Project Number: 3625-31000-003-10
Project Type: Reimbursable

Start Date: May 01, 2008
End Date: May 01, 2009

Objective:
The objectives of the proposed research are to: 1) determine the ability of an in vitro organic dry digestibility technique (Noblet and Peyraud, 2006), to predict digestible energy content of various corn co-products in finishing pigs; 2) determine the apparent digestible and metabolizable energy content of these feedstuffs in finishing pigs; and 3) compare these two methods of digestible energy determination.

Approach:
Ten different corn milling co-products will be selected based on: availability, practicality of use, and range of nutrient composition, to assess the ability of an in vitro organic matter digestibility technique to estimate digestible energy concentration as determined in finishing pigs weighing approximately 90 kg. In addition, apparent metabolizable energy concentration will be determined in these same feedstuffs and compared to estimation based upon chemical composition. The in vitro organic matter digestibility method will be adapted from Noblet and Peyraun (2006). In general, this method consists of digesting 0.5 g of sample with pepsin for 2 hours, followed by digestion with pancreatin solution for 4 hours, followed by digestion with Viscozyme for 18 hours. The solution is then filtered and dried to determine organic matter digestibility. This value, combined with analysis of the feedstuff for ash, starch, ether extract, or acid detergent fiber, is then used with prediction equations to estimate digestible energy content. Furthermore, equations published by Noblet et al. (1994) will be used to calculate metabolizable and net energy content of each feedstuff. For the determination of apparent digestible and metabolizable energy concentration, gilts weighing approximately 90 kg will be randomly assigned to one of 6 experimental diets in each block of ingredients. Within each block a basal diet will be formulated to satisfy nutrient requirements as suggested by the NRC (1998). As such, each block will consist of a basal diet and 5 experimental diets generated by blending the basal diet with an equal quantity of the co-product to be tested. Pigs will be fed twice daily at approximately 2.5% of their body weight with water provided ad libitum. Pigs will be housed individually in metabolism crates designed for total, but separate collection of feces and urine. Pigs will be allowed to adapt to the experimental diet for a minimum of 7 days, followed by a 4-day total period. Energy balance will be conducted by typical nutrient balance procedures. There will be eight replications for each co-product. Block 1 co-products will include HP-DDG, DDGS-12% fat, DDGS-6% fat, DDG-3% fat, and dried solubles-without fat, in addition to the basal diet. Block 2 co-products to include Gluetnol, Energia, corn bran, corn germ meal-without oil, and corn gluten meal, in addition to the basal diet. The difference method (Adeola, 2001) will be used to subtract out the energy attributed by the basal diet from the diet containing the test ingredient. All data will be analyzed using the GLM procedures of SAS with the effects of dietary treatment on the dependent variables of digestible and metabolizable energy.