Dietary tropical seaweed supplementation modulates antioxidant status and immune response in adult Labrador Dogs

<title>Abstract</title> <p> The present study evaluated the effects of dietary supplementation with the tropical seaweeds <italic>Gracilaria salicornia</italic> and <italic>Turbinaria conoides</italic> on blood biochemical parameters, antioxidant status, and immune responses in adult Labrador dogs, using <italic>Cichorium intybus</italic> (chicory) as a reference functional feed ingredient. A 4 × 4 Latin square design was employed using four adult Labrador Retriever dogs (~ 7 years; BW 16.48 ± 2.63 kg), four dietary treatments, and four experimental periods of 21 days. Dogs in the control group (CON) received a basal diet(NRC 2006), while groups CH, TC, and GS were supplemented with chicory, <italic>T. conoides</italic> , and <italic>G. salicornia</italic> , respectively, at 3% dietary dry matter. Hematological and serum biochemical parameters remained within normal physiological ranges and were not significantly affected by dietary treatments (P &gt; 0.05). Serum T3 and T4 concentrations were comparable among treatments, whereas serum cortisol concentrations were significantly lower (P &lt; 0.05) in the GS and TC groups than in the control. Catalase and superoxide dismutase activities were unaffected (P &gt; 0.05); however, supplementation with <italic>G. salicornia</italic> and <italic>T. conoides</italic> significantly increased (P &lt; 0.05) glutathione, glutathione peroxidase, ferric reducing antioxidant power,serum IgG, serum IgA, and cell-mediated immune response, while significantly reducing malondialdehyde concentrations. Among the treatments, <italic>G. salicornia</italic> produced the most consistent improvements in antioxidant and immune indices, indicating its potential as a functional dietary ingredient for adult dogs. </p>