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Subchronic toxicity test for two thermotolerant filamentous fungi used for single cell protein production
Abstract:
Safety evaluations of two thermotolerant filamentous fungi, Cephalosporium eichhorniae 152 (C. 152) and Rhizopus chinensis 180 (R. 180), grown on a sugar-salts medium were carried out through feeding the biomases to rats at 20% or 40% dietary levels for 90 days. There was a control group fed soybean meal. Weight gain and feed consumption for rats fed 20% C. 152 were equal to those for the control animals, but were depressed in the other three groups, especially the rats fed R. 180. All animals appeared normal and healthy except that transient alopecia was found for a short duration in the fungi-treated rats in the initial period. The cause of this lesion is not clear. At the end of the feeding trial, clinical determinations of constituents in blood and urine samples were conducted. The animals were autopsied and weights for four organs were taken. Histopathological examinations for 26 different tissues were carried out. Mild changes were found in both C. 152 and R. 180-treated rats but most of the these were not considered to be related to treatment.
Insights
Safety evaluations of Cephalosporium eichhorniae 152 (C. 152) and Rhizopus chinensis 180 (R. 180) in rats showed minimal adverse effects. Mild changes were observed, but most were not treatment-related, indicating potential safety for these fungi.
Area of Science:
- Mycology
- Toxicology
- Food Science
Background:
- Thermotolerant filamentous fungi offer potential as food sources.
- Assessing the safety of fungal biomass for consumption is crucial.
Purpose of the Study:
- To evaluate the safety of Cephalosporium eichhorniae 152 (C. 152) and Rhizopus chinensis 180 (R. 180) biomass in a 90-day rat feeding study.
Main Methods:
- Rats were fed diets containing 20% or 40% fungal biomass (C. 152 or R. 180) for 90 days.
- Control group received soybean meal.
- Evaluations included weight gain, feed consumption, clinical blood/urine analyses, organ weights, and histopathology of 26 tissues.
Main Results:
- Weight gain and feed consumption were comparable to controls for rats fed 20% C. 152.
- Depressed weight gain was observed in other groups, particularly with R. 180.
- Transient alopecia occurred initially in fungi-treated rats; cause undetermined.
- Mild histopathological changes were noted but mostly unrelated to fungal treatment.
Conclusions:
- Fungal biomass from C. 152 and R. 180 showed a generally good safety profile in rats over 90 days.
- Further investigation may be needed for R. 180 at higher dietary levels.
- The transient alopecia requires further study to determine its cause and significance.