Antimicrobial activity of brown propolis ethanolic extract and its application in intramammary formulation for the treatment of bovine mastitis.

Abstract

The major sanitary concern in dairy cattle production chain is mastitis, causing uncountable losses, which implies in the need of alternative therapies. Thus, the purpose of this study was to evaluate the antimicrobial activity of brown propolis ethanolic extract and its therapeutic potential for application in bovine intramammary mastitis therapeutic formulation. In the in vitro study we analyzed 40 Staphylococcus sp. isolates from subclinical mastitis cases. The chemical profile of extract was obtained by High Performance Liquid Chromatography. The antimicrobial activity was determined by broth microdilution. The biofilm formation was verified in the microplate adherence assay. To test the in vitro antimicrobial potential of the formulation, 28 bovine mammary glands were used. Mastitis was confirmed by bacterial culture, somatic cells counts (SCC) and California Mastitis Test on seven experimental occasions. In the extract, 28 flavonoids were identified, and this showed antimicrobial activity against all isolates tested in a range between 781 and 1,563 µg ml, concentrations that also interfered with biofilm production. After a seven-day treatment with the formulation, the animals were cured. There was a sharp increase in the SCC, specifically within 24 h and 48 h after the propolis application, with a significant subsequent decrease. The values of lactose, total solids and non-fat solids did not present significant changes. We confirmed the in vitro antimicrobial and antibiofilm activities of extract, as well as its application for bovine mastitis bacteriological cure, without significant changes in milk quality, which represents a natural option to improve the sanity of dairy cattle herds.