A method to evaluate the microbial air composition in rabbit farm

The microbiological monitoring of air and surfaces has the purpose to evaluate the hygienic conditions of environment to be sure that the disinfecting operations are correctly performed or to decide what kind of operation would be better to assure a good environmental quality. Since environmental quality, particularly of air, is tightly correlated with animal welfare, it is very important to find methods for the evaluation of the air in animal farms. The last EU directives and EFSA opinions are quite restrictive in relation to the management and housing systems. An important topic is represented by the air pollution in relation to the microbial charge; above all it is interesting to evaluate the presence of bacteria, fungi and dermatophytes (zoonotic agents) that quickly spread from animal to animal and to human workers. In fact rabbits are particularly sensitive to environmental conditions and to stress due to changes in some parameters (e.g., temperature, relative humidity, NH3 concentration, etc.) that can increase their susceptibility to potential pathogens. In our experience, we have used an easy method and a working protocol in order to check and control the air contamination in an intensive rabbit farm, located in Lombardia region, analyzing the air samples inside the shed and inside the cages and nests during a period of three years (2004-2007). This method is based upon the SAS® System (PBI International, Italy), an impaction method by which the air is collected directly on the Petri plates filled with the chosen cultural medium. In our protocol we have decided to evaluate the total microbial charge and the fungal one. So we used as cultural media Tryptic Soy Agar (Oxoid, Italy) for bacterial growth, Sabouraud Dextrose Agar (Oxoid, Italy) for environmental fungi (such as Aspergillus spp., Penicillium spp., Alternaria, spp.) and Dermasel Agar (Oxoid, Italy) for dermatophytes (Microsporum and Trichophyton). After many trials we have observed that this method, compared with the “opened plates” method, allows to obtain repeatable results in a brief time and to perform the tests with low cost. The results allow to evaluate the environmental status of rabbitries, to know the welfare of reared rabbits and to decide the hygienic operation to perform in the breeding farms.