Gallo Antonio, Giuberti Gianluca, Bruschi Sara, Fortunati Paola, Masoero Francesco
Feed and Food Science and Nutrition Institute, Faculty of Agricultural, Food and Environmental Sciences, Università Cattolica del Sacro Cuore, 29122, Piacenza, Italy.
J Sci Food Agric. 2016 Mar 30;96(5):1686-96. doi: 10.1002/jsfa.7272. Epub 2015 Jun 24.
To investigate corn silage fermentative quality, a principal factor analysis was carried out on a database consisting of 196 corn silages sampled from the core, lateral and apical parts of silo feed-out face and characterised by 36 variables. Eleven principal factor components (PCs) were retained and interpreted. Two PCs were related to chemical and digestibility variables; four PCs were characterised by end-products associated with clostridia, heterolactic, homolactic or aerobic fermentations; two PCs were associated with mycotoxins produced by Penicillium roqueforti or by Aspergillus fumigatus and Fusarium spp., while three PCs explained ensiling procedures adopted to store corn silages.
Lower (P < 0.05) yeast or mould counts and greater (P < 0.05) aerobic stability were measured in core than in peripheral samples. Excluding PCs related to ensiling procedures, other PCs were able to predict microbiological counts, aerobic stability or biogenic amine content as verified by multiple linear regression analysis. Based on these results, several corn silage quality index calculations were computed by using a summative equation approach in which different PCs as well as diverse relative weights multiplying each PCs were combined. To compute definitive index calculation, only PCs explaining clostridia, heterolactic and homolactic fermentations were used with relative weights of 30%, 50% and 20%.
The new proposed fermentative quality index was highly correlated to parameters related to corn silage fermentative quality, such as microbiological counts, aerobic stability or biogenic amines and it properly discriminated well- and poorly preserved forages.
为研究玉米青贮饲料的发酵品质，对一个数据库进行了主成分分析，该数据库包含从青贮饲料出料面的核心、侧面和顶部采集的196份玉米青贮样本，并以36个变量为特征。保留并解释了11个主成分（PCs）。两个主成分与化学和消化率变量相关；四个主成分的特征是与梭菌、异型乳酸、同型乳酸或需氧发酵相关的终产物；两个主成分与罗克福特青霉或烟曲霉及镰刀菌属产生的霉菌毒素有关，而三个主成分解释了储存玉米青贮饲料所采用的青贮程序。
与外围样本相比，核心样本中的酵母或霉菌计数较低（P < 0.05），需氧稳定性较高（P < 0.05）。通过多元线性回归分析验证，除了与青贮程序相关的主成分外，其他主成分能够预测微生物计数、需氧稳定性或生物胺含量。基于这些结果，通过使用汇总方程方法计算了几个玉米青贮饲料质量指数，其中将不同的主成分以及乘以每个主成分的不同相对权重进行了组合。为计算最终指数，仅使用解释梭菌、异型乳酸和同型乳酸发酵的主成分，其相对权重分别为30%、50%和20%。
新提出的发酵品质指数与玉米青贮饲料发酵品质相关参数高度相关，如微生物计数、需氧稳定性或生物胺，并且能够很好地区分保存良好和保存不佳的草料。
