Comparisons Of Muscle Fat Content, Fatty Acids Compositions Between Jian Carp And Red Purse Carp And Correlation Analysis Of Ccapos Transcriptional Levels With C18:1

The intramuscular fat (IMF) content, muscular fatty acids compositions were determinated in Cyprinus carpio var. jian and Cyprinus carpio var. wuyuanensis, which propagated simultaneously and farmed in the same pond. The results showed that, the IMF content of jian carp(2.28%) was significantly lower than that of red purse carp (3.56%) (P<0.01). Both the contents of total saturated fatty acids (SFA) (26.99±1.40%) and polyunsaturated fatty acids (PUFA) (48.94±1.88%), especially for DHA+EPA in jian carp were higher than that of red purse carp (P<0.01), while the content of mona-unsaturated fatty acids(MUFA)(19.97±3.10)was lower than that of red purse carp (28.20±3.98)(P<0.01). Correlation analysis showed that, the content of IMF was positively correlated with oleic acid (C18:1) (R2=0.61, P<0.01); and DHA showed a negative correlation with C18:1 (R2=0.73, P<0.01).The apolipoprotein (Apo) are important component of plasma lipoproteins, which play important role in the processes of lipid uptake, transport and metabolism. Six CcApo genes belonging to Apo-A-Ⅰb、Apo-A-Ⅳ、Apo-C-Ⅰ respectively, were cloned from two strains carp, here denoted as CcApo-A-Ⅰb1、CcApo-A-Ⅰb2、CcApo-A-Ⅳ1、CcApo-A-Ⅳ2、 CcApo-C-Ⅰα、 CcApo-C-Ⅰb. Six CcApo genes all contained 3 introns and 4 exons, and the intron sequences of each pair of genes were different significantly. The amino acids sequences of apolipoproteins in common carp exhibit about 80% similarity with their counterparts in zebrafish except CcApo-A-Ⅳ2. The phylogenetic tree shows that, six CcApos were divided into two clusters, Apo-C and Apo-A, CcApo-C-Ⅰs gathered in Apo-C cluster, while CcApo-A-Ⅰbs, CcApo-A-Ⅳ1 and 2 were gathered into Apo-A cluster, but the branch distinction between Apo-A-Ⅰ and Apo-A-Ⅳ was not obvious withing low bootstrap. It’s shown that, the genetic distance of Apos were consistent with their classification status in the class level from the phylogenetic tree, but in the level of order and family, the species evolution level can not identified.Expressing levels of these three pair of Apo genes in two carps’ different tissues were detected using real time-PCR, the result showed that, the CcApo genes expressed in diffent tissues, but mainly in liver. In addition, there were also higher expression levels of CcApo-A-Ⅳ1,2 in intestine, and Apo-C-Is in brain. Except CcApo-A-Ⅰbs, the expression level of Apo-C-Ⅰs in red purse carp liver was 1.5 times higher than that of jian carp (P<0.05), while CcApo-A-Ⅳ1 and 2 transcriptional levels in red purse carp liver was lower than that of jian carp (P<0.05), and no significant difference was found in CcApo-A-Ⅰs expressional levels between two carp strans. In muscle, all of the CcApos expression levels of red purse carp were higher than that of jian carp, but only the CcApo-A-Ⅳ2 were different significantly(P<0.01). Correlation analysis showed that, the CcApo-C-Ⅰs expression level in liver was positively correlated with oleic acid (C18:1), which content was the highest in muscle triglyceride (R2=0.40, P<0.01); while CcApo-A-Ⅳ1 and 2 showed a negative correlation with C18:1 (R2=0.45,0.52, P<0.01). Considering the functions of Apo-C-I, Apo-A-Ⅳ, we deduced that the higher expression levels of CcApo-C-Is and the lower expression levels of CcApo-A-Ⅳ1,2 in liver were partly responsible for the higher content of C18:1 and IMF in red purse carp, which Can be used as molecular markers associated with IMF.