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1.
pH值和Ca~(2+)浓度对日本沼虾生长和能量收支的影响   总被引:21,自引:2,他引:19  
本文报道了不同pH值(6.5、7.5和8.5)和不同Ca2+浓度(38.8.61.1和78.8ppm)对日本沼虾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,Ca2+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Ca2+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,其余用于呼吸和排泄。  相似文献   

2.
pH值和Ca2+浓度对日本沼虾生长和能量收支的影响   总被引:19,自引:1,他引:18  
董双林  堵甫山  赖伟 《水产学报》1994,18(2):118-123
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  相似文献   

3.
盐度和饵料对中国对虾碳收支的影响_   总被引:9,自引:1,他引:8  
张硕 《水产学报》1999,23(2):144-149
通过内生长实验的方法测定了中国对虾在不同盐度下摄食日本刺沙蚕及盐度31海水中摄食日本棘少蚕和配合饲料的碳收支。结果显示,盐度5-35范围内,水温25℃时,对虾的碳摄食量在盐度13时达到最大为61.64;而最适生长的盐度条件为20,此时的碳利用效率最高为25.84%,碳的特定生长率最大为3.89%。  相似文献   

4.
鄱阳湖沼虾资源的初步调查   总被引:8,自引:0,他引:8  
鄱阳湖区不同水域的沼虾有8种以上,其中日本沼虾为优势种,可占65%-95%,九江沼虾占1%-10%,贪食沼虾5%-35%,韩氏沼虾为1%-5%,江西沼虾占2%-8%,春沼虾占0.5%-l.0%,粗糙沼虾占0.1%-0.8%,安徽沼虾占1%-2%。日本沼虾在各水体中出现频率为100%,贪食沼虾为8%-55%,九江沼虾则在南湖水域有较为集中分布,出现频率为17%-28%,其它种为0.5%-2%;比较了各采样时间内日本沼虾的平均体长分布和近年捕捞产量的变化,并对其种质资源现状进行了初步分析。  相似文献   

5.
河口低盐区罗氏沼虾养殖试验报告   总被引:2,自引:0,他引:2  
利用对虾养成池,在盐度为5.98~9.0的半咸水中,单养罗氏沼虾,平均亩产108.gkg,平均体长7.78cm;罗氏沼虾与梭鱼混养,亩产罗氏沼虾102.3kg,平均体长8.17cm,亩产梭鱼26.3kg,平均体长18.78cm。与当地养殖中国对虾相比,每亩经济效益高68.3%。专家鉴定认为:本研究技术成果达国内先进水平。  相似文献   

6.
武湖日本沼虾食性的研究   总被引:7,自引:0,他引:7  
在胃含物分析的基础上 ,1998年 9月~ 1999年 9月对人工养殖湖泊武湖日本沼虾的食性作了研究。结果表明 :日本沼虾是一种广食性、杂食性的动物 ,其主要食物是植物碎片和有机碎屑 ,其次为水生昆虫、水生寡毛类、鱼虾和浮游动物 ,浮游植物仅为日本沼虾摄食时所带入 ;日本沼虾的食物组成具有明显的季节性变化 ;大、中、小三种规格的日本沼虾之间存在明显的食性分化 ;摄食强度存在明显的周年变化  相似文献   

7.
盐度对鲤能量收支的影响   总被引:19,自引:0,他引:19  
邱德依 《水产学报》1995,19(1):35-42
以水蚯蚓为饵料,在温度为27℃,盐度为淡水、3、5、7、9的条件下对幼鲤(初始体重为2.19-3.31g)进行了摄食-生长实验,每一盐度下设4个摄食水平(饥饿-饱足),测定了最大摄食率、吸收率、特定生长率、转化效率和能量收支。结果表明:盐度对最大摄食率、特定生长率(SGR)和转化效率有显著影响;盐度对排出废物所占比例(E/C)影响不显著,对代谢能所占比例(R/C)和生长能所占比例(G/C)有显著影  相似文献   

8.
李林春 《水利渔业》2005,25(3):28-29
取样分析了287尾日本沼虾和312尾克氏螯虾,含肉率分别为36.3%(♀)、31.5%(♂)和19.96%,含水率分别为78.84%和76.41%;与其它淡水虾类营养成分比较,其必需氮基酸(EAA)含量分别为35.21%和33.30%,高于罗氏沼虾和南美白对虾,但低于红螯螯虾;南湾水库日本沼虾和克氏螯虾均是高品质蛋白源,但营养价值前者高于后者。  相似文献   

9.
英国斯特林大学水产养殖研究所对罗氏沼虾和日本沼虾两种幼体生长进行比较研究。通过两种沼虾幼体生长比较研究结果表明,发现日本沼虾幼体存活率高于罗氏沼虾幼体存活率20%,其日本沼虾幼体变态速度比罗氏沼虾幼体快。但日本沼虾幼体孵化数大大低于罗氏沼虾,日本沼虾幼体平均孵化数为1500尾,而罗氏沼虾幼体平均孵化数为354100尾。仔虾孵化数的严重差异,直接影响了亲虾需要量。日本沼虾  相似文献   

10.
设日摄食率为0.4%,1.5%,4.0%三种水平,分别测定条纹石Zhi Morone saxatilis幼鱼的代谢及能量的收支情况。处于鲍食及维持状态下,该鱼代谢率增加的峰值分别于摄食后3h及7h内出现,为静止时代谢水平的2.10倍和2.46倍,SDA持续时间均为21h,SDA总耗能量占摄入能的13%和35.8%。条纹石Zhi在饱食时的转化效率K为20.85%。三种摄食水平下条纹石Zhi的能量收支  相似文献   

11.
12.
Previously, we reported 10 PEGE types of 85 tilapia Streptococcus agalactiae(GBS), which shifted from Streptococcus iniae in China, by using PEGE method. Presently, larger and more representative tilapia GBS were isolated, for the ?rst time in China, to characterize their serotypes and genetic diversities more precisely than had done before. 168 GBS strains were distributed in ?ve provinces of China, in which Guangdong, Guangxi and Hainan were the major ones, holding36.9%(62/168), 37.5%(63/168) and 19.6%(33/168), respectively. Serotypes, Ia, Ib and III, were observed in these strains and the most predominant one was Ia(95.2%), which mainly distributed in Guangdong, Guangxi and Hainan. Ia initially occurred in 2009, it shoot up to 32.1% in 2010,but decreased to 16.1% in 2011 before went up to 45.2% in 2012. Ib sporadically occurred during2007–2011, III onlyoccurred in 2012. 14 different PFGE types, including 4 new types(N, O,P and Q), were observed, in which B, D, F and G were the predominant types, holding 83.9%(141/168) of the total GBS strains. Ia corresponded to 11 PFGE types(A–H, N–P), in which type D predominated(51%). Ib represented 3 genotypes(I, J and Q) and III harbored only 2genotypes(N and F). Type N and Fsynchronously presented in Ia and III. In summary, the genetic diversity of tilapia GBS varied by serotypes and changed with geographical locations and years.Although Iastillpredominated, new rareserotypeIII alreadyoccurred in China.  相似文献   

13.
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.  相似文献   

14.
Growth hormone (GH) and reproduction: a review   总被引:5,自引:0,他引:5  
Interaction between growth and reproduction occurs in many vertebrates and is particularly obvious at certain stages of the life cycle in fish. Endocrine interactions between the gonadotropic axis and the somatotropic axis are described, the potential role of GH being emphasised. A comparative analysis of these phenomena in mammals, amphibians and fish, suggests a specific role of GH in the physiology of puberty, gametogenesis and fertility. It also shows the original contribution made by studies on the fish model in this field of investigations.  相似文献   

15.
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.  相似文献   

16.
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.  相似文献   

17.
18.
Two gonadotropins (GtH; Qa and Qb) were purified by gel filtration and ion exchange chromatography from the pituitaries of Indian walking catfish (Clarias batrachus). The presence of GtH during purification was assessed by in vitro oocyte maturation and in vivo steroidogenic activity, and their identities were determined by elution profiles, molecular weight, biological activities and yield. The molecular weights of Qa and Qb were 37 and 42 kDa, respectively, and composed of distinct subunits (Qa: 20 and 14 kDa and Qb: 26 and 18 kDa). Polyclonal antibodies raised against Qa immunostained Qa, Qb and pituitary GtH cells. A competitive Qa‐ELISA was developed whose sensitivity was 6.25 ng mL?1 (1.25 ng well?1) with intra‐ (3.5%) and inter‐ (12.4%) assay coefficients of variation. Displacement curves parallel to the standard were obtained with plasma and pituitary extracts of catfish, Qb and carp GtHII. The assay was validated by measuring the plasma Qa levels after LHRH treatment and in relation to ovarian growth in the female catfish during different reproductive phases. Based on the results, Qa and Qb corresponded to fish LH and FSH respectively. The findings will increase the knowledge of the mechanisms controlling fish reproduction and identification of sensitive phases in fish in captivity for hormonal manipulation.  相似文献   

19.
The endemic, anadromous cyprinidChalcalburnus tarichi is the only fish species known to occur in alkaline Lake Van (Eastern Anatolia, Turkey). EightC. tarichi were maintained individually in Lake Van water (17 – 19°C; pH 9.8; 153 mEq·I–1 total alkalinity; 22 total salinity) and tank water samples analyzed for 24 h in 2 to 4 h intervals. At zero time, < 1µM ammonia was present and urea was undetectable in the tank water; at 24 h, total ammonia and urea made up 114±32 and 35±25µM, respectively. Over the experimental period, ammonia-N and urea-N excretion averaged 1041±494 and 607±169moles·kg–1 fish·h–1, respectively. The extent of urea excretion was highly variable between specimens. Uric acid excretion was not detectable.Urea was present at high concentrations in all tissues and plasma (25 – 35moles·g–1·ml–1) of freshly caughtC. tarichi; total ammonia content of the tissues was by a factor of 1.9 (liver) to 3.0 (brain) lower. High arginase activity (2.4±0.2 U·min–1·g–1) was detected in the liver ofC. tarichi but ornithine carbamoylphosphate transferase, a key enzyme of the ornithine-urea-cycle, was absent. Ureagenesis is likely through degradation of arginine and/or uricolysis. High glutamine synthetase activity (11±0.6 U·min–1·g–1) and low ammonia content in brain suggest that, like other teleosts,C. tarichi has an efficient ammonia detoxification in the brain, but in no other tissue.Nitrogenous waste excretion at alkaline pH is discussed. The ability ofC. tarichi to excrete high levels of ammonia at extremely alkaline pH is unique among teleosts studied so far. The mechanism of ammonia excretion under Lake Van conditions remains to be elucidated.  相似文献   

20.
Tetrahymena is a protozoan parasite, which infects guppy, Poecilia reticulata Peters, and causes substantial economical losses in commercial farms worldwide. Studies of guppy infected by Tetrahymena require standardized infection protocols. The LD50 for Tetrahymena infection of guppies by intraperitoneal (IP) injection was calibrated, and the level obtained was 946 parasites per fish. Guppy infection with Tetrahymena by immersion, imitating the natural route of infection via the integument, was studied under normal or stress conditions. Exposure to cold and netting (CNI) and to cold only (CI) followed by immersion exposure to 10 000 Tetrahymena per mL resulted in 22.5% and 19.2% mortality, respectively, as compared to 14.2% and 10% in groups that were netted only (NI) or non‐stressed (I). Histopathology revealed that immersion infection resulted in a systemic infection. Lysozyme levels, measured 3 weeks after infection, were significantly higher in the CNI group (288 μg per mg protein) compared with CI‐, NI‐ and I‐treated groups (94.5, 64 and 62.3 μg mg?1, respectively). There was no evident parasite immobilization activity in body homogenates, suggesting no development of acquired immunity. Re‐infection by IP injection revealed no increase in protection in any of the treatment groups, mortality range of 56.3–75%, higher than in the non‐exposed control (40.6% mortality).  相似文献   

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