Cathepsins, growth hormone-releasing hormone (GHRH) and leptin receptor (LEPR) genes have been receiving increasing attention as potential markers for meat quality and pig performance traits. This study investigated the allele variants in four cathepsin genes (CTSB, CTSK, CTSL, CTSS), GHRH and LEPR in pure-bred Ukrainian Large White pigs and evaluated effects of the allele variants on meat quality characteristics. The study was conducted on 72 pigs. Genotyping was performed using PCR–RFLP technique. Meat quality characteristics analysed were intramuscular fat content, tenderness, total water content, ultimate pH, crude protein and ashes. A medium level of heterozygosity values was established for GHRH and LEPR genes which corresponded to very high levels of informativeness indexes. Cathepsins CTSL, CTSB and CTSK had a low level of heterozygosity, and CTSS did not segregate in this breed. Association studies established that intramuscular fat content and tenderness were affected by the allele variance in GHRH and LEPR but not by CTSB and CTSL genes. The GHRH results could be particularly relevant for the production of lean prime cuts as the A allele is associated with both, a lower meat fat content and better tenderness values, which are two attributes highly regarded by consumers. Results of this study suggest that selective breeding towards GHRH/AA genotype would be particularly useful for improving meat quality characteristics in the production systems involving lean Large White lines, which typically have less than 2 % intramuscular fat content.
Leptin receptor is one of the components of the system of regulating energy homeostasis of the organism. Leptin receptor gene (LEPR) polymorphism is associated with pig carcass index of the content of intramus- cular fat in its valuable parts, which is particularly important when assessing the quality of their carcasses for processing. Intramuscular fat is associated with meat fl avor characteristics and partly determines its tenderness, juiciness, and other parameters. Aim. To analyze LEPR gene (SNP NM001024587.1, p. 1987 C > T) polymor- phism in populations of various pig breeds and to establish its relationship with the quality of both meat and fat of pigs of Large White breed of Ukrainian breeding. Methods. Genetic-population analysis of nine pig breeds, associative analysis on the search connection of LEPR gene polymorphism with quality of both meat and fat of pigs of Large White breed of Ukrainian breeding. LEPR locus genotyping was performed by High Resolution Melting (HRM). Results. All the studied
breeds are characterized by polymorphism of the leptin receptor gene (SNP NM001024587.1, p. 1987 C > T), signifi cant breed specifi city in the distribution of frequencies of alleles was established. Statistically confi rmed effect (p < 0.05) of genotypes LEPR on the content of intramuscular fat, total dry matter and moisture in the meat, as well as the moisture content in the back fat of pigs of Ukrainian Large White breed was revealed. Higher content of intramuscular fat was found in the animals with genotype TT, while a smaller amount of intramuscular fat and more moisture in fat was revealed in heterozygotes. Conclusions. Genetic marker LEPR SNP NM001024587.1, p. 1987 C > T can be used in the marker-assisted selection to predict and improve the performance quality of the meat of pigs of Large White breed of the Ukrainian breeding. These results suggest that porcine leptin receptor gene controls the quality of fat comp- lex – inside muscles and in the dorsal part of the carcass.