军曹鱼对营养物质的需求

军曹鱼(Rachycentron canadum)俗称海鲡,又称海龙鱼、海竺鱼、竹五、海于草、锡腊白等,属鲈形目、鲈亚目、军曹鱼科、军曹鱼属.军曹鱼是近年来发展迅速的一种近岸网箱养殖鱼类,广泛分布于除东太平洋以外的热带亚热带等水温较高的海域[1].我国沿海亦有分布,但产量较低.     

军曹鱼幼鱼日粮锌最适添加量的研究

在以卵白蛋白为蛋白源的基础饲料（Zn含量为5．65mg／kg）中添加10、20、30、40、50mg／kg以ZnSO4为Zn源的Zn,使饲料中总Zn含量为15．97、25．66、33．90、45．85、55．88mg／kg。投喂军曹鱼幼鱼8周。试验结果表明,基础饲料组鱼出现生长不良、厌食、皮肤糜烂和白内障等症状,其成活率、增重率、血清碱性磷酸酶活性（AKP）显著低于添加Zn组（P〈0．05）,骨骼、肌肉、血清和肝脏Zn含量也表现出相同趋势。10mg／kg和20mg／kgZn添加量组鱼仍出现缺Zn症状,各项测定指标随Zn添加量的增加而增大。当饲料中Zn添加量达到30mg／kg时,各项指标趋向稳定,与添加量40mg／kg和50mg／kg组无显著差异。以增重率和骨骼Zn含量为主要评价指标,通过回归分析表明,以ZnSO4为Zn源时,军曹鱼幼鱼日粮Zn的最适添加量为42．86mg／kg。     

军曹鱼的养殖与配合饲料

军曹鱼(Rachycentron canadum)是当前最热门的研究对象和未来最被看好的潜力鱼种之一。军曹鱼亦称龙鱼或海龙鱼,是中型的热带、亚热带海洋性鱼,在23~29℃的水中生长迅速,1年即可长至5~6 kg上市[1,3]。军曹鱼个体大、生长快、抗病力强,适宜高密度集约化养殖,产量高,效益好;同时军曹鱼营养丰富,肉质细腻,丰腴,爽嫩,味道鲜美,口感好,既可生吃、熟食,也可腌和熏制,储存食用,还可以冷冻保存,且肉质感很好,是一个新的全球海产食品,仅日本就约需要2.0×105t/年高价位、高质量的军曹鱼生鱼片。但2000年台湾出口到日本的军曹鱼仅为0.2×104t。市场潜…     

养殖军曹鱼稚鱼骨骼畸形研究

本研究采用软骨—硬骨双染色技术对常规养殖条件下的军曹鱼(Rachycentron canadum)稚鱼全骨骼进行染色,观察并分析其骨骼畸形发生部位及相应的畸形类型。结果显示,在同一批次繁育的180个军曹鱼稚鱼(25日龄)骨骼标本中,有72个标本存在畸形情况,畸形率为40.00%。骨骼畸形类型共计22种,畸形率由高到低主要表现为米克尔氏软骨畸形、尾上骨缺失、脉棘分叉、基舌骨异位和尾上骨愈合等;所有骨骼畸形均未表现出显著可见的外部形态变化。但正常个体与骨骼畸形个体的全长存在极显著差异(P<0.01)。本研究表明,骨骼畸形对军曹鱼生长产生了影响。本研究为探索鱼类骨骼畸形的发生过程和原因、减少畸形率和优化苗种培育养殖条件提供了理论基础。     

丙氨酰—谷氨酰胺和维生素E对军曹鱼的影响

本研究探讨了添加不同剂量和比例的丙氨酰—谷氨酰胺和维生素E对军曹鱼幼鱼相对质量增加率、特定生长率和不同组织器官RNA/DNA比值的影响。在饲料中添加不同剂量和比例的丙氨酰—谷氨酰胺和/或维生素E,饲喂军曹鱼幼鱼12周后,称其体质量,计算相对质量增加率和特定生长率,测定肝脏、肌肉、脑、心脏、肾和血清的RNA和DNA含量,计算RNA/DNA比值。将鱼特定生长率与各组织器官RNA/DNA比值做线性回归方程分析,比较二者的相关性。结果显示,添加丙氨酰—谷氨酰胺、维生素E可促进幼鱼的特定生长率。试验鱼主要组织器官RNA/DNA比值与特定生长率的线性回归相关系数r2的大小为肌肉血清肝脏肾心脏脑。其中鱼肉RNA/DNA比值与其特定生长率的线性回归相关系数r2=0.8422,血清RNA/DNA比值与特定生长率的线性回归相关系数r2=0.82705,均呈高度正相关。由此得出结论,在本试验条件下,添加丙氨酰—谷氨酰胺和/或维生素E可促进军曹鱼幼鱼的相对质量增加率和特定生长率,也增加其主要组织器官RNA/DNA比值;当每千克干饲料添加丙氨酰—谷氨酰胺5g和维生素E 50IU时,效果最佳。军曹鱼幼鱼的特定生长率与其肌肉、血清的RNA/DNA比值高度正相关,可互为指示。     

军曹鱼淋巴器官发育的形态学研究

运用组织学及组织化学的染色方法,对出膜后第1～44天(Days post-hatch,dph)的军曹鱼Rachycentron canadum头肾、脾脏和胸腺发育过程进行研究.首先观察到前肾管,3 d后,在肾管附近发现原始的造血千细胞,逐渐有红细胞和大淋巴细胞产生.之后,脾脏出现,其内毛细血管和红细胞丰富,还分布少量巨噬细胞.胸腺虽然是最后出现的淋巴器官,但是发育的非常快,内外分区明显.可以得出其淋巴器官出现顺序是头肾、脾脏和胸腺.在小淋巴细胞出现前,发现各淋巴器官内存在一些与非特异免疫机制相关的细胞,如巨噬细胞和网状细胞等.淋巴器官原基出现后开始淋巴化,其顺序是胸腺、头肾和脾脏.在采样的时间段里未观察到浆细胞,可能军曹鱼淋巴器官至此仍未发育成熟.     

Factors Affecting Survival of Cobia,Rachycentron canadum,during Simulated Transport

Interest in cobia, Rachycentron canadum, culture has shown significant growth in recent years, but few hatcheries are available to support this developing industry. To facilitate the transport of cobia between facilities, four 24‐h experiments were conducted to examine the effects of density, temperature, and actual versus simulated transport on juvenile cobia (1.5–3.0 g) survival. Mortality during actual transport at fish densities of 5, 10, and 15 kg/m³ (2.9 ± 0.6, 2.9 ± 1.8, and 6.3 ± 0.8%, respectively) did not differ by treatment but was significantly higher than that during simulated transport at each density (0%). No differences in mortality were found following simulated shipping at 19, 21, and 25 C at 15 kg/m³. Significantly greater mortality occurred when juveniles were packed at 25 kg/m³ (10.4 ± 0.7%) than at 20 kg/m³ (1.9 ± 1.6%) and 15 kg/m³ (0.1 ± 0.1%). Recovery following simulated and actual shipping was high in all treatment groups. Under the conditions examined, results indicate that transport density should not exceed 20 kg/m³.     

中国近海军曹鱼线粒体细胞色素b基因序列的遗传变异

测定了连云港、舟山、防城群体34 ind军曹鱼(Rachycentron canadum)线粒体细胞色素b基因883 bp序列,共检测到5个变异位点,发现6个单倍型,平均单倍型多样性(h)和核苷酸多样性(π)分别为0.324和0.000 4,总体表现出较低的遗传多样性;其中连云港群体遗传多样性最高,单倍型多样性和核苷酸遗传多样性分别为0.473±0.162和0.000 57±0.005 93;而舟山群体没有任何变异。连云港与舟山、防城群体间的FST值分别为0.029(P=0.00)与0.042(P=0.00),舟山与防城群体间的FST为-0.048 03(P=0.00),表明连云港与其它两个群体间仅有较低的分化而舟山与防城群体间无明显分化。分子方差分析(AMOVA)表明,3个群体的遗传变异大部分来自于群体内(74.45%,P=0.000)。军曹鱼单倍型拓扑结构呈星状排列,将3个群体作为一个整体进行Tajimas D和Fu’s Fs分析,二者均为显著负值(FST=-1.922 40,P﹤0.00;FST=-5.735,P﹤0.00),表明军曹鱼在历史上经历了种群的扩张,根据τ的观察值0.364,估算出军曹鱼种群扩张时间约为3.1~1.2万年,即末次冰盛期。     

Effects of Salinity on Growth and Energy Budget of Juvenile Cobia,Rachycentron canadum

The effects of salinity on the growth and energy budget of juvenile cobia, Rachycentron canadum, were evaluated. Triplicate tanks with ten fish per tank (initial weight 17.58 ± 0.26 g/fish, mean ± SD) reared at salinities of 5, 10, 15, 20, 25, 30, and 35 ppt were fed with fresh squid to satiety for 15 d. Results indicated that there were no significant differences in daily ration level in wet weight (RL_w), dry weight (RL_d), and energy (RL_e) of the fish. There were also no significant variations in daily fecal production (f_e) and apparent digestibility coefficient of energy (ADC_e) among salinity treatments. Specific growth rates (SGRs) in wet weight (SGR_w), dry weight (SGR_d), and energy (SGR_e) showed domed curves relative to salinity. Quadratic regression analyses of SGR_w, SGR_d, and SGR_e against salinity indicated that the optimal salinity for maximal growth of juvenile cobia was 29.9, 29.9, and 28.5 ppt, respectively. Similar to the trend of SGR, food conversion efficiency for juvenile cobia in wet weight (FCE_w), dry weight (FCE_d), and energy (FCE_e) increased with the increases in salinity, maximized at 30 ppt, and then decreased when salinity reached 35 ppt.     

军曹鱼幼鱼商品饲料中铁、锌适宜添加量的研究

在军曹鱼幼鱼商品饲料中添加铁100、200、300 mg/kg,添加锌30、110、190 mg/kg,共投喂56 d.试验结束时测定,军曹鱼成活率、质量增加率、红细胞含量、肌肉铁含量、骨骼铁、锌含量和肝脏铁、锌含量明显受饲料中铁、锌添加量的影响;血清碱性磷酸酶活性受铁、锌交互作用影响显著,饲料系数主要受铁锌交互作用的影响.以成活率和质量增加率为评价指标,军曹鱼幼鱼商品饲料中铁和锌适宜添加量分别为200 mg/kg和110 mg/kg.     

饲料中矿物质添加量对军曹鱼生长的影响

在饲料中分别添加1％、3％、5％、7％和9％的复合矿物质作试验饲料，饲养军曹鱼70天。以研究不同矿物质添加量对军曹鱼生长的影响。测定了相对增重率、饲料系数、成活率以及肥满度。结果表明，各组的成活率之间没有显著差异，但添加7％复合矿物质的组军曹鱼的相对增重率最大，饲料系数最低，肥满度也最好。各个指标显示出良好的一致实验结果。     

The Apparent Digestibility Coefficients of 13 Selected Animal Feedstuff for Cobia,Rachycentron canadum

The apparent digestibility coefficients (ADCs) of crude protein, lipid, phosphorous, and amino acids, as well as energy, of 13 animal feedstuffs were determined for cobia, Rachycentron canadum (initial weight 130.0 g). The feedstuffs tested included five types of fishmeal, two of blood meal, one of poultry meat meal, two of meat‐and‐bone meal, two of feather meal, and one type of shrimp meal. A reference diet was formulated and the test diets contained 70% of the reference diet and 30% of each feedstuff. The ADCs of crude protein, lipid, energy, phosphorous, and amino acids of the test ingredients ranged from 68.97 to 92.5%, 69.3 to 95.7%, 77.5 to 98.3%, 58.2 to 80.1%, and 72.5 to 97.0%, respectively. The ADCs of crude protein of white fishmeal, steam‐dried brown fishmeal, imported flame‐dried fishmeal, spray‐dried blood cells, poultry byproduct meal, meat‐bone meal, and meat meal were significantly higher than those of dried blood meal, fermented feather meal, and hydrolyzed feather meal (P < 0.05). The ADCs of lipid of dried blood meal and hydrolyzed feather meal were significantly lower than those of other feedstuffs (P < 0.05). The ADCs of energy of fermented feather meal and hydrolyzed feather meal were significantly lower than those of other feedstuffs (P < 0.05) and the ADCs of phosphorus of white fishmeal, steam‐dried brown fishmeal, and imported flame‐dried fishmeal were significantly higher than those of the other ingredients (P < 0.05).     

军曹鱼dnd基因cDNA克隆及其在性腺周年发育过程中的表达

本研究通过cDNA末端快速扩增技术(RACE)克隆了军曹鱼(Rachycentron canadum)dnd基因(Rcdnd)的cDNA序列,全长1339bp,其中,5'非编码区59bp,3'非编码区173bp,开放阅读框(ORF)1107 bp,共编码368个氨基酸.Rcdnd氨基酸序列含有1段RNA识别保守基序(R...     

Pond Culture of Larval and Juvenile Cobia,Rachycentron canadum,in the Southeastern United States

Abstract

The potential of growing larval and juvenile cobia, Rach-ycentron canadum, in ponds was investigated. Larval cobia, obtained from tank spawning of wild-caught adults, were stocked 48-72-h post-hatch at a rate of 700,000/ha into three fertilized 0.25-ha ponds. At one week post-stocking (WPS), fish were observed consuming formulated feed. Growth was rapid, with specific growth rates (SGR) ranging from 12.5-19.2% body weight/day. At harvest (5 WPS) fish reared in two ponds weighed 7.9 and 9.3 g and total length (TL) was 118.9 and 129.3 mm, respectively (all fish reared in remaining pond died the night prior to harvest due to aerator failure). Feed conversion ratio (FCR) was 3.8 for both ponds and survival was 5.3 and 8.5%. Low survival rates were thought to be due primarily to cannibalism. Immediately after harvest, fish were restocked into two 0.25-ha ponds at a stocking rate of 14,400/ ha. Fish were fed formulated, pelleted feeds. Growth was rapid up to ～9 WPS, after which pond water temperatures declined. Ponds were harvested at 13 and 15 WPS, respectively. Final weight of fish was 309.9 and 362.5 g. Final TL was 343.1 and 355.7 mm. FCR was 3.8 and 4.5 and survival was 27.5 and 30.5%. Major losses of fish were associated with avian predators and possibly a toxic algal bloom. Results of trials indicate that cobia larvae and juveniles can be reared in pond-based culture systems, however additional research is needed to refine this approach.     

利用微卫星标记分析军曹鱼养殖群体的遗传多样性

利用12个微卫星标记对北海(BH)、陵水(LS)、硇洲(NZ)、徐闻(XW)和三亚(SY) 5个军曹鱼(Rachycentron canadum)养殖群体进行遗传多样性分析。结果显示,12对微卫星引物在5个军曹鱼养殖群体中共检测到129个等位基因。各养殖群体的平均等位基因数为3.833~6.750,平均有效等位基因数为2.284~3.645,平均观测杂合度和平均期望杂合度分别为0.481~0.635和0.533~0.681,平均多态信息含量为0.463~0.630;哈迪-温伯格平衡检测结果显示,各群体在多个微卫星位点上均显著偏离平衡(P<0.05);军曹鱼养殖群体间的遗传分化指数(Fst)为0.055~0.150,遗传距离(D)为0.240~0.635,其中,BH和NZ的Fst最大(0.150),D最远(0.635);AMOVA分析表明,军曹鱼养殖群体的84%遗传变异来自于个体之间;基于Nei´s遗传距离构建的UPGMA系统进化树显示,BH和SY聚为一支,LS和XW聚为一支,两支聚为一支后与NZ聚为一支。研究结果将为军曹鱼种质资源保护和改良等提供科学的数据参考。     

Effects of Salinity on Growth, Survival, and Selected Hematological Parameters of Juvenile Cobia Rachycentron canadum

Cobia Rachycentron canadum juveniles (119.7 mm TL, weight 8.5 g) were reared for 10 wk at three salinity levels: 5 ppt, 15 ppt. and 30 ppt. Growth and survival were determined through biweekly sampling. Blood samples obtained at termination of the study were analyzed to determine hematocrit, blood osmolality, and total protein. Results indicated that the overall growth of fish was significantly affected by salinity. Mean (± SE) total length (TL) and weight of fish reared at a salinity of 30 ppt were 201.7 ± 2.6 mm and 47.6 ± 1.9 g, respectively, followed by fish reared at 15 ppt (182.2 ± 1.7 mm, 34.1 ± 1.6 g). and 5 ppt (168.3 ± 5.8 mm TL, 28.3 ± 2.3 g). Differences in specific growth rates among treatments for the 10-wk period were also significant. No differences were detected in mean survival among fish reared at salinities of 5, 15, and 30 ppt (84, 94, and 94%, respectively). However, fish reared at salinity 5 ppt appeared to be in poor health as skin lesions, fin erosion, and discoloration were evident. Analysis of blood revealed that, while no differences existed among treatments with respect to plasma total protein, fish reared at a salinity of 5 ppt exhibited significantly reduced hematocrit (25% vs. > 30%) and plasma osmolality values (318 vs. > 353 mmolkg) relative to fish reared at higher salinities. Cobia can tolerate exposure to low salinity environments for short periods of time without mortality; however, moderate to high salinities are required for sustained growth and health of this species.     

Relative contribution of alternative proteins to the growth of Juvenile Cobia,Rachycentron canadum (Linnaeus)

Five isonitrogenous and isocaloric diets were fed to juvenile cobia, to assess the relative contribution of different proteins (fish meal, soybean meal, corn gluten and beer yeast) to the growth of cobia. The dietary effects on nitrogen and carbon turnover and on the isotopic diet‐consumer discrimination factors (Δ¹⁵N and Δ¹³C) were also assessed. Growth results showed that the final body weight, growth rate, feed conversion ratio and protein efficiency ratio of cobia fed diets with alternative protein were significantly lower (P < 0.05) than cobia fed diet formulated with 100% fish meal. The estimated half‐lives of nitrogen and carbon ranged between 9–11 days and 6–8 days, respectively, with significant differences among treatments (P < 0.05). Δ¹⁵N ranged between 0.0–1.2‰ and ?0.1–1.6‰ in whole fish and muscle and Δ¹³C ranged between 3.8–5.1‰ and 4.0–5.1‰ in whole fish and muscle respectively. Diets were formulated with low levels of dietary nitrogen (10%) supplied by alternative protein sources substituting fish meal. The relative contributions of the dietary nitrogen supplied from these sources to the growth of whole fish and muscle tissue ranged between 4.9–5.2% and 5.9–7.7% respectively. Results indicated that growth accounted for the majority of observed isotopic change in animals under all treatments. In whole animals and muscle tissue, isotopic change due to metabolism occurred faster for carbon stable isotopes than for nitrogen stable isotopes. Cobia fed diets formulated with alternative proteins showed reduced nitrogen turnover rate and increased Δ¹⁵N.     

不同饲料对军曹鱼组织消化酶活力的影响

比较研究了投喂冰鲜鱼和人工配合饲料的军曹鱼胃、前肠以及肝脏消化酶(蛋白酶、胰蛋白酶、淀粉酶和脂肪酶)活力.试验结果表明,(1)蛋白酶活力:前肠与肝脏的蛋白酶比活力,投喂配合饲料组显著高于冰鲜鱼组(P<0.05),而胃中的蛋白酶比活力以冰鲜鱼组显著高于配合饲料组(P<0.05);(2)胰蛋白酶活力:胃中胰蛋白酶比活力,冰鲜鱼组显著高于配合饲料组(P<0.05),前肠与肝脏的胰蛋白酶比活力配合饲料显著高于冰鲜鱼组(P<0.05);(3)淀粉酶活力:胃中的淀粉酶比活力,冰鲜鱼组显著高于配合饲料组(P <0.05),前肠的淀粉酶比活力则是配合饲料组显著高于冰鲜鱼组(P<0.05),两种饲料对军曹鱼肝脏淀粉酶比活力影响不显著(P>0.05);(4)脂肪酶活力:胃及前肠的脂肪酶比活力两种饲料间差异不显著(P>0.05),但肝脏的脂肪酶比活力则以配合饲料组显著高于冰鲜鱼组(P<0.05).