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| Larviculture newsletter < Year 2005 < Issue 234 |
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| Larviculture newsletter < Year 2005 < Issue 234 |
IN VIVO TITRATION OF WHITE SPOT SYNDROME VIRUS (WSSV) IN SPECIFIC
PATHOGEN-FREE LITOPENAEUS VANNAMEI BY INTRAMUSCULAR AND ORAL ROUTES
C. M. Escobedo-Bonilla, M. Wille, V. Alday Sanz, P. Sorgeloos, M. B. Pensaert,
H. J. Nauwynck-2005
Dis. Aquat. Org. 66, 163-170
Abstract:
White spot syndrome virus (WSSV) is a devastating pathogen in shrimp aquaculture. Standardized challenge procedures using a known amount of infectious virus would assist in evalu¬ating strategies to reduce its impact. In this study, the shrimp infectious dose 50% endpoint (SID50 ml-1) of a Thai isolate of WSSV was determined by intramuscular inoculation (i.m.) in 60 and 135 d old specific pathogen-free (SPF) Litopenaeus vannamei using indirect immunofluorescence (IIF) and 1-step polymerase chain reaction (PCR). Also, the lethal dose 50% endpoint (LD50 ml-1) was deter¬mined from the proportion of dead shrimp. The median virus infection titers in 60 and 135 d old juve¬niles were 1068 and 106.5 SID50 ml-1, respectively. These titers were not significantly different (p z 0.05). The titration of the WSSV stock by oral intubation in 80 d old juveniles resulted in approxi¬mately 10-fold reduction in virus titer compared to i.m. inoculation. This lower titer is probably the result of physical and chemical barriers in the digestive tract of shrimp that hinder WSSV infectivity. The titers determined by infection were identical to the titers determined by mortality in all experi¬ments using both i.m. and oral routes at 120 h post inoculation (hpi), indicating that every infected shrimp died. The determination of WSSV titers for dilutions administered by i.m. and oral routes con¬stitutes the first step towards the standardization of challenge procedures to evaluate strategies to reduce WSSV infection.
(Laboratory of Aquaculture & Artemia Reference Center, Faculty of Bioscience Engineering, Ghent University, Rozier 44, 9000 Ghent, Belgium; email of C. M. Escobedo-Bonilla: cesar.escobedo@UGent.be; email of H. Nauwynck: hans.nauwynck@UGent.be)
PARTICLE SIZE DISTRIBUTION IN TWO LIPID EMULSIONS USED FOR
THE ENRICHMENT OF ARTEMIA NAUPLII AS A FUNCTION OF THEIR PREPARATION METHOD
AND STORAGE TIME
Kyungmin Han, Inge Geurden, Paul Van der Meeren, Sungchul C. Bai, Patrick Sorgeloos-2005
Journal of the World Aquaculture Society 36(2)
Abstract:
The present study examined the distribution of particle sizes
in two experimental standardized lipid emulsions (distributed by ICES, International
Council for the Exploration of the Sea) as a function of the preparation method
(hand shaking or ultrasonic blending) and as a function of storage time. A 24-h
enrichment trial compared the incorporated HUFA levels in the nauplii of Artemia
franciscana.
The emulsion droplets in the 50% HUFA emulsion (ICES 50, ethyl ester based)
were much smaller than in the 30% HUFA emulsion (ICES 30, triacylglycerol-based)
in which 90% of the droplets had a diameter below 12.3 pm as compared to 1.3
µm in ICES 50. The blending method highly affected particle sizes. High-shear
blending instead of the classical hand shaking of the emulsion of both ICES
30 and 50 reduced the mean particle size from 5.06 to 1.07 pm and from 0.38
to 0.11 pm, respectively. The particle size distributions remained stable during
the 1-wk storage, suggesting the absence of agglomeration or bacterial development.
The fatty acid composition of 24b enriched Artemia reflected differences in
the HUFA profile of the emulsions, but was independent of observed differences
in the size of the particles.
(Laboratory of Aquaculture & Artemia Reference Center, Ghent University, Rozier 44, 9000 Gent, Belgium; Kyungmin Han’s present address: Department of Aquaculture Feeds and Foods Nutrition Research Center, Pukyong National University, Busan 608-737 Korea)
A HISTOLOGICAL STUDY ON THE DEVELOPMENT OF THE DIGESTIVE SYSTEM
OF PSEUDOSCIAENA CROCEA LARVAE AND JUVENILES
K. Mai, H. Yu, H. Ma, Q. Duan, E. Gisberti, J. L. Zambonino Infante, C. L. Cahu-2005
Journal of Fish Biology 67, 1094-1106
Abstract:
The ontogenetic development of the gut and accessory organs in large yellow croaker Pseudosciaena crocea was investigated using light microscopy from hatching up to the juvenile stage (40 days post hatch, dph). At 3 dph (mean ± S.D., 4.1 ± 0.1 mm total length, LT), coincid¬ing with the buccopharynx opening, larvae started to feed exogenously, and the gut consisted of a well-developed buccopharynx, a partially-differentiated oesophagus and an intestine divided in three regions (anterior intestine, intermediate intestine and rectum). Yolk reserves were not completely depleted at the onset of exogenous feeding, and a period of mixed nutrition was observed up to 6 dph (4.3 ± 0.1 mm LT), when yolk was definitively exhausted. Important morphological changes occurred at the end of the larval period, coinciding with metamorphosis. At 17 dph (6.8 ± 0.6 mm LT), pyloric caeca differentiated at the junction of the pyloric stomach and the anterior intestine. Gastric glands were first observed at 21 dph (9.2 ± 1.2 mm LT), coinciding with the morphological development of the stomach in three different regions (cardiac, fundic and pyloric) according to the histological characteristics of their mucosa. At this age, large longitudinal folds appeared in the median and posterior oesophageal mucosa. These morphologi¬cal and histological features suggested the achievement of a digestive system characteristic of large yellow croaker juveniles and adults.
(Key Laboratory of Mariculture, Education Ministry of China, Ocean University of China, Qingdao 266003, China; email of K. Mai: kmai@ouc.edu.cn)
Press Release 23`d November, 2005
INTERNATIONAL GROUP MEETS TO PLAN FOR SUSTAINABLE FISH FARMING
A group of over a hundred stakeholders from 16 countries met this week in Oostende,
Belgium to draw up a series of measurable guidelines for the sustainable development
of aquaculture in Europe. With the increasing demand for seafood in Europe and
the declining return from wild fisheries, aquaculture is seen as the industry
that will meet this gap in the future. CONSENSUS - a multrstakeholder platform
for sustainable aquaculture in Europe - is an EU Sixth Framework initiative
funded under the Key Action of Food Quality and Safety. It is driven by major
European stakeholders representing consumer interests, aquaculture producers,
aquatic feed suppliers, environmental, animal heath and welfare groups as well
as from various levels of legislative bodies in both the EU and Member States.
"European aquaculture production of fish and molluscs rose from almost
690,000 tonnes in 1981 to over 1.293 million tonnes in 2001 and is expected
to outstrip wild fisheries production within twenty years," said Alistair
Lane, Executive Director of the European Aquaculture Society (EAS) who are co-ordinating
the project. "By 2001, aquaculture was contributing over 17% of the volume
and 27% of the value of fishery production in the European Union. In addition,
the Newly Associated States (NAS) bring an additional contribution of close
to 100.000 tonnes to freshwater aquaculture production (with carp species and
trout). This provides both opportunities and challenges. The main aim of CONSENSUS
is to ensure that sustainability becomes normal practice in this industry in
terms of the environment, social contribution and economic success into the
future."
Another major role of CONSENSUS is to demonstrate to consumers the health benefits
of eating fish and shellfish grown in sustainable conditions. Early results
from the meeting have already highlighted the beneficial effects of PUFA (polyunsaturated
fatty acids), trace elements and vitamins contained in seafood against heart
disease and other cardio-vascular complaints, as well as a wide range of other
medical conditions. Furthermore, new information from European surveys shows
that consumer perception of the safety and quality of farmed fish is now equal
to that of fish caught in the wild.
For further information please contact:
Mr. Alistair Lane,
Executive Director - European Aquaculture Society
Phone: + 32 59 323859; email: a.lane@aquaculture.cc
DOSE-DEPENDENT DECOMPOSITION RATE CONSTANTS OF HYDROGEN PEROXIDE
IN SMALL-SCALE BIO FILTERS
Lars-Flemming Pedersen, Per Bovbjerg Pedersen, Ole Sortkjær-2005
Aquacultural Engineering 34 (1): 8-15
Abstract:
This study investigated rates of hydrogen peroxide (H2O2) degradation
in biofilters, to provide information for more accurate treatment regimes in
recirculation systems and more accurate prediction of effluent H2O2 concentrations.
Sodium percarbonate (2Na2CO3•3H2O2) was applied to small-scale recirculation
systems with active bio filters. Three different treatment dosages corresponding
to an initial hydrogen peroxide (H2O2) concentration (C0) of 13.0, 26.0 or 39.0
ppm were used (N = 18). Decomposition rate constants (ke) of H2O2 were identified
by exponential regression analysis of recurrent water samples from treatment
start to complete decomposition. The chemical fate of H2O2 obeyed first order
kinetics with half-lives inversely correlated with C0. Decomposition rate constants
were significantly related to the amount of organic matter (BOD5) and initial
dosage of H2O2, and ranged from ke = 0.451 (C0 = 26 ppm; BOD5 = 2.0 mg O2/l)
to ke = 3.686 h-1(C0 = 13 ppm; BOD5 = 16.1 mg O2/l).
Surface specific reduction (SSR) of H2O2 in biofilters was positively related
to dosage concentration for both levels of BOD5, where SSR from 55 to 220 mg
H2O2 m-2 t-1 were found.
Oxygen liberation was positive correlated to C0 and BOD5, indicating that hyperoxic
conditions can arise if large amounts of sodium percarbonate are added to water
with high organic matter content.
This study assesses the environmental fate of H2O2 in a closed recirculation
system with biofilters, simulating recirculation aquaculture systems. The information
can be applied to hydraulic model to predict actual treatment concentrations
in aquaculture facilities and to assess effluent pulse from simulated treatment
regimes.
(Danish Institute for Fisheries Research, Department of Marine Ecology and Aquaculture, North Sea Centre, P.O. Box 101, DK-9850 Hirtshals, Denmark; email of Lars-Flemming Pedersen: lfp@dfu.min.dk)
REMOVAL OF NITRATE IN AQUARIA BY MEANS OF ELECTROCHEMICALLY
GENERATED HYDROGEN GAS AS ELECTRON DONOR FOR BIOLOGICAL DENITRIFICATION
R. Grommen, M. Verhaege, W. Verstraete-2005
Aquacultural Engineering 34(1): 33-39
Abstract:
A hydrogenotrophic denitrification reactor was designed for the removal of nitrate from aquaria. An average hydrogen gas transfer up to 130 mg per day from the gas to the water phase was accomplished by recirculating the water from the denitrification reactor over a separate trickling filter column with a volume of 1.3 l. During batch experiments removal rates up to 36 mg N/l reactor per day were recorded at a hydraulic residence time of 12 h. To avoid the need for storage of large volumes of hydrogen gas in aquarium or aquaculture applications, an electrochemical cell was used to generate hydrogen gas. During a 7 day aquarium test, a nitrate removal rate up to 18.5 mg N/l reactor per day was recorded at an influent NO3-–N concentration of 20 mg/l.
(Laboratory of Microbial Ecology and Technology (LabMET), Ghent University, Coupure Links 653, B-9000 Gent, Belgium; email of W. Verstraete: Willy.Verstraete@UGent.be)
PERFORMANCE EVALUATION OF RADIAL/VERTICAL FLOW CLARIFICATION
APPLIED TO RECIRCULATING AQUACULTURE SYSTEMS
William Johnson, Shulin Chen-2005
Aquacultural Engineering 34(1): 47-55
Abstract:
A prototype radial/vertical clarifier with 60° cone bottom was built and evaluated for application in recirculating aquaculture. Samples were analyzed for particle size distribution using a laser diffraction particle analyzer (Mastersizer S, Malvern Instruments Ltd., Worcestershire, UK) and total suspended solids (TSS) to determine the effectiveness of the clarifier. Surface area calculated mean influent and effluent particle diameters were 81.12 ± 1.57 µm and 54.48 ± 0.79 µm, respectively—a 33% reduction in mean particle size. Mean particle size within the system was 73.19 ± 1.37 µm. Mean influent and effluent particle diameters, based upon volume, were 340.62 ± 3.59 µm and 176.07 ± 2.37 µm, respectively, with a resulting overall particle size reduction of 48%. Average TSS was relatively low at all sampling points, 11.4 mg/L, 2.1 mg/L and 2.6 mg/L for influent, effluent and system sampling points, respectively, with a resulting average removal rate of 82%. The authors believe the suitability of radial/vertical flow clarifiers as a water efficient, low cost alternative solids collection device for recirculating aquaculture was demonstrated.
(Department of Biological Systems Engineering, Washington State University, P.O. Box 646120, Pullman, WA 99164, USA; email of W. Johnson: wjohnson3@wsu.edu)
REVIEW:
INTRODUCTION OF GENETIC ENGINEERING IN AQUACULTURE: ECOLOGICAL AND ETHICAL IMPLICATIONS
FOR SCIENCE AND GOVERNANCE
Anne Ingeborg Myhr, Roy Ambli Dalmo-2005
Aquaculture 250(3-4): 542-554
Abstract:
Within aquaculture, genetic engineering (GE) is emerging as a powerful method for breeding of fish and shellfish, and for developing alternative sources of feed and vaccines to combat diseases. On the other hand, the use of GE in aquaculture raises ecological, ethical and economic concerns. For instance, genetically modified (GM) feed could be spread to the aquatic environment and consumed by other marine organisms, and horizontal gene transfer may conceivably occur from DNA in feed or vaccines to a recipient genome or by faeces to the environment. Numerous reports have described beneficial effects such as viral disease resistance following DNA vaccination. However, side effects, such as activation of other genes than those which are central in immune defence mechanisms, may occur and warrant further investigations. In order to achieve sustainable introduction of GE, it is crucial that appropriate scientific investigations and ethical considerations are done prior to large-scale introduction of GE products such as DNA/GE vaccines and GM feed in commercial fish farming. This may result in a solid basis for the avoidance of potentially undesirable health and environmental effects. If GE can help make aquaculture a sustainable industry, this opens the possibility of positive market and consumer responses. This can best be achieved by involving the stakeholders from the conceptual stage to the commercial stage by facilitating a transparent process whose purpose is to inform research, to identify decision stakes, and to influence design, adoption and implementation of pro-active policy.
(Norwegian Institute of Gene Ecology, The Science Park, P.O. Box 6418, N-9294 Tromsø, Norway; email of Anne Myhr: annem@fagmed.uit.no)
REVIEW:
THE IMPACT OF NUTRITION ON METAMORPHOSIS IN ATLANTIC HALIBUT (HIPPOGLOSSUS HIPPOGLOSSUS
L.)
Kristin Hamre,, Mari Moren, Jostein Solbakken, Ingegjerd Opstad, Karin Pittman-2005
Aquaculture 250 (3-4): 555-565
Abstract:
Fatty acids, vitamin A and thyroid hormone have all been shown to affect development of flatfish larvae and they are ligands to nuclear receptors that participate in the control of development. Our hypothesis was that one of these factors or an interaction between them may be the cause of abnormal development of flatfish larvae. Atlantic halibut larvae were fed either DHA-selco-enriched Artemia or copepods from first feeding. In fish that had been fed Artemia, only 7% had normal pigmentation and 10% normal eye migration. The numbers for fish fed copepods were 68% and 88%, respectively. Malpigmented fish fed Artemia were depigmented, while those fed copepods had ambicoloration. The differences in development were probably nutrient dependent, since all other conditions were similar for the two groups. Larvae fed copepods had markedly higher body levels of docosahexanoic acid (DHA, 22:6n-3) and eicosapentaenoic acid (EPA, 20:5n-3) and lower levels of arachidonic acid (ARA, 20:4 n-6) than larvae fed Artemia. The DHA/EPA ratio was similar in the two groups, but the EPA/ARA ratio was more than four times higher in larvae fed copepods than in larvae fed Artemia. Larvae fed copepods had higher body levels of total retinol than larvae fed Artemia, but the difference was due to higher levels of the storage forms, retinyl esters, whereas the levels of free retinol and retinal were similar in the two groups. The level of iodine was 700 times higher in copepods than in Artemia and 3–4 times higher in larvae fed copepods than in larvae fed Artemia. There was a significantly higher level of T4 in larvae fed copepods during the “window of opportunity”, 15–30 days after first feeding. In an experiment where Atlantic halibut larvae were fed Artemia enriched in iodine up to the levels found in copepods, there was a significant effect on the body level of iodine and a non-significant tendency of higher levels of thyroid hormone, but no effect on pigmentation or eye migration. It is concluded that Artemia probably offers a sufficient access to vitamin A precursors to meet the larval requirement. More research should be done to elucidate possible effects of iodine on development of Atlantic halibut larvae. Fatty acid composition is still the most likely candidate for causing abnormal development in Atlantic halibut larvae.
(National Institute of Nutrition and Seafood Research (NIFES), P.O. Box 2029, Nordnes, N-5817 Bergen, Norway; email of Kristin Hamre: kristin.hamre@nifes.no)
PATHOGENICITY OF WHITE SPOT SYNDROME VIRUS ON POSTLARVAE AND
JUVENILES OF PENAEUS (LITOPENAEUS) VANNAMEI
Franklin Pérez, Filip A.M. Volckaert, Jorge Calderón-2005
Aquaculture 250 (3-4): 586-591
Abstract:
White Spot Syndrome Virus (WSSV) has decimated the shrimp aquaculture around the world. Breeding efforts to generate resistant stocks are necessary but there is a lack of basic information on challenge test strategies focused on genetic selection. Infection routes and developmental stages were evaluated on Penaeus vannamei as a first step in a strategy to select white spot virus (WSSV)-resistant stocks. Mortalities could not be induced before the PL30 stage. The impact of infection by immersion and blended tissue was intermediate on mortalities when compared to the minced tissue treatment on PL30. Blended and minced tissue treatments produced the highest mortalities on PL40 while immersion was intermediate. A general tendency towards higher susceptibility associated with older stages was detected. Additionally, juveniles of 1 g average weight from three local breeding programs were challenged. There were no differences in survival between the programs, although two of them derived their progenies from survivors of strong WSSV events. The implications of these results to the WSSV epidemiological characteristics and breeding programs are discussed.
(Fundación CENAIM-ESPOL, Campus “Gustavo Galindo Velasco,” P.O. Box 09-01-4519, Km. 30.5 Vía Perimetral, Edificio #34, Guayaquil, Ecuador; email of F. Pérez: franklinperez@hotmail.com)
EFFECTS OF SEED SIZE AND DENSITY ON GROWTH, TISSUE-TO-SHELL
RATIO AND SURVIVAL OF CULTIVATED MUSSELS (MYTILUS EDULIS) IN PRINCE EDWARD ISLAND,
CANADA
Jean-Sébastien Lauzon-Guay, Mark Dionne, Myriam A. Barbeau, Diana J.
Hamilton-2005
Aquaculture 250 (3-4): 652-665
Abstract:
In suspended aquaculture, the size of mussel seed and the density at which these mussels are placed in socks are two important factors affecting mussel production. However, the effect of these two factors has yet to be examined simultaneously. We conducted two large-scale field experiments to assess the effect of seed size and initial density on growth, tissue-to-shell ratio and survival of blue mussels (Mytilus edulis) grown on longlines. Experimental mussel sites were set up during the autumn of two consecutive years in two bays on the north shore of Prince Edward Island, Canada. At each site, socks containing combinations of three seed sizes (small, medium and large) at two initial densities (low and high) were deployed and monitored over time. Small seed grew faster than large seed and often reached commercial size in the same time period. Furthermore, initial density generally did not affect shell growth. During the pre-spawning period following the autumn deployment, seed at low initial density had a higher tissue-to-shell ratio than seed at high initial density, especially for large seed. This effect of initial density disappeared in early summer. Early in the experiments (< about 10 months), mussel survival on socks was affected by seed size only: small seed generally had lower survival rates than larger seed. Late in the experiments (> 10 months), there appeared to be an interaction between seed size and initial density on mussel survival: survival of small seed generally decreased with increasing initial density, while survival of large seed was not affected by initial density. Since large seed tended to be packed at lower initial density than small seed, lack of crowding was likely responsible for the absence of density-dependent loss. Our study thus assessed different seeding strategies, and results were generally consistent across years and sites.
(Department of Biology, University of New Brunswick, Bag Service 45111, Fredericton, New Brunswick, Canada E3B 6E1; email of J.S. Lauzon: js.lauzon@unb.ca)
TWO MONOCLONAL ANTIBODIES FOR THE RECOGNITION OF MYTILUS SPP.
LARVAE: STUDIES ON CULTURED LARVAE AND TESTS ON PLANKTON SAMPLES
Silvia Lorenzo-Abaldea, África González-Fernández, Encarnación
de Miguel Villegas, José Fuentes-2005
Aquaculture 250 (3-4): 736-747
Abstract:
Monoclonal antibodies (mAbs) were generated against 2-day-old mussel larvae in an attempt to develop a rapid and rigorous method for the identification of mussel larvae in field plankton samples. Previously, we have shown that two of these mAbs recognised Galician Mytilus galloprovincialis obtained from monospecific cultures, but did not recognise the larvae of other bivalve species present in that area. To assess the possibility of using these mAbs in routine assays for measuring the abundance of mussel larvae in plankton, studies on cultured mussel larvae, at different stages of development, and tests on bivalve larvae from plankton samples were carried out. Initially, to see whether the two mAbs also recognise other mussel larval stages, they were tested against mussel larvae of different ages obtained from monospecific cultures. The results indicate that both antibodies stain all the stages tested, even 1-month-old postlarvae. In addition, we also demonstrate that these mAbs also recognise other forms of Mytilus. Both antibodies bind to M. galloprovincialis larvae from the Mediterranean Sea and M. edulis larvae. Finally, and more significantly, studies on field plankton samples were performed to confirm if both mAbs are really mussel-specific, and do not cross-react with larvae of any other bivalve species existing in the plankton. The results presented here clearly indicate that our two monoclonal antibodies specifically recognise the mussel larvae in field plankton samples from different geographical regions, but not the larvae of any other bivalve species. Thus, these monoclonal antibodies could be used for routine monitoring of mussel larvae in plankton samples from different sources.
(Centro de Investigacións Mariñas (CIMA), Consellería de Pesca e Asuntos Marítimos, Xunta de Galicia, P.O. Box 13, E-36620 Vilanova de Arousa, Pontevedra, Spain; email of S. Lorenzo-Abaldea: silvi@uvigo.es)
IN VIVO DRY MATTER AND PROTEIN DIGESTIBILITY OF THREE PLANT-DERIVED
AND FOUR ANIMAL-DERIVED FEEDSTUFFS AND DIETS FOR JUVENILE AUSTRALIAN REDCLAW,
CHERAX QUADRICARINATUS
Alfredo Campaña-Torres, Luis R. Martinez-Cordova, Humberto Villarreal-Colmenares,
Roberto Civera-Cerecedo-2005
Aquaculture 250 (3-4): 748-754
Abstract:
Dry matter and protein digestibility of three plant-derived and four animal-derived feedstuffs and diets in which they were included were evaluated for juvenile Australian redclaw. The ingredients evaluated were: soy paste, textured wheat, sorghum meal, two sardine meals (67% and 58% crude protein), squid meal, and red crab meal. A reference diet was formulated and produced in the CIBNOR nutrition laboratory. Seven experimental diets were then made including 15% of each ingredient in the reference diet. The experiment consists of a single-factor, completely randomized design with five replicates per treatment. Digestibility was measured indirectly, using chromic oxide as a marker. Plant-derived ingredients and the corresponding diets had, in general, a higher digestibility than animal ingredients. Soy paste and sorghum meals, and the diets in which they were included, showed an excellent dry matter (over 87%) and protein (approximately 90%) digestibility. Some of the animal ingredients such as sardine meal 67% CP and squid meal had a good dry matter digestibility (over 80%), but were significantly lower than plant-derived ingredients. The lowest dry matter and protein digestibility was recorded for sardine meal 58% CP and red crab meal. It is concluded that juvenile redclaw are omnivorous and able to efficiently consume diets containing plant- and animal-derived ingredients, but they can digest plant-derived ingredients more efficiently.
(Dictus, Universidad de Sonora, Apdo Postal 1819, Hermosillo, Sonora 83000, Mexico; email of Luis R. Martinez-Cordova: lmtz@guaymas.uson.mx)
THE EFFECT OF DIETARY PROTEIN REPLACEMENT BY CRYSTALLINE AMINO
ACID ON GROWTH AND NITROGEN UTILIZATION OF TURBOT SCOPHTHALMUS MAXIMUS JUVENILES
Helena Peres, Aires Oliva-Teles-2005
Aquaculture 250 (3-4): 755-764
Abstract:
A study was conducted to evaluate the effect of partial replacement
of dietary fish meal by crystalline amino acids on growth performance, feed
utilization, body composition and nitrogen utilization of turbot juveniles.
Four diets were formulated to be isolipidic (12% DM) and isonitrogenous (8%
DM). A fish meal based diet was used as control. In the experimental diets,
a crystalline amino acid (AA) mixture was used to partially replace fish meal,
corresponding to a non-protein nitrogen content of 19, 37 and 56%, respectively
(diets 19AA, 37AA and 56AA, respectively). The overall amino acid profile of
the experimental diets resembled that of the whole-body protein of turbot. Each
experimental diet was fed to triplicate groups of 20 fish (initial body weight
of 31.8 g) twice daily to apparent satiation for 42 days. During the trial water
temperature averaged 18 °C.
Final body weight, weight gain (g kg ABW- 1 day- 1) and specific growth rate
were not different between the control and 19AA diet but significantly decreased
with the increase of crystalline-AA inclusion from 19 to 56%. Feed intake and
feed efficiency of fish fed the control and diet 19AA were similar and significantly
higher than those of fish fed the 56AA diet. At the end of the growth trial,
there were no significant differences in whole-body composition among groups.
Hepatosomatic index was also unaffected by dietary treatments.
Nitrogen retention (g kg ABW- 1 day- 1) of fish fed the control
and the 19AA diets were similar and significantly higher than that of fish fed
the other diets. Expressed as a percentage of the nitrogen intake, N retention
was significantly higher with the control than with the 37AA and 56AA diets.
Daily ammonia excretion (mg kg ABW- 1 day- 1) of fish fed the control diet was
significantly higher than that of fish fed the 37AA and 56AA diets, while daily
urea excretion (mg kg ABW- 1 day- 1) did not significantly differ among treatments.
Non-fecal nitrogen (ammonia + urea) excretion (mg kg ABW- 1 day- 1) was significantly
higher for fish fed the control diet than in those fed the 37AA and 56AA diets.
However, as percent of N intake, ammonia excretion and non-fecal N excretion
were significantly higher in fish fed the 56AA diet than in those fed the control
and 19AA diets.
Specific activity of glutamate dehydrogenase, alanine and aspartate aminotransferases
did not significantly differ among experimental groups.
In conclusion, in diets with an overall amino acid profile resembling that of
the whole-body protein of turbot, crystalline-AA may replace 19% of dietary
protein without negatively affecting growth performances or feed utilization
efficiency. However, higher protein replacement levels of protein-bound-AA by
crystalline-AA severely depressed growth performance.
(CIIMAR-Centro Interdisciplinar de Investigação Marinha e Ambiental, Rua dos Bragas 289, 4050-123 Porto, Portugal; email of Aires Oliva-Teles; aoteles@fc.up.pt)
EFFECT OF DIETARY TAURINE LEVELS ON GROWTH AND FEEDING BEHAVIOR
OF JUVENILE JAPANESE FLOUNDER PARALICHTHYS OLIVACEUS
Shin-Kwon Kim, Toshio Takeuchi, Masahito Yokoyama, Yuko Murata, Masaki Kaneniwa,
Yoshitaka Sakakura-2005
Aquaculture 250 (3-4): 765-774
Abstract:
This study was conducted to investigate the effect of dietary
taurine levels on growth and feeding behavior of juvenile Japanese flounder.
Three different taurine level diets were prepared by supplementation of taurine
(T-0%, 0.5% and 1.5%) to the basal diet. Fish meal washed with 70% ethanol to
remove taurine was used as the sole protein source. Feeding experiments were
carried out twice at 20 °C by using different size of fish (average body
weight: 0.3 g in Experiment I and 3.7 g in Experiment II). The feeding behavior
of fish was observed throughout the experimental period. At the end of experiments,
fish were killed for amino acids analysis.
The final average body weight and feed efficiency of juvenile Japanese flounder
fed the T-1.5% diet was significantly higher than those of fish fed the T-0%
diet in Experiments I and II. Abnormal feeding behavior such as multiple feeding
while swimming in the water column was observed in the T-0% group in Experiment
I. These findings indicate that taurine is essential for normal growth and development
of normal feeding behavior of juvenile Japanese flounder.
(Graduate School of Marine Science and Technology, Tokyo University of Marine Science and Technology, Minato, Tokyo 108-8477, Japan; email of T.Takeuchi: take@s.kaiyodai.ac.jp)
GROWTH EFFICIENCY OF JUVENILE BARRAMUNDI, LATES CALCARIFER,
AT HIGH TEMPERATURES
Robin S. Katersky, Chris G. Carter-2005
Aquaculture 250 (3-4): 775-780
Abstract:
Temperature is recognized to be the most important environmental factor affecting growth in fish. Barramundi are cultured over a wide range of temperatures some of which approach the upper thermal tolerance for this species. A growth trial was conducted on juvenile barramundi to examine the effects of high temperatures ranging from the minimum optimal temperature (27 °C) for growth efficiency to the extreme upper thermal limits (39 °C) for feed intake, growth and growth efficiency. Juveniles (4.87 ± 0.32 g) were held at four different temperatures 27, 33, 36 and 39 °C and fed twice daily to satiation (503.5 g kg- 1 crude protein, 182.5 g kg- 1 lipid, 150.1 g kg- 1 ash, 20.52 GE MJ kg- 1). Feed intake (g•day- 1) and SGR (%•day- 1) increased with increasing temperature up to 36 °C. At 39 °C feed intake, growth, feed efficiency ratio, protein efficiency ratio and productive energy value were significantly lower than at the other temperatures. This demonstrates that growth was optimized at temperatures from 27 to 36 °C and that barramundi have a much wider range for maximum growth efficiency than previously thought.
(School of Aquaculture, Tasmanian Aquaculture and Fisheries Institute, University of Tasmania, Locked Bag 1370, Launceston, Tasmania 7250, Australia; email of R. Katersky: robink@utas.edu.au)
USE OF FORMULATED DIETS AS REPLACEMENTS FOR ARTEMIA IN THE
REARING OF JUVENILE AMERICAN LOBSTERS (HOMARUS AMERICANUS)
Michael F. Tlusty, Denise R. Fiore,Jason S. Goldstein-2005
Aquaculture 250 (3-4):781-795
Abstract:
American lobsters, Homarus americanus, have been successfully reared in hatchery operations for over a century, yet formulated diets have never been commercially produced. In recent years, commercial Artemia replacement (CAR) diets have been developed and marketed for use in aquaculture production of marine shrimp. Three separate experiments assessed the utility of rearing American lobsters on these shrimp CAR diets. First, survival and growth of stage IV American lobsters fed one of three CAR diets (Artemac 5, CAR1; Economac 4, CAR2; and Progression 3, CAR3) were compared to those of animals fed frozen adult n-3 fatty acid enriched Artemia. Survival to 3 months was highest for animals fed CAR3 (85%), while animals fed Artemia had the greatest weight gain (> 6 % day- 1). A cost / benefit ratio analysis showed that CAR2 was the most cost efficient for juvenile production because of its low overall purchase cost. Second, stage IV lobsters were fed either CAR2 or frozen adult n-3 fatty acid enriched Artemia exclusively, or in combination (2 : 5, and 5 : 2). Again, CAR2 was a cost effective feed to use, even as a partial replacement for Artemia. Survival was higher in diets that included CAR2, and feeding it two days per week compensated for low quality Artemia. Finally, 1.5 year old lobsters fed a gelatin-bound mix of 80% CAR2 and 20% frozen Artemia for five months survived and grew equally well compared to lobsters fed gelatin-bound frozen adult Artemia, and better than a custom formulated maintenance diet. The benefits of incorporating formulated feeds into American lobster rearing programs to increase the effectiveness of enhancement programs is discussed.
(New England Aquarium, Central Wharf, Boston, MA 02110 USA; email of M. Tlusty: mtlusty@neaq.org)
THE USE OF LUTEINIZING HORMONE RELEASING HORMONE ANALOGUE FOR
OVULATION INDUCTION IN BLACK SEA BASS (CENTROPRISTIS STRIATA)
David L. Berlinsky, William King V, Theodore I.J. Smith-2005
Aquaculture 250 (3-4): 813-822
Abstract:
Interest in commercial production of black sea bass has increased in recent years, but reliable spawning methods remain problematic. The objective of this study was to evaluate the effects of oocyte size and luteinizing hormone releasing hormone analogue (LHRHa) dosage and delivery systems on ovulatory success for in vitro fertilization. Vitellogenic females with maximum oocyte diameters of 400–625 µm were implanted with a 95% cholesterol–5% cellulose pellet containing 50 µg of LHRHa. Fish with maximum oocyte diameters < 450 µm failed to ovulate. In contrast, 90% of fish with 500 µm oocytes spawned within 36 h and 40% of this group ovulated a second time. All of the females containing oocytes > 550 µm ovulated. In a second experiment, females with uniformly vitellogenic oocytes (> 500 µm) and implanted with 50 µg LHRHa ovulated substantial numbers of eggs (45,000–192,000 eggs/kg body weight (BW), but fertility was consistently low (0–15%). In a third experiment, 19 of 39 females receiving implants containing 6.3–23.6 µg LHRHa/kg BW during the spawning season ovulated, but fecundity (17,000–339,000 eggs/kg) and fertilization (0–98%) were highly variable. When fish were grouped by developmental index, calculated as the number of oocytes with diameters > 400 µm/total number of oocytes measured, there were no statistical differences among groups with respect to the number of spawns, fecundity or fertilization success. In a fourth experiment, 11 of 13 females with a clutch of fully vitellogenic oocytes that were injected with 20 or 100 µg/kg BW LHRHa ovulated between 1 and 2 times on consecutive days. Five of seven given an implant containing 12.5 µg LHRHa ovulated one or more times. Fish implanted with shams or injected with vehicle alone did not ovulate in any of the experiments. No differences were found in the number of spawns, fecundity or fertilization success from fish receiving different doses of injected or implanted LHRHa. Incubation of pooled eggs produced 155,000 larvae (60% hatch) and 95,000 one-gram juveniles. These results demonstrate that injected or implanted LHRHa is effective for inducing ovulation in black sea bass with maximum oocyte diameters > 500 µm.
(Department of Zoology, University of New Hampshire, Durham, NH 03824, USA; email of D. Berlinsky: David.Berlinsky@unh.edu)
EFFECTS OF TEMPERATURE, SALINITY AND PH ON LARVAL GROWTH, SURVIVAL
AND DEVELOPMENT OF THE SEA CUCUMBER HOLOTHURIA SPINIFERA THEEL
P.S. Asha, and P. Muthiah-2005
Aquaculture 250 (3-4): 823-829
Abstract:
For large-scale seed production of sea cucumbers through a hatchery system, it is imperative to know the effects of environmental parameters on larval rearing. Auricularia larvae (48 h post-fertilization) were obtained from induced spawning of Holothuria spinifera and used in experiments to ascertain the effects of temperature, salinity and pH on the growth and survivorship of the larvae. The larvae were reared for 12 days at temperatures of 20, 25, 28 and 32 °C; salinities of 15, 20, 25, 30, 35 and 40 ppt; and pH of 6.5, 7.0, 7.5, 7.8, 8.0, 8.5 and 9.0. The highest survivorship and growth rate and fastest development of auricularia indicated that water temperature of 28–32 °C, salinity of 35 ppt and pH of 7.8 were the most suitable conditions for rearing larvae of H. spinifera.
(Tuticorin Research Centre of CMFRI, 115 N.K. Chetty Street, Tuticorin 628 001, India; email of P.S. Asha: ashasanil@yahoo.com)
THE EFFECTS OF TEMPERATURE AND FOOD RATION ON METABOLITE CONCENTRATIONS
IN NEWLY SETTLED KING SCALLOP (PECTEN MAXIMUS) SPAT
L.E. Hawkins, S. Hutchinson, I. Laing-2005
Aquaculture 250 (3-4): 841-848
Abstract:
Juvenile king scallop (Pecten maximus L.) between 0.2 and 1.5 g wet shell weight per individual, reared at 10, 14 and 17 °C, were fed either a full ration equivalent to 0.5 g (ash-free dry weight of algae) g- 1 (live weight of spat) week- 1 or a restricted algal ration of 0.07 g (ash-free dry weight of algae) g- 1 (live weight of spat) week- 1. The algal food was a mixture of two microalgal species: Chaetoceros ceratosporum (Droop) Green and Pavlova lutheri Ostenfeld. Measurements were made of tissue concentrations of adenylate tri-, di- and mono-phosphate, lactate, succinate, acetate, pyruvate and l-alanine. The metabolite measurements were used as indicators of viability in animals exposed to a matrix of temperature and food supply conditions. It was found that the variations in metabolic responses could be correlated with those observed in a previous study that measured body condition in relation to the same set of variables. It was also found that the data from the present study were most strongly influenced by temperature-related effects and that there was an optimal temperature range between 10 and 14 °C. The metabolic responses, measured in terms of metabolite concentrations, would seem to confirm the existence of a bi-stable physiology in P. maximus in which there is a switch in state between 10 and 14 °C.
(School of Ocean and Earth Science, University of Southampton, Southampton Oceanography Centre, European Way, Southampton SO14 3ZH, UK; email of L. E. Hawkins: leh@soc.soton.ac.uk)
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