A bread-based lyophilized C-strain CSF virus vaccine as an oral vaccine in pigs.

A live attenuated cereal-based classical swine fever (CSF) vaccine for oral application, a form of vaccine that farmers can use themselves, demonstrated the improvement of CSF control in backyard production systems in endemic areas. Due to the dependency on very low storage temperature (-20°C) of the cereal-based oral CSF vaccine, a lyophilized cereal-based oral vaccine has been developed and tested. Although some studies showed total protection against a virulent virus strain, the production procedure is still considered complex. In this study, the lyophilized oral CSF virus, which is easy to produce and could be kept in the form of a bread-based vaccine at 4°C for an extended time, was tested for the ability to induce a humoral immune response in pigs. Among the materials tested as a base for the CSF virus vaccine, plain sliced bread was considered the most appropriate base because of its absorbing ability and virus titre maintenance. Titres of bread-based lyophilized CSF virus vaccine were stable at around 3.67 log10 TCID50 per ml for 7 months at 4°C. Pigs aged 5 and 8 weeks that orally received five bread-based lyophilized CSF virus vaccine showed seroconversion of over 90% at 14 dpv. At 28 dpv, both age groups showed 100% seroconversion. In conclusion, the bread-based lyophilized CSF virus vaccine can be an alternative choice for oral vaccination of pigs. Due to the simple process of production and the need for less virus titre, vaccine prices could be lowered. However, vaccine thermostability has to be improved to allow the vaccine delivery to be less dependent on functioning cool chains.

In vitro study of anti-coccidial activity of essential oils from indigenous plants against Eimeria tenella.

This study was designed to evaluate the in vitro anticoccidial properties against Eimeria tenella of different essential oils and their major active components. Efficacy of ten essential oils from different Thai indigenous plants were preliminarily screened and only those with potential were further tested for effective concentrations and identifying their active compounds. Oocysticidal property was evaluated in term of sporulation inhibition of oocysts and the percentage of unsporulated, sporulated and degenerated oocysts, after treatment with 125µg/ml of the selected essential oil, the sample was enumerated by haemocytometer, while coccidiocidal activity was assessed by the inhibition of sporozoite invasion in MDBK cell lines. Results showed that only Boesenbergia pandurata and Ocimum basilicum essential oils had strong sporulation inhibition activity by providing a higher ratio of degenerated oocysts and their IC50 were 0.134 and 0.101mg/ml, respectively. GC-MS analysis of B. pandurata essential oil found trans-b-ocimene, camphor, 1,8-cineole, geraniol, camphene, methyl cinnamate, l-limonene and linalool as the major components, while methyl chavicol, α-bergamotene, 1,8-cineole and trans-ß-ocimene were the main compounds of O. basilicum essential oil. Methyl cinnamate and camphor were the active components of B. pandurata oil, whereas methyl chavicol was the active component of O. basilicum oil by exhibiting the oocysticidal effect against E. tenella with IC50 values of 0.008, 0.023 and 0.054mg/ml, respectively. Furthermore, B. pandurata and O. basilicum oils also showed a strong cytotoxic property against coccidia with more than 70% inhibition of sporozoite invasion in MDBK cell lines, and their IC50 were 0.004 and 0.004mg/ml, respectively. Methyl cinnamate as well as camphor from B. pandurata and methyl chavicol from O. basilicum were also effective with IC50 values of 0.029, 0.023, and 0.022mg/ml, respectively.