301 Effect of the addition of fermented components with feed enzymes to pig diets on metabolic processes, including regulation of gut-brain axis activity.

Abstract The study examined the effects of 8% dried fermented rapeseed meal (FRSM) and feed enzymes on nutrient and amino acid digestibility in piglets, focusing on gut-brain axis regulation. A total of 288 Yorkshire × Danish Landrace piglets were assigned to three groups: a positive control (KP) with a standard diet and feed enzymes, a negative control (KN) with a basal diet without additives, and an experimental group (F) where soybean meal was replaced with 8% FRSM in the KN diet. Digestibility was assessed using 2 g SiO₂/kg as an indigestible marker. At 30 kg, six piglets per group were euthanised for ileal content analysis of apparent intestinal digestibility (AID) of nutrients, amino acids, and microbiological composition. Hippocampal samples were collected for mood-related protein marker analysis via SDS-PAGE and densitometry. AID of crude fiber (CF) and crude protein (CP) was similar in KP and F but significantly higher than in KN. Ile and Lys digestibility was greater in KP and F than in KN, with the highest AID values for Cys, Leu, Met, and Thr in F. Microbiological analysis showed KN had increased aerobic mesophilic bacteria and Clostridium perfringens in the colon compared to KP and F. Escherichia coli and coliform bacteria were most abundant in KN, while Lactobacillus spp. populations were similar across groups. In the ileum, Yersinia spp. was more prevalent in KN than KP, while Campylobacter spp. was higher in KN than KP and F. In the jejunum, E. coli and coliform counts peaked in KN, whereas the highest Lactobacillus spp. population was found in F. Hippocampal protein expression analysis revealed no significant differences in AMPK and mTOR. However, Akt and NGF were highest in F. BDNF was significantly upregulated in both F and KP compared to KN. TrkB was highest in F, while ERK kinase was elevated in F and KP. GSK increased in F but decreased in KP and KN. CAMK2 and CREB remained unchanged, while eEF2 and NMDA receptor expression were highest in F, suggesting potential neurobiological benefits for memory and learning. In conclusion, dietary FRSM improved nutrient digestibility, modulated gut microbiota, and enhanced neuroplasticity-related protein expression in piglets. These findings suggest FRSM could be a functional feed component, supporting metabolic and neurobiological functions in weaned piglets. Research conducted as part of the project “Support for Students in Enhancing Their Competencies and Skills” (Measure 01.05 Skills in Higher Education, European Funds for Social Development Program 2021-2027), initiated by the Ministry of Science and Higher Education.