Atuhaire Andrew M, Kabi Fred, Okello Samuel, Mugerwa Swidiq, Ebong Cyprian
National Livestock Resources Research Institute, UG-212 UG76 UG TR.TR., Tororo, Uganda.
Department of Livestock and Industrial Resources, School of Veterinary Medicine and Animal Resources, College of Veterinary Medicine, Animal Resources and Bio-security (CoVAB), Makerere University, UG-102 UG37 UG.KM.KM, Kampala, Uganda.
Anim Nutr. 2016 Dec;2(4):361-369. doi: 10.1016/j.aninu.2016.08.009. Epub 2016 Aug 25.
The greatest limitation to utilization of maize stover by ruminants as a feed is the high concentration of lignin, which limits fibre digestibility. However, ruminants can effectively utilize maize stover if its nutritive value is improved using white rot fungal species. This study was designed to determine optimal bio-physical conditions for mycelial growth and select the most ideal fungal species and pre-treatment options for improving nutritive value of maize stover. Four popular edible fungal species (viz. and ) were subjected to varying temperatures, pH levels, hydrogen peroxide (HO) concentration and illumination to establish the extent of mycelial growth rate. Inclusion of HO was used to determine optimal levels for preservation and prevention of contamination from other indigenous microbiota. Effects of pre-treatment options on chemical composition and nutritive value of maize stover were also examined. Mycelial growth rate of species on potato dextrose agar (PDA) varied ( < 0.05) with temperature, pH level and HO concentration following a quadratic trend. Optimal temperature, pH and HO concentration for mycelial growth on PDA were 25 °C, 5 and 0.01 mL/L, respectively. Under the different bio-physical conditions, had the highest mycelia density and growth rate. Chemical composition of solid-state fermented maize stover differed ( < 0.05) among the species. Maize stover fermented with had the highest crude protein (CP) of 86.6 g/kg DM, dry matter digestibility (IVDMD) of 731 g/kg DM, organic matter digestibility (IVOMD) of 670.4 g/kg DM and metabolizable energy (ME) of 10.0 MJ/kg DM but with the lowest lignin (sa) of 50 g/kg DM. At 25 °C, had the highest mycelial growth rate on PDA and highest lignin (sa) breakdown in the maize stover substrate. It was, therefore, selected as the most ideal fungal species for improving nutritive value of maize stover. Pre-treatment of maize stover with and molasses under anaerobic condition for 7 days before inoculation with resulted into a substrate with the highest ( < 0.05) CP (96.6 g/kg DM), IVDMD (752.3 g/kg DM), IVOMD (687.2 g/kg DM) and ME (10.2 MJ/kg DM). However, neutral detergent fiber exclusive of residual ash (NDFom) and lignin (sa) fractions decreased ( < 0.05) as a result of subjecting maize stover to pre-treatment with and molasses prior to fermentation with Therefore, pre-treatment of maize stover with and molasses for 7 days prior to fermentation with for 14 days in darkness at 25 °C offered the greatest potential for breaking the lignin barrier.
反刍动物利用玉米秸秆作为饲料的最大限制在于木质素浓度过高，这限制了纤维的消化率。然而，如果使用白腐真菌来提高玉米秸秆的营养价值，反刍动物就能有效地利用它。本研究旨在确定菌丝体生长的最佳生物物理条件，并选择最理想的真菌种类和预处理方法来提高玉米秸秆的营养价值。对四种常见的可食用真菌（即……）进行不同温度、pH值、过氧化氢（H₂O₂）浓度和光照处理，以确定菌丝体生长速率的范围。加入H₂O₂用于确定保存和防止其他本土微生物污染的最佳水平。还研究了预处理方法对玉米秸秆化学成分和营养价值的影响。在马铃薯葡萄糖琼脂（PDA）上，不同真菌种类的菌丝体生长速率随温度、pH值和H₂O₂浓度呈二次趋势变化（P < 0.05）。在PDA上菌丝体生长的最佳温度、pH值和H₂O₂浓度分别为25℃、5和0.01 mL/L。在不同的生物物理条件下，……的菌丝体密度和生长速率最高。固态发酵玉米秸秆的化学成分在不同真菌种类间存在差异（P < 0.05）。用……发酵的玉米秸秆粗蛋白（CP）最高，为86.6 g/kg干物质，体外干物质消化率（IVDMD）为731 g/kg干物质，体外有机物消化率（IVOMD）为670.4 g/kg干物质，代谢能（ME）为10.0 MJ/kg干物质，但木质素（sa）含量最低，为50 g/kg干物质。在25℃时，……在PDA上的菌丝体生长速率最高，且在玉米秸秆底物中木质素（sa）分解最多。因此，它被选为提高玉米秸秆营养价值的最理想真菌种类。在接种……之前，将玉米秸秆与……和糖蜜在厌氧条件下预处理7天，得到的底物粗蛋白（CP）最高（P < 0.05），为96.6 g/kg干物质，IVDMD为752.3 g/kg干物质，IVOMD为687.2 g/kg干物质，ME为10.2 MJ/kg干物质。然而，由于在与……发酵之前对玉米秸秆进行了……和糖蜜预处理，不包括残留灰分的中性洗涤纤维（NDFom）和木质素（sa）组分含量降低（P < 0.05）。因此，在25℃黑暗条件下，先用……和糖蜜对玉米秸秆预处理7天，再用……发酵14天，最有潜力打破木质素屏障。
