Effect of g.2728g > A and g.3996t > C polymorphisms at the leptin gene locus on microstructure and physicochemical properties of longissimus lumborum muscle of Polish Landrace pigs.

The influence ofHindIII (g.2728G > A) and Bg/II (g.3996 T > C) polymorphisms at the leptin gene locus on muscle fibre characteristics and meat quality of longissimus lumborum muscle was studied in 146 barrows of the Polish Landrace breed. Leptin gene polymorphism was identified by PCR-RFLP. Fibre type percentage, fibre diameter and the following technological parameters ofmeat were also determined: pH45, pH24, Lab* colour, drip loss, water holding capacity, shear force and intramuscular fat content. Polymorphism was not detected in the locus studied in the Landrace pig herd analysed with the Bg/II restriction enzyme (g.3996 T > C). For the HindIII enzyme (g.2728G > A), there was a high frequency of GG homozygotes (0.78) and G allele (0.89), but the AA genotype was not present. Moreover, the genotypes ofleptin gene RFLP-HindIII polymorphism had no effect on intramuscular fat content and muscle fibre type percentage, but had a significant effect on muscle fibre size. Heterozygous GA fatteners had a significantly larger (P < 0.05) diameter of type IIB and type I fibres compared to homozygous GG fatteners. Generally, meat quality parameters were comparable among the examined genotypes except for water holding capacity (which was the lowest for the GG genotype) and colour lightness (L*) (which was the lightest for GA genotype). Moreover, regardless of genotype, large differences were observed between each animal in the distribution of intramuscular fat.