Estudio de la Actividad Antimicrobiana de Nano Plata sobre Mastitis Subclínica Bovina en la Unidad Productiva Tunshi

Abstract

The increase of bovine subclinical mastitis and microbial resistance to conventional antibiotics causes losses to the dairy sector and gives rise to the search for new antimicrobials, that is why the antimicrobial activity of nano silver on this disease was determined. The study was carried out in the dairy herds of the Tunshi Production Unit of the Faculty of Livestock Sciences, Escuela Superior Politécnica de Chimborazo. The experimental method was applied to milk samples from 38 cows, determining the degree of mastitis by CMT test. It was observed that 68.4 % presented subclinical mastitis, 5.3 % clinical mastitis and 26.3 % presented negative reaction to the test. In the samples that presented subclinical mastitis, the microorganisms that caused the mastitis were isolated and identified and then in vitro and in vivo tests were carried out by adding nano silver suspension at concentrations of 0.88, 1.75, 3.5 and 7 ppm. The microorganisms isolated and identified were Staphylococcus epidermidis 45 %, Staphylococcus aureus 32 %, Escherichia coli 16 % and Bacillus sp. 8 %. In the "in vitro" analysis with the nano silver suspension at a concentration of 7 ppm, a large number of microorganisms were inhibited as follows: Staphylococcus aureus 92.1 % in 60 minutes, while: Staphylococcus epidermidis 98.9%, Escherichia coli in 99.4% and Bacillus sp in 99.3 % in 30 minutes. While in the "in vivo" analysis with the same concentration of nano silver (7 ppm) a 7.7 % effectiveness was achieved. In conclusion, the antimicrobial activity "in vitro" presented an effectiveness of 97.43% with which only 7.7% of the bovine subclinical mastitis was controlled, so it is recommended to carry out new investigations with higher concentrations of this suspension.