Evidence for an endogenous circadian rhythm of feeding in the trout (Oncorhynchus mykiss) |
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Authors: | E. M. Cuenca M. de la Higuera |
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Affiliation: | Dpto. de Biologia Animal, Fac. Ciencias , Universidad de Granada , Granada, E‐18071, Spain |
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Abstract: | Abstract The possible endogenous circadian rhythm in the feeding activity of rainbow trout (Oncorhynchus mykiss) was investigated using individual fish previously trained for self‐feeding. Under LD 12:12 conditions, the fish showed a diurnal behaviour, in many cases with a feeding rhythm with two main peaks of food demand at dawn and dusk, with an 8h interval of low feeding activity, and the actograms showed an expected 24 h rhythm. Fish kept under constant conditions (L : L, 15°±0.5°C), showed free‐running feeding activity for about 12 days. Food demands were concentrated at dawn, with a periodogram of 25.3 hour, under continuous environmental conditions. Results showed evidence for the endogenous origin of the circadian rhythm of feeding in this species. |
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Keywords: | Endogenous rhythm feeding rhythm trout meal timing |
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