跑道式对虾养殖生态系主要生态因子研究

对广西海洋研究所古城海水增养殖试验基地的跑道式养殖池进行了一茬南美白对虾养殖主要生态因子的跟踪监测。结果表明,养殖水体中的异养菌、弧菌具有明显不同的变化趋势,异养菌在养殖前、后期稍低,中期高;弧菌为前期低,后期高且变化幅度大。异养菌为8.02×103~6.15×104cfu/m l,弧菌为1.50×10~1.42×104cfu/m l,对照的蓄水池异养菌、弧菌为1.0×103cfu/m l;养殖池的pH值为7.1~8.8,溶解氧为1.48~3.75 mg/L,皆为前期高,后期低。盐度前期约为33.8,其后则在18.1~24.6变化,氨氮为0.2~1.5 mg/L,亚硝酸盐在养殖前期<0.01 mg/L,后期>0.3 mg/L;异养菌、弧菌与各理化因子之间不具明显的线性相关;在养殖过程中,养殖对虾没有检测到白斑综合征病毒。     

芽孢杆菌对弧菌的抑制作用及其应用

采用牛津杯抑菌圈检测法,探讨了4株芽孢杆菌(K、S、BA、SN)代谢产物对溶藻弧菌的抑制能力,用三角烧瓶稀释法模拟养殖水体,探讨了枯草芽孢杆菌SN对溶藻弧菌的抑制效果.结果显示,K、S、BA没有抑菌活性,SN有明显抑菌活性,在模拟养殖水体中,104~l06 cfu/ml的SN溶液对溶藻弧菌有明显的抑制作用,其抑制作用随溶藻弧菌菌量的增大而减弱.进一步尝试用SN培养液来控制鲍养殖池中底栖硅藻上弧菌的数量,104 cfu/ml的SN对弧菌有较好的抑制作用.     

九孔鲍养殖水体及消化道细菌学的研究

2002年对汕尾健生鲍鱼养殖场养殖水体和鲍消化道中异养细菌及弧菌的数量和类群组成进行了研究。研究结果表明:养殖水体中异养细菌数量的四季变化从2 4×104～1 3×105cfu ml,平均为7 6×104cfu ml;消化道中异养细菌数量四季变化则从1 6×107～5 4×107cfu g(湿重),平均为3 3×107cfu g。水体中弧菌数量四季变化从1 2×104～5 1×104cfu ml,平均为2 5×104cfu ml;而消化道中弧菌数量四季变化则从2 8×105～3 8×105cfu g,平均为3 2×105cfu g。水体中细菌类群由Sphingomonas,Vibrio,Pasteurella,Moraxella,Pseudomonas,Aeromonas,Flavobacterium,Klebsiella,Weeksella和Alcall组成,消化道中细菌类群由Sphingomonas,Vibrio,Aeromonas,Flavobacterium,Shewanella,Sphingobacterium,Pseudomonas组成,水体和消化道弧菌种类主要为Vibriofluvialis,Vibrioparahaemolyticus,Vibriovulnificus,Vibriocholerae,Vibriominicus,Vibrioalginolyticus。并对不同养殖场水源弧菌数量也进行了比较。     

锯缘青蟹养殖环境中细菌类群及其数量分布

研究了锯缘青蟹养殖环境中细菌类群及其数量在垂直与季节上的变化规律.试验结果表明,异养细菌的组成类群在水体与底泥中基本相似,其中水体以革兰氏阴性菌为主,占87.2 %,底泥中以革兰氏阳性菌为主,占64.5 %;水体中菌量为5.3×10～6. 6×104 cfu/ml,9月达到高峰,底泥中菌量为7.8×103～3.5×105 cfu/g,高峰出现在11月.水体中弧菌量为1.4×10～8.6×103 cfu/ml,9月达到高峰,底泥中弧菌为6.8×102～1.33 ×104 cfu/g,9-10月维持在较高水平.氨化细菌、反硝化细菌、硫酸还原菌在9-11月初均维持较高水平,三者在底泥中于11月初达到高峰,提示该时期底泥环境已发生恶化.     

TCBS培养基在虾病防治监测中的应用

TCBS培养基是医学临床上分离致病弧菌的常用方法,而在对虾养殖生产中,也可以顺利达到分离弧菌的目的。对虾养殖池水质监测中,如果水中弧菌菌群数量在TCBS培养基上大量增加,由100个/ml以上,突然增加到300～500个/ml时,养殖池水也一定会发生很大的变化。当弧菌在水中形成优势种群,在虾体内达到致病量的时间约需1～2周。     

高位虾塘细菌数量变化特点及其与理化因子的关系

本试验选取两口凡纳滨对虾高位池塘,通过连续地周期性采样和测定分析,研究了虾池异养细菌数量和弧菌数量变动规律及其与理化因子的相关关系。结果表明：两口试验虾池异养细菌数量变化范围在9.07×10^3～2.13×10^5 cfu/mL之间,平均为6.45×10^4 cfu/mL,呈现持续缓慢上升的趋势;两口试验虾池的弧菌数量变化趋势较为一致,变化范围为2.12×10^2～2.91×10^3 cfu/mL,养殖生产前期较低,中期高,后期随着换水量的加大而有所下降。相关性分析表明：虾池水体的异养细菌和弧菌数量均与透明度、 DO、 pH 呈负相关,与COD、 TSS含量呈正相关,其中弧菌数量与TSS含量呈显著正相关（ P〈0.05）。     

凡纳滨对虾高位池养殖水体细菌变动及其与理化因子的关系

自2008年4月至8月,在广东省汕尾市红海湾凡纳滨对虾（Litopenaeus vannamei）高位池养殖基地全程采集养殖池塘水样,检测水体细菌类群和理化因子,分析养殖过程中细菌类群的数量变化规律及其与环境因子的关系。结果显示,养殖过程中水体异养细菌、弧菌（Vibrio）和芽孢杆菌（Bacillus）的数量波动性较大,其中异养细菌波动范围1.35×10^4～1.39×10^6cfu·mL^-1,平均4.73×10^5cfu·mL^-1;弧菌波动范围1.05×10^3～5.20×10^4cfu·mL^-1,平均1.80×10^4cfu·mL^-1;芽孢杆菌波动范围0.11×10^3～4.30×10^3cfu·mL^-1,平均6.6×10^2cfu·mL^-1;粪大肠菌群（fecalcoliform）大多在1.0×10^2cfu·L^-1以内,平均0.97×10^2cfu·L^-1,远低于无公害食品海水养殖用水水质标准。对细菌与理化因子的单因子分析显示,异养细菌与溶解氧（DO）呈显著的负相关性（P〈0.05）,弧菌与pH呈极显著的负相关性（P〈0.01）,与化学需氧量（COD）和总磷（TP）呈显著的正相关性（P〈0.05）。多因子偏相关分析显示,异养细菌和弧菌与DO、pH、COD、TP的相关关系均不显著（P〉0.05）。结果表明,调查的养殖池塘对虾生长良好,该养殖池塘是安全、基本健康的系统,水环境中细菌数量受养殖系统中生物、环境因子及人为因素的影响和制约。     

冬季菲律宾蛤仔育苗系统几类主要细菌数量变化

试验结果表明:水中异养细菌为2.3×103-1.1×105cfu/m l,其变化趋势与温度变化一致;弧菌为5.0×103-6.6×103cfu/m l,其变化趋势与温度变化不一致,规律性不强。沉淀池泥中异养细菌为7.6×104-6.7×105cfu/g,弧菌为1.6×103-5.4×103cfu/g,反硝化细菌为2.5×102-3.2×104MPN/g,反硫化细菌为35-4.9×105MPN/g;温度高时,沉淀池泥中反硫化细菌占总异养菌比例最高,反硝化细菌次之,弧菌最小。从异养细菌的数量来看,沉淀池水质达到富营养化水平。因此,温度一旦升高,水中细菌会急剧增加,造成水质恶化,产生有毒的H2S、NO2-等物质,不利于菲律宾蛤仔的生长。     

甘蔗渣载体填料在海水曝气生物滤池中的应用

为研究甘蔗渣作为载体填料用于海水曝气生物滤池中的可行性,在海水曝气生物滤池中培养生物膜,并以此为基础构建海水养殖排放水处理系统。通过监测水体总氨氮(TAN)、亚硝酸盐氮(NO2--N)等水质指标浓度变化,水体游离细菌与载体附着细菌密度变化,评价甘蔗渣载体生物滤池的降解效果。结果显示,以甘蔗渣为载体的生物滤池挂膜所需时间为26 d,挂膜完成后甘蔗渣附着可培养总菌和芽孢杆菌密度分别为3×108cfu/g和7.8×107cfu/g。在处理养殖水体时,生物滤池中水体氨氮和亚硝酸盐氮浓度分别控制在0.2 mg/L和0.05 mg/L以下,同时,水体中芽孢杆菌数量由3.3×103cfu/L增加至7×104cfu/L,弧菌数量由4.9×103cfu/L下降至3.1×101cfu/L。研究表明,以甘蔗渣为载体的海水曝气生物滤池能快速有效地完成挂膜,并在海水养殖排放水处理中取得较好效果。     

噬菌蛭弧菌对乌鳢养殖水质的影响

为了探讨噬菌蛭弧菌制剂净化水质和病害防治的效果,试验以0.75 mL/m2的用量向乌鳢养殖池泼洒浓度为1.0×108pfu/mL的噬菌蛭弧菌制剂,观察7 d内养殖池的pH、DO、NH3-N、NO2--N含量及弧菌总数等主要水质指标以及乌鳢死亡数目的变化。向乌鳢养殖池加入噬菌蛭弧菌后,试验组与对照组相比,NH3-N、NO2--N含量及弧菌总数明显减少(p<0.05),DO明显增大(p<0.05),但pH变化不明显(p>0.05);乌鳢死亡率也明显减少(p<0.05)。试验结果表明,以0.75 mL/m2的用量向乌鳢养殖池泼洒浓度1.0×108pfu/mL的噬菌蛭弧菌制剂,有利于提高DO含量及乌鳢存活率,降低NH3-N、NO2--N含量及弧菌总数。     

对虾养殖的曙光

本文综述了我国在虾病病原、病理及诊断方面的进展,例举了一些虾病防治方面的成功经验,并认为对虾养殖业的发展出现了曙光。     

中国对虾产业现状及相关研究综述

中国对虾产业在国际上具有重要地位,但近年来中国对虾出口形势面临从未有过的巨大挑战,因此,了解我国对虾产品、产业的现状,加大我国对虾产品与产业的研究,对我国对虾产业增强竞争能力和可持续发展具有一定意义。     

Effects of Feeding Diets Containing 34 or 38% Protein at Two Feeding Frequencies on Growth and Body Composition of Channel Catfish

Channel catfish, Ictalurus punctatus, fingerlings were stocked (13,585 fish/ha) in twelve 0.04-ha earthen ponds and fed to satiation with diets containing either 34 or 38% protein (79.1 or 88.8 mg protein/kcal), either once or twice daily for 170 days. Experimental diets with the proper levels of essential amino acids, vitamins, and minerals were formulated by a commercial feed mill. No significant differences (P < 0.05) in growth and body composition of channel catfish were found when analyzed by protein level, feeding frequency, or their interaction. Average individual fish weight at harvest was 461 g. Net production was 4,152 kg/ha. Percentage protein, fat, and ash in the waste (head, skin, viscera, and frame) were 41.5, 41.4, and 12.2%, respectively, while fillet had 65.7, 30.4, and 4.0%, respectively.     

海水和淡水养殖凡纳滨对虾呈味物质的比较分析

对使用同种饲料喂养的海水和淡水养殖凡纳滨对虾(Litopenaeusvannamei)进行了感官评价、一般成分和呈味物质分析。海水养殖对虾感官评价总体得分高于淡水养殖对虾,海水养殖对虾在鲜味、甜味上优于淡水养殖对虾,而淡水养殖对虾带有明显的土腥味(P<0.01)。海水养殖对虾的灰分高于淡水养殖对虾,粗蛋白、水分及有机酸含量两类对虾差异不大。通过分析氨基酸、核苷酸、甜菜碱和有机酸等呈味物质,发现主要是谷氨酸、AMP、IMP、甜菜碱这几种物质对两类对虾的口味差异起着重要作用,其他成分作用不明显。     

Biosecure Shrimp Feeds and Feeding Practices: Guidelines for Future Development

For the purposes of this paper, biosecure shrimp feeds and on‐farm feeding strategies refer to the “feed, whether live, fresh, or formulated, and the management of the feed on the farm, should not be an entry point of potential pathogens to the shrimp and/or to the culture system.” The paper reviews the different feeds commonly used for the production of farmed shrimp and discusses their potential risks from a disease perspective, including the use of live hatchery and nursery feeds, the use of live and/or fresh food organisms for the production of broodstock, and the use of dry formulated shrimp feeds for shrimp growout operations. In addition, the paper discusses the critical role played by feed‐processing techniques for the pasteurization and destruction of pathogens within shrimp feeds and the need for nutritionists to formulate feeds for optimal nutrition and health, and not just for optimal growth. The importance of the development and implementation of good on‐farm feed management practices by farmers is discussed, including the prohibition of the top‐dressing of pelleted feeds on farm by farmers with unapproved feed additives such as antibiotics. Finally, the paper discusses the responsibilities of farmers, feed manufacturers, and traders regarding the development and use of recommended biosecure shrimp feeds and feeding practices.     

Water quality and plankton densities in mixed shrimp-mangrove forestry farming systems in Vietnam

Water quality and plankton densities were monitored in shrimp ponds at 12 mixed shrimp‐mangrove forestry farms in Ca Mau province, southern Vietnam, to detail basic water chemistry and assess whether conditions are suitable for shrimp culture. In general, water quality was not optimal for shrimp culture. In particular, ponds were shallow (mean ± 1SE, 50.5 ± 2.8 cm), acidic (pH < 6.5), had high suspended solids (0.3 ± 0.03 g l^?1), low chlorophyll a/phytoplankton concentrations (0.2 ± 0.05 µg l^?1 and 8600 ± 800 cells l^?1 respectively) and low dissolved oxygen (DO) levels (3.7 ± 0.15 mg l^?1). Eight out of the 12 farms sampled had potentially acid sulphate soils (pH < 4.2). Salinity, DO and pH were highly variable over short time‐periods (hours); DO in particular was reduced to potentially lethal levels (1–2 mg l^?1). Seasonal variations in water chemistry and plankton communities (i.e. salinity, DO, phosphate, temperature, phytoplankton and zooplankton densities) appear to be driven by differences in rainfall patterns. The presence or absence of mangroves on internal pond levees (‘mixed’ versus ‘separate’ farms) and the source of pond water (rivers versus canals) were of lesser importance in determining water quality patterns and plankton biomass. Zooplankton and macrobenthos densities were sufficient to support the current (low) stocking densities of shrimp. However, natural food sources are not adequate to support increases in production by stocking hatchery reared post larvae. Increasing productivity by fertilization and/or supplemental feeding has the potential for adverse water quality and would require improvements to water management practices. Some practical strategies for improving water quality and plankton densities are outlined.     

Effects of ammonia on growth and molting of Litopenaeus vannamei postlarvae reared under two salinity levels

ABSTRACT

Litopenaeus vannamei postlarvae were exposed to 0, 6, 13, and 19 mg/L total ammonia nitrogen (TAN) treatments. After 45 days, shrimp weight and length were lowest under TAN concentrations of 13 and 19 mg/L (P ≤ 0.05). Maximum weight gain was observed in control and 6 mg/L treatments. Mortality was highest (80.55 ± 4.80%) under 19 mg/L reared in 35 ppt salinity. Average intermolt periods of PLs exposed to 0, 6, 13, and 19 mg/L TAN were 11.5 ± 0.7, 10.8 ± 1.3, 9.4 ± 1.0, and 8.7 ± 0.6 days under 35 ppt and 11.1 ± 0.5, 10.7 ± 0.6, 10.1 ± 0.5, and 9.5 ± 0.2 days under 45 ppt salinity. Although TAN increased postlarvae molting frequency, its negative effects on the shrimp growth and survival of PLs was directly linked to its concentration and exposure duration. Higher salinity reduces the effects of ammonia and increases the survival.     

Substituting fishmeal with mixtures of wheat,corn and soya bean meals in diets for the white leg shrimp,Litopenaeus vannamei (Boone): effect on production parameters and preliminary economic assessment

We analysed the effect on production and economic performance of juvenile Litopenaeus vannamei of isoproteic diets substituting fishmeal by 25%, 50%, 75% and 100% with mixtures of wheat, soya bean and cornmeals. In a laboratory trial, 10 juveniles m^?2 (1.1 ± 0.1 g) were reared in 60‐L plastic containers using a recirculation system for 90 days. Three replicates were used to test each diet. A commercial diet serving as a reference and the diet with the highest content of essential amino acids (50% substitution, 6.46 ± 1.1 g) produced significantly higher shrimp final weight (7.12 ± 0.9 g, P < 0.05). There were not significant differences in specific growth rate and mean survival (85.9 ± 0.2%, P > 0.05). In a pond trial, 10 shrimp m^?2 (1.08 ± 0.3 g) were cultivated in 1.5 m^?3 cages for 35 days, testing the diets in triplicate. Final weight was significantly higher (P < 0.05) when 100% substitution was used (10.89 ± 0.24 g), while survival did not differ significantly among diets (P > 0.05). The optimal level of substitution was estimated at 86.0%. Apparently, nutrients contained in the diets combined well with natural feed available in the pond, up to a point where 7.3% of fishmeal inclusion is recommended. An economic analysis showed that 100% substitution produced the best results. We conclude that mixtures of wheat, corn and soya meals are potential alternatives to replace fishmeal effectively in diets for L. vannamei.