Long-Term Protein Restriction Modulates Lipid Metabolism in White Adipose Tissues and Alters Colonic Microbiota of Shaziling Pigs

SIMPLE SUMMARY: The effects of prolonged protein deprivation on lipid metabolism in white adipose tissues and the gut microbiota of Shaziling pigs remain inadequately characterized. As an ideal obese model, the Shaziling pig is instrumental in studying obesity. This study was developed to examine the changes in lipid metabolism and the gut microbiota ecosystem induced by prolonged protein deficiency of Shaziling pigs and to explore the beneficial effects of low-protein diets for obesity management. After a 24-week trial, increased FABP4 mRNA abundance and PPARγ protein expression as well as decreased C/EBPα protein expression in dorsal subcutaneous adipose tissue and perirenal adipose tissue were achieved through a 20% reduction in the dietary protein level. At the same time, increased/decreased phosphorylation of AMPKα/mTOR were observed. Furthermore, reducing the protein level by 20% increased the relative abundance of the Lachnospiraceae XPB1014 group in the colon at the genus level. In summary, our findings indicated that long-term reduction in dietary crude protein by 20% positively impacted the lipid metabolism of Shaziling pigs. ABSTRACT: Obesity is a matter of concern to the public. Abundant evidence has been accumulated that nutritional intervention is a promising strategy to address this health issue. The objective of this study is to investigate alterations in the lipid metabolism in white adipose tissues and the gut microbiota of Shaziling pigs challenged by long-term protein restriction. Results showed that compared with the control group, reducing the protein level by 20% (−20%) increased the mRNA abundance of FABP4 in white adipose tissues (p < 0.05). This occurred in conjunction with increases in PPARγ protein expression. Conversely, the protein expression of C/EBPα was reduced in the −20% group (p < 0.05). Moreover, the −20% group had increased/decreased phosphorylation of AMPKα/mTOR, respectively (p < 0.05). As for the colonic gut microbiota, a 20% reduction in the protein level led to increased Lachnospiraceae XPB1014 group abundance at the genus level (p < 0.01). Collectively, these results indicated that a 20% protein reduction could modulate lipid metabolism and alter the colonic microbiota of Shaziling pigs, an approach which might be translated into a treatment for obesity.