Attapulgite-enhanced probiotic delivery reprograms gut microbiota and metabolism to improve growth performance and immune function in broilers

This study evaluated the effects of attapulgite (APT) combined with Lactiplantibacillus plantarum (LP) and Limosilactobacillus reuteri (LR) on growth performance, intestinal barrier function, immune response, and cecal microbiota in broiler chickens, aiming to develop an effective antibiotic alternative. In vitro simulated gastrointestinal digestion demonstrated that APT significantly improved the survival of LP and LR, with scanning electron microscopy confirming bacterial adsorption onto APT. A total of 160 one-day-old broilers were assigned to dietary treatments, and growth performance, nutrient digestibility, serum biochemical and immunological indices, intestinal morphology, tight junction protein expression, cecal microbiota, and metabolomic profiles were analyzed. The combined APT-probiotic treatment significantly improved average daily gain and feed conversion ratio (P < 0.05), with effects comparable to antibiotic supplementation. It enhanced serum immunoglobulins (IgA, IgG, IgM) and IL-10 levels while reducing IL-6, and increased antioxidant capacity. Intestinal barrier integrity was improved, as indicated by increased villus height-to-crypt depth ratio and upregulation of ZO-1, Occludin, Claudin1, and MUC2. Microbiota analysis revealed enrichment of Bacteroidetes and short-chain fatty acid-producing genera, accompanied by increased concentrations of acetate, butyrate, and valerate (P < 0.05). Metabolomics further indicated enhanced pathways related to energy metabolism and antioxidant defense. In conclusion, APT-enhanced probiotic supplementation improves growth performance and gut health by modulating the microbiota-metabolite axis, highlighting its potential as a sustainable antibiotic alternative in poultry production.