An experimentwas conducted with objective to evaluate the effect of the simple and complexdiets on the morpho-fisiologycal gastrointestinal of young pigs, on their prenursery (7th to 21st day) and nursery phases (21stto 35nd of age). Ninety six crossbreed young pigs (male and females)were allotted to a randomized block design with four treatments, six replicationsand four young pigs for each experimental unit. It were used diets: two simple;a with 16 and the other with 19% the protein (CP) and two complex; a to thebase corn, fish meal, dried milk, corn gluten without the use of soybean meal(CSFS) and the other to the base corn, fish meal, dried milk, soybean meal,without the use of corn gluten (CCFS), both with 19% the CP. The pigs were slaughteredat 14, 21, 28 and 35 days of age. There was reduction of liver absolute andrelative weights and of pancreas relative weights, by using CSFS diet. pH ofthe stomach and intestine contents was not influenced by the diet . The animalsfed simple diet with 16% of CP and complex CSFS showed larger crypt depth (CD)at 21 and 35 days of age, respectively, but did not show effect on the villousheight (VH) and villous:crypt relation (VCR). CD it increased linearly, whileVH and RVC decreased quadraticly until 27th and 30th daysof age, respectively. The simple or complex diet, concerning quality and quantityof ingredients, affected the crypts depth of the small intestine and the auxiliaryorgans weight of the digestion, but did not affect the stomachal pH and intestinecontents of pigs weaned at 21 days of age.
