Hydrolyzed Yeast Supplementation to Newly Weaned Piglets: Growth Performance, Gut Health, and Microbial Fermentation

Hydrolyzed yeast (HY)-derived protein from <i>Saccharomyces cerevisiae</i> has a high digestible protein content and nucleotides and is a sweetener immunostimulatory substance. This could be used in nursery diets to minimize diarrhea and improve the growth rate and gut health of early-weaned piglets. This research was conducted with the objective of examining the effect of the inclusion level of HY as a potential protein ingredient for early-weaned piglets. A total of 72 crossbred weaned piglets [(Landrace × Large White) × Duroc] were assigned to three dietary treatments in six replicates with four pigs per pen. Dietary treatments were: (i) control (CON), piglets weaned at 18 days; (ii) CON diet with 5% HY inclusion (HY5); and (iii) CON diet with 10% HY inclusion (HY10) in a corn–soybean meal-based basal diet. Increasing HY levels positively improved body weight, average daily gain, and average daily feed intake (linear effect, <i>p</i> < 0.05). Furthermore, there was a linear increase in N-retention, albumin, jejunal villus height, villus height-to-crypt depth ratio, immunoglobulin A, acetate and propionate production, and <i>Lactobacillus</i> spp. count proportional to the dose of the HY-supplemented diet (<i>p</i> < 0.05). It also observed a decrease in diarrheal rate, jejunal crypt depth, blood urea nitrogen, pro-inflammatory cytokines, branched amino acids, and <i>E. coli</i> corresponding to the HY-supplemented levels (<i>p</i> < 0.05). However, the changes in the apparent total tract digestibility (dry matter, crude ash, and crude fat), blood glucose, butyrate, and <i>Salmonella</i> spp. were unaffected by the dietary HY level. Therefore, the supplementation of HY in the diet for early-weaned pigs not only supported the growth rate and immune function but also activated the beneficial bacterial growth of the early-weaned piglets.