IJA Volume 59, Issue 1, 2007

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    Experimental commercial growout of Penaeus semisu/catus (Decapoda: Penaeidae)
    (Israeli Journal of Aquaculture - BAMIGDEH, 2007) Turkmen, Gurel
    Sea bass and sea bream have become almost synonymous with marine aquaculture in Turkey, indicating the level of commercial success they have attained during the last two decades. However, to diversify an industry overly dependent on these two products, as well as to provide the market with an additional commodity, other species are being considered for future culture. In the present study, commercial culture of Penaeus semisulcatus on the Aegean coast of Turkey was evaluated. In 150 days, the shrimp grew from 0.03 g to 18.72 g, with a mean daily growth rate of 0.125 g. The food conversion rate and specific growth rate were 2.26 and 2.34, respectively. Production reached the equivalent of 2880 kg/ha with a survival of 77%. While pro- duction results and shrimp weights were considerable, to obtain larger shrimp of greater value, early maturation and spawning in a nursery system must be included in conjunction with the growout ponds.
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    Impact of water temperature on growth in cobia, Rachycentron canadum, cultured in cages
    (Israeli Journal of Aquaculture - BAMIGDEH, 2007) Vu, Shyi-Liang; Ueng, Ping-Sheng
    Temperature is a major factor affecting fish growth in natural environments. The relationship between water temperature and growth rate in cobia, Rachycentron canadum, was examined at a fish farm in Penghu, Taiwan. Six cages, stocked with 300 fish each, were used in the year-long experiment. Growth rate was monitored by sampling 30 fish from each cage every month. Water quality was optimum throughout the experiment. Fish were fed commercial fish food to satiation twice a day. Cobia grew 0.84%/day in summer (March-September) and 0.41%/day in winter (October-February). The slowest growth occurred in late December at temperatures of 15.0- 16.5°C and the fastest during summer at temperatures above 28°C.
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    Impact of planting season on growth and survival of the carpet shell clam (Tapes clecussatus, Linnaeus 1758)
    (Israeli Journal of Aquaculture - BAMIGDEH, 2007) Serdar, S.; Lok, A.
    The growth and survival of juvenile carpet shell clams, Tapes decussatus, planted in autumn (October-April) and spring (April-October) in Sufa Lagoon near Izmir, Turkey, were compared. Clams of 20.39±0.24 mm were sown in October (Group I) and clams of 20.43±0.23 mm were sown in April (Group II). Seedlings were sown in plastic boxes at a density of 160 clam/m2. Temperature ranged 8-32oC, salinity 38-43‰, and chlorophyll a 4.04-30.93 μg/l. In six months, the clams in Group I reached 23.16 mm while the clams in Group II reached 24.02 mm (p<0.05). Survival was 80% in Group I and 77.5% in Group II (p>0.05).
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    Isolation, characterization, and sequencing of nodavirus in sturgeon (Acipenser gueldestaedi L.) reared in freshwater facilities
    (Israeli Journal of Aquaculture - BAMIGDEH, 2007) Xylouri, Eftychia; Kotzamanis, Yannis R.; Athanassopoulou, Fotini; Dong, Li; Pappas, Loanis S.; Argyrokastritis, Alexandros; Fragkiadaki, Eirini
    The study demonstrates the presence of a nodavirus that affected sturgeon in fresh water, caus- ing disease with neurological signs. The virus was isolated and inoculated onto SSN-1 (striped snakehead, Channa striatus) cell cultures where cytopathic effects (CPE) of the virus included vacuolation of the cells and degeneration of the monolayer. A 255 bp amplicon from nucleic acid preparations of brain tissue from infected sturgeon was detected by PCR (RT-PCR and nested- PCR) and compared with corresponding amino acid sequences of other infected species. The sequences from the sturgeon were similar to those of sea bass, red spotted grouper, and European eel, supporting the hypothesis that the virus originated in marine fish and was hori- zontally transmitted to freshwater sturgeon.
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    Effects of dietary androstenedione concentration on growth of tilapia fry (Oreochromis aureus Linnaeus)
    (Israeli Journal of Aquaculture - BAMIGDEH, 2007) Turan, Funda; Gurlek, Mevlut; Turan, Cemal
    The effects of androstenedione on the growth, body composition, and survival of tilapia (Oreochromis aureus) fry were examined. Diets were supplemented by one of three androstene- dione concentrations (50, 100, or 200 mg/kg) for twelve weeks. The growth rate significantly increased in fish fed 50 mg androstenedione per kg compared to the control (p<0.01) but decreased dramatically at concentrations beyond 50 mg/kg. The specific growth rate, protein efficiency ratio, and food conversion ratio were significantly better in the 50 mg/kg group than in the other groups. Crude protein and survival at all androstenedione levels did not significantly differ from those of the control but lipid content dropped with 100 mg/kg supplementation.
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    Prevalence and intensity of ectoparasites in rainbow trout (Oncorhynchus mykiss) from larvae stage to market size in Turkey
    (Israeli Journal of Aquaculture - BAMIGDEH, 2007) Ogut, Hamdi; Akyol, Abdurrezzak
    Rainbow trout (Oncorhynchus mykiss) from three Turkish farms were sampled monthly from May 2003 to June 2004 to determine ectoparasite seasonality, prevalence, and intensity. Smears of gills, skin, and fins of 1260 larvae to market-size fish were examined. Six protozoans and one monogenean were found: Ichthyobodo necator, Chilodonella piscicola, Ichthyophthirius multifil- iis, Gyrodactylus sp., Trichodina claviformis, Apiosoma piscicolumn, and Hexamita salmonis. The first three were found mainly in fry and all except I. multifiliis occurred in low temperatures from late fall through early spring. Infections of C. piscicola and Gyrodactylus sp. were persis- tent and T. claviformis was found for the first time on rainbow trout in the area.
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    Effects of dietary protein and lipid levels on growth and body composition of silver dollar (Metynnis schreitmuellerei) fry
    (Israeli Journal of Aquaculture - BAMIGDEH, 2007) Singh, R.K.; Vartak, V.R.; Balange, A.K.
    The aims of this study were to determine the effects of different levels of protein and lipid on the growth and body composition of fry of the silver dollar, Metynnis schreitmuelleri (Ahl). The fry were first fed diets containing 25, 35, 45, or 55% protein to determine the optimum protein level. The best growth, body composition, protein efficiency ratio, and food conversion ratio were obtained with the 35% protein diet. The fry were next fed diets containing 35% protein and 0, 3, 6, 9, or 12% lipid. The best growth, body composition, protein efficiency ratio, and food conver- sion ratio occurred with the diet containing 35% protein and 6% lipid.
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    Effects of dietary mannan oligosaccharides (MOS) on growth, body composition, and intestine and liver histology of the hybrid tilapia (Oreochromis niloticus x 0. aureus)
    (Israeli Journal of Aquaculture - BAMIGDEH, 2007) Ayce Genc, M.; Yilmaz, Erdal; Genc, Ercument; Genc, Ercument; Aktas, Mevlut
    This is the first study on the effects of dietary mannan oligosaccharides (MOS) on growth, body composition, and intestine and liver histology of hybrid tilapia (Oreochromis niloticus x O. aureus). Experimental diets were prepared from commercial trout diet, supplemented with MOS at levels of 0, 1.5, 3.0, or 4.5 g MOS/kg feed and randomly assigned to triplicate groups. At the end of the trial, there were no significant differences between treatment groups (p>0.05) in growth parameters (live weight gain, specific growth rate, feed conversion ratio, protein efficien- cy ratio) or body indices (hepatosomatic and viscerosomatic). Dry matter and protein contents increased with increasing rates of dietary MOS (p<0.05) while the mean villi length of fish fed the diet containing 1.5‰ MOS was significantly longer (p<0.05) than that of the fish fed 4.5‰ dietary MOS. The different levels of dietary MOS had no detrimental effects on liver tissue or general fish health.
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    First incidence of clinical signs of nodavirus infection in sea bream, Sparus auratus L
    (Israeli Journal of Aquaculture - BAMIGDEH, 2007) Bitchava, Konstantina; Xylouri, Eftychia; Fragkiadaki, Eirini; Athanassopoulou,; Papanastassopoulou, Maria; Sabatakou, Olga
    The causal agent of viral encephalopathy and retinopathy in fish is an RNA virus known as nodavirus, a member of the Nodaviridae family. According to published data, sea bream (Sparus aurata L.) that are infected with the virus show no clinical signs and are considered an asympto- matic carrier. In this paper we report for the first time a clinical case of nodavirus in commercially reared sea bream. Fish with clinical signs underwent necropsy and routine microbiological, para- sitological, and histopathological examination. The virus was detected by RT-PCR and isolated in SSN-1 cell cultures. The results described in this study demonstrate the presence of a nodavirus agent that can infect sea bream in sea water, causing a disease similar to that observed in marine sea bass but with lower mortality and milder neurological signs. Histopathological lesions were also similar to those observed in sea bass infected with nodavirus.