Effect of an herb extract mixture on growth performance, nutrient digestibility, blood characteristics, and fecal microbial shedding in weanling pigs

A 6-week experiment was conducted to evaluate the effect of a dietary herb extracts mixture (HEM) on growth performance, nutrient digestibility, blood characteristics, and fecal microbial shedding in weanling pigs. A total of 144 pigs [(Landrace × Yorkshire) × Duroc] (BW = 7.6 ± 0.6 kg; weaned at d 21) were randomly allocated to 4 treatments according to their BW and sex (9 replicates of 4 pigs per treatment). Treatments followed a 2 × 2 factorial design with 2 levels of HEM (0 or 250 mg kg− 1 diet) and apramycin (0 or 30 mg kg− 1 diet). During the first week, pigs fed HEM supplemented diets led to a lower (P < 0.05) average daily feed intake (ADFI) but greater gain to feed ration (G:F) than those fed diets without HEM supplementation. Dietary HEM supplementation increased (P < 0.05) average daily gain (ADG) and G:F during 4 to 6 weeks. Antibiotics treatments showed greater (P < 0.05) ADG and G:F than those in non-antibiotics treatments from 0 to 1 week, 4 to 6 weeks, and the overall period. A decreased ADFI was observed (P < 0.05) when pigs were fed antibiotics supplement from 4 to 6 weeks. Pigs fed diets supplemented with HEM or antibiotic led to a higher (P < 0.05) DM and N digestibility at d 7. Dietary antibiotic increased (P < 0.05) N and energy digestibility at d 21. Antibiotic supplemented diets led to a higher (P < 0.05) DM digestibility in pigs at d 42. The coefficient of apparent total tract digestibility (CATTD) of DM and N was increased (P < 0.05) by HEM treatments at d 42 compared with non-HEM treatments. The blood lymphocyte concentration in HEM groups was greater (P < 0.05) than the non-HEM treatments at d 42. Pigs fed HEM supplemented diets had decreased fecal Escherichia coli concentration (P < 0.05) at the end of the current study. In conclusion, administration of HEM in weaning pigs diet had no effect on the growth performance during the whole experiment. However, the beneficial effect on nutrient digestibilities, lymphocyte and fecal E. coli concentration suggested that those kind of HEM have a positive role in weaning pigs.