Associação da expressão de genes candidatos com teor de gordura intramuscular no músculo Longissimus dorsi de suínos / Association of candidate gene expression with intramuscular fat content in the porcine Longissimus dorsi muscle

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

This work was realized with the objective to provide information about the expression pattern of candidate genes, by real-time polymerase chain reaction (qPCR), and correlate it to intramuscular fat (IMF) content in pigs from both sexes, of Piau, Commercial and Crossbred genetic groups, slaughtered at 30, 60, 90 and 120Kg. Longissimus dorsi muscle samples were taken for IMF measurement and RNA extraction. The studied genes were ATN1, EEF1A2, FABP3, LDLR, MGP, OBSCN, PDHB, RYR1 and TRDN. Higher levels of IMF (P<0.05) were reported for Piau and Crossbred pigs slaughtered at 120Kg, indicating that alleles from Piau animals have important role in fat deposition. Irrespective of genetic group, expression of ATN1, FABP3 and PDHB genes were affected (P<0.05) by slaughter weight. PDHB was affected by genetic group (P<0.05) whereas Piau and Crossbred showed higher expression values than Commercial animals (P<0.05). In EEF1A2 gene, genetic group was significant (P<0.05) and its expression was higher in Crossbred pigs (P<0.05). Expression levels of LDLR, MGP, OBSCN, RYR1 and TRDN were affected by the interaction of genetic group and slaughter weight (P<0.05). Among genetic groups, it was possible to determine predicting equations (P<0.05) of expression levels of LDLR, OBSCN, RYR1 and TRDN genes for Piau animals. Moreover, Piau was the only genetic group that showed an expression pattern on LDLR gene. Slaughter weight affected MGP expression (P<0.05) in Commercial and Crossbred pigs. It was also possible to establish (P<0.05) a pattern of expression for genes OBSCN, RYR1 and TRDN in Crossbred animals. Moreover, these three genes were influenced by genetic group within slaughter weight (P<0.05). Commercial animals showed higher values of OBSCN expression (P<0.05) at 30 and 90Kg of slaughter weight, but expression levels in Piau pigs were not different (P>0.05) from them at 90Kg. For RYR1 gene, it was observed higher expression levels (P<0.05) in Piau pigs at 30, 90 e 120Kg, but no significance (P>0.05) was observed between expression means between Piau and Commercial pigs at 30Kg. Piau animals presented higher levels of TRDN expression than Commercial pigs (P<0.05) at 60Kg ofslaughter weight. Using predicted values, levels of expression from all genes were correlated to IMF content using data from all animals and only from Piau pigs. Using the whole data, expression levels of FABP3, LDLR, TRDN, OBSCN, RYR1 and PDHB genes were positively correlated (P<0.05) with IMF content while EEF1A2 showed negative correlation (P<0.05). In Piau animals, MGP was negatively correlated (P<0.05) with IMF and, LDLR, FABP3, TRDN, RYR1 and OBSCN genes positively (P<0.05). A prediction equation for IMF content, for all genetic groups, sexes and slaughter weights, was modeled using adjusted values of all genes. The coefficient of determination (R2) associated to this equation was 90.29%, where ATN1, EEF1A2, MGP and PDHB genes act lowering IMF levels and LDLR, OBSCN and TRDN increasing fat deposition in longissimus dorsi muscle. The higher potential of IMF deposition observed in Piau pigs, indicates that this breed may carry valuable genes for determine lipid deposition in muscle. Although some genes were correlated and included in the prediction equation, LDLR gene showed to play an important role on the determination of IMF levels, due its high values of correlation and regression coefficient, and biological function of lipid recruitment into the cell. Thus, more studies are required to assign this gene as a candidate gene for intramuscular fat deposition in longissimus dorsi muscle in pigs.

ASSUNTO(S)

meat quality qualidade da carne genetica e melhoramento dos animais domesticos tempo real pcr real time pcr

ACESSO AO ARTIGO

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