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.

Some members of the low-density lipoprotein receptor (LDLR) family play important roles in the regulation of lipoprotein metabolism and egg quality traits. Low-density lipoprotein receptor-related protein 2 (LRP2) gene belongs to the LDLR super family, and widely expresses in many tissues. This work identified and genotyped 1 single-nucleotide polymorphism (SNP), T14347C, at 3'-UTR of the LRP2 using matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF MS), and analyzed the effects of the SNP (T14347C) on egg-quality traits in 544 dwarf hens from 44 sire families. Frequencies of this SNP in the studied population did not agree with the Hardy-Weinberg equilibrium (P < 0.0001). Egg weight, albumen weight, albumen height, and albumen ratio of the TT genotype were significantly higher than those of the CC genotype (P < 0.05), whereas eggshell ratio of the TT genotype was significantly lower than that of the CC genotype (P < 0.05). The relative expression level of the LRP2 gene in the magnum was determined by real-time quantitative PCR. The gene expression of genotype CC individuals was significantly higher than that of TT and CT birds (P < 0.05). By combining both genetic effects and expression analyses results, we propose that the LRP2 gene is a good candidate gene, exhibiting a key role in albumen formation processes.

Obesity, a pandemic of modern world, is a chronic disease that seriously affects human health. The causes of obesity are complicated, including environmental factors and genetic factors. Due to the fact that traditional animal models cannot fully mimic obesity in human, new animal models are urgently needed for basic drug research on obesity. Previous studies have demonstrated that the genomic diversity of the wild mice chromosome 1 substitution lines was significantly different from that of laboratory mice, suggesting that it might be accompanied by phenotypic diversity. We firstly screened the obesity-related phenotype of chromosome 1 substitution lines and found that the male chow-diet-fed B6-Chr1YP1 mice showed severe obesity-related phenotypes in body weight, lipid metabolism and liver lesions. Compared with C57BL/6J mice, B6-Chr1YP1 showed much more severe obesity-related phenotypes when fed with high-fat-diet. Furthermore, we evaluated efficacy effects of Tirzepatide and MGL-3196 in B6-Chr1YP1 mice, and obesity-related phenotypes were significantly rescued. Taken together, male B6-Chr1YP1 mice could serve as a novel, polygenic interaction-based obesity and hyperlipidemia model. This study could provide a novel animal model for accurate clinical diagnosis and precise medicine of obesity and hyperlipidemia. Disclosure H.Qi: None. X.Yang: None. J.Zheng: None. Y.Hou: None. Z.Chen: None. Z.Li: None. C.Ju: None. J.Zhao: None. X.Gao: None.