Abstract
In the prevention and control of animal diseases, synbiotics combine the principles of probiotics and prebiotics, which play crucial roles in reducing intestinal disorders, such as diarrhea and indigestion, enhancing immune function, and decreasing the incidence of respiratory diseases in livestock and poultry. Following the confirmation of the prebiotic activity of lentinan, this study aimed to use microencapsulation technology to prepare synbiotics composed of Lactiplantibacillus plantarum (L. plantarum) and lentinan. The optimal preparation process for the synbiotic microcapsules was determined through single-factor, orthogonal, and response surface experiments. Subsequent experiments on storage stability, gastric acid tolerance, and intestinal release characteristics confirmed that the microencapsulated L. plantarum-lentinan synbiotic exhibited increased resistance to adverse environments. The microencapsulated synbiotic was ultimately incorporated into antibiotic-free feed at a dosage of 1 × 10(9) CFU/kg for broilers. The results indicated that this synbiotic could increase the average daily weight gain and feed conversion ratio of 28-day-old broiler chickens, increase the immune organ index, improve the morphology of the intestinal villi, and effectively increase the activity of digestive enzymes in the small intestine. Moreover, changes in the cecal microbial community composition of broilers were observed, with an increase in the number of Lactobacillus and a decrease in the number of Escherichia coli. In summary, this synbiotic can effectively enhance the growth performance of broilers, regulate the intestinal microbiota, improve immune function, and reduce the risk of intestinal and respiratory diseases in broilers. GRAPHICAL ABSTRACT: [Image: see text] SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13568-025-01929-y.