长吻Wei的营养和饲料研究Ⅱ：温度对摄食,生长及饲料转化效率的影响

在室内流水条件下测定不同温度（１５℃、２０℃、２５℃和３０℃）对长吻Ｗｅｉ幼鱼摄食。生长及饲料转化效率的影响。结果表明：长吻Ｗｅｉ摄食与生长的起始温度为１５℃；适宜温度区为２０－３０℃；最适温度为２５℃左右。水温为１０℃时，长吻Ｗｅｉ基本不摄食。水温为１５－２５℃时，长吻Ｗｅｉ摄食率 、生长率随永温升高而显著增加，２５℃和３０℃组间差异不大。饲料转化效率随水温上升明显提高，但水温升至３０℃时，饲料     

长吻的营养和饲料研究Ⅱ温度对摄食、生长及饲料转化效率的影响

在室内流水条件下测定不同温度（１５℃、２０℃、２５℃和３０℃）对长吻幼鱼摄食，生长及饲料转化效率的影响。结果表明：长吻摄食与生长的起始温度为１５℃；适宜温度区为２０—３０℃；最适温度为２５℃左右。水温为１０℃时，长吻　基本不摄食，水温为１５—２５℃时，长吻摄食率、生长率随永温升高而显著增加，２５℃和３０℃组间差异不大。饲料转化效率随水温上升明显提高，但水温升至３０℃时，饲料转化效率有下降的趋势。长吻幼鱼日投饵量可根据经验公式：Ｃ＝０．１４８Ｔ￣（１．６２６）Ｗ￣（－０．５２１）计算。     

论我国鲟鱼产业发展方向

一、我国鲟鱼养殖的现状和存在的问题目前，各种规格鲟鱼养殖存塘量约在６００万～７００万尾（４０００吨左右），其各种类所占比例（重量）大致为：史氏鲟３５％，杂交鲟２５％，中华鲟２０％，西伯利亚鲟１０％，其他种类１０％。养殖的主要区域为广东、湖北、福建和江、浙、沪，其养殖量所占比例大致为：广东２５％，湖北２５％，福建２０％，江、浙、沪１５％，其他省市合计１５％。鲟鱼为亚冷水性鱼类，生长适宜温度为１５～２６℃，广东和福建尽管冬季的水温较为适宜，但是一般地表水水温超过２６℃长达３～５个月，因此该地区并非鲟…     

温度对条纹石鮨蛋白消化酶活性影响的初步研究

水温１５～２０℃时，条纹石鱼旨各消化器官的重量占鱼体重的百分比大小依次排列为比肝重＞比胃重＞比肠重，而在２５～３０℃时则排列为比胃重＞比肝重＞比肠重；水温１５～３０℃时，随着温度的上升，单位体重中酶蛋白所占的比例呈下降趋势；１５～２０℃时，消化道蛋白酶的活性随着水温的升高而显著增大，超过２０℃时，蛋白酶的活性又呈下降趋势；１５～２０℃时，各消化器官中蛋白酶的比活均上升９倍，２０～３０℃时，肝蛋白酶的比活继续增大，而胃及肠蛋白酶的比活则略有下降。     

加州鲈鱼人工繁殖技术

加州鲈鱼人工繁殖技术陈文龙（浙江省德清县水产局）加州钟属鲈形目、太阳鱼科，为淡水广温性种类。该鱼自然分布范围在北纬２５－５０°，西经７０—１２５°，生存水温１—３６℃，适宜水温１５—２５°。其适应性强，性情温驯，生长迅速且易捕捞，是经济价值高的名贵鱼...     

锚头鳋的测报与预报

锚头鳋是寄生在鱼体表上的一种水生昆生。其由头、胸、腹三部分组成。雄虫不侵害鱼体，营自由生活。雌虫以头部深深扎入鱼体肌内，吸取鱼体营养，胸、腹裸露在外。性成熟后，卵囊增大。产卵时身体呈半透明状，其内有一黑点。水温１３℃时开始繁育，生育期随水温变化而变化，１５～２０℃水温约３５天，２１～２５℃约２８天，３０℃以上只存活２０天，３３℃以上生活受抑制，２０～２５℃生命活动最旺盛。１２００１年测报锚头鳋以成虫寄生在鱼体或水下越冬。２００１年，我们将带有锚头鳋病的草鱼１００千克（其中草鱼３０千克，鲢鱼６５千…     

大黄鱼养殖中几种常见病的防治方法

本尼登虫病 ［病因］本尼登虫寄生而发病。 ［症状］本尼登虫常寄生在大黄鱼、黄鳍鲷、真 鲷、黑鲷、石斑鱼等海水鱼的体表各处，尤其是背部 的前半段较多。本尼登虫在鱼体上寄生时，鱼在水 中焦躁不安，不断狂游，在网或池壁上摩擦，虫体后 固着盘的大小钩将表皮撕破，体表受伤发炎，分泌大 量粘液，严重时贫血、消瘦、体表局部或大面积溃疡 或出现烂颌、烂尾等并发症。 ［治疗］ 方法一：用淡水浸浴，在水温１０—２０℃浸洗１５－ ２０分钟，水温２０—２５℃浸洗１０—１５分钟，水温２５℃ 以上浸洗５—１０分钟，此方法劳动强度大，操…     

山区流水养鱼技术要点

山区流水养鱼技术要点一、水质和鱼池的要求１．水质条件流水养鱼要求水质清新、无臭、无异味，无明显的油膜浮沫，水源充足，水中溶氧不得低于５毫克／升。一年中要有６个月以上的适宜水温，水温一般在２０—３０℃之间，不得低于１５℃。如水温过低，在流水池前增建一个...     

大菱鲆养殖实用技术

本文就大菱鲆养殖的基本技术、条件要求做简单介绍。 一、苗种购入：大菱鲆苗种购入时体长要在５ｃｍ以上，鱼体色泽正常，有活力，无病害、畸形。 二、水温：大菱鲆是冷水性鱼类，养殖适宜水温要求在１０℃－２０℃之间，１４℃-１７℃水温为快速生长阶段。 三、盐度：大菱鲆养殖的适宜盐度２０‰－３２‰之间，２５‰－３０‰最为合适。 四、水质：大菱鲆养殖要求水质无污染，抽取地下海水可直接入养殖池使用，用外海水要进行过滤、杀菌。 五、用水量：根据对大菱鲆的养殖经验，以流水养殖为好。每天换水量至少在５个循环以上，如果水量充…     

大菱鲆养殖实用技术要点

大菱鲆产自英国、法国等欧洲国家的大西洋北部海域，为底栖性鱼类。我国于１９９２年引进大菱鲆进行人工养殖，目前已在山东等地发展到一定规模。大菱鲆肉质鲜嫩，营养价值高，很受消费者欢迎，发展前景看好。现就大菱鲆养殖的基本技术、条件要求做简单介绍。１ 苗种购入 大菱鲆苗种购入时体长要在５ｃｍ以上，鱼体色泽正常，有活力，无病害、畸形。２ 水温 大菱鲆是冷水性鱼类，养殖适宜水温要求在１０～２０℃之间，１４～１７℃为快速生长水温。３盐度 大菱鲆养殖的适宜盐度２０～３２之间，２５～３０最为合适。４水质 大菱鲆养殖要求水…     

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.     

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.     

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.     

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.     

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.     

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).