Evaluation of Feed Mixtures Amended with Processed Food Waste as Feedstuffs for Finishing Lambs

Abstract

This study was undertaken to evaluate the acceptability, growth performance, and diet digestibility of feed mixtures containing food wastes that were further heat processed for growing-finishing lambs. The first experiment consisted of two feeding trials in which 36 lambs in each trial were fed 1) total mixed rations (TMR) containing extruded feed mixtures that were amended with pulped plate waste (PW) collected from university dining centers or 2) control TMR containing corn, soybean meal, and ground hay in Trial 1 (T1) or soybean hulls in Trial 2 (T2). On a DM basis, the treatment TMR in T1 contained 23.9% PW, and the treatment TMR in T2 contained 24.1% PW. The PW used in this study contained 37.5 ± 9.4% DM, 33.0 ± 8.2% CP, 14.7 ± 5.5% ether extract (EE), and 12.6 ± 5.2% ADF. During T1, lambs fed the control TMR (compared with lambs fed PW) had greater (P<0.05) ADG (299.6 ± 36.3 vs 259.0 ± 54.5 g), less (P<0.05) ADFI (811.1 ± 64.0 vs 2,113.6 ± 748.6 g), and greater (P<0.05) gain:feed (0.37:1 vs 0.24:1 g). During T2, no differences between the control lambs and lambs fed PW were observed in terms of ADG (mean = 231.6 ± 40.9 g), ADFI (mean = 1,766.1 ± 168.0 g), and gain:feed (mean = 0.12:1 g). The second experiment consisted of three digestibility trials (T3, T4, and T5). In T3, 24 wethers were fed an extruded mixture (EF) containing soybean hulls, rolled shelled corn, and 24.5% pulped PW (DM basis). In T4, 28 wethers were fed a dehydrated mixture (DF) containing wheat middlings and ground food waste originating from retail groceries in a 75:25 (DM basis). In T5, 28 wethers were fed an extruded mixture (EFM) containing soybean hulls, rolled corn, and 42.3% pulped PW (DM basis). Apparent DE of EF was determined to be 3.22 ± 1.50 Mcal/kg. Apparent digestibility coefficients of EF were 54.50 ± 2.68% DM, 42.60 ± 4.39% ADF, 60.30 ± 15.68% CP, and 76.23 ± 3.77%EE. Apparent DE of DF was determined to be 3.17 ± 0.24 Mcal/kg. Apparent digestibility coefficients of DF were 64.98 ± 4.76% DM, 74.99 ± 4.91%protein, 15.70 ± 10.84% ADF, and 79.39 ± 5.07 EE. Apparent DE of EFM was determined to be 2.66 ± 0.18 Mcal/kg. The EFM apparent digestibility coefficients were 54.95 ± 4.16% DM, 62.61 ± 7.25% CP, 27.21 ± 7.77% ADF, and 79.78 ± 6.67% EE. This study indicates that amending traditional diets with dehydrated or extruded mixtures containing food waste is a practical processing method for including food wastes in sheep diets. However, acceptability of these diets by individual sheep may vary, and inconsistent growth performance levels and feed efficiencies may occur.