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1.
We monitored feeding behavior and survival of starved juvenile olive flounder experimentally infected with the gill monogenean
Neoheterobothrium hirame. Infected flounder increased amount of the time spent in the water column by 117% when trying to capture live mysids, Neomysis sp. They also showed different feeding patterns from those of uninfected fish and made fewer attacks towards prey during
one feeding attempt. Although the average numbers of mysids captured by individuals were similar between infected and uninfected
fish, heavily infected fish tended to catch less prey. These results indicate that N. hirame reduces the feeding efficiency of the host for capturing live prey and possibly makes them more vulnerable to predation during
feeding. We could not detect any obvious difference in survival rates between uninfected, lightly and heavily infected fish
during 3 months of starvation. There was no evidence that starvation makes fish more susceptible to N. hirame. The present study provides first experimental evidence that N. hirame affects feeding behavior of juvenile olive flounder and supports the idea that this parasite indirectly reducing the host’s
survival and may be responsible for the recent reduction of the flounder population in Japan. 相似文献
2.
3.
In this study, four essential oils—cinnamon oil, leech lime oil, lemongrass oil, and turmeric oil—were examined for their
antimicrobial activities against Streptococcus iniae, a bacterium that is pathogenic in fish, in which it causes streptococcosis. Cinnamon oil was the most potent antimicrobial
agent among these oils, with a minimal inhibitory concentration (MIC) of 40 μg/ml. By using gas chromatography–mass spectrometry
(GC–MS), it was found that the major components of cinnamon oil were cinnamaldehyde (90.24), limonene (2.42%), cinnamyl acetate
(2.03%), linalool (1.16%), and α-terpineol (0.87%). Of these compounds, only cinnamaldehyde exhibited antimicrobial activity
against S. iniae, with an MIC of 20 μg/ml. In an in vivo trial, no mortality was apparent in fish fed on fish diets supplemented with 0.4%
(w/w) of cinnamon oil and with 0.1% (w/w) of oxytetracycline 5 days prior to infection with S. iniae. These results indicate that cinnamon oil had a protective effect on experimental S. iniae infection in tilapia, and thus has the potential to replace the antibiotics used to control this disease. 相似文献
4.
The ability of an algicidal bacterium Marinobacter salsuginis strain BS2, isolated from shrimp pond water, to reduce shrimp mortality was investigated under laboratory conditions. When
two species of shrimp (Penaeus monodon and Litopenaeus vannamei) (body length 1.5–1.8 cm) were cultured together with the dinoflagellate Noctiluca scintillans, nearly 80 % of the shrimps died within 7 days. However, when bacterial strain BS2 was also added to the culture, N. scintillans was killed within 48 h, and shrimp survival rates on the 7th day improved from 23 to 87 % for both P. monodon and L. vannamei. The bacterium BS2 alone had no effect on shrimp condition. Under conditions of increased dissolved oxygen, the effect of
using BS2 was greater, and shrimp survival rates improved even more dramatically, from 26 to 98 %. These studies provide the
first evidence that the use of killing bacteria, isolated from shrimp culture water, can suppress harmful algal blooms (HABs)
and thus restore the efficiency of shrimp production. The control of HABs in this way in shrimp culture farms would be a major
benefit for shrimp production. 相似文献
5.
The effect of aqueous extract of Cratoxylum formosum on innate immune response and disease resistance in tilapia Oreochromis niloticus was investigated. The fish were fed diets containing 0% (control), 0.5% (diet 1), 1% (diet 2), and 1.5% (diet 3) of C. formosum aqueous extract for 30 days. At the end of the experimental period, parameters of innate immune response including phagocytosis
of blood leukocytes, lysozyme activity in plasma, and respiratory bust activity were examined. Feeding the fish with diet
2 and diet 3 for 20 days enhanced phagocytic activity and for 30 days stimulated lysozyme and respiratory burst activities.
Diet 1 increased the phagocytic activity at 30 days, but did not affect the other measured parameters. All parameters were
not significantly changed (P > 0.05) in the control group throughout the experiment. Following 30 days of feeding, fish were infected with S. agalactiae. The cumulative mortalities of bacterial-infected tilapia that were fed diet 1, diet 2, and diet 3 were 56, 12, and 10%,
respectively, compared with 85% in the control group. These results indicate that the aqueous extract of C. formosum may elevate the innate immune response and enhance disease resistance in tilapia. 相似文献
6.
The present study was carried out to determine the antibacterial effect of caprylic acid in the culture system of Artemia franciscana nauplii inoculated with shrimp pathogens Vibrio harveyi and V. parahaemolyticus. To begin with, the antibacterial effect of different concentrations (1, 10 and 100 mM) of caprylic acid against V. harveyi and V. parahaemolyticus was assessed through bacterial growth study. This indicated that at 100 mM concentration, the growth of the pathogens was
completely inhibited within 5 h, whereas, in 1.0 and 10 mM concentrations, effective inhibition was observed with the extension
of time. Subsequently, the influence of pH variation on the growth inhibitory effect of 10 mM caprylic acid against V. harveyi and V. parahaemolyticus at different pH (5–7) was also made through bacterial growth study. At pH 5, the pathogen growth was very less, compared
with pH 6 and 7. The Artemia nauplii (instar II) reared in 10 mM caprylic acid supplemented medium were challenged with V. harveyi and V. parahaemolyticus, and the mortality was recorded at an interval of 6 h up to 60 h. In this study, the mortality of Artemia nauplii reduced to 20.61 and 16.30% in V. parahaemolyticus and V. harveyi challenged groups, respectively. The present results provide evidence for the potential antibacterial activity of caprylic
acid in aquaculture against luminescent vibrios. 相似文献
7.
Jian-He Xu Feng You Wei Sun Bin-Lun Yan Pei-Jun Zhang Bi-Xiang Jing 《Aquaculture International》2008,16(6):623-634
Turbot Scophthalmus maximus exhibits sexually dimorphic growth, with females growing faster and reaching larger adult sizes than males. Thus, development
of techniques for preferentially producing females is necessary to optimize production of these species. In this paper, gynogenetic
diploids of turbot were induced by activating egg development with ultraviolet (UV)-irradiated left-eyed flounder Paralichthys olivaceus sperm combined with cold shock to prevent extrusion of the second polar body. The results of UV irradiation experiments showed
that survival, motility, and duration of activity of P. olivaceus sperm generally decreased with increase in UV dose. The typical Hertwig’s effect was observed after fertilized turbot eggs
with UV-irradiated P. olivaceus sperm and the optimal UV dose for gynogenetic haploid production was 36,000 erg mm−2. At 15°C, appropriate timing of cold shock for retention of the second polar body in turbot eggs was at 6 min after fertilization.
Results of different combinations of two shock temperatures (1 or 3°C) and four shock durations (15, 25, 35 or 45 min) at
6 min after fertilization demonstrated that shock of 25 min at 1°C gave the highest production of diploid gynogens (39.58%
relative to its diploid control). The results of this study reveal that the use of UV-irradiated P. olivaceus sperm for activation of turbot eggs and cold shock for polar body retention is an effective method to produce gynogenetic
offspring. 相似文献
8.
Shuang Jiao Zhihao Wu Xungang Tan Yulei Sui Lijuan Wang Feng You 《Fish physiology and biochemistry》2017,43(2):385-395
Although chromosome set manipulation techniques including polyploidy induction and gynogentic induction in flatfish are becoming increasingly mature, there exists a poor understanding of their effects on embryonic development. PAX3 plays crucial roles during embryonic myogenesis and neurogenesis. In olive flounder (Paralichthys olivaceus), there are two duplicated pax3 genes (pax3a, pax3b), and both of them are expressed in the brain and muscle regions with some subtle regional differences. We utilized pax3a and pax3b as indicators to preliminarily investigate whether chromosome set manipulation affects embryonic neurogenesis and myogenesis using whole-mount in situ hybridization. In the polyploid induction groups, 94 % of embryos in the triploid induction group had normal pax3a/3b expression patterns; however, 45 % of embryos in the tetraploid induction group showed abnormal pax3a/3b expression patterns from the tailbud formation stage to the hatching stage. Therefore, the artificial induction of triploidy and tetraploidy had a small or a moderate effect on flounder embryonic myogenesis and neurogenesis, respectively. In the gynogenetic induction groups, 87 % of embryos in the meiogynogenetic diploid induction group showed normal pax3a/3b expression patterns. However, almost 100 % of embryos in the gynogenetic haploid induction group and 63 % of embryos in the mitogynogenetic diploid induction group showed abnormal pax3a/3b expression patterns. Therefore, the induction of gynogenetic haploidy and mitogynogenetic diploidy had large effects on flounder embryonic myogenesis and neurogenesis. In conclusion, the differential expression of pax3a and pax3b may provide new insights for consideration of fish chromosome set manipulation. 相似文献
9.
There is a need to develop low-cost methods for larviculture that emphasize disease prevention. We evaluated stagnant water
larviculture in flounder Paralichthys olivaceus using rotifer amictic eggs treated with glutaraldehyde. Growth and survival of the larvae were similar to in larvae reared
by standard running water larviculture with daily feeding of rotifers (control). In the experimental group, the n-3 highly
unsaturated fatty acid content of rotifers in the rearing water was higher than in the enriched rotifers fed to the control
group. We also observed a similar pattern for the fatty acid composition of flounder larvae. The viable bacterial counts associated
with rotifers in stagnant water were lower than those associated with enriched rotifers, and there were fewer bacterial genera.
However, the viable bacterial count was the same or higher in the experimental rearing water compared with that in the control
group. The α-Proteobacteria and Cytophaga–Flavobacterium–Bacteroidetes group dominated the bacterial community structure after larval hatching. To our knowledge, this is the first time that stagnant
water larviculture, using only disinfected amictic eggs, has been successfully demonstrated on a mass production scale. This
method appears to offer benefits including improved nutrition, more favorable bacterial communities, and lower cost. 相似文献
10.
Mortality of the short-neck clam Ruditapes philippinarum exposed to the toxic dinoflagellate Heterocapsa circularisquama was studied under controlled conditions to clarify the mechanisms of recurrent mass deaths of clams occurring in western
Japanese coastal areas. One-week mortality tests, involving three water temperatures, six H. circularisquama concentrations, and two clam body sizes, showed a significant increase in mortality with increasing temperature, H. circularisquama concentration, exposure duration, and body size (ANOVA, P < 0.01). Clam death was observed at concentrations as low as 50 cells/ml and temperatures as low as 15°C. Prior to death,
clams showed an extreme retraction of their mantle edge and siphon, along with recurrent vomiting behavior before initiating
a closure reaction followed by paralysis then death. Gills of paralyzed clams showed an important uptake of dye, implying
gill damage. This study is the first laboratory evidence of bivalve mortality induced by H. circularisquama at low concentrations and low temperature, and the first report of differential effects according to the body size of bivalves. 相似文献
11.
Pseudotuberculosis is a bacterial septicaemia caused by Photobacterium damselae subsp. piscicida in several marine fish species. Yellowtail Seriola quinqueradiata is the most sensitive fish species to this disease. The internal organs of naturally infected yellowtail exhibit whitish
spots, tubercle-like tissue structures, consisting of bacterial accumulations. There have been many trials for experimental
infection, however adequate method of infection that reproduces moderate mortality and primary clinical signs has not yet
established. Present investigation evaluated an immersion infection method by using logarithmic culture-phase bacteria resulting
in higher mortality than that using stationary culture-phase bacteria. Typical white spots on the spleen and kidney were also
observed constantly in dead fish. Transmission electron microscopy and fluorescent antibody microscopy showed bacterial clusters
not only in the spleen and kidney but also in the blood channels in the secondary gill filaments. These results were confirmed
repeatedly by plural experiments. The use of logarithmic-phase bacteria in immersion infection is an appropriate technique
to reproduce moderate mortality and primary clinical signs, which will be a reliable infection method also for the challenge
test of pseudotuberculosis vaccine. 相似文献
12.
In August 2008, a massive epizootic occurred among Portunus trituberculatus reared together with Palaemon carincauda Holthuis and Sinonovacula constricta in the seawater pond of Ningang farm, Rudong district, Jiangsu province, China. The disease occurred in crabs from juveniles
to adults, and the mortality rate reached 30–40%. The diseased crabs exhibited lethargy, hepatopancreas turgidity, and elevated
levels of turbid hemolymph. A gram-negative, rod-shaped bacterium (designated as strain LGS-1) was isolated from the ascitic
fluid of the diseased and moribund crabs and was confirmed as the causative agent by our infectivity study. We conducted morphological
and biochemical characterization of LGS-1, and sequenced the 16S rRNA gene, which led us to identify the bacterium as Vibrio metschnikovii. Drug sensitivity tests showed that this pathogenic bacterium is sensitive to florfenicol, orfloxacin, and SXT, but completely
resistant to antibacterial drugs like gentamicin, erythrocin, and acheomycin. This is the first report on Vibrio metschnikovii as a virulent pathogen for Portunus trituberculatus. 相似文献
13.
Streptococcus dysgalactiae strains have been isolated from cultured amberjack Seriola dumerili and yellowtail Seriola quinqueradiata in Japan. To characterize the fish isolates, we performed genetic analysis and compared the biochemical properties of these
isolates with those of the S. dysgalactiae subsp. dysgalactiae and S. dysgalactiae subsp. equisimilis strains isolated from mammals. The genetic analysis revealed that the fish isolates were genetically very similar to each
other with high DNA–DNA relatedness (>95.4%) and sequence homology. Meanwhile, the DNA relatedness between mammalian isolates
and the fish isolates was 73.4–82.6%. In biased sinusoidal gel electrophoresis (BSFGE) analysis, the restriction patterns
of mammalian isolates were different from those of fish isolates. The fish isolates did not show streptokinase activity in
plasminogen obtained from mammals. These characteristics enabled us to distinguish between the fish isolates and the Sdd and Sde strains isolated from mammals. In order to obtain epidemiological information on the fish isolates, BSFGE patterns from 284
S. dysgalactiae strains from fish in Japan were examined. Based on the results of BSFGE analysis, the fish isolates were classified into
16 groups (AP1–AP16) with restriction enzyme ApaI. The dendrogram based on BSFGE analysis indicated that all fish isolates using in this study were closely related. 相似文献
14.
Ofelia S. Reyes Marietta N. Duray Corazon B. Santiago Manuele Ricci 《Aquaculture International》2011,19(1):155-164
The free-living nematode, Panagrellus redivivus, was tested as live food for grouper Epinephelus coioides larvae during the first feeding stage. A series of experiments were conducted to determine the acceptability of the free-living
nematodes in grouper larvae at first feeding, the optimum nematode density and the response of the larvae to nutritionally
enriched nematode. All experiments were conducted in 200-L conical tanks filled with 150-L filtered seawater and stocked at
15 larvae L−1. Duration of feeding experiments was up to day 21 (experiment 1) and 14 days (experiment 2 and 3). Brachionus plicatilis and Artemia (experiment 1) and Brachionus plicatilis alone (experiment 2 & 3) was used as the control treatment. Observations indicated that the grouper larvae readily fed on
free-living nematodes as early as 3 days posthatching, the start of exogenous feeding. Optimum feeding density for the larvae
was 75 nematodes ml−1. The enrichment of cod liver oil or sunflower oil influenced the total lipids and n-3 highly unsaturated fatty acids of P. redivivus, which in turn influenced those of the grouper larvae, however, growth and survival of the larvae were not affected (P > 0.05). The results from this investigation showed that the nematode, P. redivivus, can be used as first live food for grouper larvae from the onset of exogenous feeding until they could feed on Artemia nauplii. 相似文献
15.
16.
Thomas H. Galley Frederico M. Batista Richard Braithwaite Jon King Andy R. Beaumont 《Aquaculture International》2010,18(3):315-325
The blue mussel Mytilus
edulis is a commercially important species whose fishery and culture generally relies on natural spat collection. Hatchery-production
could provide an alternative source of seed, enabling reliable expansion of the industry. Mussel spawning and larval rearing
trials were carried out to optimise elements of hatchery production. Culturing fertilised eggs at low density (20–200 eggs cm−2) rather than high density (400–720 eggs cm−2) significantly improved the quality of first veliger larvae and differences in this improvement were evident between the
eggs from different females (maternal effects). Veliger larval growth at 17 or 21°C was significantly faster than growth at
14°C. Feeding veliger larvae an identical total ration either daily or at 2–3 day intervals did not significantly affect their
growth. Different microalgal diets (1: Isochrysis sp. (clone T-ISO), 2: Chaetoceros
calcitrans forma pumilus, 3: C. muelleri, 4: mixed Isochrysis sp. (clone T-ISO) and C. calcitrans f. pumilus, and 5: mixed Isochrysis sp. (clone T-ISO) and C. muelleri) were tested on veliger larval growth and mixed diets outperformed single-species diets. 相似文献
17.
The immediate-early gene (egr-1) expression was used to examine the neuron’s response in telencephalon of goldfish during spatial learning in small space.
Fishes were pre-exposed in the experimental apparatus and trained to pick food from the tray in a rectangular-shaped arena.
The apparatus was divided into identical compartments comprising three gates to provide different spatial tasks. After the
fish learned to pass through the gate one, two more gates were introduced one by one. Fish made more number of attempts and
took longer time (P < 0.05) to pass through the first gate than the gate two or three. This active learning induces the expression of egr-1 in telencephalon as established by western blot analysis. Subsequently, the fish learn quickly to cross the similar type
of second and third gate and make fewer errors with a corresponding decline in the level of egr-1 expression. As the fish learned to pass through all the three gates, third gate was replaced by modified gate three. Interestingly,
the level of egr-1 expression increased again, when the fish exhibit a high exploratory behavior to cross the modified gate three. The present
study shows that egr-1 expression is induced in the telencephalon of goldfish while intensively acquiring geometric spatial information to pass
through the gates. 相似文献
18.
Qing-Kui Wang Cheng-Xun Chen Yong-Jun Guo Hai-Yun Zhao Jing-Feng Sun Shen Ma Ke-Zhi Xing 《Aquaculture International》2011,19(5):945-956
The purpose of this study was to determine the effect of Angelica sinensis polysaccharide (ASP) supplemented in diet on the innate cellular immune response and disease resistance in grouper, Epinephelus malabaricus. Fish were fed diets containing different doses of ASP (0, 500 and 3,000 mg kg−1 diet) for 12 weeks. After 12 week feeding, the respiratory burst activity, phagocytic activity, and leukocytes proliferation
in head kidney were assayed. The functional immunity in terms of cumulative mortality was also assessed by a challenge with
live Edwardsiella tarda. Results showed that the respiratory burst activities in ASP-supplemented groups were increased significantly. The respiratory
burst index was the highest in fish-fed 3000 mg kg−1 diet and the lowest in control. The phagocytic activities in ASP-supplemented groups were significantly higher than that
of control. No significant difference in phagocytic activity was observed between ASP-supplemented groups. ASP stimulated
the head kidney leukocytes proliferation significantly, despite the absence of lipopolysaccharide (LPS) or not. The cumulative
mortalities of fish fed with 3000 mg ASP kg−1 diet were significantly lower than those fed with 500 mg ASP kg−1 diet and control diet after 96 h of challenge. In conclusion, dietary ASP enhanced some cellular immune parameters and disease
resistance against E. tarda in grouper. 相似文献
19.
Suchanit Ngamkala Kunihiko Futami Masato Endo Masashi Maita Takayuki Katagiri 《Fisheries Science》2010,76(5):833-840
The present study histologically examined the effects of glucan-containing and Lactobacillus rhamnosus GG (LGG)-containing diets on intestinal damages inflicted on Nile tilapia by Aeromonas challenges. Tilapia were fed control, glucan, and LGG diets for 2 weeks and were subsequently challenged with Aeromonas. The intestines were then histologically examined at 1, 7, 14, and 21 days post-infection. Mortality following the challenge
was lower for the fish fed the glucan and LGG diets. The intestines of these groups also showed increased inflammatory cell
infiltration and reduced intestinal damage from Aeromonas. Moreover, inflammatory cell infiltration occurred more rapidly in the glucan-fed than in the LGG-fed fish following the
challenge. Before the challenge, the dominant mucous cell was the acid type in all the tests. After the challenge, the main
mucus cell type in the proximal intestine of the glucan-fed fish shifted to AB-PAS double-staining cells, while in the LGG-fed
fish, it remained the acid type throughout the test period, and the number of double-staining cells was smaller than in the
control fish after the challenge. Thus, the different mucous cell and inflammatory cell responses show that glucan and LGG
might have different immunostimulative effects, although they both reduced the intestinal damage following Aeromonas challenges. 相似文献
20.
Shahram Shakiba Zadeh Che Roos Saad Annie Christianus Mohd Salleh Kamarudin Kamaruzaman Sijam Mariana Nor Shamsudin Vasantha Kumari Neela 《Aquaculture International》2010,18(6):1017-1026
To conquer disease problem in shrimp industries, probiotic biocontrol is a well-known remedy now. The antagonistic ability
of separated isolates from different parts of juvenile P. monodon was screened against shrimp Vibrio pathogens, V. parahaemolyticus and V. alginolyticus. The most antagonistic effect was observed for an isolate that primarily identified as Shewanella algae using conventional method followed by Biolog GN and GP microplates. Since adaptability to the host optimum cultural condition
of the target organism is of the great importance, response surface methodology, with central composite design, was applied
to assess log cell count response of S. algae in different incubation conditions. Therefore, four independent variables were assumed as: temperature (10–50°C), pH (6–10),
NaCl concentration (0–50‰) and time (12–60 h). The coefficients of multiple determinations (R
2) for the responses log cell count of S. algae being 0.827. Temperature was the merely significant independent variable that affected the log cell count of the candidate
probiotic. The candidate probiotic was revealed a reasonable growth response in quite wide range of temperature, pH and NaCl
concentration in which the maximum levels were in same range of optimum shrimp culture. 相似文献