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在25±1℃下,使尼罗罗非鱼(Oreochromis niloticus)预先适应正常氧含量(PO_2≥125mmHg;S=90%),然后,在不同浓度的低氧含量下,测定其摄氧量(VO_2)和呼吸参数。随着吸入水中 P_1O_2的减小,VO_2略增;鳃通量(V_G)激增,并导致呼吸量(V_(S,R))的显著增加,而呼吸频率(f_R)几乎不变。摄氧率(EO_2)的减小也伴随着 V_G 的增加。在正常氧含量下,鳃呼吸代谢耗氧量为总 VO_2的3%,但在严重缺氧(P_1O_2=30mmHg;S=21%)时,则增至18%。可见,该种鱼不能长期处于低氧环境中,因为部分代谢能将被呼吸系统用于维持摄氧量,从而削弱了其他代谢功能,如增重与生长。
Oreochromis niloticus was preconditioned to normal oxygen content (PO 2 ≥ 125 mmHg; S = 90%) at 25 ± 1 ° C, and then its oxygen uptake was measured at different concentrations of hypoxia VO_2) and breathing parameters. With the decrease of P 1 O 2 in inhaled water, VO 2 slightly increased; the gill flux (V_G) increased sharply, leading to a significant increase of respiration (V_ (S, R)) while the respiratory frequency (f_R) hardly changed. The reduction of oxygen uptake (EO 2) is also accompanied by the increase of V_G. At normal oxygen level, the gill respiratory metabolic oxygen demand was 3% of the total VO_2, but increased to 18% at severe hypoxia (P 1 O 2 = 30mmHg; S = 21%). It can be seen that the fish can not be exposed to hypoxia for a long time because some of the metabolism will be used by the respiratory system to maintain oxygen uptake, thus impairing other metabolic functions such as weight gain and growth.