Nr. Le Francois et al., Exposures to low-level ionizing radiation: Effects on biochemical and whole-body indices of growth in juvenile brook charr (Salvelinus fontinalis), J EXP ZOOL, 283(3), 1999, pp. 315-325
Exposure to ionizing radiation (IR) was used to alter gonadal growth in bro
ok charr (Salvelinus fontinalis). To evaluate the possible effects of low-l
evel doses of IR on future seawater adaptability of brook charr, the physio
logical state and growth performances of juvenile brook charr were examined
for 15 months. Four groups of fish were exposed to different experimental
doses of IR at the hatching stage: 0 (control), 6.2, 7.8, and 11.4 Gy. Grow
th in length and weight and condition factors of the irradiated groups were
initially impaired compared with the control. Differences in growth were o
bserved and were proportional to the irradiation dose. Initial growth delay
in the irradiated groups was followed by compensatory growth of sufficient
magnitude and duration that similar weights and lengths among all groups w
ere reached by the end of the growth trial. Changes in the concentration of
nucleic acids, protein, and water content were evaluated at three trimestr
ial intervals in the control and 11.4 Gy groups. DNA content was systematic
ally found to be higher in the irradiated groups compared with the control
(602.76 and 850.38 mu g/g wet tissue). No difference in protein content (mg
/g) in relation to fish weight was found between both groups during the fre
shwater growth period. Lipid analysis was performed on the final samples an
d was found to be significantly higher in the irradiated groups displaying
catch-up growth (8.2% and 11.4% wet weight). RNA/DNA, RNA/protein, and prot
ein/DNA were also calculated. (C) 1999 Wiley-Liss, Inc.