Association of LEPR polymorphisms with egg production and growth performance in female Japanese quails

This study aimed to screen intron 8 of the leptin receptor (LEPR) gene for polymorphisms in female Japanese quails. Two adjacent novel SNPs (A277G and A304G) were detected using PCR-SSCP and sequencing. These SNPs produced three haplotypes (AA/AA, AG/AG, and GG/GG) that were significantly (p <= 0.05) associated with growth and egg production traits. GG/GG haplotype-quails had significantly (p <= 0.05) lower egg production, feed intake, growth performance, lipid profile, serum levels of sex hormones (estradiol, progesterone, FSH, LH), and ovarian expressions of survivin,FSHR, andIGF1than other quails. However, GG/GG quails had significantly (p <= 0.05) higher serum levels of LEP and mRNA levels of LEPR, LEP, and caspase 3 in the hypothalamus and ovaries. These higher levels of LEP/LEPRcould not only reduce feed intake and body weight gain but also could induce apoptosis of ovarian cells (as indicated by lower survivin andIGF1and higher caspase3 expression) which could inhibit the development of the follicles and the release of sex hormones with a subsequent decrease in egg production in GG/GG quails. Therefore, with these results, we suggest selecting Japanese quails with AA/AA and AG/AG haplotypes to improve the reproduction and growth performance of this flock.

Automated summary

This study identified novel SNPs in the leptin receptor gene of female Japanese quails, which were significantly associated with growth and egg production traits. Quails with the GG/GG haplotype showed lower egg production, feed intake, and growth performance, as well as altered lipid profile and sex hormone levels. However, they exhibited higher levels of LEP/LEPR and apoptosis-related genes in the hypothalamus and ovaries. The study suggests selecting quails with the AA/AA and AG/AG haplotypes to improve reproduction and growth performance.