| Two hundred and sixteen YangZhou goslings of 4-10 weeks were used as experimental animals, which were allocated at random to 6 groups of thirty-six each. The ryegrass, alfalfa and wheat middlings contents in treatments were 14%, 16%, 18%, 20%, 22% and 24% separately. The trial compared the effects of different dietary on performance, the concentration of T3 , T4 and GH, chemical digestion, change of intestinal morphology, the absorption and utilization of different nutrition. The effect of different diet on chime evacuation according to indicator Cr2O3 was also studied. The results indicated that:1. During the experimental period, there was no significant difference on the body weight between six groups before 4 week-old(p>0.05). With the increasing day, the difference was obvious slowly, 18% content in the dietary can promote the growth of goslings. Seen from the different proportions of fiber components, the performance of goslings was stronger when the proportion of NDF and ADF was 2.39 to 2.52. In the growth, the intake nutriment satisfied body weight gain firstly, then fulfill the feather growth. In addition, food intake was confined basically at 6 weeks age, and maintained the tendency to the final experiment. There was no significant difference in slaughter indices between 7 week-old and 10 week-old(p>0.05), but the indices of group 5 and 6 were lower than that of the other groups.2. The gizzard with its content remained as the biggest proportion of the gastrointestinal tract in each group, which showed the essentiality of gizzard in digestion. The cecum was less than 8% of the whole tract. The body weight showed correlation with the peptic weight, but not significantly (p>0.05). Different dietary had an effect on cecum length(p<0.05), and there was no difference between other intestines (p>.05). The acidity in gizzard was the highest in the whole tract, which was under 3.00. No significant chyme pH changes were found in duodenum, jejunum and ileum, which changed from 5.5 to 6.5. Age had no effect on chyme pH also except the pH in cecum was influenced by microbial fermentation.3. Different dietary had significant effects on the activities of amylase, protease and lipase (p<0.05). To some extent, 22% and 24% content inhabited the enzyme activities. Theactivities of lipase and protease were almost the highest in jejunum, and that of amylase changed a little in different intestines. It indicated that chemical digestion in chyme was mainly occurred in jejunum. The activity of functional cellulose in the cecum of goslings was small, which was higher at 10 week-old than that of 7 week-old, but not significantly (p>0.05). The concentration of TS and GH of 18% was the highest among six groups. The levels of T4 decreased with the contents of ryegrass, alfalfa and wheat middlings increasing. The body weight showed no significant correlation with T3 , T4 and GH (p>0.05), but T3 had significant correlation with GH (p<0.05).4. The graphs showed broad, leaf-like villi in the duodenum, slender tongue-shaped villi in the jejunum, flat mucosa with significant folds in the cecum. From the graphs no morphological damage to villi in the different intestinal segments was observed. It showed that different dietary had no effect on intestinal morphology. Digestibilities of crude fiber and other nutrients were affected by different dietary. The trial showed that ADS was mainly digested in tract, which in group 2 reached 67.95%. Digestibilities of other nutriments such as crude protein, calcium and phosphor declined with the proportion increased continually, but not significant (p>0.05). The metabolic rate of group 5 and 6 was lower than that of other groups.5. The rapid passage rate and empty of digesta were found in goslings. The empty of chime started after fed diet for 1 hour. Compared with other hours, the empty amount achieved the peak after eating 3~4 hours significantly (p<0.01), then dropped continually. After 10 hours, CriOs can't be detected nearly in fecal. The mode of chyme empty was almost unanimous in...
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