Effect of Supplementation of Evening Primrose Extract on Growth Performance, Nutrient Digestibility, Blood Characteristics, Fecal Microbiota and Fecal Score in Weanling Pigs

Abstract Text: Evening primrose is a biennial herb that has a long history as an alternative medicine. It has been reported to be used in the treatment of disease in human because of the high content of polyphenol and abundant γ-linolenic acid. A 6-week experiment using 100 commercial cross-bred pigs [(Duroc × Yorkshire) × Landrace, weanling at d 21] with body weight of 6.21 ± 0.62 kg was conducted to evaluate the effect of evening primrose extract (EPE) on growth performance, nutrient digestibility, blood characteristics, fecal microbiota and fecal score in pigs. Pigs were randomly assigned to 1 of 5 treatments according to their sex and body weight. There were 4 replicate pens with 5 pigs per pen (3 barrows and 2 gilts). The pen was considered as the experimental unit in the statistical model. Dietary treatment included: 1) NC, basal diet; 2) PC, NC+ 0.1% antibiotics (33ppm Tiamulin); 3) EPE1, NC + 0.05% EPE; 4) EPE2, NC + 0.1% EPE; 5) EPE3, NC + 0.2% EPE. The average daily gain (ADG) was enhanced in EP1 in the phase 2 (560 vs. 517 g, P<0.05) and overall period (485 vs. 454 g, P<0.05) compared with the NC treatment. The group PC and EPE1 had greater gain/feed (G/F) in the phase 2 (0.73, 0.76 vs. 0.68, P<0.05) and the whole experiment time (0.74, 0.75 vs. 0.70, P<0.05) compared with NC treatment. At the 6 week, the coefficiency of total tract apparent digestibility (CTTAD) of dry matter (DM) was enhanced (82.3 vs. 79.9%, P<0.05) by the supplementation of 0.05% EPE compared with the NC treatment. Compared with the NC, dietary EPE1 and EPE2 decreased (43.4 vs. 34.4, 33.0 mg/dL, P<0.05) the low density lipoprotein-cholesterol (LDL-cholesterol) concentration at the 6^th week. The adding of antibiotic and 0.1% EPE increased (P<0.05) the population of fecal Lactobacillus and decreased (P<0.05) the population of fecal E. coli compared with the NC treatment. In conclusion, results indicate that evening primrose extract can increase growth performance, CTTAD of DM, the population of fecal Lactobacillus, and decrease the LDL-cholesterol concentration and the population of E. coli. Evening primrose extract can be used as an alternative to antibiotic.

Keywords: evening primrose extract, growth performance, weanling pig