Use of the mobile nylon bag technique to determine the digestible energy content of traditional and non-traditional feeds for swine

The following experiment was conducted using the mobile nylon bag technique (MNBT) to determine dry matter and energy digestibility in traditional feeds as well as non-traditional feeds in order to calculate digestible energy (DE) values for use in ration formulation programmes. A total of 22 ingredients were tested in this experiment including the traditional cereal grains barley, corn, oats and wheat, as well as secondary cereal grains such as normal and low viscosity rye, low lignin and high fat oat groats, wheat heavies and # 1 wheat screenings and a new bread wheat designated as CDC Teal. Three legumes (lupines, peas and dehydrated alfalfa), three varieties of canary seed (CDC Maria, dehulled CDC Maria and Keet), and raw and micronized canola seed were tested as protein sources. Finally, three oilseed meals obtained from the Chinese feed industry (Chinese rapeseed meal, Chinese cottonseed meal and extruded full-fat soybean meal) were also included. After simulating gastric digestion the nylon bags were inserted into the duodenum of five barrows through simple duodenal T-cannulae. Eight bags were administered to each pig daily. Ten nylon bags were prepared for each feed with two bags being inserted into each of the five barrows. A total of 220 bags were inserted over a 7-day period. The overall results of this experiment indicate that the MNBT has great potential for use in determining the digestible energy content of swine feeds. For the most part, values obtained in the present experiment compared favourably with previously published values. Four feedstuffs produced digestible energy values that differed by greater than 5% from previously reported values. However, variation in chemical content provided a reasonable explanation for these discrepancies. The MNBT has several advantages compared with conventional digestibility methods in that many feeds can be tested in a relatively short duration of time with significantly fewer animals being used, only small amounts of feed are required and the test allows for energy measurements in feedstuffs that would not normally be fed to pigs as a single ingredient. Additional research on a wider variety of feedstuffs should be conducted to confirm the potential of the MNBT as a tool to accurately determine DE values for swine.