Effect of slow release urea in sheep feed on nitrogen balance

• Autor(a) principal: Geron, Luiz Juliano Valério
• Data de Publicação: 2018
• Outros Autores: Garcia, Jocilaine, Aguiar, Sílvia Cristina de, Costa, Fabiana Gomes da, Silva, Ana Paula da, Sousa Neto, Eurico Lucas, Carvalho, Joilma Toniolo Honório de, Roberto, Lucas Silva, Coelho, Kallynka Samara Martins, Santos, Ilda Souza
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Semina. Ciências Agrárias (Online)
• DOI: 10.5433/1679-0359.2018v39n2p683
• Texto Completo: https://ojs.uel.br/revistas/uel/index.php/semagrarias/article/view/27295
• topic: Excretion; Faces; Intake; Non-protein nitrogen; Urine.; Consumo; Excreção; Fezes; Nitrogênio não proteico; Urina.

The aim of this study was to evaluate the effect of inclusion of 0.0%, 0.4%, 0.8%, and 1.2% slow release urea (SRU) in sheep feed on nitrogen balance (intake, fecal and urinary excretion, nitrogen absorbed and retained and/or nitrogen balance). Four sheep with an average body weight (BW) of 30.8 ± 1.7 kg were distributed using a Latin square experimental design. Sheep were allocated in metabolic cages and received two meals a day. The data were subjected to analysis of variance and differences were tested using a regression equation with a 5% probability. The inclusion of 0.0%, 0.4%, 0.8%, and 1.2% SRU in sheep diets did not change (p > 0.05) nitrogen intake (NI), with an average value of 20.49 g animal day-1 and 1.57 g (kg0.75)-1. The inclusion of 0.0%, 0.4%, 0.8%, and 1.2% SRU in sheep diets did not affect (p > 0.05) fecal nitrogen (FN) in g (kg0.75)-1, with an average value of 0.65 g (kg0.75)-1. However, the inclusion of SRU changed (p < 0.05) the FN, expressed as g animal day-1, and % BW, in a quadratic manner. The lowest FN excretion was 7.63 g animal day-1 and 36.41% NI, and it was obtained at inclusion levels of 0.82% and 0.66% SRU, respectively. The inclusion of 0.0%, 0.4%, 0.8%, and 1.2% SRU in sheep diets had a quadratic effect (p < 0.05) in urinary nitrogen (UN), expressed as g animal day-1, g (kg0.75)-1, and % of NI. The minimum values calculated with the equations for UN were 0.86 g animal day-1, 0.06 g (kg0.75)-1, and 0.28% NI for SRU inclusion levels of 0.79%, 0.76%, and 0.71%, respectively. The inclusion of 0.0%, 0.4%, 0.8%, and 1.2% SRU in sheep diets did not change (p > 0.05) the NB expressed as g animal day-1 (10.86) and g (kg0.75)-1 (0.82). However, the NB expressed as % NI or in relation to the NI responded in a quadratic manner (p < 0.05) to the inclusion of different levels of SRU in sheep food. The maximum value for NB was 59.68% NI and it was obtained at 0.68% SRU. Thus, the inclusion of 0.6% to 0.8% slow release urea in sheep diets provides the lowest fecal and urinary nitrogen losses. In addition, these levels provide the best NB values, expressed as a percentage of NI.