Study On Digestion Of Fats In Vitro In Ducks

There was a phenomenon in the single stomach bionics digestive system (SDS-1) developed by State Key Laboratory of Animal Nutrition,which is that the process of fat digestive may be slower in vitro digestive, in this research,the first step is to resolve a suitable method determining the metabolizable energy of fats in ducks, and determine the metabolizable energy of the three different mixed grease, on this basis, the speed of digestion of fats in vitro digestive and the Emulsifier’s influence on the speed of that were researched, and the initial proposed method of sped ding up fat disappear from digestive residue, through comparing the didderences of determination value in vitro and in vivo, further testing feasibility of the accelerated bionic digest method of fat digestive rate, provided basis for improvement of Bionic digest method for measuring the metabolizable energy of feed in ducks.The first part was conducted to study the biological method for determining the metabolizable energy of fats in ducks according to the effects of endogenous excreta on the metabolizable energy of fats and the test precision using difference method and digestibility calculation method. Experiment1was to study the difference of true metabolizable energy of dietary fats by difference method and digestibility calculation method in ducks. The true metabolizable energy of fats of4diets with no fat (basal diet, diet4), corn oil (diet1), soybean oil (diet2) and lard (diet3), respectively, were determined. Experiment2was conducted to determine the difference of true metabolizable energy of fats mixed with two diets by digestibility calculation method which was selected according to the experiment1. A two factorial randomized design with2treatments of diets (corn-soybean meal diet and corn starch diet) and3treatments of dietary fats (corn oil:soybean oil=5.22:1, corn oil:soybean oil=1.90:1, corn oil:soybean oil:lard=14.28:3.50:4) was adopted. The true metabolizable energy of fats of diet5～10was determined. The results showed as follows:the coefficient of variation was11.39%in true metabolizable energy of dietary fats from endogenous fecal energy in difference method, and that was1.43%from endogenous fat in digestibility calculation method. The average coefficient of variation, and maximum, minimum and range in all replicates of the true metabolizable energy of3fats were22.39%,41.70MJ/kg,24.77MJ/kg,16.94MJ/kg by difference method, and4.44%,36.23MJ/kg,33.03MJ/kg,3.19MJ/kg by digestibility calculation method, respectively. In digestibility calculation method, there were no significant differences in the true metabolizable energy of mixed fat combined with corn oil and soybean oil under two dietary treatments (P>0.05), but there were significant differences in that of mixed fat combined with corn oil, soybean oil and lard (P<0.05). It is shown that digestibility calculation method has less interference from endogenous loss and higher repeatability than difference method for the determination of metabolizable energy of dietary fats in ducks, but the metabolizable energy of dietary fats determined by digestibility calculation method is also affected by other dietary nutrients.The second part was conducted to compare the digestible of fats between controls group and digestive juices group, compare the digestible of fats under the conditions of different emulsifiers and digestive juices group and simulation digest feed remnants flushed by Ethanol. Results showed that there was significantly difference (P<0.05) between controls group (4.27±0.23) and digestive juices group (48.71±1.25).the average digestible of fats under the conditions of different emulsifiers was significantly lower (P<0.05) compared with that of fats of the digestive juices group.however the average digestible of fats of the digestive juices group was significantly lower (P<0.05) than the group of simulation digest feed remnants flushed by EthanolThe third part was conducted to compare the precision of metabolizable energy using digegtion bionic method with the bioligical method in3Corn-soybean samples. Results showed that there was no significantly difference (P<0.05) between the average DEBM (14.67±0.06MJ/kg) and AME (14.60±0.06MJ/kg) of3Corn-soybean samples. The coefficient of variation of DEBM in the3samples were all less than1%, however there were not samples with the coefficient variation of AME below1%. In conclusion, it was acceptable for DEBM to estimate AME in Corn-soybean samples.The precision and distinguish ability of DEBM were better than AME.