Abstract: The experiment was conducted as 4×4 Latin Square with eight barrows (4 months) fitted with ileum cannulas of T-shape to research the effects of different diets to nutrient apparent digestibility. In an experiment with 4×4 Latin Square design,eight castrates were used to investigate the effects of dietary fiber level and breed on appearance digestibility of nutrients in pigs. Four diets were formulated with equal energy and protein containing four levels of crude fiber were 3%,6%,9% and 12% respectively(dry matter basis).Four breeds of swine were Laiwu,Yorkshire×Laiwu,Yorkshire×Yorkshire×Laiwu and Yorkshire. The experiment results showed that: CF level in low range (3% to 6%),with the crude fiber levels increasing,apparent digestibility of CP was on the rise,but the difference of the digestibility of lysine and methionine was not significant (P>0.05),along with the increase of the content of crude fibre(6% to 12%),the nutrition digestibility decreased significantly (P<0.05).Different varieties of pig exhibitsed extremely significant effect on the nutrition digestibility of dry matters,CP,Ca and phosphorus(P<0.01),but no significant on digestibility of dry matters and CP between Laiwu pig and Yorkshire(P>0.05).There was significant difference between the digestibility of NDF in Laiwu pig(51.44%) and Yorkshire(43.51%).Apparent digestibility of NDF and ADF was significantly decreased as Laiwu pigs origin decrease,and the NDF had been broken down in the small intestine.There were no significant effect on the apparent digestibility of essential amino acid (EAA) among different varieties of pig besides lysine,threonine and isoleucine(P>0.05),Laiwu had a crude feed tolerance feature.

Key words: Laiwu pigs; dietary crude fiber; apparent digestibility; essential amino acid(EAA); NDF