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1.
Effects of dietary carbohydrates on hepatic antioxidant enzymeactivities were studied in Atlantic salmon (Salmo salarL.), fed diets containing no additional carbohydrate, or a low (15% addition)orhigh (30% addition) concentration of D-glucose or gelatinised potato starch.Addition of free glucose to the feeds resulted in glucose availability being 7and 18% when added at 15 and 30%, while the addition of gelatinised starch didnotseem to reduce starch availability. The dietary treatment groups (nocarbohydrate, 7 and 18% glucose or 15 and 30% gelatinised starch) were providedwith quantities of feed that supplied the same amounts of protein and lipid.There was a positive correlation between tiobarbituric acid-reactive substances(TBARS) in feeds and salmon liver. Liver glycogen concentrations increased withincreasing dietary glucose and starch, and the two higher levels of liverglycogen, found in groups G18 and S30, resulted in decreased activities ofcatalase, superoxide dismutase (t-SOD), and concentrations of glutathione. Thisindicates that there are links between carbohydrate metabolism and antioxidantsystems in salmon liver. There was no correlation between selenium dependentglutathione peroxidase (Se-GPX) activity and dietary carbohydrateconcentrations, but Se-GPX activity increased in response to increased TBARS.Catalase and t-SOD activities did not correlate with either TBARS values orSe-GPX activity. 相似文献
2.
Variation in growth rate,liver weight and body composition at first sexual maturity in rainbow trout
Bjarte Tveranger 《Aquaculture (Amsterdam, Netherlands)》1985,49(2):89-99
Rainbow trout around 743 g were fed four different diets over an 8-month period. Maturing males grew faster in the period before spawning (Sept.–Dec.) than maturing females, and significantly faster than immature fish. Mature fish stagnated in growth while the immature fish surpassed the growth of mature fish during the spawning season. The condition factor was moderately influenced by the maturation process. In the period before spawning (Sept.–Jan.) maturing females had a significantly higher hepatosomatic index than males and immature fish. An increase in dry matter and fat and a decrease of protein were observed in the muscle of maturing males and immature fish towards the spawning season, while maturing females had a slight fall in dry matter and fat and a small increase in protein in the same period. Dry matter and fat in muscle of rainbow trout were positively correlated. 相似文献
3.
Atlantic salmon were fed 40, 300 or 1100 mgall-rac--tocopheryl acetate kg feed–1 for 12 weeks.After 6 weeks half of the fish in each group were marked and vaccinated (i.p.injection) against furunculosis and vibriosis. Liver -tocopherol levelsreflected the dietary input after 6 and 12 weeks of feeding. Noimmunomodulatoryeffects of dietary vitamin E on baseline levels of the immune parameters beforevaccination were detected in this study, as evaluated by antibody dependent andspontaneous plasma complement activities. In general, vaccination increasedplasma complement activities and the number of antigen specific antibodyproducing cells as compared with unvaccinated control fish, but with nodifferences with respect to the vitamin E regimes. Also the ability ofunvaccinated fish to withstand experimental furunculosis was unaffected bydietary vitamin E. The concentrations of -tocopherol and ascorbic acidinthe liver were, however, negatively affected 6 weeks post vaccination comparedto respective unvaccinated fish. 相似文献
4.
Manganese requirement of Atlantic salmon (Salmo salar) fry 总被引：1，自引：0，他引：1
5.
Effect of induced hyperoxia on the antioxidant status of Atlantic salmon Salmo salar L. fed three different levels of dietary vitamin E 总被引：4，自引：0，他引：4
Atlantic salmon smolt (64 g) were fed 40, 300 or 1100 mg kg?1 all‐rac‐α‐tocopheryl acetate feed under normoxic and moderate hyperoxic conditions for 12 weeks. After 7 weeks, however, the hyperoxic fish were subjected to a temporary severe supersaturation of dissolved oxygen with development of gas bubble disease and substantial mortality as a result. Liver α‐tocopherol (α‐TOH) levels reflected the dietary input after 6 and 12 weeks of feeding. Increased levels of thiobarbituric‐reactive substances (TBARS) in the liver of hyperoxygenated fish after 6 weeks indicate that moderate hyperoxic conditions may represent an oxidative challenge to the fish. After 12 weeks, liver ascorbic acid (AA) content was reduced in hyperoxygenated fish, and a decreasing tendency was also found in the liver content of α‐TOH. Effects of oxygen supersaturation were also observed on liver antioxidant enzyme activities, content of glutathione and total mercapthans in liver, phagocytic chemiluminescent response and total plasma protein level, indicating a disturbed redox balance. No effects of dietary vitamin E were observed on any of the measured parameters, indicating that high levels of dietary vitamin E under these circumstances did not protect the fish against oxidative stress. 相似文献
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7.
The Phanerozoic fossil record of marine animal diversity covaries with the amount of marine sedimentary rock. The extent to which this covariation reflects a geologically controlled sampling bias remains unknown. We show that Phanerozoic records of seawater chemistry and continental flooding contain information on the diversity of marine animals that is independent of sedimentary rock quantity and sampling. Interrelationships among variables suggest long-term interactions among continental flooding, sulfur and carbon cycling, and macroevolution. Thus, mutual responses to interacting Earth systems, not sampling biases, explain much of the observed covariation between Phanerozoic patterns of sedimentation and fossil biodiversity. Linkages between biodiversity and environmental records likely reflect complex biotic responses to changing ocean redox conditions and long-term sea-level fluctuations driven by plate tectonics. 相似文献
8.
Effects of dietary carbohydrates on hepatic antioxidant enzymeactivities were studied in Atlantic salmon (Salmo salarL.), fed diets containing no additional carbohydrate, or a low (15% addition)orhigh (30% addition) concentration of D-glucose or gelatinised potato starch.Addition of free glucose to the feeds resulted in glucose availability being 7and 18% when added at 15 and 30%, while the addition of gelatinised starch didnotseem to reduce starch availability. The dietary treatment groups (nocarbohydrate, 7 and 18% glucose or 15 and 30% gelatinised starch) were providedwith quantities of feed that supplied the same amounts of protein and lipid.There was a positive correlation between tiobarbituric acid-reactive substances(TBARS) in feeds and salmon liver. Liver glycogen concentrations increased withincreasing dietary glucose and starch, and the two higher levels of liverglycogen, found in groups G18 and S30, resulted in decreased activities ofcatalase, superoxide dismutase (t-SOD), and concentrations of glutathione. Thisindicates that there are links between carbohydrate metabolism and antioxidantsystems in salmon liver. There was no correlation between selenium dependentglutathione peroxidase (Se-GPX) activity and dietary carbohydrateconcentrations, but Se-GPX activity increased in response to increased TBARS.Catalase and t-SOD activities did not correlate with either TBARS values orSe-GPX activity. 相似文献
9.
As the world's oceans continue to undergo drastic changes, understanding the role of key species therein will become increasingly important. To explore the role of Atlantic cod ( Gadus morhua Gadidae) in the ecosystem, we reviewed biological interactions between cod and its prey, predators and competitors within six ecosystems taken from a broad geographic range: three are cod-capelin ( Mallotus villosus Osmeridae) systems towards cod's northern Atlantic limit (Barents Sea, Iceland and Newfoundland–Labrador), two are more diverse systems towards the southern end of the range (North Sea and Georges Bank–Gulf of Maine), and one is a species-poor system with an unusual physical and biotic environment (Baltic Sea). We attempt a synthesis of the role of cod in these six ecosystems and speculate on how it might change in response to a variety of influences, particularly climate change, in a fashion that may apply to a wide range of species. We find cod prey, predators and competitors functionally similar in all six ecosystems. Conversely, we estimate different magnitudes for the role of cod in an ecosystem, with consequently different effects on cod, their prey and predator populations. Fishing has generally diminished the ecological role of cod. What remains unclear is how additional climate variability will alter cod stocks, and thus its role in the ecosystem. 相似文献
10.
Design and operations of the Kaldnes moving bed biofilm reactors 总被引：10，自引：0，他引：10
Bjorn Rusten Bjrnar Eikebrokk Yngve Ulgenes Eivind Lygren 《Aquacultural Engineering》2006,34(3):322-331
The moving bed biofilm reactor (MBBR) was developed in Norway in the late 1980s and early 1990s. It is covered by several patents and has been a huge success world-wide for treatment of municipal and industrial wastewaters. In addition, MBBRs have been successfully used for biological treatment of drinking water as well as for water treatment in fish farms. The MBBRs use plastic biofilm carriers of a unique design, to maximize the active biofilm surface area in the reactors. Reactors have insignificant headloss, no need for periodic backwashing and no susceptibility for clogging. This paper describes the fundamentals of the MBBR. It has a major emphasis on nitrification with the type of biofilm carrier used in fish farms, but briefly touches upon removal of organic matter and denitrification. Major factors influencing the nitrification rates in MBBRs are discussed in detail. Results from small-scale MBBR tests, as well as from commercially operated MBBRs at full scale fish farms are presented. The data are from both freshwater and marine applications. 相似文献