氨对长毛对虾幼体的毒性

Toxicity of ammonia to larvae of Penaeus penicillatus

氨对长毛对虾（Penaeuspenicillatus）各期幼体的毒性试验表明：状幼体对氨最敏感，而仔虾幼体对氨的耐受性最强。在盐度32，pH8．20，水温29．0℃时，无节幼体Ⅲ期（N3）、状幼体Ⅰ期（Z1）、糠虾Ⅰ期（M1）、仔虾第五天（P5）24h的LC50值分别为13．20（1．15）、997（0．87）、26．99（2．35）和60．81mg／dm3∑NH＋4（NH3）－N1)（5．30gm／dm3NH3－N）。Z1、M1、P5的48h的LC50值分别为5．21（0．45）、14．86（1．29）和32．85mg／dm3∑NH＋4（NH3）－N（2．86mg／dm3NH3－N）。P572h和96h的LC50值分别为19．62（1．71）和11．95mg／dm3∑NH＋4（NH3）N（1．04mg／dm3NH3－N）。长毛对虾幼体耐受氨的安全含量为1．20mg／dm3∑NH＋4（NH3）－N（010mg／dm3NH3－N），更为稳妥的安全含量为0．20mg／dm3∑NH＋4（NH3）－N（0．017mg／dm3NH3－N）。

The toxic test of ammonia to Penaeus penicillatus larvae in each stage showed that zoea larvae were the most sensitive to ammonia and the tolerence of postlarvae was the highest. At a salinity of 32,a pH of 8. 20 and a water temperature of 29. 0℃,the 24h LC50 values of nauplius (N3),zoea (Z1 ),mysis (M1 ) and postlarvae (P5) were 13. 20(1. 15), 9. 97 (0. 87 ),26. 99 (2. 35) and 60. 81 mg/dm3∑NH+4 (NH3)-N (5. 30mg/dm3NH3-N) [∑2NH+4 (NH3)-N indicates total ammonia as nitrogen (referring to NHt+4-N plus NH3-N)],respectively. The 48h LC50 of Z1, M1, P5 were 5. 21 (0. 45), 14. 86 (1. 29) and 32. 85mg/dm3∑NH+4 (NH3)-N (2. 86mg/dm3NH3-N), The 72h and 96h LC50 of P5 were 19. 62(1. 71 )and 11. 95 mg/dm3∑NH+4 (NH3)N (1. 04mg/dm3NH3-N). A 'safe level' of P. penicillatus larvae was 1. 20mg/dm3∑NH+4(NH3)-N (0. 10mg/dm3NH3-N ). A more conservative 'safe level' was 0. 20mg/dm3∑NH+4(NH3)-N (0. 017mg/dm3NH3-N).