Effect of rearing system on carcass traits and meat quality of rabbits

We have developed a working protocol in order to evaluate the air contamination in different kinds of rabbitries for breeding rabbit used for experimental procedures using an easy instrument for sampling, the SAS® System (PBI International, Italy) and plates filled with different types of cultural media. [1‐2] The two trials have been performed in a rabbit farm located in the NW of Italy. White New Zealand rabbits (NZR) were housed in two different rooms of the same building, with forced ventilation, one for does and one for fatteners. For air sampling we have used the SAS® System that is an impaction method that allows to enumerate the number of microorganisms directly in elevated convex plates filled with cultural media. A known volume of air is thrown onto a Surfair plate; then the sample is incubated depending on the microorganisms we want to isolate. The results are expressed as CFU (Colony Forming Unit)/m3. During the first trial developed in the rabbit farm, the bacterial charge we have observed was always above 50 CFU/m3 of aspired air; Micrococcus luteus and Staphylococcus spp. were the most isolated microorganisms in both kind of samples. For fungi, 100% of plates were positive for environmental fungi and yeasts such as Aspergillus spp., Penicillium spp., Alternaria spp. and Rhodotorula rubra but their number remained under 50 CFU/m3. The percentage of dermatophytes isolated was between 50 and 70 and the only species identified was Trichophyton mentagrophytes as in opened plates. [3] During the second trial, the microbiological results showed a total bacterial charge between 50 and 100 CFU/m3 air flow, using the SAS® System. On the contrary, the total fungal charge (environmental fungi and dermathophytes), keeps below 50 CFU/m3. These values could be considered low (50‐100 CFU/m3) and very low (<50 CFU/m3) with regards to the environmental risk according to the parameters supplied by the SAS System’s producer. The isolated microorganisms were Bacillus (100%), Alternaria (11,09%), Aspergillus niger (36,12%) and Microsporum gypseum (41,67%). None of the bacteria/fungi that we have isolated was strictly pathogens. So, the method we have applied for the evaluation of the microbial air quality allows us to obtain good and reproducible qualitative and quantitative results while opened plates allow only a qualitative results. Moreover, the SAS® System is portable and noiseless and it is optimal for sampling air in the nests and in cages or in a facility room. 1. Martino PA, Jacchia G, Cocilovo A. Prevalenza delle dermatofitosi in conigli con lesioni cutanee, utilizzati per fini scientifici. Atti LII Conv. Naz. SISVet 1998;159‐160 2. Martino PA, Luzi F, Verga M. Microbiological control of the environment in an intensive rabbit rearing. Proc. of the 8. World Rabbit Congr., WRSA, 576‐581 (2005). 3. Mehta SK, Mishra SK, Pierson DL. Evaluation of three portable sampler for monitoring airborne fungi. Appl. And Environm. Micr. 1835‐1838 (1996).