Evaluation of collection method and diet effects on apparent digestibility and energy values of swine diets

Authors: LI, YANSHUO - University Of Nebraska; TRAN, HUYEN - University Of Nebraska; BUNDY, JUSTIN - University Of Nebraska; BURKEY, THOMAS - University Of Nebraska; Kerr, Brian; NIELSEN, MERLIN - University Of Nebraska; MILLER, PHILLIP - University Of Nebraska

Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/13/2016
Publication Date: 6/3/2016
Publication URL: https://handle.nal.usda.gov/10113/6571360
Citation: Li, Y., Tran, H., Bundy, J., Burkey, T., Kerr, B.J., Nielsen, M., Miller, P. 2016. Evaluation of collection method and diet effects on apparent digestibility and energy values of swine diets. Journal of Animal Science. 94:2415-2424.

Interpretive Summary: In animal nutrient metabolism and feed ingredient evaluation research, accurate collection feces and urine is critical for determining energy or nutrient digestibility. There is however, no universally accepted method of collecting feces or urine across research locations. Data from these experiments demonstrate that there were no major differences in digestibility estimates for dry matter or gross energy between the use of a marker-to-marker or a day method of feces and urine collection. This information provides scientists conducting animal nutrient metabolism studies an understand that there are several acceptable methods for collecting feces and urine in metabolism studies, both of which result in similar estimates of energy or nutrient digestibility.

Technical Abstract: Two experiments were conducted to investigate the effects of collection method and diet type on digestibility coefficients. In Exp. 1, 24 barrows were fed either a corn-soybean meal diet (CSBM) or CSBM with 20% dried distillers grains with solubles (DDGS). In Exp. 2, the effects of basal diet and collection method on determination of DDGS digestibility were studied using 24 barrows. Basal diets were either a CSBM (basal-1) or barley-canola meal diet (BCM; basal-2) in combination with or without 20% DDGS replacement, respectively (CSBM-DDGS and BCM-DDGS). In both experiments, fecal collections were based on exact timing (DY) or marker-to-marker (MM) collection methods. Diets contained 0.5% of titanium dioxide (TiO2) for estimating digestibility using the index marker approach (IM). The apparent total tract digestibility (ATTD) of DM and GE were lower (P < 0.05) in CSBM-DDGS vs. CSBM diet in Exp. 1, but were not different (P > 0.10) in Exp. 2. All the estimates of BCM-based diets were consistently lower (P < 0.05) than CSBM-based diets. In Exp. 1, digestibility coefficients determined by DY and MM were not different (P > 0.10) from each other; whereas, those estimates were lower (P < 0.05) using the IM vs. total collection (TC; DY and MM) approaches. In Exp. 2, interactions (P < 0.05) were observed between diet type and method for dietary digestibility coefficients. Digestibility and energy values estimated by DY and MM were not different (P > 0.10) in pigs fed CSBM-based diets and BCM-DDGS; whereas, those estimates were greater (P < 0.05) using DY vs. MM in pigs fed the BCM. There were no interactions (P > 0.10) between basal diet and method for estimating DDGS digestibility. The ATTD of DM and GE of DDGS using MM were greater (P < 0.05) than IM, and ATTD of N tended to be greater (P < 0.10) using MM vs. IM. All estimates using DY were not different (P > 0.10) from MM or IM, except that DE of DDGS was greater (P < 0.05) using DY vs. IM. Digestibility estimates of DDGS were not affected (P > 0.10) by basal diets. The mean DE and ME (as-fed basis) of DDGS were 3,994 and 3,688, and 3,919 and 3,547 kcal/kg estimated using basal-1 and basal-2 diets, respectively. In conclusion, there were no major differences between DY and MM on determination of digestibility values of a complex diet or DDGS except for the BCM basal diet.