ABSTRACT
There is still limited information on the genomic structure and genetic diversity of African pigs. Genetic diversity studies can contribute significantly to the genetic improvement and conservation of African pigs. This study presents a genetic diversity analysis and population structure of pig breeds in Ghana, with a focus on the Ashanti Dwarf pig (ADP), an indigenous pig breed of Ghana. A total of 167 pigs sampled in Ghana and populations consisting of Ashanti Dwarf pigs (n = 106), exotics (mostly European pigs) (n = 11), crosses (between indigenous and exotic breeds) (n = 44), and unknown breeds (nondescript) (n = 6) were genotyped using Porcine SNP60K BeadChip. Moderate heterozygosity levels, ranging from 0.28 for Ashanti Dwarf pigs to 0.31 for exotic pigs (mostly European pigs), were observed. Principal component analysis of the pig populations within Ghana resulted in two distinct clusters of pigs: (i) Northern and (ii) Southern regional clusters. The PCA based on breed also resulted in four clusters: (i) ADPs; (ii) exotics (iii) crossbreeds between ADP and exotics; (iv) unknown breed types. The PCA demonstrated that the clustering was influenced by genetics, geographical location, production systems, and practices. ADMIXTURE-based analysis also showed that the populations within Ghana are admixed. FST analysis revealed SNPs associated with QTLs for traits such as disease resilience and growth among ADP populations within the different regional and ecological zones of Ghana.
ABSTRACT
This study aimed at investigating the effect of the seasonal decline in quality and availability of feed on rumen function in sheep grazing without supplementation. Effects of season on rumen pH, ammonia nitrogen concentration and rumen degradation of urea-treated rice straw in grazing sheep were determined. Four fistulated Djallonké sheep were added to a group of grazing sheep and used for this study. Rumen contents were sampled for pH and ammonia in the rainy season and in the dry season. Ammoniated rice straw was incubated in the rumen to determine its degradation characteristics. Rumen pH was higher (p < 0.1) in the dry season than in the rainy season. Rumen ammonia nitrogen concentrations on the other hand were similar (p > 0.05) in the two seasons. In sacco dry matter degradation parameters of urea-ammoniated rice straw showed seasonal differences in the soluble (a) and the insoluble but degradable (b) fractions as well as lag time before the start of degradation. It was concluded that despite higher pH in the dry season and similar ammonia nitrogen concentration in the two seasons, rumen degradability of dry matter of urea-treated rice straw in sheep was higher in the rainy season than that in the dry season.
