Utilização de ureia associada a fontes de carboidratos na alimentação de caprinos

• Autor(a) principal: GALVIS, Olga Ximena Aguilar
• Data de Publicação: 2018
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UFRPE
• dARK ID: ark:/57462/0013000009j4d
• Texto Completo: http://www.tede2.ufrpe.br:8080/tede2/handle/tede2/8113
• topic: Nutrição animal; Caprino; Ureia; Carboidrato; CIENCIAS AGRARIAS::ZOOTECNIA

The objective of this study was to evaluate different carbohydrates sources associated with urea on intake, apparent digestibility of nutrients, productive and physiological response in goats. Thirty-one castrated males without a defined race and initial average weight of 19.8 ± 3.1 kg were randomly assigned to one of four treatments in a complete randomized design with the initial weight as a covariate. The treatments were: 1. corn + soybean meal, 2. corn + urea, 3. cassava meal (Manihot esculenta crantz) + urea and 4. cactus (Nopalea cochenillifera) + urea. All treatments had Tifton 85 (Cynodon spp) hay as roughage source (581.3 g kg -1 of DM), mineral salt mixture and ad libitum water access. The experiment lasted 120 days (30 days of adaptation and 90 days of measurements). The animals fed with cactus + urea presented lower ingestion of dry matter (497.5 g DM d-1, P < 0.05), which promoted lower intake of nutrients and metabolizable energy in comparison to diets with corn and cassava meal (743.6 g DM d-1). Crude protein intake was similar for treatments with corn (+ soybean or + urea (127.7 g d-1) and differed from cassava meal + urea and cactus+ urea (84.6 g d-1, P < 0.05). Apparent neutral detergent fiber corrected for ash and protein (NDFap) intake was lower with cactus + urea (292.8 g d-1, P < 0.05), however, when it was expressed in relation to live weigh was similar among different sources of carbohydrates (12.4 g d-1, P > 0.05). Apparent digestibility of DM (656.8 g kg-1), organic matter (675.9 g kg-1), NDFap (530.9 g kg-1), and non-fibrous carbohydrates (831.7 g kg-1), were similar among the sources of carbohydrates associated with urea (P < 0.05). The time spent for feeding (265.5 min dia-1), rumination (447.4 min dia-1) and idle (727.4 min dia-1) were similar among carbohydrates sources. Blood glucose concentration was lower for animals fed with cactus + urea, and lower concentrations of triglycerides and cholesterol were observed in animals fed with cassava meal. Retention of nitrogen (5.27 g d-1) and microbial protein synthesis (22 g d-1) was similar for all treatments. Corn + soybean meal had higher final body weight (29.3 kg FBW), daily average gain (104.0 g d-1 AG), empty body weight (22.9 kg EBW) compared with cassava diet or cactus + urea (25.2 kg and 20.7 kg FBW, 18.9 e 15.2 Kg EBW, 73.1 and 21.4 g d-1 AG, respectively P > 0.05). Animals fed with cassava + urea showed similarity in variables response to corn + urea and differ from cactus + urea. Cactus + urea reduced commercial yield compared with corn (+ soybean meal or + urea) (39.2% vs43.5% , P <0.05). The carcass compactness and leg muscle indexes, muscle: fat and muscle: bone ratio were similar in animals fed with cassava and corn diets (+ soybean meal + urea) and superior compared with cactus + urea (P <0.05). The pH of the carcass at 0h (6.85) and 24h (5.5) after slaughter, the proportion of commercial cuts in the carcass, the chemical composition in Semimembranosus muscle, physical-chemical characteristics except shear force were similar among carbohydrate sources associated with urea (P > 0.05). The results suggested that despite the lower weight of the carcass, meat characteristics and quality for animals fed with cassava meal + urea were similar to those fed corn + soybean meal, indicating that cassava meal + urea could substitute corn and soybean meal in tropical regions due to availability and cost. The replacement of corn by cactus associated with high levels of urea (30 g kg MS-1) decreased nutrient consumption and, therefore performance, yield and carcass characteristics.