Effect of postweaning feed intake on performance, intestinal morphology, and the probability of diarrhoea in piglets.

Changes in gastrointestinal architecture, high incidence of diarrhoea, and low feed intake (FI) are commonly observed around weaning of pigs, but the relationship between postweaning FI and diarrhoea is unclear. This study aimed to determine the effect of low or high FI during the first days after weaning on growth performance, diarrhoea probability, intestinal permeability, and morphology in pigs until postweaning day (PWD) 28. A total of 120 pigs (7.20 ± 0.26 kg) weaned at 28 days of age (PWD 0) were randomly allocated to five diets and housed individually until PWD 28. Two diets differed in CP and three diets differed in threonine and tryptophan levels. At PWD 4, pigs with the 25% lowest accumulated FI (LOW; n = 30) and 25% highest accumulated FI (HIGH; n = 30) were selected for the study. Faecal consistency was evaluated daily using a 4-scale visual scoring system. Blood was collected at PWD 4, 14, 21 and 28, and small intestinal and colonic tissue was obtained at slaughter on PWD 28. Until PWD 4, LOW pigs consumed approximately 20% (35.7 ± 5.9 g/day) of the FI of HIGH pigs (181 ± 5.75 g/day; P < 0.05) and their average daily gain (ADG) was -103 ± 15.1 g/day. At PWD 28, average daily feed intake, ADG, and feed conversion ratio were still negatively affected by the FI level (P < 0.05) and pigs in the LOW group were on average 4.4 kg lighter than HIGH pigs. Pigs in the HIGH group showed a 55% higher probability of diarrhoea compared with LOW pigs during PWD 0-28. The number of antibiotic treatment days against diarrhoea was 2.38 days higher for HIGH compared with LOW pigs (P = 0.04). The intestinal permeability markers diamine oxidase and D-lactate in plasma were unaffected by the level of FI (P > 0.10). The systemic inflammatory markers haptoglobin and C-reactive protein were higher for HIGH pigs at PWD 4 (P = 0.005), but not affected in the following periods (P > 0.10). Pigs in the HIGH group had an increased area of acidic mucin-producing cells in the small intestine compared with LOW pigs (P < 0.05), but other intestinal morphology measurements at PWD 28 were unaffected by the level of FI. In conclusion, high FI just after weaning was associated with higher growth performance but also higher probability of diarrhoea and more frequent use of antibiotics until PWD 28.

Age-dependent development in protein digestibility and intestinal morphology in weaned pigs fed different protein sources.

Today, weaner diets are optimised using digestibility coefficients obtained from grower-finisher pigs, which may overestimate the digestibility in weaners. The aim of this study was to evaluate the standardised ileal digestibility (SID) of CP and amino acids (AAs), and the intestinal morphology in pigs 0-4 weeks postweaning when fed different protein sources. The experiment included 128 pigs weaned at day 28 and the protein sources were wheat, soybean meal (SBM), enzyme-treated soybean meal (ESBM), hydrothermally treated rapeseed meal (HRSM) and casein. The experiment was conducted as a difference method study including wheat in all diets. Eight pigs were slaughtered on the day of weaning (day 0) and six pigs/treatment were slaughtered at days 7, 14, 21, and 28 postweaning. The SID of CP and AA, as average over the four weeks, was lowest for ESBM and highest for wheat and casein, with SBM and HRSM being intermediate. The SID of CP and AA increased (both linear and quadratic, P < 0.05) over time after weaning. The average SID of CP for all protein sources postweaning was 0.38, 0.59, 0.76, and 0.71 on days 7, 14, 21, and 28, respectively. These differences were significant (P < 0.05) between days 7 and 21, and between days 7 and 28 (P < 0.05), whereas there tended to be a difference between days 7 and 14 (P = 0.06). Protein source did not affect the small intestinal morphology response parameters, whereas time after weaning did. Villous height and villous height to crypt depth ratio differed (P < 0.05) between the days 0 and 7, with shorter villi and a higher ratio at day 7. Crypt depth was not altered between days 0 and 7, or between days 7 and 14. For villi density, crypt density and small intestinal length, a significant increase from days 7 to 14 was observed, but there was no further increase to or difference between days 21 and 28. In conclusion, the low SID of CP in casein on day 7 (0.50) illustrates the challenges related to protein digestion in weanling pigs. The SID of CP and AA is very low during the first two weeks postweaning and time after weaning is more important for protein digestibility, than the source of protein. Fewer mature epithelial cells and less absorptive area in the small intestine in the early postweaning period may partly explain the poor protein digestibility.