| The objective of this study was to assess the effect of dietary crude fiber (CF) level on the intestinal morphology and growth of growing rabbits. A total of120healthy New Zealand rabbits (49d of age) were randomly assigned to four groups (30rabbits per group), and fed with dietary CF at various level of9%(A),11%(B),13%(C), and15%(D) for three weeks. The average daily gain, health status and intestinal mucosal morphology (villus height, crypt depth and villus height to crypt depth ratio) were investigated. The results showed that the levels of CF in diet could significant effect on the average daily gain, feed efficiency (P<0.05), which showed dose-dependent response from9%to13%. Feeding with13%of CF, rabbits have the greater average daily gain and feed efficiency and lower diarrhea rate. Compared with C group (CF=13%), feeding with9%of CF significant reduce the average daily gain and feed efficiency, and with the diarrhea rate up to33.33%. Meanwhile, feeding with15%of CF decreased the average daily gain and feed efficiency, but there was no significant difference between13%and15%of CF. The highest of average daily feed intake and feed costs were found in15%of CF. Histopathological analysis showed that the low-fiber diet (CF=9%) induced rabbit intestinal inflammation, especially the occurrence of the ileum and colon inflammation. The inflammatory cell infiltrated in intestinal lamina propria and submucosa connective tissue mass and muscular. The intestine mucosal morphology analysis showed that compared with13%CF, fed9%CF diet significant reduced the intestinal villus height and villus height to crypt depth ratio, whereas increased crypt depth. There was no significant difference between13%and15%of CF for the intestine mucosal morphology. In conclusion, this study ponts to feed13%dietary CF can improve the growth in rabbits, but the low crude fiber level induced enteritis which reduce the production performance of the rabbits, and higher crude fiber level increased feed costs. |
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