Can Procalcitonin Be Dosed in Bovine Milk Using a Commercial ELISA Kit?
by
, , , and
Valentina Meucci
1
,
Chiara Orsetti
1,2, 
Micaela Sgorbini
1,2,
Federica Battaglia
1,
Marta Cresci
1
and
Francesca Bonelli
1,2,*
1
Department of Veterinary Science, University of Pisa, Via Livornese snc, 56122 Pisa, Italy
2
Centro di Ricerche Agro-Ambientali “E. Avanzi”, University of Pisa, Via Vecchia di Marina 6, 56122 Pisa, Italy
*
Author to whom correspondence should be addressed.
Animals 2022, 12(3), 289; https://doi.org/10.3390/ani12030289
Submission received: 31 December 2021
/
Revised: 20 January 2022
/
Accepted: 24 January 2022
/
Published: 25 January 2022
(This article belongs to the Special Issue New Microbiological, Clinical and Management Features for Improving the Udder Health and Milk Quality in Animals)
Simple Summary
Mastitis is one of the major economic and animal welfare problems on dairy farms. The gold standard test for mastitis diagnosis is milk culture, but bacteria are not always isolated (only in 11–44% of milk samples from clinical cases of mastitis) and sometimes a positive culture can result from a contamination of the milk. Procalcitonin is a new biomarker which may lead to an early detection of inflammation due to bacterial infection. In humans, procalcitonin concentration has also been evaluated in milk in addition to plasma. The authors aimed to evaluate the possible application of a commercially available ELISA kit for bovine procalcitonin for the assessing of procalcitonin in bovine milk samples. Plasma and milk samples from cows with mastitis were collected to measure procalcitonin concentrations by using a bovine procalcitonin ELISA kit. Our results showed that the ELISA kit tested can be employed to assess bovine procalcitonin in plasma but not for analyzing milk samples.
Abstract
The aim was to evaluate the use of a bovine procalcitonin (PCT) ELISA kit (Cusabio, China) for assessing PCT in bovine milk samples. Validation was performed by using 10 plasma and corresponding milk samples from mastitic cows. The limit of detection (LOD) was calculated. The coefficient of variation (CV%) of the readings of five plasma samples measured five times in the same plate (intra-assay) and the CV% of the same five samples read five times in three separate plates was evaluated. Parallelism was determined by serial twofold dilutions of five plasma and corresponding milk samples. Milk samples were analyzed with and without centrifugation. Regarding plasma PCT, the method presented an inter- and intra-CV < 23.7% and parallelism had very good recovery values. The ELISA kit studied can measure bovine plasma PCT concentrations. The kit antibodies fail in binding PCT in milk samples because all centrifuged milk samples showed a lower LOD than blank samples. Only three uncentrifuged milk samples showed measurable PCT concentrations. Due to these results, the commercial ELISA kit investigated could not be employed for the detection of PCT in milk samples.
