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Suwanit Chainark 《Journal Of Applied Aquaculture》2013,25(2):171-185
Three channel catfish (Ictalurus punctatus) ponds were treated at two-week intervals with sodium nitrate at 2 mg NO3 ?-N/L per application and three ponds served as controls. Average concentration of nitrite-nitrogen measured midway between application dates never exceeded 1.2 mg/L in treated ponds, but on most sampling dates, nitrate concentrations were greater than those in control ponds (P < 0.1). Disappearance of nitrate-nitrogen from waters of treated ponds resulted primarily from nitrate reduction to free nitrogen gas. Soluble reactive and total phosphorus concentrations tended to be higher (P < 0.1) in treated ponds than in control ponds. There were no differences (P > 0.1) in pH and concentrations of total alkalinity, total ammonia nitrogen, and dissolved oxygen between treated and control ponds. The higher chlorophyll a concentration (P < 0.1) suggested that greater availability of nutrients in treated ponds resulted in more phytoplankton growth than in control ponds. Because of greater phytoplankton biomass, turbidity was higher and Secchi disk visibility less in treated ponds as compared to control ponds (P < 0.1). There were no obvious differences in phytoplankton community composition with respect to treatment—blue-green algae dominated the phytoplankton community in both treated and control ponds. Redox potential in sediment during crops was higher in ponds treated with sodium nitrate than in control ponds, indicating less anaerobic conditions. However, catfish survival, production, and feed conversion ratio did not differ (P > 0.1) between treatment and control. 相似文献
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Pitchaya Chainark Shuichi Satoh Ikuo Hirono Takashi Aoki Makoto Endo 《Fisheries Science》2008,74(2):380-390
ABSTRACT: Foreign DNA fragments from genetically modified defatted soybean meal (GM SBM) in rainbow trout was traced by nested polymerase chain reaction (PCR) and located by in situ hybridization. Either a GM or non-GM SBM formulated diet (42% protein) was fed to fish (average weight 50.5 g) for 2 weeks. The degradation results showed that the cauliflower mosaic virus 35S promoter (220 bp) fragment was detected in the contents of digestive system only in fish fed the GM SBM diet, and it was not detected on the third day after changing the diet to the non-GM SBM diet. For the possible transferal results, the promoter fragment was detected in the leukocyte, head kidney and muscle only of fish fed the GM SBM diet; it was not detected on the fifth day after changing the diet to the non-GM SBM diet. These results suggest that a foreign DNA fragment was not completely degraded and might be taken up into organs through the gastrointestinal tract. However, foreign DNA was not detected after the withdrawal period. Thus, the data show that uptake of DNA from GM SBM might not remain in the tissues of fish fed GM SBM diet. 相似文献
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Availability of genetically modified soybean meal in rainbow trout Oncorhynchus mykiss diets 总被引：1，自引：0，他引：1
Pitchaya Chainark Shuichi Satoh Tokuya Hino Viswanath Kiron Ikuo Hirono Takashi Aoki 《Fisheries Science》2006,72(5):1072-1078
The use of genetically modified defatted soybean meal (GM SBM) as rainbow trout feed was investigated, in comparison with
non-GM SBM. Both SBMs were included at levels of approximately 15 and 30% in four diets (42% protein). The diets were fed
to juvenile fish (48.3 g average weight) for 12 weeks. The nutrient use showed that there was no significant difference in
growth and feed performance between GM and non-GM SBM groups at both inclusion levels at the end of 12th week. The cauliflower
mosaic virus 35S promoter fragment (220 bp) of the GM SBM was detected in the muscle of fish receiving both levels of GM SBM diet by nested
PCR, but the frequency of detection was greater at the higher inclusion level. Additionally, the promoter fragment was not
detected by the fifth day after changing the diet to non-GM. Conversely, the promoter fragment was not detected from fish
fed with the non-GM SBM diet. The results demonstrated that the availability of protein in GM SBM was similar to that of non-GM
SBM, and the promoter fragments found in the muscle of fish were not detectable after changing the diet to non-GM, verifying
the availability of the GM SBM in rainbow trout feed. 相似文献
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