Rumen cannulation is a surgical technique used to collect rumen contents from
ruminants. However, rumen cannulation surgery may potentially impact the
composition of the rumen microbiota. This study aimed to examine the
longitudinal alterations in the rumen microbiota composition of Hanwoo steers
after cannulation surgery. In this study, eight Hanwoo steers were used; four
steers underwent rumen cannulation surgery (cannulation group), while the
remaining four were left intact (control group). Rumen samples were collected
from all eight steers using the stomach tubing method on the day before surgery
(day 0) and on postoperative days 1, 4, 7, 10, 14, 17, 21, 24, and 28, resulting
in 80 samples (10 timepoints × 8 animals). The microbiota of all 80
samples were analyzed using 16S rRNA gene amplicon sequencing with Quantitative
Insights into Microbial Ecology version 2 (QIIME2). There were no significant
differences (
p
> 0.05) in all major phyla and most major
genera representing at least 0.5% of total sequences across all 80 samples
between the control and cannulation groups on the preoperative and postoperative
days. However, while the alpha diversity indices did not differ
(
p
> 0.05) between the two groups on the
preoperative day, they significantly differed (
p
< 0.05)
between the two groups on the postoperative days. Further, the overall microbial
distribution based on both unweighted and weighted principal coordinate analysis
plots significantly differed (
p
< 0.05) between the two
groups on both the preoperative and postoperative days. Orthogonal polynomial
contrasts indicated that major genera and microbial diversity in the cannulation
group decreased following surgery but returned to their initial states by
postoperative day 28. In conclusion, this study demonstrates that rumen
cannulation surgery affects some major taxa and microbial diversity, suggesting
that the rumen cannulation method can alter the composition of rumen microbiota
in Hanwoo steers.