Genetic resistance towards Salmonella infection in pigs

A PCR-RFLP of intron 1 and intron 2 of the Nramp1 gene described as a potential candidate gene in controlling pig resistance to Salmonella infections was optimised and an association between the Salmonella status and the polymorphisms was investigated. For intron 1 new primers were designed and the amplicon of 622 bp was restricted with Hinf I to give fragments of 280 bp, 220 bp and 100 bp for allele A and 76 bp, 100 bp, 144 bp, and 280 bp for allele B. For intron 2 a new polymorphism was detected (a deletion) with fragments of 210 bp and 199 bp after amplification respectively for allele A and B. The frequency of allele B and A was 0.93 and 0.90 on a total of 180 and 205 pigs for the polymorphism in intron 1 and intron 2 respectively in a mixed population of hybrid and purebred pigs. Similar allele frequencies of allele B and A of 0.90 and 0.91 respectively in intron 1 and intron 2 were found in a sample of 392 and 391 slaughter pigs. In the latter population, no association between the Nramp1 genotypes and the colon Salmonella status or the ELISA status could be demonstrated.