The anti-inflammatory and antioxidant effects of leonurine hydrochloride after lipopolysaccharide challenge in broiler chicks

This study was carried out to investigate the protective effects of leonurine hydrochloride (LH, from Leonurus sibiricus) on lipopolysaccharide (LPS)-stimulated broiler chicks. A total of 120 one-day-old male Ross broilers were randomly divided into 4 treatment groups with 6 replicates of 5 birds per cage. The experiment was designed as a 2 × 2 factorial arrangement with LH (0 or 120 mg/kg) and LPS (injection of saline or 1.5 mg/kg body weight) levels as treatments. On days 14, 16, 18, and 20 of the trial, broilers were intraperitoneally injected with LPS or saline. Blood, spleen, and liver samples were collected on days 21 and 28 for analysis. The results showed that dietary LH had no effect on growth performance or immunoglobulin concentrations in the serum. However, dietary LH prevented LPS-induced reductions in average daily gain and average daily feed intake in the broilers on days 15-21 of the trial (P > 0.05). Dietary LH supplementation dramatically attenuated the LPS-induced increases in the spleen index, reduced glutathione (GSH) activity (serum and liver) and total superoxide dismutase (T-SOD) activity (serum and spleen), and significantly reduced malondialdehyde (MDA) levels (serum, spleen, and liver) on days 21 and 28 (P < 0.05). Additionally, LH supplementation significantly mitigated the LPS-induced increases in the tumor necrosis factor (TNF)-α (serum and spleen), interleukin (IL)-1β (serum, spleen and liver), IL-2 (liver), IL-6 (serum, spleen and liver), toll-like receptor 4 (TLR4) (spleen and liver), and nuclear factor (NF)-κB (spleen and liver) levels on days 21 and 28 (P < 0.05). Therefore, this study revealed that LH could downregulate the expression of proinflammatory factors, mainly by inhibiting the expression of TLR4 and the activation of NF-κB. LH may be a potential feed additive with dual efficacy as an anti-inflammatory and antioxidant agent.