Study On The True Metabolizable Energy In Ducks With Bionic Digestion System

In this study, artificial small intestinal fluids were prepared with enzyme reagents based on the activities of digestiva enzymes, ion concentrations and pH value of the small intestinal juices in Beijing Ducks. A pepsin-artificial small intestinal fluid in vitro digestion method using bionic digestion system was established according to the difference between in vitro digestion and biological method.The first part was to study the biological characteristics and its variation factors of Beijing duck intestine with the purpose of providing parameters for the prepatation of artificial intestine. In experiment 1, a completely random design was adapted to study the effects of dietary type on the composition of jejunal juice in Beijing ducks. In experiment 2, a completely random design of two kinds of storage temperature and three storage periods was conducted to study the appropriate in vitro storage conditions for jejunal juice. Results showed that dietary type significantly affected the activities of digestive enzymes,ion concentrations and pH values of intestinal juices (P<0.05). Storage temperature significantly affected the pH (P<0.05), but did't influence (P>0.05) the digestive enzyme activity. Storage time significantly affected the pH of jejunal juices from these two treatments, and the activities of trypsin and amylase of jejunal juice in ducks fed corn–- mixed protein meal diet (P<0.05). In conclusion, dietary type is one of the important factors affecting the biological characters of jejunal juice in Beijing ducks, and effects of storage conditions on the biological characters of small intestinal juice could be dependent on the dietary type.The second part studied the suitable hydrolysis time and the tested accuracy of pepsin-artificial intestinal fluids in the monogastric animal digestive system. The results showed that the optimum time of the simulated gastric digestion period was 4h, and the optimum time of small intestinal digestion simulation period was 15h. The relative average deviation and coefficient of variation of dry matter digestibility as well as digestible energy tested by the bionic method were all below 2%.The third part was conducted to compare the precision of metabolizable energy using digegtion bionic method with the bioligical method in 19 cottonseed meal samples. Results showed that there was no significantly difference (P>0.05) between the average DEBM (9.73±0.21MJ/kg) and TME (9.84±0.64MJ/kg ) of 15 cottenseed samples. However the average DEBM (8.52±0.11MJ/kg) of the rest 4 samples was significantly lower (P<0.05) compared with the TME (9.76±0.82MJ/kg). The coefficient of variation of DEBM in the 19 samples were all less than 5%, however there were only 6 samples with the coefficient variation of TME below 5%. In conclusion, it was acceptable for DEBM to estimate TME in cottonseed samples.The precision and distinguish ability of DEBM were better than TME.