Novel SLA class I alleles of Chinese pig strains and their significance in xenotransplantation

To lay background for studying rejection mechanisms in xenotransplantation and developing the strategies for intervention, class I genes of swine leukocyte antigens (SLA) of three Chinese pig strains Bm, Gz and Yn were cloned and sequenced. The cDNA of the class I loci P1 and P14 were amplified by RT-PCR and subjected to insert into sequencing vectors. All six allelic sequences we examined, each two for one Chinese strain, are not identical to those reported, which allows these novel sequences receiving their accession numbers AY102467- AY102472 from GenBank. This study further reveals that the homologies of MHC class I genes in their primary structures and the deduced amino acids between Chinese pigs (SLA) and human (HLA-A*0201) are better than those between pigs and mice (H-2Db/H-2Kb). The comparison also indicates that the amino acid residues critical for recognition by human KIRs are altered in the swine class I molecules. The amino acids responsible for binding human CD8 coreceptor are largely conserved although there are two critical residues substituted. A functional test indicated that the human T cells specific for the prokaryotically expressed SLA Plprotein could respond quite well in vitro to the class I-positive swine chon-drocytes and PBMCs in presence of human APCs. This implies that, due to the substitution of two critical residues, the inaccessibility of human CD8 coreceptor to swine class I molecule might be contributable to the indirect pathway that the human T cells have to use for recognizing the SLA class I xenogeneic antigens.

Crossbreeding parameters for fertility traits in a rotational crossbreeding between Landrace and Piétrain pigs

The reproduction characteristics of 343 sows in six different breeding groups were analyzed to estimate the crossbreeding parameters. The results indicated that the ovulation rate and the weights of uterus and ovary are mainly determined by the additive genetic effects while the nonadditive genetic effects play an important role in embryonal traits and litter performance. The heterosis effects in the first litter are larger than those in the second litter because of heterosis x environment interaction. The results also showed the existence of a highly significant maternal heterosis effect on the fertility traits of sows.

Effects of inductive methods on dunging behavior of weaning pigs in slatted floor pens

The excreta of pig is generally utilized to induce pigs to excrete in particular area,which reduces the subsequent work required to clean pens.This paper discussed a new induction device design based on the biological characteristics of pigs.Using different induction materials in the devices,the frequency and location of the excretory behavior of pigs through five treatments and a control group were compared.According to the results,different induction methods had significant(p<0.05)effects on frequency and duration of excretory behavior.Compared to the conventional induction method,the induction devices were significantly(p<0.05)more effective in training pigs to excrete in the assigned area,the most effective material used in the induction devices was feces.If the inductive feces had been preserved in the air for a longer time,the effect of inducing excretory behavior would have been more obvious.Empty devices did not work to induce pigs to excrete in the induction area.