The objective of this study was to investigate the effects of heat treatment on colostral low-abundant proteins, IgG and IgA, insulin, and insulin-like growth factor I (IGF-I), as well as bacteria and somatic cells. First-milking colostrum samples >8 L and Brix % > 22.0 were harvested from 11 Holstein cows on a commercial dairy in New York State and split into 2 aliquots using single-use colostrum bags. One aliquot of each pair was cooled on ice immediately after harvest (raw, R; n = 11), and the other was heat-treated for 60 min at 60°C (heat, H; n = 11). All samples were analyzed for IgG and IgA via radial immunodiffusion assay and insulin and IGF-I concentrations by radioimmunoassay. Total bacterial counts and somatic cell counts (SCC) were determined using standard plate culture techniques and flow cytometry, respectively. Samples from a subset of 5 pairs (n = 10) were further analyzed by nano liquid chromatography-tandem mass spectroscopy, after ultracentrifugation at 100,000 × g for 60 min at 4°C to enrich the low-abundant protein whey fraction. Data were analyzed using either paired t-test or Wilcoxon signed-rank test or using an online software package to analyze proteomics data. Outcomes of proteomics analysis were fold change ≥1.5 between pairs, and paired t-tests with false discovery rate–adjusted P-value < 0.05. The median reduction of IgA concentrations was 8.5% (range: 0–38.0%) due to heat treatment, whereas IgG concentrations did not change due to treatment. Insulin concentrations decreased by a median of 22% (7–45%), and IGF-I decreased by 10% (0–18%) in H samples. Heat treatment was associated with a median reduction of SCC of 36% (0–90%) in paired samples, as well as a median reduction in total bacterial count of 93% (45–100%) in H versus R samples. Proteomics analysis identified a total of 328 unique proteins that were present in all 10 samples. Nine of the 25 proteins that decreased by at least 1.5-fold in H compared with R were identified as complement proteins. We conclude that heat treatment of colostrum is associated with a reduction in the concentration of bacterial counts and SCC, IgA, insulin, and IGF-I. In addition, proteomics analysis of colostral whey identified several complement components and other proteins that decreased in abundance due to heat treatment. Although IgG concentrations were unaffected and a reduction in bacterial counts was achieved, the change in several immunologically active proteins and growth factors may have biologically important effects on the developing immune system of the neonate fed heat-treated colostrum.
Heat treatment of bovine colostrum : I. Effects on bacterial and somatic cell counts, immunoglobulin, insulin, and IGF-I concentrations, as well as the colostrum proteome / S. Mann, G. Curone, T.L. Chandler, P. Moroni, J. Cha, R. Bhawal, S. Zhang. - In: JOURNAL OF DAIRY SCIENCE. - ISSN 0022-0302. - 103:10(2020 Oct), pp. 9368-9383.
|Titolo:||Heat treatment of bovine colostrum : I. Effects on bacterial and somatic cell counts, immunoglobulin, insulin, and IGF-I concentrations, as well as the colostrum proteome|
|Parole Chiave:||colostrum; heat treatment; immunology; proteome|
|Settore Scientifico Disciplinare:||Settore VET/05 - Malattie Infettive degli Animali Domestici|
|Data di pubblicazione:||ott-2020|
|Data ahead of print / Data di stampa:||20-ago-2020|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.3168/jds.2020-18618|
|Appare nelle tipologie:||01 - Articolo su periodico|
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