Volume 64, 2012

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    Genetic Diversity among Wild and Cultured Stocks of Sparus aurata on Turkish Mediterranean Coasts Revealed by Mitochondrial DNA Sequences
    ( 2012) Dognakaya, L. ; Bekcan, S.
    The sequences of three mitochondrial DNA genes - 12S rRNA, cytochrome b, cytochrome oxidase II - were used to deduce genetic diversity and relationships among wild and cultured populations of gilthead sea bream (Sparus aurata) on Turkish coasts and coastal waters. The 415 bp of 12S rRNA, 605 bp of cytochrome oxidase II, and 557 bp of cytochrome b genes were sequenced and the data set was analyzed with Neighbor Joining and Minimum Evolution. Bootstrap analyses (1000 replicates) were performed and the relationships between samples are given in phylogenetic trees. Genetic diversity was estimated using gene diversity, number of haplotypes, and nucleotide diversity. There were no significant differences in variation in any of the three gene sequences. The maximum genetic variation occurred in cytochrome b (0.0050). Similarly, results showed very little divergence between sampling sites. Findings indicate a single wild population in the eastern Mediterranean, supporting the current classification that lacks subdivisions. Further, no differentiation between wild and culture stocks was inferred.
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    Nibbling Frequency of Carps in Periphyton-Based Aquaculture Systems with and without Supplemental Feed
    ( 2012) Rai, Sunila ; Yi, Yang
    The nibbling frequency of five carp species (rohu Labeo rohita, mrigal Cirrhinus mrigala, catla Catla catla, common carp Cyprinus carpio, silver carp Hypophthalmichthys molitrix) on bamboo lateral sticks (kanchi) colonized by periphyton was examined in fed and unfed systems. There were three treatments: (a) no carp and no supplemental feed (control), (b) carp without supplemental feeding (unfed treatment), and (c) carp with supplemental feeding (fed treatment). For 12 h (07:30-19:30) during six days, nibbling behavior was observed in real time via a digital video camera and recorded on a camcorder for later viewing. Rohu, catla, and common carp nibbled on the kanchi, while mrigal and silver carp did not. In rohu and catla, the nibbling frequency was significantly higher in the unfed treatment than in the fed treatment (p<0.05); supplemental feeding reduced nibbling frequency by 81% and 91%, respectively. Hence, in periphyton-based aquaculture systems, there is no need for a high density of substrates in ponds that receive supplemental feed. Alternatively, the amount of supplied feed can be reduced to force these species to consume more periphyton.
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    Effects of Dietary Fish Oil Substitution with Palm Oil on Growth, Survival, and Muscle Proximate Composition of Cirrhinus mrigala (Hamilton, 1822)
    ( 2012) Singh, Soibam Khogen ; Rather, Mohd Ashraf ; Mandal, Sagar C. ; Das, Pronob ; Pawar, Nilesh ; Singh, Y. Jackie ; Dar, Shabir Ahmad
    A 60-day growth experiment was carried out to evaluate the effect of replacing dietary cod liver oil with palm oil on the growth, survival, and muscle proximate composition of the Indian major carp, Cirrhinus mrigala. Five diets were fed to triplicate groups of 20 advanced C. mrigala fry (2.16±0.01 g): 100% cod liver+0% palm (control), 25% palm+75% cod liver, 50% palm+50% cod liver, 75% palm+25% cod liver, and 100% palm+0% cod liver. At the end of the experiment, mean weight gain, average daily growth, specific growth rate, feed conversion efficiency, feed conversion ratio, and percentage survival were assessed. Growth performance and survival were not compromised when fish oil was substituted with palm oil up to 25%. However, beyond this level, growth was significantly retarded (p<0.01). There were no significant (p>0.01) differences in feed efficiency or muscle proximate composition. Results confirm the feasibility of substituting up to 25% dietary fish oil by palm oil in diets for C. mrigala advanced fry without negatively affecting growth or feed utilization efficiency.
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    Effect of Stocking Density on Growth and Survival of Sub-Adult Tench (Tinca tinca Linnaeus 1758)
    ( 2012) Pantazis, Panagiotis A.
    Three hundred and fifty-nine (359) sub-adult tench were allocated to twelve tanks to investigate the effect of stocking density on survival and growth. The experimental population consisted of two weight groups (small = 11.27-11.36 g and large = 15.38-15.44 g) and two initial stocking densities (1.4 kg/m3 and 2.5 kg/m3). The experiment lasted seven months (217 days). The total lack of deformities in the caudal peduncle in all groups and the low incidence of mortality indicate that sub-adult tench cultured in a water recirculation system perform well when stocked at a relatively high stocking density (2.5 kg/m3) and fed 1.0% of their body weight per day. By the end of the experiment, the weight of the best-performing groups increased 83-90% and confirmed the hypothesis that high densities favor the growth and survival of sub-adult tench reared in artificial tanks in a water recirculation system.
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    An Improved Method of DNA Extraction from the Shell of the Pacific Oyster, Crassostrea gigas
    ( 2012) Zhang, Guofan ; Wang, Xiaotong ; Song, Xiaorui ; Li, Li
    We earlier developed a method to extract DNA from in vivo-sampled mantle tissue of the bivalve Pacific oyster (Crassostrea gigas) for molecular marker-assisted selection (MAS) in breeding. However, mortality was too high when using this method. In the current study, a more efficient and safer method of extracting DNA from the oyster shell was developed, based on the improved phenol-chloroform DNA extraction method. Both nuclear DNA and mitochondrial DNA were successfully extracted from the oyster shell, and mortality was 0%. These results illustrate the safety of extracting DNA from the bivalve shell. In addition, because DNA is a cellular component, the results provide molecular evidence that cells are likely involved in shell formation.
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    Sperm Characteristics of Wild European Flounder (Platichthys flesus luscus)
    ( 2012) Sahin, Temel ; Günes, Erdinç ; Aydin, Ilhan ; Kurtoglu, Ilker Zeki
    The spermatologic characteristics of European flounder (Platichthys flesus luscus) were determined. Flounder were collected during the spawning season and sperm of eight males was extracted by abdominal massage. Body weight and total length of the flounder were measured, volume, motility, duration of motility, spermatocrit, density, and pH of the sperm were determined, and correlations between the spermatologic characteristics and weight and length were investigated. Mean values were 0.7±0.16 ml for sperm volume, 87.5±3.66% for motility, 22.0±1.49 min for duration of motility, 94.0±1.22% for spermatocrit, 2.7±0.16 × 109/ml for density, and 6.9±0.05 for pH. Body length and sperm volume had positive correlations with body weight (p<0.01), but the correlation between length and sperm volume was negative (p<0.01). Likewise, the correlations between spermatocrit and total length, sperm volume, and density were negative (p<0.05).
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    Pigmentary and Zootechnical Responses of Juvenile Litopenaeus vannamei (Boone, 1931) Maintained on Diets Supplemented with Xanthophylls of Marigold Tagetes erecta Flowers
    ( 2012) Piña-Valdéz, Pablo ; Aguirre-Hinojosa, Eduardo ; Garza-Aguirre, María del Carmen ; Montoya-Olvera, Ricardo ; Torres-Quiroga, José Odón ; Nieves-Soto, Mario
    Practical diets supplemented with 75 or 150 ppm xanthophylls (75% zeaxanthin, 15% lutein) industrially extracted from marigold (Tagetes erecta L.) flowers increased the astaxanthin and total carotenoid concentrations in juvenile Litopenaeus vannamei, compared to shrimp fed a practical control diet. Our results paralleled or exceeded those obtained with a diet containing 75 ppm supplementary synthetic astaxanthin. The post-feeding astaxanthin concentration accounted for more than 84% of the total carotenoid concentration in shrimp fed either diet, while beta-carotene, zeaxanthin, lutein, and other non-identifiable carotenoids comprised a minority of the total concentration. That this was seen in both the tail exoskeleton and abdominal muscle indicates that L. vannamei can metabolize precursor xanthophylls to produce astaxanthin. In most cases, more than 60% of the astaxanthin was esterified. In general, survival improved in shrimps fed the supplemented diets compared to those fed the control diet. There were no differences in growth.
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    Stress Survival in Larvae of Florida Pompano (Trachinotus carolinus) Fed Enriched Rotifers (Brachionus plicatilis) and Nauplii of the Calanoid Copepod (Pseudodiaptomus pelagicus)
    ( 2012) Cassiano, Eric J. ; Ohs, Cortney L. ; DiMaggio, Matthew A.
    The Florida pompano, Trachinotus carolinus, is a highly prized marine fish whose larviculture includes the feeding of live rotifers and brine shrimp nauplii. In a previous study, growth and survival of pompano larvae fed nauplii of the calanoid copepod, Pseudodiaptomus pelagicus, were compared to those of larvae fed enriched rotifers, Brachionus plicatilis. There were advantages to including the copepod in the larvae diet. The current study examines the stress tolerance of such larvae. Two trials were conducted: for seven (trial 1) and nine (trial 2) days post-hatch. Larvae were fed diets that included enriched rotifers and/or P. pelagicus nauplii and subjected to varying durations of air exposure (‘sieve stress’). Larvae fed copepods exhibited significantly greater stress tolerance than larvae fed only enriched rotifers. In trial 1, stress tolerance increased as the number of days on which copepods were fed increased. It is possible that stress tolerance improved because of a better nutritional profile of the copepod nauplii.
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    Effects of Total Replacement of Fishmeal with Spirulina Powder and Soybean Meal on Juvenile Rainbow Trout (Oncorhynchus mykiss Walbaum)
    ( 2012) Hernández, Luis Héctor Hernández ; Flores, Gerardo Hernández ; Araiza, Mario Alfredo Fernández ; López, Omar Angeles
    Juvenile rainbow trout (Oncorhynchus mykiss) were fed diets in which fishmeal was totally replaced by mixtures of Spirulina powder and soybean meal. Three experimental diets were formulated with 75% Spirulina and 25% soybean meal, 50% Spirulina and 50% soybean meal, and 25% Spirulina and 75% soybean meal. A commercial diet and a diet with 100% fishmeal served as controls. Diets were fed to triplicate groups of 10 juveniles with an initial weight of 6.8±0.4 g for 50 days. At the end of the experiment, growth performance, oxygen consumption, nitrogen and phosphorus excretion, protein digestibility, and serum protein content and lysozyme activity were evaluated. Data were analyzed by one-way ANOVA. Growth performance was not significantly affected by the experimental diets, but values tended to be lower as the level of dietary soybean meal increased. Among the experimental diets, the 75% Spirulina/25% soybean diet produced the best growth performance. Further, in fish fed this diet, the apparent coefficient of digestibility of protein was higher than 98% (as with all diets), oxygen consumption was lower and lysozyme activity was higher than in fish fed other replacement diets, and dissolved phosphorus and phosphorus in feces were similar or lower than in the controls. The present research shows the possibility of using mixtures of Spirulina powder and soybean meal as total substitutes of fishmeal in diets for juvenile rainbow trout.
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    Effect of Dietary Supplementation of Achyranthes aspera Seed on the Immune System of Labeo rohita Fry
    ( 2012) Chakrabarti, R. ; Srivastava, P. Kumar
    Labeo rohita (rohu) fry (0.547±0.01 g) were fed one of four diets containing 0 (control), 0.1, 0.5, or 1.0% Achyranthes aspera seed. After 30 days, the fry were immunized with chicken red blood cells (c-RBC). Blood samples were collected 7, 14, and 21 days after immunization. Significantly (p<0.05) higher average weight (2.565±0.02 g) and SGR were were obtained in fry fed the 1.0% diet compared to others. The increase in average weight was directly related to the increasing dose of seed. FCR was significantly (p<0.05) lower in fry fed the 1.0% diet while total serum protein, albumin, and globulin were higher in treated groups than in the unsupplemented control. The antigen-specific antibody titer level was significantly (p<0.05) lower in rohu fed the control diet than in rohu fed the supplemented diets. Titer levels were 32-128, 128-256, 256-1024, and 256-1024 in the 0, 0.1, 0.5, and 1.0% diets, respectively. Serum glutamic oxaloacetic transaminase (SGOT), serum glutamate pyruvate transaminase (SGPT), and alkaline phosphatase (ALP) were significantly (p<0.05) higher in rohu fed the control diet than in rohu fed the supplemented diets while myeloperoxidas was lower in the former. Among the treated groups, myeloperoxidase was significantly (p<0.05) higher in rohu fed the 1.0% diet (1.561-2.558, ? 450 nm) than in those fed other diets. The present study documents the immunostimulatory properties of A. aspera seed and finds that a dose of 1.0% might be suitable for rohu fry.