Protection of Chickens from Mycoplasma gallisepticum through the MAPK/ERK/JNK Pathway by a Compound of Ten Chinese Medicine Formulas1

Abstract

Mycoplasma gallisepticum (MG) is a common avian pathogen that mainly infects poultry, causing significant reductions in body weight gain and egg production, along with damage to immune organs and immunosuppression. MG is susceptible to co-infections with other pathogens, leading to increased mortality rates and significant economic losses in the global poultry industry. While antibiotics have been extensively applied worldwide to treat MG infections in poultry production, concerns regarding antibiotic resistance and residue remain prevalent. Traditional Chinese medicine (TCM), renowned for its natural, safe, and non-toxic properties, has shown significant anti-inflammatory and immune-enhancing effects. This study aimed to investigate the protective effect of TCM on production performance and its impact on MG-induced immunosuppression through the MAPK/ERK/JNK signaling pathway in chickens. Our results showed that TCM alleviated the negative effects of MG infection on production performance, as evidenced by improvements in body weight gain, feed conversion rate, survival rate, and immune organ index. TCM exhibited direct inhibition of the MG proliferation in vitro and in vivo. Furthermore, TCM treatment promoted the normalization of trachea and lung tissue structure in MG-infected chickens, leading to a significant reduction in inflammatory damage. Moreover, following the treatment with the TCM, the production of pro-inflammatory cytokines Interleukin-1β (IL-1β) and Tumor Necrosis Factor-α (TNF-α) decreased significantly, accompanied by the downregulation of pro-apoptotic genes caspase3, caspase9, and BAX, both in vitro and in vivo. A mechanism-based study showed that in vitro and in vivo treatment with the TCM significantly reduced the expression of key proteins, including early growth response gene1 (EGR1), p-ERK, p-JNK, and p-JUN. Altogether, TCM improved body weight gain, inhibited pro-inflammation responses, and alleviated tissue damage by inhibiting the MAPK/ERK/JNK signaling pathway to protect the performance and immune system of MG-infected chickens.