Impact of rare earth element-enriched yeast on growth performance, nutrient digestibility, blood profile, and fecal microflora in finishing pigs

This study was conducted to evaluate effects of rare earth element-enriched yeast (RY) on growth performance, nutrient digestibility, blood profile, and fecal microbial flora in finishing pigs. A total of 100 finishing pigs [(Landrace × Yorkshire) × Duroc] were used in a two-phase feeding trial. Pigs were randomly assigned to five treatments according to their initial body weight (five pens per treatment, two gilts and two barrows per pen). Treatments were basal diets, free of antibiotics [negative control (NC)]; NC + 500, 1000, and 1500 mg kg-1, respectively, of RY; antibiotics diets, NC + 500 mg kg-1 of tiamulin [positive control (PC)]. Overall, average daily gain (ADG) and gain to feed ratio (G:F) increased linearly with increasing level of RY in diets. At the end of the experiment, blood lymphocyte concentration and apparent total tract digestibility of dry matter and gross energy increased linearly in pigs fed the increasing level of RY in diets. The better ADG, G:F, and fecal Lactobacillus counts were observed in both RY and PC groups compared with the NC group. In conclusion, diets with RY improved growth performance, digestibility, blood lymphocyte counts, and fecal Lactobacillus counts in finishing pigs, and RY may be considered as an alternative to antibiotics.