Novel Vitronectin Variations and Their Comparative Analysis in Six Porcine Breeds

SIMPLE SUMMARY: Feed efficiency strongly influences the productivity and profitability in modern swine farming enterprises. Residual feed intake (RFI) as a measure of feed efficiency has been extensively studied, which is defined as the differing value between observed feed intake and expected feed intake based on growth and backfat. There is a potential that the porcine vitronectin plays a role in RFI through affecting the energy metabolism within muscles. Using sequencing technology, we found that rich variations and amino acid changes existed in key regions of vitronectin. In addition, a difference in variant frequencies was observed between local Chinese breeds (Sujiang, Jiangqu-hai, and Jiaxing-black) and three well characterized breeds (American Duroc, Canadian Duroc, and Berkshire) derived from the overseas. We suggest that the porcine vitronectin gene can be studied further and may be developed as a gene marker to select high feed-efficiency swines. ABSTRACT: Vitronectin plays a role in the blood homeostasis and has been implicated in cell adhesion, migration, and proliferation. Vitronectin has a potential role affecting the residual feed intake (RFI) or feeding efficiency in swine production. Its variations have not been reported in Chinese swine breeds. In this study, two regions of porcine vitronectin were analyzed using PCR and sequencing. The sequence analysis revealed thirteen nucleotide substitutions in region 1 (exon 2- exon 3) and three nucleotide substitutions in region 2 (exon 5- intron 5), which would result in five amino acid changes (p.Ala52Thr, p.Leu94Pro, p.Leu94Gln, p.Gln94Pro, and p.Glu126Gly). In region 1, c.156C/T, c.281A/T, and c.377A/G were the most common (at a total frequency of 49.3%, 31.3% and 31.9% respectively), whereas c.153C/T and c.180C/G were rare (at a total frequency of 1.39%). In region 2, c.597 + 12A/G was the most common (at a total frequency of 39.6%), followed by c.597 + 15A/G (at a total frequency of 31.3%) and c.459A/G (at a total frequency of 16.0%). There was a difference (p < 0.05) in variant frequencies between Chinese breeds and overseas breeds. These results indicate that the porcine vitronectin gene is polymorphic and suggest further analysis is required to see if the variation detected affects RFI or feed efficiency in swines.