Abstract
Total oxygen consumption, glycogen content and succinic dehydrogenase levels in liver, muscle and heart in normal and thiodon-exposed (to sub-lethal concentration of 48 h and to lethal concentration for 6 h) Sarotherodon mossambicus (Peters) were studied. While oxygen consumption of the fish dropped to 43 and 35% respectively under sub-lethal and lethal exposures, the magnitude of decrease in tissue glycogen content as well as tissue succinic dehydrogenase level followed a uniform order of liver > muscle > heart in both the exposures. Reduction in oxygen uptake and tissue glycogen levels were indicative of the onset of hypoxia involving utilization of stored glycogen by the fish under thiodon exposure. The inhibition of succinic dehydrogenase levels in the 3 tissues of thiodon-exposed Sarotherodon mossambicus , while indicating the impairment of aerobic metabolism, is also suggestive of a shift from aerobic to anaerobic metabolism in the fish under pollution stress.