Author
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GUTIERREZ, NESTOR - Iowa State University |
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SERAO, NICHOLAS - Iowa State University |
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Kerr, Brian |
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ZIJLSTRA, RUUD - University Of Alberta |
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PATIENCE, JOHN - Iowa State University |
Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 8/2/2014 Publication Date: 10/1/2014 Citation: Gutierrez, N., Serao, N., Kerr, B.J., Zijlstra, R., Patience, J. 2014. Relationships among dietary fiber components and the digestibility of energy, dietary fiber, and amino acids, and energy content of 9 corn co-products fed to growing pigs. Journal of Animal Science. 92:4505-4517. Interpretive Summary: The expansion of the ethanol biofuel industry has generated a variety of co-products, which due to availability and price, have become available for use as a potential feedstuff for growing swine. Ethanol companies are always producing different by-product streams from their facilities, with products often having different levels of dietary fiber. It is the understanding of how this fiber affects the energy value to the growing pig which is of utmost importance. This research demonstrated that the caloric value of corn co-products to growing pigs depends largely on its xylose or nonstarch polysaccharides content, compared to other measures of dietary fiber. This information is important for nutritionists at universities, feed companies, and swine production facilities for the determination of the energy value of corn co-products for use in feed formulations, and provides a basis from which to assess its economic value. Technical Abstract: An experiment was conducted to determine the best fitting dietary fiber (DF) assay to predict digestibility of energy, DF, and amnio acids, and energy value of 9 corn co-products: conventional corn bran (CB-NS; 37.0% total non-starch polysaccharides (NSP)), corn bran with solubles (CBS; 17.1% NSP), corn distillers dried grains with solubles (DDGS) conventionally produced (DDGS-CV; 20.4% NSP), reduced oil DDGS (DDGS-RO; 25.0% NSP), uncooked DDGS (DDGS-BPX; 22.0% NSP), high protein distillers dried grains (HP-DDG; 21.9% NSP), dehulled degermed corn (DDC; 1.1% NSP), corn germ meal (CGmM; 44.4% NSP), and corn gluten meal (CGnM; 4.9% NSP). A total of 20 growing pigs (initial body weight: 25.9 ± 2.5 kg) were fitted with a T-cannula in the distal ileum and allotted to 10 dietary treatment groups in a 4-period incomplete block design with 8 observations per treatment. Treatments included a corn-soybean meal based basal diet and 9 diets obtained by mixing 70% of the basal diet with 30% of the test ingredient. The apparent ileal digestibility (AID) of gross energy (GE, from 30.9% in CGmM to 84.4% in DDC) and lysine (from 20.2% in DDC to 65.5% in CGnM) differed (P < 0.01) among ingredients, but the AID of NDF (from 19.5% in CB-NS to 61.0% in CGnM) did not differ (P = 0.11). The apparent total tract digestibility (ATTD) of GE (from 40.3% in CB-NS to 99.6% in DDC) and NDF (from 6.0%in CB-NS to 94.3% in CGnM) were different (P < 0.01) among ingredients. The digestible energy (DE, from 1.83 in CB-NS to 5.04 Mcal DE/kg of DM in CGnM) and metabolizable energy (ME, from 1.80 in CB-NS to 4.37 Mcal ME/kg of DM in CGnM) also differed (P < 0.01). Variance in AID of GE was best explained by the total NSP concentration (R-squared = 0.65).The xylose concentration in NSP best explained variance in ATTD of GE (R-squared = 0.80) and NDF (R-squared = 0.63), and DE (R-squared = 0.66) and ME (R-squared = 0. 71) values. The AID of Lys was not predictable (P > 0.05) from the DF concentration. In conclusion, the variation in digestibility of energy and DF, and the DE and ME values in corn co-products are best explained by the concentration of xylose in NSP or total NSP, without substantial loss of predictability. |