Lipid profiles and production performance responses of laying hens to dietary Moringa oleifera leaf meal: systematic review and meta-analysis

The inclusion of Moringa oleifera leaf meal (MLM) in chicken diets especially in developing countries is on the increase due to scarcity of traditional feedstuffs. Therefore, this investigation aimed to explore the effects of MLM on lipid profiles and production characteristics of laying hens. Twenty-three publications retrieved from Web of Science, PubMed, Scopus and Google Scholar search engines were used for the analysis. Data from the 23 studies were analysed using random-effects model in OpenMEE software. Results were presented as standardised mean difference (SMD) at a 95% confidence interval. The results show significant improvement in feed conversion ratio (SMD = - 0.49; p < .001), egg mass (SMD = 0.35; p = .003), Haugh unit (SMD = 0.39; p < .001), eggshell thickness (SMD = 0.63; p < .001) and eggshell weight (SMD = 0.45; p < .001) at a reduced feed intake. On the other hand, egg weight, hen-day egg production and blood high-density lipoprotein cholesterol were not statistically different from controls. Results reveal that dietary MLM enhanced blood cholesterol, low-density lipoprotein (LDL) cholesterol, triglycerides and yolk cholesterol concentrations in laying hens. There is presence of significant heterogeneity and meta-regression revealed that study country, number of hen, housing system, hen age, inclusion level and layer strains were predictors of the treatment effect. In conclusion, the results of this meta-analysis suggest that inclusion of MLM in the diet of laying hens improved feed conversion ratio, aspects of egg quality and blood/yolk cholesterol concentrations in laying hens at a reduced feed intake.