The Use of Ascophyllum nodosum and Bacillus subtilis C-3102 in the Management of Canine Chronic Inflammatory Enteropathy: A Pilot Study

SIMPLE SUMMARY: The development of novel, safe and effective therapies is highly desired for managing diseases requiring long-term use of drugs endowed with side effects. In the present investigation, we aimed to assess the impact of gut microbiota modulation strategies, i.e., the brown seaweed Ascophyllum nodosum and/or the probiotic microorganism Bacillus subtilis C-3102, in dogs diagnosed with Canine Chronic Inflammatory Enteropathy. The tested agents were administered on top of a hydrolysed protein diet, in a step-up fashion at 30-day intervals, with faecal collection and clinical evaluation of disease severity being performed before study initiation as well as at the end of each treatment phase. Neither Ascophyllum nodosum, nor its association with Bacillus subtilis C-3102, were able to significantly alleviate clinical signs and augment bacterial richness within the study population. Notwithstanding, increased numbers of beneficial carbohydrate-fermenting bacteria, alongside with higher amounts of faecal acetate were recorded, suggesting a potentially positive effect on gut health. ABSTRACT: The aim was to assess the effects of Ascophyllum nodosum (AN) with/without Bacillus subtilis C-3102 as alternative treatments for Chronic Inflammatory Enteropathy (CIE) of dogs. Fourteen CIE patients, which had received the same control (CTR) diet, were enrolled to serially receive three diets: (1) hydrolysed protein (HP) diet; (2) 4.0% AN supplemented HP (HPA) food, (3) HPA diet fortified with 125 billion B. subtilis C-3102 spores/10 kg body weight (HPAB diet). Clinical outcome was assessed by Canine Inflammatory Bowel Disease Activity Index (CIBDAI), whereas gut microbiota compositional variations were investigated via 16S rRNA gene analysis, and faecal fermentation end-products by liquid chromatography. Higher abundances of the Ruminococcaceae and Rikenellaceae families were shown in HPA relative to CTR treatment, with Bacillus genus being differentially abundant on HPAB diet. Concentrations of acetate were higher (p < 0.05) in dogs fed HPA compared to CTR diet, and amounts of isovalerate and isobutyrate were greater (p < 0.05) in HPA compared to HP food. A tendency for higher amounts of faecal butyrate was found for the HPAB treatment (p = 0.06). Comprehensively, while displaying potentially positive effects on faecal fermentations, the tested substances failed to improve CIBDAI scores and microbial richness in CIE dogs.