Meta-analysis of the Use of Leaf Extract as Alternative Growth Promoter in Broiler Chickens

Abstract

Plants, especially on the leaves, have various bioactive compounds capable of becoming natural growth promoters. Plant leaf extracts have been widely studied for their ability as an antibiotic substitute for broiler chickens. This meta-analysis study was aimed to assess the effectiveness of supplementations with leaf extract on the growth performance of broiler chickens, using average daily feed intake (ADFI), average daily gain (ADG), final body weight (FBW), and feed conversion ratio (FCR) as responses observed criteria. The meta-analysis study was based on the articles published from 2006 to recent years as several countries started to ban in-feed antibiotics. Databases (PubMed, Scopus, Directory of Open Access Journals [DOAJ], and ScienceDirect) were searched for peer-reviewed randomised controlled trials (RCTs) published in English. The meta-analysis included 19 research papers that met the criteria. Overall results showed a significant increase (<i>P</i> < 0.001) in ADFI by 0.56 g/day (95% confidence interval [CI] = 0.02 to 1.11), in ADG by 1.57 g/day (95% CI = 0.77 to 2.36), and in FBW by 2.28 (95% CI = 1.40 to 3.16). At the same time, the FCR was reduced (<i>P</i> < 0.001) by -1.25 (95% CI = -1.76 to -0.73) relative to controls taking cognisance of publication bias and heterogeneity. Results in the current meta-analysis study indicated that herbal feed additives were proven to be effective as growth promoters in broiler chickens.