Seaweed Supplementation Failed to Affect Fecal Microbiota and Metabolome as Well as Fecal IgA and Apparent Nutrient Digestibility in Adult Dogs

SIMPLE SUMMARY: Seaweeds represent a source of bioactive compounds that have recently drawn the attention of the scientific community for their possible application as health-promoting ingredients. In particular, their indigestible polysaccharides have exhibited promising prebiotic properties both in humans and in farm animals. The present study investigated for the first time in healthy adult dogs the effects of dietary supplementations with intact seaweeds (brown algae Ascophyllum nodosum, Undaria pinnatifida, Saccharina japonica and red alga Palmaria palmata) on some fecal bacterial populations and metabolites, fecal IgA and apparent total tract digestibility of nutrients. The different algal supplementations (fed to ten healthy adult dogs at a dietary dose of 15 g/kg for 28 days) did not have any significant effect on the selected fecal microbial parameters, intestinal immunity and nutrient digestibility. Further studies investigating higher dietary inclusions of intact seaweeds or their polysaccharide extracts are needed to gain a better understanding of the potential of these interesting marine resources in companion animal nutrition. ABSTRACT: The present study investigated in dogs the dietary effects of intact seaweeds on some fecal bacterial populations and metabolites, fecal IgA and apparent total tract digestibility (ATTD). Ten healthy adult dogs were enrolled in a 5 × 5 replicated Latin square design to evaluate five dietary treatments: control diet (CD); CD + Ascophyllum nodosum; CD + Undaria pinnatifida; CD + Saccharina japonica; CD + Palmaria palmata (n replicates per treatment = 10). Seaweeds were added to food at a daily dose of 15 g/kg. The CD contained silica as a digestion marker. Each feeding period lasted 28 d, with a 7 d wash-out in between. Feces were collected at days 21 and 28 of each period for chemical and microbiological analyses. Fecal samples were collected during the last five days of each period for ATTD assessment. Dogs showed good health conditions throughout the study. The fecal chemical parameters, fecal IgA and nutrient ATTD were not influenced by algal supplementation. Similarly, microbiological analyses did not reveal any effect by seaweed ingestion. In conclusion, algal supplementation at a dose of 15 g/kg of diet failed to exert noticeable effects on the canine fecal parameters evaluated in the present study.