There is increased interest in using naturally occurring compounds subjected to new technologies for enhancing pig nutrition to replace antibiotic usage in swine production. The effects of ultrafine pulverization on the size distribution, morphology of Senecio scandens Buch.-Ham., and the growth performance, serum immunity parameters and faecal microorganisms of piglets fed this powder were investigated. The size distribution and morphology of S. scandens were characterized by using a laser diffraction analyser and scanning electron microscopy respectively. Ninety Duroc×Landrace×Yorkshire piglets (average body weight of 10.43kg) were randomly assigned to six treatments with three pens of five pigs per treatment. Group 1 (Control) piglets were fed the basal diet only. Groups 2 to 5 were fed with the basal diet supplemented with ultrafine powder (median diameter [d_0.5] of 8.89μm) of S. scandens at 0.3, 0.6, 0.9, and 1.2% of the basal diet, respectively, for 30 days. For group 6, 1.2% of ordinary S. scandens powder (d_0.5=88.59μm) was added to the basal diet. Both S. scandens ordinary and ultrafine powder increased piglet body weight and reduced the feed to gain ratio, but the performance of piglets fed the ultrafine powder was better. In groups 4 to 6, the number of Escherechia coli in faeces and the diarrhoeal incidence were significantly lower (P<0.05) and the serum IgA, IgG, IgM contents significantly higher (P<0.05). Feeding S. scandens ultrafine powder in the diet improved piglet performance and the diet supplemented with 0.9% of the ultrafine powder was the most effective.

Key words: Faecal microorganisms, Growth performance, Piglets, Scanning electron microscopy, Senecio scandens Buch.-Ham., Ultrafine pulverization