A systematic review and meta-analysis of the efficacy of organic acids in reducing Salmonella colonization in the crop and ceca of broilers.

Abstract

Organic acids have been widely used as feed and water supplements during broiler grow-out and feed withdrawal to reduce Salmonella colonization, with variable efficacy. This systematic review and meta-analysis evaluated the efficacy of supplementing organic acids delivery route (water or feed) on the prevalence and concentrations of Salmonella in the crop and ceca of broilers. A total of 2,290 identified publications were screened, 22 (prevalence) and 25 (concentration) publications met inclusion criteria. Mean values, standard deviations, and replicates for control and treatment groups were extracted to calculate the mean difference (log CFU) from studies reported concentration results. The number of positives and sample size were extracted to calculate the odds ratio from studies reporting prevalence results. Data were analyzed using meta package in R (&#x3b1; = 0.1). All models had a medium or high heterogeneity (I> 50 %), therefore, results from the random effect model were reported. Meta-analysis revealed that supplementing organic acids via feed reduced the odds of Salmonella positives in the crop by 84 % compared to the control (P < 0.01), while supplementation through drinking water was less effective, reducing the odds by 57 % compared with the control (P < 0.01). Both water and feed delivery routes reduced the odds of Salmonella positives in the ceca by 62 % and 66 %, respectively (P < 0.01). Organic acid supplementation in the drinking water and feed was estimated to reduce Salmonella concentration in the crop by 0.70 (P < 0.01) and 0.92 log CFU (P = 0.062), respectively. Similarly, both routes are estimated to reduce Salmonella concentration in the ceca by 0.72 log CFU from water and 1.59 log CFU from feed, respectively (P < 0.01). Organic acid supplementation effectively reduces Salmonella in broilers at pre-harvest, with feed delivery generally showing greater efficacy for prevalence reduction. However, caution should be exercised when incorporating organic acids, and their optimal dosage and safety must be evaluated before implementation.