Effects of water-borne 4-nonylphenol and 17�-estradiol exposures during parr-smolt transformation on growth and plasma

• Main Authors: J. T. M. Arsenault A, W. L. Fairchild A, D. L. Maclatchy B, L. Burridge C, K. Haya C, S. B. Brown D
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2003
• Subjects: Atlantic salmon; Salmo salar
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.336.7801; http://www.gulfofmaine.org/kb/files/8930/ArsenaultEtAl04.pdf

4-Nonylphenol (4-NP) is an endocrine disrupting substance (EDS) capable of mimicking the action of 17�-estradiol (E2). It has been hypothesized that 4-NP in a pesticide formulation is linked to historical declines in Canadian Atlantic salmon (Salmo salar L.) populations, with effects being related to exposure during parr-smolt transformation (PST). To test this hypothesis, Atlantic salmon smolts were exposed to pulse-doses of water-borne 4-NP (20 ug/l), sustained doses of water-borne E2 (100 ng/l) (positive control), or ethanol vehicle (negative control) in mid-May during the final stages of PST. Individually tagged smolts were then sampled at three times (June, July and October) to monitor subsequent growth in sea water and plasma insulin-like growth factor I (IGF-I) concentrations. Smolt weights and plasma IGF-I concentrations were both affected by E2 and 4-NP. The effects of E2 and 4-NP on mean smolt weights were most prominent in July and October {E2 ( ∗ 98.1 ± 2.8, ∗ 242.3 ± 10.6 g), 4-NP ( ∗ 102.1 ± 3.1, 255.7 ± 9.5 g), controls (112.5 ± 2.8, 282.3 ± 8.8g)} (P <0.05), while their effects on mean plasma IGF-I concentrations were most prominent in June and October {E2 (15.0±1.9, 28.4±1.8 ng/ml), 4-NP ( ∗ 14.8±1.9, ∗ 21.6±1.7 ng/ml), controls (20.0 ± 1.1, 31.1 ± 2.0 ng/ml)} (P <0.05). Additionally, results suggest that the mechanisms of action of E2 and 4-NP involve disruption in the GH/IGF-I axis, and that they may be different from each other. The effects of E2 and 4-NP on growth and plasma IGF-I concentrations observed in this study are ecologically significant because they evoke concerns for successful