Development and validation of miRNA based method for rapid identification of offal meats in processed chicken meat products

Exosomal miR-27a-5p attenuates inflammation through Toll-like receptor 7 in foodborne Salmonella infections

Salmonella is a common food-borne pathogen that is highly pathogenic and infectious, causing serious harm to livestock breeding and food safety. Uncovering the mechanisms of Salmonella infection and immune evasion can effectively prevent Salmonella contamination of livestock and poultry food. Here, small RNA sequencing results showed that exosomes produced by naïve murine macrophages RAW 264.7 cells contained a unique enrichment of a set of microRNAs (miRNAs) after Salmonella infection. Quantitative real-time polymerase chain reaction (qPCR) analysis verified that the tested miRNA (i.e. miR-27a-5p, miR-92a-1-5p and miR-1249-5p) showed similar expression patterns, consistent with small RNA sequencing data. TargetScan database predicted that the most promising targets for the differentially expressed miRNAs were abundant in the immune system, infectious diseases, and signal transduction pathways. Dual-luciferase reporter assays confirmed that Toll-like receptor 7 (TLR7) was the target of miR-27a-5p. Western blotting and enzyme-linked immunosorbent assay (ELISA) results revealed that overexpression of miR-27a-5p suppressed inflammation by targeting TLR7/nuclear factor kappa-B (NF-κB) signaling pathway and leading interleukin-6 (IL-6) and IL-1β cytokines slightly reduction in recipient macrophages, suggesting that exosomal miR-27a-5p uptake by naïve macrophages may inhibit pro-inflammatory macrophage differentiation. Therefore, these results contribute to our systematic understanding of the mechanism of exosomal miRNA in Salmonella infection, providing a potential target for preventing immune escape from Salmonella.

Absolute quantification of targeted rabbit liver- and meat tissue-specific peptide markers in highly processed food products

A highly sensitive and selective method for the simultaneous absolute quantification of peptides unique to rabbit meat- and liver-specific tissue was developed using liquid chromatography - triple quadrupole mass spectrometry. Two rabbit skeletal muscle-specific peptides (SSVFVADPK and PHSHPALTPEQK), three rabbit liver tissue-specific peptides (FNLEALVTHTLPFEK, AILNYVANK, and TELAEPTSTR) and one peptide specific to both rabbit offal and skeletal muscle tissue (AFFGHYLYEVAR) were monitored. Analyses were performed using peptides labelled with stable isotopes (13C and 15N) as internal standards. Fifteen food samples containing rabbit meat and/or liver were analysed to verify compliance of the rabbit meat and liver composition with product labelling. One sample was adulterated with undeclared rabbit liver. The limit of detection and limit of quantification for the selected peptides of interest were in the range of 0.17 to 0.35 ng/mg and 0.57 to 1.17 ng/mg, respectively. The method may be useful for the determination of rabbit meat and liver tissue in highly processed food samples.

miRNAs as Biomolecular Markers for Food Safety, Quality, and Traceability in Poultry Meat-A Preliminary Study

In this study, the expression and abundance of two candidate chicken (Gallus gallus; gga) microRNAs (miRNAs, miR), gga-miR-21-5p (miR-21) and gga-miR-126-5p (miR-126), have been analyzed in order to identify biomarkers for the traceability and quality of poultry meat. Two breeds of broiler chickens were tested: the most common Ross308 (fast-growing) and the high-quality Ranger Gold (slow-growing). A preliminary analysis of the two miRNAs expressions was conducted across various tissues (liver, lung, spleen, skeletal muscle, and kidney), and the three tissues (lung, spleen, and muscle) with a higher expression were chosen for further analysis. Using quantitative reverse transcription polymerase chain reaction (RT-qPCR), the expression of miRNAs in the three tissues of a total of thirteen animals was determined. The results indicate that miR-126 could be a promising biomarker for the lung tissue in the Ranger Gold (RG) breed (p < 0.01), thus suggesting a potential applicability for tracing hybrids. RG exhibits a significantly higher miR-126 expression in the lung tissue compared to the Ross308 broilers (R308), an indication of greater respiratory capacity and, consequently, a higher oxidative metabolism of the fast-growing hybrid. During sampling, two R308 broilers presented some anomalies, including airsacculitis, hepatic steatosis, and enlarged spleen. The expression of miR-126 and miR-21 was compared in healthy animals and in those presenting anomalies. Chickens with airsacculitis and hepatic steatosis showed an up-regulation of miR-21 and miR-126 in the most commercially valuable tissue, the skeletal muscle or breast (p < 0.05).

Heat-stable peptide markers specific to rabbit and chicken liver tissue for meat product authentication testing

A three-step analysis was used to detect and identify heat-stable peptide markers specific to liver tissue from rabbit and chicken. It involved peptide discovery by liquid chromatography coupled to high resolution mass spectrometer (LC-HRMS), followed by protein identification using Spectrum Mill software and multiple reaction monitoring (MRM) based confirmation of the discovered peptides using a liquid chromatography coupled to triple quadrupole mass spectrometer (LC-TQ). We identified 50 and 91 heat-stable peptide markers unique to chicken and rabbit liver, respectively. The markers were validated in commercial food samples with declared liver tissue contents ranging from 5% to 30%. The best candidate peptides for distinguishing liver tissue from skeletal muscle were selected and then confirmed using MRM-based approach. Limit of detection of liver was found to be in the range of 0.13 to 2.13% (w/w) for chicken liver-specific peptide markers, and from 0.04 to 0.6% (w/w) for rabbit liver-specific peptide markers.

High-performance triplex PCR detection of three tapeworm species belonging to the genus Raillietina in infected poultry

Chickens and ducks are important sources of essential proteins and nutrition for global consumption, especially their eggs and meat. Tapeworm infections in chickens and ducks are the cause of serious poultry health and economic problems in the processing of livestock and food production systems. Raillietina are cosmopolitan in distribution and are possibly the most common tapeworm parasites. There are three important species regarding avian infection, with different pathogenicity, including Raillietina echinobothrida, R. tetragona, and R. cesticillus. Co-infection diagnosis of these tapeworms using morphological analysis can be performed, but this is time-consuming and complicated. Therefore, this study aimed to develop a triplex PCR for the detection and discrimination of three Raillietina species. The triplex PCR assay specifically amplified target DNAs with no inter-specific interference and produced a specific band for each species. According to the specificity test, there was no cross-amplification with the DNA template of related parasites and their hosts. The lowest detectable DNA concentrations were evaluated and provided sensitivities of 0.5 pg/μL for R. echinobothrida, 5 pg/μL for R. tetragona, 50 fg/μL for R. cesticillus, and 5 pg/μL for the combination of DNA from all three species. Simultaneous detection limits of egg capsules and gravid proglottids was also performed, with and without feces. The interference of feces in the reaction was related to a decrease in sensitivity, but simultaneous detection of three Raillietina species in amounts lower than one gravid proglottid and ten egg capsules was still successful. Thus, this study is the first triplex PCR assay for Raillietina detection and can be utilized as an alternative diagnostic tool for the detection and discrimination of R. echinobothrida, R. tetragona, and R. cesticillus infection in poultry through the verification of fecal specimens. In addition, it could improve the performance of specific treatments and promote veterinary healthcare.

Omics-Based Analytical Approaches for Assessing Chicken Species and Breeds in Food Authentication

Chicken is known to be the most common meat type involved in food mislabeling and adulteration. Establishing a method to authenticate chicken content precisely and identifying chicken breeds as declared in processed food is crucial for protecting consumers' rights. Categorizing the authentication method into their respective omics disciplines, such as genomics, transcriptomics, proteomics, lipidomics, metabolomics, and glycomics, and the implementation of bioinformatics or chemometrics in data analysis can assist the researcher in improving the currently available techniques. Designing a vast range of instruments and analytical methods at the molecular level is vital for overcoming the technical drawback in discriminating chicken from other species and even within its breed. This review aims to provide insight and highlight previous and current approaches suitable for countering different circumstances in chicken authentication.