Effects of a Glycosylated Form of Active Vitamin D Combined with Natural Triterpenes on Sow Productive Performance, Mineral Homeostasis, Immune Biomarkers and Serum Proteome

This study evaluated the effects of the dietary administration of a glycosylated form of active vitamin D (calcitriol, 1,25(OH)2D3) combined with ursolic acid (UA) and oleanolic acid (OA) triterpenes on sow health and productivity. Twenty-four third-parity Landrace × Large White sows were allocated at day 108 of gestation into three groups: a control group receiving 1800 IU/kg of vitamin D3, and two treatment groups receiving the control diet supplemented with either 0.64 µg/kg (ACTD1) or 0.96 µg/kg (ACTD2) of glycosylated 1,25(OH)2D3 plus 140 or 210 µg/kg of UA + OA (4:1 ratio), respectively. Diets were administered from late gestation through the end of lactation. Farrowing duration, sow bodyweight, backfat thickness, and litter growth were recorded. Blood samples collected at key physiological stages were analyzed for pro-inflammatory cytokines, mineral homeostasis, endocrine markers, and serum proteome. Farrowing time was reduced in both treatment groups compared with the control (p < 0.05). Treated sows exhibited lower backfat thickness at the end of lactation and improved litter weights at farrowing, after cross-fostering, and at weaning (p < 0.05). Plasma pro-inflammatory cytokines (TNF-α, IL-1α, and IL-1β) were reduced at the end of lactation in ACTD1 and ACTD2 sows, with TNF-α and IL-1β already decreased after farrowing (p < 0.05). Treated sows also displayed decreased plasma parathormone concentrations at the end of lactation, along with increased circulating 1,25(OH)2D3 and calcium concentrations after farrowing and at lactation end (p < 0.05), while plasma phosphate levels remained unchanged. Proteomic analysis supported the systemic availability of the supplemented compounds and their involvement in metabolic and inflammatory pathways rather than calcium transport or vitamin D binding mechanisms. Overall, this nutritional strategy influenced the immune modulation while maintaining mineral homeostasis via modest endocrine adaptations. Larger-scale trials are warranted to confirm these results and to evaluate their practical applicability under commercial production conditions.