Effects of dietary supplementation of fulvic acid on lipid metabolism of finishing pigs.

The experiment was conducted to investigate the effects of dietary supplementation of fulvic acid on lipid metabolism of finishing pigs. One hundred eighty crossbred barrows (Landrace x Yorkshire, 60 +/- 2.5 kg) were randomly allotted to 5 dietary treatments (36 pigs/treatment) and fed a basal diet supplemented with 0, 0.2%, 0.4%, 0.6%, and 0.8% fulvic acid for 42 d. Thirty pigs (6 pigs/ treatment) were slaughtered at the end of the experiment. Blood samples and adipose tissue were collected for determination of blood parameters and lipid metabolic enzymes. The results showed that compared with the control group, dietary supplementation of 0.2%, 0.4%, and 0.6% fulvic acid significantly reduced mean backfat thickness of pigs (P < 0.05). The serum concentrations of low-density lipoprotein, leptin, growth hormone, insulin, and triiodothyronine were significantly increased by adding fulvic acid in diets (P < 0.05). With the raised concentration of dietary fulvic acid, hormone sensitive lipase (HSL) activity was significantly increased (P < 0.05), and lipoprotein lipase (LPL) activity was significantly decreased (P < 0.05) in adipose tissue. In conclusion, dietary supplementation of fulvic acid reduced the mean backfat thickness of pigs. This change related to the increased activity of HSL and the decreased activity of LPL in adipose tissue.