Effect of level of alimentation on visceral organ mass and the morphology and Na+, K+ adenosinetriphosphatase activity of intestinal mucosa in lambs.

Changes in ovine visceral organ mass and small intestinal mucosa morphology and metabolism due to short-term and prolonged modifications in level of alimentation were studied. Thirty-six lambs were fed for 21 d at either 100 or 50% ad libitum levels of intake. For the next 5 d, lambs either remained on the same intake levels or were switched from 100 or 50% or from 50 to 100% ad libitum intake levels and were subsequently slaughtered. Levels of alimentation the last 5 d before slaughter had a significant effect on weights of the large intestine, small intestine, stomach complex and liver, while only the weight of the liver was affected by 21-d adaptation period. Weights of the heart, lungs, carcass and visceral fat were not affected by level of alimentation. Villus height and mucosal mass at a constant intestinal tissue weight were modified by level of alimentation 5 d before slaughter but static to the previous 21-d nutritional plane. Activity of Na+, K+ ATPase of jejunal mucosa was not influenced by level of alimentation 5 d before slaughter, but was influenced by 21-d adapted level of alimentation. Results from this study are interpreted to indicate that weights of the liver and alimentary tract and small intestinal mucosa development are highly sensitive to changes in level of alimentation.