筒柱藻对仿刺参稚参和幼参生长的影响

在五触手幼体、附板稚参和幼参阶段的养殖水体中添加筒柱藻液，探讨筒柱藻对刺参养殖水质及生长性能方面的影响。试验设1个对照组和5个筒柱藻不同添加密度组，每组3个平行，进行150天。结果表明，筒柱藻投喂密度为20亿个／m3组的稚参附板率及总成活率显著高于对照组（P〈0．05），且投喂此密度组对于早期幼参的特定生长率和表观消化率影响显著，投喂筒柱藻对幼参中后期的生长性能影响不大；投喂筒柱藻较小程度增加刺参养殖水体中的氨氮含量（P〉0．05），较大程度增大刺参养殖水体的亚硝态氮含量，但投喂筒柱藻各试验组水体均符合刺参养殖水质标准。因此，筒柱藻较适合附板稚参及幼参前期添加，且最适添加密度为20亿个／m3。     

添力口甘蔗潼和芽孢杆菌对凡纳滨对虾生长和养殖环境的影响

分别向凡纳滨对虾（Litopenaeus vannamei）养殖水体中添加芽孢杆菌（处理A）、芽孢杆菌＋粉碎甘蔗渣（处理B）、芽孢杆菌＋粉碎-蒸煮甘蔗渣（处理c），检测养殖环境中的氨氮、亚硝态氮和硝态氮含量、水体中总菌数、水体中絮团含量和对虾生长指标，评估添加甘蔗渣和芽孢杆菌对对虾生长及养殖环境的影响。60天的养殖结果表明，养殖前期处理组B、处理组c的氨氮（TAN）浓度显著低于处理组A（P〈0．05）；甘蔗渣和芽孢杆菌的添加能够提高水体中生物絮团含量，养殖10天以后，处理组B和处理组C的生物絮团含量分别维持在6-3～20 ml／L、8．3～30 ml／L，各时期都显著高于处理组A（维持在2．7～8.3 ml／L）（P〈0．05）；处理组B、处理组c收获时对虾平均体重分别为8．56±0．21 g、8．84±0．26 g，显著大于处理组A（7．66±0．40 g）（P〈0．05）。     

冷水鱼循环水养殖中的低温氨氮处理技术研究

为解决冷水鱼养殖过程中养殖水体中的氨氮累积问题，根据低温生物滤器及臭氧催化氧化处理氨氮的特点，设计了冷水鱼工厂化养殖氨氮处理系统并进行了试验。试验基于以臭氧氧化为主、低温生物处理为辅的处理工艺，试验鱼为虹鳟鱼，养殖密度为23 kg/m3，试验水体约为10 m3，试验周期为7 d。结果表明，该系统能够满足冷水鱼工厂化养殖过程中有关氨氮处理的水质指标要求，处理后的养殖池进水口的水质指标总氨氮≤0．18 mg/L，硝酸盐氮氮≤29．43 mg/L，亚硝酸盐氮氮≤0．1 mg/L；养殖水体氨氮浓度监测表明，臭氧在水中残留低于0．008 mg/L，符合养殖鱼类对水体臭氧浓度的安全要求。     

罗非鱼-鱼腥草共生系统中鱼菜不同配比对池塘水质及细菌群落结构的影响

为了解罗非鱼-鱼腥草共生系统中鱼草不同配比对池塘水质及细菌群落结构的影响,本文构建了相同池塘覆盖面积不同鱼腥草种植密度（350 g/m3、450 g/m3、600 g/m3和0 g/m3）（M1）和相同种植密度不同池塘覆盖面积占比（5%、10%、15%和0%）（M2）的两种养殖模式。通过在以上两种模式条件下,研究各组对罗非鱼养殖池塘水质以及水体和鱼体肠道微生物群落的影响,探讨了罗非鱼-鱼腥草池塘共生系统中鱼草的相对最佳搭配比例。结果表明,在M1实验模式下,不同密度组鱼腥草浮床均能显著改善养殖水体氨氮、亚硝氮、硝酸氮、总氮、总磷、磷酸盐等水质因子,且在三个月养殖周期内,初始种植密度为450 g/m3的鱼腥草浮床组与350 g/m3和600 g/m3实验组相比,效果相对更加稳定。16S rRNA V4区的高通量测序分析显示M1模式下各组鱼腥草均能显著优化鱼体肠道和水体的菌群结构,并增加菌群多样性,且养殖时间越长,优化效果越明显;相同月份下,实验组450 g/m3和350 g/m3（p > 0.05）比实验组600 g/m3优化效果相对更稳定（p< 0.05）;在不同月份下,环境变化对罗非鱼肠道及水体细菌多样性的影响大于鱼腥草浮床对养殖水体的影响。在M2实验模式中,各组鱼腥草浮床均能显著净化罗非鱼养殖池塘水质,其总氮、总磷、氨氮、亚硝氮、硝酸氮、磷酸盐等均呈曲线变化,总体分析来看,在该养殖周期内,鱼腥草覆盖面积为10%的实验组对养殖水体NH4+-N,NO3-N,TN,TP以及PO43-P等指标的净化效率要相对稳定于实验组5%和15%。高通量测序分析结果表明不同覆盖面积鱼腥草浮床均能增加养殖水体和鱼体肠道的细菌微生物多样性,相对而言,10%覆盖面积组的效果更稳定。此结果为完善罗非鱼-鱼腥草共生养殖模式的鱼草配比提供了数据支撑。     

凡纳滨对虾养殖土池中使用益生菌制剂效果分析

以凡纳滨对虾为研究对象,通过在养殖池中施用益生菌制剂,在露天土池中的使用量分别为0、0.3g/m3、0.45g/m3、0.6g/m3水体,研究了在凡纳滨对虾养殖水体中使用益生菌制剂对氨氮(NH+4-N)、亚硝酸盐氮(NO-2-N)、化学需氧量(COD)等水质指标的影响和对凡纳滨对虾成活率以及饲料系数的影响,目的是探讨益生菌制剂在凡纳滨对虾养殖池塘中的适宜使用量。     

多级分养策略对翘嘴鳜幼鱼生长及水质的影响

为了解早期多级分养对翘嘴鳜（ Siniperca chuatsi）的生长及水质影响，用网箱将翘嘴鳜幼鱼在不同培育密度（1000，1500，2000尾/m2）下进行连续三级筛选养殖试验。结果显示，各密度组鳜幼鱼的生长速度存在差异，随着养殖密度的增加，鱼体生长速度降低；存活率在中等密度（1500尾/m2）组最高；在鱼苗3 cm之后，水体氨氮含量显著性升高。结果表明，三级分养策略可以有效提高苗种规格整齐度；使存活率显著性提高。鱼种在幼鱼早期生长速度快，需注意此阶段的营养需求。     

添加红糖和芽胞杆菌对日本囊对虾室内集约化养殖水质的调控作用

在日本囊对虾Marsupenaeus japonicus室内集约化养殖水体中添加红糖和枯草芽胞杆菌及其强化发酵液,研究其对养殖水质及日本囊对虾生长与存活的影响。结果表明,处理组水体在14d时即可形成具生物絮团特征的絮状物,镜检显示,该絮状物包含细菌、单胞藻、原生动物和无定形碎屑。对照组水体中的无机氮总产生量为56.2g/m2,而处理组水体中的无机氮总产生量为4.13g/m2;与对照组相比,处理组水体的COD和活性磷酸盐含量显著提高;对照组日本囊对虾产量为0.55kg/m2,处理组产量为0.65kg/m2;每千克对虾耗用水量对照组为28t,处理组为3.4t。研究结果表明,在水体中添加红糖和枯草芽孢杆菌不失为一种有效的对虾集约化养殖的水质调控技术。     

芽孢杆菌对草鱼养殖水质的影响

为研究芽孢杆菌对草鱼养殖水质的影响,选取体重约45g的草鱼210尾,随机分为2组,每组设3个平行重复.对照组在水中不添加任何菌,处理组每隔7d分别向水中按照1×108 cfu/m3添加芽孢杆菌菌粉,二组均饲喂基础日粮.草鱼养殖水体水质测定结果表明:与对照组相比,第28天处理组氨氮含量比对照组下降29.17％(P＜0.05).亚硝酸盐氮含量无显著性差异且在0.39 mg/L以下.第14天时,处理组硝酸盐氮含量比对照组降低60.26％( P＜0.01),在第21天和第28天分别比对照组提高26.98％(P＜0.05)和67.85％(P＜0.01).处理组的总无机氮含量在21d内无显著差异,第28天时下降了15.39％(P＞0.05).养殖水体pH值维持在6.8～7.6,各组之间无显著差异.养殖水体中添加芽孢杆菌可降低氨氮含量,改善养殖水体水质.     

地衣芽孢杆菌De在优质草鱼养殖中的应用研究

运用综合对比分析法探讨了地衣芽孢杆菌Bacillus licheniformis De在优质草鱼（Ctenopharyngodon idellus）养殖中的应用效果，其评价指标分别为成活率、水体pH、透明度、溶解氧及水中氨氮、硝酸盐浓度等。结果表明，施用地衣芽孢杆菌De可在一定程度上使水体环境和养殖生产性能得到优化，提高养殖草鱼的成活率，显著降低水体透明度及水中氨氮、硝酸盐含量（P〈0．05），使水体pH、溶解氧有利于草鱼的生长。其中施菌组较对照组的成活率、水体pH、溶解氧分别提高了3．2％、3．9％、25．5％，而水体透明度、氨氮及亚硝氮浓度则分别降低了38．5％、74．6％、69．3％。     

添加光合细菌对糙海参幼苗培育阶段的影响研究

以受精后24h孵化出的糙海参（Holothuria scabra）耳状幼体为研究对象,探讨养殖水体不同量光合细菌对糙海参苗期生长、成活、消化道消化酶活性和养殖水体水质变化的影响。试验设4个处理,光合细菌（浓度为1×10^11cfu·mL^-1）添加量分别是0m L（组1,对照组）、50m L（组2）、100m L（组3）和150m L（组4）,每个处理设3个重复,每个重复放养4×10^4尾幼体于室内水泥池（5m×3 m×1.5m）中,试验周期为41 d。结果表明,添加光合细菌组的糙海参出苗体质量和成活率均显著高于对照组（P〈0.05）,而组3和组4的体质量和成活率又明显优于组2（P〈0.05）,组3和组4之间的差异不显著（P〉0.05）。添加光合细菌还能不同程度地影响糙海参苗体消化道蛋白酶、淀粉酶和纤维素酶的活性,试验组3种酶的活性均显著高于对照组（P〈0.05）,而组3和组4的蛋白酶活性和纤维素酶活性显著高于组2（P〈0.05）,淀粉酶活性在3个试验组之间无显著差异（P〉0.05）。在试验第10天后,各试验组氨氮（NH3-N）和亚硝酸盐含量显著低于对照组（P〈0.05）,在试验第20天后,各试验组化学需氧量（COD）的值显著低于对照组（P〈0.05）,而总磷（TP）的差异不大（P〉0.05）。表明光合细菌可以促进糙海参幼体的生长,提高消化酶活性和成活率,并改良育苗水体水质。     

Protein and amino acid composition from the mantle of juvenile O ctopus vulgaris exposed to prolonged starvation

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.     

美人鱼发光杆菌对凡纳滨对虾非特异性 免疫功能及抗病力的影响

在基础饲料中分别添加0.1%和1%美人鱼发光杆菌灭活菌、0.1%美人鱼发光杆菌活菌配制成3种免疫实验饲料,以基础饲料为空白对照组饲料,每组设3个平行样。对个体质量为(4.83±0.36)g的凡纳滨对虾进行为期20 d的饲养实验,分别在0、5、10、15和20d进行取样,以血清中的酚氧化酶(PO)、酸性磷酸酶(ACP)、碱性磷酸酶(AKP)、超氧化物歧化酶(SOD)和溶菌酶(UL)活性为免疫指标,探讨了美人鱼发光杆菌作为免疫制剂对凡纳滨对虾非特异性免疫效应的影响;在投喂免疫饲料后的第22天,按0.004 2 kg/kg体重的剂量,直接投喂对虾白斑综合征病毒(WSSV)病料,并记录累积死亡率。结果表明,美人鱼发光杆菌免疫实验组对凡纳滨对虾血清中PO、ACP、AKP、UL和SOD活性影响明显高于对照组,并且在饲料中添加美人鱼发光杆菌后,明显提高了对虾抵御WSSV感染的能力。其中0.1%美人鱼发光杆菌活菌实验组的抗病毒感染能力最强,WSSV感染14d内累计死亡率为63.3%±5.8%;而对照组为96.7%±3.3%。研究表明,美人鱼发光杆菌添加在对虾饲料中能提高凡纳滨对虾非特异性免疫水平,增强抵抗疾病的能力,将其作为对虾免疫增强剂具有良好的应用前景。     

Effects of Spirulina platensis as a feed additive on growth and coloration of blue dolphin cichlids (Cyrtocara moorii Boulunger, 1902)

This study was carried out to investigate the effects of replacing fish meal with dietary Spirulina as a feed supplement on the growth performance and coloration of blue dolphin cichlids (Cyrtocara moorii). Five isonitrogenous (47% crude protein) and isocaloric (17.36 kJ/g digestible energy) diets were for formulated to replace FM with 0, 5, 10, 15 and 20% Spirulina (designated as Control, SP5, SP10, SP15 and SP20 respectively) and fed to the fish (initial body weight, 3.15 ± 0.01 g). Fish were randomly distributed into fifteen 120 L aquariums (26.5 ± 1.00°C), 15 fish per aquarium. The diets were tested in triplicate for 12 weeks. Experimental groups were fed twice daily (09:00 and 17:00) by hand to satiation. At the end of the feeding trial, significantly (p < 0.05) higher weight gain (WG), specific growth rate (SGR), protein efficiency ratio (PER) and lower feed conversion ratio (FCR) were observed in fish fed the SP10 diet when compared to the SP20 diet. There was no significant difference in these parameters between the other groups. The skin coloration of blue dolphin cichlid fed a diet containing Spirulina meal was enhanced. The best coloration was observed in the SP15 group. These impressions were objectively validated by chemical determinations of carotenoids extracted from fish skins and passed statistical tests of significance. The study findings show that Spirulina meal does not diminish growth rates except at very high levels.     

A Minchinia mercenariae‐like parasite infects cockles Cerastoderma edule in Galicia (NW Spain)

The cockle Cerastoderma edule fishery has traditionally been the most important shellfish species in terms of biomass in Galicia (NW Spain). In the course of a survey of the histopathological conditions affecting this species in the Ria of Arousa, a haplosporidan parasite that had not been observed in Galicia was detected in one of the most productive cockle beds of Galicia. Uni‐ and binucleate cells and multinucleate plasmodia were observed in the connective tissue mainly in the digestive area, gills and gonad. The parasite showed low prevalence, and it was not associated with abnormal cockle mortality. Molecular identification showed that this parasite was closely related to the haplosporidan Minchinia mercenariae that had been reported infecting hard clams Mercenaria mercenaria from the Atlantic coast of the United States. The molecular characterization of its SSU rDNA region allowed obtaining a fragment of 1,796 bp showing 98% homology with M. mercenariae parasite. Phylogenetic analysis supported this identification as this parasite was clustered in the same clade as M. mercenariae from the United States and other M. mercenariae‐like sequences from the UK, with bootstrap value of 99%. The occurrence of M. mercenariae‐like parasites infecting molluscs outside the United States is confirmed.     

Dietary thiamin and pyridoxine requirements of fingerling Indian major carp,Cirrhinus mrigala (Hamilton)

Two experiments were conducted to quantify the dietary thiamin (experiment I) and pyridoxine (experiment II) requirements of fingerling Cirrhinus mrigala for 16 weeks. In experiment I, dietary thiamin requirement was determined by feeding seven casein–gelatin‐based diets (400 g kg^?1 CP; 18.69 kJ g^?1 GE) with graded levels of thiamin (0, 0.5, 1, 2, 4, 8 and 16 mg kg^?1 diet) to triplicate groups of fish (6.15 ± 0.37 cm; 1.89 ± 0.12 g). Fish fed diet with 2 mg kg^?1 thiamin had highest specific growth rate (SGR), protein retention (PR), RNA/DNA ratio, haemoglobin (Hb), haematocrit (Hct), RBCs and best feed conversion ratio (FCR). However, highest liver thiamin concentration was recorded in fish fed 4 mg thiamin kg^?1 diet. Broken‐line analysis of SGR, PR and liver thiamin concentrations exhibited the thiamin requirement in the range of 1.79–3.34 mg kg^?1 diet (0.096–0.179 μg thiamin kJ^?1 gross energy). In experiment II, six casein–gelatin‐based diets (400 g kg^?1 CP; 18.69 kJ g^?1 GE) containing graded levels of pyridoxine (0, 2, 4, 6, 8 and 10 mg kg^?1 diet) were fed to triplicate groups of fish (6.35 ± 0.37 cm; 1.97 ± 0.12 g). Fish fed diet containing 6 mg kg^?1 pyridoxine showed best SGR, FCR, PR, RNA/DNA ratio, Hb, Hct and RBCs, whereas maximum liver pyridoxine concentration was recorded in fish fed 8 mg kg^?1 dietary pyridoxine. Broken‐line analysis of SGR, PR and liver pyridoxine concentrations reflected the pyridoxine requirement from 5.63 to 8.61 mg kg^?1 diet. Data generated during this study would be useful in formulating thiamin‐ and pyridoxine‐balanced feeds for the intensive culture of this fish.     

Sea bream culture in Egypt; status, constraints and potential

Marine fish farming in Egypt began in 1976 with the culture of gilthead sea bream, (Sparus aurata) as this fish was notably adaptable to brackish and marine pond conditions. Today, marine fish and shrimp farms amount to about 19,000 ha, out of which 42% is already in production while the rest, i.e., 58% is still under construction. In 1997, cultured gilthead sea bream production of 2,250 tons made up 3% of the 75,000 tons total aquaculture catch. In polyculture, usually with the grey mullet and sea bass, gilthead sea bream contributed 440 kg ha^–1 to the total yield of 1,700 kg ha^–1 (26%) over a period of 16 months. For the same period, the yield of monoculture ponds averaged 100 kg ha^–1, while in marine cages, yields ranged from 4–10 kg m³. In 1996–1997, fry of 0.25–1 g and fingerlings 1–10 g with a total of 3 million, were collected from the wild and 1 million fry were produced in the three marine hatcheries out of the four existing ones. The development of sea bream culture in Egypt is now severely inhibited by the shortage of seeds and adequate feeds. Exports of both sea bream and sea bass, during 1994–1996 averaged 1,300 tons per year.     

Fertilization by refrigerator stored sperm of the Indian major carp, Labeo calbasu (Hamilton, 1822)

This study reports on the spermatological properties, and on the development of a protocol for refrigerator storage (4°C) of Labeo calbasu (Hamilton, 1822) sperm for artificial breeding. Volume, motility, concentration and pH of the freshly collected sperm were 2.21 ± 0.53 (μL g^?1 of fish weight) (mean ± SD), 95 ± 1 (%), 1.93 ± 0.44 × 10⁹ (cells mL^?1) and 7.56 ± 0.17 respectively. Sperm activation was evaluated at different osmolalities of NaCl solution, and motility ceased completely when osmolality of the extender was ≥287 mOsmol kg^?1. Sperm retained motility for 24, 72 and 108 h, after refrigerator storage when sperm were undiluted, suspended in Alsever's solution and suspended in Alsever's solution containing 5% methanol respectively. Fertilization rate of fresh eggs with sperm stored at 4°C in Alsever's solution and Alsever's solution containing 5% methanol was 77% and 60% with a hatching rate of 60% and 43% respectively. The fertilization and hatching success of the stored sperm suggests potential to use refrigeration for transporting genetic material to hatcheries for artificial breeding of L. calbasu in Bangladesh.     

A novel approach to denitrification processes in a zero-discharge recirculating system for small-scale urban aquaculture

This paper presents an innovative process to solve the nitrate build-up problem in recirculating aquaculture systems (RAS). The novel aspects of the process lie in a denitrification bioreactor system that uses solid cotton wool as the primary carbon source and a unique degassing chamber. In the latter, the water is physically stripped of dissolved gaseous O₂ (by means of a Venturi vacuum tube), and the subsequent denitrification becomes more efficient due to elimination of the problems of oxygen inhibition of denitrification and aerobic consumption of cotton wool. The cotton wool medium also serves as a physical barrier that traps organic particles, which, in turn, act as an additional carbon source for denitrification. Operation in the proposed system gives an extremely low C/N ratio of 0.82 g of cotton wool/g of nitrate N, which contributes to a significant reduction of biofilter volume. The additional advantage of using solid cotton wool as the carbon source is that it does not release organic residuals into the liquid to be recycled. Operation of the system over a long period consistently produced effluents with low nitrate levels (below 10 mg N/l), and there was only a very small need to replace system water. The overall treatment scheme, also incorporating an aerobic nitrification biofilter and a granular filtration device, produced water of excellent quality, i.e., with near-zero levels of nitrite and ammonia, a sufficiently high pH for aquaculture, and low turbidity. The proposed system thus provides a solution for sustainable small-scale, urban aquaculture operation with a very high recovery of water (over 99%) and minimal waste disposal.     

Effects of metomidate anaesthesia or transfer to pur sea water on plasma parameters in ammonia-exposed Atlantic salmon (Salmo salar L) in sea water

Atlantic salmon (Salmo salar L) postsmolts weighing 150 ± 53 g were exposed to 14–15 mg l^–1 TA-N (total ammonia-N) in sea water in 1 m³ tanks for 24h. Blood samples were then taken A) immediately after the fish were netted from the exposure tanks and stunned by a blow to the head; B) 2–20 min after the fish were transferred to 15 l of an anaesthetic solution of metomidate in ammonia-free sea water; or C) 2–20 min after the fish were transferred to 15 l of ammonia-free sea water. Plasma TA-N level was 18% lower in the anaesthetised fish compared to in the fish sampled directly from the exposure tanks (p 0.05), and accordingly 16% lower in the fish transferred to pure sea water although this difference was not significant (p = 0.07). Plasma glucose level was higher in the fish transferred to pure sea water than in the fish receiving the two other treatments (p 0.05), but plasma urea, osmolality, Na^{+, Cl–, Ca2+ or Mg2+} levels did not vary significantly between the different treatments. Plasma TA-N level increased with time in the fish in the metomidate solution (p 0.02).