Abstract
The experiment was conducted to assess the effect of fumaric acid supplementation on the performance of starter pigs and on the microbial population appearing in their feces. Seventy seven crossbred (LWD) piglets produced by 8 sows were weaned at 3 weeks of age and allotted to the control group of 39 head and the test group of 38 head. The weanling pigs fed a solid milk replacer for 2 weeks and a starter pig diet for 4 weeks. They were compared with pigs fed similar diets supplemented with 3% fumaric acid. During the 6-week feeding trial, supplementation of fumaric acid to the diets improved (p<0.01) weight gain. The average daily gain was 14% greater for pigs fed diets supplemented fumaric acid. Feed conversion efficiency also improved 6% but could not find statistical significance. There was no difference in viable counts of coli-form bacteria assayed in the feces of two groups, and no difference in those of fumaric acid-utilizing anaerobes. Gram staining of fumaric acid-utilizing anaerobes revealed that these microbes consisted of gram-negative small cocci and gram-negative large cocci. The former anaerobe produced large amount of propionic acid and small amount of acetic acid from fumaric acid in a liquid medium. On the other hand, the latter anaerobe produced various acids including acetic, propionic, isobutyric, butyric, isovaleric, valeric and caproic acids in the same medium. These findings suggested that the former shoud be Veillonella species and the latter Megasphaera species.
