Herbal-Probiotic Feed Additive Reduced Colitis Markers in Hu Sheep
A three-part feed preparation built around glycyrrhizic acid, Isatidis folium extract, and Bacillus subtilis lowered inflammatory injury in a Hu sheep model of colitis and improved several markers tied to intestinal barrier integrity. The work is framed around a pressing problem in young animals: weaning stress, dietary transition, and maternal separation can destabilize the gut and drive diarrhea or enteritis at the very age when growth potential matters most.
In practical terms, the study asked whether a compound preparation could do what antibiotics have long been asked to do in livestock production without carrying the same resistance burden. The answer was not based on a single endpoint. Instead, it came from a chain of findings that linked bacterial inhibition, immune modulation, and preservation of the colonic mucosa.
In Vitro Antibacterial Activity Pointed to a Complementary Formulation
Before turning to the lambs, investigators tested whether the herbal components interfered with the growth of B. subtilis. They did not. Glycyrrhizic acid and Isatidis folium extract did not affect the growth of the probiotic organism, a useful detail because a feed additive that suppresses its own microbial partner would undercut the entire strategy.
The combined preparation behaved differently once pathogenic bacteria entered the picture. The compound preparation significantly inhibited the growth of Escherichia coli and Staphylococcus aureus, suggesting that the herbal and probiotic elements may complement one another rather than compete. Biologically, that makes sense: the plant-derived components are positioned to dampen inflammatory signaling and suppress pathogenic growth, while the probiotic component supports a healthier intestinal ecosystem and may help preserve mucosal defenses.
Growth and Immune Changes Emerged in the Lamb Feeding Study
Twenty-seven 45-day-old healthy male Hu lambs were assigned to three dietary groups: a basal diet, 25 g of compound preparation per kilogram of diet, or 30 g per kilogram of diet. In that feeding phase, CP1 significantly increased daily weight gain. Both CP1 and CP2 increased serum immunoglobulin G and colonic mucosal secretory immunoglobulin A, two readouts that matter because systemic and mucosal immunity often move in different directions when gut health improves.
The immune profile shifted along with those gains. CP1 and CP2 increased the relative mRNA expression of interferon γ, interleukin-1β, interleukin-4, interleukin-6, and interleukin-10. Those cytokines do not point in a single direction; rather, they reflect an immune system that is being actively engaged rather than simply suppressed. In a production-animal context, the value lies in balance. A gut that can respond robustly without tipping into uncontrolled inflammation is better positioned to maintain feed efficiency and barrier function.
One sentence captures the core signal: the lower-dose formulation produced the clearest growth benefit.
DSS Colitis Was Blunted by the 25 g/kg Diet
The protective study was more direct. Eighteen 45-day-old healthy male Hu lambs were assigned to three groups: basal diet alone, basal diet plus dextran sulfate sodium, or basal diet plus 25 g of compound preparation per kilogram followed by dextran sulfate sodium exposure. In the CP-DSS arm, the preparation significantly downregulated proinflammatory cytokine expression, including interferon γ, interleukin-1β, and interleukin-6.
At the same time, the same diet upregulated anti-inflammatory cytokines and barrier-associated factors. Interleukin-4 and interleukin-10 increased, along with ZO-1, occludin, Muc2, and α-catenin. Those molecules sit at the center of epithelial defense. ZO-1 and occludin help tighten junctional sealing between cells, Muc2 supports the mucus layer, and α-catenin contributes to junctional architecture. When those defenses are restored, the colon is better equipped to resist leakage, invasion, and the cascade of damage that follows barrier failure.
The histologic consequence was visible: the compound preparation alleviated colonic damage. In a disease model driven by mucosal injury, that is not a trivial finding. It suggests that the formulation does more than reduce symptoms on paper; it reaches the tissue level where colitis actually unfolds.
Why the Combination Matters at the Bedside of Animal Production
The appeal of this approach lies in its structure. Glycyrrhizic acid brings anti-inflammatory and immunomodulatory activity. Isatidis folium extract contributes anti-inflammatory and detoxifying effects. Bacillus subtilis supports the intestinal microecology and feed utilization. In combination, the ingredients appear to hit multiple steps in the pathogenesis of enteritis: microbial burden, mucosal inflammation, immune tone, and epithelial permeability.
That multi-pronged action is particularly relevant in lambs, where gut injury can quickly translate into diarrhea, weight loss, and broader production losses. The finding that the lower dose improved daily weight gain while the colitis model showed protection with the same 25 g/kg diet gives the formulation a coherent profile. Higher is not automatically better in feed biology, especially when the target is gut homeostasis rather than maximal pharmacologic suppression.
The study does not claim the problem is solved. The work was conducted in Hu sheep under controlled conditions, and the protective effect was demonstrated in a DSS-induced model rather than in naturally occurring field enteritis. Even so, the data are strong enough to support further development of this antibiotic-free feed additive as a candidate for intestinal health management in sheep, with the caveat that real-world use still needs to be measured against farm conditions, diet variation, and longer-term safety.