| Intramuscular fat(IMF)is an important indicator affecting the tenderness,flavor and juiciness of meat and it could be affected by many factors such as genetic,nutrition and gut microbiota.In the present study,we compared the performance of Duroc pigs from two lineages:59 normal pigs(IMF:1.5%～2.0%)and 59 EB5 pigs(IMF:5.0%～6.0%).We measured the growth performance,carcass character stic and meat quality traits(30 vs 30).Besides,we used the 80K liquid SNP chip for genotyping and the 16S rRNA gene sequencing for measuring of gut microbiota composition of Duroc pigs.The main results are as follows:(1)The IMF content of the progeny of EB5 Duroc pigs was significantly higher(2.3 8±0.73%vs 1.70±0.45%,p=6.23×10-5)and their growth rate(ADG:0.96±0.11kg/day vs 0.89±0.12kg/day,p=9.00×10-4),feed conversion ratio(FCR:2.41±0.17 vs 2.36±0.13,p=4.15×10-2),carcass weight(81.54±6.93kg vs 77.77±7.33kg,p=4.50×10-2),carcass length(102.37±0.27cm vs 100.90±2.79cm,p=2.10×10-3)and backfat thickness(23.28±4.19mm vs 20.89±3.46mm,p=1.9×10-2)were higher than the normal pigs.(2)The Duroc pigs was grouped by IMF content(high IMF and low IMF)at three level.Based on that,gradient selection signature analysis was used for the genetic analysis.A total of 563 SNPs were identified,which were from 66 genes.These genes were significantly enriched in the pathways of small GTPase mediated signal transduction(p=2.30×10-5),epithelial cell differentiation(p=2.57×10-5)and receptor signaling pathway via JAK-STAT(p=1.30×10-4),et al.(3)The intestinal microbial diversity of 160-day-old Duroc pigs was higher than that of 60-day-old Duroc pigs,and the Firmicutes and Bacteroides were the most abundant bacteria at phylum level,accounting for about 90%of the total.There were significant differences in the intestinal segments of Duroc pigs:the diversity of the large intestinal segments(cecum,colon)was overall higher than that of the small intestinal segments(duodenum,jejunum,and ileum)(p=1.32×10-5).The abundances of the Firmicutes and Proteobacteria showed significant differences in the two intestinal segments:the average abundance of the small intestinal Firmicutes phylum was 37.8%,the average abundance of the large intestinal Firmicutes phylum was 74.8%,the average abundance of the small intestinal Proteobacteria was 32.4%,and the average abundance of the large intestinal Proteobacteria was 5.8%.(4)The LEf Se method was used to identify differential microorganisms between high and low IMF content groups(three gradients)(LDA>4.0).It revealed that Oscillospirales in 160-day-old feces and Denitrificimonas_caeni of duodenum were more abundant in the low IMF group and Micrococcaceae were more abundant in the high IMF group.In addition,Lactobacillus in both 160-day-old and duodenal stools were more abundant in the high IMF group.This study showed that the offspring of Duroc boars with high IMF content of EB5 had obvious advantages in growth rate and meat quality traits,which provides valuable breeding materials for synergistic improvement of Duroc pigs’ growth and meat quality traits.We identified 66 potential genes and some of differential bacteria that may affect IMF content.It lays a foundation for the analysis of the genetic basis of IMF content and the interaction between genetics and gut microbiota. |
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