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1.
对室内工厂化养殖的犬齿牙鲆生长特性进行了研究。结果表明,其生长旺盛期在2龄,日生长最快达5.52g/d,第1年平均为1.65g/d,第2年平均为2.34g/d,第3年平均为1.3g/d,第4年平均为0.75g/d。养殖1周年其平均体重可达600g左右,两周年达1500g;其全长和体重的关系为W=0.0076TL3.1785(R2=0.9765),全长与体高和标准体长的关系分别为TL=2.5685BD-0.6594(R2=0.9823),TL=1.1957SL-0.1724(R2=0.9922)  相似文献   

2.
Abstract

Increasing consumer demand for flounder and dramatic reductions in ocean flounder harvests have raised interest in summer flounder (Paralichthys dentatus) aquaculture. Flounder farmers have several potential markets, including regional seafood dealers and high‐end niche (e.g., sashimi and ike‐jime) buyers. Prices paid by buyers are exogenous to typical aquacultural budgeting models, yet they are a key determinant of potential profitability. We develop a simple economic model to assess the impacts of aquaculture industry supply on prices paid by regional seafood dealers. The model is parameterized for a region with established flounder dealers and active field research in flounder production methods. We derive the price elasticity of regional seafood dealer demand for farmed flounder, and we examine the impacts of changes in production cost and ocean harvest on regional price and the level of aquacultural production that maximizes returns to the aquaculture industry.  相似文献   

3.
The summer flounder, Paralichthys dentatus L., is a high‐value species and considerable research has been conducted to determine practices conducive for its culture. As milt can be limited in this species, experiments were conducted to develop a practical sperm cryopreservation protocol for hatchery use. Two dilution ratios (1:2 and 1:4; sperm:extender), 2 diluents (saline and sucrose‐based), 2 cryoprotectants (10% DMSO and 12% glycerol) and 3 freezing rates (?5, ?10 and ?15°C min?1) were evaluated using differential staining to assess post‐thaw sperm survival. Seven combinations of the factors examined reduced post‐thaw viability by less than 30%. The average viability of sperm from fresh, pooled flounder milt (67.2 ± 2.9%) was not different from that of thawed milt diluted 1:4 with sucrose diluent (10% DMSO) frozen at ?5°C min?1 (38.4 ± 7.7%) and fertilization and hatch success were not different in trials using fresh or thawed, cryopreserved sperm. From these experiments a practical sperm cryopreservation method was developed, but further refinement of the freezing protocol is necessary to optimize results.  相似文献   

4.
用冷冻保存的花鲈精子作为异源精子,采用紫外线(UV)对精子进行照射使其遗传物质失活,然后与卵子进行“授精”,可以刺激犬齿牙鲆鱼卵进行雌核发育,在受精后一定时间采用冷休克处理“授精”卵,抑制第二极体排出成功获得了犬齿牙鲆雌核发育二倍体鱼苗。实验表明:犬齿牙鲆同源精子经80 mJ/cm2 的紫外线照射可以完全失活,冻存花鲈精子经紫外线照射后也同样具有诱导犬齿牙鲆雌核发育的能力。无论同源精子还是异源精子,最佳诱导条件为在18 ℃条件下,精子经80 mJ/cm2的紫外线照射,受精后4~5 min将受精卵放在3 ℃海水中进行冷休克处理,持续时间为45 min,同源精子和异源精子二倍体诱导分别为32.66%±7.03%和28.00%±6.48%。采用形态学、流式细胞仪DNA含量分析和微卫星标记技术对雌核发育鱼苗进行了分析,证明了雌核发育鱼苗为雌核发育二倍体。  相似文献   

5.
In the aquaculture of summer flounder (Paralichthys dentatus), the inherent variation in growth and settling behavior during metamorphosis may lead to cannibalism and necessitate increased labor due to size grading. Our goal was to use an environmental salinity change as a cue to synchronize settling behavior and produce a larger, more uniformly sized cohort of juvenile summer flounder. Early metamorphic flounder were exposed to either a 5-day fluctuating (30–20–30–20–30 ppt; “Flux”) or a single (30–20 ppt; “20 ppt”) drop in rearing salinity. A control (continuous 30 ppt) was used for comparison. Average values for a peak settlement interval (PSI; defined as the interval beginning on the day by which the first 20% had settled until the day 80% had settled) were not affected by salinity manipulation, though the 20-ppt treatment did significantly increase percent settled per day by 54 dah. Average fish size was increased by the 20-ppt treatment (19.3±0.5 mm), but not the flux treatment (17.2±0.4 mm), compared to the control (17.6±0.5 mm). Developmental stage was significantly increased in the 20-ppt treatment (3.2±0.1) in comparison to the Flux (2.9±0.1), but not the control (3.1±0.1). However, the 20-ppt treatment reduced variance in development. To confirm the positive effects of the 20-ppt treatment, a second experiment was performed. A single salinity drop (“20 ppt”), a previously successful ([Gavlik, S., Albino, M., Specker, J.L., 2002. Metamorphosis in summer flounder: Manipulation of thyoid status to synchronize settling behavior, growth, and development. Aquaculture 203 (3-4), 359-373]thyroid hormone manipulation treatment (“TH”) and a combination of the two (“TH+20 ppt”) were compared to a control (continuous 30 ppt, no thyroid manipulation). The mean PSI was significantly reduced by both TH (7±1 days) and TH+20 ppt (8±0 days) treatments, compared to the control (11±1 days). The PSI for the 20-ppt treatment (9±0 days) was not significantly different than the control. The percent flounder settled per day was significantly increased by 20 ppt salinity and significantly modified (decreased, then increased) by TH manipulation. Flounder exposed to 20-ppt salinity were both larger (20 ppt: 18.6±0.3 mm; TH+20 ppt: 18.3±0.3 mm) and more developmentally advanced (20 ppt: 3.1±0.04; TH+20 ppt: 3.2±0.03) than flounder in 30 ppt (TH: 17.8±0.3 mm/3.1±0.3; Control: 17.9±0.3 mm/3.0±0.05). Finally, 20-ppt treatment reduced variance in development, while TH treatment reduced variance in both growth and development. Percent survival was unaffected by treatment in both experiments. In summary, a decrease in rearing salinity, from 30 to 20 ppt, increased growth, settling behavior and development of metamorphosing summer flounder. A decrease in rearing salinity, in combination with a TH manipulation, should result in larger, more uniformly sized flounder cohorts. We expect this synchronization will reduce the cannibalism and labor costs associated with size grading of cultured, metamorphosing summer flounder.  相似文献   

6.
The effects of dietary n-3 highly unsaturated fatty acid (n-3 HUFA) on eggs and larval quality were investigated in the Chilean flounder Paralichthys adspersus . Broodstock were fed with three formulated diets with similar proximate compositions but different n-3 HUFA (2.1%, 3.1% or 4.1%) estimated levels from 5 months before and during the spawning period. The diet with an intermediate n-3 HUFA level resulted in a significantly higher ( P <0.05) percentage of buoyant eggs (68.2 ± 2.9%), fertilization (92.8 ± 3.9%), normal cell cleavages (93.5 ± 1.9%), hatching rate (87.7 ± 4.1%) and normal larvae (76.3 ± 3.7%) compared with the other two diets. In contrast, high levels of n-3 HUFA produced larvae with a higher survival capacity when subjected to fasting. The diet with the lowest content of n-3 HUFA produces lower quality eggs and larvae. The n-3 HUFA level in eggs increased with an increase in the dietary level, and the n-3/n-6 ratios were 1:1, 2:1 and 3:1. The DHA/EPA and EPA/ARA ratios of 2 and 4 in eggs, respectively, were associated with improved egg and larval quality and were similar to the ratios found in eggs from wild broodstock. Attainment of optimal fatty acid contents in broodstock diets is one of the key factors for producing the high-quality spawning required for managed culture of this flounder.  相似文献   

7.
牙鲆(Paralichthys olivaceus)养殖病害日益严重,迟缓爱德华氏菌(Edwardsiella tarda)是牙鲆养殖中的主要致病菌,带来了极大的经济损失,为了培育出对该病抵抗能力强的牙鲆新品种,2014年4–6月间,利用我们长期以来建立和筛选出来的牙鲆抗病群体和家系的亲鱼,通过杂交,自交,雌核发育建立47个家系,9–10月间,对其中39个家系进行感染实验,先用少量鱼进行预实验摸索出半致死浓度,然后再进行正式感染实验,感染数量为每个家系80尾。各家系的存活率范围为1.19%~51.19%,最终平均存活率为20.29%,认为存活率高于30%的7个家系为抗病力强家系,存活率在20.29%~30%的9个家系为抗病力一般家系,平均存活率以下的23个家系为抗病力弱家系。1406#家系抗病力最强,它为1005#家系的自交后代,而其他抗病力强家系也大多是1005#、09104#、0915#的后代。而09104#为0768#的后代,并且0768#抗鳗弧菌病能力强。1005#为韩国群体自交后代,0915#为韩国群体和日本群体杂交后代。这些抗病力强的牙鲆可以作为新品系进行推广养殖,可望减少牙鲆腹水病发生。  相似文献   

8.
A feeding trial with five crude protein levels (549, 513, 472, 445 and 399 g kg?1) was conducted to investigate the optimum protein level in diets of juvenile southern flounder (Paralichthys lethostigma). Budgets of nitrogen and energy were discussed. Fish (initial weight 32.9 ± 0.5 g fish?1, mean ± SD) were fed the experimental diets to satiation twice daily for 61 days. Protein levels affected specific growth rate in wet weight (SGRW) and protein (SGRP) significantly. SGRW and SGRP were highest at 512.5 g kg?1 protein level. SGRW was positively correlated to growth nitrogen (GN), growth energy (GE), nitrogen digestibility, energy digestibility, amount of digestible nitrogen and amount of digestible energy. Faecal nitrogen (FN) and faecal energy (FE) were affected significantly with trends contrary to SGRW. The nitrogen budget was described by the equation 100CN = 2.1FN + 34.4UN + 63.5GN (CN, nitrogen intake; UN, excretion nitrogen). The energy budget was 100IE = 4.04FE +3.32UE + 54.35GE + 38.30ME (IE, gross energy intake; UE, excretion energy; ME, metabolizable energy). The average proportion of GE and ME in assimilated energy (AE) was described by the equation 100AE = 58.65GE + 41.35ME.  相似文献   

9.
将牙鲆基因组DNA经限制性内切酶RsaⅠ和BstUI双酶切后采用FIASCO法构建酶切片段基因组文库。共挑取269个克隆,177个为阳性克隆,阳性克隆率为65.79%。经测序后获得191条微卫星序列,其中完美型占74.35%;非完美型占14.66%;混合型占10.99%。用引物设计软件Primer Premier 5.0设计引物153对,挑选其中的50对合成并在32个野生牙鲆个体中进行扩增,共31个位点具有多态性,统计结果后使用POPGENE软件进行分析,平均等位基因个数为3.939 4,平均有效等位基因数为3.052 2,平均观测杂合度为0.650 1,平均期望杂合度为0.586 6,各引物的Hardy-Weinberg平衡指数在0.012 587~0.984 917变动。这些筛选出的多态性微卫星标记可应用于进一步的牙鲆遗传多样性分析、家系分析及遗传图谱的构建等工作中。  相似文献   

10.
Two monoclonal antibodies (MAbs: JFW1 and JFW10) were produced against peripheral blood leukocytes (PBL) in Japanese flounder. Additionally, MAbs against flounder immunoglobulin (Ig; JFW20 and JFW21) were generated for the surface marker of Ig+ leukocytes using purified serum Ig as an antigen. MAb JFW1 recognized the surface marker of granulocytes and monocytes and MAb JFW10 specifically bound to the surface antigen of thrombocytes. Flow cytometric analysis of PBL incubated with JFW1, JFW10, JFW20 and JFW21 revealed that 2.5–7.4, 23.7–50.1, 25.2–26.1 and 5.2–8.3% of all leukocytes were positive for these markers. Analysis of head kidney leukocytes (HKL) showed that JFW1, JFW10, JFW20 and JFW21 bound to 30.5–36.3, 1.9–2.8, 6.4–8.3 and 1.9–3.0% of all leukocytes, respectively. Western blot analysis after SDS-PAGE showed that JFW10 recognizes a protein of 115 kDa from lysed PBL. JFW20 recognized the 70 and 74 kDa proteins of the heavy chain of Ig from serum. No band was observed for either JFW1 or JFW21. These antibodies will be useful for the identification and isolation of Japanese flounder leukocyte subpopulations and will facilitate immunological studies of flounder.  相似文献   

11.
12.
This study investigated the effect of dietary arachidonic acid (AA) in broodstock of Japanese flounder on subsequent egg and larval quality. Diets with similar proximate composition and n-3 HUFA level, but with different AA levels (0.1%, 0.6% and 1.2% of diet), were fed to the broodstock from 3 months before and during the spawning season. Spawning was observed from March to May. Total egg production over the spawning season was highest in fish fed the 0.6% AA diet and lowest in fish fed the 1.2% AA diet. All parameters measured as egg quality (percentage of buoyant eggs, hatching rate, larval survival and normality of larvae.) were highest in fish fed the 0.6% AA diet. AA content in eggs proportionally increased with the dietary AA level. EPA content of polar lipids of eggs had a negative correlation with the AA level in diets whereas the DHA content was independent of dietary AA. The results of this study indicate that a supplement of AA at 0.6 g/100 g diet improved the reproductive performance of Japanese flounder, but a higher level of AA (1.2 g/100 g diet) negatively affected both egg and larval quality due to a potential inhibitory effect on EPA bioconversion.  相似文献   

13.
The effect of feeding ratio on growth and body composition of juvenile olive flounder fed extruded pellets was determined during the summer season. Thirty juvenile olive flounder (initial body weight of 17 g) per tank were distributed into 21, 180-l flow-through tanks. Seven treatments that included triplicate groups of feeding ratio in 5% decrement were prepared for this study: 100% (satiation), 95%, 90%, 85%, 80%, 75% and 70% of satiation. Fish in the control group were hand-fed to apparent satiation twice a day. Then feed allowance in the rest of the six groups was determined based on average feed consumption in the control group. The feeding trial lasted for 7 weeks. Survival was over 97% and was not significantly (P > 0.05) affected by the feeding ratios. Weight gain and SGR of fish fed to 100% of satiation were not significantly different from those fed to 95% of satiation but significantly (P < 0.05) higher than those of fish fed to 90%, 85%, 80%, 75% and 70% of satiation. Weight gain, SGR and feed consumption of flounder linearly (P < 0.001) decreased with a decrease in feeding ratio. However, feed efficiency ratio, protein efficiency ratio and protein retention in fish body were not significantly (P > 0.05) affected by the feeding ratio. The crude protein levels of the whole body without liver or liver were significantly affected by the feeding ratio. Hepatosomatic index and condition factor of fish were not significantly (P > 0.05) affected by the feeding ratio. It can be concluded that optimum feeding ratio for growth of juvenile olive flounder could be lowered to 95% of satiation without growth suppression.  相似文献   

14.
趋化因子是一类具有化学趋化功能的小分子分泌性蛋白,能够引导白细胞到损伤或者感染的部位,参与免疫调节和病理反应。为丰富鲆鲽鱼类趋化因子的相关基础研究,本研究克隆了牙鲆(Paralichthys olivaceus)趋化因子基因CXCL9,其全长为910 bp,开放阅读框为408 bp,编码135个氨基酸。该基因具有趋化因子超家族的典型特征,在35、37、60和77个氨基酸位置具有4个保守的半胱氨酸残基,形成两个二硫键。氨基酸序列分析表明,该基因与大菱鲆(Scophthalmus maximus)、半滑舌鳎(Cynoglossus semilaevis)的CXCL9基因具有较高的同源性,分别为78.5%和71.0%。实时荧光定量PCR结果显示, CXCL9在正常牙鲆肝脏和脾脏中的表达量非常高,在皮肤和鳃等组织中表达量次之,说明CXCL9特异性地在免疫相关组织中表达。经迟缓爱德华氏菌(Edwardsiella tarda)感染后,牙鲆肝脏中CXCL9 mRNA表达量在感染后6 h即出现高峰值,而头肾和脾脏中的高峰值出现较晚。经鳗弧菌(Vibrio anguillarum)感染后6 h,牙鲆肝脏中CXCL9 mRNA的表达量升高近8倍,头肾中的表达高峰值出现在感染后24 h,而脾脏中CXCL9 mRNA的表达量在感染后6 h迅速升高10倍,逐渐降低后48 h又出现高峰,为正常水平的20倍。上述研究结果说明CXCL9基因在病原菌感染过程中有快速响应,可能参与了免疫防御过程,将有可能发展为一种牙鲆细菌性疾病的生物标记。本研究为牙鲆趋化因子超家族免疫机制的深入研究奠定了基础。  相似文献   

15.
16.
Feeding experiments and laboratory analyses were conducted to establish the essential fatty acid (EFA) requirement of red drum (Sciaenops ocellatus). Juvenile red drum were maintained in aquaria containing brackish water (5 ± 2‰ total dissolved solids) for two 6-week experiments. Semipurified diets contained a total of 70% lipid consisting of different combinations of tristearin [predominantly 18:0] and the following fatty acid ethyl esters: oleate, linoleate, linolenate, and a mixture of highly unsaturated fatty acids (HUFA) containing approximately 60% eicosapentaenoate plus docosahexaenoate. EFA-deficient diets (containing only tristearin or oleate) rapidly reduced fish growth and feed efficiency, and increased mortality. Fin erosion and a “shock syndrome” also occurred in association with EFA deficiency. Of the diets containing fatty acid ethyl esters, those with 0.5–1% (n-3) HUFA (0.3–0.6% eicosapentaenoate plus docosahexaenoate) promoted the best growth, survival, and feed efficiency; however, the control diet containing 7% menhaden fish oil provided the best performance. Excess (n-3) HUFA suppressed fish weight gain; suppression became evident at 1.5% (n-3) HUFA, and was pronounced at 2.5%. Fatty acid compositions of whole-body, muscle and liver tissues from red drum fed the various diets generally reflected dietary fatty acids, but modifications of these patterns also were evident. Levels of saturated fatty acids appeared to be regulated independent of diet. In fish fed EFA-deficient diets (containing only tristearin or oleate), monoenes increased and (n-3) HUFA were preferentially conserved in polar lipid fractions. Eicosatrienoic acid [20:3(n-9)] was not elevated in EFA-deficient red drum, apparently due to their limited ability to transform fatty acids. Red drum exhibited some limited ability to elongate and desaturate linoleic acid [18:2(n-6)] and linolenic acid [18:3(n-3)]; however, metabolism of 18:3(n-3) did not generally result in increased tissue levels of (n-3) HUFA. Based on these responses, the red drum required approximately 0.5% (n-3) HUFA in the diet (approximately 7% of dietary lipid) for proper growth and health.  相似文献   

17.
Tomita  Yuki  Ando  Yasuhiro 《Fisheries Science》2009,75(2):445-451
Positional distribution of fatty acids in triacyl-sn-glycerols (TAG) of the flathead flounder Hippoglossoides dubius has been reinvestigated in order to accurately determine the contents of tetracosahexaenoic acid (24:6n-3) in the sn-1, sn-2, and sn-3 positions. Flesh TAG obtained from three flounders were subjected to stereospecific analysis using a suitable procedure for fish TAG analysis. The 24:6n-3 acid was found in the three positions at the concentrations of 0.3–5.5 mole% (the sn-1 position), 1.6–23.3 mole% (the sn-2 position), and 0.6–8.9 mole% (the sn-3 position). In contrast to a previous analysis, the present analysis revealed that 24:6n-3 is preferentially esterified in the sn-2 position followed by the sn-3 and sn-1 positions. Other polyunsaturated fatty acids, docosahexaenoic acid (22:6n-3; DHA) and docosapentaenoic acid (22:5n-3; DPA), showed a similar distribution pattern. These results indicate that the general tendency observed for long-chain polyunsaturated fatty acids in marine fish TAG can be extended to the distribution of 24:6n-3 in flathead flounder TAG. Because the use of flathead flounders is entirely for human food, we thus intake 24:6n-3 concentrated in the sn-2 position of their TAG.  相似文献   

18.
花鲈冷冻精子诱导漠斑牙鲆雌核发育   总被引:3,自引:0,他引:3  
采用紫外线(UV)对冻存的花鲈精子进行照射使其遗传物质失活,作为异源精子诱导源,与漠斑牙鲆卵子进行“授精”,可以诱导漠斑牙鲆卵进行雌核发育。结合静水压处理,抑制第二极体排出,成功获得了漠斑牙鲆雌核发育二倍体鱼苗。实验表明,同源精子和异源精子均可在紫外线照射遗传失活后诱导漠斑牙鲆卵雌核发育,经实验筛选出异源精子诱导漠斑牙鲆雌核发育的最佳条件为花鲈冻存精子采用80 mJ/cm2的紫外线照射,然后与漠斑牙鲆卵子进行授精,培育水温18 ℃条件下,受精后4~5 min,施以65 MPa的静水压休克处理6 min,可有效诱导漠斑牙鲆卵的雌核发育。采用形态学、流式细胞仪DNA含量分析和微卫星标记技术对雌核发育鱼苗进行了分析,证明了雌核发育鱼苗为雌核发育二倍体。本文首次报道了采用异源冷冻精子诱导漠斑牙鲆鱼卵进行雌核发育的技术方法,为漠斑牙鲆性别控制和遗传改良提供了技术手段。  相似文献   

19.
以18日龄的牙鲆(Paralichthys olivaceus)稚鱼为研究对象,通过11 d 的生长实验,研究了添加不同比例的微藻粉替代鱼油对牙鲆稚鱼生长、存活率和脂肪酸组成的影响。以鱼油组(FO)为对照组,以裂壶藻粉(Schizochytrium sp.)、微绿球藻粉(Nannochloropsis sp.)和橄榄油替代不同比例的鱼油,配制成5组等氮等能的实验饲料,分别命名为鱼油组(FO),50%混合替代组(M50)、100%混合替代组(M100)、100%裂壶藻橄榄油替代组(S100)、100%微绿球藻橄榄油替代组(N100)。结果显示,微藻粉替代鱼油对牙鲆稚鱼的生长无显著影响;含有裂壶藻的各饲料组(M50、M100、S100)成活率显著高于 FO 组和 N100组(P?0.05);微藻粉替代鱼油不影响牙鲆稚鱼主要脂肪酸的组成;Person相关性分析发现,C14:0、C16:1n-7、C18:2n-6、C20:0、C18:3n-3、C22:0、C20:4n-3、EPA、C22:5n-6和 DHA 的百分含量均与其饲料中的百分含量呈显著正相关(P<0.05);总饱和脂肪酸、总单不饱和脂肪酸、n-3多不饱和脂肪酸的百分含量以及 DHA/EPA 比率均与其饲料组成表现出显著正相关(P<0.05)。综上所述,微藻作为脂肪源替代鱼油完全可以满足牙鲆稚鱼的生长和发育,各种脂肪酸均可以被牙鲆稚鱼充分消化和吸收,并且添加两种微藻后提高了稚鱼的 DHA 含量和 DHA/EPA 比率,与鱼油对照组相比显著提高了牙鲆稚鱼的成活率。因此,以微藻替代鱼油在牙鲆稚鱼的培育中是可行的。  相似文献   

20.
Muscle proximate composition, amino acid profiles, fatty acid compositions and selected minerals of wild, pond and factory cultured Japanese flounder adults were compared in this study to elucidate their nutritive values and dietary nutrition requirements. Wild and pond cultured Japanese flounder flesh had higher crude proteins, but crude lipid contents of factory cultured fish were 3.8~4.0 fold greater. Major amino acids in Japanese flounder were aspartic acid, glutamic acid and lysine. Wild fish had higher levels of total amino acids, essential amino acids, nonessential amino acids and half‐essential amino acids and the contents in pond cultured samples were similar. Arachidonic acids (ARA), eicosapentaenoic acids (EPA), docosahexaenoic acids (DHA), polyunsaturated fatty acids (PUFA), DHA + EPA and n–3 PUFA in wild Japanese flounder were significantly higher than that in factory cultured fish, whereas fatty acid levels were close between pond cultured and wild fish. Japanese flounder were rich in zinc, iron and selenium, but poor in copper, chromium and nickel. Results indicated wild Japanese flounder had higher nutritional value and better meat quality, but the nutritional compositions of pond cultured fish were close to wild Japanese flounder, which suggested that pond culture of Japanese flounder offers broad application prospects.  相似文献   

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