Effects of Dietary Supplementation with Liquor Distillers’ Grains with Solubles on Growth Performance, Nutrient Digestibility, Serum Parameters, and Fecal Microbiota of Late-Phase Nursery Yacha Pigs

This study aimed to investigate the effects of dietary inclusion of liquor distillers’ grains with solubles (LDGS) on growth performance, serum biochemical parameters, immune and antioxidant status, short-chain fatty acid (SCFA) and fecal microbial diversity in late-phase nursery Yacha pigs. The experiment involved 240 healthy 60-day-old pigs with an initial body weight of 23.99 ± 1.00 kg. These pigs were assigned randomly to five treatment groups, each consisting of eight replicate pens and six pigs per pen. The control group (CON) received a basal diet, while the four treatment groups were supplied with basal diets with 2%, 3%, 4% and 5% LDGS, respectively. Compared with the CON group, BUN levels were significantly lower in the 3% supplement group (p < 0.05). These results suggest changes in nitrogen metabolism, but there were no significant differences in ADG or F/G. Meanwhile, compared with the CON group, the 3% group showed significant changes in anti-inflammatory cytokine IL-10 levels, glutathione peroxidase (GSH-Px) activity, and total antioxidant capacity (T-AOC) (p < 0.05). Serum IgG was also significantly higher, but the absolute increase was small. The 3% supplementation group had the highest fecal SCFA concentrations, with acetic acid concentrations significantly elevated relative to the control group (p < 0.05). Regarding microbial diversity, in the 3% and 4% supplementation groups, the relative abundance of butyrate-producing bacteria, such as Terrisporobacter, was significantly higher than that in the control group (p < 0.05), while the relative abundance of the opportunistic pathogen Streptococcus was significantly decreased in the 3%, 4% and 5% groups (p < 0.05). Overall, multiple indicators declined at the 4% or 5% LDGS inclusion level. The 3% dietary LDGS supplementation level led to relatively better gut health and helped maintain balanced anti-inflammatory and antioxidant homeostasis, but ADG and F/G did not differ significantly from the control. Therefore, among the inclusion levels tested, 3% LDGS was associated with favorable overall responses in late-phase nursery Yacha pigs.