Effects of mycoplasmal pneumonia of swine (MPS) lung lesion‐selected Landrace pigs on MPS resistance and immune competence in three‐way crossbred pigs

Abstract

To clarify the genetic influence of mycoplasmal pneumonia of swine (MPS) lesion-selected Landrace (La) on MPS resistance and immune characteristics in three-way crossbred pigs (LaWaDa), the LaWaDa pigs were compared with the non-selected crossbred (LbWbDb) and purebred (La) pigs. The MPS lesion score in the three lines was as follows: La line < LaWaDa line < LbWbDb line, with significant differences among the lines. The proportions of myeloid cells and T cells were lower and higher, respectively, in the LaWaDa pigs compared with those in the other two lines. Messenger RNA (mRNA) expression of interleukin (IL)-6, IL-10, transforming growth factor-β, and interferon-γ in peripheral blood was significantly increased after vaccination in the La and LaWaDa lines. IL-4 mRNA expression in the LaWaDa line was intermediate to the La and LbWbDb lines. Furthermore, principal component analysis for immune traits and MPS lesions was executed to clarify the characteristics of each pig line. These findings suggest that the immune responses in the three pig lines are genetically distinct and that MPS resistance and some immunity characteristics from the La line were transmitted to the three-way crossbred pigs.

IL‐12p40 gene expression in lung and hilar lymph nodes of MPS‐resistant pigs

“…Previous reports by Katayama, Shimazu and Borjigin (Borjigin et al, 2016;Katayama et al, 2011;Shimazu et al, 2013Shimazu et al, , 2014 pigs. Borjigin also reported that the immune responses in MPSselected landrace pigs and other pig mix-breed lines were genetically distinct (Borjigin et al, 2017).…”

“…Previous reports by Katayama, Shimazu and Borjigin (Borjigin et al., 2016; Katayama et al., 2011; Shimazu et al., 2013, 2014) suggested that MPS‐selected landrace pigs had different immunological reactions, which depend on immunophenotype with experiments of injection of sheep red blood cells (SRBCs) or vaccination against M.hp, compared non‐treated pigs. Borjigin also reported that the immune responses in MPS‐selected landrace pigs and other pig mix‐breed lines were genetically distinct (Borjigin et al., 2017).…”

“…) or vaccination against M.hp, compared non-treated pigs. Borjigin also reported that the immune responses in MPSselected landrace pigs and other pig mix-breed lines were genetically distinct(Borjigin et al, 2017). Neutrophils are generally observed in the inflammatory exudate of the porcine lung infected with M.hp(Kubo & Ishikawa, 2009; …”