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1.
There are few studies on flow fields generated by aerators in fish larvae rearing tanks. The flow varies with aeration rates and tank proportions resulting in different larvae survival rates. The effects of aeration rate and aspect ratio AR (the ratio of liquid depth to tank radius) on overall flow patterns were investigated experimentally using flow visualization techniques. Two distinct types of flow patterns, a single-pair vortex system and a two-pair vortex system, were observed as the value of tank aspect ratio varied from about 1.0 to 2.0. In addition, corner vortex structures were observed in both the region between the free surface and the upper sidewall, and between the bottom wall and the lower sidewall of the tank. On the sidewall, reattachment and separation points were found, which were closely related with these vortex structures. 相似文献
2.
Dietary essentiality of ascorbic acid in rohu larvae: Quantification with ascorbic acid enriched zooplankton 总被引：2，自引：0，他引：2
Carp larvae, like any other fish larvae dependon natural food during first few days of theirlife. In nursery conditions, high mortality andslow larval growth are of common occurrence;sub-optimal nutrition might be a possiblereason for such consequences. To improve thesituation the effect of feeding ascorbicacid-enriched live food on survival, growth,tissue biochemical composition includingascorbate level was evaluated in first feeding(3 days old) larvae (av. wt. 2.2 mg) of therohu carp, Labeo rohita (Ham.) for aperiod of 15 days (temp. 28.6 ± 1 °C)under natural photoperiod. The larvae (stockingdensity 10 l–1) were offered enriched andnon-enriched zooplankton ad libitumfollowing a rigid schedule with four feedingregimes, each having 3 replicates. In treatmentT1, non-enriched zooplankton (Moina,Daphnia, Cyclops, Diaptomus) and in T2,T3, T4 ascorbic acid enriched (12 henrichment) zooplankton [@10%, 20% and 30%ascorbyl palmitate (AP) inclusion in diet ofzooplankton] were offered. Highest survival(90%) and growth (9563% live weight gain)could be seen in T3 group and the lowestin T1 (62% survival and 805% live weightgain), thus confirming the dietary essentialityof ascorbic acid for rohu larvae. Therequirement has been shown to be 1409 µg/gdry diet. Whole body tissue analyses for crudeprotein, total lipid and RNA: DNA ratiofollowed the same trend as that of growthresponse and percent survival. Significantpositive correlation (r = 0.949 and 0.861) couldbe found with muscle RNA/DNA ratio and muscleRNA content with specific growth rate indifferent treatments. Significant differencewas found in tissue ascorbate levels betweenenriched plankton fed groups, being highest in T3. Such live foodmediated vitamin transfer might be an effectivemeans to provide higher plane of nutrition forhigh survival and rapid growth for rohu larva. 相似文献
3.
E. Zaniboni-Filho A. P. O. Nuñer D. A. Reynalte-Tataje R. L. Serafini 《Fish physiology and biochemistry》2009,35(1):151-155
The present study aimed to determine the influence of water pH on survival of curimbatá, Prochilodus lineatus, larvae. Forty-five 2-l glass aquaria with artificial aeration and no water exchange were stocked at a density of 10 larvae
l−1. The pH values used as treatments were 3.7 ± 0.0, 4.0 ± 0.0, 4.4 ± 0.2, 4.6 ± 0.2, 4.8 ± 0.2, 5.1 ± 0.2, 5.3 ± 0.2, 5.6 ± 0.2,
7.2 ± 0.2, 8.7 ± 0.4, 9.0 ± 0.4, 9.2 ± 0.4, 9.4 ± 0.6, 9.7 ± 0.5 and 10.0 ± 0.5 in a completely random experimental design
with three repetitions. Water pH was maintained by the addition of NaOH or H2SO4 solutions. After 72 h of experiment, no survival was registered at pH below 4.6, 1.5% survival at pH 4.6, and about 50% survival
at pH 9.4 and above. Survival rates between 70 and 80% were registered at pH 4.8–5.6 and at pH 7.2, whereas over 90% survival
was registered at pH between 8.7 and 9.2. 相似文献
4.
Two groups of Senegal sole (Solea senegalensis) larvae were cultured. One used rotifers for the first 10 days after hatching (dph) and enriched Artemia metanauplii from 6 to 30 dph and the other without rotifers, using enriched Artemia metanauplii as the sole food source. The quantity of metanauplii used was the same (group A), twice (group A2) and three times (group A3) the quantity of live prey (in dry weight) of the group fed with rotifers (group R). At the end of the experiment, the growth, in terms of total length and individual dry weight was significantly higher for the larvae on group A2 whilst rotifer fed larvae (R) showed the poorest results. Eye migration was also delayed by approximately 2 days in the group R. No significant differences were found in survival rates. The influence of diet on Senegal sole metamorphosis and its relationship with the size rather than the age of the fish are discussed. 相似文献
5.
Poor swimbladder inflation leads to low fish survival due to resulting spinal deformities and the inability to feed and develop normally. Failure of swimbladder inflation may be attributed to the inappropriate range of abiotic conditions. This study investigated the effects of temperature, light source and intensity, and oxygen conditions on initial swimbladder inflation, growth and survival of yellowtail kingfish Seriola lalandi larvae. The study consisted of four separate trials including low (21.5°C) and high (24.5°C) temperatures, natural and artificial light sources, low (1000 lux) and high (32 000 lux) light intensities, and ambient and supersaturated dissolved oxygen. Initial swimbladder inflation was only significantly affected by light source, with the highest inflation rate (97.5 ± 3.5%) under artificial light. Fish growth was improved at the higher temperature and at the higher light intensity. Survival was only significantly influenced by light intensity, with the highest survival (11.0 ± 2.3%) at the high intensity (32 000 lux). This study indicates that light source affects swimbladder inflation timing and high artificial light intensity improves larval fish growth and survival. 相似文献
6.
T. Citarasu K. Venkatramalingam M. Micheal Babu R. Raja Jeya Sekar M. Petermarian 《Aquaculture International》2003,11(6):581-595
The indiscriminate use of antibiotics and chemicals in shrimp hatcheries has led to biomagnification and that in turn could
lead to rejection of a whole consignment. The application of the bioencapsulation technique as a tool for curative treatment
in shrimp larvae was investigated. Herbs having antibacterial properties such as Solanum trilobatum, Andrographis paniculata and Psoralea corylifolia (methanolic extracts) were bioencapsulated in Artemia and fed to Penaeus monodon post larvae PL 1–25. The post larvae were reared in a medium inoculated with pathogenic bacteria such as Pseudomonas aeruginosa, Staphylococcus aureus, Salmonella typhi and Vibrio sp. Post larvae reared in the non-inoculated water and fed with non-enriched Artemia exhibited 90% survival, highest specific growth rate (12.43%) and reduced bacterial load. P. monodon reared in the bacterial inoculated water and fed with the non-enriched Artemia exhibited the lowest survival (10–30%), specific growth rate (8.42–9.1%) and increased bacterial load (2.86 × 103 to 3.76 × 105 cfu/g). The methanolic extracts of the herbs helped to increase survival and specific growth rate and reduced bacterial load
in the P. monodon culture system. Among the three herbal extracts, P. corylifolia enriched Artemia fed post larvae showed the tendency to higher survival (>50%), growth rate (11.5 averaged) and low bacterial load (1.12 × 105 cfu/g).
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
7.
Jenny Rodríguez Yuri Espinosa Gabriela Cárdenas Samuel Stern 《Aquaculture (Amsterdam, Netherlands)》2007,273(4):405-415
The effect of the inclusion of probiotics (Vibrio alginolyticus) and β-1,3/1,6-glucans in Penaeus vannamei larviculture was evaluated by measuring the immune response and survival of shrimp juveniles subjected to white spot syndrome virus (WSSV) challenge tests (per os) and pond culture. Treatments were designed to contrast the probiotic factor (inclusion vs non-inclusion) and β-1,3/1,6-glucans supplementation in various larvae stages; starting from early stage (Zoea II), to middle stage (PL 12), late stage (15 days pre-challenge) or non-supplemented. In larviculture, the highest survival was obtained in animals treated with β-1,3/1,6-glucans from Zoea II. The use of probiotics enhanced survival during the first 0-52 h post-WSSV challenge period. During 56-156 h post-WSSV challenge period, interactions were observed between β-1,3/1,6-glucans × time and β-1,3/1,6-glucans × time × probiotics. Significant differences in final survival rates between treatments were not observed. In the second WSSV challenge, immune parameters were analysed. Significant interaction between probiotics and β-1,3/1,6-glucans was observed for plasmatic protein (PP) concentration, super oxide anion (O2−) generation, antibacterial activity (AA), and total haemocyte count (THC). The use of probiotics in larviculture had a negative effect on the PP, but increased the AA and THC, while β-1,3/1,6-glucans had a negative effect on the O2− generation. The most relevant results were obtained from treatments T2 (probiotics in larviculture, β-1,3/1,6-glucans from Z II) and T4 (probiotics in larviculture, β-1,3/1,6-glucans 15 days before challenge). Treatment T2 presented the highest survival rate in larviculture. After WSSV infection, the animals of this treatment displayed resistance to the virus, a strong AA and increase of THC. Treatment T4 increased the amount of PP, increased the O2− generation and THC. Histological analysis showed that the animals of treatment T2 and T4 were able to limit the spread of the virus during the first hour after challenge with WSSV. The survivors from treatments T2 and T4 had a high THC, accompanied by a lack of white spot disease (WSD) injuries. A bioassay was carried out under farm conditions during the warm-rainy season using larvae from treatments T2 and T4. The animals were stocked at 18 animals/m2 in earth ponds of 0.20 ha (three ponds/larvae kind). WSD outbreak was not detected, and the survival was significantly higher in ponds stocked with larvae from treatment T4 (70 ± 3%) than in ponds stocked with larvae from treatment T2 (49 ± 9%). 相似文献
8.
Two experiments were carried out to test microparticulate diets forweaning hatchery-produced larvae and juveniles of bullseye pufferSphoeroides annulatus. The diets were formulated with differentprotein sources: diet 1 with a combination of decapsulated cysts ofArtemia and fishmeal, and diet 2 with a combination offishmeal, squid, tuna gonad and shrimp meal. In the first experiment60-days-old fish were weaned with the microdiets over five days. Fishsurvival after 11 weeks of feeding was 92% for diet 1, 85%for diet 2, and 95% for the control fish fed Artemianauplii. Once it was determined that bullseye puffer can be adequatelyreared with artificial dry diets, diet 1 was used to test earlier timesfor weaning to reduce the period of Artemia feeding. In thesecond experiment, three different times were tested for initiation ofweaning in sibling fish larvae, i.e., at 29, 34, and 39 days post-hatch.Small differences in weight, length and survival were found amongweaning treatments after 23 days of feeding. When weaned at day 29post-hatch, fish larvae grew from an initial weight of 38.4 mg andlength of 11.1 mm to a final weight and length of 405.7 mg and 25.1 mmrespectively. Final survival in this treatment was 49.3%. Thereduced period of Artemia feeding would provide an economicalalternative for the species to take into consideration for its cultureat commercial scale. 相似文献
9.
Armando García-Ortega 《Fish physiology and biochemistry》2009,35(1):69-80
The spotted rose snapper (Lutjanus guttatus) and bullseye puffer (Sphoeroides annulatus) are fish species from the tropical Eastern Pacific for which controlled production of larvae and juveniles has been accomplished
in recent years. Diverse topics relating to their biology and aquaculture production are currently under study, in particular
the nutrition and feeding aspects required to formulate practical feeds and rearing protocols. Improvements in larval growth
and survival are possible by feeding live food organisms with natural or enhanced essential fatty acids content and highly
digestible artificial microdiets. The ontogeny of the digestive tract and the expression and activity of digestive enzymes
have been described for S. annulatus larvae. The effect of various protein and lipid levels on growth and feed utilization has been studied in juvenile and on-growing
fish. Both species have carnivorous feeding habits and require high levels of protein in their diets, from 40% to 45% (dry
weight) in spotted rose snapper and above 50% in bullseye puffer, with the younger stages requiring the highest protein levels.
Encouraging results have been obtained in feeding experiments with different sources of dietary protein from animal and plant
origin to evaluate their suitability as feed ingredients in practical diets. Optimization of fish culture practices through
feeding management has also been investigated. Trials with various fish densities and feeding frequencies in intensive culture
systems are providing information to improve feed utilization and growth in on-growing fish. Further research is underway
to evaluate factors in broodstock nutrition which have an impact on egg and larval quality, and into the use of various commercially
available oil sources in on-growing diets. In this paper, the results on nutrition and feeding research with both species
are reviewed and research needs to support their commercial production in the region are discussed. 相似文献
10.
Larvae of the freshwater prawn (Macrobrachium rosenbergii) were reared to post-larvae in a closed recirculation system. Six treatments were designed where freshly-hatched Artemia nauplii were first given to the larvae for 3, 7, 11, 15, 17 and 25 days according to the treatment. After that (-3) HUFA-enriched Artemia were given until the 28th day at which time the test was terminated and evaluated. The requirement for (-3) Highly Unsaturated Fatty Acids (HUFA) for the larval stages of M. rosenbergii was confirmed by this experiment. Moreover, the longer the period of feeding on (-3) HUFA-enriched Artemia nauplii, the better the results in terms of growth, metamorphosis rate, survival and stress resistance. 相似文献