IJA Volume 59, Issue 2, 2007
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ItemEffects of Early Weaning on Growth and Digestive Enzyme Activity in Larvae of Sea Bass (Dicentrarchus labrax L.)(Israeli Journal of Aquaculture - BAMIGDEH, 2007)The influence of early weaning on digestive enzymes, growth, and survival in sea bass larvae were investigated. Larvae were reared in a closed sea water system and first fed Artemia nau- plii eight days after hatching. Three weaning periods were compared by introducing a micropar- ticulate diet on day 15, 20, or 25. The control continued to be fed only Artemia. The lowest growth and survival rates were obtained in the 15-day group while the highest were in the 25- day group. After weaning, protease activities (trypsin, chymotrypsin, elastase, pepsin) dropped in all groups, indicating malnutrition. Amylase activity slightly increased in all experimental groups due to the higher starch content in the microparticulate diet than in Artemia and the absolute and relative lipid contents were lower in groups fed the microparticulate diet. Lipase activity suddenly dropped after weaning but slightly rose from day 35 until the end of the exper- iment (day 40). Due to decreased larvae development, survival, and digestive enzyme activity, weaning at 20 days after hatching, synchronous to formation of the stomach and enzymatic activity, is strongly recommended.
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ItemHeterosis in the Growth Rate of Hungarian-Israeli Common Carp Crossbreeds and Evaluation of their Sensitivity to Koi Herpes Virus (KHV) Disease(Israeli Journal of Aquaculture - BAMIGDEH, 2007)Koi herpes virus (KHV) disease first occurred in Israel in spring 1998. In search of genetic solu- tions to the disease, two strains of domesticated common carp (Szarvas-22 and Dinnyes) were imported from Hungary in 2002 to test their genetic contribution to KHV resistance and hetero- sis in growth parameters when crossed with a local strain (Dor-70). During 2004, six genetically different groups were reared, including the three above-mentioned strains and three crossbreeds (Szarvas-22 x Dor-70, Dinnyes x Dor-70, and Nasic x Dor-70). Fish were vaccinated by injection of an inoculum containing attenuated virus, individually marked, stocked in communal earthen ponds, and cultured to market size. Data on resistance to the disease and growth rates were col- lected. The two Hungarian strains and their crossbreeds had no advantage in specific resistance to KHV but contributed to heterosis when crossed with Dor-70. This was expressed by an increase of more than 10% and 20% in growth rate, compared to the commercial Israeli cross- breed (Nasic x Dor-70).
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ItemAmino Acid Composition of Heterobranchus longifilis Fry, Fingerlings, and Broodstock(Israeli Journal of Aquaculture - BAMIGDEH, 2007)The whole-body amino acid composition of fry, fingerlings, and brood fish of Heterobranchus longifilis was determined using a Technicon Sequential Multisample Auto-Analyser, equipped with a pen recorder for drawing chromatograms. The fish samples consisted of nine essential amino acids (arginine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threo- nine, valine) and eight nonessential amino acids (alanine, aspartic acid, cystine, glutamic acid, glycine, proline, serine, tyrosine). There were no significant differences among the three stages and all are closely related to those of other fish species.
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ItemRematuration of Spent Macrobrachium rosenbergii Female Broodstock through Dietary Manipulation and Eyestalk Ablation(Israeli Journal of Aquaculture - BAMIGDEH, 2007)The single or combined effects of artificial feed and eyestalk ablation on gonadal maturation of spent Macrobrachium rosenbergii female brooders was studied in 48 females. Significant differ- ences in percent weight gain, food conversion ratio, specific growth rate, gonado-somatic index, number of molts, molting interval, and ovarian development stages were observed. The highest numbers of molts and shortest molting intervals were found in eyestalk-ablated groups while higher percent weight gains were obtained in non-ablated groups. Groups fed formulated feed registered lower percent weight gains and higher FCRs than groups fed natural feed (clam and squid meat). Females in immature stages were found only in non-ablated groups while the only ovigerous females were found in the ablated group fed formulated feed. In short, unilateral eye- stalk ablation together with properly formulated feed (46.1% crude protein) could induce gonad maturation of spent female Macrobrachium rosenbergii brooders during the non-monsoon sea- son.
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ItemAntigenic Characterization of Outer Membrane Protein of Aeromonas sobria Isolated from Goldfish (Carassius auratus L.)(Israeli Journal of Aquaculture - BAMIGDEH, 2007)Aeromonas sobria, along with A. hydrophila, has frequently been reported as a causative agent of motile aeromonas septicemia (MAS) in fish and other aquatic organisms. Currently, there are no precise tools to diagnose or vaccinate against this disease. The aim of the present study was to fractionate and characterize the outer membrane protein (OMP) antigen of A. sobria by sero- logical and cellular techniques so as to identify immunoreactive molecules that might be useful in preparing immunodiagnostic and/or immunoprophylactic tools against A. sobria infection in goldfish. Eight fractions were isolated from the crude OMP antigen using sephacryl S-200 and DEAE-cellulose chromatography. The highest seroreactivity was observed in the gel-permeated protein G1 which had an optical density (OD) of 0.72 nm, higher even than that of the crude OMP antigen, 0.63 nm. The serodiagnostic potential of G1 was assessed by using dip-stick ELISA. The in vitro goldfish lympho-proliferation ability of the fractionated antigen, G1A3, was higher than of all the other fractionated antigens and the crude OMP. Therefore, fractionated antigen G1 (molecular wt 42-67 kDa) and G1A3 (molecular wt 45-47 kDa) should be further studied in immunodiagnostic and/or immunoprophylactic preparations for A. sobria infection.
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ItemEvaluation of Anchovy Meal and Soybean Meal as Dietary Protein Sources for the Black Sea Turbot, Psetta maxima(Israeli Journal of Aquaculture - BAMIGDEH, 2007)Soybean meal and locally-produced anchovy (Engraulis encrasicolus) fishmeal were evaluated as protein sources in the intensive culture of Black Sea turbot, Psetta maxima, by comparing them with imported Alaskan fishmeal. Three diets were prepared. One contained imported fish- meal and the second anchovy fishmeal. In the third diet, part of the anchovy fishmeal was replaced by soybean meal. The dietary protein levels were adjusted to approximately 50%. Juveniles (avg wt 8.2 g) were reared for 61 days in triplicate tanks. Growth and feed efficiency in fish fed the anchovy fishmeal diet were inferior to those of fish fed the imported fishmeal diet, indicating the need to improve the quality of the anchovy fishmeal. Partial replacement of the anchovy fishmeal by soybean meal resulted in worse growth performance. The low growth rates obtained with the anchovy fishmeal diet and the anchovy plus soybean diet were accompanied by low lipid and glycogen accumulation. Fatty acid compositions of the muscle and liver were not influenced by the dietary protein source. The inferior results with the soybean meal diet might have been due to effects of anti-nutrients on the digestive system.
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ItemThe Effect of Stocking Density on Yield, Growth, and Feed Efficiency of Himri Barbel (Barbus luteus) Nursed in Cages(Israeli Journal of Aquaculture - BAMIGDEH, 2007)Himri barbel (Barbus luteus Heckel, 1843) fingerlings (mean wt 15.73 g) were stocked at 40, 60, 80, or 100 fish per cage in 1-m3 cages suspended in a reservoir lake to determine total yield, growth rate, and feed efficiency after seven months. Total yields increased as the stocking den- sity increased and were 3.59, 4.80, 6.32, and 7.91 kg per cage, respectively. The highest mean fish weight was obtained in the lowest stocking density. Neither the food conversion ratio nor the mortality rate was affected by stocking density.
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ItemFishes of the Eastern Mediterranean(Israeli Journal of Aquaculture - BAMIGDEH, 2007)Few seas have evidenced an environmental impact throughout human history to the degree that the eastern Mediterranean has. In the last century alone, the Levant Basin has seen the opening of the Suez Canal, leading to a massive Red Sea biological invasion, and construction of the Aswan Dam on the Nile River, leading to an abrupt cessation of its annual floodwaters. These man-made activi- ties have had a serious impact on the eastern Mediterranean causing the collapse of some fisheries, the creation of others, and large- scale alterations in the ecosystem. This book deals with fish species living in the Levant Basin and includes all currently-known indige- nous and immigrant species.
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ItemImmunogenic and Antigenic Profiles of Nine Lactococcus garvieae Strains from Different Rainbow Trout Farms(Israeli Journal of Aquaculture - BAMIGDEH, 2007)The aims of this study were to determine differences with respect to immunogenic potency in the antigenic profiles of nine Lactococcus garvieae strains from Turkey, Spain, and England, to develop a bacterin, and to examine the immunological response of rainbow trout to the bacterin. The strains had identical Western blot patterns with 30, 37, 40, 46, 52, and 66 kDA mw protein bands. After culturing the bacteria, proteins were separated by SDS-PAGE and transferred to Immobilon membranes. The membranes were incubated with hyperimmune rabbit sera obtained by immunizing a rabbit against L. garvieae. One group of 50 fish was immunized with formalin- killed bacterin prepared from the most immunogenic strain of L. garvieae. A second group of 50 fish served as an unimmunized control. Four weeks after vaccination, both groups were chal- lenged intraperitoneally with a homologous strain. The protection rate of the bacterin was judged by the relative percent survival (RPS) of the groups. A significantly high level of protection was achieved in the vaccinated group (88.8% RPS).