Effects of Capsicum Oleoresin on Feed Intake, Milk Production, Immune Responses, Blood Metabolites, and Hormones in Lactating Dairy Cows

摘要

In both dairy and beef production systems, there has been interest in using plant extracts to enhance productivity and feed efficiency. Capsicum oleoresin (CO), an ethanolic extract from the fruit of Capsicum plants, has been reported to modify rumen fermentation in ruminants. This is attributed to an antibacterial effect of capsaicinoids, the active compounds of Capsicum. In addition, capsaicinoids reportedly alter host responses in rats and humans. Studies have also shown that capsaicinoids had immunoregulatory effects, stimulate digestive enzymes, regulated appetite-related hormones, and alter blood metabolites. In a series of experiments, the effects of CO were investigated on the host responses as well as rumen fermentation in lactating dairy cows.;The objective of the first experiment was to investigate the effect of CO supplied postruminally on nutrient utilization, gut microbial ecology, immune response, and productivity of lactating dairy cows. Treatments were control (no CO) and daily doses of 2 g/cow of either CO for 9d. Milk yield was decreased by CO treatment compared with the control. The treatments did not affect nutrient utilization and gut microbial ecology. The relative proportion of lymphocytes was increased by the CO treatment compared with the control. The CO treatment increased the proportion of total CD4+ cells and total CD4+ cells that co-expressed the activation status signal CD25 in blood. Collectively, the CO used in the first trial appeared to have an immune-stimulatory effect by activating and inducing the expansion of CD4 cells in dairy cows. Although CO treatment decreased milk yield, this should be interpreted with caution because of the short duration of treatment. The objective of the second experiment was to investigate the effect of Capsicum oleoresin in granular form (CAP) on feed intake, immune responses, oxidative stress markers, rumen fermentation, and productivity of lactating dairy cows. Treatments included control (no CAP) and daily supplementation of 250, 500, or 1,000 mg CAP/cow. Dry matter intake was not affected by CAP, but milk yield tended to quadratically increase with CAP supplementation. The CAP treatments quadratically increased energy-corrected milk yield. The CAP treatment did not affect oxidative stress markers, rumen fermentation. Blood serum beta-hydroxybutyrate was quadratically increased by CAP, whereas the concentration of nonesterified fatty acids was similar among treatments. Mean fluorescence intensity for phagocytic activity of neutrophils tended to be quadratically increased by CAP. Numbers of neutrophils and eosinophils and the ratio of neutrophils to lymphocytes in peripheral blood linearly increased with increasing CAP. Overall, in the conditions of the trial, energy-corrected milk yield was quadratically increased by CAP, possibly as a result of enhanced mobilization of body fat reserves with CAP supplementation. In addition, CAP increased neutrophil activity and immune cells related to acute phase immune response. The objective of the third experiment was to investigate the effects of rumen-protected Capsicum oleoresin (RPC) supplementation on feed intake, digestibility, milk production, and responses to an intravenous glucose challenge and an immune challenge in lactating dairy cows. Treatments were 0 (control), 100, and 200 mg RPC/cow/d. Dry matter intake and milk yield tended to quadratically increase with RPC. Feed efficiency linearly increased with RPC supplementation. Apparent total tract digestibility of DM, OM, and CP and fecal N proportions of N intake were linearly increased by RPC supplementation. During a glucose tolerace test, serum insulin was decreased by RPC while glucose concentration in serum was not affected. After an immune challenge, cortisol and haptoglobin concentration in serum were lower in RPC treatment than the control. In conclusion, Capsicum may stimulate productivity and insulin activity and alleviate acute phase responses in lactating dairy cows.