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J. Olah 《Aquaculture (Amsterdam, Netherlands)》1984,37(2):185-186
A solar-heated greenhouse containing recirculating fish production systems was used to culture Tilapia nilotica and T. aurea. Fish production was maximized by sequential rearing, grading, and restocking of fish at high densities to utilize each system fully. Marketable-size (167 g) fish were produced from 29-g fingerlings in 137 days. No reproduction was recorded.Spawning in February was induced naturally by a photoperiod, water temperature of 24°C, and reducing stock density. 相似文献
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J.Carl Mundt 《Aquaculture (Amsterdam, Netherlands)》1984,38(3):275-276
In the present communication the gross symptoms of severe riboflavin deficiency are reported as observed in six experiments conducted with four independent stocks of rainbow trout fry and fingerlings. Unlike other reports on salmonids, ocular opacities were infrequently observed, and neither their rate of incidence nor their severity was related to dietary riboflavin content. Compared with both satiety-fed and pair-fed controls, riboflavin-deficient trout exhibited lethargy, apparent muscular weakness, reduced appetite and growth rate, severe fin erosion (all fins), rapid opercular movements, light greenish-yellow skin coloration and high mortality rate. These symptoms, although due to riboflavin deficiency per se, are nonspecific. As the cataracts produced by others in riboflavin-deficient trout appear to be a specific, diagnostic symptom, it is important to identify those conditions which can preclude their development in riboflavin deficiency. 相似文献