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1.
ＩＮＴＲＯＤＵＣＴＩＯＮＬｉｍｎｏｄｒｉｌｕｓｈｏｆｆｍｅｉｓｔｅｒｉ,ａｕｂｉｑｕｉｔｏｕｓｔｕｂｉｆｉｃｉｄ ,ｉｓａｐｒｅｄｏｍｉｎａｎｔｂｅｎｔｈｉｃｉｎｖｅｒｔｅｂｒａｔｅｉｎｍｏｓｔｓｈａｌｌｏｗｅｕｔｒｏｐｈｉｃｌａｋｅｓｉｎＣｈｉｎａ (Ｌｉａｎｇ,1 979) .Ｓｏｆａｒ,ｔｈｅｒｅａｒｅｎｏｄａｔａｏｎｔｈｅｓｅｃｏｎｄａｒｙｐｒｏｄｕｃ ｔｉｏｎｏｆｔｈｉｓｗｏｒｍａｎｄｆｅｗｄａｔａｏｎｔｈａｔｏｆｏｔｈｅｒｚｏｏｂｅｎｔｈｏｓｒｅｐｏｒｔｅｄｉｎＣｈｉｎａ .Ｗｉｔｈｔｈｅｆｉｓｈｅｒ…  相似文献   

2.
An 8 weeks feeding experiment was conducted to determine the effect of dietary potassium on the growth and physiological acclimation of Pacific white shrimp(Litopenaeus vannamei) reared in diluted seawater(salinity 4). Six semi-purified practical diets containing 0.59, 0.96, 1.26, 1.48, 1.74, and 2.17+ g potassium K per 100 g diet were formulated, respectively. The survival and feed conversion rate did not show significant difference among groups of shrimps given these diets(P0.05). The shrimps fed the diets containing 0.96-1.48 g K+ per 100 g diet gained the highest weight, specific growth rate, and protein efficiency ratio. Their ammonium-N excretion rate as well as hemolymph concentration of Na+ and Cl- were significantly lower than those of the control(P0.05), but a reverse trend was observed for their gill Na+/K+-ATPase. Moreover, the shrimps fed with 1.48 g K+ per 100 g diet were the highest in hemolymph urea level, and the phenoloxidase and lysozyme activities were significantly higher than those of the control(P0.05). The growth and physiological response of the test shrimps suggested that diet containing 1.48 g K+ per 100 g diet improved the growth of L. vannamei in low-salinity seawater, and enhanced the physiological acclimation of the organism.  相似文献   

3.
以鱼粉和酪蛋白为蛋白源,添加鱼油、豆油、α-马铃薯淀粉、纤维素以及适量的维生素和矿物质配制成实验饲料,蛋白质质量分数设置41%、47%、53%3个水平,能量设置12 561、14 655、16 748 kJ/kg 3个水平,饲养点带石斑鱼幼鱼59 d后,以增重率、蛋白质效率、饲料系数为评价指标,分析不同能量蛋白比的饲料对点带石斑鱼体内消化酶活性的影响。结果表明:当能量蛋白比分别为31.30、33.50、32.26 kJ/g时,点带石斑鱼增重率、蛋白质效率达到极大值,饲料系数达到极小值;能量蛋白比在31.62～35.54 kJ/g范围内,胃、肠道的蛋白酶、淀粉酶、脂肪酶活性较强。点带石斑鱼幼鱼配合饲料中合适的能量蛋白比为31.62～33.50 kJ/g。  相似文献   

4.
For the first time,the present study reports the life-history traits,comprising length-frequency distribution(LFD),sex ratio(SR),length-weight relationships(LWRs),condition factors(CFs),and relative growth(W_R),of Clupisoma garua in the coastal waters of Bangladesh.A total of 150 specimens ranging from 8.60 to 25.20 cm total length(TL)and 4.26 to 128.80 g body weight(BW)were collected using traditional fishing gear from August 2013 to July 2014.The overall sex ratio of males to females in the study did not dif fer significantly from the expected value of 1:1(χ~2=0.96,P0.05)but there were significant sex differences(P0.05)in the intercepts and slopes of graphs characterizing traits in C.garua.The calculated bvalues for the LWRs were 2.955,2.893 and 2.927 for males,females and combined sexes,respectively,and there was negative allometric growth in all cases(b3).The condition factors(K_A,K_F,K_R)and relative growth(W R)also did not differ significantly(P0.05)between the sexes.This study provides a useful tool for fi shery specialists to evaluate the relative condition of fish and to initiate early management strategies and regulations for the sustainable management of the remaining stocks of this species in the entire coastal region of southern Bangladesh.  相似文献   

5.
April, 1996 to March, 1997 studies on the abundance and secondary production of Limnodrilus hoffmeisteri in an algae-dominated lake showed that the worm density and biomass peaked in December at 152 ind/m^2 and 0.087 g/m^2 , respectively. The secondary production of the animal was 0.294g/m^2 fresh wt/a. The turnover rate (P/B ratio) was 11.4.  相似文献   

6.
The present study was conducted to evaluate the feasibility of replacing fish meal (FM) with bioactive peptides (BPs) in diet of white shrimp (Litopenaeus vannamei). The changes in growth performance, body composition, non-specific immunity, and water quality were examined after the shrimp were fed four diets, in which 0% (control), 33.3%, 66.7% and 100% of FM was replaced by BPs, respectively. The groups were designated as Con, 1/3BPs, 2/3BPs, and 3/3BPs. A total of 720 shrimp with an initial body weight of 1.46 ± 0.78 g were fed the experimental diets for 56 days. The results revealed that: 1) the weight gain rate (WGR) in 1/3BPs, 2/3BPs, and 3/3BPs was significantly higher than that in Con (P < 0.05), while no significant difference was found on survival rate and feed conversion ratio (FCR); 2) the whole-body crude protein (CP) and crude lipids (CL) were significantly different among groups, while there was no significant difference between crude ash and phosphorus contents; 3) the levels of acid phosphatase (ACP), lysozyme (LZM), superoxide dismutase (SOD), phenol oxidase (PO) and bactericidal activity increased significantly with the inclusion of BPs; 4) in terms of water quality, no significant difference was found in pH and dissolved oxygen among diets during the whole experimental period. Moreover, even though nitrite and ammonium levels tended to increase with time, there was no significant difference among groups. The results indicated that BPs is an applicable alternative of protein source, which can substitute FM in the diets of L. vannamei; it is able to effectively promote growth performance and improve immunity. Moreover, BPs in the diets had no negative impact on water quality.  相似文献   

7.
复方中草药对吉富罗非鱼生长及肠道菌群的影响   总被引：1，自引：0，他引：1  
将A、B、C三种复方中草药分别按质量分数1.5%的比例添加到罗非鱼商品饲料中,喂养初始体重约16.58±0.48g的吉富罗非罗28d,通过测定罗非鱼的增重率、饲料系数、肠道菌群等指标,研究三种复方中草药制剂对罗非鱼生长性能及肠道菌群的影响。结果显示:三种复方中草药制剂对罗非鱼的增重率、成活率、饲料系数等生长性能指标虽无显著影响(P>0.05),但与对照组相比,添加1.5%的复方中草药制剂C可使吉富罗非鱼的增重率提高10.82%,饲料系数降低4.71%,蛋白质效率提高15.68%;三种复方中草药制剂均可显著促进罗非鱼肠道细菌、双歧杆菌、乳酸杆菌的生长(P<0.05),C方中草药制剂还可显著抑制大肠杆菌生长(P<0.05)。结果表明,C方中草药制剂可显著促进罗非鱼肠道中乳酸杆菌等有益菌群的增殖,抑制大肠杆菌生长,从而有效促进罗非鱼生长。  相似文献   

8.
以煤油为溶剂,TBP为萃取剂,研究了CTAB对于Cr(VI)萃取率的影响。结果表明,CTAB能够有效改善Cr(VI)迁移效果,且在一定条件下,可使Cr(VI)萃取率提高到98%,应用于实际电镀废液,回收率在90%以上。  相似文献   

9.
企鹅珍珠贝人工养殖及育珠的研究   总被引：1，自引：0，他引：1  
在幼贝中间养成中采用柱形笼养殖法,母贝的养成中采用穿耳开放式养殖法,与全程采用锥形笼的传统式养殖方法相比较,进行企鹅珍珠贝人工养殖。结果表明:采用本技术养殖企鹅珍珠贝,在幼贝中间养成阶段,比传统养殖的壳高生长速率提高32·1%(P<0·05),壳长生长速率提高30·3%(P<0·01),成活率提高36%(P<0·01);母贝养成阶段,比传统养殖的壳高生长速率提高28·1%(P<0·05),壳长生长速率提高26·7%(P<0·01),成活率提高18·3%(P<0·01)。同时进行企鹅珍珠贝人工培育游离珠实验,植核贝在休养期和育珠期存活率分别为71·2%和54·3%,留核率分别为29·6·6%和21·0%,成珠率58·6%,优质珠比例为26·7%。  相似文献   

10.
This study was conducted to evaluate the effects of plant/animal(P/A) protein ratios(viz.1:4, 1:3, 1:2, 1:1,2:1, 3:1, 4:1) on growth performance, body composition, apparent digestibility of diets, and nonspecific immunity of juvenile sea cucumber(Apostichopus japonicus). Sea cucumbers were divided into 21 plastic tanks, and each tank was stocked with 15 individuals(initial weight: about 23.73 g). Each feed was allocated to three replicates of sea cucumbers. The feeding experiment lasted for 50 days. Results indicated that weight gain rate(WGR) and body wall weight(BWW) significantly increased as dietary ratio of P/A increased from 1:4 to 3:1, and then decreased significantly with further increase of this ratio(P 0.05). The body wall coefficient(BWC) showed a similar tendency to WGR and BWW, but no significance was detected among dietary treatments(P 0.05). The apparent digestibility of dry matter, protein and lipid increased with ratio of P/A increasing from 1:4 to 2:1(P 0.05), and then decreased with further increase of this ratio. Correspondingly, activities of trypsin and amylase were significantly increased as P/A increased from 1:4 to 2:1(P 0.05). The activities of SOD and CAT showed a similar trend with WGR, with the highest value observed in the ratio of 1:2 and 1:1, respectively. Results above showed that moderate or relatively higher ratio of P/A protein(1:1-3:1) significantly increased the growth performance, apparent digestibility, and nonspecific immunity of sea cucumber. This will contribute to improving the feed formulation for juvenile cucumbers.  相似文献   

11.
研究0、300、600、900、1 200、1 500 mg/kg 6个L-肉碱添加水平对牙鲆(Paralichthys olivaceus)幼鱼生长、生化组成和血液指标的影响。结果表明:添加量为1 200 mg/kg的处理组牙鲆幼鱼的增重率和特定生长率显著提高,饲料系数显著降低(P<0.05);随着饲料中L-肉碱含量的增加,肝指数呈现下降趋势,且在添加量为900~1 500 mg/kg时,各组较对照组差异显著(P<0.05);饲料中添加L-肉碱显著降低各实验组脏体比(P<0.05),而对各处理组间存活率和肥满度均无影响(P<0.05);肌肉和肝脏中的脂肪含量与L-肉碱添加量呈负相关,当添加量为1 200~1 500 mg/kg时,较对照组差异显著(P<0.05);肌肉中的蛋白含量与L-肉碱添加量呈正相关,但各组差异不显著(P<0.05);饲料中添加L-肉碱降低血清中的谷草转氨酶、胆固醇、甘油三酯和尿素氮含量,且添加量1 200 mg/kg组各指标含量均显著低于对照组(P<0.05);各处理组的血糖含量较对照组均有所增加,其中1 200 mg/kg组血糖含量较对照组提高41.6%(P<0.05);血清中总蛋白和低密度脂蛋白均随着L-肉碱添加量的增加而呈下降趋势,高密度脂蛋白却得以提升,但差异均不显著(P<0.05)。分析认为,在本实验条件下,饲料中添加L-肉碱可促进牙鲆幼鱼生长,且降脂效果显著。建议L-肉碱最适添加量为1 200 mg/kg。  相似文献   

12.
A full life-cycle toxicity test,combined with histology,on calanoid copepod Schmackeria poplesia was used to study the effect of bis(tributyltin)oxide(TBTO).The results indicate no sex-specific differences in TBTO toxicity.Long-term mortalities of the copepods exposed to concentrations higher than 20 ng TBTO L-1were significantly elevated compared with that of control,and larval development was inhibited when they were exposed to 40 and 60 ng TBTO L-1.The percentages of ovigerous females were reduced compared with the control(P0.01)after 24 days exposure to concentrations higher than 10 ng TBTO L-1.Histological examinations suggest that exposure to TBTO might block the posterior end of the diverticula and inhibits the production of egg sacs.A modified Euler-Lotka equation was used to calculate a population-level endpoint,the intrinsic rate of natural increase(rm),from individual life-table endpoints,i.e.mortality rate,time of release of first brood,sex ratio,the fraction of ovigerous females among all females as well as the number of nauplii per ovigerous female.Apart from the highest TBTO concentration(60 ng L-1),where all females aborted their egg sacs,20 ng TBTO L-1was the only concentration that significantly decreased rm compared with that of control(an effect associated with decreased sex ratio).The results show that the S.poplesia is affected by prolonged exposure to low concentrations of TBTO.The full life-cycle toxicity test combined with histology experiments provides more integral understanding of the toxicity of endocrine disrupters.  相似文献   

13.
The use of LIDAR-derived shaded relief maps led to the identification of all potential landslide areas in a hilly region in Northern Bavaria (1590 km2), Germany. Every possible structure was investigated by field investigation which resulted in a detailed database of 1002 landslides within the study area. The analysis of geological, lithological, topographical and morphological properties (spatial ratio, lithological and geological setting, length/width distribution, material properties and slope angle) revealed characteristic appearances of the landslides and possible relationships between different aspects. Strong relations between the lithological setting, spatial ratio of the mapped landslides and distribution of slope angle could be observed. This study shows the value of high-resolution shaded relief maps for detecting and mapping landslides in a large area with comparatively little work and time in comparison to the traditional approach to mapping. It reveals that many landslides were not known before. Landslides are much more common in Northern Bavaria and have a higher influence on the denudation rate of the Franconian Alb than expected before.  相似文献   

14.
描记采于云南省邱北县一地下洞穴盲金线鲃一新种,以其头上骨质突形状如鹰喙命名鹰喙角金线鲃Sinocyclocheilus aquihornes sp.nov.。新种头形及完全退化的眼与分布于云南泸西阿庐古洞的透明金线鲃S.hyalinus Chen et Yang(1994)相近,但有下列特征可区别:1)角形如鹰喙,后者为一向前的直突起;2)侧线完全,侧线鳞为36,后者侧线不完全,侧线鳞孔9-11;3)背鳍起点位于体中点,至吻端的距离等于至尾鳍基的距离;后者背鳍起点位于体中点之后,至吻端的距离大于至尾鳍基的距离。  相似文献   

15.
The gonads of sea urchins(Strongylocentrotus intermedius) are characterized by high levels of arachidonic acid(ARA, 20:4 n-6) and eicosapentaenoic acid(EPA, 20:5 n-3). However, to our knowledge, little information is available regarding the physiological response of adult sea urchins to dietary ARA. In the present study, four dietary feeds were formulated with graded ARA(0, 0.5%, 1%, and 2% dry diet). Each diet was randomly allocated to three cages during a 56-day feeding experiment. The results showed that the sea urchin weight gain rate(WGR) and the gonadosomatic index(GI) significantly increased as ARA was equal to or above 1.0% of dry diet(P 0.05). The activities of superoxide dismutase(SOD), catalase(CAT), and total anti-oxidative capacity(T-AOC) were the highest in the coelomic fluid of sea urchins that were fed diets with 1% ARA. The total essential amino acid(TEAA) and its ratio to total non-essential amino acid(TNEAA) showed a similar tendency to WGR and GI as dietary ARA increased, and the highest TEAA and TEAA/TNEAA were observed in the gonads of sea urchins that were fed diets with 1% ARA. Levels of ARA and ARA/EPA of the gonads increased while n-3/n-6 polyunsaturated fatty acid(PUFA) decreased with the increase of dietary ARA(P 0.05). EPA in the gonads of experimental animals fed with formulated feeds showed no significant differences(P 0.05), but was significantly lower than those fed with kelp(P 0.05). These results suggested that relatively higher levels of ARA(1% dry diet) significantly promoted growth, gonad development, activities of antioxidant enzymes, as well as nutritional values(TEAA, TEAA/TNEAA, and PUFA) of adult S. intermedius.  相似文献   

16.
The aim of this study was to investigate the effects of light intensity and enhanced nitrogen supply on the growth and photosynthesis of the green-tide macroalga, Ulva prolifera. Thalli of U. prolifera were grown in natural or NH 4 +-enriched seawater under two different light intensities for 7 days, and then the growth rate, pigmentation, and photosynthetic performance of the thalli were evaluated. The results show that the relative growth rate(RGR) was markedly higher under the high light level than under the low light level. Enrichment with NH 4 + enhanced the RGR under high light intensity, but did not affect RGR under low light intensity. In low light conditions, NH 4 +-enrichment resulted in a marked decrease in the maximal photosynthetic rate( P m) and the maximum carbon fixation rate( V max), but it did not affect the half saturation constant for carbon( K 0.5) or the ratio of V max to K 0.5, which reflects the carbon acquisition efficiency. In high light conditions, P m, K 0.5, and the dark respiration rate( R d) increased under NH 4 + enrichment, but V max and the V max / K 0.5 ratio decreased. Regardless of the light intensity, NH 4 +-enrichment did not affect the apparent photosynthetic efficiency( α), which refl ects the ability of the alga to use light energy at low light levels. Under both low and high light intensities, the chlorophyll a(Chl a), chlorophyll b(Chl b), and carotenoids(Car) contents in thalli were higher in NH 4 +-enriched than in natural seawater, except that there was a decrease in the Chl b content of thalli in NH 4 +-enriched seawater under low light intensity. Therefore, NH 4 + enrichment improved the growth and photosynthetic performance of U. prolifera under high light intensity, but not under low light intensity. We discuss the possible mechanisms underlying these physiological responses.  相似文献   

17.
Substrate is a critical environmental factor affecting the activity of bivalves. To examine the effect of the substrate component on the growth and survival of juvenile sunray surf clam(Mactra chinensis Philippi), a series of short-term experiments were conducted using a variety of substrates with different ratios of sand to mud. The experimental group cultured without substrate showed poor survival, with all juveniles died after day 20. The juveniles cultured in mud without sand showed a lower survival rate(25.54% ± 0.40% on day 45) than those in other groups. The juveniles cultured in sand without mud, or the mixtures of sand and mud with a ratio of 1:1 and 2:1, respectively, exhibited modest survival at day 45. Maximal weight gain rate(WGR), shell length growth rate(LGR), and specific growth rate(SGR) were observed when the sand concentration was 61.97%, 77.69%, and 64.64%, respectively. As the fast growth and high survival were observed when the sand to mud ratio was 1:1(50% sand) and 2:1(67% sand), a sand concentration of more than 50% is optimal. The optimal concentration of sand in the substrate for rearing juvenile sunray surf clams was 67% which resulted in the fastest growth and highest survival. These results can be used to developing a nursery/farming technique of improving the yield of sunray surf clams.  相似文献   

18.
大珠母贝术后处理研究   总被引：1，自引：0，他引：1  
用蚌复康（A组）、鱼蚌康复剂（B组）和盐酸普鲁卡因（C组）对人工插核后的大珠母贝进行术后处理，并经室内人工管养度过休养期。结果显示：术后成活率C组为70．0％，A组为60．0％，对照组为364％；留核率A组为66.7％，C组为57.1％，对照组为50.0％。表明蚌复康与盐酸普鲁卡因可以明显提高植核母贝的术后成活率和留核率；另外，休养期在室内度过也有助于提高留核率。  相似文献   

19.
To study population dynamics of marine ciliates in different artificial seawaters (ASW), the population growth dynamics of a common marine ciliate Euplotes vannus were investigated using beef extract media and rice media for five types of ASW and natural seawater (NSW). The results show that: (1) the population growth rate was in the order of NSW>Flack ASW>Nakamula ASW>Schmadz ASW>Oshima ASW>Subow ASW and was considerably higher in rice media than in beef extract media (apart from Subow ASW); (2) the maximum density of E. vannus in stationary phase in each treatment was ranked as Flack ASW>Nakamula ASW>Schmadz ASW>NSW>Oshima ASW>Subow ASW, and was again higher in rice media than in beef extract media (except for Subow ASW); (3) the exponential and stationary phases were longer in rice media than in beef extract media; (4) strains of E. vannus that had been domesticated for >1 year in ASW grew significantly slower, with lower maximum density and longer stationary phase than those isolated and maintained in NSW. It was demonstrated that: (1) E. vannus may grow well in Flack, Nakamula and Schmads ASW compared with NSW (mainly in terms of growth rate); and (2) Oshima ASW is the preferred choice for stock cultures of E. vannus, but the ASWs Flack, Nakamula and Schmadz are preferred for mass culture. These findings suggest that these three ASWs are effective for the cultivation of marine protozoa for experimental studies on ecology, toxicology and molecular biology.  相似文献   

20.
With the decline in the most fisheries resources in the Yellow Sea,the yellow goosefish Lophius litulon has increased in commercial and ecological importance in recent years.We studied the length distribution,length-weight relationship,age composition,growth pattern,mortality,and exploitation rates of the yellow goosefish in the Yellow Sea.Total length(TL) of females and males ranged from 173 to582 mm and 178 to 500 mm,respectively.The length-weight relationships were also estimated for females and males.Age classes from 2 to 4 years predominated in the samples.The von Bertalanffy growth function(VB GF),estimated based on non-linear least-squares methodology,showed significant differences between sexes.Females attained a greater estimated asymptotic total length(765 mm TL) compared to males(579 mm TL).The VBGF did not differ significantly between stocks of the northern Yellow Sea and the southern Yellow Sea.Estimated natural instantaneous mortality rate(M) ranged from 0.25/a to 0.33/abased on four age-and length-based methods.Total instantaneous mortality rate(Z) of total samples calculated by the age-based catch curve method was 0.591/a and the average fishing mortality(F) was 0.30/a.Estimated exploitation rate(E) was approximately 0.5,indicating that the population of L.litulon in the Yellow Sea may be sustainable.These results provide a reference for the present status of L.litulon and information for the management.  相似文献   

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