Abstract
Background: Previous research has shown that exogenously short-chain fatty acids (SCFAs) infusion attenuated the body fat deposition in both mice, humans, and pigs. However, limited studies have evaluated the effects of SCFAs on lipid and glucose metabolism independently of the gut microbiota. Therefore, the present study was conducted to investigate the effects of exogenous infusion of SCFAs on lipid and glucose metabolism in a germ-free (GF) pig model. Methods: Twelve hysterectomy-derived newborn pigs were reared in six sterile isolators. All pigs were hand-fed Co60-γ-irradiated sterile milk powder for 21 days and switched from liquid to sterile solid feed for another 21 days. In the second 21-days period, GF pigs (n = 6) were orally infused with 25 mL/kg sterile saline per day, FA pigs (n = 6) were orally infused with 25 mL/kg SCFAs mixture (acetic, propionic, and butyric acids, 45, 15, and 11 mM, respectively) per day.Results: Orally infused with SCFAs tended to increase the concentration of adiponectin in serum, the activity of CPT-1 in longissimus dorsi, and the ANGPTL4 mRNA expression in colon (P < 0.10). Meanwhile, the mRNA abundances of ACC, FAS, and SREBP-1C in liver and CD36 in longissimus dorsi were decreased (P < 0.05), and the concentrations of ATP, ADP, or AMP in liver and longissimus dorsi were reduced (P < 0.05) in FA group. Besides, the mRNA expressions of PGC-1α in liver and LPL in longissimus dorsi were tended to (P < 0.10) increase and downregulate in FA group respectively. Moreover, the protein level of GPR43 was tended to increase (P < 0.10), and ACC was tended to decrease (P < 0.10), while the p-AMPK/T-AMPK ratio (P < 0.05) was upregulated in liver of FA group. Also, oral administration of SCFAs upregulated the mRNA expressions of SLC2a and GYS2 in liver (P < 0.05). Furthermore, the metabolic pathway associated with the biosynthesis of unsaturated fatty acids was significantly promoted (P < 0.05) by orally infused with SCFAs.Conclusions: Short-chain fatty acids could attenuate fat deposition and to some extent improve glucose control, and were occur independently of the gut microbiota.
Oral administration of short chain fatty acids could attenuate fat deposition of pigs
