Short communicationEffects of single-nucleotide polymorphisms in insulin-like growth factor-1 and insulin-like growth factor-2 genes on growth performance of centrally tested Duroc boars using segregated early weaning entrance
Introduction
The insulin-like growth factor (IGF)1 and IGF2 genes play important roles in normal fetal and postnatal growth and development, especially in myogenesis (Florini et al., 1996). Single-nucleotide polymorphisms (SNPs) in IGF1 and IGF2 were reported to be associated with growth performance and carcass traits in pigs (Li et al., 2003, Liu et al., 2003). Li et al. (2003) reported an SNP of IGF1 (IGF1-G201C; GenBank: NM_214256) in a Landrace × Lantang resource population and showed that IGF1-G201C significantly affected the average daily gain (ADG). Van Laere et al. (2003) showed that pigs inheriting a nucleotide substitution in intron 3 of IGF2 (IGF2-in3-G3072A) exhibited increased muscle deposition. Liu et al. (2003) reported two SNPs in intron 8 of IGF2 (IGF2-in8-C27222G and IGF2-in8-C27322G; GenBank: AY044828) in a Large White × Meishan reference family and found that these two SNPs explained a significant difference in fat deposition-related traits in boars. Vykoukalová et al. (2006) found that polymorphisms at IGF2-in3-G3072A and IGF2-in7-G162C showed significant effects on back-fat thickness and the lean-meat content of Large White pigs. Fontanesi et al. (2010) reported that the IGF2-in3-G3072A mutation is the polymorphism affecting fatness and muscle deposition, while other polymorphisms, like the cathepsin D CTSD-G70A polymorphism on SSC2p, could be used to increase selection efficiency in marker-assisted selection programs that already use the IGF2 mutation.
The segregated early weaning (SEW) procedure can limit vertical pathogen transmission from a dam to her piglets (Wilson, 1995) and has been adopted in central boar testing in Taiwan (Huang et al., 2008). Despite there being some reports showing SNPs in IGF1 and IGF2 and their association with growth performance in other breeds of pigs, few studies have been performed to investigate the effects of IGF1-G201C, IGF2-in8-C27222G, and IGF2-in8-C27322G polymorphisms on Duroc growth performance under the SEW protocol. This study investigated the effects of the SNP at IGF1-G201C and two SNPs at IGF2-in8-C27222G and IGF2-in8-C27322G on the growth performance of centrally tested Duroc boars using SEW entrance in Taiwan.
Section snippets
Source of animals and data collection
In total, 735 purebred Duroc boars from 11 herds around Taiwan were used. The boars were sent to the Central Testing Station at the Animal Technology Institute Taiwan (Miaoli, Taiwan) where a SEW entrance protocol was applied (Huang et al., 2008). The performance test was described in detail by Huang et al. (2008). All tested boars were fed the same diet ad libitum. At the end of the performance test, the age in days at the start of the test (SAGE), the ADG adjusted from 40 to 110 kg of body
Genotypic and allelic frequencies of SNPs in IGF1-G201C, IGF2-in8-C27222G, and IGF2-in8-C27322G of Doric boars in Taiwan
Frequencies of the IGF1-G201C, IGF2-in8-C27222G, and IGF2-in8-C27322G genotypes of Duroc boars are given in Table 1. Frequencies of the CC, CG, and GG genotypes in IGF1-G201C were 0.4%, 13.7%, and 85.9%, respectively. For the SNPs in IGF2-in8-C27222G and IGF2-in8-C27322G, no polymorphism in the IGF2-in8-C27222G locus was observed in this study. The frequencies of the GG, GC, and CC genotypes in the IGF2-in8-C27322G locus were 12.0%, 42.3%, and 45.7%, respectively. Frequencies of the G allele of
Conclusions
Results of this study suggest that the SNP in IGF1-G201C did not affect the growth performance of Duroc boars under the SEW testing protocol. However, the IGF2-in8-C27322G genotype significantly influenced the ADG, FCR, and A110. Thus the SNP can be used as a candidate genetic marker for improving the growth performance of Duroc boars under the SEW system.
Conflict of interest statement
The authors have declared no conflict of interest.
Acknowledgments
The authors would like to thank the Council of Agriculture (contract nos. 94AS-4.1.1-AD-U1(6), 95AS-5.1.1-AD-U1(16), and 96AS-2.1.1-AD-U1(7)) of the Republic of China for financial support of this research. We appreciate the technical assistance and data collection by Mr. Yu-Kwang Hu.
References (17)
- et al.
Association of polymorphism in alpha (1,2) fucosyltransferase gene with growth performance in two Western pig breeds in Taiwan
Livest. Sci.
(2008) - et al.
Effects of weaning and rearing environment on intestinal gene expression of IGF-I, IGFBP (1–6), and the IGF receptor and on specific binding of IGF-I to mucosal membranes in the pig
Gen. Comp. Endocrinol.
(2002) - et al.
Point mutation on intron 7 of IGF2 gene in pigs
- et al.
Detecting the polymorphisms of insulin-like growth factor-1 gene locus in six pig breeds
Anim. Husb. Vet. Med.
(1999) - et al.
Growth hormone and the insulin-like growth factor system in myogenesis
Endocr. Rev.
(1996) - et al.
The insulin-like growth factor 2 (IGF2) gene intron3-g.3072G>A polymorphism is not the only Sus scrofa chromosome 2p mutation affecting meat production and carcass traits in pigs: evidence from the effects of a cathepsin D (CTSD) gene polymorphism
J. Anim. Sci.
(2010) - et al.
A paternally expressed QTL affecting skeletal and cardiac muscle mass in pigs maps to the IGF2 locus
Nat. Genet.
(1999) - et al.
Genetic effects of IGF-1 gene on the performance in Landrace × Lantang pig resource population
Acta Genet. Sinica
(2003)