Stress-induced changes in concentrations of plasma sex steroids in black bream

• Published in: Journal of fish biology Vol. 55; no. 6; pp. 1304 - 1316
• Main Authors: HADDY, J. A, PANKHURST, N. W
• Format: Journal Article
• Language: English
• Published: Oxford Blackwell 01-12-1999
• Subjects: Acanthopagrus butcheri; Animal aquaculture; Animal productions; Biological and medical sciences; Freshwater; Fundamental and applied biological sciences. Psychology; Pisciculture; Vertebrate aquaculture; Confinement; Environmental factor; Wild animal; Concentration; Stress; Blood plasma; Freshwater environment; Vertebrata; Gonad; Pisces; Developmental stage; Steroidogenesis; Sex steroid hormone; Aquaculture
• ISSN: 0022-1112; 1095-8649
• DOI: 10.1006/jfbi.1999.1128

Cortisol levels of black bream Acanthopagrus butcheri at capture did not change with time of day, gonadal stage or season and were 1.9 plus or minus 0.2 and 2.8 plus or minus 0.4 ng ml super(-1)for male and female fish, respectively. Confinement resulted in significantly elevated cortisol levels at all time periods; however, levels after 24 h of confinement were significantly lower than peak cortisol levels (15 min for males and 1 h for females). Confinement stress resulted in reduced levels of 17 beta -oestradiol (E sub(2)) and testosterone (T) within 1 h in sexually mature females. In mature males, suppression of T and 11-ketotestosterone (11KT) occurred after 30 min and 6 h of confinement, respectively. The relationship between confinement stress and levels of 17,20 beta -dihydroxy-4-pregnen-3-one (17,20 beta P) was more complex, with levels in males being elevated after 15 min and 24 h and suppressed after 6 h of confinement. In contrast, 17,20 beta P levels in females were elevated after 1 h of confinement. In regressed females, plasma E sub(2)and T concentrations were low at capture and were not affected by confinement stress whereas plasma 17,20 beta P was elevated within 1 h. This study indicates that stress exerts a rapid inhibitory effect on gonadal steroidogenesis.