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| Larviculture newsletter < Year 2006 < Issue 237 |
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| Larviculture newsletter < Year 2006 < Issue 237 |
FOOD SELECTIVITY OF SEVEN-BAND GROUPER EPINEPHELUS SEPTEMFASCIATUS
LARVAE FED DIERENT SIZES OF ROTIFERS
Yukari Tanaka, Yoshitaka Sakakura, Hisashi Chuda, Atsushi Hagiwara, Susumu Yasumoto-2005
Nippon Suisan Gakkaishi 71 (6), 911-916
Abstract:
We investigated feeding selectivity on dierent sizes of rotifers (lorica length 90-241 µm) of seven-band grouper Epinephelus septemfasciatus larvae. Larvae ranging from 2.0 mm in standard length (SL, rst feeding) to 3.0 mm SL positively selected 101-160 µm rotifers, while larvae ranging from 3.0-4.0 mm SL selected 121-180 µm rotifers. Fish bigger than 4.0 mm SL showed a preference for over 160 µm rotifers. In seedling production of this species, small-sized rotifers (<160 µm) are necessary during the first feeding (<3.0 mm SL), and large-sized rotifers (=160 µm) are appropriate for larvae bigger than 3.0 mm SL.
(Graduate School of Science and Technology, Nagasaki University,
Nagasaki 852-8521, Japan)
EFFECTS OF OOCYTE DIAMETER ON OVULATION TIME, QUANTITY AND
QUALITY OF EGGS IN YELLOWTAIL SERIOLA QUINQUERADIATA IN INDUCING OVULATION WITH
HCG
Hisashi Chuda, Takahiro Nakao, Toshihisa Arakawa, Michiya Matsuyama-2005
Nippon Suisan Gakkaishi 71 (6), 942-946
Abstract:
Effects of initial oocyte diameter on ovulation time, quantity and quality of eggs in yellowtail, Seriola quinqueradiata, in inducing ovulation with HCG were examined. After measuring the oocyte diameter through ovarian biopsy, all sh (n=33) were divided into three groups according to their oocyte size: 650-700, 700-750, and 750-800 µm, and injected with HCG (500 IU/kg BW). Ovulation was induced in All the sh of the three groups, and the relationship between elapsed time until ovulation (T, hr) and oocyte diameter (D, µm) was represented as follows: T=-0.082D+105.99 (R2=0.51). 530 thousand eggs per sh could be obtained from sh with oocyte diameter over 700 µm, while only half the number of eggs could be collected from sh with oocyte diameter of 650-700 µm. High fertilization rates of over 90% could be obtained from all three groups regardless of the initial oocyte diameter when the articial insemination had been performed just after ovulation. However, the hatching rates rose with the increase of initial oocyte diameter. Thus, measuring the initial oocyte diameter before the HCG injection enables estimation of the ovulation time, number and quality of ovulated eggs in yellowtail.
(Nagasaki Prefectural Institute of Fisheries, Nagasaki 851-2213,
Japan)
EFFICACY OF FORMALIN AS AN EGG DISINFECTANT FOR IMPROVING HYBRID
CATFISH (CHANNEL CATFISH × BLUE CATFISH) HATCHING SUCCESS
Brian. C. Small, Nagaraj Chatakondi-2006
North American Journal of Aquaculture 68: 9–13
Abstract.:
Formalin is currently the only aquaculture drug approved by the U.S. Food and Drug Administration for the control of fungi on the eggs of all finfish. The efficacy of formalin for disinfecting hybrid catfish (channel catfish Ictalurus punctatus × blue catfish I. furcatus) eggs was examined and compared with that of three other potential chemotherapeutants. Two experiments were conducted to evaluate treatment dose and frequency on the hatching success of the hybrid catfish. In the first experiment, hybrid catfish egg masses were divided and assigned to 1 of 13 treatments administered as daily 15-min baths. The treatments were as follows: (1) control (no treatment), (2) 50 ppm (mg/L) formalin (F), (3) 100 ppm F, (4) 200 ppm F, (5) 125 ppm hydrogen peroxide (HP), (6) 250 ppm HP, (7) 500 ppm HP, (8) 50 ppm povidone iodine (PI), (9) 100 ppm PI, (10) 200 ppm PI, (11) 2.5 ppm copper sulfate (CS), (12) 5 ppm CS, and (13) 10 ppm CS. Hatching success tended to be highest among eggs treated with 100 ppm F (87.7%), 2.5 ppm CS (87.0%), or 100 ppm PI (85.2%), although these success rates were not significantly (P > 0.05) different from that in the control treatment (82.8%). Treatment with 500 ppm HP resulted in a significant (P < 0.05) decrease in hatching success (31.5%). In the second experiment, the optimal frequency of formalin treatments was assessed by treating hybrid catfish eggs zero, two, three, or four times daily. Eggs treated three times daily with 100 ppm F had the highest (P < 0.05) percentage of hatched eggs. To maximize hatching success, three daily treatments of hybrid catfish eggs with 100 ppm F as a 15-min bath is recommended.
(U.S. Department of Agriculture, Agricultural Research Service,
Thad Cochran National Warmwater Aquaculture Center, Catfish Genetics Research
Unit, Post Office Box 38, Stoneville, Mississippi 38776, USA)
SURVIVAL OF POSTLARVAL MACROBRACHIUM ROSENBERGII AT TWO TEMPERATURES
A. A. Ortega-Salas, F. C. Arana-Magallón-2006
North American Journal of Aquaculture 68: 34–35
Abstract.:
Postlarvae of the giant Malaysian prawn Macrobrachium rosenbergii were reared for a 120-d period under laboratory conditions at 20°C and 33°C to calculate survival. Ninety-six 50-d-old postlarvae were stocked in eight 70-L aquaria. A balanced commercial feed containing 40% protein was supplied daily at 20% to 9% of body weight during the first 2 months and at 5% to 3% of body weight during the final 2 months. Live brine shrimp Artemia franciscana were also provided as a supplemental food (10 organisms/L). Survival was 81% at 33°C and 67% at 20°C. The difference was statistically significant (P < 0.001) throughout the study period. Basic knowledge of rearing requirements under artificial conditions will be important for the production of juveniles as stock for large-scale prawn culture.
(Instituto de Ciencias del Mar y Limnologia, Universidad Nacional
Autónoma de México, Calzada Joel M. Camarena s/n, Mazatlán
82040, Sinaloa, Apartado Postal 811, México)
COMPARISON OF HATCHERY PERFORMANCE, AGONISTIC BEHAVIOR, AND
POSTSTOCKING SURVIVAL BETWEEN DIPLOID AND TRIPLOID RAINBOW TROUT OF THREE DIFFERENT
UTAH STRAINS
Eric J Wagner, Ronney E Arndt, M. Douglas Routledge, David Latremouille, Roger
F Mellenthin-2006
North American Journal of Aquaculture 68: 63–73
Abstract.:
The hatchery performance (growth, feed conversion, and survival) of rainbow trout Oncorhynchus mykiss was compared between diploid and triploid fish from three Utah strains: Fish Lake–DeSmet (FD), Sand Creek (SC), and Ten Sleep (TS). For FD, specific growth rates were slightly higher for triploids (2.79%/d) than for diploids (2.60%/d), but final mean weight at 108 d did not significantly differ. For SC and TS, there were no significant differences in final mean weight or specific growth rates after 138 or 122 d, respectively. Feed conversion ratios and fish mortality in the raceways did not differ significantly between diploids and triploids, except for SC for which mortality rates were slightly higher for triploids (4.0%) than diploids (2.1%). Possible differences in agonistic behavior between diploids and triploids were assessed by video observation of size-matched pairs (diploid-diploid, diploid-triploid, or triploid-triploid). There were no significant differences between diploid and triploid fish of any strain in the number of chases or counterattacks. To determine whether there were any differences in susceptibility to stocking and handling stressors, each strain was transported at high density for 4 h, then stocked into (1) tanks with ambient hatchery well water (control), (2) tanks with either high pH and high temperature (FD) or high temperature (TS and SC), or (3) the tail end of the raceway from which it came. There were no significant differences in mortality after 96 h between diploid and triploid fish for any of the three strains for any of the treatments. Poststocking survival of FD in a small, spring-fed lake was assessed by gill netting in the spring after fall stocking. No significant difference in overwinter survival was noted between diploid and triploid FD. Overall, the data indicate that triploid SC, FD, and TS rainbow trout perform equally well in the hatchery as diploid fish.
(Fisheries Experiment Station, Utah Division of Wildlife Resources,
1465 West 200 North, Logan, Utah 84321, USA)
CHARACTERIZATION OF AN EXPERIMENTAL INDOOR LARVAL PRODUCTION
SYSTEM FOR RED SNAPPER
John T Ogle, Jeffrey M Lotz-2006
North American Journal of Aquaculture 68: 86–91
Abstract.:
Over the past several years, we have developed an experimental-scale rearing system for larval red snapper Lutjanus campechanus that combines extensive outdoor production of live-feed zooplankton with intensive larval fish rearing. The salient features of the system are (1) use of size-graded copepods as live feed; (2) culture in clear water; (3) three-phase water management consisting of an initial static water phase followed by a volume-doubling phase in which water is gradually added and, finally, a recirculation–biofiltration phase; (4) a lowered salinity of 25 g/L water; and (5) an indoor location at constant temperature under artificial light. A total of 19,835 juvenile red snapper were produced from 12 larval rearing tanks in three separate batches with an overall survival of 16.5%. Survival varied from 1% to 31% in individual larval rearing tanks. Water quality variables (oxygen, temperature, salinity, total and un-ionized ammonia, nitrite, nitrate, pH, and alkalinity) were not significantly correlated with larval fish survival. A mean number of 5.36 copepods/mL was added daily to larval tanks during the culture period, with a range of 0.57–23.48 copepods/mL. There was no correlation between mean feed rates and survival in individual tanks. The mean residual copepods per milliliter averaged 2.24, with a range of from 0 to 15.86. There was a significant negative correlation between residual copepod density and survival.
(Gulf Coast Research Laboratory, University of Southern Mississippi,
Post Office Box 7000, Ocean Springs, Mississippi 39566, USA)
THE STABILITY OF ASCORBIC ACID IN ARTEMIA URMIANA FOLLOWING
ENRICHMENT AND SUBSEQUENT STARVATION
M. Noshirvani, A. Gh. Takami, A. Rassouli, S. Bokaee-2006
J. Appl. Ichthyol. 22 : 85-88
Abstract:
The effects of vitamin enrichment on ascorbic acid (AA) levels in Artemia urmiana were studied by applying an emulsion containing ascorbyl palmitate (AP) as a vitamin C source. Nauplii were kept at 28°C in incubators containing the enrichment medium (cod liver oil, AP, sodium polysorbate, a-tocopherol and tap water) for 0, 12, 18 and 24 h and then starved at 5°C for 0, 12, 18 and 24 h. AA was determined using a reversed phase high performance liquid chromatography coupled to an electrochemical detector. The results showed that nauplii of A. urmiana had high levels of ascorbic acid in their body tissues (1534 +/- 166 µg g-1 dry weight) and that the AA concentration increased following enrichment. The maximum enrichment level was reached by hour 18, declining in hour 24. There was a significant difference in AA levels between enriched and non-enriched Artemia (P < 0.05). Although AA contents were enhanced in all groups during starvation in cold conditions, the increases were not considerable. However, a clear correlation could be observed between duration of starving and rise in AA levels in non-enriched and 12 and 18 h enriched groups.
(Department of Aquatic Health and Diseases, Faculty of Veterinary
Medicine, Tehran University, Tehran, Iran)
THE ONTOGENY OF THE ALIMENTARY TRACT DURING LARVAL DEVELOPMENT
IN COMMON PANDORA PAGELLUS ERYTHRINUS L.
V. Micalea , M. Garaffo, L. Genovesea M.T. Spedicato, U. Muglia-2006
Aquaculture 251 (2-4): 354-365
Abstract:
The ontogenesis of the alimentary tract and its associated structures (liver, pancreas, gall bladder) was studied histologically in common pandora from hatching (0 DAH, days after hatching) until day 50 (50 DAH). Larvae were obtained by natural spawning from a broodstock adapted to captivity. They were stocked in 1500 l tanks supplied with Isochrysis galbana and Tetraselmis suecica from hatching until the Artemia feeding stage, at a temperature of 18.5–20 °C. Larvae were fed Selco-enriched Brachionus plicatilis from day 3, Artemia nauplii from day 28 and formulated feed from day 35. At hatching, the digestive tract was a histologically undifferentiated straight tube lying dorsally to the yolk sac. At first feeding (3–4 DAH) both the mouth and anus had opened and the digestive tract was differentiated into four portions: buccopharynx, oesophagus, incipient stomach and intestine. The pancreas, liver and gall bladder were also differentiated at this stage. Within 2 days after the commencement of exogenous feeding, the anterior intestinal epithelium showed large vacuoles indicating the capacity for absorption of lipids, whereas supranuclear ninhydrin-Schiff (NS) positive inclusions indicating protein absorption were observed in the posterior intestinal epithelium. Both the bile and main pancreatic ducts had opened in the anterior intestine, just after the pyloric sphincter, at this stage. Intestinal coiling was apparent since 4 DAH, while mucosal folding began at 10 DAH. Scattered PAS-positive mucous cells occurred in the oral cavity and the intestine, while they were largely diffused in the oesophagus. Gastric glands and pyloric caeca appeared at 28 DAH, indicating the transition from larval to juvenile stage and the acquisition of an adult mode of digestion.
(Consiglio Nazionale delle Ricerche-Istituto per l'Ambiente
Marino Costiero (CNR-IAMC), sez. di Messina-spianata S.Raineri 86, 98122 Messina,
Italy; email of V. Micalea: valeria.micale@iamc.cnr.it)
PRELIMINARY STUDIES ON THE CRYOPRESERVATION OF GILTHEAD SEABREAM
(SPARUS AURATA) EMBRYOS
E. Cabrita, V. Robles, J.C. Wallace, M.C. Sarasquete, M.P. Herráez-2006
Aquaculture 251 (2-4) : 245-255
Abstract:
Vitrification could provide a promising tool for the cryopreservation of fish embryos. In order to achieve successful cryopreservation, several parameters should be taken into account in the design of a vitrification protocol. In the present study some relevant factors were investigated (permeable and non-permeable cryoprotectant toxicity, toxicity of vitrificant solutions, adequate container for embryo loading and temperature of thawing) using two gilthead seabream embryonic development stages (tail bud and tail-bud-free). Permeabilized embryos were incubated in dimethyl sulfoxide (DMSO), methanol (MeOH), ethylene glycol (EG) and 1,2-propanediol (PROH) in concentrations ranging from 0.5 to 6 M for 10 and 30 min and in 5%, 10% and 15% polyvinyl pyrrolidone (PVP), 10%, 15% and 20% sucrose or 0.1%, 1% and 2% X1000® for 2 min. After treatment, embryos were washed and incubated in seawater until hatched. The toxicity of permeable cryoprotectants increased with concentration and exposure time. EG was best tolerated by the embryos. Exposure to non-permeable cryoprotectants did not affect the hatching rate except at F stage. Six vitrificant solutions (DMSO—V1, V2 and V3 and EG—V1, V2 and V3) were tested using a stepwise incorporation protocol. The DMSO-based solutions contained 5 M DMSO + 2 M MeOH + 1 M EG plus 5% PVP, 10% sucrose or 2% X1000® and the EG-based solutions contained 5 M EG + 2 M MeOH + 1 M DMSO plus 5% PVP or 10% sucrose. Before loading the embryos into 0.5 ml straws or 1 ml macrotubes, toxicity tests were effected with these solutions. Our results demonstrated that DMSO-based solutions were better tolerated by seabream embryos than EG-based solutions. After thawing (water bath, 0 or 25 °C), embryos were evaluated by stereoscopic microscopy and the percentage of embryos with intact morphology was registered. The highest percentage of embryos with intact morphology (28%) was observed in samples frozen in macrotubes and thawed at 25 °C. Several malformations associated with ice crystal formation inside the embryos were detected. None of these embryos achieved hatching. Our results suggest that the absence of a proper incorporation of cryoprotectants prior to vitrification is the main problem that must be overcome. This procedure should be optimized in order to avoid ice crystal formation inside embryo compartments.
(Center for Marine Sciences-CCMAR, University of Algarve, Campus
de Gambales, 8000 Faro, Portugal; email of E. Cabrita: ecabrita@ualg.pt)
A BIOLOGICALLY BASED DAMAGE ASSESSMENT MODEL TO ENHANCE AQUACULTURAL
WATER QUALITY MANAGEMENT
Jeng-Wei Tsai, Chung-Min Liao, Vivian Hsiu-Chuan Liao-2006
Aquaculture 251 (2-4): 280-294
Abstract:
The lethal concentration for 50% of aquacultural animals (LC50)-based tests determines the external effect concentration (EEC) following certain statistical models, revealing that no biologically based mechanistic information and only statistical interpretations of its model parameters could be made. The purpose of this paper is to determine the survival risk of waterborne metals toward farmed species with respect to lethality based on biologically based mechanistic models. Here we study a biologically based mechanistic damage assessment model (DAM) compared with a pharmacodynamic (PD)-based critical area under the curve (CAUC) model to demonstrate the ability of predicting the internal effect concentration (IEC) and survival rate of farmed species. We tested the proposed models using published acute toxicity and accumulation data for two farmed species, tilapia (Orechromis mossambicus) exposed to arsenic (As) and abalone (Haliotis diversicolor supertexta) exposed to zinc (Zn), to compare observed and predicted LC50 and IEC and, subsequently, to predict the survival rate. Our analyses demonstrate that the DAM- and PD-based survival models performed well and proved its usefulness as a tool in the quantification of risk assessment in aquacultural ecosystems. The study also supports the suggestion that replacing exposure-based EECs by IECs is a first step toward a measure for inherent toxicity and can be used to improve the construction of future environmental quality criteria programs aimed at protecting and restoring the rapidly degrading aquacultural ecosystems.
(Ecotoxicological Modeling Center, Department of Bioenvironmental
Systems Engineering, National Taiwan University, Taipei 10617, Taiwan, ROC;
email of C.-M. Liao: cmliao@ntu.edu.tw)
DEVELOPMENT OF THE DIGESTIVE CAPACITY IN LARVAE OF HADDOCK
(MELANOGRAMMUS AEGLEFINUS) AND ATLANTIC COD (GADUS MORHUA)
J.C. Perez-Casanova, H.M. Murray, J.W. Gallant, N.W. Ross, S.E. Douglas, S.C.
Johnson-2006
Aquaculture 251 (2-4): 377-401
Abstract:
Using biochemical and molecular biological techniques, we describe the expression of several key digestive enzymes throughout the ontogeny of larval haddock and Atlantic cod. The pattern of activity of general proteases (GP), trypsin-like enzymes (TLE), pepsin-like enzymes (PLE), general lipase (GL), bile salt-activated lipase (BAL), alkaline phosphatase (AP) and a-amylase were studied in larvae of both species using colourometric techniques. All enzymes were detected as early as hatch, except for a-amylase. Activity of GP generally increased from 0 to 144 degree-days (DD), decreased until 333 DD and then increased again in the oldest larvae of both species. Activity of TLE in haddock was high at hatch and generally showed an inverse pattern to that of Atlantic cod. Using zymography, we detected serine proteases, particularly trypsin, in the protein digestion of both species. Using RT-PCR, trypsinogen transcripts were detected as early as hatch. For both species, in situ hybridization analysis showed localization of trypsinogen expression to the pancreas during larval development. Although activity of PLE was detected as early as hatch in both species, pepsinogen transcripts were detected by RT-PCR only in the oldest larvae sampled, and after the gastric glands were identified morphologically. Atlantic cod BAL activity showed no significant differences over time. Activity of GL remained constant over time in larvae of both species. Levels of AP activity in haddock larvae showed no significant differences from hatch to 333 DD, except at 66 and 401 DD when there was a significant increase compared to other time points. In Atlantic cod, AP activity remained relatively constant until 476 DD, when a significant increase was detected. a-Amylase activity could not be detected in either species, except at 43 and 60 DD for Atlantic cod and 144 DD for haddock when large numbers of live prey were present in the gut. The estimated contribution of Pavlova lutheri-enriched rotifers to the total larval digestion was negligible, except for a-amylase, for which their contribution was estimated to be 100%. Our results suggest that both Atlantic cod and haddock larvae are capable of digesting protein and lipids at the time of mouth opening and that they have a limited capacity to digest carbohydrates.
(Institute for Marine Biosciences, National Research Council,
1411 Oxford Street, Halifax, Nova Scotia, Canada, B3H 3Z1; email of Harry Murray:
Harry.Murray@nrc.ca)
LEACHING PROPERTIES OF THREE DIFFERENT MICROPATICULATE DIETS
AND PREFERENCE OF THE DIETS IN COD (GADUS MORHUA L.) LARVAE
A. Kvåle, M. Yúfera, E. Nygård, K. Aursland, T. Harboe, K.
Hamre-2006
Aquaculture 251 (2-4): 402-415
Abstract:
Leakage of water soluble nutrients from larval microparticulated feeds is probably extensive and needs to be further investigated. Leaching rates of 14C-labelled serine, pepsin hydrolysed, protein enriched 14C-algae extract and intact protein enriched 14C-algae extract were measured from three microparticulated feeds for marine fish larvae (heat coagulated, protein bond feed; agglomerated feed; protein encapsulated feed). The effects of particle size (< 0.3 mm, 0.3–0.6 mm; 0.6–1.0 mm) and immersion time (1–60 min) in salt water were also tested. Leaching increased by decreasing molecular weight of leaching component (P < 10- 5), by the feeds in order encapsulated, heat coagulated and agglomerated feeds (P < 10- 5), by longer immersion time (P < 10- 5), and by decreasing feed particle size (P < 10- 5). Due to low protein content of the algae extract, the leaching rates of intact and hydrolysed algae extract did not represent absolute estimates for protein and hydrolysed protein leaching. A new estimate for leakage of hydrolysed protein was calculated based on molecular weight distribution of the hydrolysed algae extract analysed by cutoff centrifugation of the extract. Assuming that molecules < 300–600 or < 9–18 kD would leak, leakage of hydrolysed protein from the smallest feed particles after 5 min immersion would be 80–98%, 43–54% and 4–6% of the agglomerated, heat coagulated and protein encapsulated feeds, respectively. The feeds were also tested for preference in cod larvae of two different sizes (5.6 ± 2.5 mg and 15.8 ± 7.2 mg). The preference was highest for the heat coagulated feed in the first experiment (feed intake 0.32 ± 0.06 mg dry feed larvae- 1) and the agglomerated in the second (2.04 ± 0.32 mg dry feed larvae- 1), while the protein encapsulated feed was preferred at lower rates in both experiments (0.11–0.14 mg dry feed larvae- 1).
(National Institute of Nutrition and Seafood Research (NIFES),
P.O. Box 2029 Nordnes, 5817 Bergen, Norway; email of K. Hamre: Kristin.hamre@nifes.no)
BIOCHEMICAL, PHYSIOLOGICAL, AND IMMUNOLOGICAL CHANGES DURING
STARVATION IN JUVENILES OF LITOPENAEUS VANNAMEI
Cristina Pascual, Ariadna Sánchez, Edgar Zenteno, Gerard Cuzon, Gaxiola
Gabriela, Roberto Brito, Rolando Gelabert, Enrique Hidalgo, Carlos Rosas-2006,
Aquaculture 251 (2-4): 416-429
Abstract:
In an attempt to know how the protein level modulates catabolism and its effects on the immune response, we studied juvenile L. vannamei that had been starved for varying period after being conditioned on diet containing either maintenance or optimal dietary protein levels (DPL). The effect of dietary protein level on nutritional reserves management of shrimp and its relation with immune condition was also addressed. Juvenile shrimp were fed for 21 days on diets containing 5% and 40% dietary protein. Hemolymph metabolites (glucose, cholesterol, protein, acylglycerols, and lactate), hemocyanin, osmoregulatory capacity, digestive gland glycogen and lipids, and immune conditions (hemocytes characterization, phenoloxidase activity, respiratory burst: basal and activated) were evaluated and considered as initial condition. After that time, shrimp were starved for 21 days. During starvation time every 7 days nutritional, physiological and immunological condition were evaluated. A reduction in all physiological and immunological indicators was observed with starvation. The protein level of the conditioning diet had a significant effect on this response; generally, the effect was smaller with shrimp previously fed 40% dietary protein. In this sense the present results demonstrate that shrimp are well adapted to tolerate food deprivation for some time but that this tolerance is closely related to its previous nutritional condition. In the case of shrimp fed 40% DPL, wet weight, nutritional and immune condition was significantly affected after 14 days of starvation. In shrimp previously fed 5% DP, tolerance to starving condition was limited to only a few days (7 days) as a result of low reserves of circulatory and mussel proteins. All these results demonstrate that dietary protein levels can governor the immune condition of shrimp through the management reserves metabolism, indicating that a shrimp with a good nutritional condition can tolerate until 14 days without modifying the evaluated immune responses. In this sense it can be concluded that protein metabolism have a central role for shrimp.
(Unidad Multidisciplinaria de Docencia e Investigación,
Facultad de Ciencias, UNAM, Puerto de Abrigo s/n, Sisal, Mpo. Hunucmá,
Yucatán, México)
COMBINED EFFECTS OF FEEDING ENRICHED ROTIFERS AND ANTIBIOTIC
ADDITION ON PERFORMANCE OF STRIPED TRUMPETER (LATRIS LINEATA) LARVAE
S.C. Battaglene, D.T. Morehead, J.M. Cobcroft, P.D. Nichols, M.R. Brown, J.
Carson-2006
Aquaculture 251 (2-4): 456-471
Abstract:
Striped trumpeter have a complex and extended larval phase and are difficult to culture. Two experiments were conducted in replicated, 300-l hemispherical tanks to determine if larval survival, growth, bacterial or fatty acid profile were improved by feeding non-enriched rotifers or rotifers enriched with algae or commercially available products, as well as the effect of an antibiotic, oxytetracycline (OTC). Larvae were stocked at 25 l- 1 and 15 l- 1 and reared until Day 16 and Day 19 in Experiments 1 and 2, respectively. In Experiment 1, the feeding treatments were non-enriched rotifers, or rotifers enriched on algae, DHA Selco (a fish oil based emulsion) or RotiMac (dried Schizochytrium). There were no significant differences in mean survival (± SD) across treatments, which were generally low at 14.6 ± 5.2%. Larvae reared on rotifers fed DHA Selco and RotiMac, had significantly higher proportions of incorporated DHA but no significant increase in growth. In Experiment 2, larvae were fed rotifers enriched on DHA Selco or AlgaMac 2000 and reared with or without the daily addition of 25 mg l- 1 OTC. At Day 19, there was significantly higher survival for larvae reared on AlgaMac 2000 and OTC, (37.4 ± 5.6%), than DHA Selco and OTC, (16.0 ± 7.4%), AlgaMac 2000 without OTC (7.0 ± 8.0) and DHA Selco without OTC (3.3 ± 1.2). Larvae reared with OTC were larger (279 ± 58 µg and 7.4 ± 0.2 mm) than without OTC (177 ± 40 µg and 6.3 ± 0.2 mm). The addition of antibiotics did not significantly influence fatty acid profiles of larvae. There were no significant differences in the percentage of DHA, 27.6 ± 2.8%, EPA 4.6 ± 1.0% or ARA 4.9 ± 0.4%. Larvae reared with OTC had significantly less ‘grey gut’ (a measure of intestinal dysfunction). The results indicated that bacterial infection was a major source of mortality in striped trumpeter larvae and compromised larval growth. Assessment of the bacterial flora indicated that antibiotic use reduced the bacterial load, but did not eliminate potential pathogens. Our study suggests that microbial control has a greater influence than lipid nutrition on the survival and growth of larvae during the rotifer feeding stage.
(Marine Research Laboratories, Tasmanian Aquaculture and Fisheries
Institute and Aquafin Cooperative Research Centre, University of Tasmania, Private
Bag 49, Hobart, Tasmania, Australia, 7001; email of S. Battaglene: stephen.battaglene@utas.edu.au)
INFLUENCE OF LIPID LEVEL AND SUPPLEMENTAL LECITHIN IN DIET
ON GROWTH, FEED UTILIZATION AND BODY COMPOSITION OF JUVENILE FLOUNDER (PARALICHTHYS
OLIVACEUS) IN SUBOPTIMAL WATER TEMPERATURES
Kyoung-Duck Kim, Kyong-Min Kim, Kang-Woong Kim, Yong Jin Kang, Sang-Min Lee-2006
Aquaculture 251 (2-4): 484-490
Abstract:
This study was conducted to investigate the influence of dietary lipid level and supplemental soy lecithin on growth, feed utilization and body composition of juvenile flounder reared at two suboptimal water temperatures, 12 and 17 °C. Three isonitrogenous (CP 50%) diets containing 1% squid liver oil (S7), 7% squid liver oil (S14), and a mixture of 2% soy lecithin and 5% squid liver oil (SL14) were formulated to obtain 7% and 14% of crude lipid. Triplicate groups of fish (6.3 ± 0.2 g) were fed to apparent satiation twice a day for 60 days. Weight gain, daily feed intake, feed efficiency and protein efficiency ratio were significantly higher for fish reared at 17 °C than at 12 °C. Daily feed intake was significantly decreased with the increase of dietary lipid level at the same water temperature, but weight gain was not affected by dietary lipid composition. At 12 °C, feed efficiency and protein efficiency ratio were significantly higher for fish fed the S14 and SL14 diets than those of fish fed the S7 diet, while at 17 °C feed efficiency and protein efficiency ratio of fish fed the S14 diet, which were not significantly different from those of fish fed the SL14 diet, were significantly higher than those of fish fed the S7 diet. There were no significant effects of dietary lipid composition or temperature range on the whole body contents of moisture, crude protein, lipid or ash. Dietary lipid composition and temperature affected the fatty acid content of the polar lipid from the liver; and the n-3HUFA contents such as 20:5n-3 and 20:6n-3 were higher at 12 °C than at 17 °C. The results of this study indicate that an increase of dietary lipid level from 7% to 14% has beneficial effects on feed utilization of flounder when reared in suboptimal water temperatures. The increase of water temperature from 12 to 17 °C improved growth and feed utilization, but 2% soy lecithin had no substantial effect on growth and feed efficiency of juvenile flounder.
(Aquafeed Research Center, National Fisheries Research and
Development Institute, Pohang, 791-923, South Korea; email of K.D. Kim: kdkim@momaf.go.kr)
ENRICHMENT OF ARTEMIA NAUPLII IN ESSENTIAL FATTY ACIDS WITH
DIFFERENT TYPES OF LIPOSOMES AND THEIR USE IN THE REARING OF GILTHEAD SEA BREAM
(SPARUS AURATA) LARVAE
Óscar Monroig, Juan Carlos Navarro, Francisco Amat, Pedro González,
Azucena Bermejo, Francisco Hontoria-2006
Aquaculture 251 (2-4): 491-508
Abstract:
The present study aimed to optimize the enrichment protocols
of Artemia nauplii with highly unsaturated fatty acid liposomes. Three different
types of liposomes formulated with krill phospholipid extract were tested, using
a commercial emulsion as the control treatment. The incubation time of the nauplii
in the enrichment medium was chosen as the first variable studied. Total lipid,
lipid class and fatty acid profiles were analyzed in enriched nauplii after
18 and 21 h incubation in the enrichment media. A third sampling point at 24
h, where nauplii had been kept in clean seawater at 28 °C for 3 h, was established
to emulate potential changes in the nutritional value of the nauplii after some
hours in the larval rearing tank. A second objective of the study was the establishment
of a suitable liposome-based diet for the rearing of gilthead sea bream larvae,
as a model of marine fish.
Differences in the enrichment efficiencies through time were found not only
between liposome and emulsion based diets, but also among the different types
of liposomes. Whereas nauplii enriched with multilamellar vesicles and unilamellar
liposomes prepared by extrusion had maximum enrichment performance at 18 h of
incubation, nauplii enriched with unilamellar liposomes prepared by the detergent
solubilization method followed the enrichment pattern of the control emulsion,
with an optimal incubation period closer to 21 h. Analyses of the diets of the
larval nutrition trial seemed to confirm the results obtained in the first experiment,
although changes in certain variables occurred among the enrichments carried
out during the larval feeding trial. Biochemical characterization of body lipids
of the larvae indicated differences in total lipid and essential fatty acid
content, although no significant differences were found in growth and survival
of the larvae. Thiobarbituric acid reactive substances (TBARS), used to determine
the peroxide content of the larvae, indicated a significant higher content of
these compounds in larvae fed emulsion enriched nauplii compared to larvae fed
liposome enriched prey.
(Instituto de Acuicultura de Torre de la Sal (CSIC), 12595
Torre de la Sal. Castellón, Spain; email of O. Monroig: oscar@iats.csic.es)
INSTANTANEOUS EFFECT OF DIBROMOMETHANE ON METAMORPHOSIS OF
LARVAE OF THE SEA URCHINS STRONGYLOCENTROTUS NUDUS AND STRONGYLOCENTROTUS INTERMEDIUS
Yukio Agatsuma, Tetsuo Seki, Kazuya Kurata, Kazuya Taniguchi-2006
Aquaculture 251 (2-4): 549-557
Abstract:
A volatile chemical, dibromomethane (DBM), produced from red coralline algae is known as a chemical inducer of larval metamorphosis of the sea urchin Strongylocentrotus nudus. We performed experiments exposing DBM to the larvae of S. nudus and Strongylocentrotus intermedius through a hydrophobic membrane. Metamorphic rates resulting from different diluted DBM solutions and exposure times were ascertained. The highest metamorphic rate, more than 80% in both species, was found after 1 h exposure to 1/2 diluted DBM. With this dilution, more than 80% of S. nudus and S. intermedius larvae metamorphosed 1 h after start of the experiment after only 10 and 5 min exposure, respectively, which corresponded to the low concentrations of 52–61 ppm and 34–43 ppm DBM by GCMS analysis, respectively. These findings suggest that DBM has an instantaneous effect on high success of metamorphosis of larvae of S. nudus and S. intermedius.
(Graduate School of Agricultural Science, Tohoku University,
Tsutsumidori-amamiya, Aoba, Sendai, Miyagi 981-8555, Japan; email of Y. Agatsuma:
agatsuma@bios.tohoku.ac.jp)
5-HYDROXYTRYPTAMINE ENHANCES LARVAL DEVELOPMENT OF THE GIANT
FRESHWATER PRAWN, MACROBRACHIUM ROSENBERGII
Pawat Tangvuthipong, Praneet Damrongphol-2006
Aquaculture 251 (2-4) : 567-572
Abstract:
The effect of 5-hydroxytryptamine (5-HT) on larval development of the giant freshwater prawn, Macrobrachium rosenbergii, was investigated. Four days after hatching, larvae were exposed to 5, 50 or 100 µg/ml 5-HT in 12 ppt commercial seawater for a period of 2 or more days. Continuous exposure to 50 µg/ml or 100 µg/ml 5-HT over 2 days reduced the survival significantly and all larvae died by 13 days post-hatch (after 9 days of exposure). On the contrary, there was no significant difference in the survival of larvae exposed to various concentration of 5-HT for 2 days compared to that of the control. Exposure to 5-HT for 2 days stimulated growth and developmental rate of the larvae. Furthermore, pigmentation of the exoskeleton was also induced within 1 h of exposure. The larvae exhibited bright-orange color on their eyestalks, cephalothoraxes and abdomens. Exposure to 100 µg/ml 5-HT for 2 days produced the highest growth, developmental rate and the strongest pigmentation. The average body lengths 25 days post-hatch of larvae exposed to 50 µg/ml and 100 µg/ml 5-HT for 2 days were 3.5 ± 0.6 mm and 4.3 ± 0.7 mm, respectively, compared to 2.8 ± 0.4 mm that of the control. Furthermore, the rate of transformation of larvae to postlarvae during 30–40 days post-hatch was significantly higher in those exposed to 50 µg/ml and 100 µg/ml 5-HT compared to that of the control. The present study indicates that brief exposure of early stage larvae to 50–100 µg/ml 5-HT enhances growth, developmental rate and pigmentation of the giant freshwater prawn larvae.
(Department of Biology, Faculty of Science, Mahidol University,
Bangkok 10400, Thailand; email of Praneet Damrongphol : scpdr@mahidol.ac.th)
VARIATIONS ON DEVELOPMENT AND STRESS DEFENCES IN SOLEA SENEGALENSIS
LARVAE FED ON LIVE AND MICROENCAPSULATED DIETS
C. Fernández-Díaza, J. Kopeck, J.P. Cañavate, C. Sarasquete,
M. Soléa-2006
Aquaculture 251 (2-4): 573-584
Abstract:
Growth, development, antioxidant enzymes, stress proteins (HSP70 and HSP60), lipid peroxidation (LP) and histology in Solea senegalensis larvae were followed from 8 to 30 days post hatching (dph). Larvae were fed on three different diets: (1) live Artemia nauplii, (2) microcapsules elaborated by internal gelation, (MA) and (3) these same microcapsules but 10-fold supplemented with vitamin A (MAV). The Artemia fed group showed higher growth and a faster metamorphosis than the ones fed with microencapsulated diets, although all had similarly high survival rates of 80%. Vitamin A (VA) supplementation improved growth and development from 15 dph in relation to the strictly inert diet (MA). Larvae fed with Artemia showed organs and tissues with a normal pattern of development, whereas histological alterations were seen in larvae fed with both inert diets. The antioxidant enzymes: catalase (KAT), superoxide dismutase (SOD), and total glutathione peroxidase (t-GPX) as well as LP levels and stress proteins (HSP70 but not HSP60), measured in whole larvae, showed diet and age dependence in their response. Larvae fed with both inert diets showed similar biomarker activities, but these activities were different (p < 0.05) from larvae fed with Artemia. That is, KAT and HSP70 were lower in larvae fed with live prey and t-GPX and LP levels were lower in larvae fed with the inert food. Among the factors responsible for increased antioxidant defenses were the initiation of metamorphosis and the use of inert food. This study suggests the usefulness of the biomarkers selected as tools to evaluate the effects of compound diets on larvae.
(Instituto de Ciencias Marinas de Andalucía (CSIC).
Campus Río San Pedro, 11510 Puerto Real, Cádiz, Spain; email of
Catalina Fernandez: catalina.fernandez@icman.csic.es)
STUDIES ON SPERM OF DIPLOID AND TRIPLOID TENCH, TINCA TINCA
(L.)
Otomar Linhart, Marek Rodina, Martin Flajshans, Nicola Mavrodiev, Jana Nebesarova,
David Gela, Martin Kocour-2006
Aquaculture International 14 (1-2): 9 - 25
Abstract:
The tench Tinca tinca is an interesting fish from the viewpoint of polyploidy and related atypical reproduction aspects. Triploid tench were produced artificially. Studies of spermiation as well as of sperm motility and structure were performed on several triploid and diploid males simultaneously with individual experimental crosses with diploid females to define their reproductive capacities. The testes of triploids visually looked less developed in the most of cases with lower sperm production (0.05 cm3 sperm per male), GSI and weight of testes compared to diploids (0.58 cm3 sperm per male). Analysis of variance showed significant influence of ploidy level on the percentage of motile spermatozoa. Triploidy did not change percentage of live spermatozoa and velocity of spermatozoa at the first time of sperm movement. The study of sperm structure by scanning electron microscopy revealed that most sperm cells were of normal structure with some anomalies. Sperm heads of triploid and diploid males were mostly round-shaped, 1.86±0.2 and 1.6±0.18 µm in diameter. The midpiece of triploid spermatozoa was slightly narrower than that of diploid ones with typical cylindrical shape. Flow cytometry revealed sperm cells of triploids to be largely aneuploid (1.47 n) with high mosaic DNA, oscillating from haploid DNA content (1.0 n) to diploid DNA content (1.9 n). Experimental crosses between triploid males and diploid females revealed that these males were capable to stimulate effective development with relatively high level of fertilization and hatching rates from 0 to 70%. In conclusion, triploidization does not seem to guarantee sterility of tench.
(Joint Laboratory of Genetics, Physiology and Reproduction
of Fish, University of South Bohemia, Research Institute of Fish Culture and
Hydrobiology, 38925 Vodnany, Czech Republic; email of Otomar Linhart: linhart@vurh.jcu.cz)
RECIPROCAL HYBRIDS OF TENCH TINCA TINCA (L.) × BREAM
ABRAMIS BRAMA (L.), AND TENCH × CARP CYPRINUS CARPIO L., AND SOME CHARACTERISTICS
OF THEIR EARLY DEVELOPMENT
Andrzej Mamcarz, Dariusz Kucharczyk, Roman Kujawa-2006
Aquaculture International 14 (1-2): 27 - 33
Abstract:
Reciprocal hybrids between tench Tinca tinca (L.) and carp Cyprinus carpio L., and tench and bream Abramis brama (L.) were produced artificially. The survival of all these hybrids during embryogenesis was quite high. The highest survival rate (over 60%) at the eyed stage was observed for tench and bream hybrids (both sex combinations). The hatching rates of these hybrids were also over 60%. The number of larvae with some abnormalities (i.e. deformed body) was low. In contrast, the hatching rates of tench and carp hybrids were very low (0.2%). From over 1000 fertilized eggs, only three specimens started swimming, and only one specimen survived to juvenile stage. Embryos of hybrids and their parental species differ in morphological features. These differences were also visible in the juveniles. Body parameters of juvenile hybrids produced from three species had intermediate values in comparison to parental fish.
(Department of Lake and River Fisheries, University of Warmia
and Mazury in Olsztyn, Oczapowskiego 5, 10-957 Olsztyn, Poland; email of Andrzej
Mamcarz: mamcarz@uwm.edu.pl)
INSEMINATION, FERTILIZATION AND GAMETE MANAGEMENT IN TENCH,
TINCA TINCA (L.)
Otomar Linhart, Marek Rodina, Martin Kocour, David Gela-2006
Aquaculture International 14 (1-2): 61 - 73
Abstract:
Various procedures for artificial insemination in tench, Tinca tinca (L.) were re-examined with evaluation of fecundity of males and females among different tench strains. The objectives of this study were to enhance fertilization and hatching rates through optimization of the activation solution, the insemination process, the activation of gametes, and the elimination of eggs stickiness. Sperm for all experiments was collected directly into immobilization solution of modified Kurokura solution containing 180 mM of NaCl and stored at 2 °C for 2.5–5 h prior to the experiment. When dechlorinated tap water was used for activation a gamete ratio of 1150 spermatozoa per egg showed the best significant fertilisation and hatching rates. Optimal ratio between eggs (weight in g) and activation solution (in cm3) was 1:1. Different concentrations of activation solutions such as NaCl from 0 to 68 mM (0–136 mOsmol kg-1) without buffer statistically decreased fertilization and hatching rates. The activation solution containing 17 mM of NaCl, 10 mM Tris–HCl, pH 8 and 9 significantly increased fertilization and hatching rates compared to dechlorinated tap water of pH 7 or activation solution containing 17 mM of NaCl, 10 mM Tris–HCl, pH 6 and 7. Adhesiveness of the eggs was successfully removed by incubation in Alcalase and activity: 3.16 Anson units per cm3.
(Joint Laboratory of Genetics, Physiology and Reproduction
of Fish, Institute of Animal Physiology and Genetics, Academy of Sciences of
the Czech Republic, University of South Bohemia, Research Institute of Fish
Culture and Hydrobiology, 38925 Vodnany, Czech Republic; email of Otomar Linhart:
linhart@vurh.jcu.cz )
QUANTITY, MOTILITY AND FERTILITY OF TENCH TINCA TINCA (L.)
SPERM IN RELATION TO LHRH ANALOGUE AND CARP PITUITARY TREATMENTS
Nicolas Caille, Marek Rodina, Martin Kocour, David Gela, Martin Flajšhans,
Otomar Linhart-2006
Aquaculture International 14 (1-2): 75 - 87
Abstract:
The spermiation of tench males was stimulated with Supergestran containing mammalian LHRHa lecireline at the following doses: 5, 10, 20 and 40 g kg-1 b.w.; then with carp pituitary suspension (CPS) at a dose of 2 mg kg-1 b.w. and with a control of saline physiological solution. The following days, meaning 24, 48 and 72 h after injection, sperm was collected to evaluate volume and the number of sperm per male per kg body weight (B.W.) The percentage of motile sperm and velocity of spermatozoa were measured 48 h after hormonal injection, and 72 h after hormonal injection the sperm was evaluated for fertilization and hatching ability. All 42 males in experimental groups were diploid. Live weight did not differ significantly among experimental groups. The strongest stimulation of spermiation was achieved with LHRHa in dosage of 20 and 40 g kg-1 b.w. and CPS compared to males of the control group and lower dosage of LHRHa. Analysis of variance showed no significant influence of the treatment on the velocity and percentage of motile spermatozoa. The effect of different treatment on the fertilization capacity (the number of spermatozoa per egg was equilibrated) was significant. Significantly the highest quality of sperm collected 72 h after injection expressed by percentage of fertilization and hatching (62–65% fertilization and 61–64% hatching rates, respectively) was found for LHRHa in dosage of 20 and 40 g kg-1 b.w. Significantly the lowest parameters of fertilization and hatching were found for the control group, on the 12% level.
(Joint Laboratory of Genetics, Physiology and Reproduction
of Fish, Institute of Animal Physiology and Genetics, Academy of Sciences of
the Czech Republic, University of South Bohemia, Research Institute of Fish
Culture and Hydrobiology, 38925 Vodnany, Czech Republic; email of Otomar Linhart
: linhart@vurh.jcu.cz)
TENCH (TINCA TINCA) BROODSTOCK MANAGEMENT IN BREEDING STATION
UNDER CONDITIONS OF POND CULTURE: A REVIEW
David Gela, Martin Flajšhans, Martin Kocour, Marek Rodina, Otomar Linhart-2006
Aquaculture International 14 (1-2): 195 - 202
Abstract:
A basic assumption for carrying out the breeding work is to have well-organised broodstock management. Taking into account the number of populations bred and the limited number of ponds available, it is impossible to avoid rearing several juvenile or adult breeds in mixed stocks. Fish of individual breeds are group-marked with regular renewal of the freeze-branded mark and broodstock adults should be marked individually. To minimise inbreeding or losses in genetic variation, at least 120 fish per strain are reared and when the strain is restored, factorial crosses of at least 15 females and 25 males should be applied. All activities are individually registered in the “Evidence 2003” data-recording software and data can be sorted by the origin of the fish population, of the strain or of individual fish; reproductive and performance parameters are recorded individually also. Further breeding operations with tench comprise the selection after over-wintering and rearing of fish before, during and after the reproductive season.
( Joint Laboratory of Genetics, Physiology and Reproduction
of Fish of IAPG, Academy of Sciences of the Czech Republic and University of
South Bohemia, Vodnany, 38925, RIFCH, Czech Republic; email of David Gela: gela@vurh.jcu.cz)
EFFECTS OF CRUSHED CONSPECIFICS ON GROWTH AND SURVIVAL OF PENAEUS
MONODON FABRICIUS POST LARVAE
Bui Tui Nga, Miquel Lürling, Edwin Peeters, Rudil Roijackers, Marten Scheffer,
Truong Trong Nghia-2006
Aquaculture Research 37 (3): 224-
Abstract:
In the present study, the hypothesis tested was that Penaeus monodon post-larvae (PL) experience lower growth when exposed to crushed conspecifics, which was achieved by exposing individual P. monodon PL with abundant food for 4 weeks to a gradient from 0 to 100 crushed conspecific PL L1. Both dry weight (48.5±7.2 mg) and body size (28.0±1.3 mm) of animals exposed to 1 macerated PL L1 were significantly (P=0.011) higher than those of animals in treatments with 0, 5 and 10 crushed PL L1 (average over treatments: 25.6±3.2 mg; 23.4±0.5 mm). All animals died within 1 week when exposed to 70 and 100 crushed PL L1, and within 3–4 weeks when exposed to 50 and 30 crushed PL L1. Exposure time affected mortality and it appeared that LC50 values decreased from 60 to 13 crushed PL L1 from 1 to 4 weeks' exposure. Survival of P. monodon PL was negatively correlated to pH, biological oxygen demand, ammonia and nitrate. In conclusion, low dose of crushed conspecifics has a stimulatory effect on P. monodon PL, as larvae were heavier and larger, while high doses cause high mortality.
(Department of Environmental and Natural Resources Management,
College of Agriculture, Cantho University, Cantho, Vietnam; email of M Lürling:
miquel.lurling@wur.nl)
ARTIFICIAL SPAWNING OF FEMALE LITHUANIAN STRAIN B CARP (CYPRINUS
CARPIO L.) AFTER TREATMENT WITH CARP PITUITARY HOMOGENATE, Ovopel or [d-Tle6,
ProNHEt9] GnRH-a (Lecirelin)
E. Brzuska-2006
Aquaculture Research 37 (3): 264 -
Abstract :
The results of reproduction of females from Lithuanian strain B carp after ovulation stimulation with carp pituitary homogenate (CPH; 0.3+2.7 mg kg1; group I), Ovopel (1/5+1 pellet kg1; group II) or [d-Tle6, ProNHEt9] GnRH-a (Lecirelin) with metoclopramide (15 µg kg1+10 mg kg1 respectively; group III) were investigated. The lowest percentage of spawning females (71%) was recorded in the group treated with CPH. In case of Ovopel or Lecirelin induced ovulation, 86% of females spawned. No statistically significant effect of the ovulation stimulator (group) on the weight of eggs was found; however, the highest mean weight of eggs (expressed both in grams and in the percentage of female body weight) was recorded for the group treated with Ovopel (1400 g and 13%). After the treatment with CPH or Lecirelin, the weight of eggs was 1140 g (11%) and 1100 g (10%) respectively. The ovulation stimulator significantly affected the percentage of live embryos after 36 and 48 h incubation of eggs (P=0.05; P=0.01). After treatment with [d-Tle6, ProNHEt9] GnRH-a, eggs of the best quality were obtained and after 36 and 48 h incubation the mean percentages of live embryos were significantly higher than the means calculated for the remaining two groups. No statistically significant differences were found between the percentage of living embryos after 36 and 48 h incubation of groups I and II.
(Polish Academy of Sciences, Institute of Ichthyobiology and
Aquaculture, Golysz 43-520, Chybie, Poland.; email of E. Brzuska: golysz@fish.com.pl,
zigr@bb.onet.pl)
COMPARATIVE UTILITY OF EGG BLASTOMERE MORPHOLOGY AND LIPID
BIOCHEMISTRY FOR PREDICTION OF HATCHING SUCCESS IN ATLANTIC COD, GADUS MORHUA
L.
Randy W. Penney, Pauline L. Lush, Joy Wade, Joseph A. Brown, Christopher C.
Parrish, Margaret P. M Burton-2006
Aquaculture Research 37 (3):
Abstract :
Six blastomere morphology parameters indicative of cell development abnormalities, egg diameter, dry weight, total lipid, lipid classes and fatty acids were determined for egg batches collected daily from three Atlantic cod (Gadus morhua) broodstock groups over the course of one spawning season. Egg batches were incubated to hatch and each morphological and biochemical parameter was tested as a predictor of hatching success. Five of the six blastomere morphology parameters were significantly positively correlated with each other. Correlation coefficients among several fatty acid parameters were also significant but correlation coefficients among the various lipid classes were mostly not significant. No significant correlations were found between blastomere morphology and lipid class or fatty acid parameters. Egg dry weight was negatively correlated with cell clarity, %docosahexanoic acid (DHA), DHA:eicosapentaenoic acid, and S polyunsaturated fatty acids. Fertilization success was not significantly correlated with any of the morphology or biochemistry parameters. Within-population variability in several morphological and fatty acid parameters was related to elapsed time since onset of first spawning. However, the occurrence of such relationships with elapsed time was highly variable and inconsistent among the three broodstocks, typically being significant for only one or two broodstocks but not all three. Mean hatching success rates were high (>75%) in all three broodstocks but hatching success was not significantly related to any of the morphological or biochemical parameters nor to elapsed time from onset of first spawning. The implications of these results are discussed in terms of the utility of the various morphology and biochemistry parameters as measures of egg quality in marine finfish hatcheries.
(Fisheries and Oceans Canada, PO Box 5667, St John's, NL, Canada
A1C 5X1; email of R. Penney: penneyra@dfo-mpo.gc.ca)
SHORT COMMUNICATION:
GONADAL DEVELOPMENT IN HYBRIDS OF MEDITERRANEAN SPARIDS: SPARUS AURATA (FEMALE)
×PAGRUS PAGRUS (MALE)
Michael Pavlidis, Lambros Kokokiris, Michael Paspatis, Stylianos Somarakis,
Maroudio Kentouri, Pascal Divanach-2006
Aquaculture Research 37 (3): 302 -
(Department of Biology, University of Crete, Heraklion, Greece; email of L.
Kokokiris: lamprosk@spark.net.gr)
SHORT COMMUNICATION:
DOES MALPIGMENTATION IMPROVE GROWTH IN JUVENILE TURBOT (SCOPHTHALMUS MAXIMUS
RAFINESQUE) AND HALIBUT (HIPPOGLOSSUS HIPPOGLOSSUS L.)?
Albert K Imsland, Trond Wergeland, Thor M Jonassen, Sigurd O Stefansson-2006
Aquaculture Research 37 (3): 306-
(Akvaplan-niva Iceland Office, Akralind 4, 201 Kópavogur, Iceland, email
of A. Imsland: albert.imsland@akvaplan.niva.no)
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