Utilization of Dietary Fiber from Alfalfa by Growing Swine. II. Volatile Fatty Acid Concentrations in and Disappearance from the Gastrointestinal Tract

TLDR: In this article, the authors studied the production of volatile fatty acids (VFA) in the cecum and colon and their utilization as an energy source in growing and finishing swine fed diets containing 0, 20, 40 or 60% alfalfa meal.

Abstract: Production of volatile fatty acids (VFA) in the cecum and colon and their utilization as an energy source were studied in growing and finishing swine fed diets containing 0, 20, 40 or 60% alfalfa meal. The pH in the cecum and colon had an average value of 5.9, which supports fermentation of lumen contents. Increasing dietary fiber increased the concentration (raM/liter) of VFA in the large intestine; VFA ratio was changed in the cecum (increased acetic: propionic-butyric acids) but not in the colon. VFA disappearing from the lower gastrointestinal tract were equivalent to 79, 147, 227 and 155 kcal per day for pigs fed 0, 20, 40 and 60% alfalfa meal, respectively, at 48 kg body weight and 47 ,231 ,285 and 245 kcal per day, respectively, at 89 kg body weight. VFA produced in the large intestine can therefore provide up to 6.9, 11.3, 12.5 and 12.0% of the energy required for maintenance in the 48 kg pig and 4.8, 11.4, 14.0 and 12.0% in the 89 kg pig fed O, 20, 40 and 60% alfalfa meal, respectively. (