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ARS Home » Midwest Area » Ames, Iowa » National Laboratory for Agriculture and The Environment » Agroecosystems Management Research » Research » Publications at this Location » Publication #333681
Title: Disappearance and appearance of an indigestible marker in feces from growing pigs as affected by pre- and post-diet composition

Author
item JACOBS, BRANDY - Iowa State University
item PATIENCE, JOHN - Iowa State University
item LINDEMANN, MERLIN - University Of Kentucky
item STALDER, KEN - Iowa State University
item Kerr, Brian

Submitted to: Journal of Animal Science and Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/20/2017
Publication Date: 4/1/2017
Citation: Jacobs, B.M., Patience, J.F., Lindemann, M.D., Stalder, K.J., Kerr, B.J. 2017. Disappearance and appearance of an indigestible marker in feces from growing pigs as affected by pre- and post-diet composition. Journal of Animal Science and Biotechnology. 8:1-9. doi: 10.1186/540104-017-0161-9.

Interpretive Summary: Evaluation of nutrient digestion in growing pigs is critical in feedstuff evaluation. During the conduct of this type of research, inert dietary markers are often fed to indirectly measure nutrient digestion. However, when pigs are used more than once during the course of digestion studies, the potential confounding effect of a marker lingering in the gastrointestinal tract after a diet change may affect subsequent digesta analysis and bias the results. Data from this study indicates that as the digestibility of the diet increases, it took progressively longer for a fecal marker to be excreted, which is critical to know when pigs are utilized for multiple times during a digestibility experiment. Research results described in this report provides scientists and swine producers information on how to use dietary markers during digestibility studies more correctly in order to obtain digestibility data that is not affected by previous dietary treatments.

Technical Abstract: Indigestible markers are commonly utilized in digestion studies, but the disappearance or appearance of a marker in feces can be affected by diet composition or particle size, or by the feed intake or the BW of an animal. There is limited information relative to how long after removal or introduction of a marker in the feed such that fecal concentration has fallen to zero or risen to a stabilized concentration, respectively, when combined with a change in diet composition. Therefore, the objectives of this study were to determine the impact of pre- and post- diet composition on marker (Cr) disappearance and marker (Ti) appearance in growing pigs fed 3 diets differing in NDF content. Crossbred barrows (n = 72) with an initial BW of 59.2 kg were individually penned and randomly assigned to 1 of 3 Phase-1 (P1) dietary treatments. Pigs were fed for 14 d and then randomly reassigned within P1 dietary treatments to 1 of 3 Phase-2 (P2) dietary treatments, and fed an additional 14 d, resulting in 9 treatment groups of 8 pigs each. Treatments consisted of a dehulled, degermed corn-soybean meal diet containing 4.5% NDF, a corn-soybean meal diet containing 9.1% NDF, and a corn-soybean meal-distillers dried grains with solubles diet containing 15.4% NDF. Phase-1 diets utilized chromic oxide (Cr2O3) and P2 diets utilized titanium dioxide (TiO2) to prevent the potential contamination of the marker in the digestive tract in P1 with that of P2 in order to compare marker disappearance and appearance relative to a pre- and post- diet change. For each pig and each day during P1 and P2, fresh fecal samples were collected and subsequently analyzed for either Cr or Ti. The data indicated that when diet digestibility increased (i.e., decreasing dietary NDF), it took progressively longer for fecal Cr to be excreted or fecal Ti to be maximized (P < 0.01). These effects were not, however, independent of the previous diet as indicated by the interaction between P1 and P2 diets on fecal marker concentrations (P < 0.01). The results from the present study show that as dietary NDF increased from P1 to P2, it took less time for fecal Cr to fall or fecal Ti to be maximized, than if NDF decreased from P1 to P2 where it took longer for fecal Cr to fall or fecal Ti to be maximized. With the wide range in excretion times reported in the literature and improved laboratory methods for elemental detection, the data suggests that caution must be taken in considering dietary fiber concentrations so that no previous dietary marker addition remains in the digestive tract or feces such that a small amount of maker is present to confound subsequent experimental results and that marker concentration has stabilized when these samples are taken.