Effect of dietary turmeric powder on egg quality and yolk cholesterol level of laying hens: a meta-analysis

Turmeric powder (TP) has been extensively used as a feed additive alternative for antibiotic growth promoters. Turmeric's bioactive components not only enhance laying hen performance but also the quality of laying hen eggs. The objectives of this meta-analysis were to assess the effectiveness of supplementation with turmeric powder on egg weight (EW), haugh unit (HU), eggshell thickness (EST), yolk color (YC) and yolk cholesterol level (YCL) of laying hen eggs. Peer-reviewed randomized controlled trials (RCTs) published in English were found using databases such as PubMed, Scopus, Science Direct and Google Scholar. The meta-analysis required information on moderators (breed of hens, age of the hen at the start of the intervention, inclusion level and turmeric powder treatment duration), a sufficient description of randomization, performance data and associated measures of variance such as standard deviation (SD) or standard error (SE). All analyses were carried out using the Open Meta-analyst for Ecology and Evolution (OpenMEE) program. Data from the 17 studies included in the meta-analysis were pooled and presented as standardized mean differences (SMDs) at a 95 confidence interval (CI) using a random-effects model. Results indicate that dietary TP supplementation improves HU (SMD = 0.88; 95 CI: 0.30 to 1.47), EST (SMD = 0.62 mm; 95 CI: 0.13 to 1.11), YC (SMD = 2.06; 95 CI: 1.32 to 2.80) and YCL (SMD = -1.19; 95 CI: -2.23 to -0.15) compared with the controls. Restricted subgroup analysis indicated that brown laying hen showed the beneficial effect of dietary turmeric powder. Subgroup analysis found that studies that used TP in <11 g/kg had significant egg quality. The meta-analysis explains that turmeric powder is an ingredient that could be used as a feed additive in laying hens to increase egg quality. © 2023 Fundacion CIPAV. All rights reserved.