Nutritional composition and aerobic stability of wheat and corn silages stored under different environmental conditions

Abstract

We aimed to evaluate nutritional quality, fermentation profile, aerobic stability, and dry matter losses in corn (Zea mays) and wheat (Triticum aestivum 'BRS Umbu') silages. Treatments included uninoculated and inoculated (Lactobacillus plantarum and Pediococcus acidilactici, 1.0 × 105 UFC g-1) wheat silage, corn silage from a conventional hybrid and a transgenic hybrid. Nutritional quality and fermentation profile variables were tested in a completely randomized design. Means were compared using Tukey’s test at 5% significance. An aerobic stability trial was conducted in a factorial design with two silages (wheat × inoculated wheat; conventional hybrid corn × transgenic hybrid corn) and two temperatures (ambient temperature × controlled temperature at 24°C). Data were submitted to ANOVA and means were analyzed by the F test at 5% probability. Inoculation of wheat silage increased dry matter, organic matter, and total carbohydrates, but reduced crude protein by a dilution effect. Regarding the fermentation profile, inoculation reduced acetic acid and butyric acid content, whereas it increased propionic acid in wheat silage. Bt corn hybrid silage showed higher dry matter and lower neutral detergent fiber, whereas transgenic corn silage showed lower content of acetic acid, propionic acid, alcohol, and ammonia. Conversely, Bt hybrid silage showed higher butyric acid. Transgenic corn silage showed higher temperature than the conventional hybrid silage during aerobic exposure. Inoculated wheat silage experienced larger deterioration and dry matter losses during the aerobic stability trial. Temperature control worsened aerobic stability in all treatments, increasing dry matter losses and heating.