The Relationship between Performance, Body Composition, and Processing Yield in Broilers: A Systematic Review and Meta-Regression

SIMPLE SUMMARY: Performance, body composition, and processing yield are important traits in broiler production. Quantifying their association will favor making decisions and better understanding the underlying processes involved in productive and economic efficiency. This study aimed to approach this topic by modeling the relationships between these groups of variables by applying regression to data from multiple studies. The study suggests that regardless of the intervention applied and the type of broilers, the feed conversion ratio improves when the body weight gain also increases. The study’s results support the use of body composition to predict the carcass conformation of broilers and their economic value. The information provided herein may particularly be of value to point out in the right direction further modeling efforts in areas related to poultry economics and sustainability. ABSTRACT: This study aims to model the relationship among performance, whole body composition, and processing yield through meta-regression. Scientific papers found in Scopus and Google Scholar were included if they reported results and variability values of an actual experiment in the three mentioned groups of variables using a single broiler genetic line. Weighted mean effect sizes were determined with a random model, the risk of bias was determined, and heterogeneity was considered an indicator of usefulness. Meta-regressions considered the effect sizes of the response variable and the percent change in one or more variables as predictors. A 78-row database was built from 14 papers, including nine factors tested on 22,256 broilers. No influencing bias was found, and the data was determined useful. Meta-regressions showed that the changes in body weight gain (BWG) are inversely related to the effects in feed conversion ratio (FCR) (p < 0.001) and that the changes in FCR and effects in protein-to-fat gain (PFG) are directly related (p < 0.001). The changes in PFG and the effects on carcass conformation or the market value of birds are directly related (p < 0.001). In conclusion, body composition predicts carcass conformation and its market value, supporting its use to predict the economic value of broilers.