Effect of solid-state fermentation using Aureobasidium pullulans and Mucor circinelloides on camelina meal proximate composition and digestibility

Abstract: Several studies have shown that microbial fermentation improves the nutritional value of the oilseed meals by reducing the antinutritional factors (ANFs) present in the oilseed meals. The generally regarded as safe (GRAS) microbes have been used successfully submerged and solid-state fermentation of various substrates including canola, soybean, carinata meals. In this study, cold pressed camelina meal (CPCM) with high levels ANFs (glucosinolates, phytic acid, fibers, oligosaccharides) was subjected to the solid-state fermentation for 7 days by using Mucor circinelloides and Aureobasidium pullulans. At the end of fermentation, fermented meal was dried at 60°C for 3 days, finely ground to determine the proximate composition. Experimental plan also included the uninoculated control. The crude protein content of the raw CPCM (34.6%) did not change except for the A. pullulans fermented meal (36.7%). Similarly, there was significant reduction in the phytic acid content of Mucor fermented CPCM while there was no change in the control and A. pullulans fermented CPCM as compared to the raw CPCM. There was no change in the amino acid profile and crude fiber content of raw, control and fermented CPCM. The performance of the fermented CPCM meal was determined by conducting a fish digestibility trial where 30% reference diet was replaced with either raw, control or fermented CPCM meals. Chromic oxide was included as an inert marker at 0.75% of the diets. Diets were fed to rainbow trout (300-500g) for seven days before stripping feces. Four replicates were used for each diet. Feces were freeze-dried for 36h and then oven dried at 60⁰C for 24h to ensure that they were thoroughly dry. Composition data of the processed diets, and feces plus chromic oxide in diets and feces is pending analysis.