The Research On Airborne Fungi And Its Diversity In Sheep Houses

The airborne fungi in livestock farms poses a great threat to animal husbandry,because it is able to cause many diseases,like mycosis,allergy and mycotoxicosis.What's more,long-time exposure to fungus aerosol would make immune system suppressed and animals are more likely to be infected.In recent years,the type of sheep breeding has changed dramatically,transforming from free-ranging to intensive raising.Due to the increasing closed sheep houses and stocking density,the animal breeding environment situation seems to get worse and increases risk factors to animal health.In this study,the air quality of sheep farms in Shanxi province were investigated in 2016 from April to December.An Andersen six-stage microbial sampler were used to collect the air and RBM served as the sampling medium,which collected the air of four seasons in 2016 and three periods during the day.The research determined and analyzed the concentration,microflora,distribution characteristics of airborne fungi,and how other factors affected it.Subsequently,the diversity and similarity between the fungal community in air and matrix(forage,soil and manure)in sheep houses were analyzed by ERIC-PCR fingerprinting.Therefore,this study could provide a basis for how to reduce microbial contamination in sheep houses.The results showed that:(1)The concentration of airborne fungi in sheep houses ranged from 516(±67)to 3891(± 1335)cfu/m3 of the year,which was highest in autumn and it was significantly higher than other seasons(P<0.05).In spring and autumn,the concentration was highest at 1 p.m.and lowest at 9 a.m.during the day.In summer,the concentration of airborne fungi gradually decreased from 9 a.m.to 5 p.m.,while in winter,it showed the opposite trend.The temperature and relative humidity had great influence on the concentration in autumn,which was positively associated with the temperature and showed a negative correlation with relative relative humidity.(2)The fungal particles were mainly distributed at stage 3 to 5 of the sampler,stage 4 had the highest proportion accounted for 31%-44%,while there were few particles at stage 6.The CMD of these particles ranged from 1.3?m to 2.9?m,and about 80%to 87%of total fungal particles were more likely to enter alveolar with diameters less than 5?m.The maximum concentration of these particles was 3102cfu/m3.(3)Total 560 fungal isolates were purified and 17 genera were identified.The dominant fungi genera in sheep houses were Penicillium,Aspergillus,Alternaria and Mycelia Sterilia,The Aspergillus spp.and Mycelia Sterilia had the highest amount in summer.In other seasons,the concentration of Penicillium spp.was the highest,followed by Aspergillus spp.or Mycelia Sterilia.(4)The variance range of genetic similarity coefficient between fungi community in air and matrix(forage,soil and manure)Was 0.53-0.70.There was large difference among airborne fungi community in different sheep houses and the similarity coefficient ranged from 0.46 to 0.51.Based on the results,it suggested that the fungi escaped from forage,soil and manure could be formed into fungus aerosol inside the sheep houses.