The results of growth performance and microbial
populations have shown that with increased dosages of
P. oleracea extracts, more is not always better. Adding
0.2% P. oleracea extracts to broiler feeds improved
BWG and decreased FCR. The extracts could also increase
the populations of the beneficial bacteria Lactobacillus
and Bifidobacterium in the cecum and resulted
in a major reduction in E. coli. The growth-promoting
effect of P. oleracea extracts is related to its effect of
improving the intestinal microecology. However, there
may be some other mechanisms of which we are not
aware such as an anti-stress effect, which remain to be
confirmed by further study.