Low-density lipoprotein receptor-related protein 8 gene association with egg traits in dwarf chickens.

Low-density lipoprotein receptor-related protein 8 (LRP8), a member of the low-density lipoprotein receptor gene family with a role in clusterin processing, was investigated as a candidate gene for egg quality-related traits. One SNP from C to T at position 1623 of the open reading frame of LRP8 was identified and genotyped by a high-throughput genotyping method, matrix-assisted laser desorption-ionization time-of-flight mass spectrometry in 747 egg-type dwarf layers from 44 sire families. There were no significant differences among genotypes for any interior egg traits measured, except for yolk color, in which color was deeper for the TT genotype than CC or CT (P < 0.05). For shell traits, strength and thickness were greater for TT than CC (P < 0.05), with CT intermediate and not different from either. Shape index was lower for CT than either TT or CC, which did not differ, whereas for shell color, CT was intermediate to the homozygotes, which differed (CC > TT). The present results indicated that LRP8, as a new member of eggshell matrix protein, may be a candidate gene associated with eggshell traits.