| This study was investigated to the mainly digestive enzyme activities, pH, ion concentration in duodenal, jejunal, ileal fluid and digesta characteristic along the small intestine of layer-type cockerel. The results would provide a reference for the in vitro simulation digestion of intestine in poultry.In this experiment, the variation of digesta flow in duodenum, jejunum and ileum of layer-type cockerel fitted with T-shaped Cannula was investigated to study the biological character of intestinal digesta. A3x6factorial completely random design with3days digesta collection period and6points of dayly sampling was adapted. Fifteen birds in3groups were selected from35duodenal,32jejunal and33ileal cannulated cockerels, respectively, and each group was allotted into5replicates with3birds per replicate. The digesta was collected for1h out of every4h on d31,34and37of the experiment. The flow of intestinal digesta, digesta dry matter, intestinal fluid, and total protein were determined. The results showed that no significant difference was found between the body weight on day1before cannulation operation and that on day25after operation (P>0.05). The percent of cannulated cockerels in good health was about80%on day120after operation. There was no significant difference of survival ratio in3groups cannulated cockerels (P>0.05). The flow per hour of digesta, digesta dry matter and intestinal fluid were reduced from duodenum to ileum. Collection time in day cycle significantly affected the flow of digesta, digesta dry matter, intestinal fluid and total protein (P<0.05).The significant differences were found in average flow of digesta, digesta dry matter and intestinal fluid of duodenum, flow of digesta and intestinal fluid of jejunum, as well as total protein of jejunal fluid on different collection day (P<0.05). In conclusion, the cannulated cockerels can be recovered after25days and survive at least4months. On ad libitum diet and natural light, the flow of digesta, digesta dry matter, intestinal fluid and total protein are more in daytime than night, and fluctuate on different collection day.Experiment2was conducted to study the effects of dietary crude protein to metabolizable energy ratios (CMR) on the composition of intestinal fluid in layer-type cockerel, and the intestinal digesta characteristic of birds fed on maize-soybean meal. In trial Ⅰ, six treatments consisted of combinations of14.42g/MJ,11.89g/MJ of CMR and3intestinal segments was adapted. Six groups of fifteen cannulated cockerels each were selected, and each group was allotted into5replicates with3birds per replicate. Mainly digestive enzyme activities, pH and ion concentration in duodenal, jejunal and ileal fluid were determined. In trial Ⅱ, Three groups of20duodenal cannulated birds,20jejunal cannulated birds and20ileal birds were selected, and each group was allotted into5replicates with4birds per replicate. The maize-soybean basal diet was available ad libitum. The results showed that the activity of lipase in duodenal fluid was significantly higher than jejunal and ileal fluid (P<0.05), and the activities of amylase, trypsin, chymotrypsin in jejunal fluid were very significantly higher than those of duodenal and ileal fluid (P<0.01). The ion concentration of the intestinal fluid from different position showed that the Na+concentration and K+concentration was separately reached the lowest in duodenal and jejunal fluid, however, the Mg2+concentration and Ca2+concentration were the highest in jejunal fluid (P<0.01). The Cl-concentration was decreased significantly along the intestine, but pH was increased (5.06-8.51). Apparent energy digestibility of the diet was-1.33%,49.67%,55.33%in the duodenum, jejunum and ileum, respectively (P<0.01). High CMR diet significantly increased Ca2+concentration and the activities of lipase, trypsin, chymotrypsin, but pH was decreased(P<0.05). In conclusion, the activities of amylase, trypsin, chymotrypsin in jejunal fluid were the highest and diet digestion occurred mainly in jejunum. |
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