Production of second generation penaeid shrimp,Penaeus stylirostris,from Mexico

The life cycle of the penaeid shrimp, Penaeus stylirostris, was completed in captivity with the production of F₂ generation nauplii. Over one million F₂ generation nauplii were harvested from the F₁ generation represented by laboratory-reared adult shrimp. The studies were completed in a laboratory simulated, tropical environment for maturation and spawning, and in pond systems located in a temperate environment for growout of the F₁ generation.     

A new haplosporean infecting the hepatopancreas in the penaeid shrimp, Penaeus vannamei

Abstract. A hitherto unrecorded haplosporean was found in the hepatopancreas of Penaeus vannamei . Multinucleate plasmodia developing within the hepatocytes fragment into unimicleate stages. Eventually the host cells are destroyed and the uninuclear stages are released into the lumen of the secretory tubules. The haplosporosomes are oval, have a thick cortex and contain a small spherical medulla at the broader end. No spores were found and thus the parasite, which is highly pathogenic, could not be assigned any precise taxonomic position.     

Serum constituents of the Malaysian prawn (Macrobrachium rosenbergii) and pink shrimp (Penaeus marginatus)

Baseline serum values of newly captured Malaysian prawns (Macrobrachium rosenbergii) and pink shrimp (Penaeus marginatus) were determined by Sequential Multiple AutoAnalysis. Both of these species have considerable potential for commercial captive culture.Sex differences in serum constituent levels were found within species. Female pink shrimp had higher serum glucose levels than the males. Malaysian prawn males had higher cholesterol levels than females, and the latter had higher levels or activities of urea nitrogen, creatinine and lactic dehydrogenase.Pink shrimp held under laboratory conditions for 10 days had higher levels or activities of serum glucose and alkaline phosphatase and lower levels or activities of serum inorganic phosphorus, total protein, lactic dehydrogenase and glumatic-oxaloacetic transaminase than pink shrimp sampled immediately after capture.     

Morphogenesis of the membranous labyrinth in penaeid shrimp cells infected with Penaeus monodon bacuiovirus (MBV)

The morphogenesis of a highly organized cellular membrane structure, a membranous labyrinth (ML), in the cells of penaeid shrimp infected with Penaeus monodon baculovirus (MBV) is described. The ML possibly originates from dilated Golgi apparatus, endoplasmic reticulum (ER) or the outer nuclear membrane. The ML apparently grows by proliferation of the cellular membranes of these systems. In addition, its degree of development was correlated with stages of MBV reproduction.     

Infection of the yellow head baculo-like virus (YBV) in two species of penaeid shrimp, Penaeus stylirostris (Stimpson) and Penaeus vannamei (Boone)

Abstract. Yellow head baculo-like virus infection and disease were demonstrated experimentally in the two main species of penaeid shrimp cultured in Hawaii and the Western hemisphere. Viral infection was induced by intramuscular inoculation of a 10% suspension of cephalothorax tissue filtrate prepared from two tiger shrimp, Penaeus monodon Fabricius, infected with yellow head disease, into sub-adult (3–10g) P. stylirostris (Stimpson) and P. vannamei (Boone). Signs of disease appeared as early as 2 days post infection (p.i.), and in most cases mortality reached 100% within 5–7 days p.i. Histopathological examination of the infected animals revealed extensive cellular necrosis in ectodermal and some mesenchymal tissues. Electron microscopical examination of thin sections of the gill and hepatopancreas from the infected shrimp revealed non-occluded rod-shaped baculo-like virus particles measuring 130–197 & 45–58 nm which were primarily localized within the cytoplasm of infected cells. The virus particles were contained within cytoplasmic vacuoles, and occurred singly or in small groups of two or more particles.     

Light and electron microscopic evidence of white spot disease in the giant tiger shrimp, Penaeus monodon (Fabricius), and the kuruma shrimp, Penaeus japonicus (Bate), cultured in Taiwan

Since 1992, mass mortalities among cultured giant tiger shrimp, Penaeus monodon (Fabricius), and kuruma shrimp, Penaeus japonicus (Bate), have been observed in Taiwan. The condition is known as 'white spot disease' (WSD), based on the characteristic white spots on the cuticle of diseased shrimp. With the scanning electron microscope, two sizes of white spots were observed. Each spot represented a protrusion on the inside surface of the carapace. The composition of white spots was similar to that of the cuticule, most calcium, as determined with an energy dispersive spectrometer. Histological studies of moribund, infected specimens revealed degenerated cells, characterized by hypertrophied nuclei, in various meso- and ectodermal tissues. Infected tissues included cuticular epidermis, connective tissue, lymphoid organ, antennal gland, and haematopoietic, gill and nervous tissue. Nuclei were Feulgen-positive and no occlusion body was found in the necrotic tissue. Transmission electron microscopy revealed the presence of rod-shaped and enveloped virions in the hypertrophied nuclei. The virions measured 298 ± 21 × 107 ± 8 nm in the giant tiger shrimp and 248 ± 12 × 104 ± 8 nm in the kuruma shrimp. In an experimental infection trial, cumulative mortality was 40% within 14 days under stress conditions. No mortality was observed in controls or in non-stressed infected shrimp. Experimental infections show that environmental stressors such as ammonia may enhance the severity of WSD virus infections in cultured shrimp.     

舟山地区大棚凡纳滨对虾生长缓慢病因的调查分析

2013年以来,浙江省舟山地区大棚养殖的凡纳滨对虾(Penaeus vannamei)普遍出现生长缓慢、养殖成功率低的现象。为了查明该原因,本研究采用分子生物学和组织病理学等方法对引起对虾生长缓慢的病因开展了调查分析。结果显示,采集的270份病虾样本中,对虾肝肠胞虫(Enterocytozoon hepatopenaei,EHP)PCR阳性检出率高达85.19%,传染性皮下及造血器官坏死病毒(infectious hypodermal and hematopoietic necrosis virus,IHHNV)检出率为0;所有采集的病虾样本中也未分离到常见的致病菌;54份正常的对虾样本中EHP和IHHNV均未检出。将病虾PCR扩增产物进行序列测定和比对分析,结果获得的序列片段与Gen Bank中已有EHP相关序列相似性高达99.55%;病虾的肝胰腺组织病理切片观察显示,在虾肝胰腺组织中可观察到处于各个生长发育阶段的EHP。通过上述研究,初步认为EHP是引起舟山地区大棚养殖对虾生长缓慢的一个重要病原。     

Salinity responses of the juvenile penaeid shrimp Penaeus japonicus: II. Free amino acids

The free amino acids (FAA) of juvenile Penaeus japonicus were measured after 48 h of exposure of the shrimps to hypo- and hyperosmotic salinity stress. The concentrations of FAA decreased linearly with decreasing salinity from 50‰ to 10‰. The highest amounts of individual FAA in seawater-adapted P. japonicus are exhibited by glycine (51%), followed by taurine (14%), arginine (10%), proline (9%), and alanine (6%). The main osmoeffectors are glycine, proline, and alanine, which together lower the FAA pool by 80% after a hypoosmotic shock from 40 to 10‰. The concentrations of taurine, arginine, ornithine, and glutamate are not affected by external salinity change. Under hypoosmotic conditions taurine, glutamate, and arginine decrease by only 13–15%, and asparate, ornithine, and lysine by 28–34%. All other amino acids in the FAA pool are reduced by 50 to 88% — the greatest loss is shown by proline (by 96%). Below 25‰ intracellular volume regulation is maintained entirely by proline and glycine, whereas the other FAA concentrations remain more or less constant. After hyperosmotic shock, the concentrations of nearly all FAA increase. This is also true for the essential FAA (+ 86%) — indicating protein hydrolysis. A salinity range between 25 and 40‰ is recommended for the extensive aquaculture of P. japonicus.     

Comparative costs of postlarval production from wild or domesticated Kuruma shrimp, Penaeus japonicus (Bate), broodstock

The present study compares the relative costs of stocking ponds with postlarvae from wild or domesticated Kuruma shrimp, Penaeus japonicus (Bate), broodstock. Wild broodstock were obtained from a commercial trawler. Domesticated broodstock were reared to harvest size (wet weight = 25 g) on a commercial farm and then transferred to controlled environment tanks where they were grown to a final wet weight of 50 g. The costs of stocking ponds with postlarvae were calculated from the observed reproductive output, the costs of purchasing wild broodstock and the costs of domesticated broodstock production in the controlled environment facility. Domesticated P. japonicus spawned comparable numbers of eggs to wild broodstock of similar size, but hatching success was significantly lower. A total of 12 domesticated P. japonicus broodstock would be needed to produce the postlarvae to stock a 1-ha pond, compared to only six wild broodstock. However, the much higher relative costs of wild broodstock means that the cost of using their postlarvae would be Aus$851 per pond compared to Aus$390 for domesticated broodstock. The present authors conclude that the use of domesticated P. japonicus broodstock could be a cost-effective alternative to wild broodstock in Australia and in other countries where P. japonicus is farmed.     

Recent developments of shrimp, Penaeus monodon (Fabricius) and Penaeus merguiensis (de Man), culture in East Java

Shrimp, Penaeus monodon (Fabricius) and Penaeus merguiensis (de Man), culture on East Java is described with special attention to the differences in production characteristics between areas and districts. Traditionally, tambak culture developed along the North coast of East Java where the majority of modern tambaks are still located. The practice never developed extensively on Madura's Island. With the exception of the latter, intensification, startingin 1984-1987, touched all areas. In 1991, the combined production of P monodon and P. merguiensis reached 35 000 Mt, representing a value of US$ 220 × 10⁶. The following year, a decline in total production was noted, mainly caused by a diminished production of intensive farms. Possible causes for this production drop are explored.     

Salinity responses of the juvenile penaeid shrimp Penaeus japonicus: I. Oxygen consumption and estimations of productivity

The oxygen consumption of Penaeus japonicus was measured in relation to low salinity stress and crowding. Within 48 h, Penaeus japonicus shows no mortality in a salinity range of 25–40‰ and a mortality of only 25–30% within a salinity range of 10–55‰. With a change in salinity from 37‰ to 10‰, oxygen consumption increases rapidly to 300% of the initial value and stabilizes at 200% after a few hours. After the initial conditions are restored, oxygen consumption remains raised for at least 6 h. The calculated loss of productivity caused by a reduction of salinity can amount to 33% of total animal weight. Crowding also increases oxygen consumption at a stocking density above 400 postlarval prawns/m². In consequence, a stable environmental salinity range of 30–40‰ and low stocking densities are recommended for extensive aquaculture.     

Impact of yellow head virus outbreaks in the whiteleg shrimp,Penaeus vannamei (Boone), in Thailand

Yellow head virus (YHV) is known as a major pathogen in the black tiger shrimp, Penaeus (Penaeus) monodon. It can also cause serious mortality in farmed whiteleg shrimp, Penaeus (Litopenaeus) vannamei. However, there is no published information on the economic and/or production impact of the disease in P. vannamei. Shrimp with gross signs of YHV disease (faded body colour and 60–70% mortality) were observed in 20 study farms rearing P. vannamei in the central part of Thailand from the end of 2007 through early 2008. The estimated economic loss for these farms according to the Thai Animal Aquaculture Association was approximately US$3 million. Detailed sequence analysis of RT‐PCR amplicons from shrimp in all the study ponds revealed the presence of YHV Type 1b (YHV‐1b) alone (characterized by a 162‐bp deletion in the ORF3 region encoding the structural gene for gp116) and the absence of YHV Type 1a (YHV‐1a), the original YHV type reported from Thailand. Despite the large 162‐bp deletion (= 54 deduced amino acids) in the gp116 structural gene, histopathology of YHV‐1b infections was identical to that of YHV‐1a infections, and electron microscopy revealed that YHV‐1b virions were morphologically indistinguishable from those previously reported for YHV‐1a. In addition, an existing commercial RT‐PCR detection kit and an immunochromatographic test strip for the detection of YHV were proven to have been valid tests for both YHV‐1b and YHV‐1a. The source of the virus for these outbreaks was unlikely to have been the post‐larvae used to stock the ponds, as they were derived from domesticated specific pathogen‐free stocks free of YHV. Thus, it is possible that they originated from an unknown, natural reservoir.     

中国对虾、白虾、蛤仔轮混养技术

蛤仔即菲律宾蛤仔,又称沙蚬子、蚬子、马蚬子,花蛤等。白虾即脊尾白虾,死亡体呈白色或煮熟后除头部红色外,其余部分全部呈白色,故称白虾,是我国特有的一种重要经济虾类。由于它们均肉味鲜美、营养丰富、生长迅速、养殖方法简单、生长周期短、投资少、效益大、所以蛤仔、白虾是我国沿海地区重要的增养殖品种。     

Allozyme genetic analysis in hatchery strains and wild blue shrimp, Penaeus (Litopenaeus) stylirostris (Stimpson), from the Gulf of California

We conducted a population genetic analysis of Penaeus stylirostris to describe the genetic variability in two wild samples (Guaymas and Peñasco) and in two cultivated strains (A and B), and to determine the relationship among samples. Seventeen enzymatic systems and general proteins were used to visualize 31 loci. Of the 31 loci, 11 polymorphic loci (35%) were detected in all the organisms, with an average heterozygosity of 0.10 and an average of 1.8 per locus. There were no significant differences among the four samples of observed heterozygosity or percentage of polymorphic loci. According to Hardy–Weinberg, both cultivated strains showed disequilibrium in more loci than the wild samples. Guaymas showed linkage disequilibrium in five pairs of polymorphic loci, Peñasco samples in two pairs, A in seven pairs, and B in nine pairs. Peñasco and both cultivated lineages showed evidence of recent reductions in their effective populations size. Based on the comparisons of F_st values, and the distribution of the allelic frequencies, the cultivated strains were significantly different from the two wild populations. There is evidence that strain B originated from A and the discrepancies between the strains are probably the result of genetic drift and a founder effect.     

Vibrio bacteria isolated from black tiger shrimp, Penaeus monodon Fabricius

Abstract. Two hundred and five isolates of Vibrio bacteria were obtained from diseased black tiger shrimp, Penaeus monodon Fabricius, cultured in Thailand during the period from February 1988 to January 1990. Ninety-six isolates of the bacteria were identified as Vibrio parahaemolyticus. The others included 74 isolates of V. vulnificus , 18 isolates of V. alginolyticus , six isolates of V. fluvialis and 11 isolates of Vibrio spp. Comparisons of some characteristics of the bacteria studied are given.     

The effectiveness of a commercial microbial product in poorly prepared tiger shrimp, Penaeus monodon (Fabricius), ponds

The efficacy of a commercial microbial product was tested in commercial tiger shrimp, Penaeus monodon (Fabricius), ponds for one culture period in Kuala Selangor, Malaysia. Four ponds with replicates for treatment and control were used. The pond bottom was dried but the organic sludge was not removed as normally practised in pond preparation. The ponds were stocked with 15 post‐larvae at the rate of 31.m^?2. Physical, chemical and biological parameters of the pond were analysed every 2 weeks during the culture period. Water quality parameters remained within the optimum range for shrimp culture except for ammonia‐nitrogen being significantly higher in control ponds and silica in treated ponds. Benthic organisms were not found in any of the ponds. The average counts of different bacteria were not significantly higher in treated ponds than control. Because of poor health, the shrimp were harvested earlier (72 days) than the usual 120 days. An average of 875.60 ± 67.00 kg shrimp ha^?1 was obtained in treated ponds with a feed conversion ratio (FCR) of 1.57 ± 0.10 and survival rate of 42.35 ± 5.37% compared with 719.50 ± 130.94 kg shrimp ha^?1, 2.99 ± 0.70 and 21.25 ± 3.26%, respectively, in control ponds. Neither the microbial product nor the frequent water exchange was effective in overcoming the problems caused by the poor pond bottom.