Avian

Genetic Analysis of Egg Production and Quality Traits in Indigenous Tanzanian Chickens

---

Abstract

Indigenous village chickens (ICs) are typically raised in harsh environments, providing low-cost meat and egg-based protein for low-income households in developing countries, but they exhibit poor production performance. Given the unavailability of data on ICs, we recorded egg production and quality traits for three Tanzanian IC ecotypes in single-bird cages: Ching'wekwe (n = 171), Kuchi (n = 220), and Morogoro-medium (n = 404). We estimated genetic parameters for egg production and egg quality traits and identified associated genomic regions, using PCA to assess population structure. Chicks were tagged at hatch, raised together, and females were separated into cages at the point of lay. They were then genotyped using 5K targeted genotyping by sequencing and imputed to the Affymetrix 600K SNP chip. All eggs were collected, weighed, and recorded. Production traits analyzed included egg production per 90 days (EP1 to EP6). Quality traits were assessed for eggs on random days from EP4 to EP6, including egg weight (EW), shape index (SDx), shell thickness (STh), shell weight (SW), albumen weight (AW), and yolk weight (YW). Generalized and linear mixed models were used in ASReml to estimate genetic parameters; GWAS was performed using BayesB (all ecotypes combined). Kuchi laid the most eggs (15.7) while Ching'wekwe laid the least (14.7) and the lightest (41.3 g). Averages for EW, SW, SDx, AW, and YW were 43.3±5.5g, 5.6±1.0g, 74.4±3.5%, 28.7±6.7g, and 14.4±2.0g, respectively. There was no difference in egg quality between ecotypes for SDx, SW, and YW. Heritability estimates for production traits ranged from 0.13±0.10 to 0.59±0.10 for EP, 0.07±0.0 to 0.41±0.10 for EW, and 0.42±0.20 for AFE, and from 0.13 to 0.18 for clutch traits, while those for quality traits ranged from 0 (for SW, STh, and YW) to 0.66 for EW. Permanent environmental effects were absent for most traits, except for SDx (39%) and YH 33%), and for traits with zero heritability, which had repeatabilities ranging from 0.19 to 0.30. Genomic regions (n = 19) were identified on chromosomes 1 to 5, 9, 10, 11, 26, and Z, associated with production (n = 2) and quality (n = 5) traits. Genes in these regions include ERS, SERPINH1, and TPO. When ranked by percentage of genetic variance explained, 0.25 Mb windows across the genome were enriched for features from the QTL and GO libraries related to reproduction, energy metabolism, and other biological processes. In conclusion, although the egg production performance of ICs is low, it can be improved through genetic selection, along with quality. Project funded by USAID, Feed the Future Innovation Lab for Genomics to Improve Poultry (AID-OAA-A-13-00080).

Keywords: 2026

How to Cite:

Magwaba, T., Lamont, S., Wolc, A., Mollel, E., Mushi, J., Walu-gembe, M., Amuzu-Aweh, E., Chiwanga, G., Chouicha, N., Muhairwa, A., Msoffe, P., Kelly, T., Gallardo, R., Zhou, H. & Dekkers, J., (2026) “Genetic Analysis of Egg Production and Quality Traits in Indigenous Tanzanian Chickens”, World Congress on Genetics Applied to Livestock Production Digital Archive 2026(1): 2295774. doi: https://doi.org/10.31274/wcgalp.24370

Rights: 1