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1.
The metabolic enzyme activities were determined in larvae of red drum, Sciaenops ocellatus, and lane snapper, Lutjanus synagris, to determine the effect of temperature and nutrition on metabolic enzyme activities and to evaluate if metabolic enzyme activities are useful in assessing the feeding condition of larval fish. During experiments conducted during the spring of 1990, lactate dehydrogenase (LDH) activities in both red drum and lane snapper were approximately an order of magnitude lower than values typical for adult fish; LDH and citrate synthase (CS) activities increased during early developmental stages, but nutritional effects were apparent. Clear differences (up to 4-fold) between well-fed and starving fish were evident in both LDH and CS activity in red drum. Differences between well-fed and poorly fed larvae were evident until 9 d after hatching. Lane snapper larvae reared at a 25°C had significantly lower LDH activities than larvae reared at 28°C.  相似文献   

2.
Otoliths have frequently been used to reconstruct growth histories in larval, juvenile and adult fish. However, there is growing evidence that otolith growth is directly determined by metabolic intensity and, consequently, only indirectly related to somatic growth. By performing measurements of oxygen consumption rate and other early life-history traits on individual eggs of zebrafish (Danio rerio), we found that oxygen consumption explained residual variance in otolith size that is not accounted for by egg size. Total oxygen consumption during the embryonic stage explained 34% of the variance in sagitta size at hatch, whereas larval size at hatch (as a proxy for growth during the embryonic period) was not significantly correlated with sagitta size. This strongly suggests that otolith growth is directly related to metabolic rate, and yields a mechanism that may explain recent observations of a link between otolith size at hatch and viability in larval fish.  相似文献   

3.
Sticklebacks (Gasterosteus aculeatus) from a brackish water and a freshwater population were compared immediately after removal from their habitat and after being maintained in the laboratory. Glutamate dehydrogenase activities in the liver and both lactate dehydrogenase and aspartate aminotransferase activities in the axial muscle were higher in the brackish water sticklebacks than in the freshwater specimens. Liver glutamate dehydrogenase activities were higher in males than in females, whereas lactate dehydrogenase activities were distinctly higher in females. A significant positive correlation was found between size and both aspartate aminotransferase and lactate dehydrogenase. The population-specific activities of muscle enzymes are interpreted as an example of evolutionary adaptation of enzyme regulation. Received: 28 February 1997 / Accepted: 5 August 1997  相似文献   

4.
The aim of this study was to estimate the growth rate of saithe, Pollachius virens L., in wild populations collected from around the Beryl Alpha oil platform in October 1988 and from Loch Ewe on the west coast of Scotland in August 1989, by comparing the concentrations of various growth-rate indicators in the white muscle with those of laboratory-maintained individuals of known growth rates. There were significant correlations between the individual growth rates of laboratory-maintained saithe and concentrations of white muscle RNA expressed as g RNA mg-1 protein, mg RNA mg-1 DNA and as mg RNA g-1 muscle. Growth rate was also correlated with the activities of the enzymes citrate synthase, cytochrome oxidase and lactate dehydrogenase. RNA concentrations decreased with increasing body size, and weight-corrected estimates of RNA concentrations for a standard-sized individual were determined from the scaling relationships. RNA concentrations expressed in three different ways gave similar estimates of the growth rate for two samples of wild saithe, one from around an oil platform and the other from the west coast of Scotland. RNA concentrations were correlated with aerobic enzyme levels in oil-platform fish, although the growth rate estimates of the same wild fish were lower when expressed as a function of aerobic enzyme levels than when expressed as a function of lactate dehydrogenase concentration. It is concluded that the capacity for protein synthesis of white muscle expressed as RNA concentrations in relation to wet or dry weight may be used as an estimate of instantaneous growth rate and that additional confidence in such estimates may be gained from measurement of the levels of aerobic enzymes.  相似文献   

5.
The energetics of feeding has been investigated in demersal fish with similar sedentary lifestyles from the Antarctic (Notothenia neglecta Nybelin), North Sea (Myoxocephalus scorpius L.) and Indian Ocean (Cirrhitichys bleekeri Bleeker). In general, the metabolic rates of fasting individuals were positively correlated with adaptation temperature: values for a standard 100 g fish (mg O2/h) were 3.3 for N. neglecta at around 0 °C, 2.7 for winter-acclimatized M. scorpius at 5 °C, 4.3 for summer-acclimatized M. scorpius at 15 °C, and 7.0 for C. bleekeri at 25 °C. In all species, following a single satiating meal, oxygen consumption increased to a peak of 2 to 3.5 times the fasting values. Maximum rates of oxygen consumption after feeding were several-fold higher in the warm-than in the cold-water species. After controlling for the effects of body mass and energy intake by analysis of covariance, the duration of the increase in metabolic rate, referred to as specific dynamic action (SDA), was found to be 3 to 4 times shorter in the warm- than in the cold-water fish, ranging from 57 h in C. bleekeri to 208 h in N. neglecta. In contrast, the SDA was not significantly different in the various species, corresponding to 15 to 23% of the energy ingested. Seasonal influences on metabolism and feeding were also studied in N. neglecta acclimated to simulated winter (-1.0 to-0.5 °C; 3 h light:21 h dark) or summer (0 to 0.9 °C; 21 h light:3 h dark) conditions. The metabolic rates of fasting and fed individuals, and the characteristics of the SDA were found to be independent of acclimation conditions. This suggests that N. neglecta is capable of processing food at similar rates throughout the year. Energy stores and enzyme activities were measured in the swimming muscles and liver of fish fed ad libitum. Summer-acclimated fish had higher concentrations of liver triglyceride stores and elevated activities of some enzymes of intermediary metabolism relative to winter-acclimated fish. The observed changes in intermdiary metabolism are probably related to annual cycles of growth and reproduction. It is suggested that the low aerobic scope for physiological performance in Antarctic fish may necessitate the seasonal switching of energy allocation between growth and reproduction.  相似文献   

6.
The influence of the water-accommodated fraction of No. 2 fuel oil on aspects of larval development of Cancer irroratus (Say) has been investigated. Rates of survival, respiration, ingestion and growth were estimated for both oil-treated and untreated larvae. Larvae reared in oil-treated water exhibited lower survival to megalopa than did larvae reared in untreated water. The presence of oil also altered several aspects of larval energetics. Reductions were seen in food consumption and growth rate while the metabolic cost of maintenance increased. One overall effect that may occur as a result of lowered larval survival and growth rate would be the reduction in larval recruitment in oil-polluted areas.  相似文献   

7.
Distribution dynamics of fish larvae and juveniles in the coastal waters of the Tanshui River, Taiwan was studied fortnightly using surface horizontal tows with a larval net in daytime during the period from early April through early June 1991. Environmental factors, including water temperature, salinity, dissolved oxygen, pH, transparency and depth at sampling stations, were also monitored. A total of 10737 fish eggs and 1387 individuals, representing 43 families and 93 species, was collected during five cruises from 12 stations in the coastal waters. Most fish were estuarine-dependent marine species. Liza macrolepis, Ambassis gymnocephalus, Terapon jarbua, Mullidae and Gobiidae were the most dominant, making up 64.7% of the total catch. Early life stages, including egg, preflexion, flexion and postflexion larvae were abundant in surface samples. However, yolk-sac larvae were absent in the surface water, probably due to an ontogenetic behavioral shift as a consequence of a change in specific weight during early development. The species composition of fish larvae and juveniles was related to the microhabitats found in the coastal waters. The physico-chemical conditions, along with ontogenetic behavior, played an important role in larval fish distribution in the coastal waters.  相似文献   

8.
Plaice (Pleuronectes platessa L.) were sampled during periods of growth and starvation, from the end of the yolk-sac stage through metamorphosis, for changes in water, triglyceride, carbohydrate, total nitrogen, total carbon, and ash. The percentage of water in larvae decreased continuously during development. During post-hatching growth (up to late Stage 2) nitrogen and carbohydrate were laid down faster than triglyceride. The pattern changed during later larval development. The early deposition of protein in preference to neutral fat suggests that conversion of food during growth, without simultaneously laying down fatty energy stores, may be advantageous to pelagic marine fish larvae. During starvation the percentage of water in plaice larvae increased. Triglyceride, carbohydrate, nitrogen and carbon (as a percentage of the dry body weight) decreased during starvation, but ash increased sharply. The continuous use of nitrogen during starvation may be a catabolic adaptation to the marine environment.  相似文献   

9.
The functional status of organ systems involved into the processing of exogenous food is critical for the survival and growth of fish early life stages. The present study on laboratory-reared larval turbot, Scophthalmus maximus, provides an overview on the ontogeny of structure and functions involved in digestion, absorption and metabolism of nutrients. At start of exogenous feeding the intestine of larval turbot is anatomically differentiated, with enterocytes displaying an adult-type ultrastructure and being able to process lipids. At the microvillous border of the enterocytes, enzymes of contact digestion such as aminopeptidase are found. The ultrastructure of the exocrine pancreatic cells is fully differentiated from hatching onwards. Likewise, substantial activities of trypsin-type proteases are present. A stomach anlage exists in first-feeding larvae; however, the stomach becomes functional (appearance of gastric glands and pepsin secretion) only during metamorphosis. Liver parenchymal cells already display a functional ultrastructure during the endotrophic phase; with onset of exogenous feeding they develop pronounced diet-related changes of their energy stores. Larval respiration is not executed by the gills since respiratory surface of these structures develops only towards metamorphosis. The energy generation of larval muscle tissue depends on aerobic metabolism, whereas glycolytic activities start to increase at metamorphosis. In conclusion, two important patterns can be recognized in the development of turbot larvae: (1) The structure/function is differentiated at hatching or at the onset of exogenous feeding (afterwards it experiences mainly quantitative but not qualitative growth, i.e., intestine, exocrine pancreas, liver); or (2) the structure/function is absent in larvae and develops only during metamorphosis (i.e., gills, glycolytic muscle metabolism, stomach).  相似文献   

10.
Most animals will reduce foraging activity in the presence of a predatory threat. However, little is known about the onset of this decision-making ability during the early life stages of fishes, and how the trade-off between foraging and predator-avoidance may be affected by changes in metabolic demand during ontogeny. To examine these issues, the foraging behaviour of larval shorthorn sculpin Myoxocephalus scorpius was monitored during visual exposure to a predatory threat (juvenile Atlantic cod, Gadus morhua) throughout development at 3°C (March–April, 2004). Larvae did not respond to predatory exposure during the first week post-hatch, but thereafter showed drastic reductions in foraging activity when exposed to predators. During early development, the mass-specific routine metabolism of shorthorn sculpin larvae displayed a triphasic ontogeny and peaked during metamorphosis. This high mass-specific metabolic demand could make reduced foraging under predation threat very costly during this stage of development. To further investigate this possibility, additional experiments were performed (March–April, 2005) where larvae were reared with visual exposure to predators for 6 h day−1 during the feeding period. At 7-week post-hatch, larvae exposed to predators were smaller (wet mass and SL), showed decreased levels of whole-body lipids and certain fatty acids, and experienced higher rates of mortality as compared to control larvae. In environments where abundant predators cause larval fish to reduce their foraging rate, growth and survival of larvae may be negatively affected. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

11.
The great barracuda (Sphyraena barracuda) is a widespread, ecologically and socioeconomically important coastal fish, yet very little is known about its larvae. We examined spawning and larval ecology of Western Atlantic sphyraenids using monthly ichthyoplankton samples collected over 2 years along a transect spanning the east–west axis of the Straits of Florida (SOF). Samples were dominated by the great barracuda (92.8%) and sennets (Sphyraena borealis and Sphyraena picudilla; 6.6%). While larval sennets and S. barracuda displayed similar vertical distributions (majority in upper 25 m), horizontal and temporal patterns of abundance suggested a spatial and temporal species replacement between larval S. barracuda and sennets that tracks adult ecology. The diet of both taxa consisted largely of copepods, with inclusion of fish larvae at 8 mm SL, and in S. barracuda alone, a switch in the wet season to exclusive piscivory by 12 mm SL (18 days post-hatch). A lack of piscivory in S. barracuda larvae captured in the dry season corresponded to slower larval growth than in the wet season. Larval growth was also related to size-at-hatch and larval age such that larvae that were larger at hatch or larger (older) at capture grew faster at earlier ages, suggesting faster larval growth, and indirectly larger hatch size, conveys a survival advantage. Unlike larval growth, instantaneous mortality rate did not differ with season, and no lunar cyclic patterns in spawning output were identified. Our results provide insight into the pelagic phase of sphyraenids and highlight the importance of both diet and hatch size to the growth and survival of fish larvae in low latitude oceanic environments.  相似文献   

12.
The activities of 18 enzymes were measured in gill, hepatopancreas and muscle tissue of the deep-water crabsChaceon fenneri andC. quinquedens and the shallow-water crabCallinectes sapidus collected from the Gulf of Mexico in January 1989. The activities of catabolic enzymes were correlated in general with the known metabolic rates of the three species. Activities were much higher inC. sapidus than inChaceon fenneri andC. quinquedens. In some cases,C. quinquedens had higher activities thanC. fenneri. The activities of enzymes of amino acid metabolism (glutamate dehydrogenase and alanine aminotransferase) were higher inC. quinquedens, which had high hemolymph [ammonia] and ammonia excretion rates. The activity of lactate dehydrogenase (LDH) ofC. fenneri andC. quinquedens were correlated with the two species' abilities to withstand hypoxia. The more hypoxiatolerant species,C. quinquedens, had higher activity of LDH in its muscles than didC. fenneri.  相似文献   

13.
Summary 1. A survey of the species distribution, discharge characteristics, ecology and behaviour of South American Gymnotiforme electric fish was carried out during two field trips to sites in the vicinity of Kourou, French Guiana, in 1983 and 1985. 2. Measurements of water conditions, collected over a twelve month period, highlight the strong ecological pressure on species exploiting the rapidly fluctuating and often temporary coastal streams. Adaptation of the reproductive cycle to the rainy seasons is particularly marked and the possible zeitgebers are considered. Given the almost invariant water conductivity, its suggested use as an environmental trigger is rejected in favour of acoustic or mechanical cues. 3. The two main study areas were inhabited principally by pulse gymnotoids of the genera Gymnotus and Hypopomus. A new Hypopomus species was discovered as well as specimens of G. pantherinus, previously undescribed in French Guiana. Larvae of H. beevei were found prior to the start of the 1985 rainy season. Developmental data for this species are presented which support the view that, as in other weakly electric gymnotoids, a primitive larval electric organ probably precedes the adult structure. The larval discharge also strongly resembles that of the adult electric eel, lending weight to published theories of an Electrophorus-like ancestor to the wekly electric fish. 4. The predatory behaviour of the strongly electric eel was recorded in detail. The field results indicated that this species preyed on weakly electric fish whose responses to the foraging eel are also reported. The probable use of electrical cues by hunting eels was further investigated in a laboratory experiment in which predatory responses were compared in the presence of non-electric and electric live prey, and models mimicking electric prey. It is concluded that electrical cues are probably of paramount importance in the eel's normal prey capture behaviour.  相似文献   

14.
Tolerance to a changing climate regime and persistence in the natural environment depends on the limited capacity to acclimate to changing temperatures. The present study aimed to identify and characterize thermal limits of the Mediterranean fish Sparus aurata as well as the processes providing heat protection during exposure to high temperatures. Processes studied included heat shock protein expression, protein kinase activity and metabolic adjustments. Molecular responses were addressed through the expression of Hsp70 and Hsp90 and the phosphorylation of stress-activated protein kinases, p38 mitogen-activated protein kinase (p38 MAPK) and cJun-N-terminal kinases (JNKs). Thermal impacts on metabolic capacities were assessed by studying the maximum activities of citrate synthase (CS), malate dehydrogenase (MDH) and 3-hydroxyacyl CoA dehydrogenase (HOAD) as well as pyruvate kinase (PK) and lactate dehydrogenase (L-LDH). The expression of Hsp70 and hsp90 was activated when the fish were exposed to temperatures beyond 20°C. Increased phosphorylation of p38 MAPK and JNKs indicated the parallel activation of MAPK signaling cascades and the potential involvement of MAPKs in the induction of Hsp genes. Exposure to extreme temperatures beyond 24°C caused an increase in the enzymatic activity of PK and LDH indicating an enhanced glycolytic potential.  相似文献   

15.
Summary. Mountain birches are deciduous trees consisting of several clonal and partly autonomous ramets. Autumnal moth, Epirrita autumnata, is an extremely harmful pest of mountain birches that during outbreak years may cause the death of trees over large areas. During the larval development of E. autumnata, leaf characters and nutritional suitability vary considerably both temporally and spatially among and within mountain birches. Compared to variation between trees, however, the extent of within-tree variation is known for only a limited number of potentially defensive traits. Plant oxidases, polyphenoloxidases (PPOs) and peroxidases (PODs) may play an important part in dictating the suitability of a tree for plant-eating animals, including E. autumnata. In this study, we observed changes in the activities of oxidative and antioxidative enzymes along leaf development during the larval period of E. autumnata. We also estimated the relative amounts of spatial variation among and within trees. Our results show that POD activities were remarkably high during the rapid elongation growth phase of leaves but decreased with leaf maturation. Thus PODs are suggested to take part in leaf elongation growth. Time and within tree variation accounted for the most of variation in POD activities whereas there was no among tree variation. In contrast, the activities of antioxidative CATs, which act as antagonists to PODs, were low in young leaves and increased towards leaf maturation, reflecting an increase in the oxidative status of source leaves. Within tree variation accounted for the most of the variation in CAT activities. The absolute PPO activities decreased along leaf growth due to the dilution effect whereas the specific activity of PPOs, which has been shown to be defensive against E. autumnata larvae, did not vary temporally that might reflect the importance of these enzymes in the defence of birches. Acidic PPOs showed marked within- and among-tree variation, which may impact herbivores performance on certain genotypes and increase larval mobility within the tree canopy.  相似文献   

16.
In the context of future scenarios of anthropogenic CO2 accumulation in marine surface waters, the present study addresses the effects of long-term hypercapnia on a Mediterranean fish, Sparus aurata. By equilibration with elevated CO2 levels seawater pH was lowered to a value of 7.3, close to the maximum pH drop expected in marine surface waters from atmospheric CO2 accumulation. Intra- and extracellular acid–base parameters as well as changes in enzyme profiles were studied in red and white muscles and the heart under both normocapnia and hypercapnia. The activities of pyruvate kinase (PK), lactate dehydrogenase (L-LDH), citrate synthase (CS), malate dehydrogenase and and 3-hydroxyacyl CoA dehydrogenase (HOAD) reflect the pathways and capacity of oxidative processes in metabolism. Long-term hypercapnia caused a transient reduction in blood plasma pH (pHe) as well as in intracellular pH (pHi). Compensation of the acidosis occurred through increased plasma and cellular bicarbonate levels. Changes in enzymatic activities, especially the increase in the activity of L-LDH, paralleled by a drop in CS activity in white and red muscles reflect a shift from aerobic to anaerobic pathways of substrate oxidation during long-term acclimation under hypercapnia. The present results suggest that moderate environmental hypercapnia changes the metabolic profile in tissues of S. aurata. Consequences for slow processes like growth and reproduction potential as well as potential harm at population, species and ecosystem levels require further investigation.  相似文献   

17.
Protein, total lipid, and the activities of the enzymes alkaline phosphatase (AP) and glutamic oxaloacetic transaminase (GOT) were measured daily during larval development of the xanthid crab Rhithropanopeus harrisii (Gould). Percent increase in fresh weight was greatest on the first day after each molt. Protein and total lipid per larva increased during the second, third, and fourth zoeal stages, with the most marked increase during the third. When calculated as percent fresh weight, marked accumulation of both protein and total lipid occurred during the third zoeal stage. GOT activity remained stable during the third zoeal stage, but increased significantly during the fourth zoeal stage. AP showed a 4-day cycle of activity apparently related to the molt cycle. It is suggested that increased protein and total lipid content during the third zoeal stage indicate nutritional requirements prior to metamorphosis. Biochemical change may be a more relevant indicator of growth during larval development than either size increase or molt frequency when assessing the value of various diets in the culture of crabs.  相似文献   

18.
R. T. Kneib 《Marine Biology》1981,63(2):213-215
The conversion efficiency (gross growth efficiency) of larval Fundulus heteroclitus fed newly hatched Artemia sp. nauplii was recently reported as the lowest observed (0.69 to 1.11%) for a fish. A recalculation of the efficiencies, based on data from Radtke and Dean, showed that the original determinations were in error by two orders of magnitude. The recalculated values (69.0 to 114.4%), however, are impossibly large and probably result from measurement error in the determination of the weight of a single prey individual (nauplius). Using a nauplius weight estimate from the literature, the conversion efficiencies were again recalculated. The new efficiencies (25 to 41%) agree with those reported for other fish species. The values are still higher than those reported elsewhere for adult F. heteroclitus, but this is consistent with the generalization that conversion efficiency decreases with age.Contribution No. 422 of the University of Georgia Marine Institute  相似文献   

19.
硫化物胁迫对日本沼虾呼吸代谢和能量代谢酶的影响   总被引:2,自引:0,他引:2  
研究了硫化物暴露后日本沼虾细胞色素氧化酶(CCO)、琥珀酸脱氢酶(SDH)、延胡索酸还原酶(FRD)和乳酸脱氢酶(LDH)4种呼吸代谢酶及能量代谢酶-精氨酸激酶(AK)活性的变化规律.将日本沼虾暴露于0.6 mg·L~(-1)、2mg·L~(-1)的2个硫化物质量浓度组和不含硫化物的对照组水体中,暴露后0、2、12、24、48 h和解除暴露后48 h取肝胰腺和肌肉组织进行酶活性分析.结果显示:肝胰腺和肌肉组织SDH和CCO活性随硫化物质量浓度升高或暴露时间延长而显著降低(P<0.05).FRD、LDH和AK活性随硫化物质量浓度升高或暴露时间延长而显著升高(P<0.05).解除硫化物暴露后48 h,各质量浓度组酶活性与对照组无显著差异.上述酶活性还存在组织差异,肝胰腺呼吸代谢酶活性高于肌肉中相应酶活性,而AK活性与此相反.结果表明,硫化物胁迫导致日本沼虾有氧呼吸代谢减弱,无氧呼吸代谢增强,并动用其能量贮存物质磷酸精氨酸,产生更多ATP以适应外界不良环境.  相似文献   

20.
微塑料是水环境中一种含量丰富的污染物。但关于其对幼鱼的影响情况知之甚少。我们考察了塑料微珠的密度增大对黑头软口鲦(Pimephales promelas)幼鱼觅食和生长的影响。我们发现微塑料对幼鱼摄食幼虫卤虫无节幼体(Artemia nauplii)的摄食量影响很小,对30天体长也基本无影响。 精选自Timothy David Malinich, Nathan Chou, Maria S. Sepúlveda, Tomas O. H??k. No evidence of microplastic impacts on consumption or growth of larval Pimephales promelas. Environmental Toxicology and Chemistry,2018,37:2912-2918.
详情请见 https://doi.org/10.1002/etc.4257
  相似文献   

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