In Vitro assessment of the nutritive value of expanded soybean meal for dairy cattle

Eman A Elwakeel,Evan C Titgemeyer,Abdelaziz M Nour,Mohamed Ea Nasser,Zongjia J Cheng

doi:10.1186/2049-1891-3-10

Eman A Elwakeel, Evan C Titgemeyer + Show 3 more

Open Access

https://doi.org/10.1186/2049-1891-3-10

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Abstract

Little information is available about the nutritive value of expanded soybean meal, which is produced by expansion of soybeans prior to solvent extraction of the oil. During processing, expanded soybean meal is subjected to additional heat, which might increase the concentration of ruminally undegraded protein. Processing of soybeans with heat during oil extraction could affect lysine availability by increasing ruminally undegraded protein or by impairing intestinal digestion. Our objective was to compare solvent and expanded soybeans with regard to chemical composition and nutritive value for dairy cattle. Samples of expanded soybean meal (n = 14) and solvent-extracted soybean meal (n = 5) were obtained from People's Republic of China to study effects of the expansion process on nutritive value for dairy cattle. Solvent-extracted soybean meal (n = 2) and mechanically extracted (heated) soybean meal (n = 2) from the United States served as references for comparison. Samples were analyzed for crude fat, long-chain fatty acids, crude protein, amino acids, chemically available lysine, in situ ruminal protein degradation, and in vitro intestinal digestibility. No differences were found between solvent-extracted soybean meals from China and expanded soybean meals from China for crude fat, crude protein, amino acids, or chemically available lysine. In situ disappearance of nitrogen, ruminally undegraded protein content, and in vitro intestinal digestion of the ruminally undegraded protein were generally similar between solvent-extracted soybean meals made in China and expanded soybean meals made in China; variation among soybean meals was small. Results indicate that the additional heat from the expansion process was not great enough to affect the nutritive value of soybean meal protein for ruminants. Although expansion may improve the oil extraction process, the impact on the resulting soybean meal is minimal and does not require consideration when formulating ruminant diets.

Highlights

Soybean meal (SBM), a good source of lysine, is widely used as a protein supplement for ruminants [1]
The C-ff-SB and US-meSBM contained a lower proportion of long-chain fatty acids as C16:0 and a higher proportion as C18:1 compared with other SBM products (P < 0.01)
The expansion of SBM prior to fat extraction had no effect on lysine availability in the set of Chinese samples that we evaluated, indicating that heat during the expansion process was not high enough to cause protein damage

Summary

Introduction

Soybean meal (SBM), a good source of lysine, is widely used as a protein supplement for ruminants [1]. Because expanded SBM is subjected to additional heat, it was expected to have greater RUP than solvent-extracted SBM. No research is available on the effect of expanded SBM processing on ruminal protein degradability. Douglas and Parsons [7] evaluated the nutritive value of expanded SBM for poultry by measuring its amino acid (AA) content and the protein solubility and studied the effect of feeding expanded SBM to broiler chicks. They found that the nutritive value of the expanded SBM was similar to standard solvent-extracted SBM

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