Meta-analysis of the impact of garlic supplementation on aspects of egg yolk quality characteristics of laying hens

Ogbuewu, I. P. and Mbajiorgu, C. A.

International Journal of Agriculture and Biology (2022) 28: 319–326

DOI: 10.17957/IJAB/15.1984

Abstract

Phytogenic feed additives (PFAs) have been highlighted to increase animal performance and product quality. However, the effect of garlic (Allium sativum L), one of such PFAs on the internal egg quality indices of laying hens is less clear. As a result, this meta-analysis investigated the impact of garlic supplementation on egg yolk weight (EYW) and egg yolk cholesterol (EYC) content in laying hens. A search carried out in three online databases yielded five hundred and ten studies of which fifteen passed the predefined selection conditions for the meta-analysis. Inclusion criteria were information on moderator variables (hen’s age, layer strains, presentation form, treatment duration, inclusion level, and the number of hens used for the study), and outcome measures (EYW and EYC) with their corresponding measures of variance. All analyses were performed in OpenMEE software. Results indicate that addition of garlic to layer diets increased EYW by 0.063 g [95% confidence interval (CI)=95% CI: -0.051, 0.176] compared to zero, though the difference was not statistically significant. Similarly, garlic supplementation reduced EYC concentrations by 0.641 mg/g yolk (95% CI: -0.059, -0.424) in comparison with controls, taking publication bias and heterogeneity into consideration. Subgroup and meta-regression analyses revealed that modifiers had impact on the results and conclusion. In conclusion, our results suggest that garlic supplementation improved egg yolk quality parameters in laying hens.

Citation

Ogbuewu, I. P., & Mbajiorgu, C. A. (2022). Meta-analysis of the impact of garlic supplementation on aspects of egg yolk quality characteristics of laying hens. International Journal of Agriculture and Biology, 28(5), 319–326. https://doi.org/10.17957/IJAB/15.1984 meta-analysis, diets, chemical composition, poultry, egg weight, hens, feed additives, cholesterol, plant composition, plant extracts, egg production, eggs, hen feeding, egg quality, garlic, Ovum, egg yolk, egg yolk composition

Keywords

• meta-analysis
• diets
• chemical composition
• poultry
• egg weight
• hens
• feed additives
• cholesterol
• plant composition
• plant extracts
• egg production
• eggs
• hen feeding
• egg quality
• garlic
• Ovum
• egg yolk
• egg yolk composition