Polymorphism in the gene FABP3 and its association with indicators of meat quality in pigs

© Slovak University of Agriculture in Nitra Faculty of Agrobiology and Food Resources


Introduction
Meat quality is defined by the characteristics of sensory experience and meat technological quality traits.A higher level of intramuscular fat (IMF) has a positive influence on the pork sensory characteristics and shows a positive correlation with meat tenderness, juiciness, and taste (Fernandez et al., 1999;Reardon et al., 2010).The fatty acid composition of pork has been analyzed due to its effects on meat quality and its association with human health (Wang et al., 2013).
The objective of this investigation was to correlate the variability in FABP3 gene (heart fatty acid-binding protein) with the IMF content and fatty acid composition in muscle of Czech Large White pigs.

Material and methods
For this study, 104 pigs of the breed Czech Large White were selected from nucleus herd.Blood samples were collected immediately after slaughter into EDTA tubes.
Meat quality was evaluated in all individuals by the following features: meat color (L, a, b), pH ultimate, drip loss, the electrical conductivity of the meat, dry matter, the percentage and content of intramuscular fat, and fatty acids composition.
Polymorphism was analyzed by PCR-RFLP method.Primers for amplification of the fragments were taken from a study of Pang et al. (2006) with modifications for the specific conditions of our laboratory: FW: 5'-GGACCCAAGATGCCTACGCCG-3' and RV: 5'-CTGC AGCTTTGACCAAGAGG-3' .The size of the resulting PCR product was 693 bp.The PCR reaction mixture was prepared on ice in a total volume of 25 μl containing 2 μl of genomic DNA, 0.5 μl dNTP mix, 0.5 μl, FW primer, 0.5 μl RV primer, 0.2 μl polymerase pd.Unis, 2.5 μl buffer, and 18.8 μl H 2 O.The amplification conditions were as follows: 94 °C for 3 min, 35 cycles of 94 °C for 30 s, 62 °C for 30 s, 72 °C for 50 s, and a final extension of 72 °C for 10 min.SNP X98558 g.1321 G > C in 5´ UTR region of FABP3 was analyzed by HinfI restriction endonuclease.PCR product was digested overnight with 3 U HinfI in a total volume of 15 μl at 37 °C, and subsequently size-separated on 3.0% agarose gel.
Association analysis was performed in SAS (Ver.9.1.4,SAS Institute, Cay, NC, USA) by general linear model with one fixed effect of genotype of FABP3 gene.

Results and discussion
The polymorphism X98558g.1321G> C detected in 5´ UTR region of FABP3 gene was genotyped in Czech Large White pigs (Figure1).The 693 bp PCR product of the G/C polymorphism of 5'UTR of the FABP3 gene was digested with HinfI, cleaving the H allele into four fragments (339, 172, 98 + 59 bp) and cleaving the h allele into four fragments (339, 231, 98 +25 bp).
Frequencies of alleles H and h were 0.93 and 0.07, respectively.The genotype frequencies HH = 0.87 and Hh = 0.13 were at Hardy-Weinberg equilibrium.
Association analysis performed with studied SNP revealed statistically significant differences between genotypes of FABP3 gene and quality of pork (Table 1).It can be concluded that HH genotype had a lighter meat color, lower pH (more acidic) and thus drip loss was higher than in genotype Hh.But these values are not statistically significant.HH genotype tended to a higher proportion of red and yellow meat color.Furthermore, this genotype shows tendency to higher content of fatty acids: myristoleic acid, palmitoleic acid, oleic acid and EPA, and intramuscular fat content.Hh genotype was found with higher content of palmitic (P < 0.01), stearic (P < 0.05), arachidonic, linoleic (P < 0.01) acids, and genotype Hh has also been found to have higher percentage of dry matter content.However, only differences in content of stearic acid, linoleic acid and palmitic acid were statistically significant.

Conclusions
The porcine FABP3 gene showed significant association with content of palmitic acid, stearic acid and linoleic acid: animals of genotype Hh had higher content of palmitic and linoleic acids than those of genotype HH (P < 0.01), and individuals with Hh genotype had higher content of stearic acid than those with HH genotypes (P < 0.05).