Effects of Chinese herbal formula (including Houttuyniae Herba, Pulsatilliae Radix, Scutellariae Radix) supplementation in drinking water on growth performance, intestinal barrier function, and cecum microbiome composition of broilers under necrotic enteritis challenge.

We evaluated the antimicrobial activity of a Chinese herbal formula (CHF) (comprising Houttuyniae Herba, Artemisia Annua L., Pulsatilliae Radix, Radix Sanguisorbae, Aucklandiae Radix, Scutellariae Radix, Anemarrhenae Rhizoma, Semen Pharbitidis, and Radix Rhei Et Rhizome) and its protective effects against necrotic enteritis (NE) in broiler chickens. The in vitro results demonstrated significant antibacterial activity against Clostridium perfringens, as well as a positive effect of CHF on cell viability when exposed to this bacterium. In the in vivo experiments, 360 ten-day-old broilers were randomly assigned to six groups: control, NE, NE + lincomycin, NE + 2.5 g/L CHF, NE + 5 g/L CHF, and NE + 10 g/L CHF. The CHF-supplemented drinking water significantly improved the growth performance of the NE-challenged broilers. CHF supplementation improved intestinal barrier function and integrity in NE-challenged broilers by enhancing jejunal morphology, increasing the mRNA levels of tight junction proteins (zonula occludens-1 and occludin) and reducing intestinal permeability (serum D- lactic acid levels and diamine oxidase activity). Supplementation with the CHF also reduced systemic and jejunum pro-inflammatory cytokines (IL-1β, IL-6, IL-8, IL-17, TNF-α, IFN-γ) and increased anti-inflammatory factors (IL-4 and IL-10) in NE-challenged broilers by inhibiting the nuclear factor kappa B and signal transducers and activators of transcription signaling pathways. Cecal microbiota analysis revealed that supplementation with the CHF increased the abundance of beneficial bacteria (Faecalibacterium, Bacteroides, and Butyricimonas) in NE-challenged broilers. In conclusion, drinking water supplemented with the CHF enhanced growth performance, improved intestinal barrier function, and reduced systemic inflammatory responses in C. perfringens-challenged broilers. The recommended optimal dose of the CHF in drinking water is 5 g/L.