5TH International Congress on Technology - Engineering & Science - Kuala Lumpur - Malaysia (2018-02-01)

In Vitro Determination Of A Coated Urea Solubility Over Time

Feed quality of ruminant animal can be improved by adding non-protein nitrogen (NPN) sources [8, 5, 3]. Urea is the most common NPN source that used in ruminant nutrition because of its low cost compared with other protein feeds. However, the amount of urea that can be used in ruminant diets is limited. It is due to its rapid hydrolysis and conversion into NH3 which then accumulate in the rumen [11, 10, 9]. The accumulated ammonia is absorbed by rumen wall which in turn can cause toxicity to animal [2, 7]. Therefore, attempts have been made to produce a form of urea that would degrade less rapidly in the rumen, resulting in an increased use of this NPN source in the ration [4, 3, 6]. The objective of this study was to evaluate in vitro solubilization of a polymer-coated urea over 72 hours period. Dried samples of coated and feed grade urea were weighted into 125 ml beakers in duplicate for each time point and then incubated in a 38.8 oC water bath with 100 ml distilled water for 1, 2, 3, 4, 6, 9, 14, 24, 28, 33, 38, 48, 57, and 72 hours period. The contents of each beaker were filtered through a dried weighed filter paper after related incubation times and all the residues were then dried and weighted. The dried residue samples were taken and subjected to analyze for the measurement of their nitrogen content according to the methods of the AOAC [1]. The amounts of solubilized nitrogen from coated urea was then calculated and the percentage solubility was determined at each incubation time. Feed grade urea was solubilized immediately after the addition of distilled water although the release of nitrogen from coated urea was gradually during experimental period (Fig. 1). The rate of solubility at the start of experiment was very high but then reduced and showed a relatively constant rate until 72 hour of incubation. The amount of solubilized urea was 21.3 % after 2 h and then increased by 29 % at 9 h incubation time. About 53.7 % of initial weight of coated urea nitrogen was released at the end of experiment. The results indicated that the coating of urea can change the rate of its solubility and make it as a slow release product that in turn will help to use it at a higher portion with lower risk of toxicity in the diet of ruminant animal. Key words: coated-urea, non-protein nitrogen, ruminant, solubility,
Mohammad Rezaeian