Dynamic Changes Of Bacterial Community In Uterus Of Postpartum Dairy Cows By Culture And Molecular Method

The uterus infection by bacteria after parturition often causes endometritis. Endometritis delayed the recovery of the uterus, increased intervals from calving to first service or conception, associated with lower conception rates, seriously affected the economic efficiency of dairy production. The objectives of the present study were to determine the bacterial community in uterus from day10to day40after parturition and the relationship between bacteria community and the character of uterus mucus in postpartum dairy cows.1Bacterial community in uterus and the relationship with uterus mucus character of postpartum cowsUterus mucus were collected from42dairy cows from d10to d40after parturition. Bacteria were identified following aerobic and anaerobic culture in vitro. The dominate genus and species bacteria dynamic changes with the postpartum time, and the relationship between mucus character and bacterial community were investigated. The results showed that the most prevalent bacteria in uterine were E. coli (85.7%), Proteus (64.3%) and Staphylococcus sp.(61.9%). The highest isolation rate of bacteria has changed at different postpartum time. The number of bacteria isolated from white or off white mucus and yellow or earthy yellow purulent mucus (5.56±0.38,5.50±1.40) were higher than that isolated from clear mucus (3.48±1.58). Salmonella, Proteus mirabilis, Streptococcus sp. and Arcanobacterium pyogenes were isolated from white or yellow purulent mucus more than clear mucus on d30and d40postpartum. Clostridiales bacterium was associated with yellow or earthy yellow purulent mucus on day40postpartum.2The investigation of the diversity of bacterial community in the uterus of dairy cows after parturitionUterus mucus were collected on day10(H10, M10) and day40(H40, M40) from healthy and endometritis cows after parturition, respectively. Four clone libraries were constructed based on bacterial16S rRNA gene amplified by using universal primers8F/1510R. Total of297positive clones were selected. Sequences belonged to5major groups, Bacteroidetes, Fusobacteria, Firmicutes, Tenericutes and Proteabacteria. The most clone sequences in H10and M10libraries were affiliated with the phylum Bacteroidetes(116), Fusobacteria(14) and Firmicutes(30). The number of36(50.70%) sequences from H10showed high similarity with Bacteroides pyogenes. The ratio of39.24%(31) and13.92%(11) in total sequences from M10library had high identity with Bacteroides heparinolyticus and Peptostreptococcus sp.. Phylogenetic analysis revealed that55.71%and34.29%clones in H40library affiliated Tenericutes and Firmicutes, all the sequences belonged to Tenericutes were related to Ureaplasma diversum. The diversity and abundance of Bacteroidetes from library H40(64,90.14%) significantly decreased than that from library H10(5,7.14%). A total of77positive clones from M40. The ratio of34.29%and33.77%colons belonged to phylum Firmicutes and Proteabacteria,20.78%and33.77%had high identity with Parvimonas sp. and Histophilus somni, respectively.3Shift of bacterial community in uterus of postpartum cows from10days to40days after parturitionMolecular methods of PCR/DGGE and Real-time PCR based on16S rRNA gene were used to study bacterial communities in uterus and changes of bacterial community composition in different character mucus of postpartum cows from d10to d40after parturition. The DGGE profiles of total bacteria community showed that the predominant bands similar to Fusobacterium necrophorum and Bacteroides heparinolyticus only appeared on d30and d40from endometritis cows, the bands similar to Arcanobacterium pyogenes was found only on d40endometritis cows. The similarity index of DGGE profile from20to40days of endometritis cows had high similarity with that d10healthy and endometritis cows. The DGGE profiled from different character uterus mucus reviewed that Fusobacterium necrophorum were associated with brown, yellow or white purulent mucus, Bacteroides heparinolyticus and Prevotella sp. were associated with white or yellow mucus. There is high similarity between the same character mucus. The DGGE profile of Actinobacteria revealed that group Corynebacterium sp. appeared earlier in healthy cows than endometritis, suggested they maybe the beneficial bacteria for uterus. Real-time PCR assay revealed that the total bacteria, Peptostreptococcus spp. and Fusobacterium spp. were all significantly lower in health cows than endometritis cows on d10and d30(P<0.05). Bacteroidetes on20days both health and endometritis cows were significant lower than d10postpartum, while endometritis cows higher than health in10days(P<0.05). The percentages of Peptostreptococcus spp. and Fusobacterium spp. relative to total bacteria were significantly lower in health cows than endometritis cows on d30and d40. A decrease of the number of E.coli were observed both in health and endometrtis cows after30days partutition, while health cows significant higher than endometritis cows on d10and d40(P<0.01).