Meta-analysis of the inclusion of leaf meals in diets of broiler chickens.

The effects of leaf meals on growth performance of broiler chickens have been evaluated in different studies. However, no consensus has been obtained due to the variability of the results. The present study, therefore, aimed to provide a meta-analysis of randomized controlled trials examining the effects of feeding leaf meals on growth performance of broiler chickens. Literature was searched using Google Scholar, Science Direct, Scopus, and CAB Abstracts. References from eligible studies were also thoroughly reviewed to identify additional studies. Keywords used for searching the articles were leaf meals, broilers, growing, finishing, and performance. The response measures extracted from individual studies for analysis were average daily feed intake (ADFI), average daily gain (ADG), feed conversion ratio (FCR), sample size, and standard error of the mean. Eighteen studies were included in the meta-analysis. Average daily feed intake, ADG, and FCR responses to leaf meal-based diets average - 4.82 g, - 5.44 g, and 0.40, respectively. Combining the effect size estimates, our data were highly heterogeneous for ADFI (98.57%) and FCR (81%), and a moderate heterogeneity for ADG (65.11%). Evidence of publication bias was visually confirmed for ADFI, ADG, and FCR from the funnel plots. However, using the weight-function model did not show any evidence of publication bias for ADG (P > 0.05). The meta-analysis study has indicated that leaf meals can positively influence growth performance in chickens.