Use of Anesthetics in Metabolism Studies With Penaeid Shrimps 



Zoula P. Zein-Eldin 



During the past 3 years, studies of oxygen consumption in two 

 species of Penaeus have enabled us to determine a standard rate of metab- 

 olism for each. Since differential physical activity in experimental animals 

 may be a major source of variability in the measurement of oxygen uptake, 

 the possibility that it might be eliminated by general anesthesis is being exam- 

 ined. For this purpose, the anesthetic should act rapidly, have an effective 

 period of at least 1 hour (to permit accurate respirometry), and be nontoxic. 

 Of the seven compounds tested (sodium pentabarbital, ethclorovynol, methyl- 

 parafynol, tribromoethanol, chlorobutanol, menthol, and M. S. 222), none 

 seem to meet all the above requirements at any given concentration. The 

 effective anesthetic dose for postlarval shrimp was found in all cases to be 

 at least 10 times greater than that for fish of comparable weight. Moreover, 

 there is a very narrow concentration range in which rapid sedation can be 

 obtained and maintained without fatality. Present tests are investigating the 

 feasibility of using a high initial concentration to induce sedation, followed 

 by a reduced maintenance dosage. 



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