A Meta-analysis on the Effects of Postbiotics on Growth Performance and Gut Morphology in Broiler Chickens

Recent research has highlighted the potential of postbiotics as alternatives to antibiotic growth promoters (AGPs) in broiler production. The impact of postbiotics on growth performance and gut health in broilers has shown inconsistent findings, influenced by parameters such as postbiotic type, dosage, and delivery techniques. This meta-analysis aimed to assess the impact of postbiotics on broiler growth performance, including average daily gain (ADG), body weight (BW), feed intake (FI) and feed conversion ratio (FCR), in addition to gut morphology metrics, such as villus height (VH) and crypt depth (CD). A comprehensive search was performed in PubMed, Scopus, and Web of Science databases. A total of 30 studies were selected from an initial group of 413 studies. The research included randomized controlled trials and observational studies published from 2015 to 2025. Effect sizes were computed using Cohen's d, while publication bias was evaluated through funnel plots and Egger's test. The Cochran Q test was used to assess heterogeneity among studies, employing a random-effects model for cases with statistically significant heterogeneity. Subgroup analyses were conducted according to postbiotic type, sample size, and age of broilers. The meta-analysis results indicated a positive impact of postbiotics on ADG and BW, especially for bacterial-based postbiotics such as Lactiplantibacillus plantarum and Bacillus subtilis. The meta-analysis also indicated a positive impact of fermented based postbiotics on feed intake (FI) of broilers. Nonetheless, the impact on gut morphology was inconsistent, with considerable diversity noted among studies. Heterogeneity was significant, with variables including postbiotic type, sample size, and age of broilers influencing outcome variability. In conclusion, although postbiotics have potential as substitutes for AGPs, their impact on grill growth and gut health remains inconsistent. This study highlights the necessity for more research to standardize postbiotic therapies and investigate their long-term impacts on poultry productivity.