Metanalysis of the Effects of Emulsifiers and Lipases on Breast, Drumstick and Abdominal Fat Yield in Broiler Chickens

ABSTRACT This meta-analysis evaluated the effect of emulsifiers or lipase as lipid digestibility enhancers on the yield of breast, thigh, and abdominal fat of broilers during the complete production cycle. Primary studies were obtained from the PubMed, Scielo, Science Direct, Scopus, and Web of Science databases, resulting in a total of 2,669. Of these, 18 were selected for meta-analysis, with information from 9,387 chickens. The average difference between breast, drumstick, and abdominal fat yield of chickens that were supplemented or unsupplemented with emulsifier and/or lipase was adopted as the effect size measure in the meta-analysis. Different weights were attributed to the studies by the inverse variance method. The significance of the general average difference was obtained through the Z test. The heterogeneity among studies was verified by the chi-square test and its magnitude was estimated by the index of inconsistency, with the adoption of a model of random effects. Subgroup analyses were performed to evaluate the level of interference of sex, lipidic source and concentration (%), type of additive and concentration (%), metabolizable energy of the feed (kcal/kg), and poultry lineage on final results. Results show there is evidence that emulsifier or lipase supplementation improves breast yield, though it does not improve drumstick yield or deposition of abdominal fat in broiler chickens during the complete cycle period. Further studies are required regarding this issue to quantify the impact of these additives on the observed results.