Effects of herbal extract on growth performance, fecal microbiota, nutrient digestibility, and blood profiles in weanling pigs

An experiment was conducted to evaluate the effect of dietary supplementation with herbal extracts (HE) on performance, apparent nutrient digestibility, microbial shedding, and blood characteristics in weanling pigs. A total of 120 weaned barrows with average initial BW of 6.93 ± 0.85 kg were included in this 35-d feeding trial. Pigs were randomly distributed into one of four treatment groups on the basis of BW and litter (5 pigs,pen, 6 replicate pens,treatment). Dietary treatments were: 1) negative control (NC), corn-soybean basal diet, 2) antibiotic control (PC), basal diet with antibiotics, 3) basal diets with herbal extract 0.5 g,kg (HE0.5), and 4) basal diets with herbal extract 1 g,kg (HE1). During the experimental period, average daily gain (ADG) were higher (linear effect, P<0.05) in PC and HE1.0 group, whereas average daily feed intake (ADFI) were unaffected by dietary treatment. The pigs fed diet supplemented antibiotics and HE were higher than those fed the NC diet in gain,feed (G,F) during the whole experiment, and a linear effect were be observed in HE treatments (P<0.05) as the levels of HE increased. Administration of HE1 and PC increased (P<0.05) the digestibility of dry matter (DM) and nitrogen throughout the whole experiment. The number of E. coli linearly decreased with increasing levels of HE (P<0.05) at d 35. Additionally, HE linearly increased the number of Lactobacillus at d 21 (P<0.05), while no effect was observed in PC treatment. The fecal pH values were not influenced by the dietary treatment. The white blood cell in the blood was increased (P <0.05) in both PC and HE compared with the NC treatment at d 35, with the highest values in HE1 treatment. Moreover, the serum immunoglobulin G (IgG) were linearly increased as the HE levels increased (P<0.05) at d 7, 21, and 35. And pigs fed the PC diet had higher IgG concentration than the control group only at d 35. In conclusion, the addition of HE and PC can improve the performance, inhibition the proliferation of E.coli, as well as modulating the immune-related cells in the blood.