Abstract: This study was aimed to research the effect of intestinal membrane protein and fermented soybean meal replacing fish meal on the immunity and digestive tract development of weaned piglets.A total of 180 weaned piglets,half male and half female,Duroc×Landrace×Yorkshire at 28 days old with body weight (8.0 ± 0.5)kg,were randomly divided into 3 treatments with 6 replicates of 10 piglets per pen.The diet of control group contained 17.0% soybean meal + 6.0% fish meal,the other two diets contained 16.6% soybean meal + 4.0% fermented soybean meal + 4.0% imported or domestic intestinal membrane protein.The pre-test period lasted for 3 days and the trial period lasted for 14 days.The results showed that compared with the control group,the indexes of spleen,mandibular lymph and the serum content of ALB in imported intestinal membrane group were significantly increased by 43.53%,49.18% and 16.20%,respectively (P<0.05),and in domestic membrane group,the index of spleen was significantly increased by 41.77%,and the serum content of complement C3 was significantly decreased by 16.22% (P<0.05);there were no significant differences in the indexes of thymus,inguinal lymph,iliac lymph,popliteal lymph,superficial cervical lymph,and the levels of serum TP,BUN,IgA,IgG and NO among all groups (P>0.05).Compared with the control group,there was no significant difference in the weight of stomach and duodenum in imported intestinal membrane group (P>0.05),but the weight of stomach and duodenum in domestic intestinal membrane group were significantly decreased by 19.68% and 48.55%,respectively (P<0.05).The length of duodenum in imported intestinal membrane group was significantly increased (P<0.05),while in domestic intestinal membrane group was significantly decreased (P<0.05).The length of jejunum and the weight of ileum in imported intestinal membrane group and domestic intestinal membrane group were significantly decreased (P<0.05),the villus height of ileum in domestic intestinal membrane group was significantly decreased (P<0.05).There were no significant differences in the weight of liver and jejunum, the length of ileum and the villus height and crypt depth of duodenum and jejunum among all groups (P>0.05).It was concluded that imported or domestic intestinal membrane protein and fermented soybean meal replacing fish meal could not affect major immunity organ index,serum items and intestine morphology of weaned piglets,but there were significantly decreased in the weights of stomach and duodenum in domestic membrane protein group.

Key words: intestinal membrane protein; fermented soybean meal; weaned piglet; immunity; digestive tract development