多鳞四须鲃耗氧率、排氨率和窒息点的初步研究

控制水温在(20±0.5)℃条件下,采用Winkler法和奈氏试剂法分别测定水中的溶氧含量和氨氮含量,通过比较流水呼吸室进、出口水中的溶解氧和氨氮含量之差以确定多鳞四须鲃(Barbodes schwanenfeldi)的耗氧率、排氨率及窒息点.结果表明,多鳞四须鲃耗氧率随体重增加而减小,关系式为Y=0.24X^-0.09(R²=0.9028);随放养密度的增大而减小,关系式为Y=-0.029X+0.3301 (R²=0.9291).排氨率随体重的增加而减小,关系式为Y=-0.0008X+0.2433 (R²=0.9817);随放养密度的增大而增加,关系式为Y=-0.050X+0.4979 (R²=0.9889).多鳞四须隹巴晚间(18:00～4:00)的耗氧率明显高于白天(6:00-1:00),排氨率则相反,白天的排氨率相对较高,表明多鳞四须鲃巴属于"昼伏夜出"型鱼类.多鳞四须啬巴的窒息点为1.2572mg·L^-1,耐氧性较差.

A preliminary study on oxygen consumption rate,ammonia excretion rate and asphyxiation point of Barbodes schwanenfeldi

In the condition of a determined water temperature(20±0.5)℃,the oxygen consumption rate and asphyxiation point of Barbodes schwanenfeldi were determined through the measurement of dissolved oxygen in control and experimental respiration chambers by Winkler's method.Meanwhile,ammonia excretion rate was also determined by Nessler's reagent method.The results indicated that the oxygen consumption rate decreased gradually with increase of body weight and was shown by Y=0.24X^-0.09 (R²=0.9028);it also decreased gradually with increase of cultivation density and was shown by Y=-0.0296X+0.3301(R²=0.9291).The ammonia excretion rate decreased gradually with increase of body weight and was shown by Y=-0.0008X+0.2433(R²=0.9817);while it increased with increase of cultivation density and was shown by Y=0.0506X+0.4979(R²=0.9889).The oxygen consumption rate of B. schwanenfeldi was obviously higher during the nighttime(18:00-4:00) as compared to the daytime(6:00-16:00),which showed that B. schwanedfeldi hid in daytime and came out at night.Conversely,the ammonia excretion rate was relatively higher during the daytime. The asphyxiation point of B.schwanenfeldi was 1.2572 mg·L^-1,suggesting it had poor tolerance to low dissolve oxygen.