In vitro screening of the effects of ruminant colostrum source and processing on intestinal health and caecal fermentation under simulated post-weaning conditions in piglets

Weaning represents a major challenge for piglets, often impairing intestinal function and hindgut fermentation. This exploratory in vitro study evaluated the dietary supplementation with ovine colostrum (OC), bovine colostrum (BC), and reconstituted bovine colostrum (RBC) at 4 or 20 mL/L against the control (CTL), using complementary models simulating post-weaning conditions. Intestinal health was assessed in Caco-2 monolayers, and caecal fermentation in batch cultures inoculated with caecal contents from weaned piglets. Colostrum fractions (whole, defatted, IgG-depleted and proteins-depleted) were evaluated to identify which fractions were involved in the observed responses. Whole colostrum did not affect the mitochondrial dehydrogenase nor malondialdehyde concentrations in Caco-2 cells, used as indicators of cytotoxicity and oxidative stress respectively, but increased the pro-inflammatory IL-6. Fractions retaining medium- and low-molecular-weight compounds reduced oxidative stress by up to 59% (p < 0.05). Whole RBC enhanced caecal fermentation dose-dependently, with the high dose increasing gas production (+22%, p < 0.001), VFA (+28%, p = 0.005), and ammonia–N concentrations (+83%, p < 0.001), reflecting greater nutrient supply, whereas the low dose increased VFA production per unit of substrate (+24%, p = 0.013). Defatting retained positive effects on hindgut fermentation, while further fractionation reduced gas and VFA production per unit of substrate. Overall, colostrum supplementation modified intestinal health markers in Caco-2 cells and increased in vitro caecal gas production, total VFA and ammonia-N concentrations, with responses varying according to fraction and dose. These preliminary findings support further investigation of colostrum fractionation and require in vivo validation.