The nutritional composition, fermentation characteristics, in sacco degradation and fungal pathogen dynamics of sugarcane tops ensiled with broiler litter with or without water

The study was conducted to investigate changes in chemical composition, fermentation characteristics, mycotoxin-producing fungi (MPF) and in sacco disappearance of DM in the rumen following ensiling of sugarcane tops (SCT) with broiler litter (BL) with or without water. Chopped SCT and BL were hand-mixed (DM basis) to obtain 3 kg mixtures of 0, 15, 30, 45 and 60% BL. The mixtures were ensiled with or without water, for 45 days in polyethylene bags. In addition to chemical analyses, fermentation characteristics, disappearance of DM from nylon bags and mycotoxin-producing fungi (MPF) were determined. Ensiling decreased (P<0.001) the CP (78 versus 91 g/kg DM) and GE (18.8 versus 19.3 MJ/kg OM) contents whilst BL increased (P<0.001) the DM, CP, ash, Ca and P contents of silages. The ensiling by BL interaction was highly significant (P<0.001) for DM, EE and NDF, significant (P<0.01) for CP and ash, but not significant (P>0.05) for GE, Ca and P. Water decreased (P<0.001) the DM content, had no effect (P>0.05) on the GE content but increased (P<0.01) the NDF content of silages. The BL by water interaction was highly significant (P<0.001) for DM and less significant (P<0.05) for CP and GE. Ensiling decreased (P<0.001; 4.3 versus 6.4) whilst BL increased (P<0.001) the pH. The ensiling by BL interaction was significant (P<0.001) for pH but neither the effect of water nor that of water by BL interaction was significant for pH (P>0.05). BL increased (P<0.001) but water decreased (P<0.01) the lactic acid (LA; 61 versus 68 g/kg DM) content of silages. The BL by water interaction was significant (P<0.01) for LA. The differences among treatments for DM loss were highly significant (P<0.001) at the 48 h incubation period (DML48). BL decreased (P<0.05) the DML48 of pre-ensiled mixtures but increased (P<0.05) that of post-ensiled mixtures. The BL by water interaction was significant (P<0.05) for DML48. Ensiling destroyed Fusarium and Rhizopus and reduced the incidence of Scopulariopsis fungi. Aspergillus, Scopulariopsis and Penicillium fungi showed the ability to survive under anaerobic conditions. Water enhanced the destruction of moulds in silage. The incidence of yeasts was directly proportional to BL in silage. Although results indicated that BL is a good protein and mineral source suitable for use in improving the nutritional value of SCT, negative effects on silage quality were observed at BL inclusion rates beyond 45%. It is recommended that 30–45% is the most appropriate inclusion level of BL in sugarcane tops silage.