Spent coffee grounds alter bacterial communities in latxa dairy ewes

Abstract: Antimicrobial and antioxidant properties of spent coee grounds (SCG) make them a
potential ingredient in a diet for ruminants. This study investigated the eects of SCG on rumen
microbiota. For 51 days, 36 dairy ewes were assigned to the experimental treatments (0, 30, 50,
and 100 g SCG/kg). Ruminal samples were collected on day 50. DNA was extracted and subjected
to paired-end Illumina sequencing of the V3-V4 hypervariable region of the 16S rRNA genes.
Bioinformatic analyses were performed using QIIME (v.1.9.0). SCG increased dose-dependently
bacterial diversity and altered bacterial structure. Further, 60, 78, and 449 operational taxonomic
unit (OUT) were dierent between control and 30, 50 and 100 g/kg SCG groups, respectively.
Higher dierences were observed between the control and 100 g/kg SCG group, where OTU of the
genera Treponema, CF231, Butyrivibrio, BF331, Anaeroplasma, Blautia, Fibrobacter, and Clostridium were
enriched with SCG. Correlations between volatile fatty acids (VFA) and bacterial taxa were sparser
in the SCG groups and had little overlap. Certain bacterial taxa presented dierent signs of the
correlation with VFA in SCG and control groups, but Butyrivibrio and Blautia consistently correlated
with branched-chain VFA in all groups. SCG induced shifts in the ruminal bacterial community and
altered the correlation networks among bacterial taxa and ruminal VFA.