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1.
ABSTRACT:   The effects of temperature and salinity on growth of green algae Chlorella ellipsoidea and Nannochloris oculata were determined to compare the optimum culture conditions. A four-temperature (15, 20, 25, and 30°C) × three-salinity (10, 20, and 30) factorial design with triplicates was applied. Specific growth rate (SGR), maximum density, and duration to reach maximum density of C. ellipsoidea were significantly affected by both temperature and salinity. The highest SGR was observed in C. ellipsoidea at 25°C and salinity 10, but the maximum density was very low. The highest maximum density was achieved in C. ellipsoidea at 15°C and 10. The slope constant of the linear relationship between semilogarithmic growth of C. ellipsoidea and day of culture was highest at 15°C and 10. The SGR and duration to reach maximum density of N. oculata were significantly affected by both temperature and salinity. However, maximum density of N. oculata was significantly affected by temperature, but not salinity. The highest maximum density was achieved in N. oculata at 25°C and 30, but SGR was significantly lower than that of N. oculata at 25°C and 10. The slope constant of the linear relationship between semilogarithmic growth of N. oculata and day of culture was highest at 25°C and 30. Based on these results, the condition of 15°C and salinity 10 seemed to be optimal for maximum density of C. ellipsoidea , and the condition of 25°C and 10 and 30 for SGR and maximum density for N. oculata , respectively.  相似文献   

2.
Tank respirometry was used to study the interactive effects of protein:lipid level (55%:11% vs. 42%:16%; both diets isoenergetic) and temperature (11, 6 and 2 °C) on the magnitude and duration of specific dynamic action (SDA) in juvenile Atlantic cod and haddock. The protein:lipid level did not affect any measured variable. However, numerous temperature and species effects were observed. For example, although the maximum post-feeding oxygen consumption (30–50% above routine metabolic rate; RMR) and SDA duration (∼55–85 h; SDADUR) were not affected by temperature, SDADUR g−1 of food increased from 11 to 2 °C (from ∼3 to 12 h g food−1). While absolute SDA (mg O2) decreased by ∼60–65% in cod and ∼75% in haddock from 11 to 2 °C, due to a concomitant decrease in food consumption from ∼2.0% to 0.6% body mass, SDA comprised between 3.3% and 5.2% of the dietary energy content at all temperatures. Finally, RMR at 11 and 2 °C and SDADUR at 2 °C were 25–35% and 25% greater in cod, respectively, as compared with haddock. These results suggest that feeding reduced protein diets at low water temperatures is unlikely to improve the growth of these species.  相似文献   

3.
The metabolic responses of different colour strains of Ruditapes philippinarum in terms of oxygen consumption and ammonia excretion to changes in temperature (15–35°C) and salinity (20–40) were investigated. In our range of temperatures (15–35°C), oxygen consumption rate (OCR) increases in cultivated strains (White and Zebra) in opposition to the effect in the wild strain which reach a maximum at 25°C. The highest Q10 coefficients were 2.741 for zebra strain, 4.326 for white strain, and 1.944 for wild at temperatures of 25–30, 30–35 and 20–25°C respectively. In our range of salinity (20–40°C), OCRs of white strain and zebra strain firstly decreased to lowest level at 25 and 30, and then increased to highest level at 35 and 40 respectively. When the salinity is beyond 35, the OCR decreased and the turning point was found in the white strain and wild, but the zebra strain OCR still increased to a highest level (1.906 mg g?1 h?1) at 40 (P < 0.05). These results show that the cultivated colour strains of R. philippinarum were different from wild in terms of metabolic responses, and information on its response to different temperature and salinity have implications in the aquaculture industry.  相似文献   

4.
Abstract Yellowfin sea bream Acanthopagrus latus (Houttuyn) (0.98 ± 0.27 g) were examined for temperature and salinity tolerances at nine different environmental regimes (0.3, 15 and 33 ppt combined with 10, 25 and 32 °C), in which the fish were subjected to gradual and sudden changes in temperature and salinity respectively. The 50% CTMax (critical thermal maximum) and the UILT (upper incipient lethal temperature) were in the range of 34.8–38.2 °C and 32.8–36.4 °C respectively. The 50% CTMin (critical thermal minimum) and the LILT (lower incipient lethal temperature) were in the ranges of 4.9–9.4 °C and 7.1–17.6 °C respectively. The 50% CSMax (critical salinity maximum) and the UILS (upper incipient lethal salinity) were in the ranges of 54–69‰ and 9–44‰, respectively. The fish at lower temperature (10 °C) and salinity of 33‰ tolerated temperature as low as 6 °C when the temperature was decreased gradually. The fish at 33 and 15‰ and lower temperature (10 °C) tolerated salinity as high as 66–67‰, whereas those at freshwater salinity level (0.3‰) and 32 °C tolerated salinity to 50‰ when salinity was increased gradually. The relationships among UILT, LILT, 50% CTMax, 50% CTMin, UILS, 50% CSMax, salinity and temperature are given.  相似文献   

5.
The effects of temperature on growth, food-conversion ratio (FCR) and feeding intensity of juvenile dusky kob Argyrosomus japonicus (23.7±2.6 g fish−1) were assessed over the temperature range 17.5–28.5 °C in a 42-day growth trial. Growth increased with increasing temperature up to an optimum after which it declined. Specific growth rates were 2.05% and 1.2% day−1 for the fastest (25.3 °C) and the slowest (17.5 °C) treatments respectively. Food-conversion ratio peaked at a lower temperature than growth. Optimal (0.72 kg kg gain−1) and least efficient (1.40 kg kg gain−1) FCR were found at 21.7 and 17.5 °C respectively. Feeding intensity was linearly related to temperature within the range of 17.5–28.5 °C. These results corresponded to the thermal preference (25–26.4 °C) and natural temperature distribution (12–28 °C) of South African dusky kob. Determination of the temperature range that does not limit growth is a prerequisite to assess the relationship between growth and environmental variables such as light intensity, feeding regime and stocking density. Consequently, experiments to determine the effects of these environmental variables on growth and aquaculture potential of dusky kob should be conducted at 24–26 °C.  相似文献   

6.
The effects of various dietary protein levels on growth performance, whole body composition and nutrient utilization were studied in two-banded sea bream ( Diplodus vulgaris ), a candidate species for aquaculture. Fish (initial weight 6.1 g) were fed to satiety six iso-energetic diets, containing 5%, 12.5%, 25%, 35%, 45% or 55% of crude protein during 72 days. Fish fed 35% and 45% protein attained better growth and feed utilization than the other groups ( P  < 0.05). Daily growth index and feed conversion ratio were the poorest for fish fed 5% and 12.5% protein ( P  < 0.001), while the 25% and 55% protein groups had intermediate performance. Lipid retention increased significantly from 13.7% to 30.1% ( P  < 0.0001) and protein retention decreased from 35.5% to 21.3% ( P  < 0.01) with increasing protein levels from 12.5% to 45%. Muscle protein, lipid and energy concentrations were not significantly affected by dietary protein level. The estimated protein requirement for maintenance and maximum growth of two-banded seabream growing from 6 to 20 g were 7.5% and 35.7%, respectively. Protein requirements as calculated from body protein gain were 2.3 and 6.5 g of protein intake per kilogram body weight per day.  相似文献   

7.
Marine periphytic cyanobacteria and diatoms have been examined as a potential source of feed supplement for rearing aquatic larvae in the aquaculture industry. Culture of the periphytic diatom Amphora sp., Navicula sp., Cymbella sp. and the cyanobacteria Oscillatoria sp. at different salinities showed significant changes in biomass and specific growth rates. Diatoms growth was significantly higher at 35 g L−1, while for cyanobacteria growth was better at 25 g L−1. Significantly higher levels of protein and lipid were found in diatoms at low salinities (15–25 g L−1) and an increase in carbohydrate at high salinities (30–35 g L−1). Conversely, cyanobacteria showed a significantly higher lipid content at 30–35 g L−1 compared with other salinity levels but no significant changes were observed in the protein and carbohydrate contents at different salinity levels. The present findings can be taken into consideration when culturing marine periphytic Amphora sp., Navicula sp., Cymbella sp. and Oscillatoria sp. to provide appropriate levels of protein, lipid and carbohydrate as feed supplement as well as for bioremediation in aquaculture.  相似文献   

8.
Critical thermal minima (CTmin) and lower incipient lethal temperature (LILT) were determined for Penaeus semisulcatus juveniles at combinations of four acclimation temperatures (18, 22, 26 and 30 °C) and four salinity levels (20, 25, 30 and 35 ppt). While the CTmin and LILT of shrimps were not affected significantly by salinity ( P >0.05), a direct relationship was determined between the thermal minima values (CTmin, LILT) and the acclimation temperature ( P <0.05). The acclimation response ratio for the juveniles of P. semisulcatus had an interval of 0.18–0.32 in the current study.  相似文献   

9.
Interest in the development of aquaculture of the tropical spiny lobster, Panulirus ornatus, has increased markedly over the past 10 yr because of strong market demand and high prices. In Australia, economic conditions will necessitate that a semi‐intensive approach be taken, possibly involving managed environmental conditions. Identification of optimal temperature and salinity levels will be necessary, and therefore two experiments were performed to examine these two parameters. Juvenile lobsters were grown in tanks at five temperatures (19, 22, 25, 28 and 31 C). Growth was significantly affected by temperature (P < 0.01), and maximal growth occurred at 25–31 C. Examination of the temperature effect on molt increment and intermolt period indicated that 27 C was the optimal temperature, at which molt increment was greatest and intermolt period the least. Temperature also had a significant (P < 0.01) positive effect on apparent feed intake (AFI). Juvenile lobsters were also exposed to four different salinities (20, 25, 30 and 35 ppt) over a period of 91 d. Significant differences (P < 0.01) were apparent for both survival and growth. Lowest survival occurred at 35 ppt which may be attributable to higher cannibalism at that salinity. Growth was highest at 35 ppt and progressively less at lower salinities. Although full marine salinity (35 ppt) will generate best performance of P. ornatus, its capacity to tolerate reduced salinity will provide greater opportunity to develop commercial aquaculture.  相似文献   

10.
ABSTRACT:   The growth promoting effect of carp Cyprinus carpio serum was investigated in a medium for goldfish Carassius auratus cell culture. The cell growth rate was decreased in the L-15 medium containing carp serum free from low molecular weight (LMW) fraction of less than 10 000. The addition of this fraction to the medium recovered the original growth rate, whereas the fraction itself did not enhance cell growth. Similar experiments were carried out with carp serum lipoprotein and albumin-like protein fractions. The high density lipoprotein (HDL) fraction containing apolipoprotein (apo) A-I and apoA-II enhanced cell growth at 20°C and 35°C when added with the above-mentioned LMW fraction. A good proliferation was observed at both 20°C and 35°C with the HDL fraction at 0.58 mg/mL. Carp albumin-like protein fraction, mainly containing a 71 kDa-component, also enhanced goldfish cell growth with the LMW fraction at the two temperatures. These results suggest that HDL and albumin-like proteins play an important role in the goldfish cell growth cooperatively with LMW substances contained in carp serum.  相似文献   

11.
The combined effects of temperature and diet on the growth and biochemical composition of juveniles of the pearl oyster Pinctada mazatlanica at the hatchery were investigated. Specimens were subjected to a combination of four temperatures (20, 23, 26 and 29 °C) and five microalgal diets ( Isochrysis galbana alone, I. galbana + Pavlova salina, I. galbana + Chaetoceros muelleri, C. muelleri + P. salina and I. galbana + P. salina + C. muelleri ). An increase in shell height occurred in a linear pattern, while wet weight gain fitted a power law. Temperature, more than diet, exerted a stronger influence on the growth and condition of the specimens. The combination of 29 °C with P. salina+C. muelleri led to the fastest growth in shell height, while the combination of 29 °C with I. galbana + C. muelleri led to the highest wet and dry weight biomass. In contrast, specimens grew significantly less in shell height and wet weight at 20 °C, regardless of the diet. At all temperatures, the monoalgal diet of I. galbana led to the slowest growth of specimens, but in turn favoured the highest levels of protein, carbohydrate and lipid reserves as a possible strategy to store more energy reserves under stressful events.  相似文献   

12.
SUMMARY: Effects of temperature, irradiation, salinity and inorganic nitrogen concentration on two cultured strains of zooxanthellae isolated from the corals Pocillopora damicornis (strain P) and Montipora verrucosa (strain M) were studied. Each strain showed different growth responses in terms of temperature and light intensity. A maximum growth rate of strain P, 1.2 per day, was observed at 32°C under all light intensities examined (5–40 μEm−2s−1). However, its photosystem 2 activity (FRI) was higher at 28°C than at 32°C under most light intensities. In contrast, the growth rate of strain M was affected more by light intensity and was almost invariably affected at all temperatures examined (24–36°C). Both algal strains had a comparable growth rate and FRI at salinities from 20 to 35 PSU under moderate temperature and irradiant conditions. High temperature and low irradiation reduced the algal tolerance against low salinity. The gross photosynthesis per cell was not affected by the ammonium enrichment more than 5 μM per day although the cellular chlorophyll a content and cell density increased in proportion with the ammonium enrichment up to 20 μM per day. A potential response of zooxanthellae to the multiple environmental stresses was shown from these results.  相似文献   

13.
ABSTRACT:   The optimal water temperature in seed germination and the upper critical water temperature in seedling growth were determined for Zostera marina collected from Ise Bay, Japan. The relationship between the seed germination rates and seed storage period (0, 30 and 60 days at 0°C) was also examined. The optimal water temperature for seed germination was in the range from 10 to 15°C regardless of the storage periods, in which germination rates ranged from 35 to 57%. Seedlings grown from seed up to 10 cm in total length were cultured for 1 week under various water temperatures to measure their relative growth rates. The optimal water temperature in growth was in the range from 20 to 25°C; relative growth rates ranged from 2.0 to 2.6%. Seedlings could survive up to a water temperature of 28°C, but most seedlings withered at 29 or 30°C. The optimal water temperatures for seed germination and seedling growth were related to the seasonal changes of water temperature at the sampling site. Although seedlings were rarely observed in the field in summer, they can grow at temperatures as high as 28°C. Therefore, Z. marina may extend its distribution as far as where the summer water temperature is lower than 28°C.  相似文献   

14.
We report the effect of salinity and temperature on the viability of stored culture-based subitaneous eggs of the calanoid copepod Acartia tonsa for use of copepods in fish larvae culture. Quiescence induction was recorded at 17 and 25 °C, in salinities from 0 to 30. Quiescence was strongly induced at 0 salinity and partially at 5 in both temperatures. Eggs incubated at 0 salinity for up to 12 days at both temperatures showed a decline in the fraction able to be induced into quiescence by abrupt salinity changes. The hatching success of eggs that were able to enter quiescence stabilized after a 1-day incubation and remained ∼25% viable for 12 days in 17 °C. On the contrary, the 25 °C trial showed a gradual decline in viability until stabilizing ∼10% at day 7 and onwards. Longterm 17 °C incubation for 35 days showed that eggs remained quiescent with a viability of ∼14%. Hence, we recommend salinity storage of A. tonsa subitaneous eggs as a relevant shortterm technique, and a suitable alternative to the recently proposed cold storage of eggs when eggs are to be shipped from the copepod producer to a given fish larvae hatchery.  相似文献   

15.
The combined effects of temperature and salinity on larval survival and development of the mud crab, Scylla serrata, were investigated in the laboratory. Newly hatched larvae were reared under 20 °C temperature and salinity combinations (i.e. combinations of four temperatures 25, 28, 31, 34 °C with five salinities 15, 20, 25, 30, 35 g L−1). The results showed that temperature and salinity as well as the interaction of the two parameters significantly affected the survival of zoeal larvae. Salinity at 15 g L−1 resulted in no larval survival to the first crab stage, suggesting that the lower salinity tolerance limit for mud crab larvae lies somewhere between salinity 15 and 20 g L−1. However, within the salinity range of 20–35 g L−1, no significant effects on survival of zoeal larvae were detected (P>0.05). The combined effects of temperature and salinity on larval survival were also evident as at low salinities, both high and low temperature led to mass mortality of newly hatched larvae (e.g. 34 °C/15 g L−1, 34 °C/20 g L−1 and 25 °C/15 g L−1 combinations). In contrast, the low temperature and high salinity combination of 25 °C/35 g L−1 resulted in one of the highest survival to the megalopal stage. It was also shown that at optimal 28 °C, larvae could withstand broader salinity conditions. Temperature, salinity and their interaction also significantly affected larval development. At 34 °C, the mean larval development time to megalopa under different salinity conditions ranged from 13.5 to 18.5 days. It increased to between 20.6 and 22.6 days at 25 °C. The effects of salinity on larval development were demonstrated by the fact that for all the temperatures tested, the fastest mean development to megalopa was always recorded at the salinity of 25 g L−1. However, a different trend of salinity effects was shown for megalopae as their duration consistently increased with an increase in salinity from 20 to 35 g L−1. In summary, S. serrata larvae tolerate a broad range of salinity and temperature conditions. Rearing temperature 25–30 °C and salinity 20–35 g L−1 generally result in reasonable survival. However, from an aquaculture point of view, a higher temperature range of 28–30 °C and a salinity range of 20–30 g L−1 are recommended as it shortens the culture cycle.  相似文献   

16.
TOMOYUKI  HIGUCHI  TAKAO  OJIMA  KIYOYOSHI  NISHITA 《Fisheries Science》2002,68(5):1145-1150
Heat-induced structural changes and aggregation properties of walleye pollack myosin, light meromyosin (LMM) and heavy meromyosin (HMM) were investigated. According to the circular dichroism (CD) measurement, the α-helix content of the pollack myosin and LMM were estimated to be 72% and 90% at 5°C but decreased to 22% and 21% by increasing the temperature to 60°C with two transitions at 35°C and 50°C, respectively. In contrast, that of HMM decreased gradually from 37% to 33% by increasing the temperature from 5°C to 40°C, and decreased steeply to 20% above 50°C. These results indicate that the decrease in the α-helix content in the myosin molecule upon heating was attributable mainly to the decrease in the α-helix content in the LMM region. In contrast, 1-anilinonaphthalene-8-sulfonate (ANS) fluorescence and light scattering intensity of both myosin and HMM were remarkably increased above 25°C and 35°C, respectively, while those of LMM showed only a slight change even above 60°C. Although LMM alone formed no aggregates detectable by the light scattering measurement, it formed coprecipitates with myosin but not with HMM upon heating at 40°C for 10 min. These facts suggest that LMM bind to the LMM region of the myosin. Further, it was found that myosin gel formed in a test tube by the same heating conditions was significantly weakened by coexistence of LMM. These results suggest that the association of the LMM region of myosin molecules is essential for the heat-induced gelation of myosin.  相似文献   

17.
Abstract. Trophonts of Cryptocaryon irritans Brown from infected three-spot damselfish, Dascyllus trimaculatus Ruppell, were kept at temperatures ranging from 7 to 37°C to observe encystment and development of the tomites. At 30, 25 and 20°C, the percentage of trophonts that had encysted in 16 h were 70, 77 and 64% respectively; at 37°C, 44% encysted and at 7°C only 10% had encysted.
The optimum temperature for excystment was 30°C; 50% excysted in 5 days and 100% in 7 days. At 25°C, 60% of the tomites started to excyst on the eighth day, and 70% on the ninth day. At 20°C, 10% started to excyst on the ninth day, reaching 40% on the tenth day. No excystment occurred at 37 and 7°C.
Newly encysted tomonts were placed in various dilutions of sea water (31 %0) and kept at temperatures ranging from 7 to 37°C. Low salinities, i.e. 16%0 and lower caused tomonts to rupture. At 37, 20 and 7°C, 35% of the tomonts started to rupture immediately in 50% sea water, while at 30 and 25 C, 30% of the tomonts ruptured in 25% seawater. However, none of the cysts developed normally at these dilutions. The percentage rupturing increased with decreasing salinity.  相似文献   

18.
This study was conducted to find the optimum level of dietary protein and lipid that could produce the highest growth, best feed utilization, and body composition of African catfish, Clarias gariepinus (9.5–10.3 g). Nine diets (three protein levels × three lipid levels) containing 25, 30, or 35% crude protein (CP) with 6, 9, and 12% lipids were formulated. Fish were fed one of the tested diets at the rate of 5% of body weight for the first 8 wk and 3% for the rest of the study. Diets were offered 6 d a week, twice a day (900 and 1400 h) for 13 wk. Fish growth increased significantly with increasing either protein or lipid levels, and the maximum growth was obtained in fish fed diets containing 30% CP with 12% lipid or 35% CP with 9% lipid. The lowest fish growth was obtained at 25% CP with 6% lipid. The optimum feed intake, feed conversion ratio, energy utilization, protein efficiency ratio, and protein growth rate were also recognized in fish fed the above diets. No significant differences in moisture and ash contents in fish fed diets containing different protein and lipid levels were recorded. The protein and lipid contents in the fish body tended to increase with increasing protein and lipid levels in diets. However, the higher protein contents were obtained in fish fed diets containing 35% CP with 6 or 9% lipid, while the lowest ones were obtained at 25% CP with 6 or 9% lipid. The higher lipid contents were obtained at 30 or 35% CP with 12% lipid, while the lowest ones were obtained at 25 or 35% CP with 6% lipid. The present study indicates that the increase of dietary lipid level has a protein-sparing effect, and the diet containing 30% CP with 12% lipid would be suitable for the optimum growth and effective protein utilization of fingerling African catfish.  相似文献   

19.
ABSTRACT:   Tropical minute rotifer strains (SS-type) induce mixis at 30–35°C but sexual reproduction and resting egg formation do not proceed well due to rapid environmental change. The present study examined the effect of temperature regulation on rotifer Brachionus rotundiformis (Langkawi strain, SS-type) resting egg formation in small (500 mL in culture volume)- and large-scale (500 L in culture volume) experiments. Rotifers were cultured at 30°C in 15–17 p.p.t. seawater with an initial density of 1 individual (ind.)/mL. After 4 days, when cultures were in exponential growth stage with active mixis induction, the culture temperature of the experimental rotifers was changed to 25°C. Control rotifers were cultured at 30°C throughout the experiment. Fresh or frozen Nannochloropsis oculata and condensed freshwater Chlorella vulgaris were used as the rotifer diets in the small- and large-scale experiments, respectively. Significantly higher resting egg production was observed with the experimental rotifers (30→ 25°C) versus the control rotifers. In the large-scale trial, experimental rotifers produced 2.6 × 106 resting eggs during a 9-day experiment, which was 1.6-fold more than the control rotifers. Moreover, the efficiency of resting egg formation was found to increase by a factor of 1.8. The present study indicates that decreasing culture temperature from 30 to 25°C after active mixis increased resting egg formation in B. rotundiformis (SS-type).  相似文献   

20.
This study aimed at evaluating the ploidy effects on growth performances of Chinese shrimp ( Fenneropenaeus chinensis Osbeck, 1765) reared in different salinities under laboratory conditions. In the acute salinity experiment, there was no difference ( P >0.05) in tolerance observed in triploid and diploid shrimp due to abrupt salinity changes. The lethal salinity for 50% of the individuals in 96 h at 23–25 °C was about 2 g L−1 in both triploids and diploids. While for the chronic salinity experiment, statistical analyses confirmed that the differences in growth performances including the specific growth rate (SGR), the feeding rate (FR), feed conversion efficiency (FCE) and intermoult period (IP) between triploid and diploid were related to salinity. Diploid shrimp reared in 20 g L−1 exhibited highest SGR ( P <0.05), while triploids performed well in 20 and 30 g L−1 salinities ( P <0.05). Based on the survival and growth data, the optimal salinity for the culture of diploid F. chinensis should be 20 g L−1 and for triploids it should be between 20 and 30 g L−1.  相似文献   

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