Chemical, nutritive, fermentation profile and gas production of citrus pulp silages, alone or combined with maize silage

Abstract

Quality attributes of citrus pulp silages that were ensiled alone and combined with maize silage were determined. Fresh samples of lemon, orange and tangerine pulps, maize plants and their combinations were fermented in glass jars for 90 days at about 20 - 25 °C. Treatments included i) 100% maize silage as control (MS); ii) 100% lemon pulp silage (LPS); iii) 100% orange pulp silage (OPS); iv) 100% tangerine pulp silage (TPS); v) 50% LPS and 50% maize silage (LPS + MS); vi) 50% OPS and 50% MS; and vii) 50% TPS and 50% maize silage (TPS + MS). The pH differed among treatment groups. The highest and lowest pH values were recorded for MS group and the OPS + MS group, respectively (3.84 vs. 3.51). The highest dry matter (DM), crude fibre (CF), neutral detergent fibre (NDF), acid detergent fibre (ADF) and hemicellulose (HEM) were observed for MS (P <0.01). Citrus pulp silages alone had significantly greater total digestible nutrients (TDN), organic matter (OM) and non-fibre carbohydrate (NFC) values than MS and the combined silages (P <0.01). Maize silage had higher lactic acid (LA) (101.2 g/kg DM) and acetic acid (AA) (49.3 g/kg DM) concentrations than the citrus groups (P <0.05). In vitro gas production (TG), methane (CH₄), metabolizable energy (ME) and organic matter digestibility (OMD) of the silages were similar (P >0.05). Thus, citrus pulps can be ensiled in spite of their moisture content. However, to increased DM and nutrient content, the citrus pulps should be ensiled with 50% maize.

Keywords: fermentation metabolites, methane production, organic matter digestibility