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1.
We have examined the effects of Tribulus terrestris (TT), a non-toxic herb, on sex reversal in the Convict Cichlid Cichlasoma nigrofasciatum with the aim of introducing a new environmentally friendly method for masculinization in C. nigrofasciatum. TT is a natural plant product that elevates the testosterone levels in humans and animals. Different concentrations (0.0,
0.10, 0.20 and 0.30 g/l) of TT extract were tested for their effect on sex reversal in C. nigrofasciatum by immersing newly hatched offspring once weekly for 2 months in TT extract. Of the dosages used in the present study, 0.30 g/l
TT was the most effective in terms of masculinization, resulting in a maximum male ratio of 87.23% (P < 0.001). Sex ratios of 79 and 85% at 0.10 and 0.20 g/l TT, respectively, were also significantly different from the expected
1:1 ratio (P < 0.001). Histological examinations revealed that the testes of fish treated with TT extract contained all stages of spermatogenesis,
clearly demonstrating that the administration of TT extract to C. nigrofasciatum stimulated spermatogenesis. Total survival rates in all treatments and the control were uniformly high, ranging from 88.57
to 90% (P > 0.05). We concluded that TT had no negative effect on the survival rate of C. nigrofasciatum. In addition, all groups of TT-treated fish exhibited successful growth acceleration compared to the control group, but only
the 0.30 g/l TT treatment significantly improved the growth rate of C. nigrofasciatum. (P < 0.01). Sex reversal in C. nigrofasciatum demonstrated that TT-treated 0-day-old larvae showed successful sex reversal, spermatogenesis and a better growth rate than
untreated progenies. 相似文献
2.
Shion Kawai Yuuki Takada Shinji Tsuchida Ryusuke Kado Junji Kimura 《Fisheries Science》2007,73(4):902-906
From the two species of bivalves, Calyptogena soyoae around a cold seep and Bathymodiolus septemdierum near hydrothermal vents in the sea, sterols were isolated using high-pressure liquid chromatography analysis of the lipid
fraction guided by characteristic 1H NMR signals of the sterol skeleton. The minor sterol composition of C. soyoae included 24-methylenecycloartanal, cycloeucalenol, and obutusifoliol, which are known phytosterols. From B. Septemdierum, lathosterol and cholesterol as main sterols together with more diverse sterols were obtained. The difference between these
species and their sterol contents is most likely because of feeding modes and metabolism of nutrients from their habitat. 相似文献
3.
In order to understand growth features of pearl oysters in the genus Pinctada, i.e. Pinctada fucata, Pinctada margaritifera, and Pinctada sugillata in Taiwan, a total of 3062 wild individuals of these species from juvenile to adult were collected monthyly from March 2001
to April 2002 in Jukeng, Pingtung County, south-west Taiwan. Quantitative measurements of live oysters were conducted for
shell height (SH), shell length (SL), shell width (SW), hinge length (HL), and wet weight (WW). Different cohorts were identified
through multiple length frequency analysis on SH of P. fucata and P. margaritifera, and growth curves with seasonal variation were estimated for these species. Pinctada fucata in Taiwan had a different seasonal growth pattern from the Japanese population, but had similar growth rates during the high
growth period. The growth rate of P. margaritifera in Taiwan was slower than in French Polynesia, the Solomon Islands, and the Red Sea. Comparisons of morphological growth
features among the three species show large differences in the SW-related features. Pinctada fucata in Taiwan had larger SW than in Japan and Korea. The differences in growth rates and morphological features suggested that
the wild Taiwanese oysters may retain genetically pristine characteristics, thus genetic conservation might be urgently needed. 相似文献
4.
The ark shell Anadara granosa is a species peculiar to the Ariake Sound. To determine why distribution of A. granosa in Japan is largely confined to this area, we examined feeding and growth of A. granosa as functions of environmental and biological variables. The results were compared with those of another ark shell Scapharca subcrenata, which is ubiquitous in Japan. Feeding experiments indicated that A. granosa is eurythermal and euryhaline, as is S. subcrenata, but is adapted to temperature slightly higher than S. subcrenata. Weight-specific clearance rate (CR) of A. granosa as a function of soft-body dry-weight (w) followed the power function of w (CR=2.7×w
−0.37), with coefficient and exponent very close to those for S. subcrenata. Growth rate of A. granosa increased linearly with daily ration, similar to S. subcrenata. Thus, feeding and growth characteristics of A. granosa were comparable to those of S. subcrenata and no ‘peculiarities’ of the former were detected. Therefore, the factors that make A. granosa a species restricted to the sound are probably not directly related to feeding or growth characteristics. 相似文献
5.
Gao Zexia Wang Weimin Yang Yi Khalid Abbas Li Dapeng Zou Guiwei James S. Diana 《Fish physiology and biochemistry》2007,33(3):213-222
The peripheral blood cells of one-year-old Chinese sturgeon (Acipenser sinensis) have been studied by light microscopy and transmission electron microscopy. The erythrocyte count was 84.86 × 104 cell mm−3 in the peripheral blood of the fish and that of leukocytes was 2.24 × 104 cell mm−3. The erythrocytes and four main types of leucocyte—thrombocytes, lymphocytes, granulocytes (including neutrophils and eosinophils),
and monocytes, were identified in the peripheral blood. In addition to normal erythrocytes, reticulocytes and division of
erythrocytes were observed. Thrombocytes were the most numerous among the leukocytes, and the number of neutrophils with lobated
nuclei was larger than for other fish. The structures of the erythrocytes, lymphocytes, monocytes, granulocytes, and thrombocytes
of the fish were studied. The erythrocytes were almost completely devoid of organelles, except for some mitochondria and granules.
A large number of vacuoles and a few organelles were observed in cytoplasm of the monocytes. There were many microvilli on
the membrane and pseudopodia-like cytoplasm bulge in the lymphocytes. The neutrophils were round or oval in shape with bilobed,
trilobed, or multilobed nuclei whereas the eosinophils had big special granules, dark stained. There were many vesicles in
some thrombocytes, which were related to its phagocytosis; some thrombocytes had almost no cytoplasm or organelles. 相似文献
6.
Mitsuhiro Nakaya Tetsuya Takatsu Mikimasa Joh Masayasu Nakagami Toyomi Takahashi 《Fisheries Science》2007,73(1):112-122
An investigation was conducted to evaluate the annual variation in potential predation impact (PPI) on larval and juvenile
Pseudopleuronectes yokohamae by Crangon uritai in Hakodate Bay using predator-prey size relationships. Laboratory experiments were designed to estimate the favorable prey
size of C. uritai through back-calculation of body length (BL) of P. yokohamae from sagittal otolith diameter observed in the stomachs of C. uritai. The most favorable prey-predator size ratio (BL of P. yokohamae-total length (TL) of C. uritai) class was 0.15–0.19, and ranged from 0.12–0.31. There was a significant positive correlation between the BL increase of
P. yokohamae and the bottom water temperature in the field, such that BLs stagnated during the cold year of 1999 from April to June, and
increased during the warm year of 2002. In contrast, no significant correlation was found between the TL increase of C. uritai and the bottom water temperature. Moreover, there were no significant differences in the mean TL of C. uritai between months (April–June) or years (1998–2002). Variation of PPI depended on the relationships between the growth rates
of P. yokohamae and bottom water temperature. Therefore, the warm year of 2002 resulted in higher potential predation impact (PPI≥20), and it was at least 20 days shorter than that of the cold year of 1999. These results suggest that increased bottom
water temperature in the nursery area was one of the most important factors for cumulative predation loss. 相似文献
7.
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
8.
J. W. Huang L. X. Tian Z. Y. Du H. J. Yang Y. J. Liu 《Fish physiology and biochemistry》2007,33(2):167-172
This study was conducted to evaluate the effects of dietary thiamin on the physiological status of the juvenile grouper, Epinephelus coioides. Graded levels of thiamin (0.08, 0.50, 2.12, 3.15, 4.63, 12.37 mg thiamin kg−1 diet) were fed to grouper juveniles (mean weight: 16.97 ± 0.14 g) for 10 weeks. Although fish fed the thiamin-deficient (TD)
diet showed no obvious symptoms of thiamin deficiency or increased mortality, those fed the lowest doses of thiamin (0.08
and 0.50 mg thiamin kg−1 diet) had significantly decreased transketolase activity in the liver. In addition, the level of liver thiobarbituric acid
reactive substances in fish fed the TD diet was 33–67% higher than that in fish with the thiamin-supplemented diet. There
were no significant differences in superoxide dismutase activity between the different groups of fish. 相似文献
9.
Ryoma Kamikawa Isao Masuda Kenichi Oyama Sadaaki Yoshimatsu Yoshihiko Sako 《Fisheries Science》2007,73(4):871-880
In this study, nuclear ribosomal RNA gene internal transcribed spacer regions and the cox2-cox1 fragment of the mitochondrial (mt) genome were sequenced in 24 strains of Chattonella spp. Variability in both regions showed that the mt genome sequences of Chattonella spp. have a higher evolutionary rate than the nuclear rRNA gene sequences. A maximum likelihood tree based on the mt sequence
grouped the Japanese Chattonella strains into two groups (Groups A and B), although no correlation was observed amongst the phylogenetic groups, their morphologies,
or the isolated areas. Groups A and B were clearly identified by a polymerase chain reaction-restriction fragment length polymorphism
(PCR-RFLP) assay using Fokl, without the need for a sequencing experiment. The PCR-RFLP assay revealed that Chattonella cells obtained from sea water in Oita, Japan, in 2004 and 2005 belonged to Group B. This is the first report showing the
genetic variation in Chattonella spp. using a PCR-RFLP identification protocol. 相似文献
10.
Trans geometric isomers of eicosapentaenoic acid (TEPA) have been found as minor components in human platelets. However, there
is little information on the mechanism of trans-isomerization of eicosapentaenoic acid (EPA) in vitro and in vivo. The effects of reactive radicals and heat on trans-isomerization of EPA were examined. Trans-isomerization occurred when EPA ethyl ester reacted with nitrogen dioxide radical (NO2) but not with 2,2′-azobis(2,4-dimethylvaleronitrile). TEPA was also produced from EPA ethyl ester heated at 200°C for 60
h. No TEPA, however, was detected in sardines Sardinops melanostictus after boiling, roasting, or microwave heating. These results suggest that EPA is trans-isomerized by NO2
in vivo while trans-isomerization of EPA does not occur during conventional cooking. 相似文献
11.
Hongxia Liu Meiqin Yi Xueyan Shi Pei Liang Xiwu Gao 《Fish physiology and biochemistry》2007,33(1):29-34
The substrate specificity of brain acetylcholinesterase (AChE) in adult Carassius auratus fish and its sensitivity to carbamate insecticides were investigated in vitro. The results showed that the order of four
substrates hydrolyzed by brain AChE in C. auratus was acetylthiocholine iodide > β-methylthiocholine iodide > propionylthiocholine iodide > butyrylthiocholine iodide, and
the maximum velocity (V
max) of AChE hydrolyzing acetylthiocholine iodide (ATCh) was the highest among the four substrates, and the V
max values were 0.067 and 0.082 mmol min−1 mg−1 for male and female fish respectively. But their Michaelis–Menten constants (K
m) were the lowest, only 0.071 and 0.072 mmol/l respectively. Compared with other carbamate insecticides, the sensitivity of
brain AChE to carbofuran was the highest and the IC50 values were 1.04 × 10−6 mol/l for females and 1.17 × 10−6 mol/l for males. The inhibitory tendencies of eserine, methomyl, and aldicarb to brain AChE were very similar, and the percentage
inhibition increased with time at the concentration of 1 × 10−6 mol/l. The order of inhibition potential of the three inhibitors from the highest to the lowest was eserine, aldicarb, and
methomyl. 相似文献
12.
Imtiaz Ahmed 《Aquaculture International》2007,15(5):337-350
An eight-week feeding experiment was conducted to quantify the dietary threonine requirement of young catfish, Heteropneustes fossilis (9.20 ± 0.85 cm, 3.60 ± 0.45 g) using isonitrogenous and isoenergetic diets [40% crude protein (CP); 4.28 kcal g/100 g, gross
energy (GE)] containing casein, gelatin and l-crystalline amino acids. Six dietary treatments supplemented with graded levels of l-threonine (0.50, 0.75, 1.00, 1.25, 1.50 and 1.75 g per 100 g, dry diet), in gradations of 0.25 g per 100 g dry diet were
formulated. Fish were randomly stocked, in triplicate groups, in 55-l indoor polyvinyl flow-through circular tanks and fed
experimental diets at 4% of their body weight divided over two equal feedings at 08:00 and 16:00 hours. Feeding schedule and
ration size were worked out prior to the start of the feeding trial. Live weight gain (263%), feed conversion ratio (FCR)
(1.35) and protein efficiency ratio (PER) (1.85) were significantly higher (P < 0.05) in fish fed a diet containing 1.25% dietary threonine. However, second-degree polynomial regression analysis of live
weight gain, FCR, PER and body protein deposition data indicated the dietary threonine requirement to be 1.37, 1.26, 1.23
and 1.24 g per 100 g of dry diet, respectively. Whole-body moisture decreased significantly (P < 0.05) with the increase of dietary concentration up to 1.25%. A significantly (P < 0.05) higher protein content was evident in fish fed a diet containing 1.25% threonine. Body fat increased significantly
(P < 0.05) with the increase of dietary concentration and was found to be highest at a 1.75% threonine concentration. A significantly
(P < 0.05) higher ash content was reported at the 0.50 and 0.75% threonine levels. Body protein deposition was also found to
be significantly (P < 0.05) higher at the 1.25% threonine level, followed by the 1.50% threonine level. Based on these results, it is recommended
that the diet for fingerling H. fossilis should contain threonine at a level of 1.27 g per 100 g of dry diet, corresponding to 3.17 g per 100 g of dietary protein
for optimum growth and efficient feed utilization. No mortality was observed during the experiment. 相似文献
13.
The time-course changes in calcium and phosphorus contents, dry weight, and area during scale regeneration in the goldfish,
Carassius auratus L. were quantified. Histological observations were then conducted to understand the mutual relationship between the quantitative
and morphological processes of scale regeneration. The quantitative study revealed that regenerating scales grow most rapidly
in area during the first 5 days of regeneration. The gradual decrease in the area growth rate coupled with the continuous
linear weight growth over the period of 5–28 days suggests a shift in growth priority from area growth to the apposition,
of the basal plate. Calcium and phosphorus deposition proceeded almost linearly during scale regeneration. Calcification of
the bony layer preceded that of the basal plate and, after 14 days of regeneration, calcification of the basal plate started
and gradually progressed. On day 28, recovery of calcium and phosphorus contents in the regenerating scales were approximatley
72% of ontogenetic scales, which is lower than the rates of area and weight regeneration (104 and 85%, respectively). Late
initiation and slow progress of calcification in the basal plate is suggested to be responsible for the slow regeneration
in calcium and phosphorus contents. 相似文献
14.
Tetsuya Takatsu Yuusuke Suzuki Akiko Shimizu Kazuo Imura Yuko Hiraoka Naonobu Shiga 《Fisheries Science》2007,73(1):142-155
To clarify the feeding strategy of pelagic larvae of stone flounder in Mutsu Bay, the dietary composition and pray size was
investigated from February to April during 1989–1999. Diets were compared with the numerical and volumetric compositions and
frequency of occurrence of each prey species. Mensuration formulae were applied to estimate individual prey volume in the
diet, while the length of planktonic species was measured from net and water samples. Prey shapes were assumed as sphere,
cylinder, ellipsoid, pyramid, two elliptical cones, or a combination of ellipsoid and cylinder. Prey-size range increased
as the larvae grew. Preflexion larvae fed mainly on copepod nauplii. Flexion and postflexion larvae ingested primarily appendicularians,
with a suggestion that these larvae might depend on some parts of the microbial food web. Low frequencies of flexion and postflexion
larvae with empty guts (1.7 and 1.4%, respectively) might be derived from feeding on slow-swimming appendicularians. From
a size comparison between ‘house’-like organ length and trunk length of the appendicularian Oikopleura sp., almost all house-like organs with trunks in the larval diet were nonexpanded ‘house rudiments’, not expanded ‘houses’.
Thus, stone flounder larvae may not chew the houses, but swallow the house rudiments with trunks. 相似文献
15.
16.
M. E. Garci J. E. Trigo S. Pascual A. F. González F. Rocha A. Guerra 《Aquaculture International》2007,15(1):19-24
The presence of the non-indigenous species, the black-pygmy mussel Xenostrobus securis, is reported here for the first time in an intense shellfish farming area off Galicia (NW Spain). Very high concentrations
of this mytilid bivalve have colonized estuarine waters located at the inner part of the Ria de Vigo. The invasive role of
X. securis is discussed in the context of the wide ecological tolerance of the species and the recent finding of settlements of this
species on numerous colonies of the economically-important blue mussel Mytilus galloprovincialis. The mode of introduction of the black-pygmy mussel is also discussed in relation to human management activities. 相似文献
17.
Yoshinobu Hiraoka Yoshitada Sasaki Toshiaki Takai Akihiro Kawakubo Syojiro Miyoshi Shigeru Nakajima 《Fisheries Science》2007,73(6):1383-1387
ABSTRACT: Free and total histidine contents in the muscle of various fishes and invertebrates caught in the Seto Inland Sea were estimated. These contents were higher in the muscles from skipjack, yellowfin tuna, yellowtail and mackerel than in those from lizard fish, sea bream and hairtail. Invertebrate muscles, except squid, contained low free and total histidine. Boiled and dried anchovy ( niboshi ) contained lower free histidine than that of dried anchovy (suboshi). To prepare free histidine-rich extracts, the waste residue of soup stock from smoke-dried and shaved skipjack ( katsuobushi ) was digested with proteases. The extract of the enzyme digest contained high free histidine and was used to fortify niboshi with free histidine. If taken, the fortified niboshi may suppress food intake, and prevent obesity. 相似文献
18.
Larval rearing experiments were conducted to examine the potential for mass seed production of the snow crab Chionoecetes opilio using a total of eight 20-kL tanks. Tanks were equipped with agitators, which move the water using a rectangular blade to
prevent the zoeas sinking to the bottom of the tank. Larval rearing water was treated with sodium nifurstyrenate once a week
to reduce the chance of larval infection by pathogenic bacteria. Zo eas were fed with rotifers and Artemia nauplii. A total of 122 830 megalops and 16 660 first-stage crabs were produced. Thus, the potential for mass seed production
of snow crab was determined. Survival rates up to the megalopal stage were high in tanks with a feeding regime that fed rotifers
to larvae through an entire zoeal stage. This study also describes the fatty acid composition of snow crab larvae. It revealed
that the first zoeas had a high DHA content and DHA/EPA ratio, but these values significantly decreased in the second stage
zoeas and megalops. Improving the DHA content and/or DHA/EPA ratio of larvae should be important in studies on mass seed production
technology of the snow crab. 相似文献
19.
Ana Matus de la Parra Antonio Rosas Juan Pablo Lazo Maria Teresa Viana 《Fish physiology and biochemistry》2007,33(3):223-231
The digestive enzyme activities of Pacific bluefin tuna Thunnus orientalis were evaluated for specific activity and characterized for pH and temperature optima in crude extracts of stomach, caecal
mass, and proximal, middle and distal intestine. A higher level of alkaline proteolytic activity was detected in the caecal
mass than in the proximal intestine. Total alkaline proteases, trypsin, chymotrypsin and leucine aminopeptidase (LAP) were
tested. The temperature and pH analyses showed that proteolytic activity as well as lipase were maximal in the alkaline range,
with a maximum at pH 9.0 and at temperatures between 35 and 60°C, except for the pepsin, which showed maximum activity at
the same temperatures but in the acid range (pH 3.0). The α-amylase activity showed a broader range in activity, both for
pH and temperature, with higher activity over the alkaline pH values and higher temperature. The lipase activity seems to
be nondependent on bile salts under our assay conditions, resulting in a significant activity reduction in the presence of
bile salts. This knowledge will allow the development of a gastrointestinal model (everted intestine) where food or feed will
be hydrolysed with the fish’s own enzymes, a project that is being undertaken in our laboratory as a contribution to the development
of novel diets for tuna fish. 相似文献
20.
Kui You Caihua Ma Huiwang Gao Fengqi Li Meizhao Zhang Yantao Qiu Bo Wang 《Aquaculture International》2007,15(6):479-488
The jellyfish is a popular seafood in eastern and southern Asian nations where there is a high market demand that stimulates
large-scale jellyfish production. Due to its economic importance in China, many biological studies have focused on the jellyfish
Rhopilema esculentum Kishinouye in terms of the environmental impact of aquaculture activities and culture techniques. In recent years, the commercial
aquaculture of R. esculentum has expanded greatly in China. This paper summarizes the current status of research in China on R. esculentum and associated aquacultural practices, focusing on a number of related technological approaches. 相似文献