净化时间对微流水系统中鳙品质影响的研究

以商品规格的鳙为研究对象, 利用湖泊建立为流水系统, 研究净化时间对系统中鳙肌肉的营养成分、质构和持水特性及肌肉中滋味成分与挥发性气味物质的影响。结果表明, 在整个净化过程, 鳙肌肉中蛋白、脂肪含量呈显著下降, 灰分含量处理前后无显著差异; 鳙肌肉中挥发性盐基氮含量、羰基含量随净化时间延长而显著下降; 肌肉质构的硬度随净化时间延长而显著上升, 黏着性和咀嚼性优于净化初期, 弹性和回复性与初期显示差异不显著; 水溶性蛋白含量和游离氨基酸含量呈先上升后下降的趋势。综上所述, 微流水净化处理能够显著提升鳙肌肉品质, 改善鳙肌肉口感和风味。     

池塘循环水养殖对混养草鱼食用品质的影响

为探究养殖模式对草鱼(Ctenopharyngodon idellus)鱼肉品质的影响,实验对两种养殖模式下(传统池塘养殖和池塘循环水养殖)草鱼的食用品质进行了差异比较。结果表明,循环水养殖草鱼肌肉白度和弹性高于传统池塘养殖的草鱼,且其不饱和脂肪酸和必需氨基酸含量均显著高于传统池塘养殖;其中, n-3和n-6系列不饱和脂肪酸含量显著高于传统池塘养殖草鱼,是其1.2倍,使得草鱼的肌肉品质和营养品质更佳。此外,循环水养殖可降低草鱼中带有土腥味和青草味的己醛、庚醛和1-辛烯-3-醇等物质的含量,且鲜味核苷酸(IMP)含量高于传统池塘养殖草鱼,使得草鱼的风味更鲜美、浓厚。研究表明,循环水养殖草鱼的肌肉品质和营养特性均优于传统池塘养殖。     

短时微流水处理对池塘养殖鳙鱼肌肉滋味品质的影响

为探究短时微流水处理对池塘养殖鳙鱼(Aristichthys nobilis)肌肉滋味品质的影响, 采用微流水装置对池塘养殖鳙鱼进行处理, 研究处理时间(0、2d、4d、6d、8d和10d)对池塘养殖鳙鱼肌肉中基本营养成分、游离氨基酸、脂肪酸、核苷酸及其降解产物、甜菜碱含量和感官评分的影响, 以期为提升鳙鱼滋味品质提供新方法。结果表明: 随着微流水处理时间的延长, 鳙鱼肌肉中总游离氨基酸含量、甜味氨基酸含量、腺苷酸(Adenosine monophosphate, AMP)含量和甜菜碱含量呈现先增加后降低的趋势, 均在处理6d时含量最高, 较未处理组分别增加了17.74%、39.45%、28.00%和50.16%; 灰分和鲜味氨基酸含量呈现增加的趋势; 粗脂肪、总脂肪酸含量、饱和脂肪酸含量、单不饱和脂肪酸含量、多不饱和脂肪酸含量、苦味氨基酸含量、酸味氨基酸含量、次黄嘌呤核苷(Hypoxanthine riboside, HxR)和次黄嘌呤(Hypoxanthine, Hx)含量则逐渐降低; 粗蛋白含量在处理过程中无显著变化。滋味分析仪(电子舌)和感官评分结果表明, 微流水处理显著提高了鳙鱼肌肉鲜味和甜味, 降低了其咸味、苦味和腥味, 且处理6d时鳙鱼肌肉的滋味、气味、质地和色泽感官评分最高。故短时微流水处理可显著提高鳙鱼的肌肉滋味品质, 不降低营养品质, 适宜的处理时间为6d。     

Evaluation of natural food for planktivorous fish in Lakes Phewa, Begnas, and Rupa in Pokhara Valley, Nepal

Six floating 4-m³ cages stocked with 40 silver carp per cage (three cages) and 40 bighead carp per cage (three cages) were placed in each of the three subtropical Lakes Phewa, Begnas, and Rupa. The fish were cultured, without supplying artificial feed, from August 1994 to December 1995. Fish growth was positively correlated with water temperature, and a slight loss in weight occurred in January when water temperature fell below 16°C in all the lakes. Fish growth was better in Lake Phewa than in Lakes Begnas and Rupa, where food might not have been sufficient or of a quality to sustain fish growth. The fish fed on mostly indigestible phytoplankton, Microcystis aeruginosa in Lake Begnas and on Tabellaria fenestrata and Microcystis aeruginosa in Lake Rupa, which can lead to poor fish growth. The maximum growth rate of silver carp (5.8 g day⁻¹) and bighead carp (4.7 g day⁻¹) occurred in Lake Phewa when Ceratium hirundinella and Peridinium spp. were abundant from August through October. The food particles found in the gut were mostly similar in silver and bighead carp, though Cladocerans (Bosmina longirostris) were observed sparsely in the gut contents of bighead carp only. Received: May 21, 1999 / Accepted: September 28, 1999     

A second‐generation genetic linkage map for bighead carp (Aristichthys nobilis) based on microsatellite markers

Bighead carp (Aristichthys nobilis) is an important aquaculture fish worldwide. Genetic linkage maps for the species were previously reported, but map resolution remained to be improved. In this study, a second‐generation genetic linkage map was constructed for bighead carp through a pseudo‐testcross strategy using interspecific hybrids between bighead carp and silver carp. Of the 754 microsatellites genotyped in two interspecific mapping families (with 77 progenies for each family), 659 markers were assigned to 24 linkage groups, which were equal to the chromosome numbers of the haploid genome. The consensus map spanned 1917.3 cM covering 92.8% of the estimated bighead carp genome with an average marker interval of 2.9 cM. The length of linkage groups ranged from 52.2 to 133.5 cM with an average of 79.9 cM. The number of markers per linkage group varied from 11 to 55 with an average of 27.5 per linkage group. Normality tests on interval distances of the map showed a non‐normal marker distribution; however, significant correlation was found between the length of linkage group and the number of markers below the 0.01 significance level (two‐tailed). The length of the female map was 1.12 times that of the male map, and the average recombination ratio of female to male was 1.10:1. Visual inspection showed that distorted markers gathered in some linkage groups and in certain regions of the male and female maps. This well‐defined genetic linkage map will provide a basic framework for further genome mapping of quantitative traits, comparative mapping and marker‐assisted breeding in bighead carp.     

Feeding at different plankton densities alters invasive bighead carp (<Emphasis Type="Italic">Hypophthalmichthys nobilis</Emphasis>) growth and zooplankton species composition

Invasive Asian carps Hypophthalmichthys spp. are an ecological threat to non-native aquatic ecosystems throughout the world, and are poised to enter the Laurentian Great Lakes. Little is known about how these filter-feeding planktivores grow and impact zooplankton communities in mesotrophic to oligotrophic systems like the Great Lakes. Our purpose was to determine how different plankton densities affect bighead carp H. nobilis biomass and how bighead carp affect zooplankton species composition. We conducted a 37-day indoor mesocosm experiment (volume = 678 l) with high and low plankton treatments (zooplankton dry mass ≈ 1,900 and 700 μg l⁻¹; chlorophyll a = 25 and 14 μg l⁻¹, respectively) in the presence and absence of juvenile bighead carp (mean = 5.0 g, 8.5 cm). Carp lost weight in the low plankton treatment and gained weight in the high plankton treatment, suggesting that food availability may be a limiting factor to bighead carp growth in regions of low plankton densities. In the presence of carp, zooplankton shifted from Daphnia to copepod dominance, while in the absence of carp, Daphnia remained dominant. Chydorids and ostracods increased in the presence of carp, but only in the low plankton treatment, suggesting that the impact of bighead carp on zooplankton species composition may vary with zooplankton density. Chlorophyll was higher in the absence of carp than in the presence. Chlorophyll and zooplankton densities in many Great Lakes ecosystems are substantially lower than our low treatment conditions, and thus our results suggest that Asian carp establishment in these regions may be unlikely. Handling editor: S. Declerck     

Lipid content and composition in common carp – optimization of n‐3 fatty acids in different pond production systems

This study examined whether the lipid composition of common carp muscle can be improved and become an important source of n‐3 highly unsaturated fatty acids (HUFA) in human nutrition. Carp from three pond production systems in South Bohemia were given access to plankton, plankton with the addition of cereals, or pellets containing rapeseed cake suggested to enhance lipid nutritional value. White muscle fatty acid composition was investigated and compared among treatments. Fish with no supplements were characterized by a high content of n‐3 HUFA, especially eicosapentaenoic (EPA) and docosahexaenoic acid (DHA). Fish supplemented with rapeseed pellets had a moderate n‐3 HUFA level, while those supplemented with cereals were characterized by a high oleic acid content and low level of n‐3 fatty acids. The pond plankton populations contained high proportions of n‐3 fatty acids, including EPA and DHA, with an n‐3/n‐6 ratio around three. In summary, the rapeseed‐based pellet resulted in a more polyunsaturated lipid composition of the fish flesh, also with regard to n‐3 fatty acids. The conclusion is that the novel rapeseed‐based supplement is beneficial to human health.     

不同养殖模式下三倍体虹鳟鱼肉品质差异的研究

以网箱(W)、工厂化循环水(G)和流水池塘(C)养殖4 kg左右的三倍体虹鳟为研究对象, 通过检测表观、肉质、气味及营养价值相关111个品质指标来评价不同养殖模式下三倍体虹鳟鱼肉品质的差异。结果表明, 在3种养殖模式下三倍体虹鳟鱼肉品质存在明显差异。其中, 网箱养殖三倍体虹鳟鱼肉色调角、硬度、内聚性、弹性、咀嚼性、汁液流失率和失水率均显著高于其他养殖模式(P<0.05), 而挥发性气味物质中1-庚醇、庚醛、辛醛、壬醛和气味活度总值显著低于其他养殖模式(P<0.05); 工厂化循环水养殖三倍体虹鳟肥满度和鱼肉的红色值、色度值、盐溶性蛋白含量、总脂肪酸含量和n-3脂肪酸含量显著高于其他养殖模式(P<0.05); 流水池塘养殖三倍体虹鳟肥满度、鱼肉的黄色值、色度值、水分、脂肪含量、n-3脂肪酸含量和多不饱和脂肪酸含量最低(P<0.05), 出肉率、黏附性、肌糖原含量及挥发性风味物质中1-辛烯-3-醇、2,3-辛二酮、戊醛、庚醛、辛醛、(E)-2-癸烯醛和气味活度总值最高(P<0.05)。总之, 三种养殖模式养殖的三倍体虹鳟品质各具特色: 网箱养殖三倍体虹鳟鱼肉质地坚实富有弹性, 挥发性风味物质含量较低; 工厂化循环水养殖三倍体虹鳟具有较红的肉色并富含不饱和脂肪酸; 流水池塘养殖三倍体虹鳟形体优美且出肉率相对较高, 挥发性风味物质含量丰富。     

Effect of nutrition on fatty acid profiles of riverine, lacustrine, and aquaculture-raised salmonids of pre-alpine habitats

We examined trophic positions and fatty acid concentrations of riverine, lacustrine, and aquaculture diet and fish in Austrian pre-alpine aquatic ecosystems. It was hypothesized that dietary fatty acid (FA) profiles largely influence the FA composition of the salmonids Salvelinus alpinus, Salmo trutta, and Oncorhynchus mykiss. We analyzed trophic positions using stable isotopes (δ¹⁵N) and tested for correlations with polyunsaturated fatty acid (PUFA) concentrations. Gut content analysis revealed benthos (rivers), pellets (aquaculture), and zooplankton (lakes) as the predominant diet source. Results of dorsal muscle tissues analysis showed that the omega-3 PUFA, docosahexaenoic acid (DHA; 22:6n − 3), was the mostly retained PUFA in all fish of all ecosystems, yet with the highest concentrations in S. alpinus from aquaculture (mean: 20 mg DHA/g dry weight). Moreover, we found that eicosapentaenoic acid (EPA; 20:5n − 3) in fish of natural habitats (rivers, lakes) was the second most abundant PUFA (3–5 mg/g DW), whereas aquaculture-raised fish had higher concentrations of the omega-6 linoleic acid (18:2n – 6; 9–11 mg/g DW) than EPA. In addition, PUFA patterns showed that higher omega-3/-6 ratios in aquacultures than in both riverine and lacustrine fish. Data of this pilot field study suggest that salmonids did not seem to directly adjust their PUFA to dietary PUFA profiles in either natural habitats or aquaculture and that some alterations of PUFA are plausible. Finally, we suggest that trophic positions of these freshwater salmonids do not predict PUFA concentrations in their dorsal muscle tissues.     

Seasonal variations in stable isotope ratios of two biomanipulation fishes and seston in a large pen culture in hypereutrophic Meiliang Bay, Lake Taihu

This paper reports on seasonal changes in stable carbon and nitrogen isotope ratios of seston and muscle tissue of silver carp and bighead carp during 2004 and 2005, focusing primarily on the carbon sources and trophic relationships among phytoplankton, zooplankton and silver carp and bighead carp in a large fish pen of Meiliang Bay (Lake Taihu, China). δ¹³C showed a minimal value in March 2005 and a maximal value in August 2005 in seston both inside and outside the pen, whereas δ¹⁵N of seston showed the minimum in winter and the maximum during algal blooms. A positive correlation between δ¹³C of silver carp and that of seston suggested that temporal variation of δ¹³C in seston was preserved in fish via the food chain. The differences of δ¹³C among seston, zooplankton and muscle tissue of silver carp and bighead carp ranged only 0.2–1.7%, indicating that plankton production was the primary food source of filter-feeding fishes. According to a mass balance model, we estimated that the contributions of zooplankton to the diets of silver carp and bighead carp were 45.7% and 54.3%, respectively, based on the δ¹⁵N values of zooplankton and planktivorous fishes.     

四倍体异育银鲫新品种长丰鲫肌肉品质和营养成分分析

研究对长丰鲫、彭泽鲫、异育银鲫D系以及红鲫的肌肉品质和营养成分进行了对比分析。结果显示:肌纤维密度方面, 单位面积肌纤维密度长丰鲫最高[(184.2624.11) fiber/mm2], 其次为彭泽鲫[(149.7212.51)fiber/mm2]、异育银鲫D系[(134.4515.96) fiber/mm2]和红鲫[(119.8522.86) fiber/mm2]。粗蛋白含量、总氨基酸和呈味氨基酸方面, 长丰鲫、彭泽鲫和异育银鲫D系无明显区别。高度不饱和脂肪酸中(n3), 长丰鲫含量最高(24.2%), 依次为彭泽鲫(14.4%), 异育银鲫(11.3%)和红鲫(8.3%)。在高度不饱和脂肪酸中, 二十二碳六烯酸(DHA)长丰鲫含量最高(10.3%), 依次为红鲫(4.9%)、彭泽鲫(4.5%)和银鲫(2.9%); 花生四烯酸(AA)长丰鲫含量最高(8.3%), 依次为彭泽鲫(5.1%)、银鲫(3.8%)和红鲫(0.6%)。结果表明, 长丰鲫新品种在所检测的肌肉品质和营养成分指标方面, 优于彭泽鲫、异育银鲫D系和红鲫。     

Comparison of the trophic niches between two planktivorous fishes in two large lakes using stable isotope analysis

This paper studied the sources of food and the trophic levels of silver and bighead carps using stable isotopes (δ¹³C and δ¹⁵N) analysis in Lake Qiandao and Lake Taihu. The δ¹³C values of POM and phytoplankton indicated that Particulate Organic Matter (POM) is of terrestrial origin in LQ and phytoplankton origin in LT. The different signature of δ¹⁵N of phytoplankton and POM also showed the different extent of anthropogenic impacts on the two lakes, with higher impacts in LT than in LQ. In LQ the trophic levels of silver and bighead carps were significantly different (2.48 ± 0.19 and 2.66 ± 0.19, respectively), while in LT the difference was not significant (2.15 ± 1.54 and 2.36 ± 0.38, respectively). Using a mixing model, we found that silver and bighead carps consumed a major proportion on phytoplankton and/or POM in both lakes with higher contribution of phytoplankton in more eutrophic lake. Silver and bighead carps had clear differentiation in food resources with silver carp more on POM and bighead more on zooplankton in deep and mesotrophic lakes. Contrary to this, both carps fed primarily on phytoplankton (and POM) and may have more niche overlaps in shallow and eutrophic lakes.     

Food assimilation and filtering rate of bighead carp kept in cages

Bighead carp, Aristichthys nobilis Rich., dry weight food assimilation rates ranged from 37 to 49% (average 43%). The filtration rate ranged from 185 to 256 ml h^–1 g^–1 and was higher in larger fish. Bighead carp filtered Chlorella vulgaris (6 ± 0.4 µ diam) inefficiently (0.1 %), but the efficiency increased to 13 % for the larger Scenedesmus sp. (12 ± 1.7 µ diam). Fish kept in cages were forced to filter-feed, whereas fish kept free in the same pond were opportunistic plankton and bottom feeders. Free fish grew faster.     

池塘养殖匙吻鲟与鳙胃肠道饵料生物的比较

通过对同一试验池中匙吻鲟（Polyodon spathala）和鳙（Aristichthys nobilis）胃肠道内含物的连续3次分析,揭示他们滤食的天然饵料生物组成及差异。首先根据物种鉴定结果对2种鱼的胃肠道内饵料生物组成进行了UPGMA聚类分析,结果显示:相同采样时间同一池塘内2种鱼饵料生物组成存在差异,分别聚为不同的分枝;分析匙吻鲟和鳙胃肠道内饵料生物种类时还发现不同采样时间前者枝角类和桡足类种类数均多于后者。同时对2种鱼胃肠道内各饵料生物的生物量进行分析,结果显示:当大型饵料生物充足时,枝角类和桡足类的生物量在2种鱼胃肠道内没有显著差异（P0.05）;当大型饵料生物减少时,匙吻鲟摄食强度减小,但其枝角类和桡足类的生物量仍显著较大（P0.05）;当大型饵料生物消失后,轮虫生物量在匙吻鲟胃肠道内显著增加 （P0.05）;相比较,鳙在各采样期则主要滤食较小型的浮游动物和浮游植物。另外,当动物性饵料减少后,匙吻鲟和鳙均通过大量滤食植物絮团来补充能量。综上,同一试验池养殖的匙吻鲟和鳙存在摄食竞争压力,该压力的大小与环境中大型饵料生物的丰富度密切相关。       

Common carp (<Emphasis Type="Italic">Cyprinus carpio</Emphasis> L.) alters its feeding niche in response to changing food resources: direct observations in simulated ponds

We used customized fish tanks as model fish ponds to observe grazing, swimming, and conspecific social behavior of common carp (Cyprinus carpio) under variable food-resource conditions to assess alterations in feeding niche. Different food and feeding situations were created by using only pond water or pond water plus pond bottom sediment or pond water plus pond bottom sediment and artificial feeding. All tanks were fertilized twice, prior to stocking and 2 weeks later after starting the experiment to stimulate natural food production. Common carp preferred artificial feed over benthic macroinvertebrates, followed by zooplankton. Common carp did not prefer any group of phytoplankton in any treatment. Common carp was mainly benthic in habitat choice, feeding on benthic macroinvertebrates when only plankton and benthic macroinvertebrates were available in the system. In the absence of benthic macroinvertebrates, their feeding niche shifted from near the bottom of the tanks to the water column where they spent 85% of the total time and fed principally on zooplankton. Common carp readily switched to artificial feed when available, which led to better growth. Common carp preferred to graze individually. Behavioral observations of common carp in tanks yielded new information that assists our understanding of their ecological niche. This knowledge could be potentially used to further the development of common carp aquaculture.     

Alignment of microvascular units along skeletal muscle fibers of hamster retractor

Emerson, Geoffrey G., and Steven S. Segal. Alignment ofmicrovascular units along skeletal muscle fibers of hamster retractor.J. Appl. Physiol. 82(1): 42-48, 1997.When muscle fibers contract, blood flow requirements increasealong their entire length. However, the organization of capillaryperfusion along muscle fibers is unclear. The microvascular unit (MVU)is defined as a terminal arteriole and the group of capillaries itsupplies. We investigated whether neighboring MVUs along the fiber axis perfused the same group of muscle fibers by using the parallel-fibered retractor muscle. Hamsters were anesthetized and perfused with Microfilto visualize MVUs relative to muscle fibers. Fields of study, whichencompassed five to seven neighboring MVUs along a muscle fiber, werechosen from the interior of muscles and along muscle edges. On average,MVUs were 1 mm in length, 0.50 mm in width, and 0.1 mm deep; segmentsof ~30 fibers were contained in this tissue volume of 0.05 mm³ (20 MVUs/mg muscle). The totaldistance across muscle fibers encompassed by a pair of MVUs isdesignated "union" (U); the fraction of this distance common toboth MVUs is designated "intersection" (I). The ratio of I to Ufor the widths of neighboring MVUs provides an index of MVU alignmentalong muscle fibers (e.g., I/U = 1.0 indicates complete alignment,where the fibers perfused by one MVU are the same as those perfused bythe neighboring MVU). We found that I/U along muscle edges (0.71 ± 0.02) was greater (P < 0.05) thanthe ratio measured within muscles (0.66 ± 0.02). A model predicteda maximum I/U of 0.58 with random MVU alignment. Thus measured valueswere closer to random than to complete alignment. These findingsindicate that an increase in blood flow along muscle fibers requiresthe perfusion of many MVUs and imply that vasodilation is coordinatedamong the parent arterioles from which corresponding MVUsarise.

     

Design and Application of a Solar Mobile Pond Aquaculture Water Quality-Regulation Machine Based in Bream Pond Aquaculture

Bream pond aquaculture plays a very important role in China’s aquaculture industry and is the main source of aquatic products. To regulate and control pond water quality and sediment, a movable solar pond aquaculture water quality regulation machine (SMWM) was designed and used. This machine is solar-powered and moves on water, and its primary components are a solar power supply device, a sediment lifting device, a mechanism for walking on the water’s surface and a control system. The solar power supply device provides power for the machine, and the water walking mechanism drives the machine’s motion on the water. The sediment lifting device orbits the main section of the machine and affects a large area of the pond. Tests of the machine’s mechanical properties revealed that the minimum illumination necessary for the SMWM to function is 13,000 Lx and that its stable speed on the water is 0.02–0.03 m/s. For an illumination of 13,000–52,500 Lx, the sediment lifting device runs at 0.13–0.35 m/s, and its water delivery capacity is 110–208 m³/h. The sediment lifting device is able to fold away, and the angle of the suction chamber can be adjusted, making the machine work well in ponds at different water depths from 0.5 m to 2 m. The optimal distance from the sediment lifting device to the bottom of the pond is 10–15 cm. In addition, adjusting the length of the connecting rod and the direction of the traction rope allows the SMWM to work in a pond water area greater than 80%. The analysis of water quality in Wuchang bream (Parabramis pekinensis) and silver carp (Hypophthalmichthys molitrix) culture ponds using the SMWM resulted in decreased NH₃⁺–N and available phosphorus concentrations and increased TP concentrations. The TN content and the amount of available phosphorus in the sediment were reduced. In addition, the fish production showed that the SMWM enhanced the yields of Wuchang bream and silver carp by more than 30% and 24%, respectively. These results indicate that the SMWM may be suitable for Wuchang bream pond aquaculture in China and that it can be used in pond aquaculture for regulating and controlling water quality.     

老江河故道四大家鱼天然资源库研究

扼要介绍了老江河故道四大家鱼天然资源库的结构,并根据老江河故道水域生态系统的结构和功能特点,提出了四大家鱼的放养量应在重视种质质量的基础上,合理调控其放养结构和密度,此外文中还就保护和合理利用长江四大家鱼种质资源的有效途径以及维持老江河四大家鱼天然资源库健康运行的关键进行了分析探讨。     

Analysis of the growth performance,stress, profile of fatty acids and amino acids and cortisol in Tilapia (Oreochromis niloticus), cultured at high stocking density using in-pond raceway system

In-pond raceway system technology (IPRS) was introduced in Pakistan in 2019 as solution for sustainable aquaculture approach by effectively increasing production, reducing pollution and facilitating feed and pond management. Fingerlings of GIFT Tilapia (Oreochromis niloticus) (n = 16,500 in each raceway, initial weight = 32.00 ± 1.26 g) were stocked in June 2019 in two IPRS raceways (area of each raceway = 220 m³) for 171 days until harvested on November 30, 2019. Fingerlings stocked in traditional earthen ponds (area of each pond = 6167 m³) were studied as control (n = 3000 in each pond, initial weight = 32.00 ± 1.26 g). Average harvested biomass from raceways was 57.33 kg/m³ with an average daily weight gain per fish of 4.47 g per day. On the other hand, average harvested biomass from control ponds was 0.38 kg/m³ with an average daily weight gain per fish of 4.60 g per day. Average feed conversion ratio (FCR) in both raceways and control ponds was recorded as 1.25 and 1.24, respectively. Overall survival rate in both raceways and control ponds was above 99%. No sign of any disease was noted at any stage in both study groups. Crude protein and fats contents did not reduce in any raceway despite of high stocking density and sharp seasonal changes. Profile of essential and non-essential amino acids were found to be upto nutritional requirements of adult human. High levels of n-3 and n-6 fatty acids in fish collected from raceways as compared to those in traditional earthen pond show that muscle quality was not compromised due to high stocking density in small area. Return on investment excluding capital cost was 47.05 which implies that IPRS technology can be economically feasible with further modifications.     

新型湘云金鳙遗传多样性的RAPD及微卫星分析

湘云金鳙是本实验室经过近十年的工作选育出来的,该种鱼通体金红色,肉质鲜嫩,生长速度快,是一种很有价值的养殖鱼种和实验材料.随机选取12尾湘云金鳙(RBC)和12尾来自湘江流域的普通鳙鱼BC(作为对照)进行RAPD和微卫星分析.在优化RAPD检测条件基础上,从230个随机引物中筛选出来的45个扩增较好且多态性强的引物对这...