鱼类能量需要量研究进展

综述了鱼类能量需要量的研究进展。不同鱼类的基础代谢值差别不大，２０℃左右的３５～４５ｋｇ／ｋｇ＾－０．８．ｄ；鱼类维持能量需要低，为摄放总代谢能的１５％～２４％；鱼类合成Ｉｇ蛋白质和Ｉｇ脂肪代谢能需要分别主５３．９和４１．７ｋＪ。鱼类能量总需要可以用适宜能量浓度，单位体重和单位代谢体重能量需要表示，鱼类消化能需要在１３～１９ＭＪ／ｋｇ饵料，适宜能蛋比为３３．５～４６．１ＫＪＤＥ／ｇ蛋白质左右；单位     

主养鲤鱼种池搭配鲶鱼夏花的效益浅析

１材料与方法１．１试验池塘条件１９９５年为０．５３３ｈｍ２池塘，１９９６年为０．９６７ｈｍ２池塘。用漂白粉清塘（２０ｇ／ｍ３以上）３ｄ后，先施发酵鸡粪１２５ｋｇ／６６７ｍ２，然后加注老水１．２ｍ。在水温２０℃左右，７ｄ后待浮游动物较多时放入鲤鱼、鲢鱼...     

主施化肥的精养鱼池中叶绿素a及初级生产力的研究

对主施化肥的５种不同处理的精养鱼池中主要饲养期间的叶绿素ａ及初级生产量每月进行测定。结果表明：浮游植物现存量为１４８７３—２４２２６μｇｃｈｌａ／Ｌ，平均为１８７５０μｇｃｈｌａ／Ｌ，初级生产量为１４７９—２０００ｇＯ２／ｍ２·ｄ，平均为１７８１ｇＯ２／ｍ２·ｄ，鲢鳙鱼产力为３１０５ｋｇ／ｈａ·ｄ。初级生产量与叶绿素ａ呈极显著正相关。施肥后叶绿素ａ的增长量与施肥时叶绿素ａ的起始量有关。叶绿素ａ往往在施肥后２—３天（２５℃以上时）或３—４天（２０℃以下时）达到峰值，尔后逐渐下降，并于施肥后第４—６天或６—８天回复到施肥前水平，因此，施肥周期以４—６天或６—８天为宜。本文还对主施化肥鱼池的鲢鳙鱼产力、适宜的Ｎ／Ｐ比值及氯化铵的肥效进行了讨论     

莺河一库渔业潜力及开发对策

对莺河一库水质的调查分析和饵料生物的定量测定得出：该库属中营养型水库，浮游植物初级生产力平均２３．９６ｋｇＯ＿２／ｈａ·ｄ，其中鱼类生长期内初级生产力３２１．１６ｋｇＯ＿２／ｈａ·ｄ，净生产量２５．７３ｋｇＯ＿２／ｈａ·ｄ，净生产量之和为５４０３．３ｋｇＯ＿２／ｈａ，折合浮游植物鲜重为２８６３７．５ｋｇ／ｈａ；浮游植物、浮游动物和底栖动物的生物量分别为３．２ｍｇ／Ｌ、１．２６ｍｇ／Ｌ和０．８５ｇ／ｍ￣２，水库近期鱼产力为３６３．６ｋｇ／ｈａ，总产量２０．９４万ｋｇ。该库历年平均成鱼单产为８８．４ｋｇ／ｈａ，占估算鱼产力的２４．３％，水库的渔业潜力有待开发利用，因此，提出了今后合理开发水库渔业资源的对策。     

铬盐对鲤生长和饲料转化率的影响

以０．５ｍｇ／ｋｇ铬盐饲料饲喂１龄鲤６５ｄ和３月龄鲤３０ｄ，相对生长率分别提高１３．７９％和２０．６９％饲料转化率提高２１．８３％和２６．０％。表明铬盐有促进鱼类生长作用和提高饲料转化率的效应，而铬盐对鱼体营养成分的作用不明显。但铬盐对对高血糖症鱼的作用是低剂量各（２．５μｇ／ｋｇ体重）使血糖明显下降，高剂量（６０μｇ／ｋｇ体重）则使血糖明显升高；铬盐含量０．５ｍｇ／ｋｇ饲料使高血糖症鱼的血糖下降     

鳗鱼主要疾病之防治

十八、用药简介▲常用药品：序号药品作用用法用量停药期（ｄ）１鳗力强治赤鳍病、爱德华氏病、弧菌病、赤点病口服：１００ｇ／２０ｋｇ饲料，连用７ｄ。３０２百力强治赤鳍病、爱德华氏病、弧菌病、赤点病口服：１００ｇ／２０ｋｇ饲料，连用７ｄ。３０３鳗旺辅助治疗，...     

大龙口水库网箱养殖大口鲶试验

２只网箱共５０ｍ＾２，５月中旬购进３￣４ｃｍ规格大口鲶，长至１２￣２０ｃｍ时，入成鱼箱，饲养１２７ｄ，总产２０８５ｋｇ，合４１．７ｋｇ／ｈｍ＾２，尾重２．７５ｋｇ，成活率７５％。盈利１５１８２．７元，投入产出比１：１．５７。讨论分析了试验中存在的技术问题。     

红螯螯虾对温度耐受性的试验

测定了红螯螯虾幼虾和虾苗对温度的耐受性。３８℃时，虾苗仅能存活４ｄ，幼虾仅能存活３ｄ；３５℃１５ｄ后虾苗存活４０％，幼虾存活７０％。２５℃时，虾苗和幼虾的成活率分别为９３．３％和１００％。１５℃时１５ｄ后虾苗存活６３．３％，幼虾存活１００％。１０℃时虾苗８ｄ全部死亡，幼虾１５ｄ后存活９０％。幼虾８℃时，１５ｄ后存活２０％，５℃时４ｄ全部死亡。     

水库网箱养鲤越冬技术研究

水温２０℃时将越冬鲤放入越冬网箱，继续投饵。根据越简装期间水库撤水量，水温５－０７℃时将网箱平衡地沉入水下一定深度。越冬鲤密度为：鱼种６０－１２０ｋｇ／ｍ％＾２，成鱼１２０－２００ｋｇ／ｍ＾２。     

氨化小麦秸秆对绵羊的饲喂效果试验

本试验用２０只当地滩羊进行氨化小麦秸秆和普通小麦秸秆饲喂试验，结果表明，喂以２５０ｇ基础日粮时，自由采食氨化麦秸比自由采食普通麦秸平均日增重提高５６．６７ｇ，差异显著（Ｐ＜０．０５）；而喂以４００ｇ基础日粮时，自由采食氨化麦秸比自由采食普通麦秸平均日增重减少４．１７ｇ．差异不显著（Ｐ＞０．０５）。因此，对于体重３０ｋｇ左右的滩羊，用氨化麦秸作粗饲料时，每日每只补饲２５０ｇ混合精料（含消化能１５．９６ＭＪ／ｋｇ，粗蛋白质１０．８％）是有效可行的。     

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).