Meta-Analysis: The effect of post-hatch delayed feed access on the physiological conditions of broiler chickens during the golden period

Abstract

This meta-analysis aimed to conduct a systematic review and statistical analysis regarding the effects of post-hatch delayed access feed (DAF) on the physiological conditions of broiler chickens during the golden period. The materials were obtained from international journals, comprising 113 case studies collected from 11 selected and relevant journals. From various relevant parameters, six blood profiles and biochemical parameters were selected for the meta-analysis: glucose levels, cholesterol levels, total protein, heterophil counts, lymphocyte counts, and the heterophil-to-lymphocyte (H/L) ratio. Observations have focused on the impact of DAF during the golden period in chicks aged 1–7 days. The data were tabulated and analyzed using meta-analysis with JASP software version 0.18.3.0. DAF had negative effects, including increased cholesterol levels, heterophil counts, and H/L ratio. However, it did not negatively affect glucose or total protein levels. Publication bias was identified in several DAF variable moderators related to glucose, total protein heterophile, lymphocyte, and H/L parameters, suggesting potential research outcome manipulation or interpretive bias. In conclusion, delayed feed access consistently exacerbates physiological conditions, as indicated by elevated cholesterol levels, heterophil counts, and H/L ratio in broiler chickens during the golden period.