IJA Volume 63, 2011
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ItemComparison of Growth in Pike-Perch (Sander lucioperca) and Hybrids of Pike-Perch (S. lucioperca) × Volga Pike-Perch (S. volgensis)(Israeli Journal of Aquaculture - BAMIGDEH, 2011)Growth of intensively cultured pike-perch Sander lucioperca (L.) and hybrids of pike-perch females × Volga pike-perch (S. volgensis Gmelin, 1789) males (1.75 g) were compared in a 35-day experiment. Fish were sorted into three groups (50 fish/aquarium): S. lucioperca grown separately (Group P), hybrids grown separately (Group H), and a mixed group of 25 S. lucioperca (Group Mp) grown together with 25 hybrids (Group Mh). The stocking density was 0.44 g/l. Final body weights were 6.83 g, 6.54 g, 5.17 g, and 4.84 g, and specific growth rates were 3.9%/day, 3.75%/day, 3.1%/day, and 2.89%/day, for groups Mp, P, Mh, and H, respectively. The weight, length, and specific growth rates of the S. lucioperca were significantly higher (p<0.05) than those of the hybrids, whether grown separately or together. The feed conversion rate of the hybrids grown separately was significantly higher (1.28 g/g) than all other groups. Further investigation is needed to study the growth performance of larger hybrids, to compare the hybrid with S. volgensis, and to investigate the possibility of cross hybridization.
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ItemReplacement of Fishmeal Using Poultry Offal Meal in Practical Feeds for Fry of the African Catfish (Clarias gariepinus)(Israeli Journal of Aquaculture - BAMIGDEH, 2011)A 70-day feeding trial was conducted to test the effect of partial replacement of fishmeal by poultry offal in the diet for fry of the African catfish, Clarias gariepinus. Four isonitrogenous rations containing replacement of 0 (control), 30%, 60%, or 90% fishmeal by poultry offal were fed to three replicate groups of C. gariepinus fingerlings (0.74 g). Growth performance and nutrient utilization of the fish were evaluated based on weight gain, protein intake, protein efficiency ratio, specific growth ratio, gross efficiency of food conversion, and carcass analysis. The average weight gains of fingerlings fed the control (2.43 g) and 30% replacement diet (2.31 g) were higher than in fish fed the 60% (2.09 g) and 90% (2.0 g) replacement diets. The feed conversion ratio (1.48-1.62) was lowest in fish fed the control diet and highest in fish fed the 90% replacement diet. The specific growth rate, protein efficiency ratio, and apparent net protein utilization significantly decreased (p<0.05) as the level of dietary poultry offal increased. It was concluded that replacement of up to 30% fishmeal by chicken offal meal enhances growth performance of C. gariepinus fry.
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ItemEffect of Three Diets on Growth and Survival Rates of African Catfish Heterobranchus bidorsalis Larvae(Israeli Journal of Aquaculture - BAMIGDEH, 2011)Investigations are underway in the Centre de Recherches Océanologiques d’Abidjan (Côte d’Ivoire) to find whether the catfish (Heterobranchus bidorsalis) could be an interesting aquaculture species. Within this framework a 28-day aquarium culture feeding trial was conducted to investigate the effects of three diets (Artemia salina nauplii, beef brain enriched with vitamins, and a compound food) on the growth and survival rates in 2-day post hatch H. bidorsalis. The feeding experiments started after the yolk sac of the larvae was absorbed (initial mean weight = 2.03±0.38 mg). Larvae fed Artemia nauplii had a higher growth rate (final mean weight = 708.60±411.61 mg] than those fed beef brain (381.81±118.88 mg) or compound food (102.72±48.09 mg). Conversely, the beef brain diet yielded a better survival rate (70.47±9.48%) than the Artemia nauplii (38.72±7.74%) or the compound diet (5.37±2.24%). Thus, beef brain can be used as a starter food for larval rearing of H. bidorsalis.
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ItemEffects of Dietary Pelargonium sidoides Extract on Growth Performance in Common Carp, Cyprinus carpio(Israeli Journal of Aquaculture - BAMIGDEH, 2011)The effects of graded dietary supplementation of Pelargonium sidoides extract on growth performance, feed utilization, and body composition in common carp, Cyprinus carpio, were preliminarily evaluated. Fish (0.67±0.05 g) were fed experimental diets containing 0, 1, 3, or 5 ml/100 g P. sidoides extract for 90 days. Growth rate significantly (p<0.05) increased in carp fed supplemented diets. The specific growth rate ranged from 2.87±0.09 in the control to 3.41±0.11 in fish fed the diet supplemented with 5 ml P. sidoides. The feed conversion ratio, protein efficiency ratio, and apparent net protein utilization were significantly better in groups fed diets with 3 or 5 ml P. sidoides extract than in the control or 1 ml group. The highest protein content (19.65%) was obtained with 3 ml supplementation. The present study shows that P. sidoides extract has a positive effect on carp growth and feed utilization with no apparent effects on health status.
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ItemPopulation Growth of Bosmina longirostris Fed Chlorella vulgaris and Scenedesmus subspicatus in Different Densities(Israeli Journal of Aquaculture - BAMIGDEH, 2011)In this study, the effects of the different densities of Chlorella vulgaris (0.05 x 106, 0.1 x 106, 0.2 x 106, 0.4 x 106, or 0.8 x 106 cells/ml) and Scenedesmus subspicatus (0.05 x 106, 0.1 x 106, 0.2 x 106, or 0.4 x 106 cells/ml) on culture of the water flea, Bosmina longirostris, were investigated. The experiment was carried out in a photoperiod of 16 h light:8 h dark at 25±1°C. At the beginning of the experiment, one B. longirostris individual (<24 h old) was put into each vessel, and the number of individuals and rate of population increase were determined for 30 days. Increasing the food density increased the number of individuals and the rate of population. The maximum number of B. longirostris individuals (7.1±2.08 ind/ml) and maximum rate of population increase (0.2±0.004/day) was in the group fed 0.2 x 106 cells/ml S. subspicatus. The effect on the number of the individuals was statistically significant (p<0.05).
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ItemEffect of Dietary Canola Oil Level on Fatty Acid Composition of Rainbow Trout (Oncorhynchus mykiss L.)(Israeli Journal of Aquaculture - BAMIGDEH, 2011)The effects of different levels of dietary canola oil on fatty acid composition of rainbow trout (Oncorhynchus mykiss) were investigated. Five experimental diets with equal protein (47%) and lipid (17%) contents were formulated for rainbow trout with a mean weight of 119±0.17 g. Canola oil was used to replace 0, 25%, 50%, 75%, or 100% of the fish oil in the control diet. Fish were fed twice daily to satiation for 70 days. At the end of the study, fatty acid compositions in the trout body mirrored the fatty acid compositions of the experimental diets. The highest fatty acids were palmitic acid (C16:0), oleic acid (C18:1n-9), linoleic acid (C18:2n-6), and docosahexaenoic acids (C22:6n-3). The study showed that, under our test conditions, canola oil can replace 100% of fish oil with no negative effect on the chemical or fatty acid composition of rainbow trout.
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ItemImproving Salinity Tolerance in Tilapias: Past Experience and Future Prospects(Israeli Journal of Aquaculture - BAMIGDEH, 2011)With increasing scarcity of fresh water available for aquaculture, especially in arid regions, development of tilapias that tolerate high salinity would increase fish (and hence, animal protein) production. We review culture practices, nutrition, physiology, and genetics, and propose approaches to improving salinity tolerance in tilapias. Physiological studies of biochemical pathways underlying phenotypic differences in salt tolerance can lead to genetic studies of intra and interspecific variation. Molecular technology can lead to studies on osmoregulation-related biochemical pathways, for which the euryhaline tilapia is an attractive model. Functional genomics and proteomics are powerful tools for studying the molecular bases of environmental adaptation and metabolic connections to osmoregulatory physiology. Both provide avenues for discovering novel pathways related to osmoregulation with relevance to aquaculture. Dietary supplementation with NaCl and optimized acclimation protocols are immediate and practical ways to improve salt tolerance. Inter-specific variation in salinity tolerance may be used to select salt-tolerant species and develop salt-tolerant hybrids. In the long term, quantitative trait loci associated with, or genes involved in, saltwater tolerance may facilitate marker-assisted or gene-assisted selection for this trait in tilapia.
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ItemThe Effects of Light Intensity and Color on Aggressive Interactions in the Dusky Kob, Argyrosomus japonicus(Israeli Journal of Aquaculture - BAMIGDEH, 2011)The dusky kob, Argyrosomus japonicus, is highly susceptible to stress under culture conditions. Such stress frequently involves a high degree of aggression, leading to cannibalism. Here, the effects of light intensity and color on the frequency of aggressive interactions and the time that passes between presentation of food and food first being eaten (feeding latency) in this species were examined. Aggression was lowest when fish were maintained in partial shade and highest in red light. Feeding latency was not affected by light treatment. The results can aid the aquaculture industry in determining the optimal light intensity for minimizing aggressive behavior in A. japonicus.
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ItemEfficacy of an Inactivated Vaccine and Nutritional Additives Against White Spot Syndrome Virus (WSSV) in Shrimp (Penaeus monodon)(Israeli Journal of Aquaculture - BAMIGDEH, 2011)Although the immune system of shrimps is not comparable to that of vertebrates, shrimps can acquire protection against pathogenic challenge by building up immunity. In this study, formalin-inactivated virus (FIV) was administered by injection, bath-immersion, or orally to determine levels of vaccination-mediated protection against the pathogenic white spot syndrome virus (WSSV). Diets supplemented with alfalfa, methyl sulfonyl methane (MSM), or wheat grass were provided with or without FIV. Shrimp injected with FIV and challenged 3, 15, or 30 days after vaccination had cumulative and relative survivals of 83%, 67%, and 33%, respectively. Survival of shrimp challenged by bath-immersion 3-45 days after vaccination by immersion was significantly higher than in the unvaccinated control. Orally vaccinated shrimp challenged by bath-immersion were partially protected up to 45 days after vaccination (cumulative survival 63.7%, relative 61.7%) but not til 60 days after vaccination (cumulative 8%, relative 3.2%). Survival of unvaccinated shrimp challenged by bath-immersion improved when shrimp were fed a diet supplemented with wheat grass or MSM, but not alfalfa. Survival was further enhanced when FIV was provided together with diets supplemented with wheat grass (cumulative 72.7%, relative 94.8%) or MSM (cumulative 73.3%, relative 96.3%).
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ItemThe Effects of Different Carotenoid Sources on Skin Pigmentation of Goldfish (Carassius auratus)(Israeli Journal of Aquaculture - BAMIGDEH, 2011)The aim of this study was to investigate the effect of different carotenoid sources on goldfish (Carassius auratus) skin pigmentation. The value of goldfish depends on the intensity of the skin color. In the red variety of goldfish, an orange-red hue is desirable. Juvenile goldfish were fed one of five diets for five months to determine the effects of carotenoids on skin pigmentation, growth, feed efficiency, and survival: (1) astaxanthin (carophyll pink at 75 mg/kg), (2) canthaxanthin (carophyll red at 75 mg/kg), (3) Gammarus spp. (75 mg/kg), (4) Oleoresin paprika (180 mg/kg), and (5) an unsupplemented control. Growth and feed efficiency did not significantly differ among groups. Initial and final samples of head skin were measured by colorimetric analysis for lightness (L*), redness (a*), yellowness (b*), hue (Hºab), and chroma (Cab*). The best red color (a* and Hºab) was obtained with the astaxanthin, canthaxanthin, and paprika diets.