Project description:Lactococcus piscium strain MKFS47 is a psychrotrophic spoilage lactic acid bacterium, isolated from the cold-stored modified atmosphere packaged broiler filet strips with the first signs of spoilage. For the experiment L. piscium MKFS47 was grown in MRS broth without acetate with 2% glucose, samples were taken at 3h, 5h and 11h in three replicates. The extracted RNA was sequenced using SOLiD 5500XL. RNA-seq reads were mapped against L. piscium MKFS47 genome and were counted per gene using Lifescope software. The experiment was conducted to identify the time-course differential expression of the L. piscium MKFS47 genes.
Project description:Oxygen and carbon dioxide are common protective gases used in modified atmosphere packaging (MAP) of meat. Within the package, they selectively suppress members of the spoilage microbiome, reshaping it to adapted species concomitantly growing upon MAP. Thus, this species must exhibit adaptation mechanisms to withstand the inhibitory effect of carbon dioxide and oxygen, and cope with selective nutrition on MAP meat. In order to uncover these mechanisms, the typical representative meat-spoiling bacteria Brochothrix (B.) thermosphacta TMW2.2101 and four lactic acid bacteria (LAB) Carnobacterium (C.) divergens TMW2.1577, C. maltaromaticum TMW2.1581, Leuconostoc (L.) gelidum subsp. gelidum TMW2.1618 and L. gelidum subsp. gasicomitatum TMW2.1619 were grown in a meat simulation medium under a controlled, sterile environment, aerated constantly with either air, 100%_N2, 30%_CO2/70%_O2 or 30%_CO2/70%_N2. Growth dynamics were monitored and a label-free quantitative mass spectrometric approach was employed to determine changes within the bacterial proteomes in response to the different gas atmospheres. Revealed bacterial tolerance to modified atmospheres (MA) comprise two possible scenarios: Either bacteria were intrinsically adapted to MA, exhibiting no proteomic regulation of enzymes (L. gelidum subsp. gelidum and gasicomitatum) or, tolerance was provided by varying specific metabolic adaptation (B. thermosphacta, C. divergens, C. maltaromaticum). In detail, metabolic adaptation mechanisms to oxygen comprised an enhanced oxidative stress reduction response, adjustment of the pyruvate metabolism and catabolic oxygen consuming reactions. Adaptation to carbon dioxide was characterized by an upregulation of proteins involved in intracellular pH homeostasis, maintenance of osmotic balance and alteration of the fatty acid composition of the cell membrane. We furthermore predict species-specific strategies for different and preferential carbon source utilization enabling a non-competitive coexistence on meat and resulting in a synergistic spoilage. We conclude that a gas atmosphere containing 30%_CO2/70%_O2 has no inhibitory effect on the analyzed prominent meat-spoiling bacteria whereas 30%_CO2/70%_N2 predictively inhibits C. divergens TMW21577 and B. thermosphacta TMW2.2101 but not the other three species. This gives a mechanistically explanation of their acknowledged status as typical spoilage organisms on packaged meats.
Project description:Optimization of broiler chicken breast muscle protein accretion is key for the efficient production of poultry meat, whose demand is steadily increasing. In a context where antimicrobial growth promoters use is being restricted, it is important to find alternatives as well as to characterize the effect of immunological stress on broiler chicken growth. Despite of its importance, research on broiler chicken muscle protein dynamics has been mostly limited to the study of mixed protein turnover. The present study aims to characterize the effect of a bacterial challenge and the feed supplementation of a citrus and a cucumber extract on broiler chicken individual breast muscle proteins fractional synthesis rates (FSR) using a recently developed dynamic proteomics pipeline. 21 day-old broiler chickens were administered a single 2H2O dose before being culled at different timepoints. A total of 60 breast muscle protein extracts from five experimental groups (Unchallenged, Challenged, Control Diet, Diet 1 and Diet 2) were analyzed using a DDA proteomics approach. Proteomics data was filtered in order to reliably calculate multiple proteins FSR making use of a newly developed bioinformatics pipeline. Broiler breast muscle proteins FSR uniformly decreased following a bacterial challenge, this change was judged significant for 15 individual proteins, the two major functional clusters identified as well as for mixed breast muscle protein. Citrus or cucumber extract feed supplementation did not show any effect on the breast muscle protein FSR of immunologically challenged broilers. The present study has identified potential predictive markers of breast muscle growth and provided new information on broiler chicken breast muscle protein turnover which could be essential for improving the efficiency of broiler chicken meat production.
Project description:Proteomic analysis was performed on the proximal tibia head from healhty and BCO-affected broiler (meat-type) chickens using Bruker Daltonics amaZon series Mass Spectrometer. This analysis was undertaken to identify key protein signature involved in BCO, a common cause of lameness.
Project description:Abstract: Ammonia is one of the most prominent air pollutants in poultry houses. High levels of ammonia have adverse effects on respiratory health, growth performance, meat production of broilers, and breast meat growth and yield are critical important in the broiler industry. To date, studies focus on the negative relationship of ammonia exposure and breast muscle tissue are still very limited, and the underlying molecular mechanisms remain poorly understood. In this study, high concentrations of atmospheric ammonia were found to lower slaughter rate and broiler breast meat yield significantly (P < 0.05). To explore the candidate genes that ammonia regulates breast meat yield of broilers, high throughout RNA-Seq was used to compare the transcriptome of breast muscle with different ammonia exposure (50 ppm vs 3 ppm). In total, 129 differentially expressed genes (DEGs) were identified (P-value < 0.05; fold-change ≥ 2), among which 87 genes were significantly down-regulated and 42 were up-regulated. Bioinformatics analysis suggested that DEGs (such as PDK4, ACSL1, GLUL, FBXO32) were involved in fatty acid degradation/metabolism, nitrogen metabolism, PPAR signaling and adipocytokine signaling pathways. Functional annotation showed that DEGs were mainly enriched in reactive oxygen species metabolic process and muscle contraction. It can be concluded that decreased meat yield was due to the DEGs participating in above biological processes and pathways. This study provides novel insights into transcriptional differences in breast meat between high- and low-ammonia exposed broiler chickens.
Project description:This study applied peptidomics to investigate potential biomarkers for evaluating pork-meat freshness. Meat samples stored at -2, 4, 10, and 25 °C were collected at specific time points to evaluate meat freshness indicators (color, total viable count, pH, and total volatile basic nitrogen). The sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) profile was analyzed, and substantial protein degradation (myosin heavy chain, paramyosin, troponin) was detected at the end of storage, regardless of the temperature. Peptidomics analysis was performed using a UHPLC-LTQ-Orbitrap mass spectrometer, and the potential peptide marker MVHMASKE was filtered via multivariate analysis and quantified by parallel reaction monitoring combined with external standard quantitation. In addition, the relationship between peptide content and change in meat freshness was verified using real-life samples and the content of MVHMASKE showed an obvious decline during storage, presenting a period of pork meat from fresh to spoilage. This study provides favorable evidences to evaluate pork meat freshness by mass spectrometry-based pep-tidomics.