Effects of Host-Specific Multi-Lactic Acid Bacterial Probiotics on Performance, Carcass Traits, Meat Quality, and Gut Microbiome in Fattening Pigs

This study evaluated the effects of a host-specific multi-lactic acid bacterial (MLAB) probiotic and sex on performance, carcass traits, meat quality, and gut microbiota in fattening pigs. Thirty-two crossbred pigs (10 ± 0.80 weeks; 23.43 ± 0.17 kg) were assigned to a 2 × 2 factorial design with diet (control or MLAB probiotics) and sex (barrow or female). The MLAB supplement consisted of seven lactic acid bacterial strains mixed in equal proportions (≈14.3% each)—Lactobacillus brevis, Lactobacillus reuteri, Weissella cibaria, Lactobacillus paraplantarum, Lactococcus lactis, Lactobacillus pentosus, and Pediococcus pentosaceus—administered at 1 × 109 CFU/kg feed for 12 weeks. MLAB probiotic supplementation reduced bone proportion while increasing skin and fat content (p < 0.05), with a treatment × sex interaction for loin eye area (p < 0.05). Meat quality improved in the MLAB group, showing higher ultimate pH and lower cooking loss (p < 0.05), indicating improved water-holding capacity. Female pigs exhibited higher early postmortem pH and protein content (p < 0.05). Microbiome analysis revealed increased abundances of Oxalobacteraceae and Paludibacteraceae and reduced Clostridium sensu stricto 6 (p < 0.05). These results suggest that host-adapted probiotics may support gut microbial balance and improve certain pork quality traits.