Comparative Study of Three Indigenous Chicken Breeds of South Africa: Body Weight and Linear Body Measurements

Morphometric differentiation of three chicken ecotypes of Ethiopia using multivariate analysis

Twenty-one morphometric traits were measured on 770 extensively managed indigenous chickens in the western zone of Tigray, comprising 412 hens and 358 cocks in three agro-ecologies. The quantitative traits for male and female chicken ecotypes were separately analyzed using multivariate analysis with SAS 2008. Four and seven principal components accounted for about 74.26% and 69.77% of the total variability in morphometric traits for males and females, respectively. Earlobe length, wingspan, skull length, and shank length werethe most important traits for discriminating among female chicken ecotypes, while wingspan, neck length, earlobe length, spur length, body length, and shank length were the most important discriminatory traits among male chicken ecotypes. The discriminant analysis accurately classified 97.3% of female and 100% of male chicken ecotypes. Cluster analysis revealed the genetic heterogeneity of indigenous chicken populations in both sexes. This finding suggests the presence of morphological variations among the indigenous chicken populations in the different agro-ecological zones, classified as distinct indigenous chicken ecotypes (Lowland, Midland, and Highland). Further DNA-based studies are needed to confirm and complement these morphological variations for effective conservation and the development of sustainable genetic improvement strategies for indigenous chicken populations in the region.

Genetic and Phenotypic Characterization of Domestic Geese (Anser anser) in Egypt

The objectives of this study were to achieve phenotypic characterization of three domestic Egyptian goose populations collected from three different geographical zones (Kafr El-Sheikh, Fayoum and Luxor) and to perform genetic characterization of these three populations based on mtDNA D-loop and 12 microsatellite markers. The body measurements of 402 domestic mature geese belonging to these three governorates showed that the lengths of the head, culmen and tarsus and the live body weight varied significantly among the three studied Egyptian goose populations. After alignment of a 710-base-pair segment of the goose mtDNA control region, there was a single haplotype in the three Egyptian goose populations, indicating the same maternal origins. The genotyping of the 12 microsatellite markers showed low diversity indices, including average observed (NA) and effective (NE) number of alleles and observed (HO) and expected heterozygosity (HE) (3.333, 1.760, 0.277 and 0.352, respectively), and a high inbreeding coefficient (FIS = 0.203) across the three Egyptian goose populations. The high inbreeding and low genetic and morphological differentiation of Egyptian geese could be corrected by establishing a large base population through capturing small populations with the highest genetic variation. The findings of the current study can therefore serve as an initial guide to design further investigations for developing conservation programs of Egyptian geese genetic resources.

Application of principal component analysis for predicting body weight of Ethiopian indigenous chicken populations

BACKGROUND AND OBJECTIVE

Under smallholder management conditions, where weighing scale is not readily available, body weight (BW) can be predicted from morphometric measurements using multiple regression. However, the statistical interpretation of the regression parameters estimated by least squares is difficult due to multicollinearity problems. Thus, principal component analysis (PCA) was used to predict BW from body measurements, including body length (BL), chest circumference (CC), shank length (SL), and shank circumference (SC) of Ethiopian indigenous chicken populations reared by smallholder farmers. The effectiveness of this technique was also compared with the traditional multiple regression analysis (MRA).

MATERIALS AND METHODS

Measurements were taken from 134 male and 487 female chickens. The whole dataset was partitioned into two portions, namely, training and testing datasets, for model comparison and validation purposes. The training dataset, which consisted of 75% of the dataset, was used to develop the model, and the testing dataset, which consisted of 25% of the dataset, was used to validate the model.

RESULTS

The PCA results revealed that the variables for body measurements were represented by PC1 and PC2 in male birds and PC1, PC2, and PC3 in female birds. Regression models developed using scores derived from these PCs explained 88 and 69% of total variation in BW in male and female birds, respectively. Compared with traditional MRA, regression models generated using the PCA procedure were more accurate in predicting BW.

CONCLUSION

Thus, the results of the present study could not only be used for predicting BW of Ethiopian indigenous chickens but also in their genetic selection programs.

Phenotypic variability and population structure analysis of Tanzanian free-range local chickens

BACKGROUND

Free-range local chickens (FRLC) farming is an important activity in Tanzania, however, they have not been well-characterized. This study aimed to phenotypically characterize three Tanzanian FRLCs and to determine their population structure. A total of 389 mature breeder chickens (324 females and 65 males) from three popular Tanzanian FRLC ecotypes (Kuchi, Morogoro-medium and Ching'wekwe) were used for the phenotypic characterization. Progenies of these chickens were utilized to assess population structure. The ecotypes were collected from four geographical zones across Tanzania: Lake, Central, Northern and Coastal zones. Body weights and linear measurements were obtained from the mature breeders, including body, neck, shanks, wingspan, chest girth, and shank girth. Descriptive statistics were utilized to characterize the chickens. Correlations between the linear measurements and differences among the means of measured linear traits between ecotypes and between sexes were assessed. A total of 1399 progeny chicks were genotyped using a chicken 600 K high density single nucleotide polymorphism (SNP) panel for determination of population structure.

RESULTS

The means for most traits were significantly higher in Kuchi relative to Ching'wekwe and Morogoro-medium. However, shank length and shank girth were similar between Kuchi and Morogoro-medium females. All traits were correlated with the exception of shank girth in Morogoro-medium. Admixture analyses revealed that Morogoro-medium and Ching'wekwe clustered together as one population, separate from Kuchi.

CONCLUSIONS

Phenotypic traits could be used to characterize FRLCs, however, there were variations in traits among individuals within ecotypes; therefore, complementary genomic methods should be considered to improve the characterization for selective breeding.