Impact of liquid diet supplementation while suckling and weaning age on nutritional status, intestinal health, and immunity of piglets pre- and post-weaning.

New strategies are needed to enhance piglets' robustness and proper functional development and maturation of piglets' intestine before weaning, to reduce the number of antibiotic treatments of diarrheic disorders in newly weaned piglets. It was hypothesized that a liquid nutritional supplement during the suckling period, and/or an increased weaning age, would beneficially impact piglets' gut health and enhance piglets' nutritional status before weaning. Further, it was hypothesized that a high intake of colostrum during the first 24 h after birth would be more advantageous for piglets' growth and robustness when compared to a low colostrum intake (CI). A 2 × 2 factorial design with two nutritional strategies (± supplementation with milk/feed, i.e., milk provided from day 2 shifted to wet feed at day 12 of age) and two weaning ages (days 24 vs. 35) was used. In total, 460 piglets from 24 sows were used for estimation of the individual CI after birth. Provision of the nutritional supplement and the increased weaning age improved the nutritional status of piglets' post-weaning assessed by their blood plasma concentration of albumin (P = 0.04), triglycerides (P = 0.004), and nonesterified fatty acids (P = 0.02). Piglets with high CI demonstrated improved nutritional status when compared to low CI (P = 0.04). Villous height and crypt depth were greater in piglets weaned at day 35 of age in contrast to day 24 of age (P < 0.001) irrespective of the nutritional intervention (P = 0.82). The concentration of branched-chain fatty acids in piglets' digesta was reduced in groups provided the nutritional supplement (P = 0.01), while total short-chain fatty acids were elevated at weaning in large intestinal digesta of piglets weaned at day 35 of age compared to piglets weaned at day 24 of age (P = 0.05). The weaning age in combination with the nutritional supplement had pronounced beneficial effect on gene expression of all investigated genes: interleukin-6, interleukin-10, nuclear factor kappa-beta, occludine, prostaglandin-endoperoxide synthase-2, tumor necrosis factor-alpha, and zonula occludens-1 (ZO-1) (P = 0.04). In conclusion, nutritional supplementation preweaning combined with increased weaning age could be considered as a strategy for improvement of the intestinal health, function, and maturation in piglets pre- and post-weaning, and a high CI enhanced piglets' robustness before weaning.