Meat juice: An alternative matrix for assessing animal health by measuring acute phase proteins. Correlations of pig-MAP and haptoglobin concentrations in pig meat juice and plasma

Concentrations of selected immunological parameters in the serum and processing fluid of suckling piglets and the serum and colostrum of their mothers

BACKGROUND

Blood sampling from neonatal piglets is related to multiple disadvantages. Therefore, a new, alternative matrix is required to assess piglets' early immune status efficiently. The present study aimed to assess the usefulness of processing fluid for determining selected piglets' immune parameters. 264 pigs - 31 sows, 146 male piglets, and 87 female piglets from commercial indoor farrow-to-finish pig herd were included in this study. 264 serum, 31 colostrum, and 146 processing fluid samples were collected. Serum was collected from all animals, colostrum was collected from sows, and processing fluid was collected from male piglets only. Using commercial ELISA tests, the concentration of various immunoglobulins, cytokines, and acute phase proteins was assessed in each matrix. Statistical analyses were employed to determine differences in the concentration of measured indices between piglets' serum and processing fluid and correlations in the concentration of tested indices between particular sets of matrices.

RESULTS

Statistical analyses did not reveal significant differences in the IgG, IgA, IL-1β, IL-4, IL-6, and IFN-γ concentration between piglets' serum and processing fluid (p > 0.05). A positive correlation (p < 0.05) regarding the concentration of some indices between processing fluid and samples collected from sows was also observed.

CONCLUSIONS

Processing fluid can be considered a promising alternative to blood for assessing some immunological indices in piglets, such as IgG, IgA, IL-1β, IL-4, IL-6, and IFN-γ, and, possibly, in the indirect assessment of some indices in lactating sows, including IgA, IL-1β, IL-4, IL-6, IL-8, IFN-γ, or Pig-MAP.

Proteomic methods for the study of porcine acute phase proteins - anything new to detect?

Acute phase proteins (APPs) reflect the health status of individuals and are important tools in diagnostics, as their altered levels are a sign of disturbed homeostasis. While, in most cases, quantitation of known serum APPs is routinely performed by immunoassays, proteomics is helpful in discovery of new biomarker candidates, especially in samples other than body fluids. Besides putting APP regulation into an overall context of differentially abundant proteins, this approach can detect further details or outright new features in protein structure or specific modifications, and help understand better their function. Thus, it can show up ways to make present diagnostic assays more sensitive and/or specific, or correlate regulations of disease-specific proteins. The APP repertoire is dependent on the species. The pig is both, an important farm animal and a model animal for human diseases, due to similarities in physiology. Besides reviewing existing literature, yet unpublished examples for two-dimensional electrophoresis in connection with pig APPs highlight some of the benefits of proteomics. Of further help would be the emerging targeted proteomics, offering the possibility to determine particular isoforms or proteoforms, without the need of specific antibodies, but this method is presently scarcely used in veterinary medicine.

Acute phase proteins in cattle and swine: A review

The major acute phase proteins (APPs) in cattle are haptoglobin (Hp) and serum amyloid A (SAA), and in swine, are Hp, SAA, C-reactive protein (CRP), and Pig major acute phase protein (Pig-MAP). Many methodologic assays are presently available to measure these parameters, which are still being improved to increase their specificity, sensitivity, user-friendliness, and economic availability. In cattle, the main applications are the diagnosis and monitoring of frequent diseases such as mastitis and metritis in dairy cows and respiratory problems in young calves. In pigs, APPs are useful in the control of bacterial and viral infections, and they may be used at the slaughterhouse to monitor subclinical pathologies and improve food safety. The utility of APP in animal production must not be forgotten; optimization of protocols to improve performance, welfare, and nutrition may benefit from the use of APPs. Other sample types besides serum or plasma have potential uses; APP determination in milk is a powerful tool in the control of mastitis, saliva is a non-invasive sample type, and meat juice is easily obtained at the slaughterhouse. Increasing our knowledge of reference intervals and the influence of variables such as age, breed, sex, and the season is important. Finally, worldwide harmonization and standardization of analytical procedures will help to expand the use of APPs.

Biosecurity and Lairage Time versus Pork Meat Quality Traits in a Farm-Abattoir Continuum

The modern pig production chain is increasingly focused on biosecurity, quality, and safety of meat and is associated with many challenges impacting world meat markets, such as animal disease outbreaks and sanitary restrictions, trade regulations and quality requirements. To overcome such challenges and assure more consistent pork meat quality (and safety), there is a need to develop an effective and reliable monitoring system in a farm-abattoir continuum that can be based on selected biomarkers. This study assessed interrelations of selected stress and inflammation biomarkers (acute phase proteins (APP)) between farm biosecurity score versus pork meat quality traits after two different lairage periods. Briefly, the maximum recorded levels of stress hormones (436.2 and 241.2 ng/mL, for cortisol and Chromogranin A (CgA), respectively) and APP (389.4 and 400.9 μg/mL, Pig Major Acute Proteins (MAP) and Haptoglobin (Hp), respectively) at four commercial farms were within the recommended threshold values. Cortisol and APP were negatively correlated to the internal and total biosecurity scores of farms. The increase of level of both sets of biomarkers was found at bleeding (after transportation and lairage period), but with lower values after long (18-20 h) versus short (1-3 h) lairage lay-over time. In general, negative correlation was confirmed between stress and inflammation biomarkers and carcass/meat quality traits. The farm total biosecurity level significantly affected chilling yield, meat temperature, and a* value. Pig-MAP emerged as a good biomarker with a promising potential for assessment and anticipation of broad aspects in the pork meat chain. It can be used for detection of failures in the pig production system and might be incorporated in certification programs for the pork meat industry.

Noninvasive strategies for surveillance of swine viral diseases: a review

In view of the intensive development of the swine industry, monitoring and surveillance of infectious diseases require low-cost, effective, and representative population sampling methods. We present herein the state of knowledge, to date, in the use of alternative strategies in the monitoring of swine health. Blood sampling, the most commonly used method in veterinary medicine to obtain samples for monitoring swine health, is labor-intensive and expensive, which has resulted in a search for alternative sampling strategies. Oral fluid (OF) is a good alternative to serum for pooled sample analysis, especially for low-prevalence pathogens. Detection of viral nucleic acids or antiviral antibodies in OF is used to detect numerous viruses in the swine population. Meat juice is used as an alternative to serum in serologic testing. Processing fluid obtained during processing of piglets (castration and tail-docking) may also be used to detect viruses. These matrices are simple, safe, cost-effective, and allow testing of many individuals at the same time. The latest methods, such as snout swabs and udder skin wipes, are also promising. These alternative samples are easy to acquire, and do not affect animal welfare negatively.

Diagnostic accuracy of porcine acute phase proteins in meat juice for detecting disease at abattoir

The aim of this work was to evaluate whether acute phase protein (APP) determinations could assist Official Veterinarians carrying out work in slaughterhouses. To test this hypothesis, the diagnostic accuracy of APP determinations in meat juice of pigs was analysed to differentiate between healthy and diseased pigs. One hundred and one pigs of two different origins were classified into two groups according to their health status (healthy and diseased pigs), which was determined by a veterinary clinical examination on the farm. To assess the pigs' immune status, against the main porcine diseases, serological analyses were monitored. A general idea of the degree of disease coverage was analysed by examining organ lesions postmortem. Haptoglobin (Hp) and C reactive protein (CRP) were measured in meat juice samples. 72.13 per cent of pigs appeared to be seropositive for the porcine respiratory and reproductive syndrome virus, and almost 86.2 per cent of them had concomitant infections with other pathogens, such as Porcine circovirus type 2 or Swine influenza virus. Median Hp and CRP concentrations were significantly higher in diseased animals at different stages of the production chain, when compared with levels found in healthy finishing pigs (P<0.0001). Receiver operating characteristic analysis showed the highest sensitivity-specificity pairs, nearly 80-90 per cent, at cut-off levels of 83 and 10 µg/ml for Hp and CRP determinations, respectively, with high AUCs 0.9. This cut-off could be useful for veterinary inspections at the time of slaughter, to differentiate between the carcase of a healthy animal and the carcase of an animal suffering from a systemic disease, which should be completely condemned.

Detection of porcine circovirus type 2 (PCV2) and porcine reproductive and respiratory syndrome virus (PRRSV) antibodies in meat juice samples from Polish wild boar (Sus scrofa L.)

PCV2 and PRRSV are two important pathogens of domestic swine. There is considerable evidence that the infection is also present in wild boars. Meat juice provides an alternative to serum for antibody testing, and it has been used in testing for many important porcine infectious diseases. Samples of brachial muscle were collected from 142 wild boars shot in different regions of Poland during the 2006/2007 and 2007/2008 hunting seasons. Meat juice harvested from muscle samples was tested using an ELISA test specific for PCV2 and PRRSV antibodies. Additionally, IgG and IgM antibodies specific for PCV2 were detected in order to estimate the status of the PCV2 infection. Only one of the tested meat juice samples was positive for PRRSV (0.7%), and 68 out of 142 (47.9%) samples were positive for PCV2. Of the positive animals, 4 (2.8%) had an antibody profile suggesting active infection, 2 (1.4%) early active infection, and 62 (43.7%) late infection. Also, a lack of association between the age of the animals and the presence of antibodies related to the infection was noticed.

Acute phase proteins in animals

Acute phase proteins (APP) were first identified in the early 1900s as early reactants to infectious disease. They are now understood to be an integral part of the acute phase response (APR) which is the cornerstone of innate immunity. APP have been shown to be valuable biomarkers as increases can occur with inflammation, infection, neoplasia, stress, and trauma. All animals--from fish to mammals--have demonstrable APP, but the type of major APP differs by species. While the primary application of these proteins in a clinical setting is prognostication, studies in animals have demonstrated relevance to diagnosis and detection and monitoring for subclinical disease. APP have been well documented in laboratory, companion, and large animals. With the advent of standardized and automated assays, these biomarkers are available for use in all fields of veterinary medicine as well as basic and clinical research.

Identification of cattle, llama and horse meat by near infrared reflectance or transflectance spectroscopy

Visible and near infrared reflectance spectroscopy (VIS-NIRS) was used to discriminate meat and meat juices from three livestock species. In a first trial, samples of Longissimus lumborum muscle, corresponding to beef (31) llamas (21) and horses (27), were homogenised and their spectra collected in reflectance (NIRSystems 6500 scanning monochromator, in the range of 400-2500 nm). In the second trial, samples of meat juice (same muscle) from the same species (20 beef, 19 llama and 19 horse) were scanned in folded transmission (transflectance). Discriminating models (PLS regression) were developed against "dummy" variables, testing different mathematical treatments of the spectra. Best models indentified the species of almost all samples by their meat (reflectance) or meat juice (transflectance) spectra. A few (three of beef and one of llama, for meat samples; one of beef and one of horse, for juice samples) were classified as uncertain. It is concluded that NIRS is an effective tool to recognise meat and meat juice from beef, llama and horses.

Haptoglobin and C-reactive protein as biomarkers in the serum, saliva and meat juice of pigs experimentally infected with porcine reproductive and respiratory syndrome virus

Concentrations of the acute phase proteins haptoglobin (Hp) and C-reactive protein (CRP) were measured in the serum, saliva and meat juice of pigs experimentally infected with a porcine reproductive and respiratory syndrome virus (PRRSv) field isolate. Sixteen PRRSv-free pigs were inoculated IM, killed in groups of four at 7, 14, 21 and 24 days post-inoculation (dpi), and samples of blood, saliva and diaphragmatic muscle were collected. Four non-infected controls were killed at 24 dpi. Significant differences in lung lesions were found between PRRSv-inoculated animals and controls. Changes in the concentrations of Hp and CRP in serum, saliva and meat juice samples were similar, peaking at 21 dpi. The correlations found suggest that the measurement of Hp and CRP in saliva and meat juice could serve as complementary, or possibly alternative, biomarkers of pig herd-health.