectively, in Shandong) and the lowest in January (<0.1 MU g?1 or 0.02 μg g?1). Thus, non‐toxic cultured puffer fish could be produced successfully in mainland China.  相似文献   

12.
The effects of a dietary protease‐complex on growth performance, body composition, digestive and immune enzyme activity of Litopenaeus vannamei and its resistance to a pathogenic Vibrio parahaemolyticus were assessed in a 9‐week trial. A high fish meal diet (HF) containing 200 g kg?1 fish meal and a low fish meal diet (LF) containing 100 g kg?1 fish meal were designed as a positive and negative control respectively. Three other diets (LF+125P, LF+150P, and LF+175P) were manufactured by supplementing graded level of a protease‐complex (125, 150 and 175 mg kg?1, respectively) to the LF diet. All diets were formulated to be iso‐proteic and iso‐energetic. Most performance indices of shrimp fed the LF+175P diets were similar to the HF diet. Among the digestive enzymes, trypsin, lipase and amylase activity in hepatopancreas of shrimp fed LF+175P diets (4576 U mg?1 protein and 16, 32 U g?1 protein, respectively) were higher than those fed the LF diets but lower than the HF diets (P < 0.05). Total superoxide dismutase and polyphenol oxidase contents in both serum and hepatopancreas were higher and serum malondialdehyde content and the cumulative mortality during disease challenge tests were lower for the diets containing the protease‐complex than those fed the LF diets (P < 0.05) with no difference with those fed the HF diets.  相似文献   

13.
Microcystins accumulate in aquatic organisms and can be transferred to higher trophic levels, eventually affecting vector animals and consumers. We examined three levels of an aquatic food chain (Microcystis aeruginosa, Daphnia magna and Macrobrachium rosenbergii) to identify the transfer efficiency and risk of microcystin on prawns. Samples were analysed using ultra performance liquid chromatography‐mass spectrometry (MS)/MS and microcystin‐LR (MC‐LR) distributions in prawn tissues were studied. The results showed that prawns accumulate MC‐LR both directly from M. aeruginosa and indirectly through D. magna which was pre‐exposed to M. aeruginosa. MC‐LR was detected in the gills, digestive tracts and hepatopancreas of the prawns 2 h after exposure. MC‐LR accumulated in prawns to 0.49 ± 0.04 μg g?1 dry weight in hepatopancreas within 24 h, while it was not detected in muscle samples, and rarely appeared in blood samples in such a short period. Although MC‐LR was not detected in muscle, the head including hepatopancreas of the prawns accumulated troublesome amounts of MC‐LR. These results demonstrate that microcystis blooms in prawn farming potentially pose a risk to human consumers, although prawns may be exposed to the bloom for a very short time, hence regular monitoring of blue green algae population is recommended.  相似文献   

14.
Facilitative glucose transporter 1 (GLUT1) is a transporter protein for glucose transport via the plasma membrane of the cells to provide energy through carbohydrate metabolism. GLUT1 cDNA from Litopenaeus vannamei was obtained and analysed in this study. Full‐length GLUT1 cDNA is 2062 bp long and contained a 1506‐bp ORF encoding a 502 amino acid protein, a 270‐bp 5′UTR and a 284‐bp 3′UTR. When shrimp were under acute low salinity stress, the expression in hepatopancreas, muscle, gill and eyestalk was all up‐regulated at 12 h (P < 0.05) and 96 h (P < 0.05), while the expression in the four tissues was all down‐regulated at 6 h (P < 0.05) and 48 h (P < 0.05) . The expression in the muscle of shrimp at water salinity of 3 was lower than that at water salinity of 30 independent of dietary carbohydrate levels, while expression in hepatopancreas, gill and eyestalk was up‐regulated at 200 and 300 g kg?1 carbohydrate levels. The expression in all tissues fed glucose was up‐regulated when compared to the expression in shrimp held at a water salinity of 30. This study suggests that GLUT1 is a conserved protein in L. vannamei, and changes in expression due to environmental salinity and dietary carbohydrate level and source.  相似文献   

15.
β‐1,3‐Glucan with 1.0 g kg?1 was supplemented to a basal diet [control (C)] with different feeding schedules: permanently β‐1,3‐glucan diet (BG) and 14 days BG–14 days control diet (C + BG). Growth and immunological responses [respiratory burst (RB), superoxide dismutase (SOD), catalase (CAT), lysozyme and total protein] in haemolymph, hepatopancreas and muscle of Litopenaeus vannamei were recorded after 84‐day feeding and exposure to nitrite‐N (20 mg L?1) for 120 h. β‐1,3‐Glucan administration did not affect growth performance. However, as compared with control, elevated CAT and lysozyme activities were seen in haemolymph of both BG groups, while significantly higher activities of SOD, lysozyme and RB in hepatopancreas, and higher activities of CAT and lysozyme in muscle were only seen in C + BG group. After nitrite‐N stress, significantly higher haemolymph protein, and hepatopancreas activities of lysozyme and RB were observed in both BG groups, but significantly higher activities of haemolymph SOD was only seen in C + BG group. The mortality in groups BG and C + BG was significantly lower than that in group C, but C + BG group showed a trend of higher nitrite‐N resistance compared with BG group. Considering dietary cost and immunostimulatory effects, the feeding schedule with 14 days BG–14 days control diet is more recommended.  相似文献   

16.
李忠帅  马甡  单洪伟  王腾  肖威 《水产学报》2021,45(11):1825-1834
为探究亚硝态氮胁迫下凡纳滨对虾[体长为(6.8±0.3) cm,体质量为(4.0±0.6) g]体内亚硝态氮的时空分布与能量代谢相关酶活性的响应,实验设置0(对照组)、0.8、4.0和8.0 mmol/L 4个处理组,进行持续96 h的亚硝态氮胁迫实验和12 h的恢复实验。结果显示,凡纳滨对虾死亡率与胁迫浓度呈现显著的正相关性。胁迫6 h内,亚硝态氮在凡纳滨对虾鳃、血淋巴、肠道、肝胰腺和肌肉组织中明显积累,且积累量与胁迫浓度呈现正相关。相同胁迫浓度组,亚硝态氮在对虾鳃中积累最多,肌肉中最少,鳃中的积累量约为肌肉的3倍。Na~+-K~+-ATP酶活性在0.8和4.0 mmol/L组对虾肝胰腺和肌肉中显著升高,而在8.0 mmol/L组的肌肉中显著降低。胁迫各组对虾肝胰腺AMPK活性显著上升,且与胁迫浓度呈现正相关性。恢复期间,除血淋巴(8.0 mmol/L组)外,各组织中亚硝态氮1 h恢复效率均超过50%,且肝胰腺和鳃的恢复效率最高,达到74%以上。血淋巴、鳃、肠道中亚硝态氮恢复到对照组水平的时间最短,均在6 h以内,而水体中亚硝态氮含量显著升高。以上研究表明,胁迫下亚硝态氮会在对虾组织中迅速积累,并引起能量代谢进程的加快;胁迫解除后,积累在体内的亚硝态氮能够迅速排出体外,以减轻毒性影响。本研究结果将为缓解亚硝态氮对养殖对虾毒性效应的研究提供参考。  相似文献   

17.
Oxytetracycline (OTC) is employed in fish farms to contest or prevent bacterial infections. We simulated an OTC treatment at therapeutic level (75 mg kg?1) and at higher doses (150, 300 mg kg?1) for 10 days. A withdrawal period of 10 days was considered for treated carp, carrying out the same chemical and biochemical analyses (total glutathione, superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glutathione S-transferase and malondialdehyde). The aim was to obtain data related to the carryover in muscle and on variations in the antioxidant indicators in liver and kidney. The OTC residual levels in muscle showed a dose–response relationship. After 10 days of treatment at the recommended dose (75 mg kg?1), the mean value in muscle was 295 μg kg?1. After 10 withdrawal days, residues in all treated groups were not entirely eliminated by fish. Residues of recommended 75 mg kg?1 OTC dose were lower than the maximum permitted by EEC regulation: 100 μg kg?1. Disturbance in the antioxidant systems in liver and kidney was recorded in (150, 300 mg kg?1) carp, as well as during the withdrawal period. A lowered superoxide dismutase activity and higher levels of catalase, glutathione peroxidase, glutathione reductase and glutathione were evaluated in liver, while in kidney only higher malondialdehyde and glutathione S-transferase concentrations were recorded for 300 mg kg?1 dose. The therapeutic OTC dose exerted lower effects, and only in liver, enhancement of GPx and GR activities was recorded. After the withdrawal period, altered antioxidant responses in tissues were restored for all three OTC doses.  相似文献   

18.
Wild female catfish Silurus asotus (Linnaeus, 1758) were injected with domperidone (DOM) alone, [d ‐Ala6, Pro9 Net]‐luteinizing hormone‐releasing hormone (LHRH‐A) alone once or twice, LHRH‐A plus DOM once or twice simultaneously at 6‐h intervals, LHRH‐A plus carp pituitary extract (CPE) twice simultaneously at 6‐h intervals and LHRH‐A plus human chorionic gonadotropin (HCG) twice simultaneously 6 h apart respectively. The results indicated that injection of LHRH‐A at a dosage of 0.01–0.02 μg g?1 body weight (BWt) alone induced a low but significant increase in serum gonadotropin (GtH) (P<0.05) and resulted in a very low ovulation rate, while DOM at a dosage of 5 μg g?1 BWt alone did not induce an increase in the serum GtH levels and ovulation; in contrast, LHRH‐A at a dosage of 0.01 μg g?1 BWt plus DOM at a dosage of 5 μg g?1 BWt (termed the Linpe technique) increased the serum GtH (P<0.05) significantly and induced an ovulatory rate of 100%, while LHRH‐A plus CPE or HCG resulted in an increase in the serum GtH (P<0.05) and high ovulatory rate, although the latency period was longer when fish were given LHRH‐A plus HCG or CPE.  相似文献   

19.
An industrial and experimental electrical method for stunning farmed Atlantic cod in air and seawater (SW), respectively, were compared. The impacts of sedation with AQUI‐S? and exercise to exhaustion before electrical stunning were also assessed to monitor the possible depletion of rested muscle energy levels by electrical stunning. Stress (blood glucose, haematocrit, muscle pH, muscle excitability, high‐energy phosphates and rigor mortis) and flesh quality (fillet texture, colour, liquid leakage (LL), gaping, residual blood and K‐value) were assessed. For the industrial stunning method, an average of 41 V, 0.2 A dc was applied to individual cod for 18–27 s. For the SW method, a bipolar square wave current (170 Hz, 33% duty cycle) was applied for 5 s. After stunning, recovery was prevented by exsanguination in chilled SW. There were no differences (P>0.05) between the two stunning methods except for a higher ultimate fillet pH for cod stunned in air 8 days postmortem. Exercise before stunning depleted muscle energy levels at slaughter, increased LL and fillets had redder and darker flesh after storage on ice for 8 days. Electrical stunning (in air) of AQUI‐S?‐treated fish partly depleted muscle energy levels (pH 7.3, ATP 18.7 μmol g?1, PCr 70.1 μmol g?1). However, flesh quality was not affected. Unless pre‐rigor filleting is the chosen processing strategy, electrical stunning of cod seems to be a promising stunning method.  相似文献   

20.
Litopenaeus vannamei (Boone) grown in ponds are exposed to salinities of less than 5 g L?1 during inland shrimp culture or to more than 40 g L?1 from evaporation and reduced water exchange in dry, hot climates. However, dietary requirements for shrimp grown in low or high salinities are not well defined, particularly for fatty acids. Feeding shrimp postlarvae with highly unsaturated fatty acids (HUFA) enhances tolerance to acute exposure to low salinity, as a result of better nutritional status, or/and specific effects of HUFA on membrane function and osmoregulation mechanisms. This study analysed the effect of HUFA supplementation (3% vs. 34%) on L. vannamei juveniles reared for 21 days at low (5 g L?1), medium (30 g L?1) and high salinities (50 g L?1). Juveniles grown at 5 g L?1 had lower survival compared with controls (30 g L?1) or shrimp grown at 50 g L?1, but no significant effect on survival was observed as a result of HUFA enrichment. In contrast, growth was significantly lower for shrimp grown at 50 g L?1, but this effect was compensated by the HUFA‐enriched diet. Osmotic pressure in haemolymph was affected by salinity, but not by HUFA enrichment. Shrimp fed HUFA‐enriched diets had significantly higher levels of eicosapentaenoic acid and docosahexaenoic acid in hepatopancreas and gills. These results demonstrate that growth at high salinities is enhanced with diets containing high HUFA levels, but that HUFA‐enriched diets have no effect on shrimp reared at low salinities.  相似文献   

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