Efficacy of Probiotic Supplementation in Broilers Challenged with Coccidiosis: A Meta-Analysis

Coccidiosis caused by Eimeria species remains a major enteric disease in broiler production, impairing growth and increasing mortality. Concerns regarding anticoccidial drug resistance have driven interest in probiotics as non-antibiotic alternatives. This meta-analysis quantitatively assessed the efficacy of probiotic supplementation in experimentally infected broiler chickens with Eimeria species. In accordance with the PRISMA 2020 standards, searches were conducted on September 26, 2025, in PubMed, Scopus, and Web of Science for English-language papers published between 2020 and 2025. Eligible studies included randomized controlled trials that reported quantifiable outcomes on growth performance (body weight gain [BWG], feed intake [FI], and feed conversion ratio [FCR]), or health performance (lesion score and mortality). Data were retrieved as mean ± SD or event counts and pooled using random-effects models in R (meta and metafor packages). The SYRCLE’s Risk of Bias tool was used to evaluate methodological quality. Fifteen studies comprising more than 9,000 broilers fulfilled the inclusion criteria. Probiotic supplementation markedly enhanced body weight gain (MD = 67.72 g/bird, 95% CI: 7.91 to 127.53; p = 0.0265, I² = 85.2%) and reduced feed conversion ratio (MD = − 0.07, 95% CI: − 0.11 to − 0.03; p = 0.0014, I² = 76.5%). Lesion scores significantly decreased (MD = − 0.91, 95% CI: − 1.34 to − 0.49; p = 0.001, I² = 95.4%), and mortality decreased by 64% (OR = 0.36, 95% CI: 0.14–0.93; p = 0.0399, I² = 11.1%). Probiotic supplementation had no significant impact on FI. Meta-regression demonstrated that sample size and route of probiotic administration moderated body weight gain (R² = 100%), route of administration and broiler strain explained heterogeneity in feed intake (R² = 75.39%), comparator type accounted for heterogeneity in feed conversion ratio (R² = 100%), and group size influenced lesion scores (50 birds/group: estimate = − 1.59; R² = 87.36%). Sensitivity analysis validated the robustness of the findings, and Egger’s test indicated no significant publication bias. In summary, probiotic treatment significantly improved growth performance and reduced intestinal lesion and mortality in broilers challenged with Eimeria. These findings support the use of probiotics as effective and sustainable alternatives to anticoccidial drugs in broilers production. However, strain-specific optimization and standardized reporting are necessary for its widespread implementation.