Effects of dietary barley malt extract on growth performance, immune parameters, intestinal fermentation and gut microbiota in nursery piglets

This study evaluated the effects of graded dietary barley malt extract (BME) supplementation on growth performance, fecal consistency, immune parameters, antioxidant status, short-chain fatty acid (SCFA) concentrations, and gut microbiota composition in nursery piglets. A total of 144 weaned piglets (24 days of age; 7.02 ± 1.08 kg) were allocated to four treatments containing 0, 0.33, 0.66, or 0.99% BME for 42 days. Performance variables were assessed at the pen level, and laboratory analyses were performed using one representative piglet per selected pen. No consistent dose–response effects were observed for body weight, average daily gain, feed intake, or diarrhea incidence throughout the nursery period. A linear increase in feed conversion ratio was detected during the pre-starter II phase ( P = 0.023), but no cumulative performance effects were observed over the overall nursery period. Antioxidant enzyme activities, leukocyte populations, and fecal SCFA concentrations were unaffected by BME inclusion ( P > 0.05). Microbial alpha diversity indices were unchanged; however, specific microbial taxa, including Veillonellaceae, Mitsuokella , and Mogibacterium , differed among inclusion levels. Overall, dietary BME up to 0.99% did not improve growth performance, immune parameters, antioxidant status, or intestinal fermentation in nursery piglets, although modest shifts in microbial composition were observed.