Variability in feed intake the first days following weaning impacts gastrointestinal tract development, feeding patterns, and growth performance in nursery pigs.

The present study investigated the effects of voluntary feed intake (FI) the first days after weaning on gastrointestinal development and protein fermentation the first week after weaning and growth performance and feeding patterns during the nursery phase. A total of 144 mixed-sex weaned pigs (24 ±â€…2 d old; 7.2 ±â€…0.8 kg body weight [BW]) were allocated to 12 pens with 12 pigs/pen. Each pen was equipped with an electronic feeding station for monitoring individual FI during a 40-d study. Pigs were classified based on their cumulative FI over the initial 3 d after weaning (FId1-3) being above or below their pen median FId1-3 (high = 919 ±â€…244 g or low = 507 ±â€…222 g FId1-3). Similarly, weaning BW classes (BW0; high = 7.72 ±â€…0.59 kg or low = 6.62 ±â€…0.88 kg BW) were created to study interactions with FId1-3. Two female pigs with either a high or a low FId1-3 per pen (n = 24) were selected for sampling at d6 and were used to study gastrointestinal development and fermentation products in the small intestine. Feeding patterns per day, FI, and growth performance were measured individually. Low FId1-3 pigs had lower (P < 0.05) daily FI during d0 to d8, d8 to d15, and d22 to d28, BW on d15, d22, d29, and d40, and average daily gain during d0 to d8, d22 to d29, and d29 to d40 compared to high FId1-3. High FId1-3 pigs increased (P < 0.05) the number of visits to the feeder between d1 to d13 and d31 to d35, and the time spent per visit only for d1 to d4 (P < 0.05). The daily rate of FI (g/min) was higher (P < 0.05) for High FId1-3 pigs on d6, d8, d9, and d10, and again several days later (d20 to d39). In addition, the high FId1-3 × high BW0 interaction improved daily FI during d18 to d40 compared to low FId1-3 × low BW0 class (P < 0.05). For the sampling on d6, low FId1-3 pigs had a lighter small intestine, colon, and pancreas, and reduced villi length, smaller villi surface area, and a lower number of goblet cells size in jejunum (P < 0.05), while concentrations of lactic acid, histamine, and cadaverine in small intestinal content were increased (P < 0.05). In conclusion, pigs with high FId1-3 became faster eaters with higher FI and growth rates toward the second half of the nursery, which was similar and additive for pigs with higher weaning BW. High FId1-3 was also associated with greater development of the gastrointestinal tract and a reduced protein fermentation 1-wk after weaning.

Poor adaptation to solid feed after weaning is often associated with a reduced digestive function and growth in nursery pigs. The reasons driving an early acceptance of feed and its consequences are still largely unknown. We investigated the effects of high and low feed intake between d1-3 after weaning on gastrointestinal development and morphometrics 1-wk after weaning and growth performance and feeding patterns in the nursery phase. The results showed that pigs with a high initial feed intake (increased number of visits to the feeder and time spent per visit early after weaning), consumed feed faster throughout the nursery resulting in higher intakes early and late in the nursery but not for the intermediate period. Higher weaning body weight was also associated with improved feed intake and growth from d17 onwards, which was an additional but independent effect of the early feed intake effect. Besides, pigs with high feed intake between d1 and d3 after weaning had heavier empty gastrointestinal organs, improved intestinal wall morphometrics, and reduced protein fermentation in the small intestine 1-wk after weaning.