Genetic association of swine leukocyte antigen class II haplotypes and body weight in Microminipigs

Abstract

Objective: Microminipigs are a novel animal model with extensive applications in laboratory studies owing, in part, to their extremely small body sizes. In this study, the relationship between swine leukocyte antigen (SLA) class II haplotype and body weight was evaluated in the Microminipig population. Methods: A total of 1,900 haplotypes, covering SLA class II haplotypes Lr0.7, Lr0.23, Lr0.17, Lr0.37, Lr0.16, Lr0.11, Lr0.13, and Lr0.18, were analyzed in 950 piglets. Birth weights and weights on postnatal day 50 were examined in piglets with eight different SLA class II haplotypes. Results: The mean birth weight of piglets with the Lr0.23 haplotype (0.415 kg, n = 702) was significantly lower than that of piglets with Lr0.17 (0.445 kg, n = 328) and Lr0.37 (0.438 kg, n = 383) haplotypes. At postnatal day 50, the mean body weight of piglets with the Lr0.23 haplotype (3.14 kg) was significantly lower than that of piglets with the Lr0.13 haplotype (3.46 kg, p<0.01). There were no significant differences in daily gains (DGs) among the eight haplotypes. However, piglets with the Lr0.11 and 0.18 haplotype combination or any heterozygous haplotype combinations containing Lr0.23 had significantly lower DGs than those of piglets with the Lr0.18, 0.37 haplotype combination. Conclusion: Piglets with the Lr0.23 haplotype had relatively low body weights at birth and on postnatal day 50 and slightly lower DGs than those of piglets with other haplotypes. Therefore, the Lr0.23 SLA class II haplotype may be a suitable marker for the selective breeding of Microminipigs with small body sizes.