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1.
Atlantic salmon, Salmo salar L., (14 g) were fed a practical fish-meal-based diet supplemented with 0. 10, 20. 40, 80 and 160 mg pyridoxine (PN) per kg feed for 20 weeks. Tissue vitamin B6 contents were significantly reduced in fish fed the non-supplemented diet compared with fish fed PN-supplemented diets. Serum haemolytic complement activity and head kidney lysozyme activity, and the specific antibody response following immunization with Vibrio salmonicida. were not influenced by the dietary regimes. Challenge with Aeromonas salmonicida showed that increasing the dietary levels of vitamin B6 did not improve the resistance to furunculosis. Growth, mortality and haematology were not affected by supplementing a practical diet with vitamin B6 In conclusion, feed levels of vitamin B6 higher than the minimum dietary requirement did not enhance immune functions and disease resistance in Atlantic salmon.  相似文献   

2.
Abstract. An insoluble polysaccharide from the cell wall of Saccharomyces cerevisiae , called M-Glucan, has been shown to enhance the non-specific disease resistance of Atlantic salmon, Salmo salar L., when injected intraperitoneally. M-Glucan consists only of glucose units which presumably are linked through β -1,3 and β -1,6 linkages. Enhanced resistance was demonstrated against Yersinia ruckeri , the causal agent of enteric redmouth disease, against Vibrio anguillarum , the causal agent of classical vibriosis and against Vibrio salmonicida , which causes cold water vibriosis or 'Hitra-disease' in salmon. At a dose of 2mg M-Glucan per fish (20g mean weight), maximal resistance developed in the fish 3 weeks after injection. Injection of different glucan doses and challenge one week later with Vibrio anguillarum , showed that 50-200μg glucan per fish resulted in the highest level of resistance. The level of resistance in Atlantic salmon obtained with M-Glucan was strikingly higher than that obtained with another glucan which was prepared from Saccharomyces cerevisiae by a different procedure.  相似文献   

3.
Presmolt Atlantic salmon were fed a fish meal based experimental diet supplemented with graded levels of ascorbate-2-monophosphate (AP), equivalent to 40, 400, 2000 and 4000 mg ascorbic acid (AA)/kg for 6 months prior to a bacterial challenge experiment. The liver AA concentration reflected the dietary intake of AP, but not linearly. Growth, hematology and acid phosphatase activity in zymosan stimulated macrophages were not affected by dietary AP. Serum hemolytic complement activity was higher in fish fed the highest AP level, but the variation was not significant. Production of specific antibodies was significantly higher in fish fed the highest AP level 11 and 17 weeks after vaccination. Bacterial challenge with Aeromonas salmonicida showed increased survival in the 4000 AP group. Lysozyme activity in headkidney and serum complement activity and serum iron in fish surviving the challenge were higher in the 4000 AP group, indicating important roles of vitamin C on lysozyme, complement and iron in non-specific disease resistance. The results indicate that high dietary levels of AP favourably affect health in Atlantic salmon. Disease resistance was, however, not correlated with the AA status in the liver.  相似文献   

4.
The retention of vaccine components was studied in Atlantic salmon, Salmo salar L., following different routes of vaccination against Aeromonas salmonicida. Frozen tissue was collected from the spleen, head kidney, hind gut and liver of fish that had been vaccinated by intraperitoneal injection (monovalent and trivalent vaccines), immersion and oral administration 2,6,8 and 16 weeks previously. The trivalent injection group showed the highest levels of specific antibodies and was the only group to show protection following challenge with virulent A. salmonicida. Following intraperitoneal injection, there was an initial widespread distribution of Aeromonas lipo-polysaccharide, but by 16 weeks lipopolysaccharide was predominantly found in macrophage populations in the spleen, head kidney and abdominal granulomas. Only small amounts of lipopolysaccharide were retained in the head kidney of the immersion group and no lipopolysaccharide was retained in the oral group. Small and inconsistent amounts of A-layer protein were present in the meianomacrophages of the head kidney of all groups. The relative prominence of A-layer protein in the spleen of the trivalent injection group 8 weeks after vaccination was linked to the high levels of specific antibodies, and possible immune-complex trapping and the enhancement of immunological memory.  相似文献   

5.
Abstract. Both under-yearling and post-yearling Atlantic salmon parr produced high agglutinating antibody titres in response to a single intraperitoneal injection of killed bacterial kidney disease (BKD) cells emulsified in. Freund's complete adjuvant (FCA), Low or no response was observed in animals injected with BKD cells in saline or in animals vaccinated by hyperosmotic immersion. Immunological duration was insufficient in fish vaccinated as under-yearling parr to provide protective immunity 2 years later when the fish had become smolts. Atlantic salmon post-yearling parr injected with BKD cells in FCA demonstrated a reduced prevalence of BKD lesions compared to control animals when both were observed as smolts 1 year after vaccination.  相似文献   

6.
Abstract. Atlantic salmon, Salmo salar L., responded to intraperitoneal injection of formalin killed Vibrio salmonicida or live infectious pancreatic necrosis virus ( ipnv ) by producing specific antibodies. The antibody titre varied significantly within the group tested. Western blot analysis demonstrated that high-titre antisera recognized two major bacterial antigens with molecular weights of 12–15 kD and 22–27 kD. In addition, a few narrow bands with higher molecular weights were observed. An antiserum raised against IPNV recognised two major antigens corresponding to the structural proteins of the virus. E lisa and Western blot analysis showed that the immune serum raised against Vibrio salmonicida reacted slightly with Vibrio anguillarum , whereas no reaction to Yersinia ruckeri or Aeromonas salmonicida was detected. Indirect elisa and an elisa competition assay revealed that the immune serum raised against the N1 serotype was specific for this serotype of ipnv . The results demonstrate that Atlantic salmon has a humoral immune system capable of producing antibodies which discriminate between related bacterial antigens and between different serotypes of a virus.  相似文献   

7.
Two trials were initiated to investigate the consequences of including various soybean products in diets for Atlantic salmon Salmo salar L. on (1) mortality following infection by Aeromonas salmonicida ssp. salmonicida during a cohabitation challenge, and (2) the lysozyme and IgM content of the intestinal mucosa. Groups of salmon were fed control diets containing fishmeal as the sole protein source (Contr1 and Contr2, respectively), soy concentrate-containing diets (SoyConc1 and SoyConc2, respectively), or diets containing either solvent-extracted soybean meal (SoyMeal, trial 1) or soybean molasses (SoyMol, trial 2), an alcohol extract of soybean meal. Both SoyMeal and SoyMol caused enteritis-like changes in the distal intestine, which were not observed in fish fed the Contr1, Contr2, SoyConc1, or SoyConc2 diets. There were significant differences ( P  < 0.05) in mortality between feeding groups following the A.s. salmonicida challenge: these differences were greatest in fish fed SoyMeal (65.6%), least in fish fed SoyConc1 (60.5%), and intermediate in the fish fed the Contr1 diet (62.9%). The SoyMol diet caused significantly ( P  < 0.0001) increased levels of both lysozyme and IgM in the mid and distal intestinal mucosa. It is concluded that components of soybean meal and soybean molasses cause an inflammatory response in the distal intestine that may lead to increased susceptibility to furunculosis.  相似文献   

8.
Abstract. The retention of vaccine components and phenotypes of leucocyte populations were examined in the spleen of Atlantic salmon, Salmo salar L., 12 weeks after intraperitoneal administration of three different furunculosis vaccines. There were marked differences between the vaccine groups as judged by serum antibody response and survival following challenge with Aeromonas salmonicida. Abundant vaccine components were present in the spleen following administration of the two adjuvanted vaccines but not the non-adjuvanted vaccine. The non-adjuvanted group showed a disrupted pattern of silver staining in the splenic ellipsoids, suggesting possible toxic changes. Altered levels of enzyme reactivity in the spleens of vaccinated fish suggested activation of macrophages. Computer-assisted morphometric analysis was used to demonstrate that a significant ( P < 0.05) increase in acid phosphatase reactivity associated with the melanomacrophage accumulations only occurred in the group that had shown a good response to challenge (14% mortality when control group = 60%), and a high level of anti- A . salmonicida antibodies. The findings of the present study suggest that the retention of antigen and the activation of macrophages in melanomacrophage accumulations of Atlantic salmon are of significance in vaccination against furunculosis.  相似文献   

9.
Individually tagged Atlantic salmon, Salmo salar L., were fed three different adaptation diets containing low, medium or high levels of extruded starch, before intraperitoneal injection of glucose. The injections were done at winter and at summer temperatures. This was to investigate whether the tolerance for glucose varied according to adaption diet and/or according to season. The results showed a temperature-dependent response. At winter temperatures (2°C) the Atlantic salmon had problems adapting to both medium and high levels of dietary starch. This was indicated by lower growth response in the adaptation period, as well as by delayed glucose regulation. At summer temperatures (12.5°C) the Atlantic salmon could tolerate and utilize both medium and high levels of dietary starch. In summer also all groups responded evenly to the tolerance tests with respect to blood glucose regulation. Incorporation of liver glycogen was higher at summer than at winter temperatures in the high- carbohydrate group. No effect was found on haematocrit values as a response to diet or season.  相似文献   

10.
Aerobic heterotrophic bacteria were isolated from the intestinal contents of Atlantic salmon, Salmo salar , rainbow trout, Oncorhynchus mykiss , and turbot, Scophthalmus maximus , on tryptone soya agar and De Man Rogosa and Sharpe agar, of which 11 of 177 (6% of the total) of the isolates were antagonistic to Aeromonas salmonicida . Four of these cultures, which were identified tentatively as A. hydrophila , Vibrio fluvialis , Carnobacterium sp. and an unidentified Gram-positive coccus, were beneficial to fish when fed singly or as an equi-mixture. Feed supplemented with the putative probiotics indicated survival of the organisms in the gastrointestinal tract for 7 days. Feeding with the probiotics for 7 and 14 days led to better survival following challenge with A. salmonicida . There was no indication of serum or mucus antibodies to A. salmonicida , but there was an increased number of erythrocytes, macrophages, lymphocytes and leucocytes, and enhanced lysozyme activity in the fish.  相似文献   

11.
Atlantic salmon (Salmo salar) parr were fed fish meal based pelleted diets supplemented with graded levels of ascorbate-2-monophosphate (AP), equivalent to 0, 20, 60 and 1000 mg ascorbic acid (AA) kg”1 throughout smoltification on a continuous light regime from February to June. No differences were observed in growth rate and body length distribution between the dietary regimes. The condition factor and the hepatosomatic index were somewhat elevated in fish fed no vitamin C throughout the smoltification, which can reflect changes in lipid metabolism in fish with suboptimal vitamin C nutrition. Sea water challenge tests (exposure to sea water with salinity of 34 gL?1 and ambient temperature for 24 h) performed monthly did not reveal differences attributed to the vitamin C status, as measured by mortality, serum chloride and cortisol concentrations, haematological parameters and liver and head kidney ascorbate concentrations after 24 h. Elevated serum cortisol concentrations most probably reflected stress in the challenge tests, and some lower concentrations in fish fed high vitamin C levels may indicate a certain stress-ameliorating effect. The present results do not, however, support the anticipation of increased requirement of dietary vitamin C above the minimum requirement during smoltification in Atlantic salmon.  相似文献   

12.
The development of cataracts in Atlantic salmon, Salmo salar L., was studied in 16 groups of smolts fed diets differing in prooxidant (iron, copper, manganese) and antioxidant (vitamin E, vitamin C, astaxanthin) composition and lipid level for 23 weeks in sea water, using a 2(7-3) reduced factorial design. The seven dietary variables were systematically varied at low (requirement level and 150 g lipid kg(-1)) and high levels (below known toxic levels and 320 g lipid kg(-1)). A mean endpoint cataract incidence of approximately 36% was observed. High dietary levels of vitamin C and astaxanthin reduced cataract frequency, whereas high dietary lipid level, iron and manganese were associated with increased cataract frequencies. Considering the nutritional status of selected organs of the fish, only the status of ascorbic acid correlated negatively to cataract development (P < 0.05). The lens glutathione (GSH) status was not correlated to cataract frequency, nor statistically explained by the dietary variables. However, the study shows that balancing the diet with respect to pro- and antioxidant nutrients may significantly protect Atlantic salmon against development of cataracts. An incidence of reversible osmotic cataract observed at week 14 was positively correlated to plasma glucose concentration.  相似文献   

13.
The present study evaluated how different photoperiods, carbohydrate sources and inclusion levels influenced growth, plasma, organ and body compositions in Atlantic salmon (Salmo salar). Four different diets were used, containing 10 or 20% starch on a dry matter basis, using gelatinized corn (C10 and C20) or wheat (W10 and W20). Two different photoperiods were used, Continuous (Con) light throughout the study, Winter (Wi) two initial weeks of continuous light, thereafter 6 weeks of short day, ending with 6 weeks of continuous light. The winter regime resulted in reduced growth rate compared with continuous light. All Wi groups were smaller than Con groups when the experiment was terminated, except for fish given diet C10. Diet W10 resulted in better growth compared with all other groups when exposed to Con. regime. Atlantic salmon fed with diets containing 20% starch had lower growth rates than fish fed diets containing 10% starch, when the same starch source and light regime were compared. All fish belonging to the Con group exhibited similar and higher condition factors compared with fish from groups Wi. Condition factor was not influenced by dietary starch source. Higher whole body lipid concentrations were found when fish were given the corn compared with the wheat diets, without any responses to starch level or light regime. Whole body protein showed increased values in fish exposed to regime Wi compared with Con, without any influence from dietary manipulation. Liver glycogen values and hepatosomatic index reflected dietary starch levels and were significantly influenced by light regime, whilst muscle glycogen levels varied only as a response to light regime with lower values in fish from the Wi compared with the Con groups. Light regime influenced plasma glucose levels, except in groups fed with diet W10. All measured plasma nutrient concentrations were within normal ranges. At the end of the feeding period, all fish were evaluated for glucose and salt water tolerance to ascertain whether diet and/or light regime influenced glucose regulation capacity and/or smolt quality. Fish fed with 20% starch had reduced osmoregulatory ability measured as plasma chloride after a seawater challenge test. Fish from the Wi regime, but not from the Con regime developed characteristics associated with smoltification. Glucose tolerance in Atlantic salmon was substantially influenced by both photoperiod regime and diet. Fish reared under the Wi photoperiod showed reduced glucose regulation capacity compared with fish held under continuous light. Glucose regulation capacity was also reduced in fish adapted to the highest starch levels.  相似文献   

14.
A two-factor study was conducted to evaluate the effects of dietary riboflavin and lipid levels on the growth, health performance and riboflavin status of Atlantic salmon ( Salmo salar ). Atlantic salmon parr were fed four fishmeal-based diets with or without supplementation of 20 mg riboflavin kg–1, at two lipid levels, 150 or 300 g kg–1. Each diet was fed to triplicate tanks of fish for 12 weeks. Unsupplemented diets contained between 6 and 8 mg riboflavin kg–1. There were no significant differences in growth as a result of riboflavin supplementation. No mortality or histomorphological changes in eye tissues were observed. Dietary treatments did not affect blood haemoglobin values. After 12 weeks, muscle lipid content seemed to be reduced by riboflavin supplementation irrespective of dietary lipid level. Riboflavin status of whole body, muscle, liver, kidney and eye lenses is reported. Saturation levels of riboflavin in liver and muscle were reached with unsupplemented diets. The concentrations of riboflavin and lipid in liver were negatively correlated. There was a tendency of higher whole body riboflavin concentration in fish fed high-lipid diets. Based on growth, absence of deficiency signs and maximal tissue saturation of riboflavin, it can be concluded that the requirement for riboflavin was met by the natural riboflavin content in the raw materials of the feed. However, independent of dietary lipid level, dietary riboflavin supplementation may increase lipid utilization in rapidly growing salmon parr.  相似文献   

15.
Abstract. Parr of Atlantic salmon, Salmo salar L., were fed semi-purified diets supplemented with 60 mg astaxanthin kg−1 and without astaxanthin supplementation for 10.5 months. The astaxanthin concentration in the non-supplemented diet was analysed to be 6–0 mg kg−1 The growth of the fish was significantly affected by the dietary treatment. The mean daily weight gain in the groups fed the supplemented diets was 0.39% throughout the period, whereas the groups fed the non-supplemented diet had a mean daily weight gain of 0.18%. The dry matter and fat content were significantly higher in fish fed the supplemented diet. The astaxanthin concentration in the muscle of fish fed the astaxanthin-supplemented diet was 2–7 mg kg−1 versus 0–3 mg kg−1 in the non-supplemented fish. Antioxidant vitamins in the muscle (retinol, α-tocopherol) and liver (retinol, α-tocopherol and ascorbic acid) were two to 20 times higher in the fish in the supplemented group, suggesting antioxidant sparing effects. Blood haemoglobin and immunological parameters tended to be higher in fish fed the low astaxanthin diet although the difference was not significant. However, the resistance to challenge with Aeromonas salmonicida was higher in fish fed the astaxanthin supplemented diet. This may be due to a difference in weight at the time of the challenge which, in turn, may have influenced the body composition and smoltification of the fish. A relationship between dietary astaxanthin concentration and antioxidant status in both liver and muscle was observed, and this may also have had an influence on the observed differences in blood parameters and disease resistance.  相似文献   

16.
Genetic variation in susceptibility of Atlantic salmon, Salmo salar L., to furunculosis, bacterial kidney disease (BKD) and cold water vibriosis was studied by challenge testing one-year-old fingerlings. Fish from 81 full-sib families within 32 sire progeny groups were infected with Aeromonas salmonicida, Renibacterium salmoninarum and Vibrio salmonicida. Estimated heritabilities were relatively low, being highest for BKD (h2= 0.23) and lowest for cold water vibriosis (h2= 0.13). Genetic correlations between the ability to survive the diseases were all positive, but the magnitude of the genetic correlation between furunculosis and BKD may be biased upwards because some of the dead BKD fish were also infected with furunculosis. The application of selection to develop resistant populations of Atlantic salmon is advocated. Challenge testing seems to be a feasible method, with relatively low costs and easy management. The future response to selection will depend on the relationships between results from a challenge test and mortalities under farming conditions and between disease resistance and other traits in the breeding goal.  相似文献   

17.
An experiment was conducted to study dietary fat type (fish oil (FO) vs. vegetable oil) effect on lipid and glucose metabolism in post-smolt Atlantic salmon. Duplicate groups of salmon were fed one of eight diets in which the two fat sources FO (long chain n-3 fatty acids, FA) or linseed oil (LO) (short chain n-3 FA) were combined in a 2 × 4 factorial design with sunflower oil (SO) (rich in n-6 FA) at inclusion levels of 0, 25, 50 and 75% of total added fat. The effects of the diets on plasma metabolites, the activity of selected enzymes involved in lipid metabolism, biometric indices and muscle glucose transporter GLUT4 expression were determined after 12 weeks of feeding. Lower viscero-somatic indices (VSI) and fatty livers were observed in fish fed LO based diets. Increasing inclusion levels of SO affected plasma glucose concentration in fish fed FO based diets, and plasma triglycerides, which decreased in a linear and quadratic pattern in fish fed FO based diets, but increased linearly in fish fed LO based diets. Specific activity of liver carnitine palmitoyl transferase I (CPT I) and glucose-6-phosphate dehydrogenase (G6PD) and plasma nonesterified fatty acids (NEFA) concentration was higher in fish fed LO based diets. Two GLUT4 isoforms I and II have been described in muscle and proved to be differentially expressed related to dietary fatty acids. In summary, dietary fat type affects lipid metabolism in post-smolted Atlantic salmon. In addition, a possibility to interfere on glucose metabolism by means of dietary fat type is discussed.  相似文献   

18.
Abstract. An atypical strain of Aeromonas salmonicida was isolated from goldfish. Carassitis auraius L., with cutaneous ulcerativc lesions. Atlantic salmon, Salmo salar L., weighing 30–40 g were challenged parentcrally and by hath immersion with this strain. It was found to be highly virulent in both forms of challenge and was capable of achieving an LD50 of three colony-forming units in parenterally challenged fish. The gross lesions and histopathology of infected fish bore a close resemblance to classical furunculosis in salmonids. Goldfish ulcer disease is endemic to some regions of Australia and represents a potential threat to the emerging salmonid farming industry.  相似文献   

19.
Abstract. The level of protective immunity in rainbow trout, Salmo gairdneri Richardson, following vaccination by intraperitoneal (i.p.) injection or by direct immersion with Vibrio anguillarum was studied over a period of 46 weeks. Antibody titres to V. anguillarum O-antigen were determined with ELISA at the time of each experimental infection to study the relation between specific antibody production and protective immunity. Both vaccination by i.p. injection and vaccination by direct immersion induced a high degree of protective immunity against vibriosis which lasted for at least 46 weeks. At each experimental infection, the proportions of seropositive fish were lower than the proportions of fish with protective immunity. However, seropositive individuals were found in both experimental groups throughout the study.  相似文献   

20.
Abstract. Typical Aeromonas salmonicida with similar biochemical characteristics to A. salmonicida from Atlantic salmon, was isolated from wrasse, Ctenolabrus rupestris (L.) and Centrolabrus exoletus (L.), stocked as cleaner fish with these salmon. Although no external clinical signs were apparent, localized bacterial microcolonies were observed in muscle, gills, intestine, kidney and myocardial tissue. Mortalities attributed to A. salmonicida comprised 55% (n = 32) of total mortalities. No carriers of A. salmonicida were found in wild wrasse following stress testing. Although salmon post-smolts died when challenged with 1 × 105 ml-1 of a virulent strain, there were no mortalities in challenged wrasse. An oral route of infection is suggested rather than water-borne transfer as wrasse browsed on salmon mortalities. Wrasse were treated for A. salmonicida infection by injection with antibiotic and were also vaccinated, and in the latter case, elevation of antibody levels was noted.  相似文献   

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