Abstract: Background: Enterococcus faecium strain SF68 (SF68) is the bacterium in probiotic and synbiotic products marketed for dogs and cats in many countries. There is published evidence in puppies (improved vaccine responses) and cats (lessened FHV-1 reactivation during stress) that the probiotic may also support immune health.
Hypothesis/Objectives: The purpose of this study was to collect additional information concerning the immune modulatory effects of SF68 when fed as a synbiotic (combined with psyllium as the prebiotic) to healthy research cats.
Methods: Two groups of four young adult research cats were chosen for this IACUC approved protocol. All cats were acclimated to the facility, housed identically, and fed the same diet. The cats were randomized into the synbiotic group or the placebo group (canned food alone). On Day 28, polyA-enriched RNA was extracted from blood leukocytes. RNA sequencing was performed using an Illumina-based platform. Sequence files were aligned with the reference cat genome and assembled using Partek flow software. Gene set expression analysis (GSEA) was performed using open-source software, with significance was set at FDR of < 0.05 and p < 0.1.
Results: Group comparisons of leukocyte transcriptomic data from Day 28 revealed that cats fed SF68 had 45 significantly upregulated genes and 33 significantly downregulated genes. TNF-a and TGF-b signaling pathways were significantly upregulated while interferon-alpha and interferon-gamma pathways were significantly downregulated.
Conclusions/Importance: These findings indicate that feeding SF68 can elicit significant immune responses in circulating leukocytes. Correlative studies of GI responses to this dietary intervention may provide additional insights.
