配合饲料中添加玉米DDGS对刺参(Apostichopus japonicus)生长、体组成及免疫指标的影响

在基础饲料中分别添加0、10%、20%、30%、40%的玉米干酒精糟及其可溶物(Dried distiller's grains with solubles,DDGS),配制成5种等氮等能的实验饲料(DDGS0、DDGS10、DDGS20、DDGS30和DDGS40),饲喂初始体重为(9.69±0.28)g的刺参56 d,研究玉米DDGS作为替代蛋白源对其生长、体成分及免疫指标的影响。结果显示,随着玉米DDGS添加水平的升高,刺参增重率和特定生长率略有下降,但各组间差异不显著(P0.05)。各实验组刺参体壁指数、肠道指数、肠长比以及体壁水分、粗蛋白、粗脂肪和粗灰分含量均不受玉米DDGS添加的影响(P0.05)。体腔液中溶菌酶的活性呈先上升后稳定的趋势,其中,DDGS20和DDGS40组显著高于DDGS0和DDGS10组(P0.05),DDGS30组与其他各组无显著差异(P0.05)。酸性磷酸酶的活性呈先上升后下降的趋势,在DDGS20组达到最大值,其中,DDGS20组显著高于其他各组(P0.05),DDGS40组显著高于DDGS0组(P0.05),其他各组间无显著差异(P0.05)。酚氧化酶的活性随着DDGS添加量的增加呈上升趋势,各添加组均显著高于DDGS0组(P0.05),DDGS40组显著高于DDGS10组(P0.05),其他各组间无显著差异(P0.05)。饲料中添加玉米DDGS对体腔液中碱性磷酸酶和超氧化物歧化酶的活性无显著影响(P0.05)。本研究表明,饲料中添加0–40%的玉米DDGS均不影响刺参的生长和体壁成分,且添加20%–40%的玉米DDGS能提高刺参体腔液中免疫酶的活性。     

饲料中添加甘薯(Ipomoea batatas)块根与茎蔓对刺参(Apostichopus japonicus)生长和非特异性免疫力的影响

在刺参(Apostichopus japonicus)配合饲料中添加不同比例(10％、20％、30％、40％、50％、60％)的甘薯块根粉与甘薯茎蔓粉,测定了添加2种甘薯饲料成分对刺参生长和非特异性免疫力的影响.结果显示,在50 d实验期间,投喂添加甘薯块根粉饲料的实验组刺参平均体重随实验时间呈上升趋势,实验结束时,添加20％甘薯块根粉组终末体重显著高于对照组(P＜0.05),10％、30％组特定生长率(SGR)与对照组差异不显著(P＞0.05);投喂添加10％甘薯茎蔓粉的实验组刺参SGR与对照组差异不显著(P＞0.05),其余各组SGR均低于对照组(P＜0.05).投喂添加10％、20％甘薯块根粉饲料的实验组刺参体腔液中过氧化氢酶(CAT)、酸性磷酸酶(ACP)、碱性磷酸酶(AKP)均显著高于对照组(P＜0.05);投喂添加10％甘薯茎蔓粉饲料的实验组ACP显著高于对照组(P＜0.05),刺参体腔液中的溶菌酶(LZM)、总超氧化物歧化酶(T-SOD)、CAT和AKP与对照组差异不显著(P＞0.05).研究表明,当甘薯块根与茎蔓的添加比例分别在30％和20％以下时,可满足刺参的营养需求,促进或保证刺参的生长,提高刺参免疫能力.     

两种甘薯饲料原料的营养成分及其对仿刺参(Apostichopus japonicus)摄食与生长的影响

在刺参配合饲料中添加6个比例(10％、20％、30％、40％、50％、60％)的甘薯块根粉与甘薯蔓茎粉,测定两种甘薯饲料原料的营养成分及其对仿刺参摄食与生长的影响.结果显示,甘薯块根粉中粗蛋白含量为10.01％,甘薯蔓茎粉中粗蛋白含量为5.54％;每100 g甘薯块根与蔓茎粉中氨基酸总量分别为7.33 g和4.37 g.在30 d的实验期间,投喂添加甘薯块根粉饲料的实验组仿刺参平均体重随实验时间呈上升趋势,实验结束时,10％和20％组特定生长率(SGR)显著高于对照组(P＜0.05), 30％组SGR与对照组差异不显著(P＞0.05).投喂添加10％甘薯蔓茎粉的实验组仿刺参SGR与对照组差异不显著(P＞0.05),其余各组SGR均低于对照组(P＜0.05).投喂添加10％、20％甘薯块根粉饲料的实验组仿刺参食物转化率(FCE)显著高于对照组(P＜0.05),投喂添加10％甘薯蔓茎粉饲料的实验组FCE与对照组差异不显著(P＞0.05),其余各实验组仿刺参FCE显著低于对照组(P＜0.05).结果表明,当甘薯块根粉和甘薯蔓茎粉添加比例分别低于30％和10％时,可满足刺参的营养需求,提高饲料利用效率,保证并促进仿刺参的摄食与生长.     

不同浒苔型饲料对幼刺参(Apostichopus japonicus)生长、消化及非特异性免疫的影响

以浒苔、石莼、豆粕、扇贝边、葡萄糖、贝壳粉、维生素和矿物质预混料为原料配制刺参(Apostichopus japonicus)饲料,利用酿酒酵母菌菌液和碱性蛋白酶制剂对刺参饲料进行4种不同的处理,得到5组实验用饲料,分别为对照组、发酵组、酶解组、复合组和鲜浒苔组.将上述饲料饲喂初始体重为(1.92-0.02)g的幼刺参42 d,每种饲料设3个重复,每个重复30头幼刺参.结果显示,不同的浒苔型饲料对幼刺参的存活率(SR)、增重率(WGR)、特定生长率(SGR)和饲料系数(FC)有显著影响(P＜0.05),而对其脏壁比(R)无显著性影响(P＞0.05).复合组和鲜浒苔组SR要显著高于酶解组(P＜0.05),而与其他2组均无显著性差异(P＞0.05).鲜浒苔组WGR远高于其他各组(P＜0.05),而复合组和发酵组WGR显著高于酶解组(P＜0.05),与对照组差异不显著(P＞0.05).幼刺参的SGR规律与WGR一致.鲜浒苔组FC显著低于对照组、发酵组和酶解组(P＜0.05),与复合组差异不显著(P＞0.05).随着摄食饲料时间的推移,对照组、发酵组、复合组和鲜浒苔组淀粉酶(AMS)活力先升高再下降后趋于稳定,而酶解组一直呈现下降趋势.酶解组纤维素酶(Cellulase)活力呈现一直下降的趋势,而其他组呈现波动变化,且均高于初始活力值.随着摄食饲料时间的推移,除酶解组外,其余各组胰蛋白酶(TRY)活力前后时间点变化差异不大,且每个采样点幼刺参TRY活力大小顺序始终是对照组＞复合组＞鲜浒苔组＞发酵组＞酶解组.不同浒苔型饲料饲喂的幼刺参体腔液中酸性磷酸酶(ACP)、碱性磷酸酶(AKP)和超氧化物歧化酶(SOD)活力均有显著性差异(P＜0.05).鲜浒苔组ACP活力最大,且与复合组无显著性差异(P＞0.05),而显著高于其他3组(P＜0.05).鲜浒苔组和复合组AKP活力显著高于酶解组和对照组(P＜0.05),与发酵组无显著性差异(P＞0.05).复合组SOD活力最大,且显著高于发酵组和酶解组(P＜0.05),而与对照组和鲜浒苔组均无显著性差异(P＞0.05).由此得出,幼刺参在摄食先酶解后发酵的饲料后能够得到良好的生长效果,并可改善自身肠道消化,维持正常免疫.这为解决刺参饲料原料短缺以及浒苔高值化利用提供了依据和方法.     

不同分子量壳聚糖对刺参(Apostichopus japonicus Selenka)生长和免疫功能的影响

以初始体重为(6.77±0.01)g的仿刺参(Apostichopus japonicus Selenka)为实验对象,在基础饲料中添加1％不同分子量的壳聚糖,分子量分别为35 kDa和400 kDa,进行为期56d的养殖实验,研究低分子壳聚糖(LMWC)和高分子壳聚糖(HMWC)对仿刺参生长和免疫相关酶活性的影响.结果显示,不同分子量的壳聚糖对仿刺参的生长均有促进作用,且LMWC能显著促进刺参的特定生长率(SGR)(P＜0.05).饲料中添加不同分子量壳聚糖,刺参体腔细胞中的总超氧化物歧化酶(T-SOD)活性比对照组均显著增高(P＜0.05).LMWC可显著增强刺参体腔细胞中酸性磷酸酶(ACP)活性(P＜0.05),并能提高碱性磷酸酶(AKP)和一氧化氮合酶(NOS)活性.HMWC对刺参体腔细胞中AKP和NOS活性均有显著增强作用(P＜0.05).研究表明,在刺参饲料中添加一定量的壳聚糖,对其生长和相关免疫酶活性有促进作用.     

不同投喂水平对刺参(Apostichopus japonicus Selenka)生长、消化酶及免疫相关酶活性的影响

试验研究了饥饿、次饱食、饱食和过饱食4个不同投喂水平(即2％、3％、4％和5％体重)对刺参[初始体重为(5.80±0.02)g]生长性能、体成分、消化性能以及刺参体壁与体腔液内超氧化物歧化酶(SOD)、碱性磷酸酶(AKP)和溶菌酶(LZM)活性的影响.试验在室内静水养殖系统中进行,试验水温为19-21℃,为期60 d.结果显示,在次饱食水平下,刺参特定生长率达到最高,显著高于饥饿水平和过饱食水平(P＜0.05),但与饱食水平差异不显著(P＞0.05);刺参肠道胰蛋白酶活性均随着投喂水平的提高而升高,在过饱食水平下达到最高,显著高于饥饿水平和次饱食水平(P＜0.05),但与饱食水平差异不显著(P＞0.05);刺参肠道淀粉酶活性随着投喂水平的提高呈现先下降后保持稳定的趋势,在饱食水平之后达到稳定;在饱食水平下,刺参体壁和体腔液AKP、SOD及LZM活性均表现出较高水平,表明在饱食投喂水平下,刺参抗病能力最强;不同投喂水平对刺参体壁营养组成以及刺参脏壁比均无显著影响(P＞0.05).因此,建议刺参养殖采用饱食水平进行投喂.     

饲料中添加南极磷虾粉对半滑舌鳎(Cynoglossus semilaevi)雄性亲鱼繁殖性能及抗氧化功能的影响

饲料中添加0、10％、20％的南极磷虾粉,配制3组(对照组K-0、K-10、K-20)等氮等脂的实验饲料,在室内流水养殖系统进行为期90 d的养殖实验,探讨南极磷虾粉对半滑舌鳎(Cynoglossus semilaevis)雄鱼繁殖性能和抗氧化能力的影响.结果显示,饲料中添加南极磷虾粉对半滑舌鳎雄鱼肝体比、性体比、精液浓度、睾酮含量均无显著性影响(P＞0.05);K-10组与K-20组精巢中超氧化物歧化酶(SOD)活性无显著性差异(P＞0.05),但均显著高于对照组(P＜0.05),K-10组与K-20组精巢、血清和肝脏中的丙二醛(MDA)含量无显著性差异(P＞0.05),但均显著低于对照组(P＜0.05).在本实验条件下,饲料中添加南极磷虾粉不能显著提高半滑舌鳎雄鱼的繁殖性能(P＞0.05),但能显著提高雄鱼的抗氧化功能(P＜0.05).     

海星棘皮作为仿刺参饲料添加成分的可行性

对海星棘皮作为仿刺参饲料添加成分的可行性进行初步研究。将海星棘皮干粉按0%、10%、20%、30%、40%的替代比例添加于以鱼粉、马尾藻(Sargassum muticum)、浒苔(Enteromorpha prolifera)为原料的基础饲料中,投喂体质量为3.4~4.0 g的仿刺参(Apostichopus japonicas)幼参60 d,结果表明,各组仿刺参生长良好,成活率无显著差异(P0.05);在60 d时,20%、30%和40%饲料组的仿刺参平均增重率、特定生长率显著高于0%和10%饲料组(P0.05);20%饲料组仿刺参的特定生长率最高,与30%和40%饲料组差异不显著(P0.05)。从饲料系数和摄食率看,0%和10%饲料组的饲料系数、摄食率最高,显著高于20%、30%、40%饲料组(P0.05),20%和30%海星饲料组的饲料系数、摄食率最低,二者差异不显著(P0.05),与40%饲料组差异显著(P0.05)。结果表明,添加20%~30%海星棘皮干粉饲料可促进仿刺参的生长和提高饲料的利用。     

青、白刺参(Apostichopus japonicus)体壁营养成分的比较分析

通过对相同养殖环境条件下,青、白刺参(Apostichopus japonicus)体壁中营养成分(粗蛋白、粗脂肪、多糖、脂肪酸、氨基酸、微量元素等)的测定,比较两种剌参的营养品质与价值.结果显示,青、白刺参的出皮率,体壁中的水分、多糖和灰分含量差异显著(P＜0.05),粗蛋白和粗脂肪差异不显著(P＞0.05).青、白刺参体壁中均检测出20种主要脂肪酸,脂肪酸总量和多不饱和脂肪酸(PUFA)的含量差异不显著(P＞0.05),而青刺参饱和脂肪酸(SFA)含量显著高于白刺参,单不饱和脂肪酸(MUFA)含量显著低于白刺参(P＜0.05).MUFA中青刺参的花生四烯酸(AA)和二十二碳六烯酸(DHA)含量均显著低于白刺参(P＜0.05).青、白刺参体壁中检测出17种氨基酸,必需氨基酸(EAA)、鲜味氨基酸(FAA)和药效氨基酸(DAA)的含量均无显著差异(P＞0.05).青刺参体壁中天冬氨酸和精氨酸含量均显著低于白刺参(P＜0.05).青刺参体壁中Mn和Cr的含量显著低于白刺参(P＜0.05).重金属元素Pb、Cd、Hg、As的含量均符合相关食品卫生标准.综合评价认为,相同养殖环境条件下,白刺参的出皮率、多糖含量、脂肪酸中不饱和脂肪酸含量、AA和DHA的相对百分含量、氨基酸中天冬氨酸和精氨酸含量以及微量元素中Mn和Cr含量均优于青刺参.     

饲料中添加甘薯(Ipomoea batatas)块根与茎蔓对刺参(Apostichopus japonicus)生长和非特异性免疫力的影响

在刺参(Apostichopus japonicus)配合饲料中添加不同比例(10%、20%、30%、40%、50%、60%)的甘薯块根粉与甘薯茎蔓粉,测定了添加2种甘薯饲料成分对刺参生长和非特异性免疫力的影响。结果显示,在50 d实验期间,投喂添加甘薯块根粉饲料的实验组刺参平均体重随实验时间呈上升趋势,实验结束时,添加20%甘薯块根粉组终末体重显著高于对照组(P0.05),10%、30%组特定生长率(SGR)与对照组差异不显著(P0.05);投喂添加10%甘薯茎蔓粉的实验组刺参SGR与对照组差异不显著(P0.05),其余各组SGR均低于对照组(P0.05)。投喂添加10%、20%甘薯块根粉饲料的实验组刺参体腔液中过氧化氢酶(CAT)、酸性磷酸酶(ACP)、碱性磷酸酶(AKP)均显著高于对照组(P0.05);投喂添加10%甘薯茎蔓粉饲料的实验组ACP显著高于对照组(P0.05),刺参体腔液中的溶菌酶(LZM)、总超氧化物歧化酶(T-SOD)、CAT和AKP与对照组差异不显著(P0.05)。研究表明,当甘薯块根与茎蔓的添加比例分别在30%和20%以下时,可满足刺参的营养需求,促进或保证刺参的生长,提高刺参免疫能力。     

Abundance and culture trials of Ruditapes philippinarum (Adam and Reeve, 1850), and abundance of Tellina (Quidnipagus) palatum (Iredale, 1929) at two sites in Kāne'ohe Bay,O'ahu,Hawai'i

Abundance, length‐frequencies and distribution of Ruditapes philippinarum (Manila Clams) and Tellina (Quidnipagus) palatum were measured at two beaches in Kāne'ohe Bay, O'ahu, Hawai'i in June, 2010. Abundances had decreased from 866.2 m^?2 to 3.4 m^?2 for Ruditapes and from 75.5 m^?2 to 1.5 m^?2 for T. palatum since 1977. Distribution of both species was patchy, but both were most commonly found >40 m from shore. Size frequencies of live clams compared with empty shells suggest that few Ruditapes survive to sexual maturity. A similar trend was not detected for T. palatum. Aquaculture trials of R. philippinarum were conducted at the He'eia and Moli'i traditional Hawaiian fishponds in the same bay. The clams failed to thrive, although triploid and diploid Crassostrea gigas performed well in concurrent trials in the same fishponds. Current lower abundances for wild R. philippinarum could be due to factors related to predation or nutrient limitations. Previously, two large sewage outfalls existed at the surveyed clam bed areas which may have temporarily increased nutrient availability for both wild and cultured clams. Current nutrient levels may inhibit Manila clam growth and recruitment in Kāne'ohe Bay.     

WSSV-VP39基因克隆与结构分析

根据已公布的WSSV-VP39全基因序列(GenBank No.AAL89161)设计1对引物,经PCR扩增及琼脂糖凝胶电泳分析,扩增出约898bp的特异条带,将其回收后克隆入pGAPZα-A载体中,并进行序列测定与分析。结果表明,扩增序列与Gene Bank登录序列(GenBank No.AAl89161)核苷酸同源性100%。序列分析表明,WSSV-VP39基因编码蛋白无跨膜区域,有多个蛋白激酶C、酪蛋白激酶Ⅱ磷酸化位点和酪氨酸硫酸化位点,1个糖基化位点。蛋白序列比对结果表明,WSSV-VP39与WSSV-VP37具有较高的同源性,其在WSSV侵染中的作用值得关注。     

Ontogenic development of enzymatic activity and digestive system in Jullien's golden carp (Probarbus jullieni Sauvage, 1880)

Ontogenic development of the main enzymes and histological structure of digestive organs were studied in Jullien's golden carp (Probarbus jullieni) from hatching until 50 days after hatching (DAH). The larval fish were produced by artificial insemination and fed only Moina sp. till end of experiment. Body weight (mg) and total length (cm) of Jullien's golden carp increased exponentially and linearly. The results indicate the fish weight grew fast with increasing rate, while length increased at a constant rate over the studied period. Up‐regulation of acid protease was observed in newly hatched larvae and the specific activity gradually decreased with time. Trypsin specific activity was relatively stable within the first 35 DAH, while fluctuations in chymotrypsin were observed. Among these three proteolytic enzymes, acid proteases exihibited relatively high specific activity in newly hatched larvae, suggesting a role in yolk protein degradation. Alkaline proteases became more prominent with age and correlated with an abrupt decrease in acid proteases. Increased lipase‐specific activity appeared within 3 DAH and then gradually decreased with time, indicating the capacity to digest yolk lipid reserve. Amylase and cellulase‐specific activities changed in a similar manner, and the sensitivity to time was higher in amylase than in cellulase. The digestive organs and accessory organs developed around 3–5 DAH. However, intestinal histology was almost fully developed around 18 DAH. These findings should be useful for deciding the preferred timing for weaning, as well as on developing artificial diets referenced to the physiological changes of digestive enzymes.     

The loss of genetic diversity in Dabry's sturgeon (Acipenser dabryanus,Dumeril) as revealed by DNA fingerprinting

• 1. Dabry's sturgeon, a large, long‐lived migratory fish is endemic to the Yangtze River. Over‐fishing and habitat destruction have caused large‐scale declines in natural stocks in the last two decades.
• 2. Examining patterns of genetic diversity has become an integral component of many management plans for endangered species. DNA fingerprinting was applied to detect genetic diversity in Dabry's sturgeon collected in 1958–1959, 1980–1981 and 1998–1999.
• 3. Studies on direct genetic parameters (genetic variability, hypervariable loci and heterozygosity) and indirect parameters (band‐sharing coefficient and allelic frequency) showed that the continuous decline in wild populations has caused the loss of genetic diversity in present‐day sturgeon.
• 4. The present‐day populations have the lowest genetic variability; thus, effective management is needed to preserve genetic diversity.
• 5. A conservation strategy is urgently required, comprising artificial rearing facilities coupled with breeding management plans.

Copyright © 2003 John Wiley & Sons, Ltd.     

Partial replacement of fishmeal by brewer's yeast (Saccharomyces cerevisiae) in the diets of Thai Panga (Pangasianodon hypophthalmus × Pangasius bocourti)

Feeding trials were carried out to evaluate the efficacy of the replacement of fishmeal with brewer's yeast (Saccharomyces cerevisiae) in the diets of Thai Panga (Pangasianodon hypophthalmus × Pangasius bocourti). Thai Panga juveniles with an average initial weight of 36.4 ± 0.07 g were randomly stocked in cages (1 × 1 × 1.5 m³) at a rate of 40 fish per cage. Experimental diets were formulated to provide isonitrogenous (320 g kg^?1 CP) and isocaloric (15.30 kJ g^?1) diets, by increasing brewer's yeast levels to replace 30%, 45%, 60% or 75% of dietary fishmeal. The control groups were comprised of the commercial feed (CA) and the basal diet without brewer's yeast (CB). Fish were rearing for 9 months. The final weights, weight gains, specific growth rate and daily growth rate showed that brewer's yeast can be used effectively as a substitute for up to 45% of the fishmeal. The replacement of fishmeal by brewer's yeast did not affect the feed efficiency, blood haematology and meat quality (P > 0.05). Alternative complement activity (ACH50), lysozyme activity and total immunoglobulin (Ig) in the fish in groups that had replacement feed diets were significantly higher than those of control group. Replacing 45% of fishmeal with brewer's yeast can improve the growth performance and immune response of the Thai Panga.     

Habitat differentiation between sei (Balaenoptera borealis) and Bryde's whales (B. brydei) in the western North Pacific

Two closely related baleen whale species, sei and Bryde's whales, in the western North Pacific were studied to identify differences in habitat use. Data were obtained from May to August 2004 and 2005. This study examined the relationship between oceanographic features derived from satellite data and the distribution of sei and Bryde's whales using basic statistics. We investigated oceanographic features including sea surface temperature (SST), sea surface chlorophyll a (Chl‐a), sea surface height anomalies (SSHAs), and depth of the habitat. These two whale species used habitats with different SST, Chl‐a, and SSHA ranges. The 0.25 mg m^?3 Chl‐a contour (similar to the definition of the Transition Zone Chlorophyll Front) was a good indicator that separated the habitats of sei and Bryde's whales. Then generalized linear models were used to model the probabilities that the whale species would be present in a habitat and to estimate their habitat distribution throughout the study area as a function of environmental variables. The potential habitats of the two species were clearly divided, and the boundary moved north with seasonal progression. The habitat partitioning results indicated that SST contributed to the patterns of habitat‐use and might reflect differences in prey species between the two whales. This study showed that the habitats of the sei and Bryde's whales were clearly divided and their potential habitat‐use changed seasonally.     

Effect of dietary vitamin C on growth performance,body composition and biochemical parameters of juvenile Chu's croaker (Nibea coibor)

Vitamin C is an essential micronutrient for normal physiological and immune functions of fish. However, its requirements and effects in Chu's croaker (Nibea coibor) are currently unknown. A 56‐day feeding trial was conducted to evaluate the optimal dietary vitamin C requirements based on its effects on growth performance, body composition and biochemical parameters in juvenile Chu's croaker (14.17 ± 0.1 g). Six isoproteic (450 g/kg crude protein) and isolipidic (100 g/kg crude lipid) diets were formulated to contain 2.24 (basal diet), 39.03, 85.01, 171.16, 356.49 and 715.46 mg/kg of vitamin C. The results showed that fish fed on 171.16 mg/kg vitamin C diet had the highest growth performance and feed utilization. Fish fed on the basal diet had higher malondialdehyde (MDA) content and lower activities of antioxidant enzymes in the serum and liver as compared with those fed on vitamin C diets. Polynomial analysis indicated that the optimal dietary vitamin C requirements of juvenile Chu's croaker were 102.28, 98.21, 150.26, 165.38, 71.46, 176.19, 84.84 and 103.78 mg/kg based on weight gain, specific growth rate, liver storage, muscle storage, liver MDA content, liver alanine aminotransferase activity, liver alkaline phosphatase activity and liver superoxide dismutase activity, respectively. We recommend an inclusion level in the range of 71.46–150.26 mg/kg vitamin C in the diets of juvenile Chu's croaker for optimum growth performance, liver function, antioxidant capacity and innate immunity functions.     

Pathological effects of Cichlidogyrus philander Douëllou, 1993 (Monogenea,Ancyrocephalidae) on the gills of Pseudocrenilabrus philander (Weber, 1897) (Cichlidae)

Histopathological changes of Cichlidogyrus philander Douëllou, 1993 on the gills of Pseudocrenilabrus philander (Weber, 1897) were studied using light and scanning electron microscopy. Observations revealed that C. philander attaches to its host by alternating the prohaptor (for temporary attachment or feeding) or haptor (using haptoral parts for firm and secured attachment). The sharp terminal ends of the anchors are inserted basally into the gill lamella, between two adjacent secondary gill lamellae and the marginal hooklets assist by superficially penetrating, holding and lifting epithelial tissue in the proximal region of the secondary gill lamella. The attachment of C. philander resulted in compression, rupturing of the interlamellar epithelium, change in the organization of epithelial cells in both primary and secondary gill lamella, displacement of the extracellular cartilaginous matrix, occasional rupturing of blood vessels and erythrocytes and some cells becoming ill-defined. At the site of attachment, the host response comprises of hyperplasia, increase in the number of mucous cells and infiltration with neutrophils. It was concluded that the effect of C. philander is mild in natural conditions.     

The application of tannic acid to the elimination of egg stickiness at varied moments of the egg swelling process in pikeperch,Sander lucioperca (L.)

The aim of this article was to analyse the process of pikeperch, Sander lucioperca, egg swelling and to apply tannic acid to eliminate egg stickiness at different moments of the swelling process on artificially obtained eggs. The first experiment involved observation of egg swelling process and the second determined the effect of temperature (12, 14 and 16°C) on the egg swelling rate. The third experiment involved elimination of egg stickiness in a tannin solution (0.75 g L^?1) where eggs were submerged in a solution for 0.5, 1, 2 and 5 min – 5, 10, 15, 20, 25 and 30 min following gamete activation. The results indicate that the pikeperch egg swelling process lasts 30 min. It was found that the temperature did not affect the process duration. The results of the third experiment showed that the effectiveness of tannic acid application in egg stickiness elimination increases with time. The best result was obtained in groups of eggs submerged for 1 and 2 min (86.5% and 80.5% of larvae were obtained respectively) 30 min following the gamete activation. The results presented in this study for the first time indicate the possibility of highly effective procedure of egg stickiness elimination with tannic acid in pikeperch aquaculture.     

温度对虾夷扇贝幼体和稚贝生长,成活率的影响

在１５．０℃、１７．５℃和１９．０℃３个温度梯度下，各试验组纪体的生长速度和成活率６．３μｍ／ｄ，８．６μｍ／ｄ、９．３μｍ／ｄ；６１．０％、７０．５％、２３．０％。投附着基经２２ｄ培养各试验组稚贝规格（壳长×壳高）分别平均为６２０μｍ×５９５μｍ、７０５μｍ×６８０μｍ、７４５μｍ×７１０μｍ；各组生长速度和附着后成活率分别为１７．７μｍ／ｄ、２１．６μｍ／ｄ、２３．４μｍ／ｄ；３５．４％、３４