A pilot study testing a continuous glucose monitoring sensor in lean growing pigs fed contrasting diets, to document nocturnal and diurnal glycemic excursions as well as their relationships

• Wearable glycemic sensors are informative in lean growing pigs • There is a large inter-individual variability in diurnal glycemic excursions • Nocturnal glycemia fluctuates with both nadirs and peaks of glucose concentrations • Nocturnal glycemic wavelets are influenced by diet composition • Nocturnal glycemia events may predict glycemic responses to the first morning meal Timely non-invasive monitoring of physiology is an emerging field in farm animal research, providing new insights on how animals adapt to environmental challenges and how we can manage performance, health, and welfare. In this study, continuous glucose monitoring (CGM) sensors were used to document glycemic excursions in lean growing pigs. Crossbred pigs (49 ± 3 kg, n = 8) were fitted with CGM sensors and indwelling venous catheters, and followed in a five-day feeding trial involving a progressive change in diet composition from high starch (HS) to high fat (HF). At days 2 and 5, time-series blood samples were collected after the first morning meal and used for time-matched chemistry analysis. During the postprandial period, the average CGM reading was higher (P = 0.01) on the HS diet than on the HF diet, primarily due to the fact that maximum glucose value at peak was higher (P < 0.05) after consuming the HS test meal than the HF meal. During night when the pigs had no access to feed, the period with glucose concentrations above baseline was twice longer (P < 0.05) with the HS diet than the HF diet. Various CGM metrics at night were or tended to be correlated with postprandial CGM metrics (P < 0.10). Finally, large inter-individual variability was observed in glycemic metrics, larger during day than during the night (P < 0.05). To conclude, this study highlights the importance of considering night-time events to inform about animal physiology and further improve precision feeding in pigs.