Microbial additives affect silage quality and ruminal dry matter degradability of avocado (Persia Americana) pulp silage

Abstract

This study evaluated effects of microbial inoculation on fermentation, aerobic stability and ruminal dry matter (DM) degradation of silage produced from Avocado (Persia Americana) pulp (AP). The AP, 800 g/kg fresh matter (FM) was mixed with 150 g grape pumice (GP)/kg FM and 50 g sugarcane molasses/kg FM. The mixture was treated with 1) no inoculant (control), 2) Emsilage inoculant (EMS), and 3) Sil-All 4x4 W.S. inoculant (SIL). Materials were ensiled in 1.5 L anaerobic jars for 90 days. Triplicate samples were collected on days 0, 3, 7, 10, and 90 for determination of fermentation, nutritive value and aerobic stability. In situ DM degradability was determined using 3 rumen cannulated Holstein cows. Microbial inoculation to AP silage increased lactic acid bacteria population, which subsequently increased residual fermentation substrate and lactic acid content. Terminal pH and volatile fatty acids of the silage were not affected by inoculation. Inoculated silage had less fibre and reduced aerobic stability compared to the control. The AP and its mixture had higher DM soluble fractions compared to the GP which had a higher degradation rate. Potential degradable fraction and extent of degradation were similar for each treatment. The EMS treatment had higher soluble fractions and lower degradation rate than other treatments. Inoculation with SIL improved degradation of the silage compared to other treatments. Thus, microbial inoculation qualifies the AP silage as a potential feed for ruminants.

Keywords: feed, grape pomace, inoculant, oil cake, organic acid