Association Of FABP Gene Polymorphisms With IMF Content In Hetian-Black Chickens And Three-Yellow Chickens

Hetian black chicken (HTBC) was included in the "National Animal Genetic Resources Protection List", in 2010. HTBC is a kind of local varieties with egg and meat, and it has vitality, resilience, strong disease resistance, high temperature tolerance, strong adaptability, outstanding tolerance to cold, high survival rate and fresh meat as well as unique flavor. Due to the lack of breeding guidance system, excellent characteristics varieties are growing degradation. Intramuscular Fat (IMF) content mainly affects flavor, tenderness and juiciness of meat, and Adipocyte fatty acid-binding protein (A-FABP) and Heart fatty acid-binding protein (H-FABP) are two most important genes which affect IMF deposition.The project intends to detect the association of the two gene polymorphism with the IMF contents in order to obtain valuable polymorphic loci that could be used in breeding. The correlation between the two gene mRNA expression quantity and IMF content is also analyzed for study of the IMF.Therefore, the IMF content of cardiac muscles, chest muscles and leg muscles in three yellow chicken (TYC) and HTBC are determined by the method of Soxhlet extraction according to the national standard GB/T 14772-2008. The results show that the highest IMF content is discovered in cardiac muscles of both TYC and HTBC, what’s more, the IMF content of cardiac muscles are significantly higher than those in chest muscles and leg muscles. The IMF content in the three tissues of TYC are significantly higher than those in HTBC. A-FABP and H-FABP gene CDs sequences of TYC and HTBC are acquired by the method of PCR, the results show that they code 132 and 133 amino acids, respectively. The polymorphisms in exon of A-FABP and H-FABP in TYC and HTBC are analyzed by the method of PCR-SSCP. The results show that a C51T mutation site is detected in the first exon of A-FABP gene in both TYC and HTBC, and this site can be used as a genetic marker selection chest high IMF content of HTBC. Three mutations of H-FABP gene second exon following G939A, G982A and C1014T are detected in both TYC and HTBC, and the G982A mutation cite can be used as genetic markers in breeding chest high IMF content of HTBC. The method of real-time PCR is used to detect the mRNA expression of A-FABP gene and H-FABP gene in the cardiac muscle, chest muscle and leg muscle of both TYC and HTBC. The results show that A-FABP mRNA expression in cardiac muscles, chest muscles and leg muscles of TYC are higher than those in HTBC, but significant difference is observed only in chest muscles.A-FABP gene mRNA expression levels in chest muscles are significantly higher than those in cardiac muscles and leg muscles of the two birds.The positive correlation is observed between A-FABP gene mRNA expression and IMF content of chest muscle and leg muscle in both TYC and HTBC. H-FABP gene mRNA expression in cardiac muscle and leg muscle of TYC are significantly higher than those of HTBC, however, the H-FABP gene mRNA expression in chest muscle of TYC is lower than that of HTBC. H-FABP gene mRNA expression amount in cardiac muscle is higher than those in chest muscle and leg muscle of TYC, what’s more, the H-FABP gene mRNA expression in leg muscle is significantly higher than that in chest muscle of TYC. The correlation of H-FABP gene mRNA expression and IMF content in cardiac muscle, chest muscle and leg muscle of TYC are all significantly negative. The association between H-FABP gene mRNA expression and IMF content in both chest muscle and leg muscle of HTBC are significantly negative, too. H-FABP protein expression in cardiac muscle, chest muscle and leg muscle of both TYC and HTBC are detected by the method of Westen blot.The results indicate that H-FABP protein expression in both cardiac muscle and leg muscle of TYC are higher than those in HTBC, however, H-FABP protein expression in chest muscle of TYC are lower than that in HTBC. But no significant difference is detected in all of them. H-FABP protein in cardiac muscle, chest muscle and leg muscle of both TYC and HTBC are tested by the method of immunohistochemistry (IHC). The results show, H-FABP protein expresses in cytoplasm. H-FABP protein expression in both cardiac muscle and leg muscle of TYC are higher than those in HTBC.Both of the mutation site C51T of A-FABP and the mutation site G982A of H-FABP could be taken as genetic markers in breeding for selecting the high content of IMF in chest muscle of HTBC. The association of A-FABP and H-FABP gene mRNA expression and IMF content in breast and leg muscle of HTBC were significant positive and negative correlations, respectively.