Characterization of peptides in ensiled alfalfa treated with different chemical additives |
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Authors: | Wurong Ding Xusheng Guo Kazuo Ataku |
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Affiliation: | 1. State Key Laboratory of Pastoral Agricultural Ecosystem, College of Pastoral Agriculture Science and Technology, Lanzhou University, , Lanzhou, China;2. State Key Laboratory of Pastoral Agricultural Ecosystem, Institute of Arid Agroecology, School of Life Sciences, Lanzhou University, , Lanzhou, China;3. Department of Dairy Science, Rakuno Gakuen University, , Ebetsu, Japan |
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Abstract: | Effects of different chemical additives on peptide composition in ensiled alfalfa (Medicago sativa L.) were investigated by using gel filtration and determination of N characteristics. The alfalfa silages were prepared untreated (control) or with formic acid, formaldehyde or tannic acid as additives at ensiling. All additives reduced non‐protein N (NPN), ammonia nitrogen (NH3‐N) and amino acid N (AA‐N) in the ensiled forage, and the most effective reduction of NPN and AA‐N was observed in the formaldehyde‐treated silages. Peptides in the control silage were mainly dipeptides to peptides with five amino acid residues. Most peptides in the formic acid‐treated silage contained 4–12 amino acid residues. Although most peptides in the formaldehyde‐treated silages contained 4–6 amino acid residues, there was a considerable proportion of peptides with 7–11 amino acid residues. Tannic acid had little effect on peptide size of ensiled alfalfa extract in which most peptides contained 5–6 amino acid residues. Peptide size in formic acid‐treated alfalfa silage was greater than that in the other treatments. Addition of formic acid and formaldehyde not only increased the peptide concentration in alfalfa silage, but enlarged the peptide size. |
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Keywords: | alfalfa silage chemical additives peptide proteolysis |
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