Effect of salinity acclimation on oxygen consumption of juveniles of the white shrimp Litopenaeus vannamei

Abstract

The present study was undertaken to establish the effect of salinity and acclimation time on the oxygen consumption of juvenile white shrimp Litopenaeus vannamei through evaluation of the mechanisms involved in adjustments of respiratory metabolism during acclimation and the effects on the apparent heat increment (AHI). Four experiments were conducted to assess the effect of acclimation time on oxygen consumption of shrimp exposed to salinity changes between 30 parts per thousand to 5 parts per thousand. The effects of a change of salinity were recorded immediately in the first hour and 24 h after change. The results showed that L. vannamei juveniles are well adapted to tolerate salinity changes when they are subjected to sudden change in salinity or are acclimated to salinity change. The effect of salinity on the apparent heat-increment coefficient (AHI-%) in shrimp acclimated over time was also tested. The fasting and feeding oxygen consumptions were increased according to a reduction in salinity, with high values in 5 parts per thousand and lower values in 30 parts per thousand. Although at 15 parts per thousand salinity the animals require energy to maintain homeostasis, we believe the juveniles acclimated at that salinity could be more efficient than those acclimated at 5 parts per thousand or 30 parts per thousand salinity because in that salinity shrimp consumed 1.22 and 1.69 more food than that observed in shrimp acclimated at 30 parts per thousand and 5 parts per thousand, respectively, and without an excessive increase in the costs associated with AHI-%.