Abstract: This paper was to research the effect of different proportions of fermented cottonseed meal included in diets on small intestinal mucosa morphology, T lymphocyte cell subset and intestinal microflora in Yellow chicken. Selected 14-day-old healthy broiler 320, were randomly divided into 4 groups, each group four replicates of 20 chickens per replicate. Ⅰ Group was the control group fed with the basal diet, Ⅱ, Ⅲ and Ⅳ groups were added 3%, 6% and 9% fermented cottonseed meal in diets,respectively. The aim was to study the effect of different content of fermented cottonseed meal on the early (14 to 28 days), medium (29 to 45 days), and later (46 to 65 days) periods on small intestinal mucosa morphology, T lymphocyte cell subset of medium and later periods and intestinal microflora of later periods in broilers.The results showed that the early, medium, the height of villus of duodenal of the wholes periods in Ⅲ group were significantly increased respectively by 31.90%,25.17% and 49.41% (P<0.01). The depth of crypt of duodenal in Ⅲ group were significantly reduced by 9.42%,11.31% and 10.83% (P<0.01).The V/C of duodenal in Ⅲ group were significantly increased respectively by 45.65%,41.19% and 67.84% (P<0.01). The height of villus of jejunum of the wholes periods in Ⅲ group were significantly increased respectively by 28.72%,28.38% and 27.61% (P<0.01). The depth of crypt of jejunum in Ⅲ group were significantly reduced by 6.65%(P<0.05),6.18% (P<0.01), 7.37%(P<0.01). The V/C of jejunum in Ⅲ group were significantly increased respectively by 37.84%,36.69% and 37.82% (P<0.01).The height of villus of ileum of the wholes periods in Ⅲ group were significantly increased respectively by 76.64%,40.36% and 67.20% (P<0.01). The depth of crypt of ileum in Ⅲ group were significantly reduced by 4.09%,6.07% and 6.02% (P<0.05).The V/C of ileum in Ⅲ group were significantly increased respectively by 83.79%,49.27% and 78.26% (P<0.01).The CD4⁺/CD8⁺ of broilers in Ⅳ group was significantly increased respectively by 42.86% and 34.95% (P<0.05) in the medium and later periods. With the increasing of the amount of fermentation of cottonseed meal, the number of broilers of the duodenum, jejunum, ileum of lactic acid bacteria increased gradually, excepte the difference of lactic acid bacteria of duodenum and jejunum of Ⅱ group was not significant, the number of the intestines of lactic acid bacteria of rest group increased gradually significantly. The number of the Escherichia coli and Salmonella reduced gradually, excepte the difference of the duodenal segment of Escherichia coli of Ⅱ group and the different of lactic acid bacteria of the duodenum, jejunum, ileum of the intestines. In a word, 6% fermented cottonseed meal in improving the villus heigh of the duodenum, jejunum, ileum, reducing its crypt depth, and improving the V/C was better than 3%, 9% fermented cottonseed meal group, while 9% fermentation cottonseed meal group in improving the CD4⁺/CD8⁺ and the number of lactic acid bacteria and reducing the number of the Escherichia coli and Ssalmonella was better than 3% and 6% fermented cottonseed meal group.

Key words: Yellow chicken; small intestinal mucosa morphology; T lymphocyte cell subset; intestinal microflorain