Assignment of the SLA alleles and reproductive potential of selective breeding Duroc pig lines.

BACKGROUND: Pigs with defined swine leukocyte antigen (SLA) haplotypes and their detailed information are useful for transplantation and immunological studies. We developed two herds of SLA homozygous Duroc pigs with novel SLA haplotypes and characterized their reproductive potential. METHODS: For selective inbreeding, a pair of Duroc pigs was chosen as initial breeders, and substantial breeding within progenies was carried out for eight generations. In the selective breeding Duroc pigs, SLA haplotypes were assigned by nucleotide sequence determination of reverse transcription polymerase chain reaction (RT-PCR) products of three SLA classical class I genes and two class II genes. Based on this sequence information, we developed a rapid and simple SLA class II DNA typing method by polymerase chain reaction-sequence specific primer (PCR-SSP) technique. As a complementary method for the characterization of the SLA haplotypes, genetic polymorphisms of 36 microsatellite (MS) markers within the SLA region were also analyzed in the selective breeding pigs with SLA homozygous/heterozygous haplotypes. RESULTS: Among the selective breeding pigs from the third to fifth generations, only two SLA haplotypes were identified by the RT-PCR based SLA typing method; Hp-27.30 (SLA-1*08an03, SLA-1*06an04, SLA-2*0102, SLA-3*0101 DRB1*1101 and DQB1*0503) and Hp-60.13 (SLA-1*an02, SLA-2*1002, SLA-3*0502, DRB1*0403 and DQB1*0303). In these two SLA haplotypes, two class I haplotypes, Hp-27.0 and Hp-60.0, are novel. Furthermore, two class II haplotypes, Hp-0.30 and Hp-0.13, which were previously reported in Korean native pigs and pigs of Hanford breed, respectively, were also assigned by a simple assay using a PCR-SSP technique in the entire selective breeding stock. Moreover, two haplotype specific MS patterns were observed across the entire SLA region in the selective breeding (homozygous/heterozygous) pigs. No morphological abnormalities were observed in selective breeding pigs. The theoretical inbreeding coefficient at the eighth generation was 78.5%. In all generations of selective breeding pigs, litter sizes were comparable and weaning weights from the fifth to eighth generation produced progenies significantly lighter (P < 0.01) than those in the non-selective breeding pigs. CONCLUSIONS: We established and characterized SLA homozygous Duroc herds with two kinds of haplotypes that can be used as a new resource for transplantation and other biomedical studies.

Cloning, expression and investigation for polymorphisms of canine peroxisome proliferator-activated receptors.

Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors implicated in lipid metabolism. In this study, the full-length cDNA of canine PPARbeta and gamma were sequenced, and expression of PPARs was evaluated in normal tissues and primary cultures of adipocytes in dogs, followed by investigations for polymorphisms of canine PPARgamma. Comparison of the deduced amino acid sequences of canine PPARbeta and gamma cDNA with that of human PPARbeta and gamma cDNA revealed 95.9% and 98.2% identity, respectively. PPARbeta expression was ubiquitous and high PPARgamma expression was detected in the subcutaneous and omental adipose tissues, spleen and large intestine. Canine PPARgamma mRNA expression in cultured adipocytes began to increase from 4 days after induction of differentiation, and increased nearly ninefold within 10 days after induction of differentiation. Although expression level of PPARalpha was low in the cultured adipocytes, it slightly increased within 10 days. In contrast, expression of PPARbeta showed only small variations during adipocyte differentiation, though expression levels were relatively high. These results suggest that PPARgamma may play an important role in adipocyte differentiation in dogs. Investigations for polymorphisms of PPARgamma revealed a silent polymorphism, C1362T, in 3 of 92 dogs.