Induced Spawning of Nassau Grouper Epinephelus striatus

Nassau grouper Epinephelus striurus females ovulated 48–51 h after the first of two intramuscular injections of human chorionic gonadotropin given 24 h apart (usually 0.7 IU/gram body weight). Typical spawns contained 400,000–600,000 eggs. With fresh milt and clean water, fertilization rate was 85 and 86%. Survival from fertilization to first feeding for six spawns was 73–94%.     

人工诱导青虾成熟和产卵

本文研究了青虾催产的方法。采用注射孕酮;切除眼柄和激光照射复跟等技术,人工诱导青虾成熟和产卵,效果明显。并且孵化出的幼体与自然成熟的卵孵化出的幼体在生长上没有显著差异。     

First Documentation of Male Sexual Maturation in Captivity of Pacific Goliath Grouper,Epinephelus quinquefasciatus

This is the first documentation of male sexual maturation in captivity of Pacific goliath grouper. Males weighed between 15.3 and 16.6 kg and measured 93.5 and 97 cm in total length. No mature females were found during the same 4-year period of observation in captivity.     

Induced Maturation and Spawning of the Chinese Catfish Clarias fuscus

Chinese catfish ( Clarias fuscus ) were successfully spawned in Hawaii using human chorionic gonadotropin (HCG) at dosage rates of two and four international units (IU) per gram body weight. Fish not injected with HCG did not produce viable eggs. Successful spawns with HCG occurred between May and October. Hatch rates of up to 80% were obtained during June, July, and August for those fish given either a 2 or 4 IU per gram body weight injection of HCG. Fish spawned in either May or October yielded significantly higher hatch rates when injected with 4 rather than 2 IU per gram body weight. Fish held at elevated temperatures (28 to 30 C) prior to the normal spawning season developed significantly larger oocyte diameters, 60 days earlier than fish held under ambient temperature conditions (21.5 to 24 C). Photoperiod manipulation at ambient temperature conditions was associated with earlier oocyte maturation, but photoperiod effects were much less important than temperature.     

斜带石斑鱼溶藻弧菌病的研究

从患病的斜带石斑鱼肝和肾组织分离的两株病原菌,进行纯化培养、人工感染、VITEK-AMS-32自动微生物分析鉴定及药敏试验,经形态和生理生化测定,确定为溶藻弧菌(Vibrioalginolyticus)。组织病理变化主要表现为鳃、肝和肾细胞变性、坏死,病变组织炎性细胞浸润,呈变质性炎症。     

Larviculture of the Greasy Grouper Epinephelus tauvina F. and the Brown-Marbled Grouper E. fuscoguttatus F. in Singapore

This paper reports the larviculture of two grouper species, the greasy grouper Epinephelus tauvina and the brown-marbled grouper E. fuscoguttatus , and examines the technical feasibility of breeding the fish. Fertilized eggs for larviculture were obtained by induced spawning through multiple hormonal injections of the female brooders, followed by artificial fertilization for the greasy grouper and by natural spawning in netcages for the brown-marbled grouper.
For both species, larviculture was divided into three operational stages, i.e., stage 1 (day 0–12), stage 2 (from day 12 to day 24 for the greasy grouper and to day 30 for the brown-marbled grouper) and stage 3 (day 24 or 30 to metamorphosis). Larvae were transferred to clean tanks after each stage. Total mortality around day 5–8 was common for the greasy grouper. Several modifications, including the feeding with super-small strain rotifers, intensive feeding of rotifers with Nannochloropsis and the use of an oil-skimmer, have been made to improve the situation. Two other major problems in larviculture were the high mortality observed after day 25 in the greasy grouper and the high cannibalism from day 35 onwards for the greasy grouper and from day 30 onwards for the brown-marbled grouper. The shock syndrome exhibited by both species during the periods made culling of the fish impossible.
Based on the spawning and larval characteristics, brown-marbled grouper is considered a better potential species for large scale fry production than the greasy grouper.     

Growth, Maturation, Induced Spawning, and Production of the First Generation of South American Catfish, Pseudoplatystoma sp., in North America

Growth, plasma steroids, and the appearance of gonads (histology and gonadosomatic index) were followed in South American catfish (surubim, Pseudoplatystoma sp.) raised in captivity in the aquaculture facility at The Ohio State University, Columbus, Ohio, USA, from 2003 until 2006. Broodstock growth showed a great individual variation and it did not seem sex dependent. The levels of 11‐ketotestosterone were high in males during the reproductive season. Three out of six females spawned after receiving two doses of carp pituitary extract (0.5 and 5 mg/kg) at 11‐h intervals. Fertilization was performed in only one female in February 2006. Egg size was 0.73 ± 0.06 mm in diameter at stripping. Two males released sperm, and it was used for fertilization. Sperm concentrations were 24 × 10⁹ and 15.5 × 10⁹ spermatozoa/mL in Male 1 and Male 2, respectively, and viability was confirmed after activation in 0.3% NaCl. Embryo survival at 9 h after fertilization was 44 and 23% for Male 1 and Male 2, respectively. Embryos hatched 15 h after fertilization. Larvae were 3.53 ± 0.09 mm in length at hatching and were successfully raised (72% survival after 2 wks) using live brine shrimp nauplii.     

Larval Development and Rearing of Longtooth Grouper Epinephelus bruneus in Jeju Island, Korea

Eggs and sperm were obtained from a female (6.3 kg/BW) and a male (8.4 kg/BW) longtooth grouper Epinephelus bruneus following HCG injection in July 2003. The eggs were fertilized artMcially with the sperm and incubated in one of two 50-m³ tanks after washing the fertilized eggs. The fertilized eggs were 830–950 pn (average 900 ± 2 μm) in diameter and the respective fertilization and hatching rates were 97.7 ± 0.6% and 96.8 ± 0.5% at a water temperature of 25.0 ± 0.5 C. With this regime, the survival rate by day 93 was 7.5% in the 50-m³ tank. The elapsed time from hatching to opening the mouth was 3 d at 25 C. The initial mouth size (z) of the larvae was 0.22–0.23 mm. The newly hatched larvae were 2.02 ± 0.02 mm TL; this increased to 4.12 ± 0.09 mm TL by day 11. By day 54, the larvae had metamorphosed into juveniles and reached 41.12 ± 1.20 mm TL, and by day 93 the juveniles reached 93.78 ± 1.98 mm TL. In all, 49.5% of the larvae were malformed and the type of malformation was diverse.     

Does Dietary Administration of Lactococcus lactis Modulate the Gut Microbiota of Grouper,Epinephelus coioides

The effect of dietary administration of probiotic Lactococcus lactis MM1 for 60 d on the autochthonous microbiota in the foregut, midgut and hindgut of juvenile grouper, Epinephelus coioides, was evaluated using polymerase chain reaction‐denaturing gradient gel electrophoresis (DGGE). Samples collected from the probiotic and control groups showed different DGGE patterns, while 11 common bands presented in both groups. The similarity dendrogram revealed three different clusters depending on the three sections of the gastrointestinal (GI) tract, and the probiotic triplicates in each GI section were generally clustered into one group distinctly different from the corresponding control triplicates. Increased species richness and Shannon index were observed in the foregut, midgut, and hindgut samples in the probiotic group compared with the control group, which suggested that probiotic L. lactis MM1 could improve the autochthonous microbial diversity along the GI tract of E. coioides. The growth of many potentially beneficial and unidentified bacteria was stimulated by the probiotic, whereas the growth of some potential harmful species, like Staphylococcus saprophyticus, was depressed.     

棕点石斑鱼的肌肉营养成分分析

试验结果表明,棕点石斑鱼的含肉率为77.3%,肌肉中粗蛋白、粗脂肪、粗灰分和水分的含量分别为18.8%、2.2%、1.16%和77.1%;18种氨基酸总量为18.22%(占鲜样),其中人体必需的8种氨基酸含量为6.88%,占氨基酸总量的37.36%,4种鲜味氨基酸含量为7.11%.其氨基酸构成比例符合FAO/WHO标准.必需氨基酸指数(EAAI)为514.DHA和EPA含量丰富,占脂肪酸总量的28.2%.     

Induced Ovulation and Spawning in the Catfish,Clarias isheriensis,Using Pituitary Extracts from Non-piscine Sources

Acetone-dried pituitary extracts obtained from non-piscine sources- the common toad, Bufo regularis; the African bullfrog, Rana adspersa; and chicken, Gallus domesticus, were evaluated as alternative inducement agents to piscine-sourced pituitary extracts to spawn Clarias isheriensis. A single dose of 4 mg of dry pituitary extract per kilogram of female was injected intraperitoneally, and it induced ovulation and spawning in all treatments; there was no significant difference (P > 0.05) in percent fertilization of eggs. All pituitary extracts were effective in inducing ovulation and spawning in C. isheriensis and, therefore, can be used as alternative sources of pituitary hormones.     

IGF-I of Orange Spotted Grouper Epinephelus Coioides: cDNA Cloning, Sequencing and Expression in Escherichia Coli

Insulin-like growth factors I and II (IGF-I and IGF-II) are two highly homologous mitogenic peptides that are expressed ubiquitously and show diverse effects on development, growth, and metabolism. The cDNA encoding IGF-I of a teleost, the orange spotted grouper (Epinephelus coioides) was produced from liver by RT-PCR, and rapid amplification of cDNA ends, RACE. Typically, the deduced 186 amino acid protein contains a signal peptide, B, C, A, D and E domains. On the amino acid level, grouper IGF-I shares 97.3% similarity with black seabream (Sparus macrocephalus) with the differences focusing on the B and C domains. The analysis of the E domain showed that grouper IGF-I belonged to Ea-4 type. When mature amino acid sequence was compared with other vertebrates, it revealed higher similarity with black seabream and halibut, while lower similarity with human and mouse. The expression of IGF-I mRNA in adult tissues was studied using RT-PCR. IGF-I mRNA expression level in the liver was significantly higher than those in the brain and muscles. In other tissues, low amount of IGF-I mRNA expression was also detected. The coding region of IGF-I cDNA for mature IGF-I protein was subcloned into an expression plasmid pTRX and fused with E. coli thioredoxin (Trx). Moreover, we have successfully developed an expression system in E. coli to overproduce recombinant grouper IGF-I. Using western blotting, we found that the fusion protein could blot with antiserum to barramundi IGF-I further confirming the immunoactivity of the recombinant IGF-I.     

配合饲料对青石斑鱼生长和消化酶活性的影响

探讨市售配合饲料对青石斑鱼生长和消化酶活性的影响,为日后研制青石斑鱼的全价配合饲料提供依据.将120尾2龄雌性青石斑鱼随机分成两组,每组3个平行,分别用小杂鱼(对照组)和湿颗粒饲料(试验组)饲喂112 d.从每个平行中随机抽取5尾鱼,测定特定生长率和消化酶活性.试验结果:试验组鱼的特定生长率显著高于对照组(P<0.05);在胃部,试验组鱼的胃蛋白酶活性高十对照组(P<0.05),胰蛋门酶活性低于对照组(P<0.05);在肠道,试验组鱼的脂肪酶、胃蛋白酶活性高于对照组(P<0.05);在肝脏,试验组鱼的脂肪酶、胰蛋白酶活性均低于对照组(P<0.05).结果表明,投喂配合饲料可以显著提高青石斑鱼胃部的胃蛋白酶活性、肠道的脂肪酶和胃蛋白酶活性,但也降低了胃部、肠道和肝脏的胰蛋白酶活性;同时,配合饲料可以提高青石斑鱼的生长速度.     

Observations and Techniques for Maturation, Spawning, and Larval Rearing of the Yellowtail Snapper Ocyurus chrysurus

Abstract.— This paper describes current techniques used at our laboratory for the controlled spawning, maturation and larval rearing of the yellowtail snapper. Juvenile yellowtail snapper were obtained from Florida and transferred to the Fisheries and Mariculture Laboratory in July 1990. Temperature and photoperiod manipulation resulted in precocial spawning in 1991, with sustained successive spawning beginning in February 1992. Average weekly spawning from 1992–1994 was 308,000 and 247,000 eggs/tank, with fertilization rates of 46.1 % and 32.5% for fish maintained in two separate spawning tanks. Observations on spawning activity from 1995 to 1996, during which a decreasing trend in egg and larval quality was observed, imply a possible problem with broodstock nutrition. Evaluation of feeding regimes during this period indicated a shift to a high (almost exclusively) usage of fresh squid and a reduction in fish and shrimp. Returning to a feeding regime of alternating feedings of fresh fish, squid. and shrimp have yielded improved spawning and egg quality. Larval rearing techniques using live and prepared feeds has resulted in an overall survival of 3% from egg to advanced juvenile. Growout of first generation (F1) juveniles yielded a marketable size (1 1b) fish in 25 mo. Spawning of F1 fish hegan in 1998. larval rearing and grow out of F2 fish are currently underway. Results demonstrate that yellowtail snapper culture is technically feasible; however. further research to develop species specific culture techniques will be required before the culture potential of this species can be accurately evaluated.     

维生素C对点带石斑鱼生长及其组织抗氧化性能的影响

采用单因子试验设计方法,研究了饲料中添加维生素C(Vc)对点带石斑鱼生长及组织抗氧化性能的影响。设计Vc含量为5个不同梯度(0、70、210、630、2000mg/kg)的等氮、等能饲料,进行为期6周的饲养试验,每个水平3个重复,每箱40尾。试验结果表明,对照组的质量增加率、特定生长率、存活率均低于各添加组,Vc的添加量为210mg/kg时,质量增加率和特定生长率最高。Vc并不影响鱼体的内脏体比指数和肥满度,却显著影响肝体比指数。以质量增加率为指标,点带石斑鱼饲料中Vc的适宜添加量为210mg/kg。添加Vc可显著提高肝脏、脾及血清中超氧化物歧化酶和过氧化氢酶活力(P<0.05),而头肾、中肾及肌肉中的超氧化物歧化酶和过氧化氢酶变化不大(P>0.05)。Vc添加量为630mg/kg组中,肝脏、脾及血清中超氧化物歧化酶和过氧化氢酶最高,丙二醛含量最低。据此可知,Vc对点带石斑鱼是有效的抗氧化剂。     

澳洲宝石斑鱼疾病防治技术研究进展

澳洲宝石斑鱼（Scortum barcoo Mcculloch ＆ Waite,1917）,是澳大利亚久负盛名的淡水鱼,被认为是最好的垂钓和食用鱼之一,隶属于鲈形目Percifbrmes,鯻科Theraponidae,革鯻属Scortum,其英文学名为高体革鯻（Barcoo grumter）,亦称佳帝（Jadeperch）。我国于2001年从澳大利亚引进,国内俗称宝石鲈、玉鲈、宝石鱼、翡翠鱼等。     

Progress in Controlled Maturation and Spawning of Summer Flounder Paralichthys dentatus Broodstock

Abstract— Wild-caught, adult summer flounder Paralichthys dentatus (avg. wt. = 740 g; range = 264–1,540 g; N = 60), collected in northeastern US coastal waters during October 1994, were transported to Vero Beach, Florida in March 1995 and held in 2.6-m³ indoor tanks through November 1995 under two artificial photothermal regimes: (1) natural regime, simulating natural habitat conditions; and (2) accelerated thermal regime, with seasonal temperature changes advanced by one month. A third group of fish was held in outdoor tanks under ambient photothermal conditions. Under all photothermal conditions, onset of vitellogenesis was associated with declining daylength and temperature, beginning in the accelerated group, then progressing to the natural and the ambient groups. From 20 September to 28 November 1995, 23 vitellogenic stage females from the accelerated and natural regimes were implanted with a cholesterol-cellulose pellet containing LHRH-a (100 μg/kg body wt). Females with initial mean oocyte diameters ranging from 258–456 μm spawned voluntarily 2.5–5.5 d postimplantation, while no maturational response was obtained from females with mean diameters ranging from 165–231 μm. Two females were spawned twice during the study period by LHRH-a pellet implantation. Infrequent, natural spawning without hormone intervention was also obtained. Females released from 22.7–396.9 × 10³ eggs on the first day of spawning, with fertilization and hatching rates of 0–93.470 and 0–81.1%, respectively.     

Evaluation of First-Feeding Regimens for Larval Nassau Grouper Epinephelus straitus and Preliminary, Pilot-Scale Culture through Metamorphosis

Two 10-day hatchery experiments were conducted to evaluate s-type (Hawaiian strain) and ss-type (Thailand strain) rotifers Brachionus plicatilis and cryogenically preserved oyster Crassostrea gigas trochophores as first feeds for larval Nassau grouper Epinephelus striatus. Newly hatched grouper larvae were reared at densities of 11.2–20.8/L in 500-L tanks at 36–38 ppt salinity, 25–26 C, and under a 11-h light: 13-h dark photoperiod. Beginning on day 2 posthatching (d2ph), prey were maintained at a density of 20 individuals/mL, while phytoplankton (Nanochloropsis oculata) was maintained at 500 × 10³ cells/mL. In experiment 1, survival and growth were higher (P < 0.05) for fish fed small s-type rotifers (mean lorica length = 117 μm; fish survival = 7.96%) selected by sieving than for fish fed non-selected rotifers (mean lorica length = 161 μm; fish survival = 2.13%). These results demonstrated the advantage of small prey size and suggested that super-small (ss-type) rotifer strains would be beneficial. In experiment 2, three feeding regimens were compared: 1) ss-type rotifers (mean lorica length = 147 μm); 2) oyster trochophores (mean diameter = 50 μm) gradually replaced by ss-type rotifers from d5ph; and 3) a mixed-prey teatment of 50% oyster trochophores and 50% ss-type rotifers. Survival was higher (P < 0.05) for larvae fed mixed prey (15.6%) than for those fed rotifers (9.73%) or trochophores and rotifers in sequence (2.55%), which also showed the slowest growth. Oyster trochophores, although inadequate when used exclusively, enhanced survival when used in combination with rotifers, possibly by improving size selectivity and dietary quality. In a pilot-scale trial, larvae were cultured through metamorphosis in two 33.8-m³ outdoor tanks. Fertilized eggs were stocked at a density of 10 eggs/L and larvae were fed ss-type rotifers from d2ph-d20ph, newly hatched Artemia from d15ph-d18ph, 1-d-old Artemia nauplii from d18ph-d62ph. Survival on d62ph was 1.17%, with a total of 5,651 post-metamorphic juveniles produced.