Project description:The success of turkey breeding for rapid growth rate and larger breast size has coincided with an increasing incidence of a meat quality defect described as pale, soft and exudative (PSE). We hypothesized that this defect, which is associated with an abnormally rapid rate of postmortem metabolism, derives from altered expression of genes involved in metabolic regulation. Our objective was to use deep transcriptome RNA sequence analysis (RNAseq) to identify differentially expressed genes between normal and PSE turkey breasts. Following harvest of turkey breasts (n = 43), the pH at 15 min post-slaughter and percent marinade uptake at 24h post-slaughter were determined. Breast samples were classified as normal or PSE based on marinade uptake (high = normal; low = PSE). Total RNA from samples with the highest (n=4) and lowest (n=4) marinade uptake were isolated and sequenced using the Illumina GAIIX platform. Of 21,340 gene loci discovered by RNAseq, 8480 loci completely matched the turkey reference genome, and 480 genes were differentially expressed (false discovery rate, FDR<0.05) between normal and PSE samples. Two highlights were the genes nephroblastoma overexpressed (NOV), upregulated about 38-fold and pyruvate dehydrogenase kinase isoform 4 (PDK4), downregulated 14-fold in PSE samples. Pathway analysis suggested that several biological functions, including carbohydrate metabolism and energy production, were affected by meat quality. Because PDK4 regulates conversion of pyruvate to acetyl CoA, differences in regulation of oxidative metabolism may exist among turkeys. Accelerated early postmortem metabolism would result in faster pH decline in PSE meat. This hypothesis was supported by the fact that decreased expression of PDK4 was associated with lower pH in PSE samples (pH[PSE] = 5.59M-BM-10.09, pH[normal] = 5.77M-BM-10.17). The RNAseq results provided a greater molecular mechanistic understanding of development of PSE turkey, which will be a foundation for new intervention strategies to prevent development of this defect. The mRNA profiles of normal and PSE turkey breast muscle were generated by deep sequencing using Illumina GAIIx platform. Multiplexing was performed (2 samples/lane). Afterwards, difference in gene expression between normal and PSE samples were tested.
Project description:The success of turkey breeding for rapid growth rate and larger breast size has coincided with an increasing incidence of a meat quality defect described as pale, soft and exudative (PSE). We hypothesized that this defect, which is associated with an abnormally rapid rate of postmortem metabolism, derives from altered expression of genes involved in metabolic regulation. Our objective was to use deep transcriptome RNA sequence analysis (RNAseq) to identify differentially expressed genes between normal and PSE turkey breasts. Following harvest of turkey breasts (n = 43), the pH at 15 min post-slaughter and percent marinade uptake at 24h post-slaughter were determined. Breast samples were classified as normal or PSE based on marinade uptake (high = normal; low = PSE). Total RNA from samples with the highest (n=4) and lowest (n=4) marinade uptake were isolated and sequenced using the Illumina GAIIX platform. Of 21,340 gene loci discovered by RNAseq, 8480 loci completely matched the turkey reference genome, and 480 genes were differentially expressed (false discovery rate, FDR<0.05) between normal and PSE samples. Two highlights were the genes nephroblastoma overexpressed (NOV), upregulated about 38-fold and pyruvate dehydrogenase kinase isoform 4 (PDK4), downregulated 14-fold in PSE samples. Pathway analysis suggested that several biological functions, including carbohydrate metabolism and energy production, were affected by meat quality. Because PDK4 regulates conversion of pyruvate to acetyl CoA, differences in regulation of oxidative metabolism may exist among turkeys. Accelerated early postmortem metabolism would result in faster pH decline in PSE meat. This hypothesis was supported by the fact that decreased expression of PDK4 was associated with lower pH in PSE samples (pH[PSE] = 5.59±0.09, pH[normal] = 5.77±0.17). The RNAseq results provided a greater molecular mechanistic understanding of development of PSE turkey, which will be a foundation for new intervention strategies to prevent development of this defect.
Project description:The objective of this study was to determine differential gene expression of turkey breast muscle regarding development of PSE meat defect. Genetically unimproved, random-bred (RBC2) turkeys representing turkeys from 1966, which are smaller and grow slower than modern turkeys, were raised at the Michigan State University (MSU) Poultry farm and harvested at 22 week of age. Breast meat was collected and snap frozen in liquid nitrogen. Percent marinade uptake at 24h post-slaughter of each sample was determined. The highest (n=6) and the lowest (n=6) marinade uptake were classified as normal and PSE, respectively. Differentially expressed genes between normal and PSE was identified using TSMLO microarray and confirmed by qRT-PCR. Forty-one oligos were differentially expressed (false discovery rate, FDR<0.1). Candidate genes and pathways associated with development of PSE in turkey were suggested for further experiment to gain greater comprehension about this meat quality defect. Two-condition experiment: normal vs PSE; Biological replicate: n=6 for each condition; Birds were randomly assigned to an array and hybridizations were performed in random order.
Project description:The objective of this study was to determine differential gene expression of turkey breast muscle regarding development of PSE meat defect. Genetically unimproved, random-bred (RBC2) turkeys representing turkeys from 1966, which are smaller and grow slower than modern turkeys, were raised at the Michigan State University (MSU) Poultry farm and harvested at 22 week of age. Breast meat was collected and snap frozen in liquid nitrogen. Percent marinade uptake at 24h post-slaughter of each sample was determined. The highest (n=6) and the lowest (n=6) marinade uptake were classified as normal and PSE, respectively. Differentially expressed genes between normal and PSE was identified using TSMLO microarray and confirmed by qRT-PCR. Forty-one oligos were differentially expressed (false discovery rate, FDR<0.1). Candidate genes and pathways associated with development of PSE in turkey were suggested for further experiment to gain greater comprehension about this meat quality defect.