Effects of organic zinc and selenium yeast supplementation on immunological function, antioxidant capacity, skin hydration, and fecal microbiome in dogs

Abstract Background Inorganic trace minerals are commonly used in pet food but are often associated with low bioavailability and environmental concerns. The purpose of this study was to investigate the effects of dietary supplementation with organic zinc (Zn) and selenium (Se) on immune response, antioxidant status, selected skin and hair parameters as well as gut microbiome in adult dogs. A total of 18 adult Poodles, aged 1 ~ 7 years, were randomly assigned to three dietary treatment groups: (1) the inorganic trace mineral (ITM) group: dogs fed a basal diet containing inorganic trace minerals; (2) the organic Zn (OZ) group: dogs fed a basal diet supplemented with organic Zn; (3) the organic Zn and Se (OZS) group: dogs fed a basal diet supplemented with organic Zn and Se yeast. The feeding trial lasted 28 days. Results On day 28, serum glutathione peroxidase activity was higher in the OZS group compared to the ITM group ( P < 0.05). Serum tumor necrosis factor-α levels were lower in the OZS group compared to the ITM group on days 14 and 28 ( P < 0.05). On day 28, serum diamine oxidase activity was lower in the OZS group than in the ITM and OZ groups ( P < 0.05). Skin water content was higher in both the OZ and OZS groups compared to the ITM group ( P < 0.05). The relative abundances of Escherichia , Klebsiella and Shigella were higher in the ITM group, whereas Enterococcus , Lactobacillus and Ligilactobacillus were enriched in the OZ and OZS groups ( P < 0.05). Furthermore, the fecal butyrate concentration was higher in the OZS group compared to the ITM and OZ groups ( P < 0.05). Conclusion In this 28-day feeding trial, supplementation with organic Zn and Se yeast was associated with differences in selected inflammatory parameters, antioxidant status, skin water content and fecal butyrate concentration, as well as differences in fecal microbiome composition in adult dogs. These findings provide preliminary evidence for the potential effects of organic trace mineral supplementation on physiological and microbiome-related parameters in dogs.