Study of the growth of the ventral nasal concha of the piglet by fluorescence Microscopy and Microradiography

Protection by toxoid-induced antibody of gnotobiotic piglets challenged with the dermonecrotic toxin of Pasteurella multocida

A crude dermonecrotic toxin (DNT) of Pasteurella multocida (P.m.) type D was prepared by repeated sonication and freezing. It was sterilized by filtration. A toxoid was then made and pigs were hyperimmunized with it to get an antiserum. A control serum was obtained by hyperimmunization of pigs with a preparation derived from nontoxigenic P.m. type D in the same manner as the toxoid. Three gnotobiotic piglets were injected with the antiserum. This resulted in neutralization indices (NI) of 25 in their sera, as tested on mice. Three litter-mated controls were given the control serum. Their NI remained 1. All piglets were challenged intramuscularly 4 times, every third day, with 30 mouse LD50 of the DNT. When euthanized 15 days after the last DNT administration no snout lesions were found in passively immunized piglets, whereas control animals showed severe turbinate atrophy and other changes typical for atrophic rhinitis. The next experiment was identical to the previous one except for the challenge, which was given intranasally (4 times 300 mouse LD50). Also in this case circulating antitoxin protected the piglets from damage of the nasal turbinates caused by the DNT.

Distribution of the mineralized tissues in the nasal ventral conchae (os conchae nasalis ventralis) of piglets after birth: relationship with atrophic rhinitis

Serial undecalcified cross sections were examined in order to establish the distribution of calcified cartilage, woven and lamellar bones in the nasal ventral conchae of piglets aged between birth and six weeks. The distribution of the mineralized tissues varied according to the age of the piglets and to the level of cross sections. The nasal ventral conchae were found to arise from an ossification center located at the level of the second premolar tooth. A correlation between the distribution of the different mineralized tissues of the nasal ventral conchae and the distribution of the lesions of atrophic rhinitis in the nasal ventral conchae as well as the receptivity period of piglets to the disease as observed in the literature have been discussed.