Effect of ammonia to fish neutrophils and its permissible level

在25ﾟC-WT下，将0.2mlE.Coli5 mg/ml细菌溶液注入罗非鱼的膀胱内，24小时后用注射器将渗出液从膀胱腔中取出。液体中含有大量的白细胞，其中中性粒细胞占97%。中性粒细胞的分离也适用于其他淡水和海水鱼类。在中性粒细胞-Hanks平衡盐水溶液中加入0，1和2ppm的氨(NH4+.0，0.011和0.023ppm作为NH3)。在本实验中，氨对中性粒细胞的吞噬能力有抑制作用。在活体试验中，罗非鱼在氨水(0、1和2ppm氨氮，0、0.003和0.006ppm氨氮)中，在25ﾟC下保存1周，在0、1、3、7d分离中性粒细胞，进行生理分析。在本试验中，中性粒细胞的生理学不受环境氨浓度的影响。尽管水氨浓度不同，但在整个试验期内，暴露在氨水中的鱼的血氨水平几乎相同。这一结果可能与氨水对鱼的中性粒细胞生理没有影响有关。在体内氨毒性试验过程中，我们经常看到一种优势鱼对另一种从属鱼的攻击行为。与优势种相比，从属种鱼类的中性粒细胞功能显著降低。由于到目前为止，这一行为方面在鱼类免疫学中被忽视了，免疫学家应该在未来对其进行研究。

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5mg/ml) was injected into a swim bladder of tilapia under 25ﾟC-WT.At 24 hrs post-injection, the exudative fluid was withdrawn from the bladder lumen by a syringe.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.