ACUTE EFFECT OF SUBLETHAL AMMONIA CONCENTRATIONS ON COMMON CARP (CYPRINUS-CARPIO L) .1. EFFECT OF AMMONIA ON ADRENALINE AND NORADRENALINE LEVELS IN DIFFERENT ORGANS

The primary stress effects of sublethal concentrations of ammonia on common carp were studied. The changes in adrenaline and noradrenaline levels in heart, muscles and gills were followed at two ammonia concentrations (1475 and 1646-mu-g NH3-Nl-1) during 96 h. The highest levels of adrenaline and noradrenaline were measured in the heart (1.50 +/- 0.15-mu-g g-1 adrenaline and 0.39 +/- 0.09-mu-g g-1 noradrenaline). Levels of catecholamines in muscle were 0.14 +/- 0.05-mu-g g-1 adrenaline and 0.05 +/- 0.02-mu-g g-1 noradrenaline. The lowest activities (0.07 +/- 0.004-mu-g g-1 adrenaline and 0.01 +/- 0.002-mu-g g-1 noradrenaline) were measured in gills. The effect of increasing ammonia concentrations (500-2000-mu-g NH3-N l-1) was characterised at two temperatures (15 and 20-degrees-C). A proportional increase in adrenaline and noradrenaline levels was found with time after intoxication and along with ammonia concentration. A negative effect of the lower temperature started to prevail at an ammonia concentration of about 1000-mu-g NH3-N l-1. The enhanced level of catecholamines in different organs of carp following NH3 treatment showed that NH3 could exert stress in fish.