Supplementation of tropical red seaweeds improved gut health indices, antioxidant status and immunity in adult dogs

We explored the effect of supplementation of two tropical red seaweeds, Kappaphycus alvarezii (KA) and Gracilaria salicornia (GS) at three different levels (0, 1.5 and 3%) on nutrient utilization, gut health, antioxidant, and immune status in adult dogs. The experiment was based on a 5 x 5 Latin square design (LSD) comprising five adult Labrador dogs, five dietary treatments (CON: basal diet; KA_L: KA at 1.5 % of diet dry matter (DM); KA_H: KA at 3 % DM; GS_L: GS at 1.5 % DM; GS_H: GS at 3 % DM) and five periods, each of 21 days, followed by a 7-day washout period in between. The palatability, food intake, and body weight changes were comparable among the groups (P>0.05). The supplementation of two seaweeds at either level did not have any effect on nutrient digestibility (P>0.05). The fecal lactate concentration was higher (P<0.05) in GS_L and GS_H groups whereas fecal ammonia was lower (P<0.05) in the GS_H group in comparison to the other groups. The volatile fatty acids (VFA) profile improved (P<0.05) in the KA_H, GS_L, and GS_H groups. The mean fecal Lactobacillus count tended to increase (P<0.10) in the KA_H and GS_H groups while the coliform count remained unaffected by seaweed supplementation. The mean fecal Bifidobacterium population was higher (P<0.05) and the mean clostridial population was lower (P<0.05) in the GS_H group as compared to -other groups. The concentration of reduced glutathione (GSH) was higher (P<0.05) and lipid peroxides were lower in the KA_H and GS_H groups. A tendency (P<0.10) of improved cell-mediated immunity (CMI) was observed in the GS_H group as compared to other groups. Overall, the supplementation of either of the seaweeds at 1.5 % failed to exert significant influence on any of the parameters studied except fecal VFA and lactate levels, whereas both the seaweeds at 3% level showed some promising benefits in terms of improved gut health, antioxidant, and immune status and the best response was obtained in GS_H group. Hence, it can be concluded that supplementation of GS at the 3 % level outperformed KA supplementation at the 3 % level by improving gut health, antioxidant status and immunity.