Soybean Meal (SBM)
Soybean meal is the solid by-product obtained after oil extraction from soybeans (Glycine max). Due to its high crude protein content, balanced amino acid profile, and good digestibility, SBM is considered the gold standard plant protein in feeds for livestock, poultry, and aquaculture.
Nutritional Composition
Typical solvent-extracted soybean meal contains:
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Crude protein: 44–48%
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Lysine: ~2.8–3.1% (highly valuable for monogastric animals)
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Metabolizable energy: Moderate
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Fiber: Low to moderate
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Fat: <2% (defatted SBM)
Soybean meal is particularly rich in essential amino acids, especially lysine, though it is relatively low in methionine and cysteine.
Anti-Nutritional Factors
Raw soybeans and inadequately processed SBM contain anti-nutritional compounds such as:
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Trypsin inhibitors
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Lectins
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Phytic acid
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Oligosaccharides (raffinose, stachyose)
Proper heat treatment during processing significantly reduces these factors and improves nutrient availability.
Use in Animal Feeding
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Poultry: Primary protein source for broilers and layers
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Swine: Excellent digestibility and growth performance
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Ruminants: Valuable rumen degradable and undegradable protein
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Aquaculture: Widely used as a fishmeal substitute
Fermented Soybean Meal
Recent research has focused on fermented soybean meal (FSBM), produced using microorganisms such as Lactobacillus, Bacillus, Saccharomyces, and Aspergillus. Fermentation:
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Reduces anti-nutritional factors
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Improves protein digestibility
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Produces postbiotics and paraprobiotics
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Enhances gut health and immune response
This aligns well with your ongoing research interests in solid-state fermentation and functional feed ingredients.
Global and Regional Importance
Soybean meal is a cornerstone of the global feed industry. In countries with limited protein feed resources, including Iran, SBM plays a critical role in meeting livestock protein requirements despite reliance on imports.