Carcass characteristics, non-carcass components and blood parameters of fattening lambs fed on diets containing amaranth silage substituted for corn silage

Fifty fattening male Moghani lambs (28.5 +/- 1.9 kg) were used to assess the effect of the dietary substitution of amaranth silage (AS) for corn silage (CS) on carcass characteristics, non-carcass components, and blood chemistry parameters. Five iso-energetic and iso-nitrogenous diets were offered to the experimental animals (10 lambs per treatment) for 98 days using a completely randomized design. The lambs individually received diets in which different levels (0.0, 75.0, 150, 225, or 300 g/kg of diet DM) of AS were substituted for CS. The diets were offered ad libitum as total mixed rations twice daily. Weight gain and concentrations of blood chemistry parameters were determined. At the end of the experimental period, the harvest data and carcass characteristics of the lambs were recorded. Dietary replacement of CS by AS improved total gain, carcass weight and carcass cuts including neck, shoulder, brisket, loin and legs (linear (L), P< 0.05), but reduced fat-tail weight. Carcass length, and loin-eye width, depth and area were similar among the dietary treatments. Inclusion of the enhancing levels of AS in the diet increased empty gastrointestinal tract weight (L, P= 0.012). The weights of carcass components including lean, bone and fat were increased with the incorporation of AS in the diet (P< 0.05). The dietary substitution of AS for CS had no effect on the offal parts and blood chemistry parameters (P> 0.05), except for triglycerides concentration. Overall, using AS in the diet of fattening Moghani lambs up to 300 g/kg of dietary DM improved total gain and carcass weight without any effect on lean to fat ratio and animal health. (C) 2013 Elsevier B.V. All rights reserved.