Background  The minipigs is considered an ideal animal model for studying Atherosclerosis (AS) due to its similarities to humans in terms of the anatomy and hemodynamics of the coronary artery. However, there is a lack of research on the alterations in intestinal flora in minipigs with AS.

Objective  The 16S rRNA gene sequencing technology was used to analyze the changes in the intestinal flora spectrum of the minipigs AS model.

Methods In this study, eight 6-month-old male minipigs were randomly divided into model groups (AS group=4) and control groups (Ctrl group=4). The minipigs in the AS group were fed a high-cholesterol and high-fat diet for 9 months to establish the AS model, and the minipigs in the Ctrl group were fed a normal feed diet for 9 months. The minipigs in both groups were weighed monthly to calculate the weight growth rate. After 9 months of modeling, whole blood was collected and separated serum was fasted for 16 hours for detection of blood lipids; minipigs were anesthetized and sacrificed, and abdominal aortic plaques were collected for pathological examination. The colon contents were collected and sequenced for the V3-V4 region of the 16S rRNA gene to analyze the characteristics of the intestinal flora of AS minipigs.

Results The weight growth rate of minipigs in the AS group from 1 to 9 months was significantly higher compared to the Ctrl group (all P<0.05). Blood lipids showed a significant increase at 9 months (P<0.05), and typical atherosclerotic plaques were observed in the intima of the abdominal aorta. The Observed species results (P=0.228), Chao1 results (P=0.214), Simpson results (P=0.356), and Shannon results (P=0.089) of the intestinal flora of minipigs in the Ctrl group were higher than the AS group, although not significantly different. PCoA results (P=0.027) and NMDS results (P=0.027, Stress=0.03) showed significant differences in the intestinal flora of the two groups. The predominant intestinal flora of the AS group included Escherichia-Shigella, Ruminococcaceae-UCG-005, Lachnospiraceae-unclassified, Muribaculaceae-unclassified, and Bacteroides; while the Ctrl group had Ruminococcaceae-UCG-005, Clostridium, Lachnospiraceae-unclassified, Muribaculaceae-unclassified, and Rikenellaceae-RC9-gut-group as predominant flora. The proportions of Firmicutes/Bacteroidetes were significantly reduced in the AS group (P=0.018). The functional pathways of the intestinal flora in both groups were mainly focused on metabolic pathways involving amino acids, sugar, vitamins, Cytochrome C, and tricarboxylic acid metabolism

Conclusion The Bama minipigs AS model, established on a high-cholesterol and high-fat diet, exhibited characteristics of obesity and the development of typical atheromatous plaque lesions in the abdominal aorta intima. The presence of these lesions could be linked to the structural imbalance of the intestinal flora.