Year: 2004
Type: dissertation
Abstract: The non-specific, multifunctional glycoprotein lactoferrin (Lf) is present in milk and external body secretions.It is released by the secondary granules of neutrophils and epithelial cells in high concentrations in response to inflammatory stimuli.Lf has a broad-spectrum antimicrobial activity, especially against coliform bacteria, such as Escherichia coli, which cause severe mastitis in dairy cows.Since treatment of severe coliform mastitis using antimicrobial agents is problematic, Lf as a natural protein may offer an alternative for treating this disease.The aim of this work was to evaluate the usefulness of exogenic Lf in mastitis treatment.First, normal concentrations of Lf and citrate in the early dry cow secretion of healthy cows were studied.Second, the antimicrobial efficacy of Lf against udder pathogens, particularly E. coli, was tested in vitro.Third, the disposition kinetics of Lf infused into the udder quarters of dairy cows was investigated.Finally, the antibacterial effect of Lf was studied in an experimental E. coli mastitis model.To determine the normal concentrations of Lf and citrate, milk and dry udder secretion samples were collected on the last day of lactation before the drying-off, and then 2 and 6 days later.The mean Lf concentration in the milk increased from 5.29 mg/ml on the last day of drying-off to 8.09 and 11.26 mg/ml 2 and 6 days later, respectively.Citrate concentration decreased from 1.85 mg/ml to 1.54 and 1.09 mg/ml, respectively.Concentrations varied greatly between cows and even between udder quarters at each time-point.Median molar ratio (citrate to native Lf) decreased gradually from 153 on the last day of lactation to 44 on day 6 after drying-off.The antibacterial effect of Lf was tested in vitro against E. coli, Staphylococcus aureus, and coagulase-negative staphylococci (CNS) as well as on Pseudomonas aeruginosa and Klebsiella pneumoniae, originally isolated from bovine mastitis.Concentrations of Lf used were 0.67, 1.67 and 2.67 mg/ml.The best inhibitory activity of Lf was seen against E. coli and P. aeruginosa.The inhibitory effect of Lf for E. coli was concentration-dependent, and variation between the five isolates of E. coli was small.None of the isolates was totally resistant to Lf.The growth of two isolates of P. aeruginosa was clearly inhibited in Iso-Sensitest Broth, in contrast to two K. pneumoniae isolates, which were virtually unaffected.
Source: Työväentutkimus Vuosikirja
Author: T. Kutila
Language: English
Subfield: Animal Science and Zoology
Domain: Life Sciences
Open Access status: green
Funders: Helsingin Yliopisto, Tekes, Vetcare
OpenAlex ID: W2152863903