Physiological and metabolic adaptations to different photoperiods: effects of obesity and seasonal fruit consumption

Identifier:  TDX:2858

Handle: https://hdl.handle.net/20.500.11797/TDX2858

Authors:  Mariné Casadó, Roger

Abstract:
Through evolutionary history, the coexistence of animals and plants have led to the development of an adaptive phenomenon that has been recently explained by the xenohormesis theory. This theory postulates that the phytochemicals synthesized by stressed plants could be recognized as signals by the heterotrophs that consume them, being informed about the external conditions in which plants were harvested and allowing them to favorably adapt to unpredictable changes in the environment. Thus, each plant contains a distinctive phytochemical composition informing about the environmental status. In this framework, the main aim of the present thesis was to evaluate whether fruit consumption out of season would induce an erroneous signaling, leading to detrimental effects on physiology and metabolism of normoweight and cafeteria-fed obese Fischer 344 rats, by analyzing glucose and lipid metabolism-related parameters in blood, liver and skeletal muscle. To achieve this objective, we firstly characterized the physiological and metabolic adaptations to the chronic exposure to different photoperiods, which resembled seasonal variations in day length, in normoweight and obesogenic conditions. Once characterized, we evaluated the effects of the consumption of sweet cherry, a popular anthocyanin-rich fruit harvested in spring/summer, in short and long photoperiods resembling winter and summer, respectively. Firstly, we reported that the chronic exposure to different photoperiods induces several variations in physiological and metabolic parameters in normoweight and diet-induced obese rats, mainly affecting glucose and lipid metabolism and insulin signaling. Secondly, we revealed that cherry intake induces marked photoperiod-dependent effects, promoting more pronounced and, to some extent, more negative effects concerning glucose metabolism and insulin signaling in normoweight and diet-induced obese F344 rats when it was consumed out of season. These findings could contribute to highlighting the importance of the consumption of seasonal fruits to maintain an optimal health.