Oxygen Consumption and Ammonia Excretion of the American Eel Anguilla rostrata Fed Diets with Varying Protein Energy Ratios and Protein Levels

The effect of protein/energy ratio and protein level on utilization of protein and energy as indicated by oxygen consumption and ammonia production was investigated. When protein/energy ratio of the diet was optimum, there was no significant increase in ammonia production, indicating no increase in catabolism of protein for energy as protein levels increased. However, when the protein/ energy level was below optimum, there was a significant ( P < 0.05) increase in ammonia production as protein increased, indicating increased catabolism of protein for energy. However, there was no significant increase in oxygen consumption rate.     

Growth of Juvenile Green Sea Urchins,Strongylocentrotus droebachiensis,Fed Formulated Feeds with Varying Protein Levels Compared with a Macroalgal Diet and a Commercial Abalone Feed

The effects of varying protein and carbohydrate levels in prepared diets on the somatic growth of juvenile green sea urchins, Strongylocentrotus droebachiensis, were examined. Ten diets were tested on 600 hatchery reared urchins (mean start weight = 0.11 g) for 6 mo with three replicate groups per diet. Nine of the diets were prepared specifically for urchins and varied in protein (16–40% protein) and carbohydrate (29–49% carbohydrate) levels. The other two diets consisted of a commercially available abalone diet and the kelp, Saccharina latissima. Weight measurements were carried out at 6‐wk intervals, and at the end of the study urchins were individually weighed and a subsample from each treatment was analyzed for gonad weight and color. End weights after 6 mo ranged from 2.56 g for urchins fed the abalone diet to 6.11 g for urchins fed one of the prepared diets. Most of the prepared feeds outperformed kelp, and significant differences in growth were detected between some of the diets. In general, diets with lower protein levels (16–22% protein) and higher carbohydrate levels (>40% carbohydrate) produced the fastest growth. However, further diet refinement and/or use of finishing diets may be necessary to optimize gonad quality.     

海水土池育苗适口饵料生物培育技术

海水土池育苗可以利用池塘中天然饵料生物,因其具有成本低、收益好等特点而越来越受人们的欢迎。近几年来,河蟹土池育苗已兴起热潮,海水鱼类、贝类、虾蟹的土池育苗也已开始。但由于种种原因,土池育苗生产很不稳定,甚至失败,其中原因之一是育苗培育时饵料供应不足,营养不全面或是质量不好。浮游生物是多数鱼、贝、虾、蟹幼体的开口饵料、基础饵料,或是补充饵料,在育苗工作中起着重要的作用。搞好海水土池育苗,培育适口饵料生物是育苗的关键技术之一。在此介绍一些海水土池育苗中如何培育适口饵料生物的方法。     

在人工海水条件下，利用面包酵母培养褶皱臂尾轮虫（Brachionus plicatilis）的研究

在充气、以面包酵母为饵料、盐度为20的条件下,进行人工海水培养褶皱臂尾轮虫的实验。结果表明,不同人工海水中,用速溶海水晶配制成的海水和自然海水稀释的海水培养褶皱臂轮虫的效果明显地优于粗盐配制的;用速溶海水晶配制成的海水培养褶皱臂尾轮虫时,最大密度能达1710个／ml。不同营养强化剂中,绿色巴夫藻、扁藻以及胶囊肝油 蛋黄的效果较好。添加剂4ppm氯霉素时,培养褶皱臂尾轮虫的效果较好。     

Growth,Feed Conversion,and Nutrient Retention Efficiency of African Catfish,Clarias gariepinus, (Burchell) Fingerling Fed Diets with Varying Levels of Protein

Growth, feed conversion, and nutrient retention efficiencies of African catfish fingerling, Clarias gariepinus (5.22 ± .07 cm; 8.22 ± 0.03 g), fed diets with varying levels of protein were assessed by feeding seven casein/gelatin based isocaloric (17.62 kJ/g GE) experimental diets with graded levels of dietary protein (20%, 25%, 30%, 35%, 40%, 45%, and 50% of the diet) to triplicate groups of fish to apparent satiation for eight weeks. Effects of feeding these diets on live weight gain (LWG%), feed conversion ratio (FCR), protein efficiency ratio (PER), protein retention efficiency (PRE%), and energy retention efficiency (ERE%) were assessed. Maximum LWG% (867%), PER (2.01), highest PRE (32%), ERE (69%), best FCR (1.39), and maximum body protein were recorded in fish fed diet containing 35% protein. On the basis of the second-degree polynomial regression analysis of the above response variables, it is recommended that the inclusion of protein in the range of 34.4%–39.6% is optimum for maximizing growth potential, feed conversion, and nutrient retention in African catfish fingerling, Clarias gariepinus.     

海洋深层水在日本水产养殖中的应用概况

随着我国经济的飞速发展,人民生活水平的日益提高,人们对各种高档、稀有水产品的需求越来越多,为了满足这种需求,本文系统介绍日本海洋科技工作者利用海洋深层水养殖、培育高档鱼类方面所取得的部分成果,以供我国水产养殖科技工作者借鉴。     

Growth of Tilapia aurea in Seawater Cages

Fingerling Tilapia aurea were reared for 90 days in three 1.0 m³ floating cages in seawater (36 ppt) at Lee Stocking Island, Bahamas. Fish stocking density (100, 200 and 400 fish/m³) apparently did not affect growth rate but it appears salinity inhibited growth. Daily weight gain and specific growth rate (G) averaged 0.34 g/day and l.08%/day, respectively, for Tilapia aurea fingerlings. Infection of the Tilapia aurea by Bacillus sp. was associated with a significant number of mortalities. The relatively low growth rate and the high incidence of disease and mortality of Tilapita aures in seawater indicate that it may not be a good candidate for cage culture in full-strength seawater.     

海水越冬池冰下浮游生物群落结构特征的研究

为了解海水越冬池浮游生物群落结构特征,对四口海水越冬池的主要理化因子及浮游生物状况进行了监测。共鉴定出浮游植物27种(属),其中常见或形成优势种群者主要有蛋白核小球藻、椭圆小球藻、布氏棕鞭藻、小环藻、前沟藻、海洋原甲藻、多甲藻、裸甲藻、光甲藻以及绿裸藻10种(属)。浮游植物总平均生物量为149.96mg/L,绿藻门所占比例最多,达97.87%,其分布状况是中、下层明显大于表层。原生动物和轮虫种类较少,前者主要为侠盗虫,平均数量为2737.3个/L,后者主要是喜冷疣毛轮虫和喜盐疣毛轮虫,平均数量为583个/L,分布特点均表层明显多于中、下层。桡足类种类主要有指状许水蚤、细巧华哲水蚤和近亲真宽水蚤等,数量上呈典型的下多上少的梯形分布。研究结果表明:浮游生物种、量及其分布状况是影响海水越冬池溶氧状况的关键因素之一。     

海水围塘生态栽培坛紫菜

紫菜（Porphym sp）原是生长在潮间带的岩礁上,尤其是在风浪大、潮流畅通的海区生长良好。经过多年的人工栽培,紫菜已适应于在潮间带和浅海的养殖筏架的栽培。坛紫菜（Porphyra haitanensis）作为浙江、福建海区常见的栽培藻类和重要的食用经济海藻,有近40年栽培的历史。但潮间带可以用作栽培坛紫菜的空间越来越小,必须开拓新的栽培空间。在围塘栽培紫菜则是一种新开拓的栽培方法。     

海产品甲醛的形成及其对鱼肉品质的影响

海产品是我国重要的农副产品资源,其安全性逐渐受到关注。近年来,"甲醛问题"给海产品带来了巨大的的经济损失,也一直是全社会关注的热点。目前已证实,海产品在贮藏加工过程中,在内生酶作用下会生成甲醛。综述了海产品甲醛的存在形式、影响因素及对鱼肉品质的影响。     

微饵料在海水仔鱼中的应用研究进展

微饵料在成本、安全性、可获得性方面都优于活饵料,但微饵料并不能完全代替活饵料.仔鱼消化道发育不成熟,各种消化酶活性低,仔鱼对微饵料较低的摄食率、吸收率都限制了微饵料的使用.归纳了3种提高微饵料利用率的方法：活饵辅助微饵料,微饵料中添加外源消化酶,用水解蛋白源代替部分完整蛋白.3种方法在一些仔鱼中取得了一定的效果,但是对于不同品种的仔鱼效果不稳定,还需进一步改进.     

家用型水族箱养殖海水观赏鱼技术

海水观赏鱼以其怪异的体型、鲜艳的色彩,深受观赏鱼爱好者的青昧。家庭及办公场所海水观赏鱼饲养者常因养殖技术缺乏、经验不足而导致饲养失败。笔者结合自身养殖经验对水族箱的设置、观赏鱼品种的选择、水质指标的控制、饵料投喂及病害防治方面进行了分析与探讨,为家用型水族箱饲养海水观赏鱼提供技术支持。     

小尺度网箱缆绳张力在波浪中的变化特性

海水养殖网箱系统主要包括网箱框架、网衣和锚泊系统.其中锚泊系统是网箱系统安全的重要保证之一,而锚泊系统设计的核心问题是系泊力,即缆绳张力问题.为了保证受风浪冲击的网箱锚泊安全,必须对锚泊的动力负荷进行分析研究.为此本研究设计了一种小尺度网箱进行试验,通过测量不同波长、波高的波浪中网箱的缆绳张力、以及波浪通过网箱前后时的平均波高及波长,对网箱缆绳张力随波长、波高的变化进行分析和研究.结果表明,波浪中缆绳张力最大张力随波高的增加而增加,且随着波浪周期的增加张力增加的趋势随波高变缓,而波浪的波长和网箱框架的边长一致时,波浪单位截面积内的能量损失率达到最大值.     

Riboflavin Requirement of Fingerling Red Hybrid Tilapia Grown in Seawater

Red hybrid tilapia Oreochromis mossambicus × O. niloticus fingerlings were fed diets containing 0, 2.5, 5.0, 10.0, 20.0 and 40.0 mg/kg, and 0, 2.5, 5.0, 7.5, 10.0 and 20.0 mg/kg of riboflavin in separate 8 and 12 wk feeding studies, respectively. The dietary riboflavin level required to provide maximum growth and survival, and prevent deficiency symptoms in red hybrid tilapia fingerlings was found to be approximately 5 mg/kg of diet. In both trials, fish fed the diet devoid of supplemental riboflavin exhibited anorexia, reduced growth and nervous symptoms after 4–6 wk. Mortality began to occur after the sixth week. None of these abnormalities were observed during the first 6 wk in fish fed the riboflavin supplemented diets. However, by the seventh week, fish fed the diet supplemented with 2.5 mg/kg of riboflavin showed reduced appetite and growth rate. In both experiments, short body dwarfism was observed during week 8 for fish fed the diet without riboflavin supplementation. In experiment 1, fish fed the riboflavin-deficient diet had lens cataracts at week 8. This deficiency sign was not observed in experiment 2. Histological studies of liver, kidney, spleen, lateral muscle, gill and gastrointestinal tract revealed no major histopathological changes.     

聚乳酸/淀粉复合材料在海水中的降解性能

研究聚乳酸/淀粉复合材料在海水环境中历经8个月的可降解性能。对每个月取样样品的降解性能通过凝胶渗透色谱仪(GPC)、热重(TG)和力学性能进行评价,并对试样的形貌采用扫描电镜(SEM)进行观察。实验结果表明:随着在海水中降解时间的增加,样品分子量和分子量分布均逐渐减小,材料的热稳定性和冲击强度均逐渐下降,而材料的拉伸强度和断裂伸长率由于水分子的增塑作用均出现先减小后增大再减小的趋势。SEM照片显示随着降解时间的增加,材料内部逐渐出现空洞,结构变得松散。分析表明样品在海水中具有良好的降解性。     

Pyridoxine Requirement of Fingerling Red Hybrid Tilapia Grown in Seawater

Red hybrid tilapia (Oreochromis mossambicus × 0. niloticus) fingerlings were fed purified diets supplemented with pyridoxine hydrochloride at levels of 0, 3, 6, 12, 24, and 48 mg/kg diet for 10 weeks. Fish fed the diet without pyridoxine supplementation developed abnormal neurological signs, anorexia and convulsions followed by muscle spasms and lethargy after 9 days. These conditions progressed rapidly, and heavy mortality occurred at the end of week 2. Severe caudal fin erosion and mouth lesions were observed during the 3rd week. None of these symptoms were seen in fish fed pyridoxine-supplemented diets. At the end of 14 days, fish fed the pyridoxine-deficient diet had the lowest weight gain and poorest feed conversion (P < 0.01). Hematocrit values measured at the end of weeks 2, 6, and 10 were also consistently lower for fish on this treatment. Fish fed pyridoxine-supplemented diets for 10 weeks did not differ with regard to weight gain, feed conversion, and hematocrit. Histological study of various tissues revealed no apparent abnormalities in any of the treatment groups. It was concluded that 3 mg of pyridoxine/kg diet was sufficient for maximum growth, feed efficiency and survival, and prevention of various deficiency signs in red hybrid tilapia fingerlings grown in sea water.     

Comparison of Satiate and Restricted Feeding of Channel Catfish with Diets of Varying Protein Quality in Production Ponds

A 2 × 3 factorial experiment was conducted using satiate and restricted feeding with 32% crude protein diets containing low, medium, and high quality protein. Protein quality in the experimental diets was varied primarily by substituting peanut meal and cottonseed meal for soybean meal. Percentages of lysine, the first-limiting amino acid, were 1.14, 1.33, and 1.61 in the low, medium, and high quality protein diets respectively. Digestible energy concentration of the diets was 2.9 kcal/g. Channel catfish were grown from an average weight of 47 g to marketable size over a 15 wk period at a stocking density of 13,750 fish/ha in 400 m² earthen ponds. Each treatment was replicated in three ponds. Fish in the satiation group were fed as much as they would consume each day for the 15 wk experimental period. Fish in the restricted group were fed as much as they would consume until the daily feed allowance reached 65 kg/ha, which was reached at approximately week 5 of the experiment, and thereafter, there was no further increase in feed allowance. There was no significant interaction between feeding regimen and dietary protein quality for weight gain or feed conversion. Weight gain and feed efficiency under both satiation and restricted feeding increased linearly as protein quality increased. Protein quality had no influence on protein efficiency ratio (PER) under satiate feeding but had a positive effect on PER under restricted feeding. Protein quality had a positive linear effect on dressing percentage under restricted feeding, but in those fish fed to satiation, dressing percentage only increased between the low and high quality protein treatments. Protein quality had a negative linear effect on muscle fat but had no effect on visceral fat under satiate or restricted feeding. These results indicate that channel catfish are sensitive to protein quality differences in practical feeds at both satiate and restricted feeding rates, and that reduction in protein quality reduces dressing yield and increases muscle fat in food size fish.     

Response of Atlantic Croaker Fingerlings to Practical Diet Formulations with Varying Protein and Energy Contents

Atlantic croaker Micropogonias undulatus is a demersal marine species that is heavily utilized as both a bait and food fish, and which may have commercial culture potential as a bait species. This research sought to initiate the development of practical diet formulations for juvenile grow out and to evaluate the response of this species to controlled culture conditions. Eight practical diets were formulated to evaluate the effects of. 1) increasing lipid levels in a 45% protein diet; 2) dietary protein levels of 45, 40, 35 and 30%; and 3) progressive reduction in dietary energy content of diets with 30% protein. Each diet was offered to four replicate groups of fish having a mean initial weight of 3.8 g over a 7–wk growth trial. At the conclusion of the trial, final mean weights ranged from 17.0 g (410% weight gain) to 8.1 g (210% weight gain) with 100% survival for all dietary treatments. Weight gain and feed efficiency increased with protein content of the diet, with fish fed the 45% protein diet performing the best. Weight gain of fish maintained on the 45% protein diet decreased, but not significantly, as the lipid content of the diet was increased from 8 to 12 or 16%. Feed efficiencies for fish maintained on the diet containing 8% lipid were significantly higher than that of fish maintained on the diet containing 16% lipid. In low protein diets, the replacement of wheat starch with indigestible fiber did not significantly influence growth or feed utilization, indicating that high levels of digestible carbohydrate were not well utilized as an energy source by the fish. The observed results would indicate that growth is optimized on a high protein diet with moderate lipid levels.     

液质联用法检测海水中氯霉素的含量

应用液质联用仪测定海水中氯霉素的含量。水样经乙酸乙酯萃取、浓缩,以1 mL50%的甲醇-水溶液定容,采用液相色谱-三重四级杆串联质谱仪、多反应监测扫描模式（MRM）检测和氘代氯霉素内标法定量。海水中氯霉素检测方法的线性范围是0.10～10.0ng.mL-1,检出限为0.04μg.L-1,定量限为0.10μg.L-1,加标浓度在线性范围内时,回收率大于90%。试验证明：该方法比较稳定,适用于检测海水中氯霉素的含量。     

The Effects of Prophylactic Formalin Bath Treatment on Blood Glucose in the Giant Tiger Prawn Penaeus monodon

Abstract— Juvenile Penaeus monodon prawns were bathed in seawater-formaldehyde concentrations of 312, 625, and 1,250 ppm for up to 6 h. The tests were conducted at concentrations in excess of those previously published, in order to examine maximum tolerance levels to formaldehyde. Physiological stress was monitored by measurement of blood glucose levels. Under controlled laboratory conditions, 12 h food deprived juvenile prawns exposed to formaldehyde concentrations of 312 ppm did not exhibit signs of stress. However, bathing in formaldehyde concentrations of 625 and 1,250 ppm, caused significant increases ( P < 0.05) in blood glucose levels after 2 and 4 h, respectively. There were no mortalities in any treatment group. In contrast, juvenile prawns from grow-out ponds bathed in 625 ppm of formaldehyde immediately after 2.5 h of transport did not exhibit significant increases in blood glucose. This may be due to their nutritional status and these results are discussed. No significant change in blood glucose levels was observed in bilaterally eyestalk ablated prawns after exposure to 1,250 ppm formaldehyde. The increase of blood glucose due to formaldehyde treatment is presumably mediated by a stress response, which includes crustacean hyperglycemic hormone (CHH), and not a result of non-specific cell lysis and death.