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1.
Ma  Pin  Hu  Zhenyi  Li  Li  Li  Dapeng  Tang  Rong 《Fish physiology and biochemistry》2021,47(4):1313-1327
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2.
A cDNA encoding the subunit of thyrotropin (TSH) was isolated from a goldfish (Carassius auratus) pituitary gland cDNA library. By comparing the sequence with other teleost TSHs, a signal peptide of 19 amino acids and a mature hormone of 131 amino acids were predicted for goldfish TSH subunits. The resulting putative mature hormone of 131 amino acids had well-conserved cysteine positions and a putative N-linked glycosylation site; homology was 51–67% with TSHs from other teleosts, 38–43% with tetrapod TSHs, but only 27 and 29% with goldfish GTH-I and -II, respectively. We also examined the effects of thyroid hormones (TH) and thiourea (TU, an inhibitor of TH production) treatments on TSH and GTH subunit gene expressions in the goldfish pituitary gland. After thyroxine (T4) treatment, circulating T4 concentration increased and TSH mRNA level decreased. Supressing the amount of circulating T4 and triiodothyronine (T3) by TU treatment increased the TSH mRNA level. Moreover, T4 replacement therapy (simultaneous treatment of both TU and T4) caused a high level of circulating T4 and a low level of circulating T3, and a decrease in the TSH mRNA level. Thus, changing levels of circulating TH exert a negative feedback on the level of TSH subunit mRNA in goldfish in vivo. On the other hand, GTH subunit mRNA levels were not affected by changes in the levels of circulating TH.  相似文献   

3.
The food sources of the main economic animals and trophic levels of biotic communities from an optimized culture model (Rhopilema–Sinonovacula constricta–Paralichthys olivaceus–Penaeus chinensis) in a sea water pond in Donggang, Liaoning province were studied using the stable carbon and nitrogen isotopes technique. The results indicated that the values of δ13C range from (?27.28 ± 0.35) ‰ to (?16.65 ± 0.20) ‰ and the values of δ15N range from (3.68 ± 0.23) ‰ to (13.91 ± 0.26) ‰, both of which exhibited significant fluctuations. The δ13C values of P. chinensis, Macrobrachium mipponensis and P. olivaceus were comparatively higher than those of other aquaculture animals, and the δ15N values of P. olivaceus was also comparatively higher. The contribution to the food sources of aquaculture animals (Rhopilema, S. constricta, P. olivaceus and P. chinensis) was analyzed by using the IsoSource software. The results indicated that fish meat had the greatest contribution to Rhopilema, S. constricta and P. chinensis; P. chinensis had the greatest contribution to P. olivaceus, followed by the M. mipponensis. The trophic level of the biotic communities under that optimized culture model in a sea water pond was 3.54, in which P. olivaceus was in the fourth level (3.54); P. chinensis, Synechogobius hasta, Ablennes anastomella, M. mipponensis, Ditrema temmincki Bleeker, Chelon haematocheilus were in the third trophic levels; Rhopilema, Engraulis japonius, S. constricta and zooplankton (1.00) in the second trophic levels, suspended matters (0.15) including phytoplankton, bacteria, humus, etc., were in the primary trophic levels.  相似文献   

4.
One cannot seek permission to market transgenic fish mainly because there is no field test or any basic research on technological developments for evaluating their biosafety. Infertility is a necessary adjunct to exploiting transgenic fish unless completely secure land-locked facilities are available. In this study, we report the generation of a Cre transgenic zebrafish line using a cytomegalovirus promoter. We also produced fish carrying the Bax1 and Bax2 plasmids; these genes were separated by two loxP sites under a zona pellucida C promoter or were driven by an anti-Müllerian hormone promoter. We inserted a red fluorescent protein gene between the two loxP sites. After obtaining transgenic lines with the two transgenic fish crossed with each other (Cre transgenic zebrafish x loxP transgenic zebrafish), the floxed DNA was found to be specifically eliminated from the female or male zebrafish, and apoptosis gene expressions caused ovarian and testicular growth cessation and degeneration. Overexpression of the Bax1 and Bax2 genes caused various expression levels of apoptosis-related genes. Accordingly, this transgenic zebrafish model system provides a method to produce infertile fish and may be useful for application to genetically modified fish.  相似文献   

5.
The experiments on the intensive–extensive system were carried out between 2008 and 2010 in three ponds (area 310 m2, depth 1 m) serving as extensive units, where cages were placed as an intensive units (volume 10 m3) one in each pond. In the intensive units, African catfish (Clarias gariepinus) was cultured and fed with pellet whilst common carp (Cyprinus carpio) was stocked in each extensive unit and raised without any artificial feeding. Three different setups of extensive ponds were tested: the additional artificial plastic substrate for periphyton development equalled to 0, 100 and 200 % of the pond surface area (PP0 %, PP100 % and PP200 %) at feed loading level of 1.2, 1.9 and 2.8 gN m?2 day?1 in 2008, 2009 and 2010, respectively. The additional net fish yields in the extensive unit were 2.8–6.5 t ha?1 in PP0 %, 5.1–8.1 t ha?1 in PP100 % and 2.1–4.3 t ha?1 in PP200 %. The nitrogen recovery in the additional fish yields of extensive ponds, expressed as the percentage of feed load, was 5.6–6.1, 6.8–10 and 2.1–6.1 % in the treatments PP0 %, PP100 % and PP200 %, respectively. The combined fish production resulted in higher protein utilisation by 22–26 %; even this ratio can be increased by 33–45 % with periphyton application.  相似文献   

6.

In the present study, the tilapia Oreochromis mossambicus were exposed to food deprivation for a period of 6 or 12 days and changes in the luteinizing hormone (LH) immunoreactivity in the proximal pars distalis (PPD) of the pituitary gland and the testicular activity were examined. Intensely immunoreactive LH content was noticed in the PPD of the pituitary gland in the initial controls, controls on days 6 and 12, and fasting fish on day 6, whereas the LH immunoreactivity was moderate or weak in fasting fish on day 12. In addition, although the mean gonadosomatic and hepatosomatic indices among different experimental groups did not show any statistically significant difference, the mean numbers of spermatogonia, spermatocytes, and spermatids were significantly lower in food-deprived fish on days 6 or 12 compared to those of controls. The inhibition of the spermatogenesis was accompanied by the presence of abundant spermatozoa in the lumen of seminiferous tubules of the testis in food-deprived fish, whereas the occurrence of spermatozoa was relatively infrequent in initial controls and controls. Furthermore, refeeding to food-deprived fish on day 6 onwards resulted in occurrence of few intensely stained LH secreting cells and significantly higher numbers of spermatocytes and spermatids concomitant with sparse spermatozoa in majority of tubules compared to those of food-deprived fish. These results suggest that prolonged exposure to food-deprivation causes suppression of the LH secretory activity in the pituitary gland and disruption in the spermatogenesis in O. mossambicus.

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7.
We examined the effects of process and observation errors on the selection of the stock–recruitment relationship (SRR) curve using simulations. When the process and observation errors were added to both spawning stock biomass and recruitment, the results were as follows: (1) When the proportional model was set as the true SRR model, there was a high probability that the Ricker or Beverton and Holt model was selected in response to the errors; (2) When the Ricker or Beverton and Holt model was set as the true SRR model, the proportional model was seldom selected in response to the errors; (3) The proportional SRR model should be accepted as the optimum SRR model for the Pacific stock of Japanese sardine; (4) We should use an SRR model that is constructed from more than two independent variables (spawning stock biomass, environmental factors, etc.) when we discuss management of fisheries resources.  相似文献   

8.
ABSTRACT

This study provides abalone producers and consumers with price forecasting models exhibiting better performance for five classes of abalone prices based on shell size to help farmers predict abalone shipments and enhance the economic activity of consumers. First, the autoregressive-moving average (ARMA) models of abalone producer prices based on information criteria are selected. Second, the best ARMA model using out-of-sample data based on the mean squared error and mean absolute error is determined. Finally, this study compares the predictive accuracy of the better ARMA model and other ARMA models, using a modified Diebold–Mariano test. Higher forecasting accuracy is exhibited by the AR (1,3) model for 8 and 10 abalones per kilogram, the ARMA (1,0) and ARMA [(3),(1)] models for 13 abalones per kilogram, the ARMA (1,0) and ARMA [(1),(2)] models for 15 abalones per kilogram, and the ARMA (1,0) and ARMA (0,1) models for 20 abalones per kilogram.  相似文献   

9.
Thyroid hormone profiles and 5-monodeiodinase activity were determined in tilapia at different stages of early development. The results showed that both T4 and T3 were present in significant amounts in fertilized eggs. There was a steady decrease in both T4 and T3 levels during embryonic development. The levels continued to decline after hatching until around 7 days later when most of the yolk had been absorbed. The T4 level started to rise then, suggesting that the larval thyroid had begun to produce T4 at this time, which coincided with the period of faster growth of the larvae. The T3 level remained fairly constant until around 20 days after which it rose significantly. In vitro determination of 5-monodeiodinase activity (5-D activity) in the whole-body homogenates of larvae showed that the enzymatic conversion of T4 to T3 was not detectable in eggs and 3-day-old larvae but detected in 5-day-old and older larvae. There was a gradual increase in the Vmax as development proceeded indicating increasing 5-D activity during larval development. The Km values did not differ significantly in the different stages of development. These results are discussed in relation to the growth and development of the larvae.  相似文献   

10.
We examined individual growth and fatness in the 1975–2002 year classes of Japanese sardine. Samples were collected at the feeding grounds in the Pacific waters off northern Japan during drastic fluctuations in the population in the 1970s to 2000s. Growth rates for ages 1–3 of the 1979–1988 year classes, which included low-recruitment year classes subsisting during the high population levels of the 1980s, were apparently slower than for other year classes. There was no obvious trend when comparing year classes, growth during the first year of life (age 0), and maximum body length (BL) at age ≥5. The condition factors (CF, indicating fatness) for adult sardines of BL ≥19 cm in the 1979–1983 year classes during the maximum population level of the mid-1980s were significantly lower than for other year classes. However, there were no apparent trends in CF variations for small sardines of BL <19 cm. The apparent decreases in growth rate and fatness were strongly related to the cumulative sum of population abundance that each year class experienced. It is thought that insufficient food owing to the density-dependent effect of an abundant population at feeding grounds resulted in a decrease in the growth rate for small-bodied sardines that are investing their energy intake in body growth, and a decrease in fatness for large-bodied adults that are accumulating fat for the next reproduction.  相似文献   

11.
The direct impact of oxidation–reduction potential (ORP) on fish welfare and water quality in marine recirculating aquaculture systems (RAS) is poorly documented. In this study, the effects of the fish size (S1, S2, S3) and ORP level (normal, four successive levels) on the performance of European sea bass (Dicentrarchus labrax) were investigated. Three size fish were distributed into two RAS (RAS and RAS O3). Ozone was injected into RAS O3 to increase the ORP level. The ORP was stabilized to four successive levels: 260–300, 300–320, 320–350, and 300–320 mV in fish tanks during four periods (P1–4). At the last day of each period, the hematological parameters, plasma protein and mortality of sea bass were analyzed. Two-way ANOVA revealed that several hematological parameters, including pH, hematocrit, concentrations of oxygen, carbon dioxide, glucose (Glu), ionized calcium, kalium, and hemoglobin, were significantly influenced by the increased ORP levels over the experimental period. The alteration in blood Glu and plasma protein concentration showed that ORP around 300–320 mV started to stress sea bass. Once the ORP exceeded 320 mV in the tanks during the P3 period, mortality occurred even when total residual oxidants/ozone-produced oxidants was only 0.03–0.05 mg L?1 in the fish tanks. At the same time, plasma protein decreased notably due to appetite depression. After the decrease in ORP during the P4 period, mortality continued. In conclusion, the results strongly suggest that for European sea bass in RAS, the ORP should not exceed 320 mV in the tanks. Once ozonation damaged fish, the effect seemed to be irreversible. However, how ORP affected related hematological parameters still need the further investigations.  相似文献   

12.
This study investigated the relationship between ion levels (Na?, Cl?, K?, Ca2?, and Mg2?) in the fluid phase and total chyme of the contents of the gastrointestinal tract segments of freshwater and marine-estuarine teleosts collected in different salinities (0-34 ppt) in estuarine and freshwater portions of the S?o Gon?alo channel, southern Brazil. In addition, the relative contribution of feeding and osmoregulation to the ionic content of each portion of the gastrointestinal tract of fishes collected in different ambient salinities was analyzed. There was no relationship between salinity and ion levels in the fluid phase and total chyme of the segments of the gastrointestinal tract when considering all species together. However, there was a significant positive relationship between salinity and ion levels in the fluid phase and total chyme of two fish species (Micropogonias furnieri and Genidens barbus) collected in three or more different salinities. In most species, ion levels in the fluid phase and total chyme changed throughout the gastrointestinal tract, suggesting absorption, but the ionoregulatory mechanisms of the gastrointestinal tract seem to vary according to species.  相似文献   

13.
The Japanese type of set-net, Otoshi-ami, was introduced to Thailand in 2003 with the aim of assessing its feasibility as a sustainable coastal fisheries management tool for the empowerment of coastal fishers’ communities. All preparations for constructing and installing the set-net in the coastal waters off Mae Rumpheung beach, Rayong Province, Thailand, were carried out by local fishers, with technical advice and support from national and international institutions. The gear was modified and developed to suit the conditions of the fishing ground and target species. Data on the catch and sales trends in Rayong using the set-net were collected for 7 years for statistical analysis; during this period, the gear design and marketing strategies were improved. Simulation analysis for evaluating the cost–profit bases was conducted to establish a model for set-net technology transfer in Southeast Asia, based on differing numbers of fishers and operation days. The simulation results show the required size of the average daily catch to cover the total cost according to the average unit price, where the economic return point is an average catch of 128 kg, based on a unit price of 25 Baht/kg (0.83 USD/kg), with ten fishermen and a daily operation cost of 3,200 Baht (USD 106.17).  相似文献   

14.
Integrated aquaculture has been widely used for pearl production in the freshwater pearl mussel Hyriopsis cumingii farming in China, but the production technology has not reached the state of the art. This study explored the optimal stocking ratio of fish to mussel (fish–mussel) through a 90-day experiment conducted in land-based enclosures. The integrated system included pearl mussel, grass carp, gibel carp, silver carp and bighead carp, with four fish–mussel stocking ratios by number: 1:1 (R1), 2:1 (R2), 3:1 (R3) and 4:1 (R4). The pearl yield was higher in the R2 enclosures than in the R1 and R4 enclosures, whereas the fish yield was higher in the R3 and R4 enclosures than in the R1 and R2 enclosures. The phosphorus (P) utilization efficiency was higher in the R2, R3 and R4 enclosures than in the R1 enclosures. The wastes of nitrogen (N) and P enhanced with the increase of fish–mussel ratio. Regression analyses indicated that the fish–mussel ratio was 2.3:1 for the maximal pearl yield, and 3.6:1 for the maximal fish yield, and 1.6–2.3:1 for the minimal N waste, and 1.9–2.9:1 for the minimal P waste. This study indicated that the suitable fish–mussel stocking ratio was 2:1 in the integrated culture of H. cumingii, grass carp, gibel carp, silver carp and bighead carp.  相似文献   

15.
Taga  Makoto  Kamimura  Yasuhiro  Yamashita  Yoh 《Fisheries Science》2019,85(6):931-942
Fisheries Science - The effects of temperature and prey density on the recent growth rate (RGR) of chub mackerel, Scomber japonicus, were examined. Scomber spp. larvae and juveniles were collected...  相似文献   

16.
Paddlefish, Polyodon spathula (Walbaum), provide an important snagging and bowfishing fishery below Gavins Point Dam in South Dakota. During 2009–2020, snagging catch rates of paddlefish decreased below Gavins Point Dam to presumed “normal” lower pre-2004 levels, while bowfishing catch (harvest) rates significantly increased during 2000–2020. Because Paddlefish are highly migratory, both local (i.e., monthly gauge height, precipitation, and air temperature near Gavins Point Dam) and remote (difference in Mississippi and Missouri River discharge near their confluence) environmental conditions were used to explain variation in snagging catch rates and bowfishing harvest rates. Snagging catch rates were related to October gauge height, whereby deeper water in October led to decreased catch rates below Gavins Point Dam. Bowfishing harvest rates increased significantly after a 2016 regulation change moved the season from July 1 to July 31, and from June 1 to June 30, likely because water clarity was greater in June than in July. Mean annual air temperature and precipitation explained variation in bowfishing harvest rates prior to the 2016 regulation change. Our findings, the first to examine both snagging and bowfishing fisheries below Gavins Point Dam, suggest that local abiotic factors are likely more important than remote discharge for explaining variation in snagging catch rates and bowfishing harvest rates in the channelised Missouri River.  相似文献   

17.
In this study, the molecular mobility of fish flesh was measured by low field nuclear magnetic resonance (LF-NMR) relaxation. Sardine, tuna and mackerel were frozen at ?40 °C and stored for 1 day (24 h); and then these samples were thawed at room temperature (20 °C). The relaxation of water protons in fish flesh was measured for fresh (i.e., before freezing) and multi-cycle freeze–thaw samples (i.e., up to 12 times). Three domains from different pools of protons (i.e., low-mobile, medium-mobile and high-mobile) were identified from the relaxation curve. The T 2b (low-mobile), T 21 (medium-mobile) and T 22 (high-mobile) indicated the proton populations in the protein molecules, strongly bound water molecules, and weakly bound water molecules, respectively. In all cases, the relaxation time (T 2b: sardine r = 0.736 and p < 0.01, tuna r = 0.857 and p < 0.001, mackerel r = 0.904 and p < 0.001; and T 22: sardine r = 0.956 and p < 0.0001, tuna r = 0.927 and p < 0.0001, mackerel r = 0.890 and p < 0.0001) increased with the freeze–thaw cycles and it reached a nearly constant value after 6 freeze–thaw cycles. The increased relaxation time (i.e., higher mobility) up to 6 freeze–thaw cycles could be due to the increase in proton mobility. However, relaxation time (T 21: sardine r = ?0.510 and p > 0.05, tuna r = 0.162 and p > 0.5, mackerel r = 0.513 and p > 0.01) showed insignificant change with the increase of freeze–thaw cycles, which indicated minimal change in the medium-mobile protons. The results in this study revealed that the changes in proton mobility in the fish flesh during freeze–thaw cycles could be identified using T 2b and T 22 relaxation of LF-NMR.  相似文献   

18.
Tokuda  Masaharu  Oku  Hiromi 《Fisheries Science》2009,75(2):533-535
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19.
The effect of an enhanced (5%) sub-lethal UVA irradiation on the total metabolism of a sub- tropical convict cichlid (Cichlasoma nigrofasciatum) is described. The specific oxygen consumption (vo2) of related but differently treated populations was determined from 23 °C to 35 °C, to detect their tolerance limits toward environmental temperature. The experiments cover two generations (G1 and G2) of inbred derived populations. The fish were measured at different stages of development covering the period before and after maturation. The fish were grown at and adapted to 27–29 °C. The results showed that the population which was grown under an enhanced UVA irradiation since hatching (G2-UVA) had developed a general metabolic depression (MD) at all ranges of experimental temperature. The MD was especially expressed after the fish reached maturation. No MD was shown for the non-irradiated control populations (G2-control and G1-control) nor for the mature fish of G1-UVA. The G1-UVA population was grown under an enhanced UVA irradiation from 4 months of age. The vo2 increased with increasing temperature, reaching a maximum at 31–33 °C for the G1- and G2-control populations. For the G1-UVA, a small peak of vo2 was obtained at 29 °C reaching its maximum level at 33 °C. For the G2-UVA population, a maximum vo2 was reached at 33 °C for the young and mature fish and at 29 °C during the maturation period. It can be concluded that the accumulation of UVA irradiation from early life was responsible for the MD in this fish. A wider temperature tolerance observed in the G2-UVA population might possibly be due to a reduction of total metabolic activity. The mechanisms underlying the MD observed in this fish are not yet known, but natural selection and adaptation processes might be involved.  相似文献   

20.
《水生生物资源》1998,11(1):53-59
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