Genetic Expression of IGF-1 and IGF-2 in Nigerian Sheep Breeds: Implications for Growth and Productivity

This research investigates the genetic and phenotypic variability among three Nigerian indigenous sheep breeds (Balami, Uda, and Yankasa) by assessing morphometric characteristics and gene expression profiles of Insulin-like Growth Factors (IGF-1 and IGF-2). A total of 45 sheep (15 per breed), aged 1 to 5 years and comprising 20 males and 25 females, were analyzed for body weight, height at withers, heart girth, and body length. Sample distribution was as follows: Balami (9 males, 6 females), Uda (6 males, 9 females), and Yankasa (5 males, 10 females). Gene expression from muscle, kidney, and heart tissues was evaluated via real-time PCR. Significant breed, age, and sex effects (P<0.05) were observed across morphometric traits and gene expression levels. Balami sheep showed notably superior body measurements, suggesting a strong potential for meat production. IGF-1 expression exceeded IGF-2 across all breeds, with Balami having the highest IGF-1 levels. Notably, females exhibited increased IGF-2 expression, potentially influenced by hormonal factors. Age-related variation in gene expression indicates dynamic developmental phases. The integration of molecular and phenotypic evaluations enhances selection programs aimed at breed improvement and conservation of genetic diversity. Keywords: Indigenous sheep breeds, Genetic diversity, Phenotypic variation, Morphometric traits, IGF-1 and IGF-2, Gene expression, Livestock improvement.