Elucidating the Impact of Feeding Behaviour on Body Composition in Finishing Pigs Fed Ad Libitum Using an Integrative Feeding Behaviour Index

Abstract Large variability in body composition is observed in pigs fed and raised in similar conditions. Part of this variation might be explained by the feeding behaviour of pigs, given its effect on metabolic hormones associated with energy regulation and protein metabolism. The objective of this study was to elucidate this relationship by examining body composition with a new index describing feeding behaviour in finishing pigs. Feeding behaviour and body composition information on 138 pigs during the last 28 d of the finishing phase from three trials were used. For each pig, the sum of the areas between the observed relative cumulative feed intake and the regression line for the evolution of relative feed intake over time was used to calculate the new feeding behaviour index. This index quantifies the irregularity of feed intake (IIFI) by integrating different components of feeding behaviour into a single measurement. Body lipids and protein composition were estimated by dual X-ray densitometry at the beginning (day 1) and end of the finishing phase (day 28). The relationship of IIFI with performance and body composition variables was examined using correlation tests and factor analysis within each dataset. In datasets where IIFI was correlated with body composition, linear models were used to quantify the contribution of IIFI to the total variation of body composition. Weak to moderate correlations (r = ±0.31 to ±0.44; P