Zhou Yiqin, Drouin Pascal, Lafrenière Carole
University of Quebec in Abitibi-Temiscamingue, 445, boulevard de l'Universite, Rouyn-Noranda, Quebec, J9X 5E4, Canada.
Lallemand Specialities Inc., Milwaukee, WI 53218, USA.
Asian-Australas J Anim Sci. 2019 Feb 14;32(10):1528-1539. doi: 10.5713/ajas.18.0792. Print 2019 Oct.
To evaluate the effects on microbial diversity and biochemical parameters of gradually increasing temperatures, from 5 to 25 °C on corn silage which was previously fermented at ambient or low temperature.
Whole-plant corn silage was fermented in vacuum bag mini-silos at either 10 or 20 °C for two months and stored at 5 °C for two months. The mini-silos were then subjected to additional incubation from 5 to 25 °C in 5 °C increments. Bacterial and fungal diversity was assessed by PCR-DGGE profiling and biochemical analysis from mini-silos collected at each temperature.
A temperature of 10 °C during fermentation restricted silage fermentation compared to fermentation temperature of 20 °C. As storage temperature increased from 5 to 25 °C, little changes occurred in silages fermented at 20 °C, in terms of most biochemical parameters as well as bacterial and fungal populations. However, a fairly high number of enterobacteria and yeasts (4-5 log10 CFU g FM-1) were detected at 15 °C and above. PCR-DGGE profile showed that Candida humilis predominated the fungi flora. For silage fermented at 10 °C, no significant changes were observed in most silage characteristics when temperature was increased from 5 to 20 °C. However, above 20 °C, silage fermentation resumed as observed from the significantly increased number of LAB colonies, acetic acid content, and the rapid decline in pH and WSC concentration. DGGE results showed that Lactobacillus buchneri started to dominate the bacterial flora as temperature increased from 20 to 25 °C.
Temperature during fermentation as well as temperature during storage modulates microorganism population development and fermentation patterns. Silage fermented at 20 °C indicated that these silages should have lower aerobic stability at opening because of better survival of yeasts and enterobacteria.
评估将先前在环境温度或低温下发酵的玉米青贮饲料温度从5℃逐渐升高至25℃对微生物多样性和生化参数的影响。
全株玉米青贮饲料在真空袋小型青贮窖中于10℃或20℃发酵两个月，然后在5℃储存两个月。随后将小型青贮窖在5℃至25℃范围内以5℃的增量进行额外培养。通过PCR-DGGE图谱分析以及对每个温度下收集的小型青贮窖进行生化分析来评估细菌和真菌多样性。
与20℃的发酵温度相比，10℃的发酵温度限制了青贮饲料的发酵。随着储存温度从5℃升高至25℃，在20℃发酵的青贮饲料中，就大多数生化参数以及细菌和真菌数量而言，几乎没有变化。然而，在15℃及以上温度下检测到相当数量的肠杆菌和酵母菌（4 - 5 log10 CFU g FM-1）。PCR-DGGE图谱显示，土生假丝酵母在真菌菌群中占主导地位。对于在10℃发酵的青贮饲料，当温度从5℃升高至20℃时，大多数青贮饲料特性未观察到显著变化。然而，在20℃以上，从乳酸菌菌落数量显著增加、乙酸含量以及pH值和水溶性碳水化合物浓度的快速下降可以看出青贮饲料发酵恢复。DGGE结果表明，随着温度从20℃升高至25℃，布氏乳杆菌开始在细菌菌群中占主导地位。
发酵期间的温度以及储存期间的温度调节微生物种群发展和发酵模式。在20℃发酵的青贮饲料表明，由于酵母菌和肠杆菌的更好存活，这些青贮饲料在开封时应具有较低的有氧稳定性。
