[Effect of volatile fatty acid concentration in the rumen on blood flow in the mesenteric vessels of sheep].

The studies were performed on sheep with chronic rumen fistulae and implanted electromagnetic recorders of blood flow in the anterior mesenteric vein and the anterior mesenteric artery. The animals were fed the diet consisting of sugar beet, urea and mineral salts (diet I) or sugar beet and mineral salts (diet II--nitrogen deficient). The diet caused an increase of blood flow in the mesenteric artery and the mesenteric vein: this increase reached the highest level after 2 hours since the application of the diet. There was noted a positive correlation between the changes of blood flow in the mesenteric vessels and the volatile fatty acid concentration in the rumen. The composition of the diet, differing by a protein level, did not influence significantly the differences in blood flow in the mesenteric vessels. It was suggested that an increase of blood flow in the mesenteric vessels was caused by fermentation of carbohydrates in proventriculi, and hence an increased concentration of VFA in the content attaining the duodenum, stimulation of chemoreceptors in the rumen mucosa and increased activity of cholinergic system in internal organs of the abdominal cavity.