Milk protein profiles in response to Streptococcus agalactiae subclinical mastitis in dairy cows

Abstract

The objective of this study was to investigate the milk protein profiles of normal milk and those of milk during the course of subclinical mastitis, caused by natural Streptococcus agalactiae infection. Two-dimensional gel electrophoresis and liquid chromatography mass spectrometry were used to assess protein profiles and to identify the proteins. The results showed that S. agalactiae subclinical mastitis altered the protein profiles of milk. Following Mascot database matching, 11 and 12 protein types were identified in the milk collected from healthy and S. agalactiae subclinical mastitic udders, respectively. The distinct presence of the antibacterial protein cathelicidin-1 was detected in infected milk samples, which in turn was highly correlated to the severity of subclinical mastitis as represented by the milk somatic cell count (r = 0.616), but not the bacterial count. The protein profile of milk reveals changes in the host response to S. agalactiae intramammary infection; cathelicidin-1 could therefore serve as a biomarker for the detection of subclinical mastitis in dairy cows.

Transcriptomics and iTRAQ-Proteomics Analyses of Bovine Mammary Tissue with Streptococcus agalactiae-Induced Mastitis

“…Cathelicidin-1 has been detected in milk from cows naturally infected with S. agalactiae , but not in normal milk samples, and various cathelicidins possess anti- S. agalactiae activity . In this study, CAMP was up-regulated in the S. agalactiae group, which supports previous results reported in the literature. , …”

“…22 Cathelicidin genes are expressed by activated bovine neutrophils and in mammary tissues from cows having milk SCC > 1 000 000 cells/mL. 23 Cathelicidin-1 has been detected in milk from cows naturally infected with S. agalactiae, but not in normal milk samples, 24 and various cathelicidins possess anti-S. agalactiae activity. 23 In this study, CAMP was upregulated in the S. agalactiae group, which supports previous results reported in the literature.…”

Review: Proteomic approaches to control lactational parameters in dairy cows

“…Although the initial discovery was made with a proteomic approach in ovine mammary epithelial cells following S. uberis mastitis, subsequent investigation of bovine mastitis using an immunoassay with an antibody to synthetic pan-cathelicidin peptides has shown that the cathelicidin in milk is highly correlated to somatic s83 cell count the currently favoured test for mastitis, in over 500 milk samples used in validation studies. Cathelicidin has also been identified as a biomarker in Streptococcus agalactiae caused cases of mastitis, although by use of the classic proteomic method of two-dimensional electrophoresis along with MS (Pongthaisong et al, 2016).…”

Short communication: Characterization of the milk protein expression profiles in dairy buffaloes with and without subclinical mastitis

“…In dairy animals, proteomics has widely been used to analyze the milk fat globule membrane proteins (Lu et al, 2011), to benchmark proteins among different mammalian species (Yang et al, 2013), and to investigate the effects of high SCC on milk proteins (Zhang et al, 2015). Other studies have used proteomics to identify protein biomarkers in bovine milk from cows with mastitis (Hogarth et al, 2004;Pongthaisong et al, 2016), and comparisons have been made between the expression levels of proteins in milk produced by dairy cows with and without mastitis (Hogarth et al, 2004;Li et al, 2014).…”

“…The cathelicidins comprise a family of antimicrobial peptides that contain a conserved N-terminal sequence (the "cathelin" domain) and a C-terminal cationic antimicrobial domain (Zanetti, 2004). In dairy cows, cathelicidin-1, cathelicidin-2, cathelicidin-3, and cathelicidin-4 have previously been found in milk with mastitis after infection with Escherichia coli (Boehmer et al, 2008), and cathelicidin-1 has previously been described as a biomarker for the detection of subclinical mastitis caused by natural Streptococcus agalactiae infection (Pongthaisong et al, 2016). In caprines, Olumee-Shabon et al (2013) identified the presence of cathelicidin-1 and cathelicidin-3 in the milk of induced endotoxin mastitis animals.…”