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101.
SUMMARY: Thirty immature juvenile grouper Epinephelus coioides (19–168 g bodyweight, BW) were randomly stocked in four units 6 t tanks to determine if mibolerone can be used to induce sex inversion in groupers. After acclimatization and weaning to artificial feed, the feed given daily (4% BW/day) was supplemented with 0, 50, 100, and 200 μg mibolerone/kg feed for about 18 weeks. Thereafter, the hormone treatment was withdrawn and the experiment was terminated at Week 24. Ten fish were killed for gonad histology at stocking to serve as an initial control while about three to five fish were killed every 8 weeks. In general, ovaries of initial controls showed the presence of moderate stromal cells and gonia and few primary oocytes. At Weeks 8 and 16, ovaries of the control fish (0 μg/kg) were similar to that of the initial control except that primary oocytes increased at Week 24. Gonads of fish fed diets containing 100 and 200 μg/kg had none to moderate spermatocytes and few spermatids at Week 8 and 16, although spermatozoa were not observed, indicating that the fish were undergoing spermatogenesis. Spermatogenesis at 50 μg/kg was not as advanced since only few spermatocytes occurred at Weeks 8 followed by moderate gonia and no spermatocytes and spermatids at Week 16. However, the presence of few primary oocytes was observed when mibolerone was withdrawn suggesting that sex-inversed fish reverted back to a female condition. These results show that sex inversion in juvenile grouper can be induced by oral administration of mibolerone and may have possible application on mature females to produce functional males.  相似文献   
102.
为观察饲料中维生素E水平在云纹石斑鱼(Epinehelus moara)幼鱼抗氨氮胁迫中的作用,试验配制了维生素E水平分别为11.09、47.52、91.38、134.57、178.92 mg/kg的试验饲料,饲喂初始体重为(15.6±0.2)g的云纹石斑鱼幼鱼56 d后进行6 h氨氮胁迫,测定其血清葡萄糖(GLU)、乳酸(LD)、皮质醇(COR)、丙二醛(MDA)含量,超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GSH-Px)活力,总抗氧化能力(T-AOC)以及肝脏SOD活力和MDA含量对氨氮胁迫的响应。每个维生素E水平设3个网箱(重复),每个网箱放养20尾鱼。结果显示:各组血清中GLU含量在饲喂前后无显著差异(P0.05),氨氮胁迫后血清中GLU含量随饲料中维生素E水平的升高而降低。氨氮胁迫后血清中LD含量与饲料中维生素E水平呈反比,并在饲料中维生素E水平达到47.52 mg/kg之后维持稳定。氨氮胁迫后各组血清中COR含量都有显著升高(P0.05)。当饲料中维生素E水平达到47.52 mg/kg后,饲喂56 d后再氨氮胁迫对血清和肝脏中SOD活力不产生显著影响(P0.05)。血清中CAT活力在饲喂后和氨氮胁迫后均有下降的趋势,当饲料中维生素E水平达到或超过91.38 mg/kg时不论饲喂后还是氨氮胁迫后,血清中CAT活力变化都不显著(P0.05)。在低维生素E水平(11.09和47.52 mg/kg)下,血清和肝脏中MDA含量在氨氮胁迫后均呈显著上升(P0.05);在高维生素E水平(91.38、134.57、178.92 mg/kg)下,血清和肝脏中MDA含量在氨氮胁迫后没有产生显著差异(P0.05)。在饲料维生素E水平达到或超过91.38 mg/kg时,饲喂后血清中GSH-Px活力均显著上升(P0.05),氨氮胁迫后血清中GSH-Px活力则无显著变化(P0.05)。在饲料维生素E水平达到或超过47.52 mg/kg时,血清T-AOC在饲喂后呈现显著升高(P0.05),而氨氮胁迫后又出现下降的趋势。由此得出,在本试验条件下,饲料中维生素E水平与云纹石斑鱼幼鱼的抗应激和抗氧化能力具有相关性,饲料中维生素E水平达到或超过91.38 mg/kg可有效地提高云纹石斑鱼幼鱼的抗应激和抗氧化能力。  相似文献   
103.
本试验旨在探讨饲料中牛磺酸含量对斜带石斑鱼生长性能、体成分及组织游离氨基酸含量的影响。以酪蛋白和明胶为蛋白质源配制低牛磺酸含量的基础饲料,在基础饲料中分别添加0(对照)、0.4%、0.8%、1.2%、1.6%的牛磺酸,配制成5种试验饲料。将300尾平均体重为(19.14±0.06)g斜带石斑鱼幼鱼随机分为5组(每组3个重复,每个重复20尾),每组投喂1种试验饲料,饲养周期为56 d。结果表明:与对照组相比,各牛磺酸添加组试验鱼的增重率、摄食率和饲料效率均显著增加(P0.05),内脏指数显著降低(P0.05),肝脏指数、肥满度无显著变化(P0.05)。与对照组相比,各牛磺酸添加组试验鱼全鱼粗蛋白质含量显著升高(P0.05),全鱼粗脂肪含量显著降低(P0.05),全鱼水分和粗灰分含量则无显著变化(P0.05)。各牛磺酸添加组试验鱼肝脏和肌肉中总非必需氨基酸、总氨基酸、游离丝氨酸含量以及肝脏游离蛋氨酸含量均显著低于对照组(P0.05)。试验鱼血清、肝脏、肌肉和全鱼中牛磺酸含量随饲料中牛磺酸含量的增加而呈上升趋势,且与饲料中牛磺酸含量存在显著正相关关系(r0.907,P0.05)。随饲料中牛磺酸含量的增加,肝脏牛磺酸保留率呈上升趋势,而肌肉中牛磺酸保留率则呈先上升后下降的趋势;此外,各组试验鱼肌肉牛磺酸保留率均高于肝脏。由此得出,饲料中一定含量的牛磺酸能促进斜带石斑鱼生长和摄食,降低全鱼脂肪沉积,增加全鱼蛋白质沉积,降低组织中游离氨基酸含量。以增重率为指标,通过回归分析得出斜带石斑鱼饲料中牛磺酸的适宜含量为1.04%。  相似文献   
104.
[目的]研究赤点石斑鱼(Epinephelus akaara)FAS基因的结构与表达特性。[方法]以前期获得的转录组序列作为数据库,应用PCR技术,获得赤点石斑鱼FAS基因的c DNA全序列。[结果]该序列与大黄鱼(Larimichthy scrocea)FAS基因的相似度最高,为87%。该序列全长8 505 bp,包括712 bp的3'UTR区、7 548 bp的开放阅读框(ORF)以及245 bp的5'UTR区,可编码2 515个氨基酸。经预测,该蛋白分子量为274.03 ku,等电点为5.98,其属于亲水性蛋白。通过Real-time PCR方法获得FAS在赤点石斑鱼各个组织中的表达,结果显示,其在心脏中表达量最高,其次是在肝脏中。FAS基因的进化与物种进化一致。[结论]该研究为进一步研究赤点石斑鱼脂肪代谢奠定理论基础,也为赤点石斑鱼在养殖方面的工作提供基础资料。  相似文献   
105.
A 70‐day experiment was implemented to study the iron (Fe) bioavailability of three Fe sources in Epinephelus coioides (initial weight, 12.19 ± 0.14 g). Treatments consisted of 0, 50, 90, 130, 170 and 210 mg supplemental Fe/kg from iron sulphate (FeSO4), ferric citrate (Fe‐citrate) and hydroxy methionine analogue iron (Fe‐MHA). The results showed that the growth performance was not affected by Fe level regardless of Fe sources. Hepatic catalase activity (CAT), the haematocrit value (Hct), haemoglobin (Hb), mean corpuscular volume (MCV) and Fe content in whole body or liver firstly increased significantly and then plateaued as Fe level increased regardless of the Fe source, except significant decreasing of Hct in 210 mg Fe/kg group from FeSO4. Manganese (Mn) content decreased significantly and then kept stable in the whole body and liver whatever the source was. The slope‐ratio method using FeSO4 as the reference and Hb content, CAT activity, body and hepatic Fe concentration as the response parameter showed the average relative bioavailability of Fe‐citrate and Fe‐MHA was 103.25 ± 4.35 (n = 4) and 134.5 ± 15.67 (n = 4), respectively, with the maximum value of Fe‐MHA in any case. In conclusion, Fe‐MHA was the most effective to meet preferable haematological index, CAT activity and mineral deposition, with little difference between Fe‐citrate and FeSO4, athough Fe levels with different sources failed to influence the growth in grouper.  相似文献   
106.
本文对鞍带石斑鱼(Epinephelus lanceolatus)的胚胎发育、仔鱼形态发育及饵料转变进行了观察研究,详细描述了胚胎发育各个时期的形态特征。鞍带石斑鱼受精卵在水温29±0.5 ℃、静水微充气、盐度30的孵化条件下,经过18 h 30 min仔鱼开始孵化出膜。胚胎发育过程分为卵裂期、囊胚期、原肠胚期、神经胚期和器官形成期。在水温25.0~30.0 ℃和盐度33.0 ~35.0的室外水泥池进行初孵仔鱼的培育试验,仔鱼在孵化出膜后72h开口摄食。4日龄仔鱼的卵黄囊几乎完全消失,开始摄食原生动物;从5日龄开始,摄食行为明显,摄食原生动物和小轮虫; 8日龄仔鱼逐渐转向摄食桡足类,兼食少量的轮虫;13日龄后,仔鱼的饵料以桡足类成体为主,摄食量大;经过21天培育进入稚鱼期。  相似文献   
107.
为了评估我国斜带石斑鱼野生群体与人工繁殖群体的种质现状,采用19个微卫星标记对斜带石斑鱼南海野生群体和海南人工繁殖群体进行遗传多样性研究。结果显示,在野生和人工繁殖群体中,19个基因座位的有效等位基因数(Ne)分别为1.135 0~4.516 2和1.00 0~3.982 7;群体平均观测杂合度(Ho)分别为0.706 1和0.687 5;群体平均期望杂合度(He)分别为0.480 3和0.421 5;多态信息含量(PIC)分别为0.547 5和0.493 0;2个群体间的遗传相似系数(Gst)为0.979 4,遗传距离(D)为0.020 8。这表明斜带石斑鱼南海野生群体与人工繁殖群体的遗传多样性仍然比较丰富,人工繁殖群体没有出现明显的遗传分化和种质退化的现象。  相似文献   
108.
An inactivated betanodavirus, red‐spotted grouper nervous necrosis virus (RGNNV), is a vaccine candidate for viral nervous necrosis (VNN). The present study was conducted to examine inoculation doses of the vaccine and neutralizing antibody titre levels to protect fish against VNN. Young sevenband grouper, Epinephelus septemfasciatus, averaging 25.4 g, were immunized at 25 °C water temperature by a single intraperitoneal injection of formalin‐inactivated RGNNV. Fish immunized at vaccine doses of 108.5, 108.0, 107.5, 107.0 and 106.5 TCID50 per fish produced antibodies at mean titres of 1:907, 1:511, 1:259, 1:197 and 1:96, respectively, at 20 days post‐immunization (p.i.). Neutralizing antibodies were not detected in any control fish (titre <1:80). When fish were challenged with RGNNV (105.0 and 104.0 TCID50/fish) at 20 days p.i., cumulative mortalities of the fish groups immunized with 108.5, 108.0, 107.5 and 107.0 TCID50 per fish were significantly lower than those of the control group, and the relative percent survival values were higher than 60% in fish groups immunized with 107.5 TCID50 per fish or higher doses. However, no significant differences were found in mortality between the group immunized with 106.5 TCID50 per fish and the control group. From these results, it was deduced that the minimum effective inoculation dose of the vaccine is 107.0 TCID50 per fish and the minimum mean neutralizing antibody titre giving significant protection is approximately 1:200. This antibody titre level is a possible measure of vaccine efficacy against VNN in sevenband grouper, instead of a virus challenge test.  相似文献   
109.
An ichthyoplankton survey was conducted at the periphery of Cabrera National Park (Balearic Islands, Western Mediterranean Sea) in July 2004, using bongo nets, fixed nets and collection of oceanographic data. This work focused on analysing the distribution of eggs and larval stages of some fishery‐targeted taxa (Coris julis, Epinephelus spp., Sciaena umbra and Scorpaena sp.) whose adult abundances and/or biomass are higher in the reserve and therefore would be likely to show gradients of larval abundance attributable to the existence of the Marine Protected Area (MPA). Oceanographic data indicated there was water column stratification, horizontal distribution of surface water masses and hydrodynamic features linked with Mediterranean seasonality. During the summer sampling, eggs and larvae of targeted fish taxa were mainly located in the northeast of the MPA, near the coast. An effect of depth and current was demonstrated for Coris julis and Epinephelus spp. and there appears to be an offshore gradient for the other targeted taxa, especially for the egg stages. These data highlight the fact that the Cabrera archipelago is a potential important spawning area for targeted fishery species.  相似文献   
110.
A total of 210 Epinephelus fuscoguttatus (brown‐marbled grouper) was examined for parasites. During three consecutive seasons (two rainy and one dry season from 2002 to 2004), 35 specimens each taken from floating net cages of the National Sea Farming Development Centre (Balai Budidaya Laut) and from wild catches in Lampung Bay, South Sumatra, Indonesia were studied. Twenty‐five (cultured grouper) and 30 (wild grouper) parasite species/taxa were identified, with an infracommunity ranging from one to nine (cultured) and three to 14 parasite species (wild), demonstrating a species‐rich parasite fauna even in the cultured fish. Protozoans (1 species), microsporeans (1), myxozoans (1), digeneans (8), monogeneans (5), cestodes (3), nematodes (8), acanthocephalans (2) and crustaceans (6) were found. The most abundant parasites were the monogeneans Pseudorhabdosynochus epinepheli and Pseudorhabdosynochus lantauensis for both, cultured and wild grouper during all seasons. For the cultured fish, the prevalence of monoxenous ectoparasites (e.g. P. epinepheli, P. lantauensis, Capsalidae gen. et sp. indet., Benedenia epinepheli) was in most cases higher than that of heteroxenous endoparasites. This contrasts the wild grouper, where heteroxenous parasites such as Allopodocotyle epinepheli and Raphidascaris sp. occurred at a similar prevalence compared with the fairly abundant Pseudorhabdosynochus spp. No seasonality of infestation was observed for both cultured and wild fish. The high levels of infestation of potentially pathogenic monogeneans throughout the year could result in significant parasite outbreaks at the locality studied.  相似文献   
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