Transgenic plants have been tested as an alternative host for the production and delivery of experimental oral vaccines. Here, we developed transgenic potatoes that express the major antigenic sites A and D of the glycoprotein S from transmissible gastroenteritis coronavirus (TGEV-S0.7) under three expression vector systems. The DNA integration and mRNA expression level of the TGEV-S0.7 gene were confirmed in transgenic plants by PCR and northern blot analysis. Antigen protein expression in transgenic potato was determined by western blot analysis. Enzyme-linked immunosorbent assay results revealed that based on a dilution series of Escherichia coli-derived antigen, the transgenic line P-2 had TGEV-S0.7 protein at levels that were 0.015% of total soluble proteins. We then examined the immunogenicity of potato-derived TGEV-S0.7 antigen in mice. Compared with the wild-type potato treated group and synthetic antigen treated group, mice treated with the potato-derived antigen showed significantly higher levels of immunoglobulin (Ig) G and IgA responses.

Preventive and therapeutic effects of egg yolk antibody, immunoglobulin Y (IgY), against canine parvovirus (CPV) was evaluated in 25 pups orally challenged with CPV-2a. Oral administration of IgY using powder, paste and coated paste delivery systems was compared. Each type of IgY was administered orally for 17 days from 3 days before challenge. The group of pups administered coated IgY showed mild symptoms such as a moderate decrease in total white blood cell count, no depression, vomiting and diarrhea when compared with other groups. The overall clinical score of the group of pups administered coated IgY was significantly lower than that of the challenge control group. However, mortality did not differ among groups because not all pups received symptomatic treatment. These results implied that oral treatment of coated IgY could improve therapeutic effects against CPV challenge if pups received symptomatic treatment.

Norfloxacin (NFX) is a fluorquinolone antibacterial agent with a high antimicrobial activity and might have great potential for treating common infections in poultry. The objective of this study was to obtain comparative pharmacokinetic data after a single oral administration and medication with drinking water of norfloxacin-glycine acetate (NFX-GA) at the dose rate of 10 mg/kg bw in broilers. Fifty minutes following oral administration of NFX-GA, serum concentrations peaked at 1.32 ㎍/mL (range 1.03-1.45 ㎍/mL).