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 581 毫秒
1.
The nutritional effect of vitamin E in dietsfor Litopenaeus vannamei postlarve (PL19)was investigated. Four formulated diets withdifferent combinations of -tocopherylacetate (-TA), ascorbic acid (AA) andhighly unsaturated fatty acids (HUFA) weretested, using four replicates.No significant differences in survival wereobserved among treatments after 34 days offeeding. However, shrimp fed with a dietcontaining 2% fish oil (low n-3 HUFA content),200 mg.kg–1 -TA and100 mg.kg–1 AA (diet H/E/C) showedsignificantly better growth than those fed adiet supplemented with 5% fish oil (high n-3HUFA content), 200 mg.kg–1 -TA and100 mg.kg–1 AA (diet H+/E/C). Shrimp fedwith a diet containing 5% fish oil,900 mg.kg–1 -TA and100 mg.kg–1 AA (diet H+/E+/C) showed a significantly higher tissue level of n-6 PUFAthan postlarvae fed diet H+/E/C. No definiteconclusion could be drawn about a possibleinteraction between -TA and AA, since acomparison of the diet containing 5% fish oil,200 mg.kg–1 -TA and700 mg.kg–1 AA (H+/E+/C+) and the dietH+/E/C did not show any significant differencesin any of the measured parameters. Theantioxidative status of the shrimp tissue(measured by means of the thiobarbituric acid(TBA) assay and expressed as nM malonaldehyde(MA) per gramme dry weight) was equal for alltreatments. Nevertheless, there was a slightlylower MA value with the diet H+/E/C+,indicating that AA may be an effectiveantioxidant in the aqueous phase and at thewater/lipid interface of the tissue. The tissuelevels of -T and AA were highlydependent on the amounts in diets and nocorrelation between -T and AAincorporation could be observed.  相似文献   

2.
Atlantic salmon (Salmo salar L.) parr were fed for one month on fish meal based diets supplemented with Cd (0, 0.7, or 204 mg Cd kg–1 DW) or Cu (0, 34, or 691 mg Cu kg–1 DW) to assess the effects of non-essential (Cd) and essential (Cu) dietary metals on lipid peroxidation and the oxidative defence system. Cadmium accumulated significantly in the liver, intestine, and kidney of 204 mg Cd kg–1exposed fish compared to controls. Copper accumulated significantly in the intestine, kidney, and liver of fish exposed to 691 mg Cu kg–1, and in the intestine of 34 mg Cu kg–1 exposed fish. Tissue Cu accumulation significantly increased intestinal and hepatic lipid peroxidation (as seen from thiobarbituric acid reactive substances, TBARS, levels) and subsequently decreased intestinal -tocopherol levels and increased intestinal and hepatic selenium dependent glutathione peroxidase (SeGSH-Px) activity. Dietary Cd significantly reduced SeGSH-Px activity in the intestine and liver of 204 mg Cd kg–1 exposed fish compared to controls. No significant increase in tissue TBARS or reduction of -tocopherol levels was observed in the intestine of fish exposed to dietary Cd, with exception of the highest exposure group (204 mg Cd kg–1). Dietary Cu caused depletion of tissue Se and glutathione levels, however the reduced availability of GSH and Se did not seem to explain the differences in SeGSH-Px activity. Dietary Cu had a direct effect on lipid peroxidation at a relatively low concentration (34 mg Cu kg–1). Cadmium indirectly affected tissue lipid peroxidation by damaging the oxidative defence system at the highest dietary concentration (204 mg Cd kg–1).  相似文献   

3.
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   

4.
An 8‐week feeding trial was conducted to investigate the effect of supplemental dietary zinc sources on the growth performance and carbohydrate utilization of juvenile tilapia Smith 1840, Oreochromis niloticus × O. aureus. The goal was to compare the bioavailability of two zinc sources, zinc sulphate (ZnSO4) or zinc methionine (ZnMet), by using two practical basal diets with 350 g kg?1 (C350) or 400 g kg?1 (C400) carbohydrates based on wheat as the carbohydrate source. The results showed that fish fed with a diet supplemented with 60 mg kg?1 Zn from either ZnSO4 or ZnMet had a significantly (P < 0.05) greater specific growth rate and protein efficiency ratio than those fed with the diets of ≤30 mg kg?1 Zn. The composition of tilapia carcass was also found to be influenced by various levels of dietary zinc from the two zinc sources. The G6P‐DH in fish fed with the 20 mg kg?1 ZnMet diet and the PK levels in fish fed with 20 mg kg?1 ZnSO4 and 30 mg kg?1 ZnMet diet were significantly (P < 0.05) higher than those in fish fed with the C400 diet. The data suggest that supplemental dietary zinc from either ZnMet or ZnSO4 significantly affects the growth performance and carbohydrate utilization of tilapia.  相似文献   

5.
ABSTRACT:   Ten lots of common carp and six lots of crucian carp (each lot of 100 fish) were treated under anoxia for five days at water temperatures of 25–31°C. The average per group mortality of common carp was 17%, but none of the 600 crucian carp died. The digestive tract tissues of the common carp that died had significantly lower zinc concentrations than those that survived (59 ± 41 vs 142 ± 60 μg/[g fresh tissue], P  < 0.001). The digestive tract tissues of the crucian carp had mean zinc concentrations of 652 ± 458 μg/(g fresh tissue). One lot of common carp that had low tolerance for anoxia was fed a high zinc diet (2000 mg zinc/kg diet) for 1, 2 or 6 months and then subjected to 5 days anoxia. The survival rates of those fed the high zinc diet 1 and 2 months increased from 0 to 50%, respectively; all of fish that had fed a high zinc diet for 6 months survived. Thus, anoxia survival in common carp and crucian carp is closely related to the high concentrations of zinc in their tissues.  相似文献   

6.
To separate the connective tissue cells expressing the 43-kDa zinc-binding protein from the common carp, mucosa of the digestive tract of the fish was removed by scraping with a glass slide, and the de-mucosa tissue was digested with a collagenase type IV solution. The cells collected from the collagenase-treated suspension were rather homogeneous, and more than 90% of the cells were round with a diameter of approximately 6 μm. Significant quantities of the 43kDa zinc-binding protein were shown to be present on the cell surface of the approximately 6-μm cells. The mean zinc concentration in the cells was found to be 2.21 μg zinc/106 cells, which is approximately 20—30 times higher than that found in the other three fish species (grass carp, silver carp, tilapia), studied. The present work may provide a basis for the culture of these cells.  相似文献   

7.
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   

8.
ABSTRACT: The concentrations of Zn and sulfhydryl (SH) groups in the digestive tract tissue of common carp and some aquatic animals were studied. It was found that Zn and bound SH groups could be used as indicators for detecting the Zn-binding protein in the digestive tract tissue of common carp. The digestive tract tissue of the fish underwent subcellular fractionation, and it was found that the nuclei/cell debris fraction contained most of the DNA (85%), Na+/K+-ATPase (82%), organic phosphate (90%) and the Zn-binding protein (79%), but only part of the 5'-nucletidase and alkaline phosphatase (<23%). The nuclei/cell debris fraction of the digestive tract tissue of common carp was treated with either collagenase type I or type IV, and subfractionated by sucrose density centrifugation. It was found that treatment with collagenase type IV could release more than 50% of the Zn-binding protein, Na+/K+-ATPase and organic phosphate from collagen. Sections of digestive tract tissue of common carp were stained for Zn. It was observed that Zn can be found mainly on the edge of the epithelial layer, and everywhere in the 'membrane-like' portion of the submucosal and muscular layers. It is proposed that most of the Zn-binding protein in the digestive tract tissue of common carp is located on the basolateral plasma membranes of the epithelial cells and on the surrounding muscle cells that are attached to the collagen type IV of basal laminae.  相似文献   

9.
ABSTRACT:   The distribution of zinc (Zn) concentration in the blood and erythrocytes of common carp, grass carp, silver carp and tilapia was studied. It was found that in whole blood, the average Zn concentrations in these four species of fish (approx. 6–14 μg/[ml whole blood]) were relatively similar to those in other species of fish and mammals. However, the mean Zn concentration in the erythrocytes of common carp is approximately two times higher than the other three species of fish (approx. 5 vs approx. 2 μg/[ml whole blood]). It was found that approximately 70% of the Zn in the common carp whole blood came from its erythrocytes. In addition, approximately 43% of the Zn in the erythrocytes of common carp was found to be located on its outer plasma membranes. When an antibody against a 43 kDa Zn-binding protein, isolated from the digestive tract tissue of common carp, was used, significant quantities of the protein were shown to be present on the erythrocyte plasma membranes of common carp by an indirect immunofluorescent staining. High Zn on the outer plasma membrane of the common carp erythrocyte most probably comes from the 43 kDa Zn-binding protein.  相似文献   

10.
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   

11.
A 6‐week trial was carried out with 900 juvenile Jian carp (Cyprinus carpio var. Jian) to investigate the effects of dietary zinc on growth, body composition and intestinal enzyme activities. Diets supplemented with increasing levels (15.3, 26.9, 40.8, 58.2, 68.9 and 92.5 mg Zn kg?1) of zinc lactate were fed to Jian carp (mean initial weight 15.7 ± 0.01 g). Results indicated that per cent weight gain (PWG), feed efficiency (FE), protein efficiency ratio (PER) and lipid productive value (LPV) enhanced with dietary zinc levels up to 40.8 mg kg?1 diet (P < 0.05), and plateaued thereafter (P > 0.05). Feed intake (FI) was similar to that observed for PWG. Intestosomatic index (ISI), relative gut length (RGL), hepatopancreas protein content (HPC), intestine protein content (IPC), trypsin, chymotrypsin, lipase, amylase, alkaline phosphatase (AKP), Na+, K+‐ATPase and γ‐glutamyl transpeptidase (γ‐GT) activities were all higher by dietary zinc supplementation than zinc un‐supplementation (P < 0.05). These results suggested that zinc could promote growth and increase nutrient deposition and intestinal enzyme activities. The dietary zinc requirements (use zinc lactate as zinc source) of juvenile Jian carp (15.7–42.2 g) based on PWG and serum zinc were 48.7 and 43.2 mg Zn kg?1 diet, respectively.  相似文献   

12.
This study was conducted to study the effects of dietary zinc on lipid peroxidation, protein oxidation and antioxidant defence of juvenile Jian carp (Cyprinus carpio var. Jian) by feeding fish with increasing levels of zinc (15.3, 26.9, 40.8, 58.2, 68.9 and 92.5 mg Zn kg?1) for 6 weeks. Results indicated that malondialdehyde (MDA) content and protein carbonyls (PC) in serum were the highest in fish fed diet containing 15.3 mg zinc kg?1 diet (P < 0.05). Serum antisuperoxide anion (ASA), superoxide dismutase (SOD), glutathione peroxidase (GSH‐Px), glutathione reductase (GR) activities and glutathione (GSH) content were improved with increasing dietary zinc levels up to 40.8 mg zinc kg?1 diet (P < 0.05) and levelled off (P > 0.05). Serum antihydroxy radical (AHR), catalase (CAT) and glutathione‐S‐transferase (GST) activities followed the similar pattern to that observed in ASA. The MDA and PC levels, ASA, AHR, SOD, CAT, GPx, GR, GST activities and GSH content in intestine, hepatosomatic and muscle tissue followed the similar pattern to that observed in serum. The present results indicated that zinc decreased lipid peroxidation and protein oxidation and improved antioxidant defence in fish.  相似文献   

13.
Rainbow trout (Oncorhynchus mykiss) with a mean (sd) weight of 120 (2) g were fed diets supplemented with astaxanthin extracted from the yeast Phaffia rhodozyma (OY1 = 50 mg carotenoids kg–1 feed, OY2 = 100 mg carotenoids kg–1 feed), astaxanthin (AX = 100 mg astaxanthin kg–1 feed) and canthaxanthin (CX = 100 mg canthaxanthin kg–1 feed) for 4 weeks. Muscle analyses at the end of the experiment indicated a significantly higher carotenoid concentration in the AX group, while CX and OY1 groups were similar in spite of the differences in dietary concentration. The measure of total muscle colour difference (E* ab) between initial samples and 4 week ones was higher for the AX fish group but showed no significant difference between OY1, OY2, and CX. The hue and the reflectance ratio (R650:R510) of fish muscle increased in proportion to carotenoid intake. Digestibility (ADC) of yeast astaxanthin in OY1 and OY2 groups was significantly higher than that in the AX group. Canthaxanthin ADC was about one sixth of that of astaxanthin (AX group). Carotenoid retention in the muscle, expressed as a percentage of carotenoid intake, was higher for the AX group than that recorded for OY1 and OY2. According to ADC, carotenoid retention showed a marked lower value for the CX group. Muscle retentions were similar for astaxanthins from both sources.  相似文献   

14.
A 90‐day feeding experiment was conducted with sex reversed Nile tilapia (Oreochromis niloticus) fingerlings fed purified or practical diets supplemented with different zinc sources to evaluate fish growth performance and zinc and iron retention in fish bones, fillets, liver, skin and eyes. The relative bioavailability value (RBV) of zinc in the supplemental sources tested was also calculated. Fish were fed with isonitrogenous and isoenergetic purified or practical diets supplemented with 150 mg Zn kg?1, as zinc sulphate monohydrate (ZnSO4), zinc oxide (ZnO) or zinc amino acid complex (Zn‐AA). The feeding trial was conducted in 30, 50 L aquaria where four 0.66 ± 0.01 g (mean ± SD) fingerlings were initially stocked. No significant differences were observed for any growth performance variables (P > 0.05). In practical diets, only ZnSO4 and ZnO presented bone zinc retention similar to that for the standard zinc source. Zinc concentration in the bone of fish fed practical diet supplemented with Zn‐AA (171 ± 3.62 μg g?1) was significantly lower than that verified for the practical diets supplemented with the standard zinc source (200 ± 17.7 μg g?1) or with ZnSO4 (204 ± 19.9 μg g?1). Assuming the concentration of zinc in bones as the response criterion, the supplemental zinc RBV from ZnSO4 (105%) was higher than the RBV for Zn‐AA (95.1%) or ZnO (94.9%). Iron concentration in the bones of animals fed the non‐zinc‐supplemented purified diet was significantly higher than that observed for purified diet supplemented with Zn‐AA (P < 0,05). The results of the present work allowed us to conclude that ZnSO4 in relation to ZnO or Zn‐AA was the supplemental zinc source with higher zinc bioavailability to Nile tilapia.  相似文献   

15.
A feeding experiment was conducted to determine the dietary zinc (Zn) requirement of hybrid tilapia fed on a diet with soya bean meal as the sole protein source. The quantity of phytic acid in the experimental diet was 15.5 g kg?1. Juvenile hybrid tilapia were fed on diets containing 31–227 mg Zn kg?1 in triplicates for 6 weeks. Haematology of the fish was not affected by various dietary Zn levels. Fish fed on a diet containing 31 mg kg?1 endogenous Zn showed the lowest growth rates, feed utilization, and body and plasma Zn levels. Weight gain (WG), plasma Zn level and superoxide dismutase (SOD) activity increased when a higher quantity of dietary Zn of 127 mg kg?1 was administered to the experimental fish. Beyond this level, the values of these parameters were relatively stable. On the other hand, within the dietary Zn range tested, whole‐body Zn and ash increased with higher dietary Zn levels. Analysis using a broken‐line model showed that the dietary Zn requirements of hybrid tilapia fed on soya bean meal‐based diets containing 15.5 g kg?1 endogenous phytic acid were 115, 115 and 105 mg kg?1 based on WG, whole‐body Zn retention and plasma Zn level, respectively.  相似文献   

16.
The effect of sulfide on K+ influx pathways was measured in red blood cells (RBCs) of sulfide-sensitive rainbow trout (Oncorhynchus mykiss) and sulfide-tolerant crucian carp (Carassius carassius). In trout RBCs, maximal inhibition of Na+, K+-ATPase was attained at 10 mol l–1 sulfide and amounted to 32% without being influenced by pH between 6.7 and 8.3. Ouabain-resistant K+ influx in the absence and presence of sulfide was insignificant at pH values between 6.7 and 7.7. At higher pH values ouabain-resistant K+ influx increased, but was inhibited to about 15% by 30 mol l–1 sulfide. In RBCs of crucian carp neither Na+, K+-ATPase nor ouabain-resistant K+ influx were affected by sulfide concentrations up to 850 mol l–1. Differences in sulfide-sensitivity of K+ influx between both species can be based upon different properties of the membrane transporter themselves. The reduced Na+, K+-ATPase activity in trout RBCs may also result from a slightly reduced (by 9%) ATP level after sulfide exposure. In addition, intracellular sulfide concentrations were higher in trout RBCs as compared to crucian carp. In trout, intracellular sulfide concentrations reached extracellular levels within 5 min of incubation whereas sulfide concentrations in crucian carp RBCs remained about 2-fold lower than extracellular concentrations. Although the physiological basis of sulfide-insensitive K+ influx in crucian carp RBCs is currently unknown it may contribute to the extremely high sulfide-tolerance of this species.  相似文献   

17.
This study aimed to investigate the effect of increased zinc dietary levels on the growth performance, feed utilization, immune status and induced wound healing in European sea bass (Dicentrarchus labrax). Fish weighing 10 g were fed five diets containing organic zinc at 30, 70, 110 and 150 mg kg?1 diet and one inorganic zinc source (zinc oxide) at 150 mg kg?1 diet for a period of 12 weeks. No significant (P>0.05) differences were found in the growth performance parameters (final weight, specific growth rate), immunological indices tested (respiratory burst activity in whole blood) and the wound‐healing process. Zinc accumulation in the skin, vertebrae and liver increased significantly (P<0.01) with increased dietary zinc levels but not in muscle. The highest zinc concentrations were obtained in skin tissue, followed by vertebrae, liver and muscle tissue. Using the concentration of zinc in skin as a response criterion, broken‐line analysis showed that the supplementation of 148 mg organic Zn kg?1 diet seemed to be the optimum dietary zinc supplementation level for sea bass juveniles.  相似文献   

18.
Plant protein‐based diets are widely used for common carp (Cyprinus carpio var. Jian). The plant source antagonist, such as phytate, negatively affects the bioavailability of trace minerals, but this aspect was not considered in previous studies on this species. A 10‐week growth trial was conducted to investigate the effects of inorganic Zinc (ZnSO4·7H2O, Zn‐S) and organic Zn (2‐hydroxy‐4‐(methylthio) butanoic Zinc, Zn‐M) on growth performance, Zn retention and antioxidant responses of common carp (initial weight 10.0 ± 0.03 g). Eleven semi‐purified diets containing 7 mg/kg phytic acid were prepared with 0, 5, 20, 35, 50 and 65 mg/kg Zn from Zn‐S and Zn‐M (12.8 mg/kg Zn in basal level), respectively. The results showed that either Zn‐S or Zn‐M inclusion improved growth performance, vertebral Zn deposition and antioxidant responses of fish. The Zn requirement based on WGR, vertebrae Zn and plasma SOD were 47.0, >77.8 and 48.5 mg/kg, and 63.3, 42.2 and 36.8 mg/kg, respectively, with Zn‐S and Zn‐M as Zn sources. The relative bioavailability of Zn‐M was 2.44‐ (vertebrae Zn deposition) and 1.74‐fold (plasma SOD activity) the availability of Zn‐S in the diet of common carp. The lower growth performance and poor bioavailability in vertebrae of Zn‐S group were related to the chelating of zinc with phytic acid.  相似文献   

19.
We studied the link between high zinc levels and the extreme stress tolerance of common carp. Fish under stress showed much higher plasma cortisol levels than controls. Stress or cortisol injection induced large changes in zinc levels in the common carp but not in grass carp, silver carp or tilapia. The effect of 5 days of anoxia and 4 subsequent days of recovery on cortisol and zinc contents in the common carp was investigated. Elevated plasma cortisol resulting from anoxia was correlated with decreased zinc in digestive tract tissue and increased zinc in the head kidney. Zinc was mobilized in the common carp while under stress. Changes in cortisol and zinc contents were reversible during the subsequent recovery from anoxia. Under stress, protein-bound zinc levels increased in the head kidney cell nuclei of common carp as cortisol increased. Zinc and cortisol were bound to the same protein, which was bound to DNA. The protein is likely a glucocorticoid receptor. An increase in immature red blood cells in stressed common carp was observed. Zinc was involved in the stress erythropoiesis response. Zinc may play an important role in stress defense in the common carp via the glucocorticoid receptor.  相似文献   

20.
Arctic charr,Salvelinus alpinus L. were fed five test diets containing 0% or 1% of different polyunsaturated fatty acids (PUFA) for 93 days. The fish were injected intraperitoneally with (1–14C)–18:2(n–6) or (1–14C)–18:3(n–3), and the bioconversion to longer chain PUFA studied. The conversion rate in neutral lipids was slow, with most label found as the fatty acid injected, while extensive modification took place prior to or during incorporation into polar lipids. Linolenic acid was preferred over linoleic acid as substrate for elongation and desaturation regardless of diet. In polar lipids, the predominant products of (1–14C)–18:2(n–6) metabolism were generally 20:3(n–6) and 20:4(n–6), while 18:4(n–3), 20:5(n–3) and 22:6(n–3) were the major products of (1–14C)–18:3(n–3) metabolism. The lack of radioactivity in 22:5(n–6) suggests that 4 desaturation is specific for (n–3) PUFA. Feeding the PUFA deficient diet reduced the 5 desaturation compared to fish maintained on PUFA supplemented diets. The 6 desaturation was only reduced in fish fed C18 PUFA and injected with (1–14C)–18:3(n–3). Longer chain C20 and C22 PUFA, particularly those of the (n–3) family, exerted some inhibition on the elongation and desaturation of injected fatty acids compared to those fed C18 PUFA. The incorporation of radiolabelled fatty acids into polar lipids of fish fed a commercial diet was very low, and the desaturation neglectible in both polar and neutral lipids, showing that Arctic charr under culture conditions do not convert short chain PUFA to longer chain metabolites.  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