Identification of novel biomarkers of acute phase response in chickens challenged with Escherichia coli lipopolysaccharide endotoxin.

BACKGROUND: The chicken's inflammatory response is an essential part of the bird's response to infection. A single dose of Escherichia coli (E. coli) lipopolysaccharide (LPS) endotoxin can activate the acute phase response (APR) and lead to the production of acute phase proteins (APPs). In this study, the responses of established chicken APPs, Serum amyloid A (SAA) and Alpha-1-acid-glycoprotein (AGP), were compared to two novel APPs, Hemopexin (Hpx) and Extracellular fatty acid binding protein (Ex-FABP), in 15-day old broilers over a time course of 48 h post E.coli LPS challenge. We aimed to investigate and validate their role as biomarkers of an APR. Novel plant extracts, Citrus (CTS) and cucumber (CMB), were used as dietary supplements to investigate their ability to reduce the inflammatory response initiated by the endotoxin. RESULTS: A significant increase of established (SAA, AGP) and novel (Ex-FABP, Hpx) APPs was detected post E.coli LPS challenge. Extracellular fatty acid binding protein (Ex-FABP) showed a similar early response to SAA post LPS challenge by increasing ~ 20-fold at 12 h post challenge (P < 0.001). Hemopexin (Hpx) showed a later response by increasing ∼5-fold at 24 h post challenge (P < 0.001) with a similar trend to AGP. No differences in APP responses were identified between diets (CTS and CMB) using any of the established or novel biomarkers. CONCLUSIONS: Hpx and Ex-FABP were confirmed as potential biomarkers of APR in broilers when using an E. coli LPS model along with SAA and AGP. However, no clear advantage for using either of dietary supplements to modulate the APR was identified at the dosage used.

A novel dynamic proteomics approach for the measurement of broiler chicken protein fractional synthesis rate.

RATIONALE: The study of protein synthesis in farm animals is uncommon despite its potential to increase knowledge about metabolism and discover new biomarkers of health and growth status. The present study describes a novel dynamic proteomics approach for the measurement of protein fractional synthesis rate (FSR) in broiler chickens. METHODS: Chickens received a 10 g/kg oral dose of 2 H2 O at day 21 of their life. Body water 2 H abundance was measured in plasma samples using a portable Fourier transform infrared spectrometer. Free and protein-bound amino acids (AAs) were isolated and had their 2 H enrichment measured by gas chromatography with mass spectrometry (GC/MS). Peptide 2 H enrichment was measured by proteomics analysis of plasma and muscle samples. Albumin, fibrinogen and muscle protein FSR were calculated from GC/MS and proteomics data. RESULTS: Ala appeared to be more enriched at the site of protein synthesis than in the AA free pools. Glu was found to be the AA closest to isotopic equilibrium between the different AA pools. Glu was used as an anchor to calculate n(AA) values necessary for chicken protein FSR calculation in dynamic proteomics studies. FSR values calculated using proteomics data and GC/MS data showed good agreement as evidenced by a Bland-Altman residual plot. CONCLUSIONS: A new dynamic proteomics approach for the measurement of broiler chicken individual protein FSR based on the administration of a single 2 H2 O oral bolus has been developed and validated. The proposed approach could facilitate new immunological and nutritional studies on free-living animals.

Measuring the impact of dietary supplementation with citrus or cucumber extract on chicken gut microbiota using 16s rRNA gene sequencing.

This study investigated the effects of dietary supplements, citrus (CTS) and cucumber (CMB), on the jejunum and cecum microbiota of 14- and 28-days old broiler chickens to evaluate their impact on the gut health and assess their role as alternatives to antibiotic growth promoters (ABGPs). 16SrRNA gene sequencing revealed the overall bacterial microbiota composition was significantly affected by the gut site (p?

Effect of an immune challenge and two feed supplements on broiler chicken individual breast muscle protein synthesis rate.

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's growth. Despite its importance, research on broiler chicken muscle protein dynamics has mostly been 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 citrus and cucumber extracts on broiler chicken individual breast muscle proteins fractional synthesis rates (FSR) using a recently developed dynamic proteomics pipeline. Twenty-one 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 analysed 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 synthesis which could be essential for improving the efficiency of broiler chicken meat production. SIGNIFICANCE: The present study constitutes the first dynamic proteomics study conducted in a farm animal species which has characterized FSR in a large number of proteins, establishing a precedent for biomarker discovery and assessment of health and growth status. Moreover, it has been evidenced that the decrease in broiler chicken breast muscle protein following an immune challenge is a coordinated event which seems to be the main cause of the decreased growth observed in these animals.