IJA Volume 53, Issue 3-4, 2001
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ItemLength To Weight Relationship Of Sea Bass Lates Calcarifer (Bloch) Reared In A Closed Recirculating System(Israeli Journal of Aquaculture - BAMIGDEH, 2001)The length to weight relationship of sea bass, Lates calcarifer, reared for two years in our lab- oratory in an indoor recirculating system, was determined as follows: W (g) = 0.0107 TL (cm)3.0347, R2 = 0.9974. The values found in this study correspond to length/weight relation- ships found for a natural population by other researchers, indicating that sea bass cultivated in captivity under intensive conditions and at high stocking densities do not seem to differ in body appearance from those in nature.
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ItemEffects Of Light Intensity On Early Life Development Of Gilthead Sea Bream Larvae (Sparus Aurata)(Israeli Journal of Aquaculture - BAMIGDEH, 2001)The effects of different levels of illumination on sea bream (Sparus aurata, L. 1758) larvae were examined. The best total length development and highest survival rate were achieved in a dark environment. Illumination affected the relationships between total length and digestive tube length, total length and oil globule volume, and total length and yolk sac volume. The relationships between total length and digestive tube length, and total length and oil globule volume were not significant ly different (p>0.05) among groups whereas the relationship between total length and yolk sac volume was significantly different (p<0.05) between the group under 450 lux illumination and the group under 30 lux. All the relationships were significantly different (p<0.05) between groups kept in complete darkness and those which were illuminated.
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ItemUse of Juvenile Instar Diaphanosoma Celebensis (Stingelin) In Hatchery Rearing Of Asian Sea Bass Lates Calcarifer (Bloch)(Israeli Journal of Aquaculture - BAMIGDEH, 2001)The effects of size, dry mass intake and nutritional value of the brackishwater cladoceran, Diaphanosoma celebensis, on the growth and survival of 15-30 day sea bass (Lates calcarifer) lar- vae reared in a static green water system were determined. The highest specific growth rate (29.4%/day) was attained in larvae fed a 1:1 combination of Artemia nauplii and adult Diaphanosoma but it was not significantly different (p>0.05) from fish fed only adult Diaphanosoma (28.8%/day) or only juvenile instar Diaphanosoma (28.6%/day). Survival rates of larvae (92.4- 99.0%) fed the different live diets did not significantly differ (p>0.05). Larvae markedly prefered juve- nile instar Diaphanosoma over Artemia nauplii and adult Diaphanosoma. The crude protein con- tents of juvenile Diaphanosoma (58.7%), adult Diaphanosoma (58.3%) and Artemia (56.7%) were substantially high and satisfied the dietary protein requirements of larvae. The fatty acid profile of the sea bass fry reflected the lipid composition of the live diet. Improved growth, survival and dry mass intake in larvae indicate the potential of juvenile Diaphanosoma in the hatchery rearing of sea bass larvae.
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ItemGrowth Performance Of Hybrid Bass And Hybrid Tilapia In Conventional And Active Suspension Intensive Ponds(Israeli Journal of Aquaculture - BAMIGDEH, 2001)Recently developed, active suspension intensive ponds are based on the idea that fish ponds (aer- ated and mixed as required for the well-being of the fish) can also serve as water purification units. The present paper compares water quality and fish growth in conventional intensive ponds (daily water exchange 500%), with active suspension intensive ponds (daily exchange 8%). The fish test- ed were hybrid tilapia (Oreochromis niloticus x O. aureus), already known to perform well in active suspension units, and hybrid bass (Morone saxatilis x M. chrysops), which is commercially cultured in conventional intensive ponds. Water quality in the two types of intensive ponds differed as a result of the “internal water purifi- cation” vs “external water purification” approach. Bacterial development was greater in the active suspension ponds. Several parameters were affected by the different rate of water exchange, including temperature and removal of ammonium. The latter was lower in active suspension ponds due to reduced washout of particles and their associated nitrifying bacteria. Nitrification was greater in tilapia active suspension ponds because of grazing by this fish. Active suspension units operated with less than 2% of the water used in the conventional intensive ponds. Hybrid bass and hybrid tilapia performed similarly well in both types of pond, indicating the economic advantage of culturing them in the water-saving active suspension system. Tilapia graze on suspended parti- cles, leading to additional savings in feed costs. The good performance of hybrid bass in active suspension ponds is herein reported for the first time. * Corresponding author. Email: anamilst@netvision.net.il 2 Email: agyoram@techunix.technion.ac.il
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ItemEffects of Thermostable Bacterial α-AMYLASE On Growth Feed Utilization In Rohu, Labeo Rohita (Hamilton), Fingerlings(Israeli Journal of Aquaculture - BAMIGDEH, 2001)The effects of dietary supplementation of thermostable bacterial α-amylase (produced by Bacillus stearothermophilus, a thermophilic soil bacterium) on the growth, feed conversion, body composi- tion and digestive enzyme profile of rohu, Labeo rohita, fingerlings were evaluated. Rohu finger- lings (avg wt 0.99±0.01 g) were fed purified isonitrogenous diets (35% crude protein) with crude bacterial α-amylase at 350, 525, 700 and 850 U per 100 g feed for 60 days at 3% of their body weight. Fingerlings fed the enzyme-supplemented diets performed better than the control group which received no enzyme supplementation. The best performance in terms of percent weight gain, SGR, FCR and PER was achieved in fish fed the diet supplemented with 700 U of α-amylase. The bacterial α-amylase led to higher protein accretion and lipid depletion in the carcass up to the 700 U incorporation level. Intestinal protease and α-amylase activity increased in all groups com- pared to the initial level.
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ItemInfluence of Trout Cage Culture On Water Quality, Plankton And Benthos Anatolian Dam Lake(Israeli Journal of Aquaculture - BAMIGDEH, 2001)The effects of rainbow trout cage culture on water quality, phytoplankton, zooplankton and ben- thos were investigated in a cage farm of 30 ton capacity in Kesikköprü dam lake. Water tempera- ture did not differ among stations while dissolved oxygen and pH values were slightly lower in the station with cages. Significant and insignificant increases were detected in concentrations of ammonia, nitrate, orthophosphate and chlorophyll a in the cage station. Also, the abundance of phytoplankton, zooplankton and benthos was highest in the cage station. The composition of phy- toplankton was not fundamentally different among stations except for a higher abundance of Chlorophyceae and Cyanophyceae species in the cage station in November. The composition of zooplankton and benthos did not differ among stations; rotifers and gastropods were dominant, respectively.
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ItemProduction Of Heterozygous And Homozygous Clones Of Common Carp (Cyprinus Carpio L.): Evidence From DNA Fingerprinting And Mixed Leukocyte Reaction(Israeli Journal of Aquaculture - BAMIGDEH, 2001)The production of two heterozygous and one homozygous clones of the Israeli Dor-70 line of com- mon carp (Cyprinus carpio L.) was tested using DNA fingerprinting (DFP) and mixed leukocyte reaction (MLR) analysis. The clones were obtained in large-scale production from mitotic gyno- genetic females and males (sex-inversed). MLR analysis was used to examine major histocom- patibility complex (MHC) antigens in individuals. DFP provided evidence concerning identity in the whole genome. Both methods showed that individuals within a progeny were identical, confirming genetic uniformity within each clone and showing that no paternal DNA was transmitted during mitotic and meiotic gynogenesis. The results indicated that uniformity of DFP in progeny of the homozygous clone is obtained only when the mother is fully homozygous, and in the heterozygous clone only if both parents are fully homozygous. The results of both methods provide evidence, though indirect, that the mitotic gynogenetic parents of these fish (mother of the homozygous clone, mother and father of the heterozygous clones) were fully homozygous.
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ItemImmunogenicity Of Aeromonas Salmonicida A-Protein In Goldfish (Carassius Auratus L.)(Israeli Journal of Aquaculture - BAMIGDEH, 2001)Antigenicity of the surface A-layer protein of an atypical Aeromonas salmonicida strain was tested in goldfish following immunization with various A-protein (AP) antigenic preparations (soluble form, alum-precipitated, conjugated with polyacrolein nanoparticles, or bacterin). ELISA revealed innate specific anti-AP antibody activity in all fish on day 0, while no significant antibody enhancement was seen on days 21 or 42 following the primary immunization. A second stimulation with soluble AP resulted in a clear response in groups primed with bacterin and alum-precipitated AP but no response in those primed with soluble AP or AP-nanoparticles conjugate. The implication of these results for vaccine design is discussed.
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ItemRapid Wound Healing In African Catfish, Clarias Gariepinus, Fed Diets Supplemented With Ascorbic Acid(Israeli Journal of Aquaculture - BAMIGDEH, 2001)Wound healing in African catfish, Clarias gariepinus, fed diets supplemented with ascorbic acid was studied under laboratory conditions. Fish weighing approximately 80-110 g were stocked in 500 l aquaria in a static water system and fed one of five test diets containing different levels of microencapsulated ascorbic acid (0, 0.06, 0.10, 0.30 and 0.70 g AsA/100 g feed). After two weeks, all experimental fish were wounded by making a 1 x 1 cm dorso-lateral incision above the lateral line of the fish. Wounded tissues were sampled for histopathological analysis 4, 8, 24, 48 and 96 hours, 6, 8, 10, 12 and 14 days after making the incision. There were significant differences in weight gain, specific growth rate (SGR) and feed conversion ratio among the dietary treatments. Weight gain and SGR of fish fed the ascorbic acid free diet were lower than those of fish fed diets supplemented with ascorbic acid. The wound healing response showed a direct correlation to ascorbate level in the diet. Fibroblasts were present at 96 h irrespective of the ascorbic acid level. As 14 days, fish fed no ascorbic acid had some regeneration of muscle tissues, whereas fish fed diets containing supplemental ascorbic acid had a normal epidermis, dermis and muscle structure. There was no mortality during the experimental period, and fish fed ascorbic acid free diets did not exhibit any deficiency signs. Results of this study indicate that about 0.10-0.70 g AsA/100 g feed is needed for wound repair in African catfish.