尖吻蝮幼蛇开口率的影响因素研究

目的了解人工养殖的不同体重尖吻蝮初生幼蛇对不同种类、重量食物的选择性,分析影响尖吻蝮幼蛇开口率的因素。方法将刚孵化出的尖吻蝮幼蛇按体重抽样分组,分别投入棘胸蛙幼蛙、多疣壁虎和小白鼠进行饲喂,统计不同体重的幼蛇对不同食物的偏好性、幼蛇对不同特征食物的选择性以及不同食物的损耗率。结果尖吻蝮幼蛇总开口率达98.33%,不同食物的开口率有显著性差异;在不同食物的分组开口实验中,投喂幼蛙的幼蛇开口率达95.0%,投喂壁虎的幼蛇开口率达60.0%,投喂乳鼠的幼蛇开口率仅15.0%。不同初生体重的幼蛇投喂壁虎、乳鼠的开口率差异显著,而投喂幼蛙的开口率差异无显著性。结论初生体重对幼蛇的进食能力有显著影响,尖吻蝮幼蛇开口食物应以幼蛙为主,壁虎为辅。     

尖吻蝮人工养殖灌喂技术研究

目的探讨采用灌喂器人工灌喂尖吻蝮技术的可行性。方法采用湖南京湘源蛇类养殖有限公司自主研制的灌喂器人工灌喂尖吻蝮,观察记录随机抽取的30条尖吻蝮幼蛇及30条尖吻蝮成蛇在机器灌喂后每条幼蛇的体重数据,每3个月测量1次,观察12个月统计尖吻蝮的体重增长情况,并与常规灌喂方法饲养的尖吻蝮进行比较。结果灌喂器饲养的尖吻蝮幼蛇成活率为86.67%,平均体重达（482.39±40.19）g;灌喂器饲养的尖吻蝮成蛇成活率为96.67%,平均体重达（1346.13±117.51）g。而同期常规灌喂技术饲养的尖吻蝮幼蛇全部死亡,尖吻蝮成蛇成活率为76.67%,平均体重（878.56±82.39）g。结论人工灌喂器饲养的尖吻蝮幼蛇及成蛇的体重增长快速,成活率高,值得推广。     

大口黑鲈和尖吻鲈骨骼系统的比较研究

对大口黑鲈和尖吻鲈的骨骼系统进行了比较研究。结果表明 :从整体看 ,大口黑鲈的脑颅较宽 ,吻短钝 ,眼后头部短 ;尖吻鲈的脑颅狭窄 ,吻部尖长而突出 ,眼后头部较长。各部分的骨骼特征 :大口黑鲈脑颅的中筛骨、侧筛骨、额骨、上枕骨、上耳骨、翼耳骨和围眶骨等与尖吻鲈有明显的区别 ;大口黑鲈咽颅中的前颌骨、齿骨、中翼骨、鳃盖骨骼、角舌骨、尾舌骨、下咽骨等与尖吻鲈又有显著的差异 ;大口黑鲈附属骨骼中的肩带骨、腰带骨、脊椎骨等有很大的不同。这些差异和不同可作为科间或属间分类依据。     

食物种类对尖吻蝮幼蛇开口率的影响研究

目的观察投喂不同食物时尖吻蝮（Dienagkistrodon acutus）幼蛇的开口率,研究尖吻蝮幼蛇对食物的选择性,寻找最适宜的尖吻蝮幼蛇开口饵料;研究气味对尖吻蝮进食行为的影响,为人工配合饲料开发提供理论基础。方法将尖吻蝮幼蛇随机分组,在相同条件下对幼蛇进行饲养,分别使用泽蛙、幼体蟾蜍、SD大鼠的乳鼠、昆明种小鼠幼鼠、大麦虫、蚯蚓、中华蟋蟀、蟑螂对尖吻蝮幼蛇进行投喂,并统计开口率;在黑暗条件下投喂新鲜的死泽蛙和小鼠肉块,减少振感和食物与环境间温差对尖吻蝮的刺激,观察记录尖吻蝮的进食行为。结果尖吻蝮幼体开口率与食物种类有明显相关性,对蛙类和鼠类的开口率较高,而对昆虫类几乎无捕食。同时存在多种食物时尖吻蝮对食物有一定选择性,对运动较活跃和体温较高的食物选择性高。尖吻蝮可凭借气味寻找到食物并完成进食,对死食的进食率较活食低。结论 （1）泽蛙和幼鼠是尖吻蝮幼蛇的理想开口饵料;（2）尖吻蝮捕食过程中,除依赖视觉、震感、颊窝红外热感等感知食物外,还可通过气味来识别食物。     

稚幼鱼的营养与饲料研究进展

在水产养殖中,稚鱼的营养来源主要依赖于活饵料,还不能大规模地用人工饵料来饲养早期稚鱼,尤其是开口期的稚鱼。投喂人工饵料也只是在以活饵料饲养了一段时期以后或是人工饵料和活饵料混合投喂。然而生产活饵料的高昂代价、天气条件对活饵料生产量的影响以及活饵料营养价值的变化,给稚幼鱼的人工培育带来了极大不便和潜在威胁。Person Le Ruyer计算了以活饵料(主要是卤虫)饲养尖吻鲈(Dicentrarchus labrax)的费用,饲养稚鱼到45日龄时,生产活饵料的费用占总生产费用的79%,在前3个月,活饵料占了饲养费用的50%,而活饵料却只占所需饵料总干重的1.6%。因此,寻找合适大小、有吸引力和可消化的人工微粒饵料来替代活饵料饲养稚幼鱼就成为了当前各国营养学家们致力研究的热点。       

尖吻鲈寄生拟合片虫属一新种描述(单殖吸虫纲,鳞盘虫科)

描述了采自广东省阳江市海水网箱养殖尖吻鲈鳃上寄生的单殖吸虫鳞盘虫科Diplectanidae Bychowsky,1957、拟合片虫属Pseudorhabdosynochus Yamaguti,1958中的1新种,文中量度μm,模式标本保存于中山大学华南寄生生物研究中心.     

尼罗尖吻鲈和鳜鱼染色体组型分析及比较

采用PHA、秋水仙碱腹腔或背部肌肉注射,活体培养法,以前肾为材料,低渗-空气干燥法制片,进行染色体观察,运用Micromeasure version 3.3染色体分析软件和Photoshop 7.0软件首次分析了尼罗尖吻鲈的染色体数目和核型,并同鳜鱼染色体数目和核型进行了分析比较,对今后拟采取的杂交尝试提供理论基础。结果显示：尼罗尖吻鲈染色体众数为2n=48,核型公式为2m+4sm+12st+30t,染色体臂数（NF）为54;鳜鱼染色体众数为2n=48,核型公式为6sm+12st+30t,染色体臂数（NF）亦为54;两种鱼染色体短臂上均无随体,单臂染色体较多。分析表明尼罗尖吻鲈与鳜鱼杂交成功的可能性较大。     

尖吻蝮仔蛇的人工模拟生态养殖试验

目的通过建立一个适应于尖吻蝮仔蛇生长发育的稳定的多功能生态系统的人工模拟生态养殖蛇场,以最大限度地降低仔蛇的饲料成本,从而达到降低人工养殖尖吻蝮蛇的成本。方法选取一个室外围墙式养蛇场作为试验基地。设计为适应于蛇、蛙、昆虫、蚯蚓、小杂鱼等动物生长繁衍的人工模拟生态环境,建立一个稳定的多功能蛇场生态系统,以尖吻蝮蛇100条,在试验以前随机抽取10条测量其体重和体长,并以活体动物饲料喂养法和科学饲养管理法进行试验养殖,并在进入第一、第二次冬眠前均随机抽取10条蛇仔测其体重和体长。结果本次试验与本蛇场室内人工饲养尖吻蝮仔蛇相比,不仅在体重、体长和肥满度方面均相差不大,而且仔蛇的存活率还有所提高。结论表明该人工模拟生态养殖蛇场能够满足尖吻蝮仔蛇生长发育的需要,达到了预期的目的。     

鲈-蟹混养模式下不同饵料对大口黑鲈生长和肠道菌群的影响

为研究鲈-蟹混养模式下冰鲜鱼(HB)、配合饲料(HS)和混合投喂(HH)等3种饵料投喂对大口黑鲈(Micropterus salmoides)生长和肠道菌群影响,采用16S rRNA基因高通量测序技术,分析了不同饵料对大口黑鲈生长性能、肠道菌群结构和多样性的影响。结果表明,生长性能指标方面,配合饲料组试验鱼的末均重、体长和特定生长率均显著低于冰鲜鱼组和混合投喂组的(P<0.05),混合投喂组最后养成规格最大,生长速度也最快,但与冰鲜鱼组差异不显著(P>0.05)。多样性分析结果显示,配合饲料的投喂降低了大口黑鲈肠道菌群的丰富度和多样性。在肠道菌群结构方面,冰鲜鱼组的优势菌属主要为克雷伯氏菌属(Klebsiella)、分枝杆菌属(Mycobacterium)、罗姆布茨菌属(Romboutsia)及发光杆菌属(Photobacterium),配合饲料组优势菌属为罗姆布茨菌(Romboutsia)、克雷伯氏菌属(Klebsiella)、分枝杆菌属(Mycobacterium)及醋杆菌属(Cetobacterium),而混合投喂组优势菌属则是克雷伯氏菌属(Klebsiella)、分...     

基于生物能量学原理构建异育银鲫生长、饲料需求和污染排放模型

为构建鱼类生长、饲料需求和污染排放预测模型, 提高鱼类精准投喂管理水平, 通过收集大量文献中异育银鲫(Carassius auratus gibelio)生长数据(异育银鲫体重0.25—550 g), 运用特定增长率(SGR)、日增长率(DGC)、日均增重(ADG-Linear)、热积温系数(TGC)和校正后的热积温系数(Rev.TGC)等生长模型计算其生长速率, 并通过计算实际观测值和预测值最小残差和法选出最适生长模型。结果发现, 在用TGC模型计算其生长率时, 异育银鲫在其生长周期中含有3个异速生长点, 根据该点的位置, 可以将异育银鲫的生长周期分为3个阶段: 0.25—13.1 g (第一阶段)、13.1—172.8 g (第二阶段)、>172.8 g (第三阶段)。在这3个阶段中调整后的TGC模型比其他模型(SGR、DGC、ADG)可以更好地预测实际养殖中异育银鲫的生长性能。鱼类在不同的生长阶段对饲料的需求量由消化能决定, 通过计算鱼体储积能、基础代谢能、热增能以及尿液和鳃的代谢能, 可以估算异育银鲫的消化能, 从而确定其饲料需求量。经估算, 对于体重为0.25—506 g的异育银鲫, 每生产1 kg鱼, 其消化能需求量约为1.94×104 kJ。在模型验证时, 以粗蛋白分别为43%、37%、31%的饲料投喂不同生长阶段的异育银鲫, 并利用营养物质平衡法估计废物排放量。研究发现, 实测值与模型预测值显著相关。模型可以在异育银鲫实际养殖过程中, 有效预估某个生长阶段异育银鲫的体重、所需要的饲料量以及氮、磷污染物排放量, 有望为异育银鲫差异化上市、节省饲料成本、减少饲料浪费以及养殖场的污染评价提供有效的预判工具。     

A robust flow-cytometric protocol for assessing growth rate of hatchery-reared barramundi Lates calcarifer larvae

In this study, a flow-cytometric cell cycle analysis method to assess instantaneous growth rate of whole larvae of the Australian barramundi Lates calcarifer was developed and validated. High-resolution DNA measurements of either fresh, frozen or RNAlater-preserved larvae (gap0-gap1, G(0) -G(1), coefficient of variation (c.v.) < 3, 4 and 5%, respectively) enabled the deconvolution of the DNA histogram and assignment of the proportion of nuclei into cell cycle compartments G(0) -G(1), S (DNA synthesis) and G(2) -M (Gap2-Mitosis). This technique can be also used for individual fish tissues such as brain, liver, fin and muscle. For the first time, the combined proportion of replicating nuclei (into S and G(2) -M phases) of whole fish larvae and absolute growth rate in length (mm day(-1)) has been correlated in commercial aquaculture conditions. Fast growing L. calcarifer larvae had an overall hyperplasia advantage as indicated by a greater proportion of cells in the S+G(2) -M phase compared with slow growing larvae, which might explain the increasing differences in size during culture. In a fasting trial, larvae ceased growth while maintaining the constant initial rates of cell division throughout a 6 day period. For a highly fed fast growing control group, cell division rates significantly increased after day 4. Flow-cytometric cell cycle analysis of whole fish larvae may provide fish biologists and aquaculturists with a better understanding of how cell division rates influence early growth in natural and artificial environments.     

Methodology in the study of seabass (Lates calcarifer Bloch): nutritional requirements in Singapore

This paper describes the effort of the Marine Aquaculture Section of the Primary Production Department in Singapore and the Institut Francais de Recherche pour l'Exploitation de la Mer in developing adequate facilities for fish nutritional requirement studies in Singapore, and in introducing appropriate nutritional methodology so that results are reliable and accurate. One of the first achievements was the demonstration of homogeneous fish (tropical seabass, Lates calcarifer Bloch) growth response in a newly established tank system before any nutritional experiments were initiated. The application of statistical procedures that take into consideration the power of a test and number of replications required has allowed for more accurate interpretation of results. This can be seen in the results of the first nutritional requirement experiment on the optimal dietary protein level of the seabass at constant energy.     

Sulphur amino acid requirement of juvenile Asian sea bass Lates calcarifer

The dietary requirement of juvenile Asian sea bass Lates calcarifer Bloch for total sulphur amino acids was studied. Fish (average initial weight of 2.59 ± 0.08 g) were reared in twelve 500 L fibreglass tanks provided with flow-through seawater at 26°C and salinity of 31 p.p.t. for 12 weeks. They were fed semi-purified test diets containing 6.2, 7.2, 8.1, 9.0, 10.8, or 12.6 g methionine kg⁻¹ dry diet and a basal level of 3.1 g cystine kg⁻¹ dry diet. The mean crude protein of the diets (containing defatted Peruvian fishmeal, squid meal, soybean meal, and free amino acid mixture to simulate the pattern of hydrolysed sea bass protein) was 46.02%. The crude fat content of the diets was 10.51% from a 1 : 1 mixture of cod liver oil and soybean oil. Survival was 100% in all treatments. On the basis of the growth response, the total sulphur amino acid requirement of juvenile Asian sea bass was estimated to be 13.4 g kg⁻¹ dry diet (2.9% of protein). Fish fed low levels of l -methionine had significantly lower weight gains and feed efficiency ratios as well as slightly higher hepatosomatic indices. No nutritional deficiency signs were observed other than growth depression in fish fed on diets that were low in methionine. This information is valuable in further refinement of formulations of practical diets for the Asian sea bass.     

The food of barramundi, Lates calcarifer (Bloch), in coastal and inland waters of Van Diemen Gulf and the Gulf of Carpentaria, Australia

Examination of the diet of Lates calcarifer , based on 3684 specimens of 4–1200 mm total length (T.L.), from two localities in north Australia showed it is an opportunistic predator with an ontogenetic progression in its diet from microcrustacea to macrocrustacea to fish. The increasing importance of fish in the diet of L. calcarifer in salt water (up to 87% of food consumed) involved a dietary shift from feeding on bottom-dwelling forms to pelagic forms. There were few differences in the diet of L. calcarifer between the two localities. Cannibalism was rarely encountered in the Gulf of Carpentaria although it was significant (11–4% of the diet of L. calcarifer of 1001–1200 mm T.L.) in Van Diemen Gulf. A significant correlation between predator and prey length was found for Ariidae, Dorosomidae, Engraulidae, L. calcarifer , Mugilidae and Polynemidae. The maximum prey/predator length ratio observed was 0–61 for the dorosomid, Nematolosa erebi.     

An inexpensive tag for short-term studies in milkfish (Cbanos chanos Forsskal) and in seabass (Lates calcarifer Bloch)

An opercular tag for marking adult milkfish ( Chanos chanos Forsskal) and seabass ( Lates calcarifer Bloch) is described. High tag retention and relatively low mortality rates were observed in adult fish handled two to ten times during 14-to 60-day tests. The features and advantages of the tag for marking large-sized fish in short-term studies are discussed.

Zusammenfassung

Eine preiswerte Markierung für Kurzzeitstudien des Milchfisches (Chanos chanos Forsskal) und der Centropomidae (Lates calcarifer Bloch)
Eine Kiemendeckel-Markierung für adulte Milchfische (Chanos chanos Forsskal) und Centropomidae (Lates calcacifer Bloch) wird beschrieben. Sie zeichnet sich durch gute Haltbarkeit aus und verursacht relativ geringe Mortalität bei adulten Fischen, die in Versuchen von 14 bis 60 Tage Dauer 2-bis 10mal untersucht wurden. Die Eigenschaften und Vorteile dieser Markierung für große Fische in Kurzzeitstudien werden diskutiert.

Résumé

Un marquage économique pour des études de courte durée du chanidé (Chanos chanos Forsskal) et du centropomidé (Lates calcarifer Bloch)
Un marquage d'opercule pour les chanidés (Chanos chanos Forsskal) et les centropomidés (Lates calcarifer Bloch) adultes est décrit. Une bonne conservation et une mortalité relativement basse ont été observées chez des poissons adultes examinés 2 à 10 fois pendant des expériences d'une durée de 14 à 60 jours. Les caractéristiques et les avantages du marquage de poissons de grande taille pendant des expériences d'une courte durée sont discutés.     

Some aspects of biology and aquaculture potentials of <Emphasis Type="Italic">Tilapia guineensis</Emphasis> (dumeril) in Nigeria

The paper emphasizes on the several attempts made to raise the brackish water tilapia species, Tilapia guineensis both on an experimental and production basis by researchers and fish farmers in Nigeria. Besides, the aquaculture potentials of Tilapia guineensis have been reported by several authors. However, problems exist which are not found with the culture of other tilapia species. Even under most favourable conditions (e.g. the monosex culture of Tilapia guineensis), a poor growth rate and a mediocre feed conversion do not presage profitable aquaculture exploitation. The present review therefore throws light on areas of further research to enhance the growth performance of Tilapia guineensis with emphasis on fish larvae nutrition and first feeding (development of bio-encapsulated feed for larval fish based on nutritionally enriched nematodes and Calanoid copepods), digestibibilty of the feed ingredients, elucidation of the dietary protein requirements, improved culture technique through the use of the Recirculating Aquaculture Systems and the adoption of the most recent technology (The YY Male technology) that produces Genetically Male Tilapia through genetic manipulation. Specific recommended areas for further research are also proffered.     

Assessment of growth characteristics,the survival rate and body composition of Asian sea bass Lates calcarifer (Bloch, 1790) under different feeding rates in closed aquaculture system

One of the essential factors to be addressed in the development of aquaculture is the feeding regime. This study was investigated to assess the effects of feeding rate on growth performance, feed utilization, chemical body composition survival rate, cannibalism and morphological indices of Asian Seabass, Lates calcarifer. Intended for the trial, one hundred forty sea bass individuals with an average weight 5.47 ± 0.11 g were randomly distributed in 4 concrete tanks (914 cm × 183 cm 122 cm) each; length × width × depth) and volume 18,399 L, for total 68 days. The fishes were fed with a pelleted diet containing 46% crude protein for different feeding groups designated as (T1, T2, T3 and T4). The feed was supplied with a rate of (T1) 3%, (T2) 4%, (T3) 6%, and (T4) 9% of fish biomass per day and feeding frequency were maintained three times per day to all the groups. At the end of the trial water physicochemical parameters was in acceptable range for Asian sea bass growth. The average daily weight gain (g), weight gain (g) and specific growth rate (%) was significantly higher (p < 0.05) in T3 and T4 as compared to T1 and T2 group. The poorest feed conversion ratio was recorded in T1 group with 3% biomass per day. The cannibalism rate was significantly (p < 0.05) higher in T1 (3%) compared to T3 and T4 treatment. The morphological indices, condition factors (CF), viscerosomatic index and hepatosomatic index (HSI) was significantly higher in T4 group as compared to other treatments. The protein, moisture and ash contents of the whole biomass of the Asian sea bass were not significantly influenced by feeding rate. The fat levels in the fish bodies increased significantly (p < 0.05) with increasing feeding ratio. The phenomenal regression indicates that 6.5% feeding rate per day is optimum for best growth performance, survival and minimum cannibalism rate for Asian sea bass in captivity. The outcome of the finding will help in promotion for not only the coastal aquaculture in Pakistan abut also elsewhere.