Effects of dietary and lighting conditions on diurnal locomotor activity and body temperature in microminipigs

Abstract

The effects of dietary and lighting conditions on diurnal rhythm of locomotor activity (LA) and body temperature (BT) using four adult male microminipigs were investigated. Different feeding times, diet and lighting conditions were applied sequentially for 3 weeks in each phase as follows: Phase I: Morning mealtime, normal diet, 12-h lights on; phase II: mealtime changed to afternoon; phase III: diet changed to high-fat diet; phase IV: lighting changed to 20-h on; and phase V: phase I repeated. LA was measured by an actigraph which was worn on the body of each pig. A BT recording module (Thermochron Type-SL) was implanted in the neck subcutaneously. Phase II increased BT compared with phase I. Phase III increased LA and BT compared with phase II. Phase IV increased LA compared with phase III. LA in phase V was higher compared with phase I. These results can be extrapolated to other diurnal animals such as humans. This study provides an example of the effects of diet and lighting on biological activities in microminipigs under low-invasive procedures measuring LA and BT, leading to low variations in these measures.