Effect of slow release urea in sheep feed on nitrogen balance

Luiz Juliano Valério Geron, Jocilaine Garcia, Sílvia Cristina de Aguiar, Fabiana Gomes da Costa, Ana Paula da Silva, Eurico Lucas Sousa Neto, Joilma Toniolo Honório de Carvalho, Lucas Silva Roberto, Kallynka Samara Martins Coelho, Ilda Souza Santos

Abstract


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.

Keywords


Excretion; Faces; Intake; Non-protein nitrogen; Urine.

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DOI: http://dx.doi.org/10.5433/1679-0359.2018v39n2p683

Semina: Ciênc. Agrár.
Londrina - PR
E-ISSN 1679-0359
DOI: 10.5433/1679-0359
E-mail: semina.agrarias@uel.br
Este obra está licenciado com uma Licença Creative Commons Atribuição-NãoComercial 4.0 Internacional