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Nieinwazyjne strategie w monitorowaniu stanu zdrowia zwierząt. Badania nad przydatnością alternatywnych matryc w diagnostyce, epidemiologii i ocenie statusu immunologicznego na modelu świni domowej (Sus scrofa domestica)
Concentrations of selected immunological parameters in the serum and processing fluid of suckling piglets and the serum and colostrum of their mothers
Abstract 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.
Evaluation of the utility of testicular-only processing fluid for porcine reproductive and respiratory syndrome virus diagnostics and the effect of sample pooling on the test results
Abstract Introduction The testicular-only processing fluid (TOPF) obtained from piglet testicles after castration could be an alternative sample for porcine reproductive and respiratory syndrome (PRRS) laboratory diagnosis. If this matrix were proved useful, testing it would spare piglets the stress of blood drawing and eliminate some labour required to take blood samples. The aim of the study was to evaluate the utility of TOPF for this diagnostic purpose. Material and Methods Serum-and-TOPF pairs from male piglets and sera from female piglets were tested using commercial ELISA and real-time RT-PCR kits. For the pooling simulation, 10 μL aliquots of TOPF separated into low-, moderately and highly positive were mixed with appropriate volumes of negative TOPF samples. This simulated pools of 5, 10, 20, 40 and 80 samples containing 1 positive for serological analyses and pools of 10, 20, 40, 80, 160 and 320 samples containing 1 positive in molecular analyses. Results The percentages of anti-porcine reproductive and respiratory syndrome virus (PRRSV) antibodies were statistically significantly different (P-value < 0.05) between boar sera (69.55%) and TOPF (54.49%), as well as between gilt sera (74.52%) and TOPF. However, after adjusting the cut-off value, no significant differences were noted. The RNA of PRRSV was detected in 21.26% of male sera, 15.23% of TOPFs and 17.00% of female sera. Pooled sample testing revealed discrepancies in positive results associated with the pool size and original sample positivity strength. Conclusion TOPF samples can be a valuable matrix for laboratory PRRS diagnosis in piglets. However, it is important to be aware of the potential for false-negative results.
Field study on the utility of fluid obtained from testicles as a sample for detecting antibodies to selected swine pathogens
Abstract Processing fluid is a promising alternative to blood for monitoring porcine diseases, although certain aspects of its routine use remain unclear. This study evaluated serum from females and males, along with corresponding testicular only processing fluid, for antibodies against Actionbacillus pleuropneumonie, hepatitis E virus, porcine epidemic diarrhea virus, influenza A virus, Erysipetothrix rhusiopathie and Mycoplasma hyopneumoniae, using commercial ELISAs (ID Screen APP, Hepatitis E, PEDV, Influenza A from ID Vet, France; Civtest suis SE/MR from Hipra, Spain; and Mycoplasma hyopneumoniae from Idexx, USA). Differences in the proportion of positive results across sample types were analysed to assess the utility of testis-derived processing fluid for litter-level health monitoring. ROC analysis was used to establish optimal cut-offs for processing fluid, followed by evaluation of diagnostic performance using both manufacturer-recommended and ROC-derived thresholds. A pooling simulation was also performed. Results indicate that processing fluid collected exclusively from testes can detect antibodies against selected pathogens effectively. Some ELISA kits validated for serum may be applicable to processing fluid, provided that appropriate cut-off values are determined for this sample type. However, pooling processing fluid samples may reduce sensitivity and increase the risk of false-negative results. These findings highlight the potential of testis-derived processing fluid for large-scale serological surveillance while underscoring the need for test-specific validation.