Abstract
BackgroundIntramuscular fat (IMF) is one of the important factors influencing meat quality, however, for chickens, the molecular regulatory mechanisms underlying this trait have not yet been determined. In this study, a systematic identification of candidate genes and new pathways related to IMF deposition in chicken breast tissue has been made using gene expression profiles of two distinct breeds: Beijing-you (BJY), a slow-growing Chinese breed possessing high meat quality and Arbor Acres (AA), a commercial fast-growing broiler line.ResultsAgilent cDNA microarray analyses were conducted to determine gene expression profiles of breast muscle sampled at different developmental stages of BJY and AA chickens. Relative to d 1 when there is no detectable IMF, breast muscle at d 21, d 42, d 90 and d 120 (only for BJY) contained 1310 differentially expressed genes (DEGs) in BJY and 1080 DEGs in AA. Of these, 34–70 DEGs related to lipid metabolism or muscle development processes were examined further in each breed based on Gene Ontology (GO) analysis. The expression of several DEGs was correlated, positively or negatively, with the changing patterns of lipid content or breast weight across the ages sampled, indicating that those genes may play key roles in these developmental processes. In addition, based on KEGG pathway analysis of DEGs in both BJY and AA chickens, it was found that in addition to pathways affecting lipid metabolism (pathways for MAPK & PPAR signaling), cell junction-related pathways (tight junction, ECM-receptor interaction, focal adhesion, regulation of actin cytoskeleton), which play a prominent role in maintaining the integrity of tissues, could contribute to the IMF deposition.ConclusionThe results of this study identified potential candidate genes associated with chicken IMF deposition and imply that IMF deposition in chicken breast muscle is regulated and mediated not only by genes and pathways related to lipid metabolism and muscle development, but also by others involved in cell junctions. These findings establish the groundwork and provide new clues for deciphering the molecular mechanisms underlying IMF deposition in poultry. Further studies at the translational and posttranslational level are now required to validate the genes and pathways identified here.
Highlights
Intramuscular fat (IMF) is one of the important factors influencing meat quality, for chickens, the molecular regulatory mechanisms underlying this trait have not yet been determined
We suggest that processes related to cell junctions might interact with pathways related to lipid metabolism, mainly through MAPK activity, to influence the deposition of IMF
With aim of identifing global candidate genes and new pathways related to IMF deposition in chicken breast, Agilent cDNA microarray analyses were performed with both fast- and slow- growing breeds
Summary
Intramuscular fat (IMF) is one of the important factors influencing meat quality, for chickens, the molecular regulatory mechanisms underlying this trait have not yet been determined. The impressive progress made in these traits, has been accompanied by deterioration of taste quality of the broiler meat and, in Intramuscular fat (IMF), located in most species in the epimysium, perimysium and endomysium, is an important determinant of meat quality. Previous studies found that the IMF content of chicken meat increased with age from d 28 to d 90 [9,10] and may increase further after that (d 90-d 140), along with flavor and taste of the meat [11]
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