Reverse translation: effects of acclimation temperature and acute temperature challenges on oxygen consumption, diffusive water flux, net sodium loss rates, Q 10 values and mass scaling coefficients in the rainbow trout ( Oncorhynchus mykiss )

AbstractOur understanding is limited on how fish adjust the effective permeability of their branchial epithelium to ions and water while altering O2 uptake rate (MO2) with acute and chronic changes in temperature. We investigated the effects of acclimation temperature (8  °C, 13 °C and 18 °C) and acute temperature challenges [acute rise (acclimated at 8 °C, measured at 13 °C and 18 °C), acute drop (acclimated at 18 °C, measured at 8 °C and 13 °C) and intermediate (acclimated at 13 °C, measured at 8 °C and 18 °C)] on routine MO2, diffusive water flux, and net sodium loss rates in 24-h fasted rainbow trout (Oncorhynchus mykiss). In the temperature challenge tests, measurements were made during the first hour. In acclimated trout at all temperatures, allometric mass scaling coefficients were much higher for diffusive water flux than for MO2. Furthermore, the diffusive water flux rate was more responsive (overallQ10 = 2.75) compared to MO2 (Q10 = 1.80) over the 8–18 °C range, and for both,Q10 values were greater at 8 –13 °C than at 13–18 °C. The net Na+ flux rates were highly sensitive to acclimation temperature with an overallQ10 of 3.01 for 8 –18 °C. In contrast, very different patterns occurred in trout subjected to acute temperature challenges. The net Na+ flux rate was temperature-insensitive with aQ10 around 1.0. Both MO2 and diffusive water flux rates exhibited lowerQ10 values than for the acclimated rates in response to eith...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - Category: Physiology Source Type: research