Dietary Yeast Cell Wall Improves Growth Performance and Prevents of Diarrhea of Weaned Pigs by Enhancing Gut Health and Anti-Inflammatory Immune Responses

SIMPLE SUMMARY: Post-weaning stress can substantially affect performance of weaned pigs as well as overall pig production, and thus, a practical approach is needed to improve their performance by alleviating the stress that can cause intestinal barrier dysfunction of weaned pigs. There are potential ways to solve the concern in swine production, but dietary yeast cell wall in weaner diets may be one possible solution. The results of the present study suggest that dietary yeast cell wall improves growth performance of weaned pigs by enhancing gut health and provide its potential mechanism. ABSTRACT: Dietary yeast cell wall products (YCW) are recognized as a feed additive due to multifunctional benefits by the biological response modulators. Thus, this study was conducted to verify a potential advantage of YCW for improving growth performance, nutrient digestibility, immune responses, and intestinal health and microbiota of weaned pigs. A total of 112 weaned pigs (7.99 ± 1.10 kg of body weight; 28 days old) were arbitrarily allocated to two experimental treatments with eight pigs (four barrows and four gilts) per pen and seven replicate pens per treatment in a completely randomized block design (block = BW and sex): (1) a basal diet based on corn and soybean meal (CON) and (2) CON + 0.05% YCW. The experimental period was for 4 weeks. There were no differences in final body weight, average daily feed intake, and gain-to-feed ratio between dietary treatments. In contrast, pigs fed YCW had higher average daily gain (p = 0.088) and apparent ileal digestibility of DM (p < 0.05) and energy (p = 0.052) and lower diarrhea frequency (p = 0.083) than those fed control diet (CON). Pigs fed YCW also had a higher (p < 0.05) ratio between villus height and crypt depth, villus width and area, and goblet cell counts in the duodenum and/or jejunum than those fed CON. Dietary YCW decreased (p < 0.05) serum TNF-α and IL–1β of weaned pigs on day 7 and 14, respectively, compared with CON. Furthermore, pigs fed YCW had higher (p < 0.05) ileal gene expression of claudin family, occludin, MUC1, INF-γ, and IL-6 and lower (p < 0.05) that of TNF-α than those fed CON. Lastly, there were no differences in the relative abundance of bacteria at the phylum level between CON and YCW. However, dietary YCW increased (p < 0.05) the relative abundance of genera Prevotella and Roseburia compared with CON. This study provided that dietary YCW improved growth rate, nutritional digestibility, and intestinal health and modified immune responses and intestinal microbiota of weaned pigs.