Evaluation of the nutritional value of Iranian melon (Cucumis melo cv. Khatooni) wastes before and after ensiling in sheep feeding

There is little information on the nutritive value of ensiled Iranian melon (Cucumis melo cv. Khatooni) wastes (IMW) for sheep feeding; therefore, the nutritional value of IMW was investigated before and after ensiling. Treatments were 1) Fresh IMW as control [FIMW], 2) Ensiled IMW [EIMW], 3) Ensiled IMW with 1% grape vinegar [EIMW+1% GV], and 4) Ensiled IMW with 2% grape vinegar [EIMW+2% GV]. The IMW samples (after harvesting the ripe fruits) were ensiled in the polyethylene tubes for 60 days. Ensiling IMW increased the contents of dry matter (DM) and crude protein (CP). The concentration of CP was also increased (P<0.05) in the silages supplemented with GV. However, neutral and acid detergent fiber (NDF and ADF, respectively) and ash contents were unchanged among treatments. The addition of grape vinegar to the silage increased the concentrations of lactic and acetic acids and decreased NH3-N compared to control silage (P<0.05). However, total volatile fatty acids (TVFA) and pH of silages were not significantly affected by the treatments. The highest values of gas production parameters (gas12, 24, 48, 72 h and bgas), true dry matter (TDMD) and organic matter degradability (TOMD) were observed in FIMW (P<0.05). Ensiling IMW without additive, decreased TDMD and TOMD, whereas treating silages with GV increased its digestibility (P<0.05). The highest partitioning factor (PF) and efficiency of microbial mass yield (EMMY) were detected in EIMW+2% GV (P<0.05). Generally, it can be concluded that IMW can be used as a potential forage source in sheep feeding either as fresh or ensiled by-product. However, because of the high moisture content of IMW, ensiling with 2% GV could improve the nutritional value and fermentation parameters.