Ammonia and urea distribution and urease activity in the gastrointestinal tract of rabbits (Oryctolagus and Sylvilagus)

Effect of fermentable carbohydrates on volatile fatty acids, ammonia and mineral absorption in the rat caecum

“…In addition to VFA production, urea is transferred from the blood to the digestive contents, particularly in the large bowel, and ammonia is absorbed (Vince et at., 1973 ;Knutson et al, 1977). The effect of carbohydrates reaching the large bowel has been studied with lactulose mainly in humans (Vince, Killingley and Wrong, 1978) and with lactose in rats (Demigné and R6m6sy, 1979 (Bergmeyer, 1974).…”

Urea cycling and ammonia absorption in vivo in the digestive tract of the rat

“…Urea nitrogen transfer and ammonia production have been studied in the caecum of various rodents, especially rabbits (Hoover and Heitmann, 1975 ;Knutson et al, 1977) as a part of the nitrogen used in bacterial synthesis is re-utilized after coprophagy. The ammonia produced is partly reabsorbed in the blood, and reaches the liver where it must be completely detoxified into urea.…”

Effect of D‐mannitol on nitrogen retention, fiber digestibility and digesta transit time in adult rabbits

“…Some urea‐N enters the cecum from the blood (Knutson et al . ), and is transferred to ammonia by bacterial ureolytic activity (Forsythe & Parker ). The ammonia‐N transferred from blood urea is used for bacterial N synthesis (Demigné & Rémésy ; Younes et al .…”

“…In rabbits, fermentable sugars can be used as a source of energy for cecal bacterial growth (Davies & Davies 2003). Some urea-N enters the cecum from the blood (Knutson et al 1977), and is transferred to ammonia by bacterial ureolytic activity (Forsythe & Parker 1985). The ammonia-N transferred from blood urea is used for bacterial N synthesis (Demigné & Rémésy 1979;Younes et al 1995).…”