Hemoglobin polymorphism and its association with morphometric and egg production traits in Ethiopian indigenous and Sasso chicken breeds.

The present study investigated the biochemical polymorphism of hemoglobin (Hb) and its relationship with performance traits of Ethiopian indigenous and Sasso chicken breeds. A total of 284 chickens reared in three agro-ecologies were examined for genetic diversity and associations with productive traits at Hb locus using agarose gel electrophoresis. The results showed that the Hb A allele was dominant in both breeds, and a higher proportion of male chickens were Hb AA genotypes, while females were predominantly Hb BB types. In the highland agro-ecology, chickens with the Hb AA genotype were the most dominant, whereas in mid- and low-land agro-ecologies, chickens with Hb BB and Hb AB genotypes were found to be more frequent. A moderate level of expected heterozygosity was obtained with 0.47 and 0.445 for indigenous and Sasso chickens, respectively, with an average effective number of alleles per locus of 1.89 and 1.80. Moreover, chickens with Hb AA genotypes showed significantly (p ≤ 0.05) higher body weight and linear body measurements than those of Hb AB and Hb BB genotypes. However, for appendage body structures (comb and wattle dimensions), chickens with the Hb AB and Hb BB genotypes had higher mean values. Additionally, clutch size (14.2 ± 0.4), clutch length (21.8 ± 0.7), and eight-month egg production (84.1 ± 1.2) were significantly (p ≤ 0.05) higher for hens with Hb BB genotypes, followed by those with Hb AB -types. Therefore, the considerable hemoglobin variability and significant associations of Hb variants with the performance traits can be sought as guiding information for further genetic improvement interventions in the chicken breeds under investigation. Further microsatellite marker-based genotyping is recommended to validate the higher morphometric values for Hb AA genotypes and the better egg production for Hb BB and Hb AB genotypes.