Does the Use of Emulsifier or Lipase Improve Weight Gain and Feed Conversion in Broilers? A Systematic Literature Review and Meta-Analysis

Abstract

Emulsifiers and exogenous lipases are feed additives used to increase lipid utilization in broiler diets. A meta-analysis was carried out to quantify the effects of the supplementation of emulsifiers and exogenous lipases on broiler weight gain (BWG, g/broiler/d) and feed conversion ratio (FCR, g/g) during the whole production cycle. Studies were obtained from the PubMed, Scielo, Science Direct, Scopus, and Web of Science databases. A total of 2669 studies were identified, 25 of which composed the database for the meta-analysis, representing data from a total of 14,643 broilers. These results demonstrate that there is evidence in the literature supporting that supplementation with emulsifiers or lipases improves broiler weight gain and feed conversion during the whole production cycle. However, the effect of the additives is influenced by bird sex, lipid source and concentration, type of additive and concentration, energy level of the feed, and bird strains. The isolated use of emulsifiers increases weight gain by 1.62g/day and reduces feed conversion by 0.04. However, there is no evidence that exogenous lipase use alone improves weight gain or feed conversion in broilers during the whole production cycle. The latter result may be due to the small number of studies with the additive in question, rather than its possible effects on weight gain and feed conversion. Therefore, further investigation should be conducted on this topic, especially studies on females fed diets supplemented with lipases.