235 Impact of yeast cell wall and probiotics on gut microbiota, immunity, and growth in weaned piglets

Abstract This study investigates the effect of yeast cell wall (YCW) supplementation and multispecies probiotics as alternatives to antibiotic growth promoters (AGPs) on the gut microbiota, immune function, and growth performance in weaned piglets. We utilized a randomized complete block design involving 160 piglets across four treatments during the nursery phase. The treatments administered throughout the experimental period were as follows: CONT+ = basal diet with Halquinol (AGP); YCW = basal diet with Saccharomyces cerevisiae yeast cell wall at 1 kg/MT; SIM+ = basal diet with YCW at 0.5 kg/MT + multispecies probiotic (Bacillus subtilis 2.0 x 10^9 CFU/g, Bacillus coagulans 5.0 x 10^8 CFU/g, Clostridium butyricum 5.0 x 10^7 CFU/g, and Bacillus licheniformis 2.0 x 10^9 CFU/g) at 0.6 kg/MT; SIM- = basal diet with YCW at 0.5 kg/MT + multispecies probiotic at 0.3 kg/MT. Methodologies include daily feed intake, body weight gain measurement, feed conversion ratio (FCR), diarrhea scoring, serum cytokine and chemokine concentration, and microbiome analysis. Throughout the study period (21 to 63 d), only FCR showed differences (P = 0.0076). CONT+ and YCW demonstrated better FCRs, at 1.543 and 1.585 respectively, without significant variation between them, while SIM- lagged with the least favorable outcome at 1.654 (Table 1). At 35 d, IL-10 concentrations were greatest in the SIM- group, showing a 271.25% increase compared with other treatments (Figure 2). At 49 d, IL-8 was least in the YCW group, with a 247% reduction compared with CONT+, while SIM+ and SIM- showed no significant differences compared with other treatments (Figure 1). The Firmicutes/Bacteroidota (F/B) ratio shows that the CONT+ treatment was inferior compared with the YCW, SIM+, and SIM- treatments (Figure 3). The Lactobacillaceae family differed between CONT+ and the YCW, SIM+, and SIM- treatments, with the greatest abundance in the SIM+ treatment, followed by SIM- and YCW (Figure 4). The genera Lactobacillus differed between the CONT+ treatment compared with the YCW, SIM+, and SIM- treatments. Prebiotics, whether used alone or combined with probiotics, serve as effective substitutes for AGPs, boosting the health and performance of piglets throughout the nursery phase.