Effect of Dietary Supplementation of Capsicum Extract on Feed Intake, Milk Production and Composition, Rumen Fermentation, and Rumen Microbial Populations in Dairy Cows

Abstract Text: Dietary supplementation of Capsicum extract (CE) has been reported to increase feed intake and modify ruminal fermentation in cattle. The objective of this experiment was to investigate the effects of CE on feed intake, digestibility, N utilization, milk performance, ruminal fermentation, and ruminal microbial diversity in lactating dairy cows. Eight multiparous Holstein cows (DIM, 50 ± 9.6 d; BW, 591 ± 32.6 kg), including 3 ruminally-cannulated, were used in a replicated 4 × 4 incomplete Latin square design with 25-d periods. Treatments were 0 (CON), 250, 500, and 1,000 mg CE/cow/d. The CE was mixed with a small portion of the TMR and topdressed. Apparent total tract digestibility was not affected by treatment. Treatments also had no effect on urinary-N, urea-N, urinary purine derivatives, and fecal-N excretions. Milk yield tended to quadratically increase (P = 0.08; SEM = 0.86) with CE: 50.5, 51.9, 51.5, and 50.3 kg/d, respectively. Dry matter intake was not affected by CE (27.0 ± 0.64 kg/d). Feed efficiency tended to increase quadratically (P = 0.08; SEM = 0.047) with CE supplementation: 1.90, 1.93, 2.02, and 1.96 kg/kg, respectively. Milk fat yield increased (P = 0.05) for CE treatments compared with CON (1.58 vs. 1.46 kg/d, respectively). Relative to CON, CE increased (P = 0.04) 4% FCM and tended to increase (P = 0.06) energy corrected milk yields. Concentration of milk lactose was decreased (P = 0.01) by CE. Compared with CON, concentration of beta-hydroxybutyrate (BHBA) in blood plasma tended to be higher (P = 0.07) for CE and quadratically responded (P = 0.02) to CE supplementation level. Plasma NEFA was not affected by CE. Ruminal pH tended to be decreased (P = 0.06) by CE compared with CON. Ruminal ammonia and VFA concentrations were not affected by treatment, although acetate tended to linearly decrease (P = 0.11) with CE. Predominant bacteria in rumen contents were Ruminococcaceae spp. and Prevotella spp. (10.8 to 22.6% of the total population). Compared with CON, Prevotella spp., Butyrivibrio spp., and Roseburia spp. were decreased (P ≤ 0.05) by CE. In conclusion, feed intake, total tract digestibility of nutrients, and N utilization were not affected by dietary CE supplementation. However, CE increased milk production, milk fat yield, and plasma BHBA concentration. Collectively, these results suggest that CE may increase lipid mobilization for milk fat synthesis in dairy cows.

Keywords: capsicum extract, feed intake, milk production