Ruminal fermentation and methane production in vitro, milk production, nutrient utilization, blood profile, and immune responses of lactating goats fed polyphenolic and saponin-rich plant extracts

This study was conducted to evaluate the effect of a composite plant extract (CPE) rich in polyphenolics and saponins from seeds of Dolichos biflorus (horse gram), root of Asparagus racemosus (shatavari), bark of Amoora rohituka (rohitaka), and peel of Punica granatum (pomegranate) on ruminal fermentation and methanogenesis in vitro, milk production, nutrient digestibility, immune response, and blood profiles in lactating Beetal goats fed CPE at 20 g/kg diet. Dose effect of CPE was assessed using different doses (0, 10, 20, 30, and 40 g/kg substrate) to find out an optimum dose for the in vivo study. The in vivo experiment lasted 70 days including a 10-day adaptation period. In the in vitro study, dry matter (DM) and fiber degradability increased linearly ( P < 0.05) and methane production and ammonia concentration decreased linearly ( P < 0.05) with increasing doses of CPE. Concentrations of total VFA and proportion of propionate increased ( P < 0.001) linearly, whereas proportion of acetate and acetate to propionate ratio decreased with a linear effect. Dietary CPE increased milk yield ( P = 0.017) and concentrations of protein and lactose ( P = 0.045) by CPE, but concentrations of fat and solid not fat in milk were not affected ( P > 0.10). Somatic cell counts in milk reduced ( P = 0.045) in the CPE-fed goats. Apparent digestibility of DM ( P = 0.037) increased significantly and NDF ( P = 0.066) tended to increase due to supplementation of CPE. Blood glucose ( P = 0.028) and albumin ( P = 0.007) concentrations increased, while other liver-marker metabolites and enzyme activities and superoxide dismutase activity were not altered in goats due to feeding of CPE. Concentrations of total amino acids ( P = 0.010), total essential amino acids ( P = 0.012), and total ketogenic amino acids ( P < 0.001) were greater in the CPE-fed goats than the control goats. Cell-mediated immune response improved due to CPE feeding. This study suggests that the CPE rich in both phenolics and saponins could improve ruminal fermentation, milk production, and nutrient utilization in lactating goats with better health status while decreasing methane emission.