Avian

Phenotypic and genomic characterization of body weight traits of African chickens reared under semi-scavenging conditions

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Abstract

Smallholder poultry systems based on indigenous chickens are dominant in Africa. Implementing selective breeding can enhance growth traits thereby improving livelihoods for smallholder farmers. This study aims to estimate phenotypic descriptive values and variance components and identify genomic markers associated with body weight traits of indigenous Tilili chickens reared in semi-scavenging conditions in Ethiopia. A total of 3,933 chickens were raised outdoors for ten weeks (from 70 to 133 days old) at the International Livestock Research Institute (ILRI) poultry research facility in Addis Ababa, Ethiopia. The body weight of individual chickens was measured and recorded weekly. Genotyping by sequencing was performed on all chickens using a low-coverage and imputation approach. After filtering and quality control, 2.2 million Single Nucleotide Polymorphisms (SNPs) remained for downstream analyses. Phenotypic and genotypic data were combined in mixed effect models to perform single-trait and single-step genome wide association studies (GWAS and ssGWAS). Genetic parameters for body weight and growth across weeks were estimated based on genomic and pedigree data. Body weight traits were significantly affected (P + 13.8 grams for males. Average estimated inbreeding coefficient (F̂ = 0.013), hints the population is reasonably outbred. A polygenic architecture was observed for all body weight with heritability estimate of 0.21 + 0.03 (H-matrix) for BW16. GWAS (using a genome-wide Bonferroni-corrected threshold of P -8, where α=0.05) identified 39 significant SNPs associated with BW16 on chromosome 1 (17.3 to 17.4 Mb) and chromosome 4 (75.7 to 75.9 Mb), with notable loci near the LCORL, SPRYD7, gga-miR-15a, and MED28. Functional enrichment analysis on ssGWAS output revealed several significant (P DNTT, IMPACT, EGF, PRRX1). In conclusion, our findings highlight low level of inbreeding and considerable significant genomic variation and heritability for body weight traits in indigenous Ethiopian Tilili chickens. These results underscore the promising opportunities for selective breeding, especially with increased selection intensity, to improve growth performance in smallholder systems.

Keywords: 2026

How to Cite:

Banos, G., Davoudi, P., Dessie, T., Esatu, W., Girma, M., Hanotte, O., Kassa, B., Kebede, F., Solomon, B., Tarsani, E. & Watson, K., (2026) “Phenotypic and genomic characterization of body weight traits of African chickens reared under semi-scavenging conditions”, World Congress on Genetics Applied to Livestock Production Digital Archive 2026(1): 2283858. doi: https://doi.org/10.31274/wcgalp.23529

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