EXPRESSION OF INSULIN GROWTH FACTOR GENES IN NIGERIAN LOCAL CHICKENS WITH DIFFERENT PLUMAGE PATHERNS
African Local Chicken (ALC) ecotypes, especially Nigerian Local Chicken (NLC) are unique and precious source of indigenous poultry genetic resources with evolutionary fitness and strong ability to adapt to the extreme tropical conditions. Thus this study was designed to understand the intricate relationship between five major qualitative plumage phenotypes, Normal Feathered, Naked Neck, Frizzle Feathered, Feathered Shank (Ptylopody), and Crested and their growth architectures. The absolute quantitative molecular expression was profile with a precise and multi-dimensional morphometric analysis in the experimental model. The precise and multi-dimensional morphometric analysis was combined with the absolute quantitative molecular expression profiling. The phenotypic skeletal development was measured in relation to linear structural dimensions and quantitative real-time polymerase chain reaction (qPCR) was used to quantify the relative mRNA transcription levels of Insulin-like Growth Factor-I (IGF-I) using biologically different tissue matrices, namely hepatic tissue (liver), deep structural pectoral muscle and blood.
The morphometric data showed very different growth patterns among the cohorts. Body girth was found to be a critical structural focus among the variant with very high, highly significant positive correlation coefficients with back length having r of 0.660, followed by body depth (r = 0.584) and keel length (r = 0.538). At the molecular level, the real-time transcription profiles showed different tissue-specific differences with respect to the gene expression. The liver-dominant endocrine phenotype (classical) was characterized by the Frizzle feather pattern as they had exceptionally high transcription of IGF-I and IGF-II mRNA in the liver and moderate to low levels in peripheral tissues.
Keywords: Nigerian Local Chickens · Plumage gene mutations · Linear morphometrics · Somatotropic endocrine axis · IGF-I gene expression
