Oligomeric ultranano hydrogen water improves flock uniformity, antioxidant capacity and intestinal health in growth phase layer-type chickens

This study evaluated the effects of oligomeric ultranano hydrogen water (OUHW) supplementation on growth performance, immune function, intestinal development, gut microbiota, and metabolic profiles in growing layer-type chickens. A total of 96 healthy chicks were randomly assigned to two treatments (six replicates per treatment, eight birds per replicate): a control group (CON) receiving standard drinking water and an OUHW group, with a 12-week experimental period. OUHW supplementation did not significantly affect average daily feed intake (ADFI), average daily gain (ADG), or feed-to-gain ratio (F/G) (P > 0.05); however, flock uniformity was significantly improved (P < 0.05). No significant differences were observed between treatments in immune organ indices, including the thymus, spleen, and bursa of Fabricius (P > 0.05). Antioxidant capacity was enhanced in the OUHW group, as evidenced by significantly increased serum activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) (P < 0.05), whereas total antioxidant capacity (T-AOC) and malondialdehyde (MDA) levels were not affected (P > 0.05). Furthermore, OUHW supplementation did not significantly alter serum concentrations of immunoglobulin A (IgA), IgG, or IgM, nor jejunal levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-2, IL-4, or secretory IgA (P > 0.05). In contrast, ileal villus height (VH) and the villus height-to-crypt depth ratio (VH/CD) were significantly increased in the OUHW group (P < 0.05), indicating improved intestinal development. Cecal microbiota analysis revealed greater microbial richness and diversity in OUHW-treated birds, accompanied by significant shifts in community composition, including enrichment of Firmicutes and Ruminiclostridium (P < 0.05). Metabolomic analysis identified 356 differential metabolites, with enriched pathways related to autophagy, riboflavin metabolism, and vitamin digestion and absorption.