Research Finds Mushroom Meal Can Replace Half of Soybean in Shrimp Feeds
- Gauri Khanna
- 12 minutes ago
- 3 min read
Straw mushroom meal can replace up to 50% of soybean meal in whiteleg shrimp diets without harming growth or survival.
Mushroom-derived compounds act as natural prebiotics, boosting beneficial gut bacteria and immune cell counts in shrimp.
The findings point to a practical, lower-cost fungal protein alternative that could reduce aquaculture's reliance on environmentally costly feed ingredients.
A Feed Industry Under Pressure
Aquaculture feeds have a problem. Soybean meal, the dominant plant-based protein in the sector, carries rising costs, land-use concerns, and a volatile supply chain. Fishmeal is environmentally constrained and expensive. Together, these pressures are pushing researchers toward alternative protein sources that can do more than simply replace nitrogen, but also support animal health.
A study published in April 2026 in the Israeli Journal of Aquaculture – Bamidgeh, conducted by researchers at the University of the Philippines Visayas, tested whether straw mushroom meal, derived from locally farmed Volvariella sp., could serve as a functional substitute for soybean meal in the diet of whiteleg shrimp (Litopenaeus vannamei), one of the world's most commercially important aquaculture species.
The 60-day feeding trial formulated five diets in which soybean meal was replaced by mushroom-derived myco-meal at rates of 0%, 25%, 50%, 75%, and 100%. Researchers measured growth, feed efficiency, immune markers, gut microbial populations, and blood glucose as indicators of metabolic health.
What Mushrooms Brought to the Tank
The results were instructive. Growth performance, measured by weight gain, specific growth rate, and feed conversion efficiency, peaked at 50% substitution. A polynomial regression model fitted to the data estimated the optimum inclusion level at approximately 48%, with a strong coefficient of determination (R²=0.96). At this level, shrimp fed the mushroom-containing diet outperformed controls, gaining roughly 20% more weight over the trial period.
The straw mushroom meal contained approximately 27.6% crude protein, along with notable levels of crude fibre, much of it derived from cell wall polysaccharides including beta-glucans and chitin. These compounds are not merely structural; they are biologically active. Beta-glucans are well-established modulators of immune function in crustaceans, capable of stimulating the production of haemocytes, the circulating immune cells that form shrimp's primary defence against pathogens.
Total haemocyte counts rose progressively with increasing mushroom meal inclusion, reaching their highest values at full substitution. Gut counts of lactic acid bacteria, a marker of beneficial microbial activity, also increased with inclusion levels, peaking at 75% substitution before declining slightly at 100%. This pattern suggests that mushroom-derived fibre acts as a prebiotic substrate, a dietary component that selectively feeds beneficial microbes rather than being directly absorbed. Research into functional feed ingredients in aquaculture has increasingly pointed toward exactly this kind of dual nutritional and immunological benefit.
Where the Benefits Plateau
Above 50% substitution, the picture shifted. Weight gain and feed conversion efficiency fell significantly at 75% and 100% replacement, dropping below control values. Blood glucose levels, a recognised marker of metabolic stress in crustaceans, remained stable across the lower inclusion groups but declined at 75% and 100%, suggesting the animals were under metabolic strain.
The researchers propose several explanations. Higher fibre content at elevated inclusion levels may reduce digestibility. Indigestible cell wall fractions could disrupt gut microbial balance at extreme doses, contributing to what is sometimes described as dysbiosis. There is also the possibility of anti-nutritional compounds or changes in feed palatability at higher fungal inclusion rates, though the study did not conduct biochemical assays to confirm these mechanisms directly.
The authors acknowledge this as a limitation. Digestibility trials, amino acid utilisation assays, and molecular immune profiling were not part of the study design, and the functional explanations offered remain interpretations supported by existing literature rather than direct experimental confirmation.
Implications for Sustainable Aquaculture
Despite those caveats, the findings carry genuine practical weight. Straw mushrooms are widely cultivated and relatively inexpensive in the Philippines, making this a commercially plausible ingredient rather than a laboratory curiosity. The ability to replace half of soybean meal in shrimp diets without growth penalties, while simultaneously improving immune markers and gut health, positions fungal-derived feed ingredients as a credible tool for reducing aquaculture's ecological footprint.
Further work is needed, particularly farm-scale trials and economic analyses. But for an industry searching for protein sources that are functional as well as sustainable, this study suggests fungi may have something meaningful to offer.