Please use this identifier to cite or link to this item: http://hdl.handle.net/1893/19649
Appears in Collections:Aquaculture Journal Articles
Peer Review Status: Refereed
Title: Light and feeding entrainment of the molecular circadian clock in a marine teleost (Sparus aurata)
Authors: Vera, LM
Negrini, Pietro
Zagatti, C
Frigato, Elena
Sanchez-Vazquez, F Javier
Contact Email: luisa.veraandujar@stir.ac.uk
Keywords: Central peripheral oscillators
clock genes
feeding entrainment
gilthead sea bream
locomotor activity
Sparus aurata
Issue Date: Jun-2013
Publisher: Informa Healthcare
Citation: Vera L, Negrini P, Zagatti C, Frigato E & Sanchez-Vazquez FJ (2013) Light and feeding entrainment of the molecular circadian clock in a marine teleost (Sparus aurata), Chronobiology International, 30 (5), pp. 649-661.
Abstract: Daily light and feeding cycles act as powerful synchronizers of circadian rhythmicity. Ultimately, these external cues entrain the expression of clock genes, which generate daily rhythmic behavioral and physiological responses in vertebrates. In the present study, we investigated clock genes in a marine teleost (gilthead sea bream). Partial cDNA sequences of key elements from both positive (Bmal1, Clock) and negative (Per2, Cry1) regulatory loops were cloned before studying how feeding time affects the daily rhythms of locomotor activity and clock gene expression in the central (brain) and peripheral (liver) oscillators. To this end, all fish were kept under a light-dark (LD) cycle and were divided into three experimental groups, depending on the time of their daily meal: mid-light (ML), mid-darkness (MD), or at random (RD) times. Finally, the existence of circadian control on gene expression was investigated in the absence of external cues (DD + RD). The behavioral results showed that seabream fed at ML or RD displayed a diurnal activity pattern (>91% of activity during the day), whereas fish fed at MD were nocturnal (89% of activity during the night). Moreover, seabream subjected to regular feeding cycles (ML and MD groups) showed food-anticipatory activity (FAA). Regardless of the mealtime, the daily rhythm of clock gene expression in the brain peaked close to the light-dark transition in the case of Bmal1 and Clock, and at the beginning of the light phase in the case of Per2 and Cry1, showing the existence of phase delay between the positive and negative elements of the molecular clock. In the liver, however, the acrophases of the daily rhythms differed depending on the feeding regime: the maximum expression of Bmal1 and Clock in the ML and RD groups was in antiphase to the expression pattern observed in the fish fed at MD. Under constant conditions (DD + RD), Per2 and Cry1 showed circadian rhythmicity in the brain, whereas Bmal1, Clock, and Per2 did in the liver. Our results indicate that the seabream clock gene expression is endogenously controlled and in liver it is strongly entrained by food signals, rather than by the LD cycle, and that scheduled feeding can shift the phase of the daily rhythm of clock gene expression in a peripheral organ (liver) without changing the phase of these rhythms in a central oscillator (brain), suggesting uncoupling of the light-entrainable oscillator (LEO) from the food-entrainable oscillator (FEO). These findings provide the basis and new tools for improving our knowledge of the circadian system and entraining pathways of this fish species, which is of great interest for the Mediterranean aquaculture.
Type: Journal Article
URI: http://hdl.handle.net/1893/19649
DOI Link: http://dx.doi.org/10.3109/07420528.2013.775143
Rights: The publisher does not allow this work to be made publicly available in this Repository. Please use the Request a Copy feature at the foot of the Repository record to request a copy directly from the author. You can only request a copy if you wish to use this work for your own research or private study.
Affiliation: Aquaculture
University of Ferrara
University of Ferrara
University of Ferrara
University of Murcia

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