绿鳍马面鲀规模化人工繁育技术

为满足工厂化养殖绿鳍马面鲀(Thamnaconus septentrionalis)对苗种的需求,利用体质量250 g以上人工养殖的绿鳍马面鲀作为亲本进行了规模化人工繁育试验。结果显示:采用沙蚕和牡蛎对亲鱼进行营养强化培育,培育水温20～22℃,经过20 d左右,亲鱼能自然产卵;将收集的受精卵均匀泼洒到育苗池中孵化,采用轮虫-丰年虫无节幼体-配合饲料的饵料系列,育苗成活率约为10%。试验结果表明:亲鱼培育前期投喂沙蚕,开始产卵后改投牡蛎,培育效果较好;要提高苗种成活率,繁育时饵料应选用高品质的丰年虫卵或及时换用鲜活桡足类。     

赤点石斑鱼人工育苗技术试验

正赤点石斑鱼俗称红斑,隶属于科、石斑鱼属,主要分布于中国南海、东海以及日本南部等地,因其肉质鲜嫩、营养丰富,深受消费者青睐,是水产养殖中一种经济价值高的品种。长期以来,赤点石斑鱼养殖苗种主要依靠天然采捕,因被过度捕捞,野生资源和养殖规模受到了很大的限制。本试验对亲本进行营养强化培育,并对苗种在开口阶段就加强营养,以提高育苗成活率,旨在为赤点石斑鱼实现工厂化养殖提供苗种来源。     

不同饵料对拟穴青蟹Scylla paramamosian后期幼体变态及成活率的影响

实验条件下研究了不同生物饵料种类对拟穴青蟹后期蚤状幼体生长发育的影响。结果表明：Z3~Z4阶段分别投喂初孵卤虫无节幼体、活体桡足类以及冰冻桡足类的3个实验组的培育成活率无显著差异,均在90%以上,但投喂卤虫无节幼体实验组的变态时间间隔缩短一天;Z4~Z5和Z5~M阶段,投喂活体桡足类实验组的培育成活率分别为95.72%和89.66%,Z3~M累计成活率达到80.18%,比投喂卤虫无节幼体实验组各发育阶段的培育成活率分别提高1.07%、6.09%和7.11%;比投喂冰冻桡足类实验组分别提高0.92%、5.14%和6.27%;3个实验组Z3~M所需天数,除投喂冰冻桡足类实验组为10 d外,其余两组均为9 d。实验结果可为丰富青蟹苗种培育的生物饵料种类和开展土池育苗生产提供有益的参考。     

石斑鱼神经坏死病毒传播途径阻断的初步研究

本文报告了斜带石斑鱼（Epinephelus coioides）苗种培育中亲鱼、卵、饵料等几个关键环节的病毒携带检测以及几种药物对病毒的消除效果的试验。用RT—PCR法检测斜带石斑鱼亲鱼的粪便、卵、仔鱼、稚鱼，饵料轮虫、桡足类中都有检出神经坏死病毒（nervous necrosis virus，NNV）。聚维酮碘5—10mg／L浸泡卵20min、浸泡轮虫和桡足类30min，盐酸吗啉胍3～5mg／L浸泡卵30min、浸泡轮虫和桡足类40min，聚维酮碘5mg／L＋盐酸吗啉胍3mg／L浸泡卵20min、浸泡轮虫和桡足类30min可有效灭活所携带的神经坏死病毒活性。     

海水桡足类的营养及在鱼、虾、蟹幼体培育中的应用

海水桡足类在海洋食物网和生态系统中具有重要的地位,是各种海洋经济鱼类和甲壳类的重要饵料,也是经济水产动物人工育苗阶段的优质活饵料源。研究海水桡足类营养和应用效果,对提高海水鱼、虾、蟹类幼体变态率、成活率、苗种质量和育苗成功率具有重要的意义。     

饵料系列对香鱼(Plecoglossus altivelis Temminck et Schlegel)人工育苗成活率、畸形率和白化率的影响

通过同一饵料系列(轮虫、卤虫无节幼体、桡足类、颗粒配合饲料)中不同的轮虫投喂时间,桡足类、颗粒配合饲料的比例,比较研究香鱼人工育苗的成活率、畸形率、白化率等育苗效果,以完善香鱼全人工批量育苗工艺.试验表明,在香鱼人工育苗仔稚鱼培育早期延长轮虫的投喂时间到15日龄可提高育苗的成活率及苗种规格;增加桡足类投喂量、减少颗粒配合饲料的投喂或采用研制全价的颗粒配合饲料有助于降低苗种的白化率;苗种的畸形与卵质有直接的关系,但同时与饵料、水质条件等因素有关.     

青石斑鱼人工繁育技术研究

平均体重为1.8kg的5－6龄育石斑鱼亲鱼，经强化培育，雄性亲鱼的促熟培育，性腺促熟，人工催产等措施，获受精卵320万粒，受精卵的卵化时间为26h，卵化率为80．7％，仔稚鱼的饵料系列为：牡蛎受精卵或担轮幼虫，轮虫，卤虫，桡足类；经41d培育，育出平均全长为3.79cm的幼鱼19万尾，培育成活率为7．3％，通过试验取得了一套可行的青石斑鱼人工繁育技术。     

鮸鱼苗种培育技术试验

经试验18尾亲鱼产卵5.3kg,受精卵经20h孵出,孵化率为63.9%;饵料系列为:轮虫、卤虫、桡足类;经50天培育,育出平均全长33mm幼鱼103万尾,培育成活率23.4%。     

斑点叉尾鲴苗种培育试验

斑点叉尾鲴苗种培育从卵黄苗培育开始,包括鱼苗培育和鱼种培育两个阶段.卵黄苗以枝角类为开口饵料,以后逐渐增加投喂罗氏沼虾仔虾料,鱼苗生长发育良好,成活率达90%以上.鱼种培育用出膜10-15天,全长2.0cm的鱼苗,按7742尾/亩,10551尾/亩,14981尾/亩三种密度放养,投喂粗蛋白含量32%以上的配合饲料,经99-133天的培育,分别获得43.7克/尾、18.8克/尾、10.9克/尾三种规格的鱼种.     

在轮虫培养中用敌百虫杀灭桡足类的试验

针对鱼、虾、蟹人工苗种生产中经常遇到的由于轮虫中混杂桡足类导致育苗失败的实际情况,探讨利用轮虫和桡足类对晶体敌百虫忍耐性的差异,在不影响轮虫生长、繁殖的情况下彻底清除桡足类的方法。结果表明:轮虫和桡足类对敌百虫的忍耐性有较大的差异,轮虫和桡足类的96h敌百虫安全浓度分别为2.0mg/L和0.2mg/L;致死浓度分别为3.0mg/L(96h)和0.4 mg/L(72h);在敌百虫添加浓度0.5~2.0mg/L条件下,敌百虫对轮虫繁殖率的影响随添加浓度加大而增加,但这一影响是可逆的,一般在2~3d后即可恢复正常。在苗种生产实际中,将敌百虫处理浓度定为1.0~1.5mg/L较为适宜。     

Broodstock diet with water and astaxanthin improve condition and egg output of brood fish and larval survival in Atlantic cod,Gadus morhua L.

Broodstock of Atlantic cod were fed with three diets; astaxanthin supplemented (100 ppm kg^?1) hydrated diet (30% water) (HWHAs), no additional astaxanthin supplemented (50 ppm kg^?1) hydrated diet (30% water) (HWLAs) and a control diet (50 ppm kg^?1 astaxanthin and 10% water). Throughout the spawning period, eggs were collected daily and fertilization success and proportion of embryos with normal cleavage were recorded. Larvae were reared using standard culture methods. Larval growth was recorded every 10 days and larval survival was recorded at 50 days post hatch. In general, broodstock fed with diets containing higher water content (HWHAs and HWLAs) and higher astaxanthin (HWHAs) had higher egg production and efficiency of egg output, lower egg incubation mortality and higher larval growth and survival. Broodstock fed with higher water content diets consumed less feed compared to control group. Also, broodstock fed with HWHAs and HWLAs recovered faster in terms of body condition than the control group. The egg bound mortality of female fish was significantly higher in control broodstock compared to broodstock fed with HWHAs and HWLAs. Broodstock fed with higher astaxanthin (HWHAs) had significantly higher fertilization success than other two groups however; no differences were found in proportion embryos with normal cleavage among different groups. Larval survival was significantly higher in HWHAs broodstock compared to other two groups. Our results showed that increased water content and astaxanthin levels in the diet could improve the condition and fecundity of Atlantic cod broodstock.     

Effect of Astaxanthin on the Pigmentation of Goldfish Carassius auratus

The optimal dosage of astaxanthin for goldfish Carassius auratus was determined by feeding a series of diets containing 0, 25, 50, 75, and 100 mg of astaxanthin/kg of diet for 4 wk. The pigmentation on fish skin was measured by visual assessment against a color chart and by counting chromatophores produced in the dermis layer of fish skin. Both criteria showed that 36–37 mg/kg astaxanthin was the optimal dosage to stimulate fish color. A 4-wk observation after this experiment demonstrated that fish color stimulated by dietary astaxanthin was stable in its intensity. Therefore feeding astaxanthin could be a suitable way for goldfish producers to stimulate color among fish grown in an algae-free environment. The survival rate of fish fed diets with astaxanthin was significantly higher than fish fed diets without astaxanthin. However, there was no significant effect of astaxanthin on fish weight gain.     

Effects of feeding frequency on the growth and body constituents of young red-spotted grouper, Epinephelus akaara

In order to obtain optimum feeding frequency in young red-spotted grouper, 25 000 fish averaging 4.7 cm in total length were divided into five groups in duplicate floating net-cages. Each group was reared with the same feeding ration to the fish weight but with different feeding frequencies: one, two, four, six, and eight times daily, respectively. High feeding frequencies resulted in high weight gain, high feed conversion efficiency, and high survival rate. The highest muscle mass and the highest levels of muscle protein were obtained at a feeding frequency of six times daily. While muscle lipid decreased with increasing feeding frequency, lipid levels of the liver and intraperitoneal fat body tended to be elevated by high feeding frequencies. Triglyceride accumulation in the whole body increased with increasing feeding frequency, but was lower in the group fed eight times daily than in the other groups.

Based on the above results, a feeding frequency between four and six times daily is suggested to be optimum for achieving optimum growth rates and lipid reserves in young red-spotted grouper.     

Growth and survival of Atlantic salmon, Salmo salar L. fed different dietary levels of astaxanthin. Juveniles

Atlantic salmon, Salmo salar L., juveniles, with a mean initial weight of 1.75 g, were fed casein-based purified diets which had been supplemented with different levels of astaxanthin for a 10-week period. The astaxanthin content of the diets ranged from 0 to 190 mg kg^?1 dry diet. The growth and survival of the juveniles were recorded throughout the experiment. The proximate composition, astaxanthin and vitamin A content were determined from whole-body samples at the start and termination of the experiment. The dietary treatment was found to affect growth significantly (P < 0.05). A reduction in the mean weight of the juveniles was observed in the groups fed the diets without astaxanthin supplementation. There was no difference in growth rate between the fish in the groups fed the diets containing 36 or 190 mg astaxanthin kg^?1 dry diet, whereas the fish in the group fed the diet containing 5.3 mg astaxanthin kg^?1 dry diet had a lower growth rate. There was a tendency to higher survival in the groups fed the diets containing astaxanthin when compared with the groups fed the non-supplemented diets. The moisture and ash contents were significantly lower and the lipid content was higher in the groups fed the astaxanthin-supplemented diets. The astaxanthin and the vitamin A concentrations in the fish were found to be dependent upon the dietary astaxanthin dose; the highest values were found in the fish fed the diet with the highest astaxanthin content. These results strongly indicate that astaxanthin functions as a provitamin A for juvenile Atlantic salmon. The body storage of vitamin A increased in the fish fed the diets containing astaxanthin. However, the increase was low in the fish fed the diet containing 5.3 mg astaxanthin kg^?1 dry diet.     

The optimal dietary protein level of large‐size grouper Epinephelus coioides

An 8‐week feeding trial was conducted to determine the requirement of protein for large‐size grouper Epinephelus coioides (initial body weight: 275.07 ± 1.56 g). Six iso‐lipidic (124 g/kg) diets were formulated containing graded levels of protein (350, 400, 450, 500, 550 and 600 g/kg). Grouper was hand‐fed twice daily to apparent satiation with triplicate. The results showed that significantly high weight gain, specific growth rate and significantly low feed conversion ratio were observed in fish fed 450 g/kg protein group. High‐protein level diets significantly increased protein content and significantly decreased lipid content of fish body and muscle. Total protein and cholesterol content in serum of 600 g/kg group were significantly higher than those of 350 g/kg group. However, serum glucose and triglyceride contents of fish fed low‐protein diets were significantly higher than those of fish fed high‐protein diets. Meanwhile, liver glutamic‐pyruvic transaminase and glutamic‐oxaloacetic transaminase in high‐protein diet groups were significantly higher than those of low‐protein diet groups. The intestinal protease activity in high‐protein diet groups was significantly higher that of low‐protein diet groups, but lipase and amylase showed opposite trend. With the increasing of dietary protein level, the activities of alkaline phosphatase, superoxide dismutase and lysozyme in liver of grouper increased significantly compared with 350 g/kg group, while the activities of acid phosphatase decreased significantly. With specific growth rate as the evaluation index, the optimum dietary protein level of large‐size grouper Epinephelus coioides was 438.39 g/kg by fitting the broken‐line regression analysis.     

凡纳滨对虾亲虾繁殖期间适宜投喂频率的研究

在饱食投喂条件下,选用鲜活饵料沙蚕(Nereis succinea)对凡纳滨对虾(Litopenaeus vannamei)亲虾进行营养强化培育60 d,通过比较不同的投喂频率2次/d(F2组)、3次/d(F3组)、4次/d(F4组)对亲虾摄食、生长、繁殖性能、虾体组成和肝胰腺的消化酶活力的影响,旨在探究亲虾繁殖期间营养强化的最适投喂频率。结果显示,随着投喂频率的增加,亲虾的日摄食量逐渐增大,F2组显著低于F4组(P0.05),但与F3组差异不显著(P0.05);亲虾的增重率和体长增长率呈先升高后降低的趋势,但无显著性差异(P0.05)。不同的投喂频率对各组亲虾的单次产卵量、相对产卵量、无节幼体I期个体数、无节幼体孵化率、蚤状幼体I期个体数、无节幼体变态率、性腺指数、初产时间和产卵间期均无显著影响(P0.05)。亲虾全虾主要体组成分水分、粗蛋白、粗脂肪、灰分含量也不受投喂频率增加的影响(P0.05);F2组的胰蛋白酶和脂肪酶活力显著低于F3、F4组(P0.05),而不同实验组的胃蛋白酶和淀粉酶活力无显著性差异(P0.05)。结合本研究的结果和生产实际情况,建议在饱食投喂条件下,凡纳滨对虾亲虾繁殖期间营养强化的适宜投喂频率为2次/d。     

Increasing survival and growth in larval leopard coral grouper (Plectropomus leopardus) using intensively cultured Parvocalanus crassirostris nauplii

Leopard coral grouper, Plectropomus leopardus are a heavily exploited, high-value fish commonly found in the Asian live reef food fish trade. In past decades, many attempts at the mass culture of various grouper species have been undertaken; however, their small mouth gape at first feed has resulted in very low survival when using traditional live feeds such as rotifers. The use of wild caught or extensively cultured copepods has yielded potentially promising increases in survival and growth, but overall survival to the juvenile stage remains low, making mass culture currently impractical. The current study sought to build on past developments in grouper culture and recent advancements in copepod culture technology by observing how growth and survival were influenced by the addition of intensively cultured copepods to the early diet of P. leopardus larvae. Six tanks of larvae, three replicates per treatment, were fed either eggs and nauplii of the calanoid copepod Parvocalanus crassirostris, at a starting density of 5 mL⁻¹, and the rotifer Brachionus rotundiformis, at a starting density of 10 mL⁻¹, or were fed only B. rotundiformis, at a density of 15 mL⁻¹, starting on the evening of 2 days post-hatch (dph) and continuing until 9 dph. After this initial period, all larvae were fed the same diet of rotifers, Artemia, and dry feed until the cessation of the trial at 21 dph. Larvae fed P. crassirostris in addition to rotifers had a significantly higher survival, 9.9 versus 0.5%, than those fed only rotifers. Growth was also significantly enhanced in larvae offered copepods. Larvae only fed rotifers were, on average, 1.5 mm shorter at 21 dph than those that had been fed copepods. More rapid development and the earlier onset of flexion were also noted in the larvae that were offered copepods. The use of intensively cultured copepods, in this study, increased survival tenfold over previous studies, with P. leopardus larvae fed wild-caught copepods. The application of intensively cultured copepods to the early diet of P. leopardus, along with future research to evaluate late-stage mortality issues, may facilitate commercial production of this species.     

Effect of Astaxanthin from Xanthophyllomyces dendrorhous on the Pigmentation of Goldfish, Carassius auratus

Two experiments were conducted to evaluate the addition of astaxanthin from red yeast, Xanthophyllomyces dendrorhous, in the diets of goldfish, Carassius auratus. The first was designed to investigate the distribution of pigments in different tissues of goldfish and the effect of astaxanthin in the diet. The carotenoid concentration of tissues was not homogenous. The content of pigments in fish caudal fin was the highest followed by those of scales and head. Flesh had the least carotenoid deposition. Fish fed the diet containing 60 mg/kg astaxanthin had increased concentration of pigment in its head (22.6%), scales (45.5%), flesh (31.0%), and fin (21.2%), compared to fish fed basal diet (P < 0.05). Sixty parts per million astaxanthin had no effect on the weight gain and survival rate. High‐performance liquid chromatography analysis showed astaxanthin in its esterified form in goldfish. The second experiment was aimed at determining the dietary level of astaxanthin that improved color of goldfish. Goldfish were fed the same diet supplemented with 0, 10, 20, 40, 60, and 80 mg yeast astaxanthin/kg for 60 d. The deposition of carotenoids in goldfish fed diets supplemented with astaxanthin increased significantly (P < 0.05) after 15 d of feeding compared to that of the fish fed the diet without astaxanthin, but the effect of dosage of astaxanthin in the diets on the color of goldfish was not completely evident until Day 60 (P < 0.05). During the period of 15–45 d, the deposition of pigments in fish did not increase significantly (P > 0.05) in any treatment with the exception of the diet with 40 mg yeast astaxanthin/kg.     

The Use of Natural Carotenoids and Growth Performance,Skin Pigmentation,and Immune Response in Fancy Carp (Cyprinus carpio)

Fancy carp were fed seven dietary treatments with natural pigment sources (tea, mulberry, cassava) at a specific rate to achieve a total carotenoid (TC) concentration in the diet of 25 mg/kg. Growth performance among treatments was not significantly different (p ≥ 0.05). TC and skin redness (a*) of fish fed tea leaves was higher than the other treatments (p ≤ 0.05). Fish fed with tea extract and cassava leaves had higher serum astaxanthin concentrations than the other groups (p ≤ 0.05). This group also retained serum astaxanthin and red color better than other groups two weeks post treatment (p ≤ 0.05). Phagocytic activity was significantly greater in fish fed carotenoid supplements compared with the control group (P ≤ 0.05). Therefore, dietary supplementation with 25 mg/kg tea leaves is sufficient to obtain good coloration in fancy carp as well as enhance immunity.     

Egg quality determinants in cod (Gadus morhua L.): egg performance and lipids in eggs from farmed and wild broodstock

Lipids and essential fatty acids, particularly the highly unsaturated fatty acids, 20:5n‐3 (eicosapentaenoic acid; EPA), 22:6n‐3 (docosahexaenoic acid; DHA) and 20:4n‐6 (arachidonic acid, AA) have been shown to be crucial determinants of marine fish reproduction directly affecting fecundity, egg quality, hatching success, larval malformation and pigmentation. In Atlantic cod (Gadus morhua L.) culture, eggs from farmed broodstock can have much lower fertilization and hatching rates than eggs from wild broodstock. The present study aimed to test the hypothesis that potential quality and performance differences between eggs from different cod broodstock would be reflected in differences in lipid and fatty acid composition. Thus eggs were obtained from three broodstock, farmed, wild/fed and wild/unfed, and lipid content, lipid class composition, fatty acid composition and pigment content were determined and related to performance parameters including fertilization rate, symmetry of cell division and survival to hatching. Eggs from farmed broodstock showed significantly lower fertilization rates, cell symmetry and survival to hatching rates than eggs from wild broodstock. There were no differences in total lipid content or the proportions of the major lipid classes between eggs from the different broodstock. However, eggs from farmed broodstock were characterized by having significantly lower levels of some quantitatively minor phospholipid classes, particularly phosphatidylinositol. There were no differences between eggs from farmed and wild broodstock in the proportions of saturated, monounsaturated and total polyunsaturated fatty acids. The DHA content was also similar. However, eggs from farmed broodstock had significantly lower levels of AA, and consequently significantly higher EPA/AA ratios than eggs from wild broodstock. Total pigment and astaxanthin levels were significantly higher in eggs from wild broodstock. Therefore, the levels of AA and phosphatidylinositol, the predominant AA‐containing lipid class, and egg pigment content were positively related to egg quality or performance parameters such as fertilization and hatching success rates, and cell symmetry.