Beneficial effects of dietary supplementation of tropical seaweeds on rumen fermentation, antioxidant status, immunity and milk yield of lactating Murrah buffaloes

This experiment was carried out to evaluate the effect of dietary supplementation of three different tropical seaweed species on rumen fermentation, methane emission, antioxidant status, immunity and milk production in lactating Murrah buffaloes. Twenty-four lactating Murrah buffaloes were divided into four groups of six each in an experiment based on randomized block design (RBD) and were fed to meet their nutrient requirements (ICAR 2013). Animals in control (CON) group were fed basal diet without any supplemental seaweed, however, Kappaphycus alvarezii (KA), Gracilaria salicornia (GS) and Turbinaria conoides (TC) were supplemented at 1% of the dietary dry matter in KA, GS and TC groups, respectively. Intake and apparent digestibility of nutrients, plasma concentrations of selected blood metabolites, and thyroid hormones were similar among the groups. Supplementation of KA and GS, but not TC increased (P < 0.001) the proportion of propionate in rumen fluid with a concurrent decrease (P < 0.001) in acetate: propionate. The enteric methane emission was lower (P < 0.05) in KA, GS groups and the maximum values were observed in groups CON and TC. Total antioxidant capacity (TAC) and immune response (cell-mediated and humoral) were higher (P < 0.001), and MDA was lower (P < 0.001) in seaweed-fed groups as compared to CON; the higher response was observed in group KA, followed by TC and GS. Plasma concentration of cortisol was lower (P < 0.001) in group KA as compared to other groups. Milk yield and the 6% fat-corrected milk (FCM) yield (kg day⁻¹) were higher (P = 0.009) in KA, followed GS, corresponding values in group TC were not significantly different than those of group CON. Thus, supplementation of the tropical red seaweed improved antioxidant status, cellular and humoral immunity, and milk yield; the greater response was obtained when KA was used as feed supplement. It is concluded that supplementation of K. alvarezii at 1% of dietary DM of lactating Murrah buffaloes would improve antioxidant status, immunity and milk yield with reduction in enteric methane emission.