Challenge by various pathogens in overcrowded conditions of poultry are responsible for a large variety of disorders, resulting in immune stress, intestinal injure and subsequent compromise growth performance [1]. To prevent disease and guarantee growth of poultry, antibiotics had been widely used [2]. Following rise of customers’ attention to antimicrobial resistance issues, China commenced the ban of supplementing antibiotics in diets of poultry. As a result, phytogenic feed additives have been proposed to reduce the use of antibiotics in the poultry-farming industry [3].

Artemisia ordosica, also called Ordos Artemisia, Oil Artemisia or Hara Sibag, growing mainly in north and northwest areas in China, especially in Inner Mongolian district, is one of the main shrubby perennial belongs to Artemisia species of Asteraceae [4]. Medicinally, whole plant of Artemisia ordosica is used as an adjunctive therapy for dehumidification, detoxicating and detumescence by folk Chinese/Mongolian doctor [5]. Previous study revealed that Artemisia ordosica had therapeutic effect on inflammatory responses in xylene-induced ear swelling in mouse model and could alleviate effect against allergic rhinitis in guinea pigs [6]. Moreover, Artemisia ordosica showed antimicrobial activities in vitro [6]. Artemisia ordosica and its aqueous extracts contain many biologically active compounds, such as oils, flavonoids, terpenoids and saccharides [7]. Owing to great potential of Artemisia ordosica in producing valuable secondary products, there is a need to increase our knowledge on Artemisia ordosica extracts and their effects on livestock. It has been reported that Artemisia ordosica and their extracts can be used as feed additives to promote growth performance and enhance the immune function and antioxidant activity [4,8]. All of these studies demonstrate the ability of Artemisia ordosica and their extracts to suppress pro-inflammatory cytokine levels and alleviate oxidative stress.

An increasing number of researchers have been attracted by polysaccharide from the herb plants, on account of its potent immune-regulatory activity [9]. Moreover, plant-derived polysaccharides have been proved to treat/prevent immune stress through regulating TLR4/NF-κB pathway [9,10]. Our previous study also indicated that supplementation of AOP could alleviate oxidative stress through Nrf2/keap1 and TLR4/NF-κB pathway [11]. Collectively, we hypothesized that Artemisia ordosica polysaccharides (AOP) in poultry diets could alleviate immune stress and intestinal injury induced by lipopolysaccharide (LPS) of broilers. The endotoxin LPS is vital component of the outer coats in gram-negative bacteria. Orally or abdominally injected LPS can trigger immune stress reaction in the chickens due to the accumulation of pro-inflammatory cytokines, such as tumor necrosis factor-a (TNF-a), interleukin-1 (IL-1), and interleukin-6 (IL-6) when released excessively in the body [12,13]. Therefore, it is of great importance to develop new feed additives with therapeutic potential for alleviating LPS-induced immune stress in broilers. In this study, LPS intraperitoneal injection was used to establish immune stress model of chicks, so that the effects of AOP on growth performance, nutrients digestibility, levels of stress hormone, interleukin and immunoglobulin in serum, and immunity function and anti-oxidative capacities of jejunum in broilers challenged with LPS were investigated.