Fig. 11
Sialidase inhibitor alleviates SRMT-induced mastitis and systemic inflammatory responses in mice. A The ruminal sialidase levels from indicated groups (n = 6). B. PCoA showed distinct ruminal microbial structure (R = 0.1833, P = 0.009) between health and SARA groups based on unweighted UniFrac distance (n = 6). C Microbial compositions at the phylum level from indicated groups (n = 6). D LEfSe analysis identified the different taxa in different treated groups (log10LDA score > 3) (n = 6). E RMT experimental protocol. Mice were treated with antibiotics (200 mg/kg ampicillin, metronidazole and neomycin and 100 mg/kg vancomycin) daily through oral gavage for 5 days. Furthermore, mice were orally gavaged with 300 μL of ruminal supernatant for three consecutive days after antibiotics removal and once every 2 days thereafter for 19 days. The control mice were orally gavaged with an equal volume of sterile PBS. SRMT + Z group was treated with zanamivir (0.5 mg/mL in drinking water) simultaneously for 21 days (n = 7). F PCoA showed successful ruminal microbial colonization after RMT based on unweighted UniFrac distance (R = 0.6720, P = 0.001, n = 7). G PCoA showed distinct ruminal microbial structure between different RMT groups based on unweighted UniFrac distance (R = 0.6085, P = 0.001, n = 7). H Microbial compositions at the phylum level in different treated groups (n = 7). I. LEfSe analysis identified the different taxa in different RMT groups (log10LDA score > 3.5) (n = 7). J, K The intestinal sialidase and Neu5Ac levels from different treated groups (n = 7). L Representative H&E-stained sections of mammary glands from the indicated mice (scale bar, 50 μm). M Histological scores of mammary tissues from the different treatment groups (n = 7). Inflammatory markers of mammary TNF-α (N), IL-1β (O) and MPO activity (P), and fecal lipocalin-2 (Q) and serum LPS (R), and were assessed by ELISA (n = 7). Data are expressed as boxplot (A) or the mean ± SD (J–K and M–R). A Student’s t test (A) or one-way ANOVA was performed, followed by Tukey test (J–K and M–R). *p < 0.05, **p < 0.01, ***p < 0.001 indicate significance. Z, zanamivir