Muscle metabolism of freshwater fish, Tilapia mossambica (Peters), during acute exposure and acclimation to sublethal acidic water

Abstract

Fresh water fish, Tilapia mossambica (Peters), were subjected to acute exposure and acclimation to sublethal acid water (pH 4.0), and the muscle metabolism was investigated. Differential patterns of carbohydrate metabolism were witnessed in the red and white muscles in response to both acute exposure and acclimation. The glycogen content of red muscle was elevated whereas that of white muscle was depleted on acute exposure. But on acclimation, both the muscles had elevated glycogen content. The red muscle seems to mobilize carbohydrates into both hexose mono- and di-phosphate pathways, but white muscle does so only into the hexose monophosphate pathway on acclimation. In general, both the muscles exhibited suppressed glycolysis and elevated oxidative phase leading to elevated glycogen level. The muscle metabolism was oriented towards conservation of carbohydrates and lesser production of organic acids on acclimation, as a possible metabolic adaptive mechanism of the fish, enabling them to counteract the imposed acid stress.