Influence of Fumaric Acid Administration on Intestinal Microorganisms in Weanling Pigs

Abstract

An experiment was conducted to investigate the effect of fumaric acid supplemented to the diets on the population of intestinal microorganisms and their fermentation in weanling pigs.
Fourteen pigs at a litter were weaned at 21 day old and they were divided into two groups which were given weanling diets with or without fumaric acid in the level of 3%. The diets were prepared without antibiotics. The pigs of each group were killed at 8, 9 and 10 week old in the order of 3, 2 and 2 head. The digesta of the stomach, the small intestine, the cecum and the colon were sampled and analyzed for pH, VFA, coliform bacteria and fumaric acid utilizing anaerobes.
The pH of gastrointestinal contents was not affected with fumaric acid administration although a trend to lower pH was found in the duodenum, the jejunum, the ileum, and the colon. The viable counts of coliforms on DHL plate ager medium indicated that the fumaric acid treatment depressed the colonization of this bacteria in the lower ileum, the cecum and the colon and the difference of treatment vs. control was significant in the ileum and the colon (p<0.01) and the cecum (p<0.05). The specimens picked up at random from 19 colonies were identified all as Escherichia coli. The anaerobes appeared in Veillonella medium were Gram-negative small cocci in clusters and Gram-negative large cocci occurring in pairs. The former was decided as Veillonella species and the latter as Megasphaera spp. It could be pointed out that the concentrations of Veillonella spp in the lower ileum and the cecum of treated group were higher compared with those of control group, and the Megasphaera spp was also in the state similar with the Veillonella spp in the treatment vs. control relations. The determination of molar proportions of VFA in the ileal, the cecal and colonic contents showed that propionic acid was the most predominant one of VFAs appeared in the three portions of weanling pig. This fact seemed to reflect the function of VeilLonella spp inhabiting predominantly in these portions in order of 106 levels. The other finding was the relatively high proportions of iso-butyric and iso-valeric acids in the cecum and the colon. These facts suggest that the microbial fermentation occurring in the cecum and the colon is somewhat different from the fermentation in the ileum in weanling pigs.