pH、氨氮和亚硝酸盐对单环刺螠稚螠耗氧率和排氨率的影响

Effects of pH,Ammonia Nitrogen and Nitrite on Oxygen Consumption and Ammonia Excretion of Echiuran Worm Urechis Unicinctus

在水温14.5~17.0℃、盐度32.17~32.28下,采用静水密闭式呼吸实验法研究不同pH(6.0、7.0、8.0、9.0和10.0)、氨氮(0.0699 mg/L、0.0736 mg/L、0.1560 mg/L和1.0200 mg/L)和亚硝酸盐(0.0198 mg/L、0.0256 mg/L、0.0502 mg/L、0.0738 mg/L和0.4960 mg/L)含量(用氯化铵和亚硝酸钠调制置)对体质量为(1.52±0.12)g的单环刺螠Urechis unicinctus稚螠的耗氧率和排氨率的影响。结果表明,随pH升高,单环刺螠稚螠耗氧率和排氨率先升高后降低,影响显著(P<0.05);随氨氮浓度升高,稚螠耗氧率显著降低(P<0.05),随亚硝酸盐浓度升高先增大后降低,但对排氨率影响不显著(P>0.05)。随着pH的升高O/N值先升高后降低,范围在3.911~10.484;随着氨氮浓度升高,O/N值呈下降趋势,范围在8.673~28.656;随着亚硝酸盐浓度升高,O/N值先升高后降低,范围在29.376~44.783。本实验条件下,pH低于8时能源物质为蛋白质,高于pH 8能源物质转为蛋白质和脂肪;不同氨氮浓度下脂肪均是能源物质,只是所占比例不同;不同亚硝酸盐浓度下O/N值均大于24.0,能源物质为脂肪和碳水化合物。

The effects of different pH values(6.0,7.0,8.0,9.0,and 10.0),and ammonia nitrogen(0.0699 mg/L,0.0736 mg/L,0.1560 mg/L,and 1.0200 mg/L)and nitrite contents(0.0198 mg/L,0.0256 mg/L,0.0502 mg/L,0.0738 mg/L,and 0.4960 mg/L)prepared by ammonium chloride and sodium nitrite configuration on oxygen consumption rate and ammonia excretion rate were investigated in juvenile echiuran worm Urechis unicinctus with body weight of(1.52±0.12)g by a static water closed breathing method.It was found that both oxygen consumption rate and ammonia excretion rates of juvenile echiuran worm were increased first and then decreased with the increase in pH values,with significant effects(P<0.05).The oxygen consumption rate of juvenile echiuran worm was shown to be significantly decreased with increase in ammonia nitrogen concentration(P<0.05),and ammonia excretion rate was found to be increased first and then decreased with the increase in nitrite concentration,without significant effect(P>0.05).As the pH value increased,O/N value was increased first and then decreased,ranging from 3.911 to 10.484;as the ammonia nitrogen concentration elevated,O/N value showed a downward trend,ranging from 8.673 to 28.656;as the nitrite concentration increased,O/N value was increased first and then decreased,ranging from 29.376 to 44.783.The findings indicated that juvenile echiuran worm consumed dietary protein as energy substance at pH of below 8,changing from protein to both protein and fat as energy substance at pH of over 8 under the experimental conditions.Dietary fat was considered as an energy substance under different ammonia nitrogen concentrations,with different proportions.Under different nitrite concentrations,O/N values were higher than 24.0,and the energy substances were fat and carbohydrate.