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1.
Haematological and serum biochemistry parameters were studied and compared between cultured and wild ecotypes of Dojo loach
Misgurnus anguillicaudatus during the prime fishing season, i.e. May–August. Data were analysed for the impact of feeding regime and other ecological
conditions on the physiology of fish. The results revealed that haemoglobin, cholesterol, total protein, creatinine and uric
acid levels in the two ecotypes were significantly different (n = 56, df = 54, P < 0.05). In addition, red blood cell, glucose, triglyceride and urea nitrogen levels were significantly higher in cultured
individuals (n = 56, df = 54, P < 0.01) than in their wild counterparts. In contrast, the white blood cell level in cultured fish was significantly (n = 56, df = 54, P < 0.01) lower than that in the wild ones. These differences can be attributed to the physiological acclimatization of the
fish to their living conditions and feeding regime, which influences the energy metabolism and, consequently, the health of
the fish. 相似文献
2.
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
3.
Youji Wang Menghong Hu Weimin Wang S. G. Cheung P. K. S. Shin Ling Cao 《Aquaculture International》2010,18(2):135-148
The effects of delayed first feeding on growth and survival and starvation on the point-of-no-return of loach Misgurnus anguillicaudatus larvae were studied by evaluating morphometric characteristics under controlled conditions. Larvae began to feed exogenously
at 3 days after hatching (DAH) and the PNR occurred between 9 and 10 DAH at 23 ± 1.0°C. The experimental design included a
conventional feeding regime with initial feeding from 3 DAH as a control, delayed first feeding for 4, 5 and 6 DAH. Morphometric
characteristics (head depth, body depth, eye diameter, mouth diameter, musculature height, total length and yolk sac volume)
were evaluated under different initial feeding time (3, 4, 5 and 6 days after hatching). Loach larvae initiated first feeding
at 4, 5 and 6 days after hatching achieved comparatively lesser growth performance in all morphometric characteristics than
that of 3 days at the end of the experiment. By day 6, significant differences were observed between 3 and 6 days initial
feeding larvae for all morphometric characteristics except eye diameter and mouth diameter. Similarly, significant differences
were noticed between 3 and 5 days initial feeding. However, there were no significant differences in head depth, body depth,
eye diameter, mouth diameter, and total length between 3 and 4 days initial feeding until 12 DAH. After 15 days rearing, significant
differences in all morphometric characteristics appeared between 3 and 4 days initial feeding and followed to the end of the
experiment. It was also observed that the yolk absorption in loach larvae was completed by 6 days irrespective of the differences
in the initial feeding. The yolk volume of 4 and 5 DAH larvae initiated first feeding at 3 days (0.0125 ± 0.0015; 0.0077 ± 0.0009 mm3) had significant differences compared with yolk volume of larvae initiated first feeding at 4 days (0.0081 ± 0.0011; 0.0039 ± 0.0004 mm3), 5 days (0.0079 ± 0.0010; 0.0017 ± 0.0002 mm3) and 6 days (0.0082 ± 0.0011; 0.0016 ± 0.0001 mm3). Survival rates of four treatments were estimated daily for 30 days and significant differences were observed between the
treatments at the end of the experiment. The final survival rate was higher when the loach larvae initiated feeding at 3 days
(75.9%) when compared with 4 days (31.8%), 5 days (14.5%) and 6 days (6.4%). The present study suggests that the first feeding
of loach larvae should be initiated at 3 DAH for achieving better growth and survival or else bad growth performance will
engender if the first feeding is delayed. 相似文献
4.
Ioannis E. Papadakis Stavros Chatzifotis Pascal Divanach Maroudio Kentouri 《Aquaculture International》2008,16(1):13-25
The weaning of greater amberjack (Seriola dumerilii Risso 1810) to a dry diet was studied in two consecutive experiments. The experimental fish were hatchery-produced and grown
to their initial size on a soft pellet containing 50% trash fish and 50% commercial dry pellet. In the first experiment, three
homogenous groups of greater amberjacks (n = 153, mean weight: 374 ± 43 g), initially adapted for a period of 30 days to a diet with a 40% moisture content, were fed
on commercial pellets containing three different levels of dietary moisture (7, 20 and 40%, respectively) for 126 days. We
found that fish needed a month to adapt to the 7%- and 20%-moisture diets and that moisture content of the diet had a significant
effect on fish growth in terms of increasing feed consumption and lowering feed conversion ratio. The group fed on the 20%-moisture
diet not only compensated for the initial adaptation period but presented the higher growth rate and best feed conversion
ratio. In the second experiment, all groups of experiment 1 were fed the same commercial diet with a 7% moisture content for
72 days. The group that had been previously fed on the 20%-moisture diet showed the best growth performance. The implication
of the above results for the weaning of greater amberjack to dry diets is discussed in terms of the digestion process and
physiology. 相似文献
5.
To find out whether or not the locomotor activity of the Japanese sea catfish, Plotosus lineatus, shows a circadian rhythmicity, the locomotor activity of this catfish was recorded in a laboratory. All of the catfish recorded
(n = 20) showed a nocturnal locomotor activity rhythm under a light–dark (LD) cycle (LD 12:12). The locomotor activity started
after the light was turned off, and declined during the period of darkness. In five of the six catfish we examined, locomotor
activity shifted gradually over the course of 3–4 days in order to synchronize to the LD cycle after it was advanced by 6 h.
Locomotor activity persisted within a constant darkness (DD) in all eight of the catfish. The average free-running period
of locomotor activity under DD lasted for 24.2 ± 0.4 h (mean ± SD). Thus, the present results demonstrate that the Japanese
sea catfish has an endogenous circadian oscillator entrained by an LD cycle. 相似文献
6.
7.
8.
Melatonin production by the fish pineal is under the control of photoperiod. In addition, in some fish species pineal melatonin production is self-sustained by an intrapineal circadian pacemaker, not in salmonids, though. The aim of this research was to test melatonin release in vitro by the pineal of sea bass held under LD 12:12 and DD conditions to determine the endogenous nature of melatonin rhythm. Circadian rhythmicity ( = 28.3 h) was found since rhythmic melatonin release persisted on DD. 相似文献
9.
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
10.
The effects of soy sauce koji and the lactic acid bacterium, Tetragenococcus halophilus, were studied on the fermentation of fish sauce prepared from Chinese silver carp. The fish sauce prepared without koji and the lactic acid bacterium contained low levels of organic materials, total nitrogen, and organic acids. The use of koji was effective in increasing these qualitative parameters and further improved the amino acid score of the fish sauce. Addition
of T. halophilus had an effect on lowering the pH value during the initial period of fermentation when the soy sauce koji was also supplemented. In contrast, T. halophilus-like bacteria were found to be predominant for all tanks fermented under the different starting conditions. Although it was
not examined whether the T. halophilus-like bacteria observed after fermentation were the same as the starter-bacterium or not, it was suggested that T. halophilus plays an important role in the successful fermentation of silver carp fish sauce. Sensory evaluation conducted with Japanese
and Chinese panelists also suggested the superiority of the use of koji for fermentation of silver carp fish sauce. 相似文献
11.
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
12.
J. D. Celada J. M. Carral R. Rodríguez M. Sáez-Royuela A. Aguilera P. Melendre J. Martín 《Aquaculture International》2007,15(6):489-495
After artificial reproduction of tench, larvae must be maintained indoors, and studies on rearing conditions are needed, focussing
on the reduction of labour and costs. Three experiments on larvae (5th day post-hatch) were conducted for 25 days using Artemia nauplii as the sole food in order to determine basic feeding and density conditions during the first rearing period. Tench
were maintained in 25 l fibreglass tanks, supplied with an artesian water flow throughout of 0.2 l min−1. Water temperature was 22.5 ± 1°C, and the photoperiod was natural. Larvae fed on a restricted amount of nauplii reached
high survival rates, even with the minimum of 50 nauplii larva−1 day−1. This amount of food may be sufficient at least for the first 25 days of exogenous feeding if fast growth is not the priority,
and high densities can be maintained with good survival rates (over 90% up to 160 larvae l−1 and 77% with 320 larvae l−1). When food was supplied in excess once a day, high survival rates were achieved (91–97%), without differences among the
densities tested. Animals at a density of 100 l−1 reached the highest length (15.57 mm) and individual weight (46.8 mg). This growth is greater than those reported in studies
feeding several times a day. It could be deduced that, while live food remains available for tench, it is not necessary to
feed so frequently. Considering the relationship among the initial number of animals, final survival and growth and ration
supplied, the new data reported here are useful to establish suitable stocking densities under both culture and experimental
conditions. 相似文献
13.
Xiaoyun Zhou Khalid Abbas Mingyun Li Libao Fang Su Li Weimin Wang 《Aquaculture International》2010,18(3):349-359
To determine the cytotype with better traits for the aquaculture practices of the dojo loach Misgurnus anguillicaudatus from the viewpoint of fish farming improvement, factorial crosses (2n♀ × 2n♂, 2n♀ × 4n♂, 4n♀ × 2n♂, 4n♀ × 4n♂) were conducted
between natural diploids (D) and tetraploids (T), producing DD, DT, TD, and TT groups (female listed first). The potential
benefits of the different cytotypes in culture were evaluated by comparing growth performance and survival rate for a 15-month
rearing trial under the same production conditions. The average fertilization rate in DT and TT was significantly lower than
in the DD and TD groups, possibly indicating the poor fertilizing capacity of the tetraploid sires. Survival rate in DT and
TD was slightly lower than in DD but significantly higher than in the TT groups. Tetraploid females produced obviously larger
eggs than diploids and, subsequently, significantly longer initial body length of TT and TD than DD and DT fry. However, from
the second month of the growth trial, TT suffered higher mortality than other cytotypes, which significantly influenced morphometric
growth parameters. The TD group exhibited superior growth performance throughout the experiment. The mean body length of DT
was comparable with that of DD fish during the first 7 months but began to outgrow DD from the 9th month. This study suggests
that the relatively better growth of tetraploid and higher survival rate of diploid can be integrated via inter-ploidy hybridization
to get TD triploids with better culture traits. 相似文献
14.
Alvarez-González CA Moyano-López FJ Civera-Cerecedo R Carrasco-Chávez V Ortiz-Galindo JL Dumas S 《Fish physiology and biochemistry》2008,34(4):373-384
Spotted sand bass Paralabrax maculatofasciatus is a potential aquaculture species in Northwest Mexico. In the last few years it has been possible to close its life cycle
and to develop larviculture technology at on pilot scale using live food, however survival values are low (11%) and improvements
in growth and survival requires the study of the morpho-physiological development during the initial ontogeny. In this research
digestive activity of several enzymes were evaluated in larvae, from hatching to 30 days after hatching (dah), and in live
prey (rotifers and Artemia), by use of biochemical and electrophoretic techniques. This paper, is the first of two parts, and covers only the biochemical
analysis. All digestive enzyme activities were detected from mouth opening; however the, maximum activities varied among different
digestive enzymes. For alkaline protease and trypsin the maximum activities were detected from 12 to 18 dah. Acid protease
activity was observed from day 12 onwards. The other digestive enzymes appear between days 4 and 18 after hatching, with marked
fluctuations. These activities indicate the beginning of the juvenile stage and the maturation of the digestive system, in
agreement with changes that occur during morpho-physiological development and food changes from rotifers to Artemia. All enzymatic activities were detected in rotifers and Artemia, and their contribution to enhancement the digestion capacity of the larvae appears to be low, but cannot be minimised. We
concluded that the enzymatic equipment of P. maculatofasciatus larvae is similar to that of other marine fish species, that it becomes complete between days 12 and 18 after hatching, and
that it is totally efficient up to 25 dah. 相似文献
15.
16.
Leon T. N. Heinsbroek Bart J. Goedegebuur Gertrude Bloemhof Robert B. Flach Gert D. C. de Jong 《Aquaculture International》2008,16(2):93-108
Gastrointestinal and metabolic influences on short- and medium-term control of voluntary feed intake of European eel were
investigated for groups of fish fed at different feeding schedules: 1 meal 2 days−1, 1 meal day−1, 2 meals day−1 and continuous feeding for 12 h and 24 h daily. For fish fed daily, the feeding schedule had no effect on feed intake, metabolism,
growth, size variation and body composition. Only fish fed once every 2 days could not completely compensate by increasing
their average meal size and showed a reduced feed intake, metabolism and growth. Stomach capacity did not limit meal size
and feed intake as large differences in appetite were found for eels with empty stomachs. Feed intake was related to metabolism
as the levels of O2 consumption and NH4 excretion just before the meal were correlated to average meal size, suggesting that rate (and duration) of metabolism is
sensed and is providing information about the metabolic consequences of feed intake and feed processing. Meal size is based
on the (expected) scope for metabolism and eels seem to strive to an average daily feed intake, associated with their developmental
state (growth potential). Plasticity in this feed intake behaviour, expressed by individual variation in feed intake and day-to-day
fluctuations in individual and group intake, is regarded as adaptive on different time scales. 相似文献
17.
Keita Kodama Masaaki Oyama Jeong-Hoon Lee Yoshiaki Akaba Yoshihiro Tajima Takamichi Shimizu Hiroaki Shiraishi Toshihiro Horiguchi 《Fisheries Science》2009,75(4):875-886
To explore which lifestages affect the stock size of young-of-the-year mantis shrimp Oratosquilla oratoria in Tokyo Bay, Japan, we investigated interannual variations in the quantitative relationships among egg production, larval
density, and juvenile density. We collected adult females, larvae, and juveniles during monthly field surveys from 2004 to
2007. The interannual trend for the juvenile density index differed from those for egg production and larval density; although
indices of both egg production and larval density were high in 2004 and 2007, the juvenile density index was high only in
2007, suggesting high mortality during the pelagic larval stage or the early phase of the postsettlement juvenile stage in
2004. We found that larval settlement started at the end of August and peaked in October, although larvae from the early spawning
season (May–June) should have settled in August or earlier. Juveniles were found throughout the bay except in areas where
bottom hypoxia occurred, suggesting that hypoxia restricts the spatial distribution of juveniles. Our results suggest that
mortality during the early life history fluctuates among years, probably because of changes in environmental conditions in
the bay, resulting in interannual variation in the stock size of young-of-the-year juvenile O. oratoria. 相似文献
18.
An eight-week experiment was carried out to evaluate the effects of different protein sources (fish and haemoglobin meal, soybean meal and torula yeast), in practical diets, on growth, body composition and gut morphology of fingerling grey mullet (Mugil cephalus). Weight gain (%), SGR, FCR, N retention, PER, PGR, FDR and carcass composition of fish were not significantly affected by the dietary protein source. Fish fed the torula yeast based diet showed reduction in growth performance. Histological examinations performed on the alimentary tract of the fish showed a normal structural pattern in the experimental groups, as fundamental histological and histochemical aspects were similar if compared to the control group. The lower growth performance observed in fish fed a torula yeast based diet may be tentatively correlated with the presence of some detrimental morpho-functional aspects in the gut of these fish if compared to fish fed the other diets. Further studies are necessary to confirm this hypothesis. 相似文献
19.
20.
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