IJA Volume 60, Issue 2, 2008

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    Activity of the Digestive Protease, Chymotrypsin, in Larvae of the Cultured Sharpsnout Sea Bream (Diplodus puntazzo)
    (Israeli Journal of Aquaculture - BAMIGDEH, 2008) Aktulun, Sevim ; Süzer, Cüneyt ; Kamaci, H. Okan ; Coban, Deniz ; Saka, Sahin ; Firat, Kursat
    Specific and total activity of the digestive protease, chymotrypsin, was studied in cultured sharp- snout sea bream larvae (Diplodus puntazzo) for 35 days from hatching and in a variety of pH lev- els. Activity was detected upon hatching (2.8±0.34 mm total length), before the onset of exoge- nous feeding. Specific chymotrypsin activity exponentially increased from mouth opening on day 3 until day 25, then dropped until the end of the experiment. Total chymotrypsin activity sharply increased to day 10, then continued to increase, but slightly, until the end of the experiment. As expected, pH strongly affected both specific and total chymotryptic activity in the digestive tracts of larvae. Both were significantly lower when pH was acidic (1.5, 3.0, 4.0) than when it was alka- line (8.0, 9.0, 10.0) although there were no significant differences within either the acidic or the alkaline range. Our results indicate that chymotrypsin activity is capable of digesting protein before mouth opening and may be a valuable tool for better understanding the nutritional capa- bilities of young larvae.
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    Dietary Ascorbic Acid Requirements of Fingerlings of Genetically Improved Rohu (Labeo rohita Ham)
    (Israeli Journal of Aquaculture - BAMIGDEH, 2008) Sahoo, Minakshi ; Mukhopadhyay, P.K.
    Indian major carp, including Labeo rohita, are incapable of biosynthesizing ascorbic acid due to the absence of the enzyme L-gulono-γ-lactone oxidase. To assess their ascorbic acid require- ments, improved rohu fingerlings (2.33±0.18 g) were fed one of six semi-purified formulated diets containing 0, 20, 40, 60, 80, or 100 mg ascorbyl-2-polyphosphate (APP) per kg feed for 60 days in water of 28-30°C. Fish fed diets deficient in ascorbic acid had a significantly lower weight gain, poor feed conversion (FCR) and protein efficiency (PER) ratios, lower survival, and behavioral abnormalities such as lethargic movements and poor feed intake. The best FCR and PER were recorded in the 60 mg APP diet. Ascorbic acid in the kidney dropped from 36.62 to 5.09 mg/kg by the end of the experiment. Weight gain analysis by regression indicated that the dietary ascor- bic acid requirement for maximum growth and survival of rohu fingerlings can be achieved with 53.5 mg APP incorporated into 1 kg diet.
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    Population Growth of the Freshwater Cladoceran, Diaphanosoma excisum, Fed Different Densities of the Alga, Scenedesmus acuminatus
    (Israeli Journal of Aquaculture - BAMIGDEH, 2008) Ovie, Solomon I. ; Ovie, Stella O.
    The freshwater cladoceran, Diaphanosoma excisum Sars 1885, was fed the micro-alga Scenedesmus acuminatus, at one of six densities (0.5, 1.0, 1.5, 2.0, 3.0, or 4.0 x 106 cells/ml) in 40-l glass aquaria. The D. excisum density increased as the Scenedesmus density increased to 1.5 x 106 cells/ml, in which it peaked at 7345 individuals per liter. Population growth was inhibit- ed at higher algae densities. The percent of egg-bearing females and the number of eggs per egg-bearing female followed a similar pattern. Production of approximately 7000 individuals per liter was encouraging from a mass production point of view and indicates that S. acuminatus is suitable for use as a live starter feed for D. excisum which, in turn, is a live feed for larvae of induced-breeding in fish hatcheries.
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    Ontogeny of Fertilized Eggs and Yolk Sac Larvae of Sea Bass (Dicentrarchus labrax)
    (Israeli Journal of Aquaculture - BAMIGDEH, 2008) Naz, Mehmat
    The biochemical compositions of fertilized eggs, yolk sac larvae, and larvae at the beginning of exogenous feeding of sea bass (Dicentrarchus labrax) were determined. Eggs and yolk sac lar- vae contain more monounsaturated and polyunsaturated fatty acids than saturated fatty acids. Essential and non-essential amino acid contents tended to drop at hatching, then sharply increase by the end of endogenous feeding. Amylase and trypsin activity was detected in fertil- ized eggs. Trypsin activity peaked at the beginning of exogenous feeding. The alkaline phos- phatase activity was lowest in fertilized eggs, higher at hatching, and highest at the end of the experiment. Leucine alanine peptidase activity was higher than other enzymatic activity in all three stages. Aminopeptidase N activity increased until hatching, then stabilized until the begin- ning of exogenous feeding.
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    Effect of Betaine as a Feed Attractant on Growth, Survival, and Feed Utilization in Fingerlings of the Indian Major Carp, Labeo rohita
    (Israeli Journal of Aquaculture - BAMIGDEH, 2008) Shankar, R. ; Murthy, Shivananda ; Pavadi, Prakash ; Thanuja, K.
    The study evaluated the efficiency of betaine as a feed attractant on growth, survival, and feed utilization in fingerlings of rohu (Labeo rohita). Betaine was incorporated at 0 (control), 0.25%, 0.50%, or 0.75% in a 30% protein diet and fed to fingerlings for 120 days in a closed and aerat- ed recirculating system. Feed was offered twice daily at a rate of 5% of the fish biomass during the first 15 days and 3% afterwards. Significantly better growth, specific growth rate, survival, food conversion ratio, and protein efficiency ratio were obtained in the group fed 0.25% betaine.
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    Analysis and Characterization of Expressed Sequence Tag (EST) and Simple Sequence Repeats (SSR) from Red Sea Bream, Chrysophrys major, and Gilthead Sea Bream, Sparus aurata
    (Israeli Journal of Aquaculture - BAMIGDEH, 2008) Liu, Yun-Guo ; Chen, Song-Lin ; Liu, Chun-Ying ; Li, Fang-Zheng
    A total of 101 and 119 simple sequence repeats (SSR) were obtained from expressed sequence tags (EST) of the red sea bream (Chrysophrys major) and gilthead sea bream (Sparus aurata), respectively. Dimeric repeats were the most abundant class of SSR in both red (70.30%) and gilthead (51.26%) sea bream. Trimeric, tetrameric, and pentameric repeats occurred in decreas- ing proportions, i.e., 21.36%, 6.8%, and 0.97% in red sea bream and 45.38%, 3.36%, and 0 in gilthead. There were no hexameric repeats in EST of either species. The frequency of every class of SSR (dimeric, trimeric, tetrameric, and pentameric) decreased with increasing repeat length. In cross-species amplification of 20 existing microsatellite loci from gilthead sea bream in 20 red sea bream specimens, twelve loci showed positive amplification and four loci showed polymorphic amplification with two or three alleles.
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    Effect of Dietary Vitamin E on Growth, Fecundity, and Leukocyte Count in Goldfish (Carassius auratus)
    (Israeli Journal of Aquaculture - BAMIGDEH, 2008) James, Raja ; Vasudhevan, Iyyadurai ; Sampath, Kunchitham
    The effects of different levels of dietary vitamin E (0, 100, 200, 300, and 600 mg/kg diet) on growth, gonad weight, fecundity, and leukocyte count were studied in goldfish (Carassius aura- tus) for 120 days. Fish fed the 300 mg vitamin E/kg diet had the best feeding rate, weight gain, and specific growth rate. Fish fed the control diet lacking vitamin E began to develop gonads on day 60 and spawned only once, while those fed diets containing vitamin E began to develop gonads on day 40 and spawned twice. Females fed the 300 mg vitamin E/kg diet had signifi- cantly (p<0.01) heavier gonads and a higher number of eggs with better hatchability than those fed other diets. The second spawn was significantly (p<0.01) more prolific than the first in all groups. Egg weight and diameter and larvae weight and length were significantly (p<0.05) high- er in fish fed 300 mg vitamin E than in fish fed the control diet but did not differ from other vita- min E treatments. Lymphocyte and monocyte populations were highest in fish fed 300 mg vita- min E. Thus, 300 mg vitamin E/ kg diet is the optimum level for improving reproduction and immune response in C. auratus. The probable mechanism for the action of vitamin E on growth and reproduction is discussed.
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    Effects of Probiotics and Spirulina on Survival and Growth of Juvenile Common Carp (Cyprinus carpio)
    (Israeli Journal of Aquaculture - BAMIGDEH, 2008) Ramakrishnan, C. Muthu ; Haniffa, M.A. ; Manohar, M. ; Dhanaraj, M. ; Arockiaraj, A. Jesu ; Arunsingh, S.V.
    A 45-day feeding trial was conducted to investigate the effects of probiotics and spirulina on sur- vival, growth, feed conversion ratio (FCR), protein efficiency ratio (PER), and total heterotroph- ic microbial count in common carp (Cyprinus carpio). Two probiotic organisms (the bacteria Lactobacillus acidophilus and the yeast Saccharomyces cerevisiae) and a single cell protein (Spirulina maximus) were incorporated into diets at concentrations of 1%, 2%, or 3%. The con- trol diet contained no supplement. Spirulina maximus at 3% produced the best and statistically significant (p<0.05) survival, growth (3.69±0.10 g), specific growth rate (1.27±0.02%/d), FCR (0.71±0.08), and PER (1.96±0.03). In general, L. acidophilus produced better growth than S. cerevisiae. The highest FCR (1.93±0.05) was obtained in the control. The total heterotrophic microbial count was highest in S. cerevisiae treatments, followed by L. acidophilus and S. max- imus. The present investigation shows that incorporation of a probiotic or spirulina in diets for common carp results in increased growth rate.
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    Determining Variability, Confidence, and Statistical Power in Aquaculture Experiments
    (Israeli Journal of Aquaculture - BAMIGDEH, 2008) Araujo, Pedro
    This article deals with the lack of appreciation among marine biologists of basic statistics in aqua- culture experiments. Topics include calculation of sources of variation, the importance of true replication rather than pseudo-replication to test for treatment effects, estimation and visualization of the confidence of an experimental design used in feeding trials, and calculation of its statisti- cal power. An arbitrary example is used to illustrate how the described theory can be applied in practice. The approach demonstrates that nutritional experiments with a reduced number of tanks can be a valid strategy as long as certain experimental considerations are taken into account. In addition, it shows that information on the relative sizes of ‘between’ and ‘within’ sources of vari- ation can be used to design more efficient experiments by minimizing the effects of the stronger sources of variance. The approaches used in this article are applicable to large and small-scale experiments.
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    Characterization of Vibrio alginolyticus Isolates from Diseased Cultured Gilthead Sea Bream, Sparus aurata
    (Israeli Journal of Aquaculture - BAMIGDEH, 2008) Akayli, T. ; Timur, G. ; Aydemir, B. ; Kiziler, A.R. ; Coskun, O. ; Albayrak, G. ; Arican, E.
    Biochemical, pathogenical, antigenical, and molecular characteristics of Vibrio alginolyticus iso- lates from diseased cultured gilthead sea bream juveniles (4 and 20 g) were determined by lab- oratory challenge experiments. Intraperitonal challenge resulted in development of the disease but immersion did not. Electrophoresis of outer membrane protein (OMP) and lipopolysaccha- rides (LPS) was performed using sodium dodecyl sulphate poly-acrylamide gel electrophoresis (SDS-PAGE). Molecular typing of Vibrio isolates was conducted using random amplification of polymorphic DNA (RAPD). According to SDS-PAGE of surface antigens of the isolates, profiles of both OMP and LPS were heterogeneous. According to RAPD, isolated bacteria varied genet- ically. The findings reveal differences among V. alginolyticus isolates from diseased cultured gilt- head sea bream in Turkey.