Determination of diagnostic value of milk Amyloid A as a new biomarker of bulk milk quality

Subject Areas : clinical veterinary science

M.R.  Taghdiri, ¹ (Department of Pathobiology, Faculty of Specialized Veterinary Sciences, Science and Research Branch, Islamic Azad University, Tehran, Iran)
گیتی  Karim, ² (Department of food Hygiene and control, Faculty of veterinary Medicine, Tehran, Iran)
شهاب الدین  Safi ³ (Department of Pathobiology, Faculty of Specialized Veterinary Sciences, Science and Research Branch, Islamic Azad University, Tehran, Iran)
A.  Rahimi Froushani, ⁴ (Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran)
A.A  Motalebi ⁵ (Department of Hygiene, Faculty of Specialized Veterinary Sciences, Science and Research Branch, Islamic Azad University, Tehran, Iran)

Received: 2016-11-03 Accepted : 2016-11-03 Published : 2013-06-22

Keywords: milk quality, biomarker, Milk Amyloid A,

Abstract :

Somatic cell count (SCC) has been considered as the golden standard method to evaluate raw bulk milk quality forseveral decades. Nevertheless, SCC is neither sensitive nor specifc enough to evaluate raw bulk milk. Much efforthas been performed to substitute new markers in this regard. Acute phase proteins (APPs) as part of inflammatoryresponse received too much attention as new diagnostic markers in veterinary medicine as well as subclinicalmastitis in dairy cattle. Since subclinical mastitis cause unfavorable changes in milk composition, APPs wouldbe a potential biomarkers to predict milk quality. The objectives of this study were to determine the diagnosticvalue of Milk Amyloid A(MAA) for evaluating raw bulk milk quality delivered to dairy industry and to establishcut off points to detect early changes in bulk tank milk quality. The study performed on 30 random selected dairyfarms delivering their bulk milk to Pegah dairy industries at Tehran province. Three milk samples collected at3 different times to measure MAA, SCC, total protein, casein, total fat and lactose level using commerciallyavailable methods. Diagnostic sensitivity and specifcity and cutoff points for each test were determined usingreceiver-operating characteristics (ROC) analysis. MAA was the most accurate test with a diagnostic sensitivityof 96% and specifcity of 60% at cutoff point of 55.64ng/mL based on a SCC of 200 × 1000 cells/mL of bulkmilk. The study showed that determination of MAA can be used as a potential biomarker to discriminate earlyunfavorable compositional change in bulk milk quality based on SCC higher than 200 × 1000 cells/mL of bulkmilk. A signifcant relationship found between MAA and bulk milk protein quality traits(P<0.05).