Effects of dietary supplementation with Artemisia argyi alcohol extract on growth performance, blood biochemical properties and small intestinal immune markers of broilers challenged with lipopolysaccharide

Context Broilers are prone to immunological stress when subjected to unsuitable environmental conditions (such as virus attack, nutrient deficiency and high stocking density), lowering immunity and resulting in inflammatory bowel diseases. The herb-feed additive Artemisia argyi has been applied in poultry production, and its extract may improve small intestinal immune capacity. Aims This study was conducted to investigate the effect of A. argyi alcohol extract (AAAE) on growth performance and blood biochemical and small intestinal immune markers of broilers challenged with a proinflammatory substance, lipopolysaccharide (LPS). The study also examined possible mechanisms of action, and aimed to clarify whether AAAE could be applied as a feed additive. Methods In total, 192 one-day-old Arbor Acres broilers were allocated to four groups following a 2 × 2 factorial arrangement (including six replicates with eight birds per replicate) with two dietary AAAE rates (0 or 750 mg/kg) and two immune stress treatments (LPS or saline injection). Blood and small intestine were sampled on Days 21 and 35. Key results Dietary AAAE alleviated the LPS-induced decrease in bodyweight, average daily gain and average daily feed intake, and mitigated the elevated serum alanine aminotransferase, triglyceride, low-density lipoprotein cholesterol, adrenocorticotropic hormone and corticosterone concentrations at Day 21 and/or Day 35 in LPS-challenged broilers. AAAE significantly (P < 0.05) attenuated LPS-induced increases in intestinal immunoglobulin (IgA, IgG and IgM) and interleukin (IL-1ß and IL-6) concentrations. Moreover, the small intestinal mRNA abundances of the genes TLR4, MyD88, NF-?Bp65, IL-1ß and IL-6 in LPS-challenged broilers were decreased (P < 0.05) in response to dietary AAAE treatment. Conclusions These results further demonstrated that AAAE at 750 mg/kg enhanced small intestinal tissue immune capacity of broilers, thereby alleviating LPS-induced immune stress damage in broilers. Its mechanism of action may be related to the mediating of TLR4/NF-?B pathways. Implications Dietary AAAE can be used to improve the immune function of broilers, and to provide a new scientific theoretical basis for the development of new anti-stress feed additives.