IJA Volume 56, Issue 1, 2004
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ItemChanges In Blood Ion Levels And Mortality Rates In Different Sized Rainbow Trout (Oncorhychus Mykiss) Following Direct Transfer To Sea Water(Israeli Journal of Aquaculture - BAMIGDEH, 2004)Plasma ion values and mortality rates were compared for 450 rainbow trout (Oncorhynchus mykiss) of three sizes following direct transfer from fresh water to Black Sea water of about 18 ppt. In fish of 14.29±0.30 g, plasma Na+, Cl- and K+ levels significantly (p<0.05) rose above ini- tial values five days after the transfer and peaked at 178.6±5.66, 153.9±0.14 and 1.14±0.04 mM/l, respectively. In 20.45±0.48 g fish, these values also rose significantly, reaching 172.4±4.24, 151.8±6.65 and 0.98±0.04 mM/l by day 5. In fish of 29.91±0.99 g, however, plasma Na+ and Cl- concentrations peaked 19 days after transfer, reaching only 165.5±6.43 and 142.9±8.34 mM/l, while plasma K+ reached its highest concentration of 1.02±0.06 mM/l on day 12, All three concentrations dropped to near initial values on day 26. In all groups, the plasma Ca2+ level rose significantly (p<0.05) above the initial value five days after transfer and then declined while the plasma P5+ concentration dropped on day 5, reaching a minimum on day 12 and recovering the initial level on day 26. The lowest mortality (8.0±1.89%) was recorded in the 30 g group, followed by 19.3±0.94% and 24.7±0.94% in the 20 g and 14 g groups. The failure of the smallest fish to adapt after direct transfer to sea water was likely due to excessively high plasma Na+ and Cl- concentrations and tissue dehydration, indicating that fish of 30 g best adapt to a seawater environment of 18 ppt.
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ItemClearance Rates Of Suspended Particulate Organic Carbon By Nile Tilapia With A Dual Pattern Of Filter Feeding(Israeli Journal of Aquaculture - BAMIGDEH, 2004)The filter-feeding activity of Nile tilapia, Oreochromis niloticus L., was observed during a 24-h feeding cycle for five consecutive days. The feeding activity was high from afternoon to midnight, with a peak after dusk, and lowest from midnight to morning. The clearance rate of cyanobacte- ria dominated water was estimated during the low morning and high evening feeding periods. The tilapia cleared 34 mg C/l suspended particulate organic carbon in 4.5 h during the reduced morning period (beginning 07:00) and 45 mg C/l in 1 h during the peak evening period (begin- ning 20:30). Clearance rates of the cyanobacterial water were 13.4±1.2 l/kg fish/h in the morn- ing and 66±3.6 l/kg fish/h in the evening.
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ItemEffects Of Dichlorvos And Characterization Of Microsomal Nadph-Cytochrome P450 And NADH-ferricyanide Reductase In Rainbow Trout (Oncorhynchus Mykiss) Liver(Israeli Journal of Aquaculture - BAMIGDEH, 2004)The kinetics of oxidation of rainbow trout (Oncorhynchus mykiss) NADPH-cytochrome P450 reductase (NCPR) by cytochrome-c and NADH-ferricyanide reductase (NFR) by K3Fe(CN)6 were studied. NCPR and NFR activities from liver microsomes of rainbow trout (Oncorhynchus mykiss) had a specific activity of 0.0246 and 0.0350 nmoles/min/mg protein, respectively. The maximal rate of NCPR reaction was found at cytochrome-c concentrations above 2.1 mM and in the presence of cyt c. Vmax and Km were 0.0083 nmoles/min/mg and 1.14 mM. The maximal rate of NFR reaction was at K3Fe(CN)6 concentrations higher than 2.0 mM and in the presence of K3Fe(CN)6. Vmax and Km values were 1.04 nmoles/min/mg and 0.352 mM, respectively. The inhi- bition by dichlorvos (DDVP) on NCPR and NFR activity was not exhibited over the range 1.0-5.0 mM DDVP.
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ItemEffect Of Dietary Olive Pomace Oil And L-Carnitine On Growth And Chemical Composition Of African Catfish, Clarias Gariepinus (Burchell, 1822)(Israeli Journal of Aquaculture - BAMIGDEH, 2004)The effects of dietary olive pomace oil and L-carnitine on growth performance, body indices and chemical composition of African catfish, Clarias gariepinus, were investigated. A 3x2 factorial design was used by offering diets having three different energy/protein ratios and supplemental L-carnitine at either 0 or 2000 mg/kg diet. Ten juvenile African catfish (12 g/fish) were stocked into 80-l glass aquaria and fed an experimental diet for seven weeks. The L-carnitine supple- mentation did not affect body indices. However, growth and chemical composition were influ- enced by both dietary lipid and L-carnitine. The increase in muscle lipid was greater than in the liver for all treatments. Fish fed the high energy diet (9% olive pomace oil) had a low appetite and feed intake, while fish fed the low energy diet (3% olive pomace oil) and supplemental L- carnitine had better feed intake and growth. On the other hand, fish fed the high energy diet (9% olive pomace oil) with or without L-carnitine had better feed conversion.
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ItemCarbohydrases In The Alimentary Canal And Associated Organs Of The African Snakehead, Parachanna Africans (Osteichthyes: Channidae)(Israeli Journal of Aquaculture - BAMIGDEH, 2004)Standard qualitative and quantitative methods were employed to determine the presence and activity of digestive carbohydrases in different regions of the alimentary canal and associated organs of the African snakehead, Parachanna africans. Qualitatively, amylase, maltase, sucrase, and lactase were present in the stomach, pyloric ceca, anterior and posterior intestine, liver and spleen. No carbohydrases were found in the esophagus whereas cellulase was com- pletely absent throughout the canal and organs. Quantitatively, a relatively large amount of lac- tase and maltase was found throughout the canal and organs (except the esophagus) while sucrase was active in varying degrees in all the canal regions and associated organs (except the esophagus).
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ItemEffects Of Land-Based Trout Farms On The Benthis Macroinvertebrate Community In A Turkish Brook(Israeli Journal of Aquaculture - BAMIGDEH, 2004)Benthic macroinvertebrates and physico-chemical parameters were surveyed at the source of the Karasu Brook in Bozüyük, Bilecik Province, Turkey, and at the inlets and outlets of five rainbow trout farms that use the brook water and discharge effluents into it. The dissolved oxygen, pH, ammonia-nitrogen, nitrite-nitrogen, nitrate-nitrogen and total phosphorus in the farm effluents were within effluent standards for trout farming in different countries. The macroinvertebrate community in the brook consisted of Mollusca, Gastropoda (Physidae, Limnaedae, Planorbidae, Neritidae), Bivalvia (Spharidae), Annelidae, Oligochaeta (Tubificidae), Hirudinea (Glos- siphonidae, Erpobdellidae), Arthropoda, Insecta (Chironomidae, Ephemerellidae) and Crustacea (Gammaridae, Asellidae). Tubificidae and Chironomidae were generally observed in all sampling stations; the highest abundance was in the inlets and outlets of the two farms nearest the source. The most common measures of biodiversity, i.e., richness, Simpson’s index, Shannon-Wiener index and evenness, were used during the year-long study.
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ItemLive And Inert Foods For Postlarvae Of The Giant Freshwater Prawn Macrobrachium Rosenbergll(Israeli Journal of Aquaculture - BAMIGDEH, 2004)Five live or inert food organisms (adult Artemia, Moina, Tubifex worms, clam meat, poultry egg custard) were evaluated as feed for postlarvae of Macrobrachium rosenbergii. The postlarvae (avg 5.2±0.22 mg, 7.2±0.38 mm) were reared in plastic pools (0.9 m diameter x 0.6 m) contain- ing 100 l fresh water, stocked at one postlarva per liter for 30 days, with five replicates of each treatment. There were significant differences (p<005) in final weight gains of the postlarvae (62.94-88.86 mg), final length gains (16.45-20.71 mm) and survival (69.67-92.33%). The live Moina were superior to the other foods with a significantly higher weight gain (1708.92±54.03%), length gain (287.70±4.76%) and specific growth rate (9.45±0.1%/d). The higher protein (66.16%) and n-3 HUFA (10.20%) levels in Moina may explain these results.
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ItemEffect Of Anesthetics On Stress And The Innate Immune System Of Gilthead Seabream (Sparus Surata)(Israeli Journal of Aquaculture - BAMIGDEH, 2004)Anesthesia may depress the immune system in mammals and fish. In the present work, two anesthetics used in aquaculture, clove oil (0.445 mM) and benzocaine (0.225 mM), were tested to observe their effects on the stress response and innate immune system activity of gilthead seabream (Sparus aurata L.). Results showed that both anesthetics induced increased blood glucose and serum cortisol levels. In addition, benzocaine depressed lysozyme activity, produc- tion of reactive oxygen species and pinocytosis activity. These were not depressed by clove oil, suggesting that clove oil is a safer anesthetic for seabream as it does not cause immunode- pression in anesthetized fish.