Efficacy ofprobiotic in preventing necrotic enteritis in broilers: a systematic review and meta-analysis.

Abstract

Probiotics can enhance broiler chicken health by improving intestinal microbiota, potentially replacing antibiotics. They protect against bacterial diseases like necrotic enteritis (NE) in poultry. Understanding their role is crucial for managing bacterial diseases, including NE. This study conducted a meta-analysis to assess the effects ofprobiotic supplementation on feed conversion ratio (FCR), NE lesion score, and mortality. Additionally, a systematic review analysed gut microbiota changes in broilers challenged withwith or without the probiotic supplementation. Effect sizes from the studies were estimated in terms of standardized mean difference (SMD). Random effect models were fitted to estimate the pooled effect size and 95% confidence interval (CI) of the pooled effect size between the control [probiotic-free&#x2009;+&#x2009;] and the treatment [supplemented&#x2009;+&#x2009;] groups. Overall variance was computed by heterogeneity (Q). The meta-analysis showed thatprobiotic supplementation significantly improved FCR and reduced NE lesion score but had no effect on mortality rates. The estimated overall effects of probiotic supplementation on FCR, NE lesion score and mortality percentage in terms of SMD were -0.91 (CI&#x2009;=&#x2009;-1.34, -0.49;&#x2009;<&#x2009;0.001*); -0.67 (CI&#x2009;=&#x2009;-1.11, -0.22;&#x2009;=&#x2009;0.006*), and -0.32 (CI&#x2009;=&#x2009;-0.70, 0.06;&#x2009;=&#x2009;0.08), respectively. Heterogeneity analysis indicated significant variations across studies for FCR (Q&#x2009;=&#x2009;69.66;&#x2009;<&#x2009;0.001*) and NE lesion score (Q&#x2009;=&#x2009;42.35;&#x2009;<&#x2009;0.001*) while heterogeneity was not significant for mortality (Q&#x2009;=&#x2009;2.72;&#x2009;=&#x2009;0.74).probiotic supplementation enriched specific gut microbiota including. These microbiotas were found to upregulate expression of various genes such as TJ proteins occluding, ZO-1, junctional adhesion 2 (JAM2), interferon gamma, IL12-&#x3b2; and transforming growth factor-&#x3b2;4. Moreover, downregulated mucin-2 expression was involved in restoring the intestinal physical barrier, reducing intestinal inflammation, and recovering the physiological functions of damaged intestines. These findings highlight the potential benefits of probiotic supplementation in poultry management, particularly in combating bacterial diseases and promoting intestinal health.