Since the ban on antibiotics in feed, intestinal health issues have become a serious challenge facing the breeding industry, causing huge economic losses to farmers. The synergistic effect of various probiotics in Active-4 is that on the one hand, they compete for the nutrients and living space of pathogenic bacteria, inhibiting their growth and reproduction; on the other hand, it can regulate the acid-base balance in the intestine, create a good growth environment for beneficial bacteria, promote their rapid proliferation, and thus enhance the immune defense function and digestion and absorption capacity of the intestine. This multi-dimensional effect of improving the intestinal microecological environment has effectively alleviated the farming difficulties caused by intestinal health problems after the ban on antibiotics, helping farmers stabilize production and improve farming benefits.