Plant extracts (PE) are secondary plant metabolites
In our previous in vitro study, all 7 different PE
tested, including the 3 PE tested here, had potential antiinflammatory
effects on porcine cells, as all of them inhibited
the secretion of tumor necrosis factor-α (TNF-α)
from lipopolysaccharide (LPS)-stimulated porcine alveolar
macrophages (Liu et al., 2012). Another experiment
showed feeding 10 ppm of capsicum oleoresin,
garlic botanical, or turmeric oleoresin enhanced immune
responses and growth efficiency of porcine reproductive
and respiratory syndrome virus (PRRSV)-infected
weaned pigs