Effects of Photoperiod and Feeding Schedule on Diel Variations of Locomotor Activity, Cortisol, and Thyroxine in Goldfish
作者:
RichardE. Spieler,
TeresaA. Noeske,
期刊:
Transactions of the American Fisheries Society
(Taylor Available online 1984)
卷期:
Volume 113,
issue 4
页码: 528-539
ISSN:0002-8487
年代: 1984
DOI:10.1577/1548-8659(1984)113<528:EOPAFS>2.0.CO;2
出版商: Taylor & Francis Group
数据来源: Taylor
摘要:
Goldfish Carassius auratus held on a 14L:10D (14-hour-light:10-hour-dark) photoperiod and fed once daily at unscheduled times during light and darkness had a diurnal activity pattern beginning about light onset; this rhythm lasted at least 3 days when fish subsequently were held in constant light or constant darkness. When goldfish were fed once daily at scheduled times during a 12L:12D photoperiod (the schedule varying among treatments with respect to light and darkness), their activity was entrained by the feeding time, and the activity cycle persisted through 3–10 days of starvation. Serum-cortisol concentrations also were entrained by feeding regimen, peaking 0–6 (often 4) hours before feeding, and mean daily titers were unaffected by the time of day feeding occurred. Serum-thyroxine concentrations, in contrast, were entrained by photoperiod, though daily mean titers were affected by feeding time. Thus, feeding schedule, when it provides a consistent cue, overrides photoperiod to entrain cyclic goldfish activity and serum-cortisol variations–but not serum-thyroxine variations. This implicates a multioscillatory system in the temporal integration of goldfish with their environment. For study of some endocrine rhythms in fish, activity cycles may provide a better reference than photoperiod.
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