Impact of temporal food restriction on sleep behavior and physiology of redheaded bunting

Abstract

Photic cues are the epicenter of regulating different biological rhythms, however non-photic cues like food and temperature also play a pivotal role in governing the same. The present study investigated the role of temporal food restriction on sleep behavior and physiology of redheaded bunting. Birds (N = 20 each for male and female) were divided into four groups on the basis of availability of food; group I (ad-libitum food; Control), group II (evening restriction group; ER), group III (morning restriction group; MR) and group IV (unpredictable group; UR). The food restricted groups showed starvation induced hyperactivity which influenced the temporal orientation of different sleep behaviors during night. Morning food restricted group showed abundance of back sleep, irrespective of sex. However, sleep duration was found unmoved by the restriction protocol. Morning food restriction significantly reduced body mass, food intake and liver weight in male birds, but females were found unresponsive to these changes. To understand the molecular underpinning of the physiological response, we checked relative mRNA expression of npy and vip in gut and hypothalamus of birds. npy expression was found elevated with respect to food restriction both in gut and hypothalamus. Moreover, hypothalamic nos1 and chrm3 were also evaluated as markers of sleep and wakefulness respectively. Food restriction resulted in elevated expression of chrm3 when compared with control. Thus, the present study highlights the role of temporal food restriction on sleep behavior and physiology of birds.