Respiration of Artemia franciscana cultured under different salinities

Abstract

AbstractThe available studies on oxygen consumption by Artemia related to different salinities reported contradictory results. However, most of these studies have been obtained only for newly hatched nauplii or adults, and have neglected the gradual accommodation that gives a picture about what really happens in nature. In order to face the problems noted above individuals of Artemia franciscana were acclimated to four different salinities (25 g/L, 35 g/L, 70 g/L and 120 g/L) under laboratory conditions. The oxygen consumption under declining oxygen tensions (Po 2) for each of the 19 stages in Artemia life metamorphic developments was examined. The brine shrimp under different salinities is a respiratory regulator over a wide range of Po 2's. Oxygen consumption rates varied across the salinities with a general inverse relationship in uptake rates versus salinity. The brine shrimps' individual weight significantly decreased with increasing salt concentration of the external medium. Generally, regulation of oxygen consumption improved with development. Specimens cultured under high salinities (70 g/L and 120 g/L) started the regulation earlier than low salinities, even before heart and gill formation (in stage 2) and high salinities also accelerated the development of the heart and the gut earlier than those cultured under lower salinities (stage 3 instead of 6). Later developmental stages did not perform osmotical work in the same manner as nauplii did (0-6) and oxygen consumption did not drive the ionic regulation of Artemia franciscana specimens cultured under different salinities.