Explaining daily feeding patterns in pigs: modelling interaction between metabolic processes and circadian rhythm

Research output: Chapter in Book/Report/Conference proceedingAbstract


Growing pigs housed under conventional conditions typically show two feeding peaks during the day: a smaller peak of feed intake shortly after the onset of light and a larger peak before dark. Feeding behaviour is under control of metabolic processes and affected by circadian rhythms. How circadian rhythms and metabolic processes interact over the day and cause the observed feeding patterns is not understood. Understanding this could provide valuable
insights into feeding behaviour and the effect on growth and productivity under imposed conventional housing conditions. The aim of this study was to gain more understanding of the causation of feeding behaviour and to explain the observed daily feeding patterns with two peaks in pigs. We developed an agent-based model in Netlogo in which feeding behaviour over the day emerged from interactions between energy metabolism and circadian rhythms.
Energy metabolism included processing of feed in the gastrointestinal tract and signalling in the body about energy absorption and use in the short and in the long term. Circadian rhythms included signals affecting energy expenditure and storage via catabolic and anabolic pathways (e.g. levels of melatonin, leptin and cortisol). These processes affected hunger and satiation of an agent (pig), which caused feeding behaviour via a motivational decision model. After parameterisation, the typical feeding pattern in pigs with a smaller peak in the morning and larger peak in the afternoon emerged from the model. Varying the energy content in the diet affected the size of peaks, while varying the light period affected the duration of peaks (e.g. merging peaks into one peak under 24 h light). Emerging feeding patterns such as daily feed intake, meal frequency and feeding rate were tested by comparing them to those observed in empirical studies. The model explains how metabolic processes and circadian rhythms
affect the metabolic energy balance over the day and can cause these daily feeding patterns in pigs. Furthermore, the model shows that feed intake in the late afternoon is most optimal for growth. The developed model gives a better understanding of the pig’s motivation to feed and how feeding behaviour can affect growth and productivity of pigs. The model will be further developed to study the role of social interaction in the causation of feeding patterns in group-
housed pigs.
Original languageEnglish
Title of host publicationProceedings of the 50th Congress of the International Society for Applied Ethology
PublisherWageningen Academic Publishers
Publication statusPublished - 12 Jul 2016
Event50th Congress of the International Society for Applied Ethology - Edinburg, United Kingdom
Duration: 12 Jul 201615 Jul 2016


Conference50th Congress of the International Society for Applied Ethology
CountryUnited Kingdom

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