0138 Fecal microbial shifts of the German Holstein dairy cows with left-sided displacement of the abomasum

Abstract

One of the most common diseases in high-performance German Holstein dairy cows is left-sided displacement of the abomasum (LDA). Hypomotility of the abomasum is detrimental during the pathogenesis of LDA. Also, it is known that the improper interactions between the gut microbiota and the enteric nervous system contribute to dysfunctions of gastrointestinal motility. Therefore, we hypothesized that the gut microbial composition will be different between German Holstein dairy cows with and without LDA. We compared the fecal microbiota between cows with and without LDA using 16S ribosomal RNA (rRNA) gene analysis. A total of 20 German Holstein dairy cows at one dairy farm in South Korea, including eight cows without LDA (control group) and 12 cows with LDA (LDA Group), were enrolled in this study. All cows were housed under the same conditions and were fed the same feed without any antibiotics or supplementary additives. Right after LDA was diagnosed, fecal samples were collected immediately from the rectum. Total DNA representing the fecal microbial communities was extracted from individual fecal samples using the stool DNA extraction kit, and the 16S universal primers 27F (5′ GAGTTTGATCMTGGCTCAG 3′) and 800R (5′ TACCAGGGTATCTAATCC 3′) were used to amplify 16S rRNA genes (V1-V4 hyper variable regions). The composition and relative abundance of each member of the microbiota in feces from the control group were different from the LDA group. The proportion of Spirochaetes was significantly different between groups at the phylum level (P < 0.001). An average of 1.5% of the microbiota was members of Spirochaetes in the feces of the control group. On the other hand, there were no Spirochaetes detected in the feces of the LDA group. At the genus level, relative abundance of five genera was significantly different between groups. The proportion of the genus Enterohabdus (a member of Actinobacteria), the proportions of members of Firmicutes including Cellulosilyticum, Streptococcus, and Turicibacter, and the proportion of Treponema (a member of Spirochaetes) were all significantly higher in the control group than in the LDA group. However, further studies will be needed to elucidate the roles of these genera in the pathogenesis of LDA. Overall, results from this study show that the fecal microbial compositions of German Holstein dairy cows with LDA shifted and were less diverse than those in normal cows.