PSXIV-14 Evaluation of 21 fungal strains as pretreatment of corn stover: chemical composition and in vitro digestibility

Abstract

Abstract Agricultural by-products such as corn stover (CS) are abundantly available in many countries; however, its high content of neutral detergent fiber (NDF) and lignin (L) and low protein content, causes low digestibility and nutrient availability for ruminants. The production of edible fungi could improve the digestibility of the CS because fungi can break down the cross-links between cell wall components. The aim of the study was to evaluate the effect of the invaded CS-based substrate used in the production of 21 white rot fungi of the species: Auricularia sp (Auri), Ganoderma sp (Gano), Hericium sp (Heri), Lentinula edodes (LC, L5, L9, L15, L21), Pleurotus eryngii (Pe-PQ, Pe-MB), Pleurotus djamour (Pd-Pro, Pd-UTMR) and Pleurotus ostreatus (Po-IAP, Po-Psma, Po-P14, Po-POS, Po-IE202, Po-JP, Po-P35, Po-P38, Po-Sfco) on crude protein (CP), NDF and L content and in vitro dry matter digestibility (IVDMD). The variables were analyzed in a completely randomized design with the MIXED procedure of SAS and the comparison of the means was made with the Tukey analysis. For CP, a significant increase (P < 0.05) was observed from 10% (Pe-MB) to 41% (LC) in comparison with the substrate without inoculation (C). There was a decrease (P < 0.05) of NDF from 2% (LC) to 10% (Pd-PRO) against C. Fungal treated CS had no effect on L (P < 0.05) as compared to C. Treatments increased (P < 0.05) IVDMD from 3% (L15) up to 36% (Po-POS) for all fungal strains, except for Pe-PQ and Po-Sfco in comparison with C. There was a positive correlation (r2=0.21, P < 0.05) between CP and IVDMD. An equation was obtained to predict IVDMD [IVDMD=0.40578 + 358.38(%ADF)–358.02(%NDF)+358.17(%HEM)–0.3211(%DM), R2=0.32 (P < 0.05)]. In conclusion the mycelial invasion of white rot fungi on a CS-based substrate, increased CP content, decreased NDF and improved IVDMD, making it a viable option to increase the digestibility of CS.