Silagem de cana-de-açúcar aditivada com farelo de mamona detoxificado na dieta de ovinos

Abstract

In the present study, we evaluated the use of sugarcane silage supplemented with increasing levels of detoxified castor meal (0, 5, 10, 15, and 20%) on nutrient intake and digestibility, performance, ingestive behavior, carcass characteristics and commercial cuts, tissue composition, and physicochemical composition. For the study, 40 male NBD (non-bread defined) sheep with a mean initial body weight of 17.4 ± 2.21 kg were used, distributed in an entirely randomized design and aged approximately 150 days. The experimental diet was composed of sugar cane silage added with detoxified castor meal (DCM), soybean meal, ground corn, and mineral mixture, offered in a 60:40 ratio of roughage to concentrate. The diet containing 20% added DCM provided higher (p<0.01) dry matter intake (980.84 g/d), 3.98 (%PV), organic matter (897.24 g/d), ethereal extract (22.33 g/d), total digestible nutrient (760.91 g/d), total carbohydrate (773.11 g/d) and non-fibrous carbohydrate (382, 59 g/d). Linear increase observed for dry matter digestibility (811.2), ethereal extract (896.4), neutral detergent fiber (778.6) and total carbohydrate (821.6) variables for diets composed of 20% DCM added to silage compared to the other experimental treatments. The addition of 20% DCM to sugarcane silage relative to the control diet contributed to the increasing linear effect for final weight (31.39 vs 25.49), total weight gain (13.49 vs 8.90) and average daily gain (207.50 vs 136, 92). Feed rate (kg/ min) of dry matter and neutral detergent fiber reduced (p<0.001; 0.006) with increasing levels of DCM addition to silage. A linear increase (p<0.01) was observed for body weight at slaughter, empty body weight, hot and cold carcass weight and hot carcass yield for treatments with 20% DCM. For the commercial cuts, the addition level of 20% of WFF to silage provided a linear increasing effect for leg (2.35 kg); shoulder (1.28 kg); rib (1.18 kg); topside (0.77 kg) and neck (0.67 kg) and quadratic behavior for loin weight (0.61 kg). For tissues the addition level of 20% favored the linear increase for muscle weight (1.253 kg), bones (0.415 kg) and total fat (0.238 kg) and with no reflection on the yields of the components obtained. In the evaluation of the physicochemical composition, the moisture content and the L* coloration guideline decreased linearly with values of (75.89 vs 77.21; 31.46 vs 34.31, respectively), and for shear force a linear increase (2.36 kgf/cm2) was observed for the 20% level of added DCM. For blood parameters the concentrations of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and serum urea levels decreased linearly (P<0.05), glucose and phosphatase levels increased linearly and magnesium and gamma-glutamyl transferase concentrations showed quadratic behavior. The results indicate that sugarcane silage additivated with detoxified castor meal up to 20% can be used in sheep feed.