VFA metabolism in the pig.

Blood plasma concentrations of volatile fatty acids (VFA) in the carotid artery, and the femoral, portal and hepatic veins were measured in pigs fed a low carbohydrate diet (LC group, n=3), and in those fed a high carbohydrate diet (HC group, n=4). The mean body weights at the sampling time were 33.1 for the LC group and 42.2 kg for the HC group. The hepatic endogenous production of not only acetate, but of also propionate and butyrate was found, and it was suggested that the net hepatic endogenous production of VFA in the LC group was higher than that in the HC group. The arteriovenous differences in acetate concentration across the hind limb and the portaldrained viscera suggested that the acetate uptake in both tissues was higher in the LC group than in the HC group. A comparison between the portal appearance of VFA and its absorption from the large intestine showed that a large proportion of VFA from the large intestine was metabolized during absorption, and consequently, endogenous VFA seemed to be the important contributor to the VFA circulating in the general body tissues of the pig. (