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1.
In this study we examined the endocrine mediation between environmental factors (temperature and photoperiod) and the brain–pituitary–gonadal
axis in females of pejerrey Odontesthes bonariensis. Changes in the expression of brain gonadotropin-releasing hormones (GnRHs) and gonadotropin (GtH) subunit [follicle stimulating-β
(FSH-β), luteinizing hormone-β (LH-β), glycoprotein hormone-α (GPH-α)] genes, plasma gonadal steroids [estradiol (E2) and testosterone (T)], gonadal histology, and gonadosomatic index (GSI) in adult females exposed to combinations of short-day
(8 h) or long-day (16 h) photoperiods and low (12°C) or high (20°C) temperatures after winter conditions (8 h light, 12°C)
were analyzed. Pejerrey females kept under the short photoperiod had low GSIs, and their ovaries contained only previtellogenic
oocytes regardless of the experimental temperature. In contrast, females exposed to the long photoperiod had high GSIs and
ovaries with vitellogenic oocytes at both temperatures. These fish also showed a significantly higher expression of sGnRH,
pjGnRH, cGnRH-II (the three different GnRH variants found to date in the pejerrey brain), FSH-β, LH-β and GPH-α genes and
plasma E2 levels than those at the shorter photoperiod. No significant changes were observed in plasma T levels. Based on these results,
we concluded that the increase in day length but not that of temperature triggers the maturation of pejerrey females after
the winter period of gonadal rest and that this occurs by an integrated stimulation of the various components of the brain–pituitary–gonad
axis. 相似文献
2.
Ryusuke Sudo Ryota Tosaka Shigeho Ijiri Shinji Adachi Hiroaki Suetake Yuzuru Suzuki Noriyuki Horie Satoru Tanaka Jun Aoyama Katsumi Tsukamoto 《Fisheries Science》2011,77(4):575-582
To improve understanding of the mechanism of early ovarian development in eels, the effects of water temperature decrease
on oocyte development, plasma levels of sex steroids [estradiol 17β (E2), testosterone (T), 11-ketotestosterone (11-KT)],
and gonadotropin β-subunit [follicle-stimulating hormone (FSHβ), luteinizing hormone (LHβ)] messenger RNA (mRNA) expression
levels were investigated. A total of 27 female Japanese eels Anguilla japonica were divided into initial, control, and test (water temperature decrease) groups. Starting on 22 September 2009, eels in
the test group were reared in a tank with gradual temperature decrease from 25°C to 15°C over 39 days, while the control group
was maintained at 25°C. The test group accumulated more oil droplets in their oocytes than did the other groups. Levels of
sex steroids, especially 11-KT, were higher in the test group. In contrast, FSHβ and LHβ mRNA expression levels were lower
in the test group. These results suggest that water temperature decrease only induced an early stage of ovarian development
that was partly affected by an 11-KT increase. For further maturation, other environmental factors related to induction of
gonadotropin increase appear to be needed. 相似文献
3.
北太平洋长鳍金枪鱼卵巢的发育特征 总被引：1，自引：0，他引：1
根据2013年10月–2014年2月在北太平洋海域(29°08′~41°08′N,163°50′~144°19′W)采集的364尾长鳍金枪鱼的卵巢样本,利用组织学分析,详细描述了长鳍金枪鱼卵巢、卵细胞的发育阶段。结果显示,北太平洋长鳍金枪鱼卵巢内同时存在不同时相的卵细胞,为分批产卵类型;组织学上,长鳍金枪鱼的卵细胞发育过程分为6个时相,卵巢发育过程分为6个时期;卵巢成熟指数在成熟期为Ⅰ~Ⅴ期时逐渐增大,在Ⅵ期时减小;北太平洋长鳍金枪鱼产卵高峰为12月中旬和1月初,其卵巢成熟指数随纬度的升高呈递减趋势,随经度变化规律不明显。研究表明,通过对北太平洋长鳍金枪鱼卵巢的发育特征的分析与探讨,可为北太平洋长鳍金枪鱼的资源状况评估及渔业可持续发展提供生物学信息。 相似文献
4.
To investigate the effect of water temperature on gamete maturation and gamete quality, European grayling (Thymalus thymallus) were held under different temperature regimes prior to spawning. Maturation of males and females and their gamete quality
depended strongly on temperature regime. The highest percentages of maturing fish and highest gamete quality were obtained
under a creek water temperature regime with natural seasonal fluctuations. In warmed creek water (3–4°C), at a constant temperature
of 8–9°C, and under an abruptly increasing temperature, regime maturation rates and gamete quality were reduced. The effect
was more pronounced in females than in males. The spawning dates of different wild Austrian grayling populations were also
correlated with water temperature data collected during the last 10–15 years. The mean spawning date expressed as the number
of days from 21 December until spawning ranged from 98 to 111 days for lower elevation populations, while it was considerably
delayed for an alpine population. All populations spawned at water temperatures of 5.5–7.2°C. Regression analysis indicated
that spawning date correlated with (1) the overall mean water temperature from 21 December until spawning, (2) the mean water
temperature during both the last 10 days and 15 days before spawning, and (3) the difference between mean January temperature
and that of the last 15 days before spawning. The regression functions indicate that an increase in water temperature from
21 December to spawning of 1°C advances spawning by 5? days, and an increase of 1°C in the last 10–15 days advances spawning
by 3? days. 相似文献
5.
Erik Vikingstad Eva Andersson Tom Johnny Hansen Birgitta Norberg Ian Mayer Sigurd Olav Stefansson Per Gunnar Fjelldal Geir Lasse Taranger 《Fish physiology and biochemistry》2016,42(3):895-907
Maturing male and female Atlantic salmon (Salmo salar L.) were held under three temperature regimes for 10 weeks between September and December: warm (constant 14–16 °C), ambient (decreasing from 11 to 5 °C), and cold (decreasing from 7 to 3 °C). Blood samples were analyzed for plasma steroid levels, and the fish were inspected for the presence of expressible milt (total volume and spermatocrit) and ovulation weekly. Samples of eggs were dry-fertilized with milt stripped from three males held at the same temperatures and incubated until the eyed stage. In females, levels of plasma testosterone (T) and 17β-oestradiol (E2) dropped as ovulation approached, concurrent with a rapid increase in levels of plasma 17α,20β-dihydroxy-4-pregnen-3-one (17,20β-P). In males, levels of T and 11-ketotestosterone (11-KT) peaked 2–3 weeks after the first appearance of expressible milt, while levels of 17,20β-P increased steadily and did not exhibit a definite peak. Exposure of females to cold water amplified and advanced the profiles of all three steroids compared with the ambient group, and increased the survival rates to the eyed egg stage. Cold water had no immediate effect on the male steroid profiles, but later, higher levels of 17,20β-P were evident compared with both the ambient controls and the warm water group, while the effects on 11-KT and T were more variable. Exposure to warm water completely inhibited both milt production and ovulation. Moreover, warm water modulated the steroid profiles of the males with lower 11-KT levels compared with ambient controls and lower 17,20β-P level compared with cold-water-treated males. In females, warm water resulted in total inhibition of the peri-ovulatory peak in 17,20β-P and prevented the normal decline of T and E2 levels associated with ovulation. The findings of the present study are highly relevant for broodstock management in aquaculture, as well in understanding the impact of climate change/temperature variability on wild salmon spawning. 相似文献
6.
Effects of temperature and photoperiod on the reproductive activity of a reef associated tropical damselfish Chrysiptera cyanea were evaluated under three phases with different environmental patterns, phase I (April–May; increasing water temperature
and photoperiod), phase II (June–July; increasing water temperature and peak/decreasing photoperiod), and phase III (August–September;
peak/decreasing water temperature and decreasing photoperiod). When the fish were reared at 20, 25, or 30°C under natural
photoperiod, the reproductive conditions differed within and among the phases depending on experimental temperature and environmental
patterns. From phases I through III, ovaries with vitellogenic oocytes were notable only at 25°C, whereas regressing and immature
oocytes were noticed at 20 and 30°C. The fish underwent active spawning at 25°C, whereas no or few spawnings were observed
at other temperatures. In phase III, there was a resultant prevention of decrease in the gonadosomatic index and disappearance
of vitellogenic oocytes in the ovaries of fish under a long photoperiod (LD14:10) compared to those under a short photoperiod
(LD10:14). These results indicate that a long photoperiod with a suitable range of water temperature is a principal determinant
in continuity of reproductive activity and performance, and that a high temperature has a negative impact on their ovarian
development. 相似文献
7.
Two year old black porgy (Acanthopagrus schlegeli) fed a diet containing 4.0 mg kg–1 of estradiol-17 (E2) for 5 months had significantly lower GSI than the control group during the spawning season. E2 suppressed testicular development, spermiation and plasma testosterone (T) and 11-ketotestosterone (11-KT) and stimulated ovarian development, vitellogenesis and sex reversal. Spermiation in the control group occurred in January and February with the concentrations of 1.08–1.36 × 1010 sperm ml–1 of milt. Higher plasma T and 11-KT, but lower E2 levels were detected in the spermiating fish (control group). Higher plasma E2 levels were detected in the sex reversing black porgy during the pre-spawning season. A sharp rise in plasma 11-KT and a drop in T levels were detected in spermiating fish (control group) from January to February. Plasma 11-KT levels correlated with the testicular development and spermiation. The data suggest that E2 plays an important role in controlling the sex reversal of black porgy.to whom correspondence should be addressed. 相似文献
8.
Zdeňka Svobodová Jana Máchová Hana Kroupová Miriam Smutná Ladislav Groch 《Aquaculture International》2007,15(3-4):277-286
Three case studies of ammonia autointoxication of the common carp (Cyprinus carpio L.) are described. In the first case, carp yearlings with a full digestive tract were transferred during the growing period
from pond water (22°C) to tap water (17°C). In the second case, marketable carp were transferred from the fishing ground of
a pond (18°C) to a storage pond (10–12°C). Harvest was performed in late September when the fish were still ingesting natural
feed. In the third case, marketable carp after storage for 1 month were transferred to storage ponds with markedly lower water
temperature. Stress because of harvest and handling also occurred in this case. In all cases, highly increased concentrations
of ammonia were found in the blood plasma of the fish (mean ± SD 1760 ± 350 μmol L−1 in the first case, 870 ± 540 μmol L−1 in the second case, and 880 ± 150 μmol L−1 in the third case). Highly congested, dark-red coloured, oedematous gills were observed for all specimens. We can avoid similar
cases of ammonia autointoxication by protection of fish from sudden changes of temperature during rearing, harvesting, and
handling. 相似文献
9.
10.
M. Pavlidis S. Keravec L. Greenwood B. Mourot A.P. Scott 《Fish physiology and biochemistry》2001,25(3):171-180
The effect of photoperiod and temperature on the timing and the quality of spawning, and on associated endocrine changes in
circulating 17β-oestradiol, 11-ketotestoserone (11-KT) and vitellogenin (Vtg) were investigated in common dentex, Dentex dentex, undergoing their second reproductive cycle. The possibility was also explored of using the measurement of steroids in the
culture water of broodstock tanks, rather than in individual blood plasma samples, as a potentially useful tool for assessing
the physiological state of a fish without disturbing them. One group of fish was exposed to a simulated natural seasonal cycle
and ambient temperature (CONTROL). The other two groups were exposed to simulated seasonal photoperiod cycles (12 month-long)
but which were phase-shifted either three months before (ADVANCED) or after (DELAYED) the natural cycle. Temperature was kept
at 19.4±0.9 °C all-year-round. In the CONTROL, spawning started in mid-April and lasted until mid-June, while in the ADVANCED
group, spawning started 4 months earlier and in the DELAYED group 2 months later than the CONTROL. The total egg production,
egg quality, hatching rate, relative fecundity, and spawning index of the experimental groups were similar to the controls.
The differences in spawning time induced by photothermal manipulation were associated with a difference in the timing of peak
concentrations of plasma E2, 11-KT and Vtg. In all three groups, the amounts of conjugated 17,20β-dihydroxy-4-pregnen-3-one (17,20β-P) and free and sulfated
11-KT which could be extracted from the water during the spawning period were significantly higher than those found in the
preovulatory period. However, the differences were mostly less than 2-fold suggesting that, at least under the conditions
employed in this study, the method was of limited use for non-intrusive detection of gonadogenesis and spawning (as had been
hoped). The observed differences in spawning time and in the seasonal changes of sex steroids and Vtg confirm and extend the
findings on marine fish.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
11.
Photosynthetic activities of seedlings of Zostera marina were successively measured using a gas volumeter for 6 days at seven light (0–400 μmol photons/m2 per s) and 11 water temperature conditions (5–35°C). The seedlings were collected from mature plants (Ise Bay, central Japan),
and stored and cultured in incubators accurately controlled at each test temperature. The maximum gross photosynthesis (P
maxg) was recorded at an optimal water temperature of 29°C after 0 days. After 6 days, P
maxg appeared at 25°C and most plants cultured at 29–30°C bleached and withered after the drastic increase of light compensation
point (I
c). On the contrary, at 5–28°C, the photosynthetic activities either changed little (5–25°C) or recovered after a temporal
reduction (26–28°C); seedlings survived and looked healthy after being cultured for 6 days. The recovery was thought to be
an acclimation to tolerate higher water temperature. As a result, the critical upper water temperature for Z. marina seedlings was proposed as 28°C. The temperature was consistent with the previously reported maximum water temperature in
habitats around the southern boundary of Z. marina in the northern hemisphere. 相似文献
12.
The movement of adult muskellunge, Esox masquinongy Mitchill, has been investigated in a variety of systems, but temperature selection by muskellunge has not been examined where well‐oxygenated waters were available over a range of temperatures for much of the year. Thirty subadult and adult muskellunge tagged internally with temperature‐sensing radio tags were tracked from March 2010 to March 2011 in a Tennessee reservoir. Mean tag temperatures were 18.9 °C in spring (March to May), 22.1 °C in summer (June to August), 16.5 °C in autumn and 9.8 °C in winter (December to February). When the greatest range in water temperatures was available (7.1–33.3 °C; May to early August 2010), their realised thermal niche (mean ± 1 SD) was 22.3 °C ± 1.8; the realised thermal niche was affected by fish size (smaller fish selected slightly warmer temperatures) but not sex. An electric generating steam plant discharging warm water resumed operation in January 2011, and most (86%) tagged fish occupied the plume where temperatures were ≈10 °C warmer than ambient water temperatures. No mortalities were observed 15 days later when plant operations ceased. Their affinity for the heated plume prompted concerns that muskellunge will be too easily exploited when the plant operates during winter. 相似文献
13.
Foss A Grimsbø E Vikingstad E Nortvedt R Slinde E Roth B 《Fish physiology and biochemistry》2012,38(2):565-571
Investigation of the physiological effects of live chilling in Atlantic salmon, Salmo salar, has been performed in two experiments. In the first, fish (mean weight 840 g) acclimatized to either 16, 8, or 4°C were
directly transferred horizontally or vertically (9 combinations) to water temperatures of 16, 8, 4, or 0°C using a dip net.
Blood samples were collected at 1 and 6 h (h) post-transfer. In the second experiment, fish (mean weight 916 g) acclimatized
to 16°C were exposed to four temperature-drop regimes (no physical handling): 16–4°C (over 5 h), 16–4°C (over 1 h), 16–0°C
(over 5 h), and 16–0°C (over 1 h). Blood samples were collected 1 h post-temperature drop. Physical transfers in the first
trial, i.e., temperature drops, resulted in immediate (1 h) increases in blood lactate concentrations at all three temperatures,
but levels were significantly reduced and close to pre-transfer levels after 6 h. Horizontal transfers, i.e., 16–16°C, 8–8°C,
and 4–4°C, resulted in similar increases and were not significantly different from the groups exposed to temperature drops.
The most severe vertical transfer (16-0) resulted in a swift loss of equilibrium and eventually death. In experiment 2, temperature
drops from 16 to 4°C and from 16 to 0°C over a period of one or 5 h, without physically handling the fish, resulted in no
significant increases in any of the measured parameters 1 h post-transfer, except in the 16–0 (1 h) group. The latter experienced
a significant increase in blood sodium, glucose, lactate, and cortisol levels compared to all other groups. The results suggest
that salmon are capable of tolerating relatively steep temperature drops without any significant negative effects on blood
stress parameters and that physical stress from handling overrides the effect of thermal insults. 相似文献
14.
M. Sala-Rabanal J. Sánchez A. Ibarz J. Fernández-Borràs J. Blasco M.A. Gallardo 《Fish physiology and biochemistry》2003,29(2):105-115
Low temperatures, and the voluntary fasting that they induce, have been implicated in outbreaks of winter syndrome in farmed
gilthead sea bream (Sparus aurata). Two experiments were performed with the objective of studying if a decrease in water temperature is sufficient to induce
this disease or some of its associated signs. In the first experiment, water temperature was either acutely or gradually reduced
to 8 °C. In the second experiment, fish were exposed to either 8 °C or 12 °C, or fasted at 14 °C.
Although no mortalities due to winter syndrome were registered during any of the experiments, some of the signs described
in affected sea bream were observed in 8 °C-exposed fish. Among the most relevant were the paleness and friability of the
liver and the occurrence of fatty degeneration in the hepatocytes.
During the experiments, the general state of health of fish was monitored by measuring hematic parameters and the plasma concentration
of proteins, glucose and ions. Low temperatures (8 and 12 °C) and fasting at 14 °C resulted in significant decreases in the
levels of the different plasma protein fractions. This drop was more important in all the 8 °C-exposed fish, due mainly to
a higher descent of albumin, α1-globulins and fibrinogen. Moreover, 8 °C-exposed fish showed a fall in total white blood cells and a rise of plasma glycemia,
as well as a significant drop of plasma potassium and calcium levels and a transient increase of plasma magnesium concentration.
In 8 °C-exposed fish, the rate of water temperature descent did not modify the profiles of change of any of the studied parameters.
These results indicate that at 8 °C gilthead sea bream are unable to maintain the levels of plasma protein fractions and ions
present in control animals.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
15.
The present paper describes the growth properties of juvenile Atlantic cod (Gadus morhua) reared at 7, 10, 13 and 16 °C, and a group reared under “temperature steps” i.e. with temperature reduced successively from
16 to 13 and 10 °C. Growth rate and feed conversion efficiency of juvenile Atlantic cod were significantly influenced by the
interaction of temperature and fish size. Overall growth was highest in the 13 °C and the T-step groups but for different
reasons, as the fish at 13 °C had 10% higher overall feeding intake compared to the T-step group, whereas the T-step had 8%
higher feeding efficiency. After termination of the laboratory study the fish were reared in sea pens at ambient conditions
for 17 months. The groups performed differently when reared at ambient conditions in the sea as the T-step group was 11.6,
11.5, 5.3 and 7.5% larger than 7, 10, 13 and 16 °C, respectively in June 2005. Optimal temperature for growth and feed conversion
efficiency decreased with size, indicating an ontogenetic reduction in optimum temperature for growth with increasing size.
The results suggest an optimum temperature for growth of juvenile Atlantic cod in the size range 5–50 g dropping from 14.7 °C
for 5–10 g juvenile to 12.4 °C for 40–50 g juvenile. Moreover, a broader parabolic regression curve between growth, feed conversion
efficiency and temperature as size increases, indicate increased temperature tolerance with size. The study confirms that
juvenile cod exhibits ontogenetic variation in temperature optimum, which might partly explain different spatial distribution
of juvenile and adult cod in ocean waters. Our study also indicates a physiological mechanism that might be linked to cod
migrations as cod may maximize their feeding efficiency by active thermoregulation. 相似文献
16.
The effects of aromatizable 17α-methyltestosterone (MT) and non-aromatizable 17α-methyldihydrotestosterone (MDHT) on sex inversion
in red-spotted grouper, Epinephelus akaara, were investigated. Fish were implanted with MT, MDHT and MT+AI (aromatase inhibitor, AI) respectively for one month. The
results showed that the three treated groups turned into transitional stage with intersex gonads, which contained atretic
oocytes and spermatogenic germ cells at all stages of spermatogenesis. The controls did not change sex. The gonads of more
than half MT-implanted fish were in early transitional stages of sex inversion, whereas those of more than half MDHT and MT+AI-implanted
fish were in late transitional stages of sex inversion. No difference in serum estradiol-17β (E2) levels between the controls and the treated groups were observed, whereas 11-ketotestosterone (11-KT) and testosterone (T)
levels increased in all treated groups. Significantly lower gonadosomatic index (GSI) and gonadal aromatase activity were
observed in the treated groups, which were in accordance with the lower mRNA expression of P450aromA. However, P450aromB mRNA
expression increased in the MT group, while it did not change in the MDHT group. These results suggest that the sex inversion
of red-spotted grouper by MT and MDHT implantation might be due to the suppression of P450aromA gene expression, and resulting
in both the decrease of the ovarian estrogen –secretion, as well as the increase in the 11-KT levels. Furthermore, the main
reason for MT being less effective than MDHT might be due to partial aromatization of MT to estrogen. 相似文献
17.
Toshihiro Wada Kyoichi Kamiyama Hiromichi Mitamura Nobuaki Arai 《Fisheries Science》2017,83(4):573-585
To elucidate the post-release movement and emigration of juvenile spotted halibut Verasper variegatus, ten hatchery-reared age-0 individuals (10 months old, 17.0–19.7 cm total length) surgically implanted with acoustic transmitters were released near the center of Matsukawa-ura, a shallow brackish lagoon, on 25 November 2009 (water temperature 13.8 °C). They were monitored by ten acoustic receivers for 5 months. Of ten individuals, eight left the release site during December–March. Three of these emigrated to the outer ocean on 17 and 29 January and 30 March 2010, respectively. Juveniles probably started wintering migration in December and January when water temperatures decreased considerably in the lagoon (mean 9.5 and 6.0 °C, respectively). They stopped their migration in the coldest month, February (mean 5.7 °C), and restarted it in March when water temperatures frequently exceeded a plausible threshold for movement (≥6 °C). Statistical analyses revealed that the fish started migration significantly more frequently at nighttime. The migration track of an individual recorded from 11 to 30 March showed gradual nocturnal movements and a slow migration speed (estimated maximum speed 2.2 m/min). Our results revealed that water temperature primarily governed the seasonal timing of nocturnal migratory movements of juvenile spotted halibut. 相似文献
18.
Vikingstad E Andersson E Norberg B Mayer I Klenke U Zohar Y Stefansson SO Taranger GL 《Fish physiology and biochemistry》2008,34(3):289-298
Atlantic salmon (Salmo salar L.) females (2 SW), maturing for the first time, were reared under one of three temperature regimes (high: 14.3 ± 0.5°C;
natural: 10.6 ± 1.0°C; and cold: 6.9 ± 1.0°C) in combination with one of two experimental treatments; an injection of GnRH
analogue (GnRHa) contained in biodegradable microspheres, or a sham injection (microspheres only). The six experimental groups
were then reared under simulated natural photoperiod for 4 weeks. Blood samples were drawn for analysis of plasma steroid
levels and the fish were inspected for ovulation weekly. Batches of stripped eggs were incubated in triplicate incubators
in raceways until the eyed stage. Treatment with GnRHa resulted in a substantial advancement and synchronization of ovulation
at all temperatures, while exposure to cold water also appeared to advance ovulation slightly. While 75% (warm and cold) to
90% (natural) of GnRHa fish ovulated during the 4-week trial, only 30% of sham-treated females exposed to cold water, and
none of the sham-treated fish held at higher temperatures, ovulated during this period. Survival rates of embryos to the eyed-stage
were significantly higher for broodstock exposed to cold water. Plasma levels of testosterone (T), 17β-oestradiol (E2), and 17α,20β-dihydroxy-4-pregnen-3-one (17,20βP) were all significantly affected by treatment with GnRHa and, to a lesser
extent, temperature. The efficiency of GnRHa in counteracting the negative effects of high temperature on ovulation and the
associated changes in circulating sex steroids suggest that temperature inhibition operates at least in part at the brain
or pituitary. 相似文献
19.
The effects of acclimation temperature and acute temperature change on the uptake and metabolism of the procarcinogen benzo[a]pyrene
(BaP) by gill cells of the gulf toadfish, Opsanus beta, were examined. BaP was rapidly accumulated by isolated gill cells and uptake rates were directly proportional to BaP concentration
in the medium (1 to 100 μg/ml). Uptake rates were higher in cells isolated from fish acclimated to 18°C when compared to cells
from 28°C acclimated fish at all incubation temperatures. When cells were exposed to BaP at the respective acclimation temperatures
of the fish, uptake rates were similar (0.14 ± 0.01 at 18°C and 0.12 ± 0.01 μg BaP/s/10 mg cells at 28°C). This finding is
discussed in view of results which showed a partial compensation of membrane fluidity in plasma membranes isolated from fish
from the two acclimation temperatures. At higher incubation temperatures, cells from fish acclimated to 18°C metabolized BaP
at a greater rate than those at 28°C (49.6 ± 1.92 and 43.0 ± 2.24 μg/g/8h, respectively, at 23°C). Low but detectable activities
of common biotransformation enzymes (aryl hydrocarbon hydroxylase, glutathione-S-transferase) and cytochrome P-450 content
were found, however, no significant differences were evident between cells from fish acclimated to different temperatures.
To whom to address correspondence 相似文献
20.
Asian Seabass which shows precocious sex inversion in cultured environment is a major impediment to maintain a proper broodstocks. Seabass grown commercially in freshwater were transported to the research facility and held in freshwater at 29°C for 4 weeks and acclimatized to the experimental conditions. Fish were daily fed with a commercial pellet (50% protein, 18 MJ kg?1) to satiety. Blood, brain and gonad collected before and at the end of the experiment were analysed for sex steroids level and aromatase activity. There was an increase in Plasma E2 levels with temperature in fish at 34°C whereas no significant difference was observed at 24 and 29°C although the highest plasma T level was detected in fish at 34°C which had significantly lower level than at the beginning, except those held at 24°C in freshwater. Plasma 11‐KT was significantly greater in fish at 24°C compared with 29 or 34°C which had clear opposite to the E2. Aromatase activity in brain was higher at 29°C than at either 24 or 34°C, whereas gonadal aromatase recorded highest at 34°C. These findings concluded that high temperature in culture facility induces sex inversion of Asian Seabass. 相似文献