共查询到20条相似文献,搜索用时 15 毫秒
1.
Jesus D. Celada Amelia Aguilera Jose M. Carral María Sáez-Royuela Pedro M. Melendre Jose R. Pérez 《Aquaculture International》2007,15(6):461-465
In two 120-day experiments, performed in the laboratory at 22°C, the effects of stocking density on the survival and growth
of juvenile tench (Tinca tinca L.) were evaluated. Fish were kept in fibreglass tanks, supplied throughout with flow of artesian water, and fed a dry diet
for salmonids, in excess, supplemented with restricted amounts of Artemia nauplii. In the first experiment four-month-old juveniles (0.31 ± 0.04 g and 32.00 ± 1.17 mm TL) were stocked at four densities—0.18,
0.88, 1.05, and 2.10 g l−1. Survival was high (>89%) for all treatments. Final densities ranged between 1.10 g l−1 (significantly lowest) and 10.46 g l−1 (significantly highest). The density increase was significantly higher (611%) for fish stocked at the lowest initial density
(0.18 g l−1) than for fish stocked at 0.88, 1.05, and 2.10 g l−1, for which the density increase averaged 457%. In the second experiment, 4.5-month-old juveniles (0.58 ± 0.17 g and 39.54 ± 0.83 mm
TL) were stocked at three densities—1.05, 3.00, and 4.00 g l−1. Survival was high (>96%) for all treatments. Final densities ranged between 4.08 and 16.53 g l−1 and were significantly higher for greater initial densities. The density increase was greatest (413%) for fish stocked at
the highest density (4 g l−1) and was not significantly different for fish stocked at 1.05 and 3 g l−1. Considering all the densities in the two experiments, for stocking at 4 g l−1 the final density was 15 times higher than that reached after stocking at 0.18 g l−1, without harmful effects on survival and growth. This final density (equivalent to 16.53 kg m−3) is in the range recommended for other fish species in this period under intensive conditions. 相似文献
2.
Huayu Song Mengxun Wang Zhongkai Wang Haiyang Yu Zhigang Wang Quanqi Zhang 《Fish physiology and biochemistry》2016,42(4):1073-1092
3.
Takayuki Kobayashi Toshiya Nagase Akinori Hino Toshio Takeuchi 《Fisheries Science》2008,74(3):649-656
ABSTRACT: A continuous culture of rotifer was conducted to investigate the effect of combination feeding of both a high density of Nannochloropsis oculata (N) and condensed freshwater Chlorella (FC) on the fatty acid composition of L-type rotifer Brachionus plicatilis in a continuous culture system. The algal feeding of the rotifers was carried out in three successive steps: N-feeding → N+FC-feeding → FC-feeding. The culture was conducted at 24°C and 25–27 psu in a 2000 mL bottle with 50% of water exchanged daily. The combination N+FC-feeding was effective in increasing rotifer density. The rotifers fed on N+FC (N+FC-R) had more non-polar lipids than polar ones, similar to those on N (N-R), opposite to the rotifers fed on FC (FC-R). N+FC-R contained higher levels of 16:2, 18:2n-6 (linoleic acid [LA]) and 20:2n-6, but lower levels of 18:1, 20:4n-6 (arachidonic acid), 20:5n-3 (eicosapentaenoic acid [EPA]) and 22:5n-3 (docosapentaenoic acid [DPA]) compared with N-R. Whereas N+FC-R contained higher levels of 16:1n-7, EPA and DPA, but lower levels of 16:2 and LA compared with FC-R. N+FC-R had more DPA in polar lipids than in non-polar ones. The Σn-6/Σn-3 ratio in N+FC-R was 0.9–1.0, significantly different from those in N-R (0.4) and FC-R (6.6–8.4). Therefore, it is inferred that the fatty acid profile of the N+FC-R cultured in a continuous culture system was affected by both N and FC. Also, the combination N+FC-feeding may be effective in manipulating the Σn-6/Σn-3 ratio in continuously cultured rotifers. 相似文献
4.
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
5.
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
6.
Toshihiro Onitsuka Tomohiko Kawamura Shunsuke Iwanaga Satoshi Ohashi Toyomitsu Horii 《Fisheries Science》2010,76(4):619-623
The dietary value of juvenile stages (gametophyte and juvenile sporophyte) of the brown macroalga Eisenia bicyclis for post-larval and juvenile abalone Haliotis diversicolor of 2.0–6.5 mm in shell length (SL) was examined and compared with that of a benthic diatom, Nitzschia sp., in laboratory experiments. Most abalone actively fed on these diets, but there were large variations in the growth rate
among the diets and among the growth stages of abalone. Growth rates of abalone fed on Nitzschia sp. were highly variable within each growth stage, but showed no clear differences among growth stages. In contrast, in abalone
fed gametophytes or juvenile sporophytes, growth rates linearly increased as abalone grew. Growth rates of >60 μm SL/day were
observed in juveniles of >3 mm SL fed gametophytes, and juveniles of >5 mm SL fed juvenile sporophytes. These results indicate
that the dietary value of the juvenile stages of E. bicyclis for the abalone changes as they grow, and with growth juvenile abalone begin to efficiently utilize gametophytes and juvenile
sporophytes in that order. 相似文献
7.
Huayu Song Mengxun Wang Zhongkai Wang Jinxiang Liu Jie Qi Quanqi Zhang 《Fish physiology and biochemistry》2017,43(3):731-753
Reproduction allows organisms to produce offspring. Animals shift from immature juveniles into mature adults and become capable of sexual reproduction during puberty, which culminates in the first spermiation and sperm hydration or ovulation. Reproduction is closely related to the precise control of the hypothalamic–pituitary–gonadal (HPG) axis. Kisspeptin peptides are considered as the important regulator of HPG axis in mammalian. However, the current understanding of kisspeptin in flatfish is not comprehensive. In this study, we cloned and analyzed the kiss2 and kissr2 genes in Cynoglossus semilaevis. Interesting alternative splicing in the 5′-untranslated regions (UTR) of the Cskissr2 gene was found. The expression profiles of Cskiss2 and Cskissr2 showed relative high messenger RNA (mRNA) levels at the late gastrula stage during embryonic development, at total length = 40 mm during early gonadal differentiation, and in the brains and gonads of all investigated tissues. These results suggested that the kisspeptin system participated in embryogenesis and in the regulation of gonadal differentiation and development. Considering that the control and regulatory mechanisms of kisspeptin in the central reproductive axis are still unclear, we documented that the intramuscular injection of kisspeptin caused different sGnRH and cGnRH mRNA levels in a dose- and tissue-dependent manner. The mRNA expressions of FSH and LH were stimulated in the ovary and were inhibited in the testis under the kisspeptin treatments. These results provided foundations for understanding the roles of kisspeptin in the neuroendocrine system in fish. The manipulation of the kisspeptin system may provide new opportunities to control the gonadal development and even reproduction in fish. 相似文献
8.
Kazutoshi Okamoto 《Fisheries Science》2008,74(1):98-103
ABSTRACT: Larvae of the Japanese nephropid lobster Metanephrops japonicus hatched in the laboratory were reared at 15°C, and the development and feeding were observed. All larvae hatched at the 'prezoea stage' with no natatory setae on the exopodite of the pereiopods. Without feeding, 50% of prezoea molted into the megalopa stage, having small buds as the exopodite, within 1 h and all molted within 22 h. The megalopa fed with Artemia nauplii, shrimp meat and pelleted food molted into the first juvenile stage with no exopodite after approximately 17 days. The average carapace lengths of prezoea, megalopa and the first juvenile stage were 3.2, 3.6 and 4.4 mm, respectively. The survival rate from hatching to the first juvenile stage was high (90–100%). This lobster may be the only known nephropid species with no zoeal stage. 相似文献
9.
Henningsen AD Murru FL Rasmussen LE Whitaker BR Violetta GC 《Fish physiology and biochemistry》2008,34(4):437-446
Levels of reproductively-related steroids were determined in captive male sand tiger sharks, Carcharias
taurus, maintained at two institutions: SeaWorld Adventure Park Orlando and the National Aquarium in Baltimore. Sexual conflicts
were absent at the former, but were documented at the latter. Serum titers of 17β-estradiol, progesterone, testosterone, and
5α-dihydrotestosterone were determined via radioimmunoassay in adult male sharks from 1988 to 2000. Sampling overlap between
the two institutions occurred for 3 months of the year, but steroid concentrations were compared only for April due to the
occurrence of sexual conflicts in the sharks at the National Aquarium in Baltimore in that month. For April, testosterone
and dihydrotestosterone were significantly higher in the SeaWorld males, and progesterone was significantly higher in the
National Aquarium in Baltimore males, while estradiol was not significantly different. Steroid levels were also determined
from serial samples taken monthly over 17 months from three male sharks and one female shark at the National Aquarium in Baltimore
in 2001–2002 and were compared with corresponding observed sexual conflicts. The steroid levels obtained showed distinct annual
hormonal cycles in the male sharks and corroborated a biennial cycle for the single serially-sampled female shark. Furthermore,
the steroid levels for individual males correlated with sexual conflicts as well as their position within the male dominance
hierarchy. As this species is depleted in some regions globally, insight into the steroid profile of mature sand tiger sharks
is important for a greater understanding of the relationship between their reproductive physiology and behavior, and may aid
in captive management and reproduction.
L. E. L. Rasmussen—Deceased. 相似文献
10.
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
11.
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13.
Pipadchaya Supannapong Teerayut Pimsalee Teerasak A-komol Arunee Engkagul Uthaiwan Kovitvadhi Satit Kovitvadhi Krisna Rungruangsak-Torrissen 《Aquaculture International》2008,16(5):437-453
Hyriopsis (Hyriopsis) bialatus has been cultured during the mussel life cycle from glochidia to the adult stage with a low total survival of 6% up to 130-day-old
juveniles. The main digestive enzymes (amylase and proteinases) were not detectable in one-day-old juveniles, and increased
during development. The stomach, including digestive glands, was the major digestive organ for both carbohydrate and protein.
The optimum conditions for amylase activity were 40°C and pH 7; for acidic proteinases they were 60°C and pH 5. Two main alkaline
proteinases were found in the intestine, with optimum conditions of 30°C and pH 8 and 60°C and pH 8. To improve mussel survival
by finding suitable phytoplankton species and age as food for juveniles and adults, an in-vitro digestibility test was performed
on ten algal species three and seven days old using amylase and proteinases in crude enzyme extracts from different mussel
life stages. Among the phytoplankton selected, the three most efficiently digested by juveniles were seven-day-old Chlorella sp.2, seven-day-old Chlorococcum sp. and seven-day-old Kirchneriella incurvata, in the ratio 1:1:3 for 30-day-old juveniles and 3:1:1 for 130-day-old juveniles. For the adult mussel, three-day-old Chlorella sp.2, seven-day-old Coccomyxa sp., and seven-day-old Monoraphidium sp., in the ratio 3:1:1, were the most digestible phytoplankton. Levels of in-vitro digestibility were related to the quality
(not the concentrations) of carbohydrate and protein in the phytoplankton mixtures, and protein digestibility seemed to be
the key factor determining food quality for the mussel. 相似文献
14.
Low-salinity tolerance of juvenile fugu <Emphasis Type="Italic">Takifugu rubripes</Emphasis> 总被引:1,自引:0,他引:1
ABSTRACT: To study the adaptability of juvenile fugu Takifugu rubripes to low-salinity environments, fish were transferred from full-strength seawater (100% SW) to freshwater (FW) and 25, 50, 75 and 100% SW, and checked for mortality over 3 days. No mortality was observed in 25–100% SW, whereas all fish died in FW. In fish transferred to 25–100% SW, blood osmolality was maintained within a physiological range. To further explore the lower limit of salinity that fugu could tolerate, fish were transferred from 100% SW to FW and 1, 5, 10, 15 and 25% SW. All fish survived in 5–25% SW, but fish died in FW and 1% SW. In fish surviving transfer to FW and 1 and 5% SW, blood osmolality was decreased to a near sublethal level of approximately 300 mOsm/kg·H2 O. Therefore, the lower limit of salinity tolerance is estimated to lie between 5 and 10% SW. Preacclimation in 25% SW for 7 days did not essentially affect the survival salinity range. Although survival rates and blood osmolality were slightly improved by preacclimation in 25% SW, blood osmolality was markedly decreased in salinities less than 10% SW, as was seen in the direct transfer. Neither chloride cell morphology nor sodium-potassium adenosinetriphosphatase activity in the gills showed a significant change following transfer to low salinities. These findings indicate that fugu can be adapted to hypoosmotic environments to some extent, exerting hyperosmoregulatory ability, although chloride cells are less likely to absorb ions in hypoosmotic environments. 相似文献
15.
Marianna Vaz Rodrigues Claire Juliana Francisco Gianmarco S. David Reinaldo José da Silva Maria Fernanda Falcone-Dias João Pessoa Araújo Júnior 《Aquaculture International》2018,26(1):127-138
Francisella noatunensis orientalis is a bacterium that causes emerging bacteriosis in Nile tilapia (Oreochromis niloticus) in many parts of the world, including Brazil. It is a non-motile, Gram-negative, strictly aerobic, facultative intracellular coccobacillus. This species of bacteria is responsible for low to high mortality in fish farms, causing economic losses for fish farmers. This study aimed to detect the presence of F. noatunensis orientalis using qPCR (real-time polymerase chain reaction) and to describe lesions caused by the bacterium in O. niloticus in Brazilian aquaculture. For this purpose, 360 fish from six fish farms (30 per farm) were sampled at two time points (n = 180 per sampling). Necropsies and histopathology were performed for lesion observation, in addition to qPCR and sequencing for detection and identification of Francisella species. Environmental data were collected using a multiparameter sonde YSI EXO2. All measured limnological variables were within the optimum range for cultivation of Nile tilapia. The major lesions present were melanization of the skin, splenomegaly, granulomas, and inflammatory cell responses. The prevalence of francisellosis varied from 0 to 86.66% between time periods and fish farms analyzed, and an outbreak was observed during the second sampling period. This study describes the prevalence of francisellosis in O. niloticus and reports that the lesions found are not exclusively associated with this bacterial disease. 相似文献
16.
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
17.
R. M. Rico M. T. Tejedor-Junco S. T. Tapia-Paniagua F. J. Alarcón J. M. Mancera F. López-Figueroa M. C. Balebona R. T. Abdala-Díaz M. A. Moriñigo 《Aquaculture International》2016,24(4):965-984
Partial substitutions of fish meal by 5, 15, or 25 % of Gracilaria cornea or Ulva rigida in experimental diets were evaluated to study their effects on biodiversity of intestinal microbiota composition in gilthead seabream (Sparus aurata) juveniles. The diets were offered to duplicate groups of 15 juvenile fish (14.0 ± 0.5 g) for 70 days, and at the end of the experiment the intestinal microbiota from four specimens of each treatment was analysed by denaturing gel gradient electrophoresis. Results showed that the substitution of fish meal by algae meal induced important modifications in the intestinal microbiota community, as a big reduction of the biodiversity when the highest percentage (25 %) of U. rigida was included. On the contrary, an increase on the number of species was detected when a 15 % of algae was included. Various Lactobacillus delbrueckii subspecies were selectively stimulated when G. cornea was included in the feed, and other bacterial species, such as those included in the Vibrio genus, were reduced. 相似文献
18.
P. Domingues S. Garcia I. Hachero-Cruzado N. Lopez C. Rosas 《Aquaculture International》2010,18(3):487-499
The effects of two alternative prey (crayfish and hake) were tested on growth and survival of both juveniles and adults of
Octopus vulgaris in two experiments. Octopuses fed the control (squid) were larger (3.0 ± 0.7 kg) than those fed crayfish (2.4 ± 0.6 kg) at
the end of experiment I. Similarly, overall growth rates were higher for octopuses fed squid (1.7 ± 0.3 and 1.2 ± 0.2 %BW day−1, respectively). Average feeding rates for the experiment were not different, being 6.5 ± 0.9 and 7.5 ± 0.9 %BW day−1, respectively, for octopuses fed either squid or crayfish. Nevertheless, food conversions for the experiment were higher
(42.4 ± 2.7%) for octopuses fed squid compared to the ones fed crayfish (23.9 ± 1.9 g). For experiment II, hake and crayfish
were compared to squid; the final weight of octopuses fed squid, hake or crayfish was 1,183.0 ± 242.7 g, 1,175.6 ± 240.1 g
and 922.3 ± 160.1 g, respectively. Overall growth rates for the experiment were 1.9 ± 0.2 %BW day−1, 1.9 ± 0.3 %BW day−1 and 1.1 ± 0.3 g, respectively. Final weight and growth rates were never different (P > 0.05) between octopuses fed squid and hake, but were always higher (P < 0.05) compared to the ones fed crayfish. Average feeding rates for experiment II were similar for the three diets, and
of 4.6 ± 1.5, 4.2 ± 1.3 %BW day−1 and 5.1 ± 0.9 %BW day−1, respectively, for octopuses fed squid, hake or crayfish. Food conversions for experiment II were of 41.0 ± 9.6%, 40.5 ± 9.9%
and 21.3 ± 7.4 g, respectively, for octopuses fed squid, hake or crayfish, and were always higher for octopuses fed squid
and hake compared to crayfish. The results indicate that crayfish is not an adequate replacement for the usual prey to fatten
octopus, even considering its much lower market price. 相似文献
19.
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
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