Phenotypic characterization of chicken inbred lines that differ extremely in growth, body composition and egg production traits

The development of phenotypically and genetically divergent inbred chicken lines as simplified genetic models facilitates the identification of genes and contributes to the elucidation of gene functions. In this study, we characterized a New Hampshire (NH) population with its partial inbred derivative, New Hampshire inbred (NHI), and a White Leghorn inbred line (WL77). Both NHI and WL77 lines were inbred after selection for high meat yield or low egg weight, respectively. The inbreeding levels in NHI and WL77 are about 86% and 100%, respectively. Animals of the NHI line grew twice as fast, were about two times as heavy at 20 weeks, and deposited 9.3 times as much fat as WL77. NHI females reached sexual maturity, indicated by age at first egg, earlier, had a 35% higher egg production ratio, and their eggs were on average 6 g heavier compared to WL77 females. The NHI and WL77 lines were extremely different for most traits, which makes them suitable for cross-bred experiments to map quantitative trait loci and identify genes contributing to the observed differences.