Effect of selection for residual feed intake on feeding behavior and daily feed intake patterns in Yorkshire swine1

Abstract

Residual feed intake (RFI) is a measure of feed efficiency defined as the difference between observed and predicted feed intake based on average requirements for growth and maintenance. The objective of this study was to evaluate the effect of selection for decreased RFI on feeding behavior traits and to estimate their relationships with RFI. Three data sets from the 4th and 5th generations of a selection experiment with a line selected for reduced RFI (LRFI) and a randomly selected control line (CTRL) were analyzed. Lines were mixed in pens of 16 and evaluated for feeding behavior traits obtained from a single-space electronic feeder over a growing period of ~3 mo before ~115 kg. The following traits were evaluated as averages over the entire test period and over the first and second half of the test period: number of visits per day and hour; occupation time per day, visit, and hour; feed intake (FI) per day, visit, and hour; and FI rate per visit. Models used included fixed effects of line and feeder, covariates of on-test age and FI per day, and random effects of pen, on-test group, sire, and litter. Repeated measures models were used to analyze feeding patterns during the day. The LRFI pigs had significantly less FI per day than CTRL pigs for all 3 data sets. With adjustment for FI per day, line differences of all traits were in the same direction for all 3 data sets but differed in significance and size. Feed intake per visit and hour and visits per day and hour did not differ between lines, but the trend was for LRFI pigs to have fewer visits, in particular during peak eating times. The LRFI pigs had a greater feeding rate and less occupation time per day, visit, and hour than CTRL pigs, but this was not significant for all data sets. Correlations of RFI with FI per day and visit and visits per day were positive. Average daily gain was positively correlated with FI per day and visit and occupation time per visit but negatively correlated with visits per day. Feed intake per day was positively correlated with backfat. In conclusion, feed efficiency may be affected by FI behavior because selection for decreased RFI has resulted in pigs that spend less time eating and eat faster.

Pigs that are divergent in feed efficiency, differ in intestinal enzyme and nutrient transporter gene expression, nutrient digestibility and microbial activity

“…The RFI value found in this experiment of −140 g/day is in line with previous experiments proving that the pigs in this study are a population of pigs divergent in RFI (Young and Dekkers, 2012). In contrast to previous RFI studies (Young et al, 2011;Mani et al, 2013;Montagne et al, 2014) backfat was not included in the model in this study. However, Do et al (2014) established a correlation coefficient of 0.96 between models with or without backfat, suggesting that the non-inclusion of backfat in this study will not unduly influence the results.…”

Influence of sex and immunocastration on feed intake behavior, skatole and indole concentrations in adipose tissue of pigs

“…In contrast, in a study with growing Yorkshire pigs selected for differences in residual feed intake, a similar bimodal pattern as was only found for the number of visits/2-h block along the day, but not for occupation time, was seen, which was constantly high between 1200 and 2000 h (Young et al, 2010). No sex differences or treatment differences were obvious in the diurnal pattern, but pronounced differences in feed intake behavior along the fattening period occurred.…”

Divergent selection for residual feed intake in group-housed growing pigs: characteristics of physical and behavioural activity according to line and sex

“…Our results also suggest that low RFI is associated with shorter daily eating time and lower number of meals, in agreement with a larger study on these RFI lines at earlier stages of selection (Gilbert et al, 2009). In purebred Yorkshire pigs, Young et al (2011) reported no significant difference in feeding patterns between a low RFI line compared with a control line after five generations of selection, but a trend for low RFI to visit the SEF fewer times and to spend less time eating per visit. In our study, the line difference on feed intake and visit duration was larger at the end of the growing period, as given in the study by Gilbert et al (2009).…”

“…In pigs, some studies have focused on relationships between RFI and appetite and feeding activity (De Haer et al, 1993;Rauw et al, 2006;Gilbert et al, 2009;Young et al, 2011). They indicate that decreased RFI is † E-mail: marie-christine.salaun@rennes.inra.fr Animal (2014), 8:11, pp 1898-1906 animal 1898 related to diminished daily feed intake (DFI), feeding patterns characterized by fewer meals, less time eating per day and a higher feeding rate.…”