IJA Volume 58, Issue 1, 2006

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    Authentication of fish species using a simple PCR-RFLP method
    (Israeli Journal of Aquaculture - BAMIGDEH, 2006) Hisar, Oicay ; Erdogan, Orhan ; Aksakal, Ecrument ; Hisar, Sükriye Aras
    A polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was developed as a tool to prevent commercial frauds in fish products. The PCR was used to ampli- fy the cytochrome b gene, part of the mitochondrial genome. The PCR products were digested with different restriction endonucleases (AluI, HaeIII, HinfI, Hsp92, Taql) to identify five fish species - Mugil cephalus, Pomatomus saltator, Belone belone, Merlangius merlangus, and Oncorhynchus mykiss. None of the tested enzymes, alone, was able to distinguish between the five fish species, but by combining the results of two digestions, all five species could be differ- entiated. Thus, this method can be used to expose fraudulent substitutions with less valuable fish.
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    Growth and survival rates of bearded horse mussel (Modiolus barbatus Linne, 1758) in Mersin Bay (Turkey)
    (Israeli Journal of Aquaculture - BAMIGDEH, 2006) Lok, A. ; Acarli, S. ; Serdar, S. ; Koss, A. ; Goulletquer, P.
    The growth and survival rates of four size classes (10, 15, 20, and 25 mm) of bearded horse mussels (Modiolus barbatus) grown in net bags in Mersin Bay, Izmir, were assessed from May 2001 to May 2002. Temperature ranged 14-23°C, average chlorophyll a was 3.34±0.35 μg/l, average total particulate matter 12.43±0.68 mg/l, and average particulate organic carbon 210.23±18.00 μg/l. Shell lengths increased 23.05, 19.76, 19.40, and 12.09 mm in the four class- es (from small to large) and live weights increased 13.21, 10.46, 10.06, and 4.96 g, respective- ly. Survival rates ranged from 25% in the smallest size class to 87.5% in the 20 mm class (p<0.05). Mussels grew significantly fastest in the smallest size class (p<0.05).
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    Anesthetic effects of clove oil during handling and transportation of the freshwater prawn, Macrobrachium rosenbergii (de man)
    (Israeli Journal of Aquaculture - BAMIGDEH, 2006) Vartak, Vivek ; Singh, Ravendra Kumar
    The present work was conducted to determine the effects of clove oil as an anesthetic on post- larvae (mean length 13.42±0.84 mm) and juveniles (43.57±0.94 mm) of the giant freshwater prawn, Macrobrachium rosenbergii. In the first of three experiments, exposure to ethanol for 15 min was ineffective in tranquilizing the freshwater prawns at concentrations of 75-625 mg/l for postlarvae and 375-5,000 mg/l for juveniles, indicating that ethanol could be used as a solvent for clove oil without contributing to any anesthetic reaction. In the second experiment, prawns were exposed to one of six clove oil concentrations for 15 min (15-125 mg/l for postlarvae; 75- 1,000 mg/l for juveniles). For postlarvae, the fastest induction (0.90±0.05 min) was achieved at the highest concentration (125 mg/l) but all prawns in this treatment died. Induction and recov- ery times in concentrations of 30, 45, and 60 mg/l were all under 15 min. At 75 mg/l, postlarvae were tranquilized in a relatively short period (3.30±0.10 min) and recovery time was maximum (45.17±0.20 min). For juvenile prawns, concentrations of 750 mg/l and up were fatal while 125 and 250 mg/l induced anesthesia in 78.30±0.20 and 66.83±0.18 min, respectively, with recovery in 4.21±0.12 and 16.91±0.16 min. As far as induction and recovery times are concerned, clove oil was a suitable anesthetic only for postlarvae. The third experiment revealed that a concen- tration of 15 mg/l could safely be used to transport postlarvae up to three hours.
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    Filtration and ingestion rates of the rotifer Brachionus plicatilis fed five species of microalgae at different cell densities
    (Israeli Journal of Aquaculture - BAMIGDEH, 2006) Savaş, Sevgi ; Güçlü, Zekiye
    The microalgae Tetraselmis suecica, Nannochloropsis oculata, Chlorella sp., Isochrysis gal- bana, and Dunaliella tertiolecta were used as food for the rotifer Brachionus plicatilis (L type) raised in laboratory conditions at 25±1oC and 25‰ salinity. Filtration and ingestion rates of the rotifer were determined to study the effects of different microalgae densities and feeding times on the feeding behavior of the starved B. plicatilis. The highest filtration (11.5 x 10-4 ml/ind/min) and ingestion (246.99 x 102 cells/ind/min) rates were obtained with N. oculata. The filtration rates dropped when the microalgae density rose beyond the optimum level, but ingestion rates varied with algae species. Feeding time significantly influenced these rates: after 60 min, both rates dropped.
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    Improvement of growth performance in tilapia (Orepochrimis aureus Linnaeus) by supplementation of red clover Trifolium pratense in diets
    (Israeli Journal of Aquaculture - BAMIGDEH, 2006) Turan, Funda
    This study was conducted to investigate the effects of red clover on growth, body composition, and survival of tilapia, Oreochromis aureus. Three concentrations of dietary red clover (50, 100, 200 mg/kg) were tested for 90 days. The growth rate was significantly better in fish fed 100 mg red clover/kg feed than in the control that contained no red clover (p<0.01). The specific growth rate ranged from 3.79±0.10 in the 200 mg/kg red clover treatment to 4.41±0.05 in the 100 mg/kg treatment. The food conversion ratio, protein efficiency ratio, and apparent net protein utilization were significantly highest in groups fed the 100 mg red clover/kg diet (p<0.01). Survival in groups fed red clover did not differ from that of the control. The highest protein content (19.74%) was obtained in the 100 mg/kg group and it was significantly higher than in all other groups (p<0.05). Moisture and ash contents did not differ among treatments. Lipid content was not significantly affected by red clover dosage. The findings of the present study suggest that 100 mg red clover/kg feed improves the growth rate and feed utilization of tilapia.
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    Moisture, protein, and amino acid contents of three freshwater zooplankton used as feed for aquacultured larvae and postlarvae
    (Israeli Journal of Aquaculture - BAMIGDEH, 2006) Ovie, Solomon I. ; Ovie, Stella O.
    The moisture content, crude protein level, and amino acid profile of three freshwater zooplank- ton (Moina micrura, Diaphanosoma excisum, Brachionus calyciflorus) commonly used for rear- ing fish larvae were analyzed using standard methods. The moisture contents and crude protein levels were similar, as follows: M. micrura 89% and 52.4%, D. excisum 89.3% and 57.3%, and B. calyciflorus 91.6% and 50.3%, respectively. The samples contained 17 amino acids: nine essential and eight non-essential amino acids. The dominant essential amino acids (per 16 g N) in M. micrura were lysine (10.73 g), arginine (8.17 g), leucine (8.0 g), and histidine (5.09 g); in D. excisum, lysine (9.95 g), leucine (8.0 g), valine (6.23 g), and arginine (4.78 g), and in B. caly- ciflorus, leucine (8.95 g), lysine (8.64 g), arginine (6.37 g), phenylalanine (5.20 g), and valine (4.83 g). In all three species, glutamine and aspartic acid dominated the non-essential amino acid profile, and methionine was the essential amino acid in the smallest concentration. Differences among amino acid profiles were insignificant (p>0.05).
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    Exotic species in global aquaculture - a review
    (Israeli Journal of Aquaculture - BAMIGDEH, 2006) Shelton, William L. ; Rothbard, Shmuel
    The culture of exotic fishes contributes about 17% to global food aquaculture production. Transplanted native species add substantially to the aquatic harvest of food and sport fishes in many countries. Some countries are very dependent on the cultivation of non-native species; yields of exotics exceed 25% of the total harvest in China, 60% of the freshwater harvest in the Philippines, and 50% of the production in Brazil. Aquatic food production in Israel is predomi- nately from introduced fishes. In the USA, transplanted species are economically important as food and sport fish and exotics are used in resource management as well as a major food source. Countries of origin for globally important fishes include China (endemic carps), USA (Atlantic salmon and rainbow trout), Europe (common carp), and Africa (tilapias). The aquacul- ture production of food fish will become increasingly vital as oceanic capture fisheries continue to stagnate. Exotic and transplanted fishes that are widespread today will represent a greater proportion of future aquaculture production because technology for their culture is already well known and can readily be applied, and because these species are more easily domesticated and genetically improved.