Investigating the effects of substituting different levels of biuret instead urea on nutrient intake, growth performance, nutrient digestibility, blood metabolites and feeding behavior of Afshari fattening lambs

Articles in Press

Document Type : Research Paper

Authors

1 Ph.D. Student, Department of Animal Science, Faculty of Agriculture, Lorestan University

2 Department of Animal Science, Lorestan University

3 Professor, Department of Animal Science, Faculty of Agriculture, Lorestan University

4 Department of Animal Processing, Animal Science Research Institute of Iran (ASRI), Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran

Abstract

The aim of the present study was to investigate the effects of substituting different levels of biuret instead of urea on nutrient intake, growth performance, nutrient digestibility, blood metabolites, and feeding behavior of fattening lambs. Twenty-eight Afshari fattening male lambs with average age of 135±15 days and average live weight of 34±0.13 kg were used in a completely randomized design with 4 experimental treatments and 7 replications. The experimental diets included a control treatment (1.2% urea on dty matter (DM) basis) and the inclusion of levels of 0.54, 1.08, and 1.61% biuret based on dietary DM instead of urea. First, the experimental diets were incubated in an in vitro test to determine the concentration of ammonia-N, and then the diets were fed to the experimental animals for 70 days. Using biuret in the diet did not affect nutrients intake including DM, organic matter (OM), crude protein and neutral detergent fiber (NDF) and feeding behavior traits compared to the control treatment (P<0.05). With increasing the level of biuret in the diet, daily weight gain, total weight gain and feed conversion ratio improved linearly compared to the control treatment (P<0.05). As the level of biuret increaed in the diet, the digestibility of NDF increased linearly compared to the urea-containing treatment (P<0.05), although OM digestibility was not affected by the experimental diets (P<0.05). With increasing the amount of dietary biuret, the concentration of blood total protein increased linearly, but the concentration of blood urea nitrogen decreased linearly compared to the treatment containing urea (P<0.05). Overall, the results of the present study showed that the use of biuret compared to urea in the diet caused a decrease in ammonia-N content in the rumen and improved growth performance and feed conversion ratio. Therefore, the use of biuret up to 1.61% of dietary DM is recommended in fattening lambs.

Main Subjects

Animal Production Research

Articles in Press, Accepted Manuscript
Available Online from 19 May 2025

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