Dietary crude glycerol as an energy source in broiler chickens: a meta-analysis

Sulaimon, Rasheed Olayiwola; Oyeniyi, Ridwan Olalekan; Sopian, Yusup; Sahatsanon, Katatikarn; Jayanegara, Anuraga; Sivapirunthep, Panneepa; Patthararangsarith, Pattraphorn; Chaosap, Chanporn

doi:.0.0.0

Anim Biosci > Accepted Articles

Review paper

https://doi.org/10.5713/ab.250686 [Accepted] Published online March 11, 2026.

Dietary crude glycerol as an energy source in broiler chickens: a meta-analysis

Rasheed Olayiwola Sulaimon^1,5

, Ridwan Olalekan Oyeniyi²

, Yusup Sopian¹

, Katatikarn Sahatsanon¹

, Anuraga Jayanegara³

, Panneepa Sivapirunthep⁴

, Pattraphorn Patthararangsarith⁴

, Chanporn Chaosap^4,*

¹Doctoral Program in Innovative Tropical Agriculture, School of Industrial Education and Technology, King Mongkut’s Institute of Technology Ladkrabang, Bangkok, Thailand., Bangkok, Thailand
²Department of Animal Production, Faculty of Agriculture, University of Ilorin, Ilorin, Kwara State, Nigeria. , Ilorin, Nigeria
³Department of Animal Nutrition and Feed Technology, Faculty of Animal Science, IPB University, Bogor, Indonesia., Bogor, Indonesia
⁴Department of Agricultural Education, School of Industrial Education and Technology, King Mongkut’s Institute of Technology Ladkrabang, Bangkok, Thailand. , Bangkok, Thailand
⁵Department of Animal Science, Faculty of Agriculture, University of Abuja, Abuja, Nigeria., Abuja, Nigeria

Correspondence: Chanporn Chaosap, Tel: +66-83-882-9217, Email: chanporn.ch@kmitl.ac.th

Received: 19 September 2025 • Revised: 15 December 2025 • Accepted: 9 March 2026

Abstract

Objective
s: This meta-analysis evaluated the effects of dietary crude glycerol (CG) supplementation on growth performance, carcass traits, meat quality, and blood biochemical parameters in broiler chickens.
Methods
A systematic search of peer-reviewed studies in Scopus, ScienceDirect, and Google Scholar was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol. Twenty-five eligible studies were included. Effect sizes were calculated as standardized mean differences (SMDs) using a random-effects model in OpenMEE software. Subgroup analyses were performed according to strain, sex, rearing phase, and inclusion level.
Results
CG supplementation significantly increased body weight gain (p < 0.05) and improved feed conversion ratio (p < 0.05), while feed intake was unaffected. Among carcass traits, breast yield significantly increased (p < 0.05), whereas carcass yield and thigh yield were not affected. CG inclusion also reduced meat ash content and ultimate pH, while drip loss increased, indicating potential negative effects on water-holding capacity. Blood biochemical indices, including reduced alanine aminotransferase (ALT) and elevated alkaline phosphatase (ALP), indicated adaptive physiological responses without evidence of toxicity. Subgroup analyses revealed that strain, sex, and inclusion level significantly moderated growth outcomes (p < 0.05).
Conclusion
Crude glycerol can be incorporated into broiler diets as an alternative energy source to enhance growth performance without compromising carcass yield. However, its influence on meat quality highlights the need to optimize inclusion levels and consider variability among glycerol by-products before large-scale application.

Keywords: Broiler chickens; Crude glycerol; Meta-analysis; Performance; Rearing phase; Strain