open access

https://hdl.handle.net/2115/39881

In vivo and in vitro effects of Rhizopus extract on body growth and steroid production in masu salmon, Oncorhynchus masou Brevoort

In vivo and in vitro effects of Rhizopus extract (RU) on body growth and steroid production in masu salmon, Oncorhynchus masou Brevoort

英語

masu salmon

2007-05

Blackwell Publishing

Aquaculture Research

38(7)

708-717

This study investigated in vivo and in vitro effects of Rhizopus (filamentous fungus) extract (RU) in masu salmon Oncorhynchus masou Brevoort. Underyearling fish were fed with RU for 16 months. Monthly changes in body growth, gonadal maturation and serum levels of sex steroids were monitored. Gonads were also incubated at 0, 1, 10, 100 and 1000 μg RU mL^[-1] Leibovitz's L-15 medium for 18 h. Levels of steroids in serum and cultured medium were measured. It was determined that RU-fed immature and mature males, when compared to control groups, showed significantly higher body growth during spring, summer, and the spawning period. Similarly, immature RU-fed females showed significantly higher fork length and body weight in autumn, spring and summer. Furthermore, RU-fed males showed significantly higher levels of serum testosterone (T) and 11-ketotestosterone (11-KT) levels in pre-spawning season, and 17α,20β-dihydroxy-4-pregnen-3-one (DHP) in spawning season. In vitro RU incubation of gonads showed a dose-dependent and significant increase in T, 11-KT, estradiol-17β and DHP release in the medium. It appears that the causes of enhanced body growth and increased steroid production herein observed in salmonids are the physiologically active substances that may be contained in the mycelium of the fungus.

学術雑誌論文

Accepted Manuscript

The definitive version is available at www.blackwellsynergy.com

1355-557X

AA11033925