Methane Production Potential of Fruit and Vegetable Wastes In Vitro

The main aim of this study was to assess the methane production potential and nutritional worth of fruit and vegetable wastes (FVWs) as livestock feed by in-vitro/in-sacco techniques. The selected FVWs [cabbage leaves (CabLs), cauliflower leaves (CauLs), empty pea pods (PPs), sarson saag waste (SSW) and fruit juice waste without peels (FJW)] were rich in protein varying from 14.6% (SSW) to 20% (CabLs); and EE varying between 2.2% (CauLs) to 3.2% (PPs). The SSW had the highest and CauLs had the lowest amount of cell wall components. The net gas production (NGP) was the highest (P<0.01) from FJW followed by pea pods and lowest in CauL. The methane production expressed either as percent in NGP, as ml/100mg DM or as ml/100mg digestible OM at t&frac12; was the highest (P<0.01) in pea pods and lowest in CauLs and CabLs. The digestibility of NDF and true OM in CabLs was comparable with that of FJW, CauLs and peapods, but significantly higher than SSW. The availability of ME was highest from FJW (11.7 MJ/kg DM) followed by that from PPs and lowest was observed in CauLs (7.73 MJ/kg DM). Amongst the FVW evaluated, the total volatile fatty acids (TVFAs) and individual VFA production were observed to be significantly higher from FJW, followed by SSW and CauLs and lowest was from that of pea pods. The acetate: propionate ratio varied significantly from 3.3 (CabLs, SSW and FJW) to 4.05 (CauLs). The digestion kinetics parameters of DM, CP and NDF revealed that the degradation rate (except that of NDF), effective degradability, true digestibility, potential and apparent extent of digestion were observed to be significantly higher in FJW and SSW; and lowest values of these parameters were observed in CabLs. Reverse but significant trend was observed with respect to rumen fill values, which is inversely proportional to potential voluntary DM intake. The results conclusively revealed that amongst the tested FVWs, sarson saag waste and fruit juice waste followed by cauliflower leaves and pea pods have great potential as livestock feed and can serve as alternate feed resources for livestock and can supplement or replace the costly feedstuffs.