中国对虾（Penaeus orientalis Kishinouye）的几种必需脂肪酸营养价值的比较研究

用四种试验饵料，其中分别含有１％高纯度的ω－３及ω－６不饱和脂肪酸（亚油酸Ｃ１８∶２ω６、亚麻酸Ｃ１８∶３ω３、花生四烯酸Ｃ２０∶４ω６、二十二碳六烯酸Ｃ２２∶６ω，ＤＨＡ）以及一种对照饵料含有５％棕榈酸Ｃ１６∶０和油酸Ｃ１８∶１ω９混合物对中国对虾（ＰｅｎａｅｕｓｏｒｉｅｎｔａｌｉｓＫｉｓｈｉｎｏｕｙｅ）幼虾进行了为期３２天的投喂试验，从成活率、蜕皮次数及增重等实验结果可见二十二碳六烯酸（ＤＨＡ）对中国对虾幼虾具有最高的营养价值。同时，对海捕和人工养殖的中国对虾的脂肪酸组成进行了比较，两者都含有大量的ω－３系列的高度不饱和脂肪酸；但是与海捕虾相比较，人工养殖对虾的ＤＨＡ含量较低，而亚油酸含量较高。上列结果表明在对虾饵料中补充富含ＤＨＡ的脂肪源将有效地促进对虾增产。     

pH和盐度对斑节对虾存活,生长和渗透调节能力的影响

斑节对虾幼虾（平均体重４．２－５．５ｇ）的ｐＨ低临界值使用盐酸醋化海水的静态生物测定的方法来求得。在盐度３２ｐｐｔ进其致死ｐＨ（即９６ｈＬＣ５０的ｐＨ）为３．７（９５％置信度是３．４和４．１）。最小可采用的ｐＨ（此ｐＨ在２３ｄ中使生长减少５％），在盐度为３０ｐｐｔ时估算为５．９。同ｐＨ７．８相比较，长期（２３ｄ）置于低ｐＨ（４．９），盐度为３０ｐｐｔ时，对虾于民分明显减少（Ｐ＜０．００１），而蜕皮     

长毛对虾仔虾对不饱和脂肪酸需求量的初步研究

用正交法对不饱和脂肪酸进行６因素２水平的饲料含量设计，并在对虾营养试验系统中进行饲养实验。结果表明；长毛对虾仔虾的生长率，存活率受不２饱和脂肪酸种类与含量的影响。在本实验条件下，长毛对虾仔虾期Ｃ１６：ｎ，Ｃ１８：ｎ，Ｃ１８；２ｎ，Ｃ１８；３ｎ，Ｃ２０：１－５ｎ和Ｃ２２－２４的最适宜含量分别上饲料的０．２４％，１．４０％，１．８５％，０．４３％，０．７６％和２．２５％。     

微量元素在盐碱地新池塘配方施肥培育鱼种中的效果研究

在施足基肥的盐碱地新池塘中，将有机肥、无机肥氮、磷、微量元素按比例连续不断地配方施肥和水质调控，使水体中ＮＨ４＾＋－Ｎ＋ＮＨ３－Ｎ为０．８３５ ８ｍｇ／Ｌ，ＰＯ４＾３－－Ｐ为０．１２８ ６ｍｇ／Ｌ，ＳｉＯ２为１．４９ｍｇ／Ｌ，Ｎ／Ｐ为６．０２：１。微量元素Ｆｅ、Ｂ、Ｍｎ、Ｚｎ、Ｍｏ、Ｃｏ分别按６０、５０、５０、５、５、５μｇ／Ｌ施入池水，隐藻、硅藻为优势种群的浮游植物总生物量达到４６．９３９ｍｇ／     

之四:虾塘混养泥蚶技术简介

一、虾塘条件要求： １虾塘条件：选择的泥蚶与对虾混养的虾塘首先要排灌方便，具有进排水陡闸，并配备水泵，预防小潮期不能纳潮时使用，虾塘要求其涂面平缓、背风向阳、塘底平整，面积以５—１０亩为宜。 ２．底质要求：以软泥为主，合少量沙质，最好表层软泥厚度为５—１０ｃｍ为佳。 ３水质要求：海水比重３％以上，ｐＨ值为７．８—９．０；水质透明度为３０～５０ｃｍ；氨氮含量０．６ｍｇ／Ｌ以下；底质硫化氢含量０．０１ｍｇ／Ｌ以下；化学耗氧量（ＣＯＤ）６ｍｇ／Ｌ以下。 二、放苗前的准备： １．清淤和翻耕：每年收获后，即着…     

罗氏沼虾人工孵化育苗试验

采用自育自繁亲虾，用温泉水高温，人工育苗１８．５９万尾（０．８－１．０ｃｍ），最高育苗密度１０．３万尾／ｍ＾３，成活率８４．５％；外购亲虾用锅炉提温，人工育苗７．７９万尾（１．６５ｃｍ），育苗密度５．５３万尾／ｍ＾３，成活率６４．９８％，孵化育苗水温２６．０－３０．０℃、ＰＨ７－８．５、盐度１２－１４‰、溶氟４－６．５ｍｇ／ｌ，氨氮０．３－０．８ｍｇ／ｌ。本试验表明，罗氏沼虾人工孵化育苗，在辽宁地     

pH值和Ca2＋浓度对日本沼虾生长和能量收支的影响

本文报道了不同ｐＨ值（６．５、７．５和８．５）和不同Ｃａ＾２＋浓度（３８．８、６１．１和７８．８ｐｐｍ）对日本沼是生长和能量收支的影响，实验结果表明，ｐＨ值对该虾的生长有一定的影响，Ｃａ＾２＋和ｐＨ值在影响其生长的过程中可能有一定的交互作用，ｐＨ值和Ｃａ＾２＋对该虾生长的影响主要是通过影响其能量摄入量实现的，本实验条件下，该虾摄入的能量平均有１５．８％用于生长，１．８％作为粪便排出体外，其余用于呼     

氨氮对三角帆蚌及鱼中毒死亡分析

在水温２８℃，ｐＨ９．５，ＤＯ５．５５０ｍｇ／Ｌ，总氨７４．３６ｍｇ／Ｌ，非离子氨５１．６７ｍｇ／Ｌ的水域，对不同年龄及同一年龄不同规格的三角帆蚌进行了比较。其结果是，不同年龄蚌，幼蚌（一龄蚌）死亡４９．５％，成蚌（三龄蚌）死亡５．１％，老蚌（六龄以上）死亡１１．７％；而同一年龄不同规格的幼蚌６．５－７．７ｃｍ的死亡７４．３％，７．５－９．８ｃｍ的死亡２３．８％。蚌、鱼直接经济损失２１０００多元。     

水质与中国对虾幼虾耗氧量和排泄物的关系

水质与中国对虾幼虾耗氧量和排泄物的关系中国对虾幼虾（０．７６±０．０５ｇ）耗氧量随环境中氨氮（０～１０ｍｇ／Ｌ范围内）的增加而增加，随盐度（１０～３０范围内）和ｐＨ（７．０～８．５范围内）的上升而下降。尿素氮和亚硝酸氮排泄作用随盐度、ｐＨ和环境中氨氮...     

二氧化氯改善养殖水环境效果的研究

使用二氧化氯化处理水养殖用水（实验室规模）测定水化学指标及水中细菌数量的变动，结果表明：（１）二氧化氯能够明显中水环境的溶氧（增氧量为５．８－２２．７％）减低水中ＣＯＤ和ＮＨ３－Ｎ值（ＣＯＤ降低幅度为２６．０－５８．８％，ＮＨ３－Ｎ清除率为１９．４－３８．５％）（２）二氧化氯浓度为０．２×１０＾－３ｍｏｌ／ｍ＾３及１．２×１０＾－３ｍｏｌ／ｍ＾３可有显降低海水中弧菌数及细菌总数，随着药物浓度增大，     

Association between the interannual variation in the oceanic environment and catch rates of bigeye tuna (Thunnus obesus) in the Atlantic Ocean

The environmental processes associated with variability in the catch rates of bigeye tuna in the Atlantic Ocean are largely unexplored. This study used generalized additive models (GAMs) fitted to Taiwanese longline fishery data from 1990 to 2009 and investigated the association between environmental variables and catch rates to identify the processes influencing bigeye tuna distribution in the Atlantic Ocean. The present findings reveal that the year (temporal factor), latitude and longitude (spatial factors), and major regular longline target species of albacore catches are significant for the standardization of bigeye tuna catch rates in the Atlantic Ocean. The standardized catch rates and distribution of bigeye tuna were found to be related to environmental and climatic variation. The model selection processes showed that the selected GAMs explained 70% of the cumulative deviance in the entire Atlantic Ocean. Regarding environmental factors, the depth of the 20 degree isotherm (D20) substantially contributed to the explained deviance; other important factors were sea surface temperature (SST) and sea surface height deviation (SSHD). The potential fishing grounds were observed with SSTs of 22–28°C, a D20 shallower than 150 m and negative SSHDs in the Atlantic Ocean. The higher predicted catch rates were increased in the positive northern tropical Atlantic and negative North Atlantic Oscillation events with a higher SST and shallow D20, suggesting that climatic oscillations affect the population abundance and distribution of bigeye tuna.     

Growth performance,digestive enzyme activity and immune response of Japanese sea bass,Lateolabrax japonicus fed with fructooligosaccharide

In this experiment, a feeding trial was performed to determine the effects of fructooligosaccharide (FOS) on growth performance, digestive enzyme activity and immune response of Japanese sea bass, Lateolabrax japonicus juveniles (initial weight 38.3 ± 0.5 g), and the fish were examined following feeding with six levels of FOS (0, 0.5, 1, 2, 4 and 6 g/kg) for 28 days. Significant enhancement of weight gain (WG) and specific growth rate (SGR) was found in fish fed 1 g/kg FOS incorporated diets (p < .05), while the feed conversion ratio (FCR) in the 1, 2 g/kg FOS groups reduced significantly compared with the control (p < .05). Besides, the crude lipid in the 4, 6 g/kg FOS groups increased significantly compared with the control (p < .05). On the other hand, the erepsin and lipase activities significantly elevated in intestine of fish fed 2 g/kg FOS (p < .05) and the lysozyme activity in serum of fish fed 2 g/kg FOS were significantly higher than that in the control (p < .05). Moreover, the alkaline phosphatase activities in serum of fish fed 0.5, 1, 2 g/kg FOS were significantly higher than in control (p < .05). Regression analysis showed that the relationships between dietary FOS levels and either SGR, FCR, erepsin or lysozyme activities were best expressed by regression equations, and the optimal inclusion levels are 1.37, 1.80, 3.06, 3.11, 1.93 and 1.80 g/kg for SGR, FCR, erepsin, lipase, lysozyme and total superoxide dismutase activities, respectively. Overall, this study revealed that FOS incorporated diets could beneficial for L. japonicus culture in terms of increasing the growth, digestion and immune activities. Under the present experimental condition, the optimal supplementary level of FOS in the diet of L. japonicus is 1–3 g/kg.     

Involvement of gonadal steroids in final oocyte maturation of white perch (Morone americana) and white bass (M. chrysops): in vivo and in vitro studies

Plasma estradiol-17 (E₂), testosterone (T), 17,20-dihydroxy-4-pregnen-3-one (DHP) and 17,20,21-tri-hydroxy-4-pregnen-3-one (20-S) levels were measured by radioimmunoassay (RIA) in white perch (Morone americana) and white bass (M. chrysops) that were induced to undergo final oocyte maturation (FOM) with human chorionic gonadotropin (hCG). Plasma DHP levels increased in females of both species in association with oocyte germinal vesicle migration (GVM) and germinal vesicle breakdown (GVBD) and decreased thereafter. Plasma 20-S levels also increased with oocyte GVM in white bass, but were several-fold lower than DHP levels. Circulating E₂ and T levels were greatest during GVM and GVBD in both species and decreased to low levels during oocyte hydration and ovulation. Follicles from white perch and white bass which received a priming injection of hCG in vivo, produced both DHP and 20-S in vitro after exposure to hCG and their oocytes underwent GVBD. Ovarian incubates from unprimed fish of either species produced only E₂ and T and their oocytes did not complete GVBD. Oocytes from unprimed bass, but not perch, matured when follicles were exposed to hCG in vitro. Both trilostane and cycloheximide blocked in vitro production of DHP and 20-S and oocyte GVBD by white perch follices. DHP and 20-S were equipotent inducers of FOM in the GVBD bioassay. None of several other structurally-related steroids tested were effective within a physiological range of concentrations. These results indicate a role for DHP and 20-S in the control of FOM in white perch and white bass.     

Cardiac,ventilatory and metabolic responses of two ecologically dissimilar species of fish to waterborne cyanide

Changes in heart rate, ventilatory activity and oxygen consumption were determined in trout (Salmo gairdneri) and brown bullhead catfish (Ictalurus nebulosus) during exposure to a steadily increasing concentration of waterborne cyanide selected to produce death in 8–9 hours for each species. The lethal cyanide concentration for the bullheads was an order of magnitude higher than for trout. Trout developed an immediate and gradually increasing bradycardia throughout the exposure period. Cyanide produced tachycardia in the bullhead followed by a gradual onset of bradycardia as the concentration of cyanide was raised. Pericardial injection of atropine (a muscarinic cholinergic antagonist) indicated that bradycardia in the trout was due initially to increased vagal tone but later due to the direct effect of cyanide on the heart. Hyperventilation in the trout persisted throughout the exposure period, although the rate and amplitude fluctuated and was variable between individual fish. During the last hour of exposure (highest cyanide concentration), ventilation was characterized by rapid, shallow breaths followed by a sudden respiratory arrest. The bullheads exhibited hyperventilation during the first 3 hours of exposure followed by a gradual, linear drop in ventilation rate and amplitude until death occurred. Cardiac and ventilatory responses in both species were attributed to stimulation of central and peripheral chemoreceptors by cyanide. Evidence is presented which suggests the initial response in the bullheads was due, at least in part, to gustatory stimulation by the cyanide. Oxygen consumption of the trout remained above pre-exposure levels for the majority of the test period. Oxygen consumption in the bullhead paralleled the changes in heart and ventilatory rates. Whole-body lactate levels of fingerlings of both species during cyanide exposure were measured to estimate the extent of anaerobiosis. Whole-body lactate levels were much greater in the bullheads than the trout, indicating a higher capacity for anaerobiosis, possibly due to a greater fuel supply. Overall, the trout responded to cyanide in a manner similar to that produced by environmental hypoxia whereas the bullheads experienced a gustatory stimulus which masked the hypoxia-like response.     

An overview of stress physiology of fish transport: changes in water quality as a function of transport duration

This study brings an integrated analysis about the relationship between water deterioration and its physiological consequences in live fish transport. The analysis was focused on the transport water and its deterioration, and physiological challenges imposed on the fish. Usual commercial handling procedures employed to mitigate fish stress during transport were discussed. Future topics of research for the establishment of safer fish transport protocols were proposed. Transport was classified into short (≤8 h) or long transport (>8 h). The main issue in short transports should be the prevention of water pH reduction, while in long transports it is the increase in ammonia. Plasma cortisol is the most employed marker for stress and is acutely elevated upon short episodes of transport, but remains elevated even in long‐transport events. Plasma glucose is perhaps a better marker for handling stress. Plasma lactate, pH, osmolality CO₂ and ions should be more often evaluated. Plasma Na⁺ and Cl^‐ are very useful markers of acidosis, due to their respective exchange for H⁺ and , for acid–base regulation. The establishment of species‐specific transport protocols should be preceded by such combined analyses of water and physiological parameters.     

Are hatchery‐reared abalone naïve of predators? Comparing the behaviours of wild and hatchery‐reared northern abalone,Haliotis kamtschatkana (Jonas, 1845)

Abalone populations have declined worldwide, generating interest in enhancement using hatchery‐reared individuals. In many cases, such restoration efforts have met with limited success due to high predator‐induced mortality rates. Furthermore, the mortality rates of outplanted hatchery abalone are often considerably higher than for wild individuals. This study uses northern abalone (Haliotis kamtschatkana) as a case study to determine whether hatchery‐reared abalone behave differently than their wild counterparts. In the field, outplanted hatchery‐reared abalone were significantly less responsive than wild abalone, in terms of number of abalone responding and intensity of response, to nearby movement and to physical contact with an inert probe. Also, when encountering a cue to which all abalone responded (a seastar predator), hatchery‐reared individuals remained subdued. Anti‐predator behavioural deficits in hatchery‐reared abalone were more pronounced in 4‐year‐old individuals than in 1‐year‐old individuals, suggesting an influence of either age or amount of time spent in the hatchery environment. These behavioural differences are expected to increase the vulnerability of hatchery‐reared abalone to predators, and are likely a major cause of their elevated predator‐induced mortality when outplanted.     

Effects of cadmium on the kinetics of calcium uptake in developing tilapia larvae, Oreochromis mossambicus

The toxic effects of Cd²⁺ on Ca²⁺ influx kinetics in developing tilapia (Oreochromis mossambicus) larvae were evaluated. Addition of 20 µg l^-1 of Cd²⁺ to the environment of 0 and 3 day-old larvae competitively inhibited the Ca²⁺ uptake within 4h resulting in a great increase in K_m values for Ca²⁺ influx (19.3 and 17.4 fold, respectively) as compared with their respective controls. Consequently, the actual Ca²⁺ influx of larvae in solutions of 0.2 mM Ca²⁺ are suppressed by 32–45%. Also, 3 day-old larvae were more sensitive to internally accumulated Cd²⁺ than 0 day-old larvae. Although the Ca²⁺ influx in 0 and 3 day-old larvae may be restored to the levels of their respective controls with 24h of being transferred to a 20 µg l^-1 Cd²⁺ solution, total body Ca²⁺ content was significantly reduced in 3 day-old larvae. Increased Ca²⁺ uptake efficiency ensures sufficient Ca²⁺ for normal growth. However, rapid increase in Ca²⁺ influx after hatching also leads to higher Cd²⁺ uptake. Exposure to Cd²⁺ will lead to a drop in body Ca²⁺ content resulting in retardation of larval growth. Therefore, we conclude that if Ca²⁺ uptake is interfered with at this critical stage of development, larvae will not be able to maintain normal levels of body Ca²⁺ and will show signs of Cd²⁺ poisoning.     

Migratory dynamics of stream-spawning longnose gar (Lepisosteus osseus)

Abstract– Literature evidence suggests that lake-dwelling longnose gar (Lepisosteus osseus) enter tributary streams to spawn, Until the present study, the dynamics of this breeding migration had never been investigated quantitatively. During the summers of 1991 and 1992, longnose gar were captured as they entered Weaubleau Creek, Missouri, a tributary of Harry S. Truman Reservoir. The in-stream spawning migration began in early April and ended in late May, and was positively correlated with stream flow and water level, and negatively correlated with water temperature. In-stream residence times ranged from 15 to 94 days, with males exhibiting longer residence times than females. Once in-stream, longnose gar travelled as far as 10 km upstream and occupied certain pools at greater relative frequencies. Although the reason for this preferential utilization is not completely understood, it may relate to pool depth and riffle proximity. Longnose gar disperse from the spawning stream great distances, with gar captured in Weaubleau Creek being recaptured up to 48 km away. This information should provide fisheries biologists the means to consider the reproductive ecology of this species in their conservation and management decisions.     

Nutritional regulation of hepatocyte fatty acid desaturation and polyunsaturated fatty acid composition in zebrafish (Danio rerio) and tilapia (Oreochromis niloticus)

The desaturation and elongation of [1-¹⁴C]18:3n-3 was investigated in hepatocytes of the tropical warm freshwater species, zebrafish (Danio rerio) and Nile tilapia (Oreochromis niloticus). The hepatocyte fatty acid desaturation/elongation pathway was assayed before and after the fish were fed two experimental diets, a control diet containing fish oil (FO) and a diet containing vegetable oil (VO; a blend of olive, linseed and high oleic acid sunflower oils) for 10 weeks. The VO diet was formulated to provide 1% each of 18:2n-6 and 18:3n-3, and so satisfy the possible EFA requirements of zebrafish and tilapia. At the end of the dietary trial, the lipid and fatty acid composition was determined in whole zebrafish, and liver, white muscle and brain of tilapia. Both zebrafish and tilapia expressed a hepatocyte fatty acid desaturation/elongation pattern consistent with them being freshwater and planktonivorous fish. The data also showed that hepatic fatty acid desaturation/elongation was nutritionally regulated with the activities being higher in fish fed the VO diet compared to fish fed the FO diet. In zebrafish, the main effect of the VO diet was increased fatty acid Δ6 desaturase activity resulting in the production of significantly more 18:4n-3 compared to fish fed the FO diet. In tilapia, all activities in the pathway were greater in fish fed the VO diet resulting in increased amounts of all fatty acids in the pathway, but primarily eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3). However, the fatty acid compositional data indicated that despite increased activity, desaturation of 18:3n-3 was insufficient to maintain tissue proportions of EPA and DHA in fish fed the VO diet at the same level as in fish fed the FO diet. Practically, these results indicate that manipulation of tilapia diets in commercial culture in response to the declining global fish oil market would have important consequences for fish fatty acid composition and the health of consumers. Scientifically, zebrafish and tilapia, both the subject of active genome mapping projects, could be useful models for studies of lipid and fatty acid metabolism at a molecular biological and genetic level. This revised version was published online in August 2006 with corrections to the Cover Date.     

Protein and amino acid composition from the mantle of juvenile O ctopus vulgaris exposed to prolonged starvation

Protein and amino acid composition of the mantle of juvenile O ctopus vulgaris (Cuvier, 1797) during fasting for 27 days were determined. Average protein content of octopus mantle was of 711.19 ± 46.80 g kg^?1 DW, and it decreased with increasing fasting days. The non‐essential amino acids content was higher (486.18 ± 11.08 g kg^?1 protein) than essential amino acids (425.82 ± 9.15 g kg^?1 protein) at the start of the experiment (unstarved animals). The results suggest that the amino acid profile of the mantle where the most abundant amino acids are Arg, His, Lys, Gly, Leu and Pro could indicate a prolonged fasting condition (>20 days) or poor nutrition of O . vulgaris. This study supports the idea of using mantle for metabolic needs of starved O . vulgaris suggesting that the degradation pathway of amino acids to pyruvate and tricarboxylic acid cycle intermediates was favoured contrary to the degradation pathway of ketogenic amino acids. Special considerations should be taken concerning Thr, Ile, Ser, Ala, Asx (Asp, Asn), Glx (Glu, Gln) (because of their fast intake) and Lys and His (due to their stable contents) during a prolonged period of fasting.