Fermentative parameters and aerobic stability of orange peel silage with pelleted citrus pulp

Abstract

This study evaluated the effects of pelleted citrus pulp (PCP) added to orange peel on fermentative parameters and aerobic stability of orange peel silages. The treatments were based on different levels of PCP: 0 (control), 10% PCP, 20% PCP, and 30% PCP calculated according to the weight of orange peel (w/w), with five experimental silos per treatment stored for 60 days. Chemical composition, fermentative parameters, microbial population, and dry matter (DM) losses were performed in silages after opening the experimental silos. Furthermore, aerobic stability was evaluated for 12 days. Silages with 10 and 20% PCP presented suitable levels of DM, 226 and 302 g kg−1, respectively, and probably adequate water activity that benefited the lactic acid fermentation, but it jeopardized their aerobic stabilities. The inclusion of 10% PCP did not reduce the effluent loss compared with the control silages. Yet, 30% PCP silage showed the lowest effluent loss (93%), in contrast to the low lactic acid content (35 g kg−1) and short aerobic stability (49 h). Control silages remained stable for a longer period (115 h), but showed greater loss of N as NH3 , and higher losses of DM through gas (354 g kg−1) and effluents (114 g kg−1). In short, we highlighted 20% PCP silage because of its high lactic acid bacteria (6.3 cfu g−1), high lactic acid:acetic acid ratio (1.41), low nitrogen degradation as NH3 , and reduced gas (67%) and effluent (80%) productions. With the highest lactic acid (66.42 g kg−1), these well-preserved silages showed a more intense aerobic degradation, starting after 42h. The inclusion of PCP to orange peel improves the fermentation process probably due to the decrease of water activity, but decreases the aerobic stability of the silage as well