首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 109 毫秒
1.
NAD+-linked isocitrate dehydrogenase was found in the brain, heart, gills, kidney, liver and muscle of trout, and in the liver and muscle of eel. A complex homogenization buffer containing 1 mM ADP, 5 mM MgSO4, 5 mM citrate and 40% glycerol is required for retrieval of significant amounts of stable enzyme. The highest activities were found in brain of trout and the lowest in white muscle of trout and eel. The enzyme was partially purified from frozen trout heart to a final activity of 0.04 M/min/mg protein, and the kinetic properties of this partially purified enzyme were studied. The enzyme requires either Mn2+ or Mg2+ for activity, higher activities being observed with Mn2+. Saturation kinetics for DL-isocitrate were sigmoidal, apparent S0·5=8.2±0.6 mM and nH=1.8±0.2, in the absence of ADP, changing to hyperbolic, apparent S0·5=1.4±0.3 mM and nH=1.0, with 1 mM ADP added. Citrate and Ca2+ were found to activate the enzyme to a small extent. NADH strongly inhibited the enzyme, I50=3.7±0.5 M. ATP was also found to be an inhibitor, I50=7.2±1.4 mM. These properties are consistent with the role of the enzyme as a major control site of the tricarboxylic acid cycle.  相似文献   

2.
This study was performed to determine compensatory growth of juvenile olive flounder fed the extruded pellet (EP) with different feeding regimes. Seven treatments with triplicates of different feeding regimes were prepared; α fish was daily fed for 6 d a week throughout 8 wk (8WF); α fish was starved for 1 wk and then fed for 3 wk twice [(1WS + 3WF) × 2]; β fish was starved for 2 wk and then fed for 6 wk (2WS + 6WF); χ fish was starved for 5 d and then fed for 9 d four times [(5DS + 9DF) × 4]; δ fish was starved for 10 d and then fed for 18 d twice [(10DS + 18DF) × 2]; δ fish was starved for 2 d, fed for 5 d, starved for 3 d, and then fed for 4 d four times [(2DS + 5DF + 3DS + 4DF) × 4]; and φ fish was starved for 4 d, fed for 10 d, starved for 6 d, and then fed for 8 d twice [(4DS + 10DF + 6DS + 8DF) × 2], respectively. Total feeding day was all same, 36 d except for control group (48 d). Weight gain of flounder in the 8WF treatment was higher than that of fish in other treatments. And weight gain of flounder in the 2WS + 6WF treatment was higher than that of fish in the (5DS + 9DF) × 4 and (4DS + 10DF + 6DS + 8DF) × 2 treatments. Feed consumption of flounder in the 8WF treatment was higher than that of fish experienced feed deprivation. Feed efficiency ratio (FER), protein efficiency ratio (PER), and protein retention (PR) were not significantly different among treatments. Chemical composition of the whole body of fish with and without liver, except for moisture content of liver, was not different among treatments. T3 level of fish in the 8WF and 2WS + 6WF treatments was higher than that of fish in the (5DS + 9DF) × 4 treatment. It can be concluded that juvenile olive flounder achieved better compensatory growth at 6‐wk refeeding after 2‐wk feed deprivation compared with that of fish with different feeding regimes. And T3 level of fish seemed to partially play an important role in achieving compensatory growth.  相似文献   

3.
Appetite, growth, and protein turnover (synthesis, growth and degradation) of liver and gills were measured in juvenile rainbow trout (Oncorhynchus mykiss) fed to satiation, and exposed for 90 days to elevated winter temperatures (+2 °C above ambient) and either low pH (5.2) in softwater or 70 M total ammonia (TAmm) in hardwater. All fish increased in weight during the experiments, but those exposed to +2°C grew significantly more than those at ambient temperature due to a stimulation of appetite. During the relatively constant temperature of the first 75 days, +2 °C caused a significant increase in the rates of protein synthesis and degradation in the liver of hardwater-acclimated fish, as a result of an increase in RNA translational efficiency (KRNA). The elevated temperature also induced an increase in gill protein synthesis in softwater-acclimated fish but in this case the underlying mechanism was an increase in Cs, the capacity for protein synthesis (RNA:protein) rather than in KRNA. The addition of 70 M TAmm had no effect on protein turnover in either liver or gills of hardwater-acclimated fish. Low pH inhibited protein growth in the liver of softwater-acclimated fish at day 90 under both temperature regimes. This inhibition was effected via a decrease in protein synthesis at control temperature but via an increase in protein degradation when the fish were exposed to both low pH and +2 °C. From these results we conclude that a simulated global warming scenario has potentially beneficial rather than detrimental effects on protein turnover and growth of freshwater fish during winter.  相似文献   

4.
The ability of diphenyl diselenide [(PhSe)2] to attenuate oxidative damage was evaluated in the liver, gills, brain, and muscle of carp (Cyprinus carpio) and silver catfish (Rhamdia quelen) experimentally exposed to fipronil (FPN). Initially, the fish were fed a diet without (PhSe)2 or a diet containing 3.0 mg/kg of (PhSe)2 for 60 days. After the 60-day period, the fish were exposed to 0.65 µg/L of FPN for 192 h. The results showed that carp exposed to FPN and not fed with (PhSe)2 exhibited acetylcholinesterase (AChE) inhibition in brain and muscle, and increased thiobarbituric acid-reactive substance (TBARS) in liver, gills, and brain. Furthermore, FPN decreased nonprotein thiols (NPSH) and δ-aminolevulinate dehydratase (δ-ALA-D) in carp liver and gills, and increased plasma glucose and protein levels. In silver catfish, FPN inhibited AChE and increased TBARS levels in muscle. In addition, glutathione S-transferase (GST) decreased in liver and muscle, and plasma glucose was increased. (PhSe)2 reversed some of these effects. It prevented the increase in TBARS levels in liver, gills, and brain in carp and in silver catfish muscle, and reversed the increase in plasma glucose levels in both species. Additionally, (PhSe)2 increased the NPSH levels in carp and silver catfish that had decreased in response to FPN exposure. However, (PhSe)2 was not effective in reversing the AChE inhibition in brain and muscle or the δ-ALA-D decrease in carp liver. Thus, (PhSe)2 protects tissues of both species of fish, mainly by preventing or counteracting the effects of FPN, on TBARS levels, antioxidants, and present anti-hyperglycemic property.  相似文献   

5.
Extracellular fluid volume (ECFV) estimates were determined in various tissues and whole body of resting, chronically cannulated rainbow trout (Oncorhynchus mykiss). Fish were infused with14C-inulin,3H-polyethylene glycol (PEG, M.W. 4000),3H-mannitol, or14C-mannitol, and values of ECFV determined from tissue: plasma water distribution ratios after 6 h or 13 h equilibration. Overall,3H-PEG provided the most conservative and reliable estimates after 13 h equilibration, with ECFV values in the order: brain < white muscle < red muscle < liver < heart < gill tissue.14C-inulin yielded generally similar values to3H-PEG at 13 h, but probably overestimated ECFV in liver.3H-mannitol and14C-mannitol spaces were similar to each other and far greater than3H-PEG or14C-inulin values in most tissues.3H-mannitol values increased significantly between 6 h and 13 h, in contrast to14C-inulin. Mannitol clearly overestimated ECFV in liver and gill, and probably also heart and whole body, but may have provided more realistic estimates in brain due to better penetration of the blood-brain barrier. The Cl–/K+ space technique overestimated ECFV in gills, but was satisfactory in white muscle. Measurements and model calculations evaluated sources of error in intracellular pH (by14C-DMO) and ion determinations. Trapped red cells in the gills have negligible influence. Errors in ECFV are much more influential in a tissue with a high ECFV (gills) than a low ECFV (white muscle).3H-PEG is the marker of choice for intracellular pH determinations. However, even when3H-PEG is used, the potential for absolute errors in intracellular ion concentrations remains high.  相似文献   

6.
A study was undertaken to investigate the effects of graded dietary levels and different types of carnitine on hybrid striped bass (Morone chrysops × M. saxatilis %) fed different levels of lipid. An incomplete factorial design was utilized in which diets containing lipid at either 5 or 10% were supplemented with l-carnitine at 0, 500, or 1000 mg kg–1 diet, dl-carnitine at 1000 mg kg–1 diet, or carnitine chloride to provide 1000 mg carnitine kg–1 diet. Juvenile hybrid striped bass (3.3 g fish–1) were stocked into individual 38-l aquaria connected as a brackish water (6), recirculating system and fed each diet in triplicate for 9 weeks.Supplementation of the diet with 1000 mg carnitine kg–1 increased muscle carnitine from 35.5 to 47.7 g g–1 tissue. Carnitine supplementation did not result in increased weight gain regardless of carnitine level or type; however, weight gain showed a significant (p<0.05) response to dietary lipid with fish fed diets containing 10% lipid growing 34% more than fish fed diets with 5% lipid. The hepatosomatic index also was unaffected by diet, but the intraperitoneal fat (IPF) ratio was significantly elevated (5.1 vs 3.2%) in fish fed diets with 10% lipid compared to those fed diets with 5% lipid. Fish fed diets containing 1000 mg carnitine kg–1 had increased IPF ratio values at 4.7% compared to 3.9% for fish fed the basal diet. Liver lipid also was responsive to dietary treatment, increasing from 6.7 to 8.8% of wet weight as dietary lipid increased from 5 to 10%. The relative quantities of triglycerides, free fatty acids and phospholipids in muscle and liver were not influenced by carnitine level, carnitine type or dietary lipid level. Supplementation of carnitine does not appear to be beneficial to hybrid striped bass based on either growth performance or body composition.  相似文献   

7.
采用静水生物测试法研究铜(Cu2+)对刀鲚(Coilia nasus)幼鱼的急性毒性并进行安全性评价。根据预实验结果, 设定0.3、0.54、0.96、1.68 和3 mg/L 5个CuSO4浓度梯度进行急性暴露实验, 以肝组织超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性为指标, 并通过观察肝、鳃组织病理变化来研究Cu2+污染对刀鲚幼鱼的毒性效应。结果表明, 刀鲚幼鱼随Cu2 + 浓度升高毒性效应逐渐增强, 24、48、72和96 h LC50分别为1.087、1.062、1.042和0.967 mg/L, 安全质量浓度为0.009 67 mg/L。刀鲚幼鱼暴露24 h之后, 各Cu2+浓度处理组(0.1, 0.2, 0.3 mg/L) CAT活性、SOD活性显著提高(P<0.05); 暴露48 h后, 各组CAT活性下降, CAT活性均低于对照组, 下降幅度与Cu2 +质量浓度呈正相关, SOD活性提高显著(P<0.05); 暴露72 h后, SOD活性有所下降, SOD活性均低于对照组(P<0.05)。1.68 mg/L和3 mg/L的Cu2+浓度对刀鲚幼鱼的鳃和肝都造成严重的损伤, 暴露在高浓度组(3 mg/L)中的刀鲚, 其鳃上皮细胞肿大变性, 鳃小片几乎全部脱落; 肝呈黄色, 超微结构发现肝细胞明显增大, 线粒体空泡化, 胞质中出现空泡和大量脂滴, 表明Cu2+可诱发刀鲚出现脂肪肝综合征。SOD、CAT活性变化以及鳃、肝结构变化都反映刀鲚幼鱼受伤害的程度, 可用作安全性风险评价的参考依据。  相似文献   

8.
The theory of non-ionic diffusion predicts that ammonia will distribute between intracellular and extracellular tissue compartments according to transmembrane pH gradients. The distribution of ammonia and14C-DMO were compared in white muscle and plasma of rainbow trout (Salmo gairdneri) at rest, and following exhaustive exercise. Under both experimental conditions, intracellular ammonia levels far exceeded those predicted by transmembrane pH gradients. Calculated equilibrium potentials for ) were very close to published resting values of membrane potential Em in fish white muscle. We conclude that NH 4 + is permeable across cell membranes and that intracellular ammonia stores are not determined by pH gradients.The term ammonia or Tamm will be used to indicate the total ammonia concentration, while NH 4 + and NH3 will refer to ammonium ion and nonionic ammonia, respectively.  相似文献   

9.
Copper is an essential element, but at high concentrations, it is toxic for living organisms. The present study investigated the responses of goldfish, Carassius auratus, to 96 h exposure to 30, 300, or 700 μg L?1 of copper II chloride (Cu2+). The content of protein carbonyls was higher in kidney (by 158%) after exposure to 700 mg L?1 copper, whereas in gills, liver, and brain, we observed lower content of protein carbonyls after exposure to copper compared with control values. Exposure to copper resulted in increased levels of lipid peroxides in gills (76%) and liver (95–110%) after exposure to 300 and 700 μg L?1 Cu2+. Low molecular mass thiols were depleted by 23–40% in liver and by 29–67% in kidney in response to copper treatment and can be used as biomarkers toxicity of copper. The activities of primary antioxidant enzymes, superoxide dismutase and catalase, were increased in liver as a result of Cu2+ exposure, whereas in kidney catalase activity was decreased. The activities of glutathione-related enzymes, glutathione peroxidase, glutathione-S-transferase, and glutathione reductase were decreased as a result of copper exposure, but glutathione reductase activity increased by 25–40% in liver. Taken together, these data show that exposure of fish to Cu2+ ions results in the development of low/high intensity oxidative stress reflected in enhanced activities of antioxidant and associated enzymes in different goldfish tissues.  相似文献   

10.
Juvenile rainbow trout (2–5 g) were chronically exposed (for 22 days) to acidified softwater (Ca2+ = 25 Eq/l, pH 5.2) in the presence or absence sublethal Al (30 g/l). Al-exposed fish (5.2/Al group) suffered 20% whole body Na+ and Cl– losses and a 30% reduction in the maximum sustainable swimming speed (Ucrit) over the initial 7 days. These disturbances were approximately 2 fold greater than those observed in the fish exposed to low pH alone (5.2/0 group). However, whole body ion levels were completely restored in the 5.2/Al fish by day 22, whereas they merely stabilized at a new reduced level in the 5.2/0 group. Increased resistance to acutely lethal Al (200 g/l at pH 5.2) was observed from day 17 onwards in the 5.2/Al fish. Despite this acclimation and recovery of whole body ions, Ucrit remained significantly lower than in the 5.2/0 group throughout. Growth on a restricted diet of 1% body wt. /day was normal in the 5.2/0 group compared with controls maintained in pH 6.5 softwater, whereas 5.2/Al fish suffered a 50% reduction in growth rate on the same diet. The 5.2/Al fish accumulated large amounts of Al on the gills, reaching an initial peak after 4 days, followed by a decline at 7 days, and a secondary rise thereafter. Therefore acclimation and recovery of whole body ionic status was not associated with a reduction in the gill Al burden. Some of the metabolic costs of acclimation to Al, namely a continued impairment of swimming speed and growth, are discussed in light of the physiological and structural changes reported to occur at the gills.  相似文献   

11.
Atlantic salmon (Salmo salar L) postsmolts weighing 150 ± 53 g were exposed to 14–15 mg l–1 TA-N (total ammonia-N) in sea water in 1 m3 tanks for 24h. Blood samples were then taken A) immediately after the fish were netted from the exposure tanks and stunned by a blow to the head; B) 2–20 min after the fish were transferred to 15 l of an anaesthetic solution of metomidate in ammonia-free sea water; or C) 2–20 min after the fish were transferred to 15 l of ammonia-free sea water. Plasma TA-N level was 18% lower in the anaesthetised fish compared to in the fish sampled directly from the exposure tanks (p 0.05), and accordingly 16% lower in the fish transferred to pure sea water although this difference was not significant (p = 0.07). Plasma glucose level was higher in the fish transferred to pure sea water than in the fish receiving the two other treatments (p 0.05), but plasma urea, osmolality, Na+, Cl–, Ca2+ or Mg2+ levels did not vary significantly between the different treatments. Plasma TA-N level increased with time in the fish in the metomidate solution (p 0.02).  相似文献   

12.
Contamination of aquatic ecosystems by metals causes various biochemical changes in aquatic organisms, and fish are recognized as indicators of environmental quality. Silver catfish were exposed to six concentrations of zinc (Zn): 1.0, 2.5, 5.0, 7.5, 10.0 and 12.5 mg/L for 96 h to determine the mean lethal concentration (LC50). The value obtained was 8.07 mg/L. In a second experiment, fish were exposed to concentrations of 1.0 or 5.0 mg/L Zn and a control for 96 h. Afterward, the tissues were collected for biochemical analysis. Lipid peroxidation, as indicated by thiobarbituric acid-reactive substance (TBARS), decreased in the liver and brain for all Zn concentrations tested, while in the gills TBARS levels increased at 1.0 mg/L and declined at 5.0 mg/L. Zn increased protein carbonyls in the muscle of silver catfish and decreased it in the other tissues. The enzyme superoxide dismutase increased in both exposed groups. However, catalase did not change. Glutathione S-transferase decreased in the liver and increased in the gills (1.0 mg/L), muscle (5.0 mg/L) and brain (1.0 and 5.0 mg/L). Nonprotein thiols changed only in brain and muscle tissue. Zn exposure inhibited acetylcholinesterase (AChE) activity in the brain at both concentrations tested, but did not change it in muscle. Exposure to Zn inhibited the activity of Na+/K+-ATPase in the gills and intestine at both concentrations tested. Our results demonstrate that Zn alters biochemical parameters in silver catfish and that some parameters such as AChE and Na+/K+-ATPase could be considered as early biomarkers of waterborne Zn toxicity.  相似文献   

13.
In order to assess the possibilities of utilizing drainage effluents (salinity range 5.0–12.5), fish culture experiments were carried out. Experiments on polyculture using cow dung (24 000 kg ha–1 y–1) as pond fertilizer were conducted at five different salinity levels (0.3–8.5). Studies have revealed that carp perform well in salinities up to 7.5 and reasonably high fish production has been obtained. Even though the ponds had a high trophic status, higher salinities ( > 7.5) appear to repress fish growth probably due to low dissolved oxygen (DO), high BOD and high NH4-N. Experiments on monoculture of common carp (Cyprinus carpio) conducted at two different salinity levels (0.3–0.9 and 6.0–7.0) using four different organic fertilizers (cow dung at 24 000 kg and 20 000 kg, poultry at 1500 kg, duck at 6000 kg and sheep/goat at 1500 kg ha–1 y–1) have revealed the highest fish growth to be in poultry-treated ponds, followed in decreasing order by duck and sheep/goat wastes. Similar trends in fish production were observed both in fresh- and salt-water ponds. However, fish production was lower in ponds having higher salinities ( > 7.5). Nevertheless, these studies indicated that inland saline waters can be utilized for fish culture. With minor modifications in the existing technology of fish culture in stagnant freshwater fish ponds, animal wastes could be used to fertilize brackishwater fish ponds.  相似文献   

14.
After adapting Atlantic halibut, Hippoglossus hippoglossus (L.), to three different levels of available dietary carbohydrate (22, 47 and 82 g kg-1), the uptake of intraperitoneally injected glucose, both labelled and unlabelled, by the liver, white muscle, plasma, gills, heart, kidney and gastrointestinal wall, as well as concentrations of glucose in plasma and glycogen in organs, were studied. Even 16 h after glucose injection, halibut showed hyperglycaemia. The response, however, was moderate when adapted to the two higher than to the lowest starch diet, indicating some adaptative capacity. A negative correlation was found between plasma glucose and liver glycogen concentrations, hepatosomatic index and liver weight. The amount of glucose restored, relative to the amount injected, demonstrated that adaptation to dietary starch had significant effects on liver glycogen levels, with the highest incorporation of labelled glucose being observed in halibut adapted to the lowest dietary starch level. The amount of labelled glucose restored was highest in liver, followed by muscle > gastrointestinal wall > plasma > gills > kidney and heart, when evaluating the amount in the total organ. An indication of which organ was the most metabolically active in glucose utilization was found by expressing the results on a concentration basis, and it decreased in order, heart > gills > intestinal wall > kidney and muscle.  相似文献   

15.
The impacts of bacterial infection on cultivated fish species, African catfish, were investigated using oxidative stress biomarkers [lipid peroxidation (LPO) and protein carbonylation] and the activities of important antioxidant/detoxifying enzymes [catalase and glutathione S-transferase (GST)]. Fish were inoculated via oral gavage with one of the following treatments: 1 × 105 CFU/ml of Escherichia coli (EC1), 2 × 105 CFU/ml of E. coli (EC2), 1 × 105 CFU/ml of Vibrio fischeri (V1), 2 × 105 CFU/ml of V. fischeri (V2), gavaged with distilled water and not gavaged. Fish were maintained in the laboratory for 7 days after the bacterial inoculation, and the levels of LPO, protein carbonylation, GST, and catalase activities were determined in the muscle, gills, and liver of fish. Fish inoculated with bacteria (either E. coli or V. fischeri) had a significant higher levels of tissue LPO, protein carbonylation, and GST activities in a tissue-specific pattern (liver > muscle > gills). This appears to be related with the levels of bacterial inoculation, with effects more pronounced in fish inoculated with either EC2 or V2. The catalase activity did not differ significantly between the inoculated and fish that were not inoculated. The results of this study indicate that bacterial inoculation could result in oxidative stress in fish, and liver has a higher rate of oxidative stress per mg tissue compared to the gills and the muscle.  相似文献   

16.
Rainbow trout (Oncorhynchus mykiss) were acclimated to 4 and 18°C and fed at rations levels which led to an equal change in mass at these temperatures during the six week acclimation. Thermal acclimation markedly modified the metabolic organization of red and white muscle. Cold-acclimated fish had activities of -hydroxyacyl CoA dehydrogenase in both red and white muscle that were twice those of warm-acclimated fish. By contrast, the activities of cytochrome oxidase were unchanged by thermal acclimation. Thus, the capacity for -oxidation of lipids is specifically enhanced in the muscle of cold-acclimated trout. In white muscle, citrate synthase and phosphofructokinase activities were also enhanced by cold acclimation (increases of 125% and 35% respectively), while cytochrome oxidase levels were unchanged. The non-parallel changes in the activities of mitochondrial enzymes strongly suggest that trout muscle mitochondria undergo qualitative reorganization during cold acclimation. The relative activities of mitochondrial enzymes suggest that mitochondria from red muscle have a threefold greater capacity to oxidize lipids than those from white muscle.  相似文献   

17.
铬对鲤嗜多染红细胞微核的诱变效应   总被引：3，自引：0，他引：3  
在实验室条件下以不同浓度Cr^6 (0．122、0．670、1．219、3．657、10．971和32．913mg／L)水体染毒鲤鱼种40d，微核试验结果表明：处理组铬浓度的提高，其嗜多染红细胞微核率相应提高。鲤暴鳝于Cr^6 3．66～32．91mg／L时，铬处理鱼微核细胞率较对照组鱼有明显差异。鱼肌肉、鳃、肝和肾组织内的Cr^6 残留量同其微核率呈正相关关系。  相似文献   

18.
The effects of trout recombinant growth hormone (rtGH) treatment (0.25 g g–1 by intraperitoneal implant) on plasma ionic regulation, extracellular acid-base status and respiration were investigated in freshwater rainbow trout and during a 4-day period after direct transfer into seawater (35 g 1–1).In freshwater, rtGH treatment resulted in a significant increase in gill (Na+, K+) ATPase activity and in standard metabolism (MO2). The latter would mainly result from a higher rate of protein synthesis. Direct transfer from freshwater to seawater induced a decrease in arterial blood pH, far more pronounced in controls than in treated fish. This effect could be regarded in both groups mainly as a metabolic acidosis resulting from extracellular ion composition changes (i.e., an increase higher in chloride than in sodium, more marked in controls than in treated fish). As the rise in PaCO2, in spite of an increase in ventilatory activity, is more significant in controls than in treated fish, it can be assumed that rtGH treatment lightened the decrease in the gas diffusing capacity of gills induced by transfer to seawater. The initial increase in MO2 in both controls and treated fish could be the consequence of an increase in energetic cost of ventilation and osmoregulation. Then, in treated fish, the persistent high level of M may indicate a stimulation of intermediary metabolism by rtGH. In addition, the absence in treated fish of an increase in plasma lactate concentration, as observed in controls, would indicate that rtGH attenuated the decrease in O2 affinity of haemoglobin foreseeable from the metabolic acidosis.This article is dedicated to Professor Claude Peyraud, whose recent death has deeply saddened us. We respectfully pay a tribute to his memory.  相似文献   

19.
Asian catfish, Clarias batrachus, were fed semi-purified basaldiets containing 0, 0.1, 0.5, 1, 3 and 5 mg biotin kg–1diet for 60 days. Fish fed the control diet (no biotin) showed(P < 0.05) higher mortality, lower weight gain, specificgrowth rate (SGR), feed efficiency ratio (FER) and protein efficiencyratio (PER) than in fish fed diets supplemented with biotin. The highestweight gain, SGR, FER and PER were noticed in fish fed 1 mg biotinkg–1, followed by 0.5, 5, 3 and 0.1 mg biotinkg–1, except for PER (followed by 0.5, 5, 0.1 and 3 mgbiotin kg–1). Quadratic analysis showed that the optimumdietary biotin requirements for maximal weight gain, PER and PER were2.49, 2.54 and 2.52 mg kg–1, respectively. Liver biotinconcentrations were influenced by levels of biotin in the diet.Concentration of liver biotin increased as level of dietarysupplementation increased and no biotin was detected in the liver of thecontrol fish. Liver pyruvate carboxylase and acetyl CoA carboxylaseactivities were higher in fish fed biotin-supplemented diets than incontrols. Biotin concentrations, pyruvate carboxylase and acetyl CoAcarboxylase activities in liver associated with normal growth rangedfrom 10.59 to 10.66 g g–1, 147.97 to 148.18 units mgprotein–1 and 12.76 to 12.78 units mg protein–1, respectively. Biotin deficiency symptoms such as anorexia, darkskin colour and convulsions were observed in fish fed the control diet.The optimum dietary biotin requirement for maximal growth of C.batrachus is about 2.49 mg kg–1 diet.  相似文献   

20.
Cytosolic extracts of liver and brain showed specific, saturable binding with [3H]dexamethasone: Scatchard plots were linear. Cortisol and 11-deoxycortisol acted as competitors, whilst 17,20-dihydroxy-4-pregnen-3-one was relatively much less effective. There was a four-fold range of differences in specific binding capacity between dissected brain regions, the order being telencephalon > hypothalamus > rhombencephalon > optic tectum (thalamus + tegmentum + torus semicircularis) when Nmax was calculated in terms of DNA content. There was no evidence for any binding of [3;H]dexamethasone with membrane fractions.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号