Identification of differentially expressed genes and pathways for intramuscular fat deposition in pectoralis major tissues of fast-and slow-growing chickens.
BACKGROUND
Intramuscular 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.


RESULTS
Agilent 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.


CONCLUSIONS
The 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.
Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, People's Republic of China.
Huan-Xian
HX
Cui
Ran-Ran
RR
Liu
Gui-Ping
GP
Zhao
Mai-Qing
MQ
Zheng
Ji-Lan
JL
Chen
Jie
J
Wen
D000273:Adipose Tissue / Q000378:metabolism; D000818:Animals; D002645:Chickens / Q000235:genetics* / Q000254:growth & development; D016000:Cluster Analysis; D005260:Female; D020869:Gene Expression Profiling; D053263:Gene Regulatory Networks; D050356:Lipid Metabolism / Q000235:genetics; D008460:Meat / Q000032:analysis; D053858:Metabolic Networks and Pathways; D024510:Muscle Development; D020411:Oligonucleotide Array Sequence Analysis; D010369:Pectoralis Muscles / Q000254:growth & development; D012333:RNA, Messenger / Q000378:metabolism; D058305:Sorting Nexins / Q000235:genetics / Q000378:metabolism; D013997:Time Factors
D012333:RNA, Messenger; D058305:Sorting Nexins