Effects of dietary Centella asiatica (L.) Urban on growth performance, nutrient digestibility, blood composition in piglets vaccinated with Mycoplasma hyopneumoniae

To investigate the effects of Centella asiatica (L.) on growth performance, nutrient digestibility and blood composition in piglets, 32 nursery pigs were fed 0.0, 0.5, 1.0 and 2.0% dietary C.asiatica (L.) from 15 to 90kg BW. At 30kg BW, nutrient digestibility was measured and at 35kg BW piglets were vaccinated with Mycoplasma hyopneumoniae. Hematological parameters were checked at 40 and 80kg BW. Compared with the control, growth performance was not affected. The ether extract, ash and calcium digestibility were lower at 0.5%, and dry matter, crude protein, crude fat, phosphorus and energy digestibility were lower at 1.0% (P<0.05). On hematological values, at 40kg hematocrit, total white blood cells, neutrophils, eosinophils, basophils, monocytes and lymphocytes were higher at the 2.0% level (P<0.05). Most of these values except basophils and monocytes continued until at 80kg, at which total white blood cells, neutrophils, eosinophils and lymphocytes were higher even at 1.0% (P<0.05); neutrophil-to-lymphocyte ratio tended to be higher at 2.0% (P<0.03). Cholesterol, triglycerides and antibody levels against M.hyopneumoniae did not differ except that at 40kg the cholesterol of 0.5% was lower (P<0.05) and M.hyopneumoniae-specific antibodies tended to be higher with increasing levels of C.asiatica (L.) (P<0.07). The result that C.asiatica (L.) could not improve growth performance but increased values of serum hematocrit and white blood cells, and mycoplasma immunity to M.hyopneumoniae might suggest that C.asiatica (L.) has no function to elevate body weight but has the potential to enhance innate immunity.