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Protein Structures among Bio-Ethanol Co-Products and Its Relationships with Ruminal and Intestinal Availability of Protein in Dairy Cattle
Department of Animal and Poultry Science, College of Agriculture and Bio-Resources, University of Saskatchewan, Saskatoon, SK S7N 5A8, Canada
Faculty of Agriculture, Lorestan University, PO Box 465, Khorramabad, Iran
Grasslands Research Centre, AgResearch Ltd., Tennent Drive, Private Bag 11008, Palmerston North 4442, New Zealand
Department of Animal Science, Tianjin Agricultural University, 22 Jinjin Road, Xiqing District, Tianjin 300384, China
* Author to whom correspondence should be addressed.
Received: 10 July 2013; in revised form: 27 July 2013 / Accepted: 5 August 2013 / Published: 15 August 2013
Abstract: The objectives of this study were to reveal molecular structures of protein among different types of the dried distillers grains with solubles (100% wheat DDGS (WDDGS); DDGS blend1 (BDDGS1, corn to wheat ratio 30:70%); DDGS blend2 (BDDGS2, corn to wheat ratio 50:50 percent)) and different batches within DDGS type using diffuse reflectance infrared Fourier transform spectroscopy (DRIFT). Compared with BDDGS1 and BDDGS2, wheat DDGS had higher (p < 0.05) peak area intensities of protein amide I and II and amide I to II intensity ratio. Increasing the corn to wheat ratio form 30:70 to 50:50 in the blend DDGS did not affect amide I and II area intensities and their ratio. Amide I to II peak intensity ratio differed (p < 0.05) among the different batches within WDDGS and BDDGS1. Compared with both blend DDGS types, WDDGS had higher α-helix and β-sheet ratio (p < 0.05), while α-helix to β-sheet ratio was similar among the three DDGS types. The α-helix to β-sheet ratio differed significantly among batches within WDDGS. Principal component analysis (PCA) revealed that protein molecular structures in WDDGS differed from those of BDDGS1 and between different batches within BDDGS1 and BDDGS2. The α-helix to β-sheet ratios of protein in all DDGS types had an influence on availability of protein at the ruminal level as well as at the intestinal level. The α-helix to β-sheet ratio was positively correlated to rumen undegraded protein (r = 0.41, p < 0.05) and unavailable protein (PC; r = 0.59, p < 0.05).
Keywords: protein molecular structures; α-helix to β-sheet ratio; dried distillers grains with soluble (DDGS); intestinal digestibility
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Azarfar, A.; Jonker, A.; Yu, P. Protein Structures among Bio-Ethanol Co-Products and Its Relationships with Ruminal and Intestinal Availability of Protein in Dairy Cattle. Int. J. Mol. Sci. 2013, 14, 16802-16816.
Azarfar A, Jonker A, Yu P. Protein Structures among Bio-Ethanol Co-Products and Its Relationships with Ruminal and Intestinal Availability of Protein in Dairy Cattle. International Journal of Molecular Sciences. 2013; 14(8):16802-16816.
Azarfar, Arash; Jonker, Arjan; Yu, Peiqiang. 2013. "Protein Structures among Bio-Ethanol Co-Products and Its Relationships with Ruminal and Intestinal Availability of Protein in Dairy Cattle." Int. J. Mol. Sci. 14, no. 8: 16802-16816.