Efecto de la aplicación de inóculos microbianos sobre las características fermentativas, estabilidad aeróbica y consumo voluntario de ensilaje de gramíneas tropicales naturalizadas

Abstract

Two experiments were conducted to determine the effects of two different microbial inoculants of homo-fermentative and hetero-fermentative lactic acid-producing bacteria (LAB), on the fermentation characteristics, aerobic stability (AS), and intake by sheep, of native tropical grasses (NTG). Prior to ensiling, NTG were treated or not with the inoculants, applied at 10⁶ cfu/g of fresh material for Commercial Inoculant 1, and 10¹⁰ cfu/g of fresh material for Commercial Inoculant 2. Treatments were applied to weighted portions of NTG, manually mixed, and packed Into PVC laboratory silos. To evaluate fermentation characteristics, silage samples from each treatment were analyzed at seven ensiling periods(0,4,7,14,21,28, and 35days) to determine pH and fermentation products (organic acids and Nhi-N). For AS determination, triplicate silos from each treatment were emptied after 35 d of ensiling, and the silage placed in styrofoam containers lined with plastic bags, and exposed to air during five days. Temperature was monitored every six hours during the five days and pH was determined after 0, 1, 3, and 5 d of aerobic exposure. To determine voluntary intake, NTG were fermented with or without the inoculant of LAB during 35 d In 208 L (55 gallon) capacity plastic bags. For each in vivo trial, six meat-type crossbred sheep were used; three fed each of two experimental diets during five days. The diets had In common 50% tropical grass hay and 50% NTG fermented with or without the LAB and were offered dally on a 3% dry matter basis (DMB) of body weight. The addition of neither of the two inoculants of LAB achieved great improvement ¡n the fermentation characteristics of NTG, which proved acceptable in control silages. In both experiments, silages with and without inoculants were stable during five days under aerobic conditions. There was a positive effect of inoculation with Commercial Inoculant 1 on voluntary intake in the first experiment, but not with Commercial Inoculant 2 in the second trial.