Construction and immunological evaluation of recombinant Lactobacillus plantarum expressing SO7 of Eimeria tenella fusion DC-targeting peptide.

The coccidiosis caused by Eimeria tenella (coccidian) and other species is a serious parasitic disease that affects the global poultry breeding industry. Lactobacillus strains exhibit a number of properties that make them attractive candidates as delivery vehicles for presentation to the mucosa of compounds with pharmaceutical interest, particularly vaccines. Here, the recombinant Lactobacillus plantarum (co-expressing SO7 and DCpep gene) was constructed, and its efficacy against E. tenella challenge was evaluated in this study. Broiler chickens were orally immunized with live recombinant L. plantarum NC8-pSIP409-SO7-DCpep for two weeks and were then challenged with 5×104E.tenella sporulated oocysts per chicken. During the experiment, body weight gains, cecum lesion scores, fecal oocyst shedding and antibody responses in serum and intestinal washes were assessed as measures of protective immunity. The results indicated that chickens immunized with live recombinant L. plantarum can increase body weight gains and serum antibody responses compared to the control groups. Meanwhile, fecal oocyst shedding in the immunized group was significantly reduced (p<0.01). Moreover, recombinant L. plantarum can significantly relieve pathological damage in cecum, according to lesion scores and histopathologic cecum sections (p<0.01). Therefore, these results indicate that recombinant L. plantarum NC8-pSIP409-SO7-DCpep could become a promising oral vaccine candidate against E. tenella infection.