Genotyping of H-FABP loci in two pig ancient autochthonous genetic types: Calabrese and Casertana

The aim of the present research was to characterize two pig ancient autochthonous genetic types (AAGT) [Casertana (CT) and Calabrese (CA)] at H-FABP (Heart- Fatty Acid Binding Protein) loci as well as to evaluate the associations of qualitative and quantitative meat traits. H-FABP is a candidate DNA segment coding protein (gene) for intramuscular fat depot (IMF). The identification of haplotypes suitable for IMF may represent a valid tool for molecular assisted selection (MAS) to improve meat qualitative traits functional to human well being and welfare. Genotyping was performed on 150 pigs (100 CT and 50 CA) reared at ConSDABI Experimental Farm by PCR-RFLP (Polymerase Chain Reaction – Restriction Fragment Lenght Polymorphism) method. Three diallelic point mutations were investigated: one located in a 700 bp sequence in the 5’upstream region (HinfI restriction site) and two in a 850 bp sequence, about 300 bp apart, located in intron 2 (HaeIII and MspI restriction sites, respectively) of the H-FABP DNA segment; in total, these mutations map in a region of about 7.000 bp and may define a three locus haplotype. Some qualitative characteristics (colour and rheological traits) were detected on Psoas Major, Longissimus dorsi, Caput longum tricipitis brachii and Supraspinatus muscles of 59 CT and 50 CA. Experimental data were analyzed using carcass weight as covariate (SAS package) and the significance of comparisons between the estimated mean values was tested by Student’s t test. 27 possible haplotypes taking into account the diallelic polymorphism of each locus were calculated. The results, in the limits of the observation field, showed some haplotypes ‘AAGT- exclusive’ [3 in Casertana (HHDdAA; HHDDAa; HHddaa) and 2 in Calabrese (hhddAA; hhddaa)] and a different incidence of the common haplotypes: in CT the most frequent was HHddAa (38%) while in CA was HhddAa (22%). The relation between genetic structure of H-FABP loci and quanti-qualitative characteristics of meat evidenced the association between H-FABP loci and fatty traits. CA carriers of HhddAa haplotype evidenced a significant higher backfat weight (19.11 kg) in comparison with carriers of HHddaa haplotype which showed the lower fatness (6.35 kg); furthermore, the former haplotype also affected the fatness in other cuts (jowl and belly). Animals with the hhddAA haplotype evidenced a higher thickness of backfat at shoulder level (79.41 mm), while HhddAa showed the lowest value in the Calabrese AAGT. A different chromatic behavior of meat was observed in relation to both muscle type and haplotype. In Casertana, meat of HHDdAA carriers was lighter as consequence of the highest lightness value (43.44; P<0.05) while in Calabrese the HHDdAa haplotype was associated with a higher lightness value (45.84; P<0.05). The statistical analysis did not evidence associations between haplotype and dissection data.