Premium
The effects of extremely alkaline water (pH 9·5) on rainbow trout gill function and morphology
Author(s) -
Wilkie M. P.,
Wood C. M.
Publication year - 1994
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/j.1095-8649.1994.tb01288.x
Subject(s) - zoology , rainbow trout , sodium , biology , excretion , trout , ammonia , amiloride , chloride , nuclear chemistry , medicine , fish <actinopterygii> , endocrinology , chemistry , biochemistry , fishery , organic chemistry
Rainbow trout that were held under control conditions, at pH8·0, in moderately hard Hamilton tap water, had Cl − and Na + influx rates ( J CL in and J Na , respectively) of 270 and 300 μmol kg −1 h −1 , respectively. Exposure to pH 9·5 water led to an immediate 67% decline in J CL in and a 45% reduction in J Na in at 0–1 h. Influx rates declined further and by 4–5 h the net decreases in both J CL in and J Na in approximated 80%. By 24 h J CL in had recovered to rates not significantly different from those at pH 8·0; while J Na in only partially recovered and remained about 50% lower than control measurements through 72 h. The complete recovery of J CL in and partial recovery of J Na in may have been related to a fourfold greater branchial chloride cell (CC) fractional surface area observed in rainbow trout exposed to pH 9·5 for 72 h. Ammonia excretion ( J Amm ) was about 170 μmol N kg −1 h −1 at pH 8·0 but was initially reduced by 90% over the first hour of high pH exposure. J Amm rapidly recovered and by 24 h it had returned to pre‐exposure levels. This recovery tended to parallel the partial recovery of J Na in . However, subsequent addition of amiloride (10 −4 M) to the water at 75 h led to no change in J Amm , despite a 50% reduction in J Na in . Thus, it does not appear that there is a linkage between Na + influx and the recovery of ammonia excretion under highly alkaline conditions.