摘要
This study was carried out to clarify role of ceca in nitrogen nutrition of the chicken. Exp. 1： The effect of cecal ligation on nitrogen utilization and excretion was investigated in chickens fed 5% to 14% protein diet. Irrespective of dietary protein level and different protein sources, the ligation of cecal decreased uric acid excretion and tended to increase nitrogen utilization and balance with the exception of urea-added 10% protein diet. Exp. 2： The effect of cecal ligation on nitrogen utilization and excretion was investigated in conventional and colostomized chickens fed a 5% protein diet or 5% protein diet plus urea. Total nitrogen excretion and uric acid excretion increased by colostomy were depressed by cecal ligation in chickens. Therefore, nitrogen utilization and balance decreased by colostomy were increased by cecal ligation. Urinary nitrogen excretion was significantly decreased by cecal ligation in colostomized chickens, but the cecal ligation did not change fecal nitrogen excretion in chickens fed either diet. Exp. 3： This experiment was carried out to examine the effects of removal of cecal contents on nitrogen utilization, balance and nitrogen excretion in cecally ligated chickens. Total nitrogen excretion was significantly decreased by washing out the cecal contents with saline or antibiotics. The cecal ligation and the removal of cecal contents significantly decreased uric acid excretion in the excreta. There was a highly inverse relationship between microbial counts in the ceca and an excretory amount of uric acid. Exp. 4： In order to examine effects of cecal ligation on microbial activity, microbes were counted and products of microbial fermentation were determined. The ligation of caeca decreased microbial counts, concentrations of acetic, propionic and butyric acids and ammonia concentration of cecal contents. These results suggest that nitrogen metabolism in chickens is affected by possible changes in cecal fermentation caused by preventing the substances from urine and digesta from entering into the ceca.
