Dietary sodium hyaluronate and eggshell membrane improve skin barrier function and coat health in Ragdoll cats

Skin and coat health are important indicators of feline well-being and are influenced by epidermal barrier integrity, nutritional status, oxidative balance, and microbial homeostasis. However, the effects of dietary sodium hyaluronate (SH) and eggshell membrane (ESM), either alone or in combination, remain insufficiently characterized in cats.

Twenty-four healthy 6-month-old Ragdoll cats were randomly assigned to four dietary groups (n = 6 per group): a basal-diet control, 250 mg/kg SH, 250 mg/kg ESM, or 125 mg/kg SH plus 125 mg/kg ESM. After 56 days of supplementation, hair microstructure, coat sensory and colorimetric traits, transepidermal water loss (TEWL), hematological and serum biomarkers, hair nutrient composition, and fecal microbiota were evaluated.

Dietary treatment did not significantly affect body weight. The combined SH + ESM treatment was associated with the most consistent improvements in hair cuticle morphology, hair fiber diameter, coat gloss, compliance, skin elasticity, coat brightness, and TEWL. It was also associated with lower serum malondialdehyde and interleukin-31 concentrations, higher selected antioxidant indices, increased serum zinc, copper, and vitamin E concentrations, and increased deposition of zinc and several amino acids in hair. Alpha diversity of the fecal microbiota was not significantly altered, whereas taxonomic composition differed among treatments, with greater relative abundances of Blautia and Lachnospiraceae-associated taxa in the combined-treatment group.

Combined SH and ESM supplementation was associated with broader skin- and coat-related responses than either ingredient alone. These findings support its potential as a nutritional strategy for maintaining feline skin and coat health; however, the relatively small cohort of healthy juvenile cats and the exploratory nature of the microbiota analyses limit causal and clinical inference.