| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1996: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1995: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Research Abstract |
0.2ml of bacterial solution (E.coli, 5mg/ml) was injected into a swim bladder of tilapia under 25ﾟC-WT.At 24 hrs post-injection, the exudative fluid was withdrawn from the bladder lumen by a syringe. The fluid contained large numbers of leucocytes, in which neutrophils occupied >97%. This neutrophil isolation was also available to the other fresh- and seawater fishes.
Ammonia was added to the neutrophils-Hanks balanced saline solution at the concentration of 0,1, and 2ppm (as NH4+.0,0.011, and 0.023ppm as NH3). In this in vitro ammonia toxicity, the ammonia depressed the phagocytic ability of neutrophils. For in vivo test, tilapia was kept in ammonia water (0,1, and 2ppm as NH4+, 0,0.003, and 0.006ppm as NH3) for one week under 25ﾟC.The neutrophils were isolated to analyze their physiology in the 0,1st, 3rd, and 7th day. In this test, the neutrophil physiology was not affected by the ambient ammonia concentrations. The blood ammonia levels of the fish exposed to the ammonia water were almost same through the whole test period despite the different water ammonia concentraions. This result is probably responsible for the noinfluence on the neutrophil physiology of the fish kept in ammonia water.
On the process of in vivo ammonia toxicity test, we frequently saw aggressive behavior of a dominant fish to a subordinate one. The neutrophil function was drastically depressed in the subordinate fish compared to the dominant. Because this behavioral aspect has been overlooked in fish immunology so far, the immunologist should develop it in future.
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