Urea/Ammonia Metabolism in the Rumen and Toxicity in Ruminants

Patra, Amlan Kumar

doi:10.1007/978-81-322-2401-3_22

Cited by 38 publications

(36 citation statements)

References 69 publications

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“…Straws were either untreated (control) or pretreated with (i) urea at 40 g kg −1 dry matter (DM), or (ii) urea and ammonium nitrate (urea+nitrate) at 34 and 6 g kg −1 DM (nitrate was supplied at 4.7 g kg −1 DM), respectively. High doses of urea and nitrate supplementation are recognized to be toxic to the host animals . Studies indicate that feeding dairy cattle with urea‐treated rice straw (30–55 g kg −1 DM) increases nutrient digestibility without any toxicity symptoms .…”

Section: Methodsmentioning

confidence: 99%

“…High doses of urea and nitrate supplementation are recognized to be toxic to the host animals. 10,11 Studies indicate that feeding dairy cattle with urea-treated rice straw (30-55 g kg −1 DM) increases nutrient digestibility without any toxicity symptoms. 12,13 Lee et al 14 reported that nitrate supplementation at 9 g kg −1 DM decreased methane production without any signs of toxicity in beef heifers.…”

Section: Sample Collection and Pretreatment Proceduresmentioning

confidence: 99%

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Urea plus nitrate pretreatment of rice and wheat straws enhances degradation and reduces methane production inin vitroruminal culture

Zhang

Wang

et al. 2018

J Sci Food Agric

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Section: Methodsmentioning

confidence: 99%

Section: Sample Collection and Pretreatment Proceduresmentioning

confidence: 99%

Urea plus nitrate pretreatment of rice and wheat straws enhances degradation and reduces methane production inin vitroruminal culture

Zhang

Wang

et al. 2018

J Sci Food Agric

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“…Therefore, the rumen microbiota are a key factor affecting protein utilization efficiency. The released ammonia in the rumen can be absorbed across the epithelium into the liver and then detoxified to urea, which is then recycled into the rumen and rapidly hydrolyzed to ammonia by ureases from ureolytic bacteria (Patra, 2015;Jin et al, 2017). Therefore, urea is not only a cost effective non-protein nitrogen (NPN) source that provides ammonia, which is obligately required by the fiber-digesting bacteria, but also acts a chemical component that can be measured to study the mechanisms underlying NPN metabolism by the rumen microbiota.…”

Section: Introductionmentioning

confidence: 99%

Changes in the Solid-, Liquid-, and Epithelium-Associated Bacterial Communities in the Rumen of Hu Lambs in Response to Dietary Urea Supplementation

et al. 2020

Front. Microbiol.

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Frontiers in Microbiology | www.frontiersin.org February 2020 | Volume 11 | Article 244 Li et al.Urea Affects Rumen Bacteiral Communities epithelial fraction of the UC and LU treatments relative to HU treatment. Comparisons of predictive function in the rumen solid, liquid, and epithelial fractions among the three treatments also revealed differences. Collectively, these results reveal the change of the rumen bacterial community to dietary urea supplementation.

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“…In the rumen, ureolytic bacteria produce urease to hydrolyze urea to ammonia, which is subsequently used for the synthesis of amino acids and microbial protein. Normally, the rate of urea hydrolysis exceeds the rate of ammonia utilization, which leads to poor efficiency of urea utilization in the rumen and explosion of toxic ammonia in the blood (Patra, 2015 ). Acetohydroxamic acid (AHA), an inhibitor of urease activity that prevents the rapid hydrolysis of urea and consequent explosion of ammonia in rumen, is commonly applied in the rations of ruminants (Upadhyay, 2012 ).…”

Section: Introductionmentioning

confidence: 99%

Insights into Abundant Rumen Ureolytic Bacterial Community Using Rumen Simulation System

et al. 2016

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Urea, a non-protein nitrogen for dairy cows, is rapidly hydrolyzed to ammonia by urease produced by ureolytic bacteria in the rumen, and the ammonia is used as nitrogen for rumen bacterial growth. However, there is limited knowledge with regard to the ureolytic bacteria community in the rumen. To explore the ruminal ureolytic bacterial community, urea, or acetohydroxamic acid (AHA, an inhibitor of urea hydrolysis) were supplemented into the rumen simulation systems. The bacterial 16S rRNA genes were sequenced by Miseq high-throughput sequencing and used to reveal the ureoltyic bacteria by comparing different treatments. The results revealed that urea supplementation significantly increased the ammonia concentration, and AHA addition inhibited urea hydrolysis. Urea supplementation significantly increased the richness of bacterial community and the proportion of ureC genes. The composition of bacterial community following urea or AHA supplementation showed no significant difference compared to the groups without supplementation. The abundance of Bacillus and unclassified Succinivibrionaceae increased significantly following urea supplementation. Pseudomonas, Haemophilus, Neisseria, Streptococcus, and Actinomyces exhibited a positive response to urea supplementation and a negative response to AHA addition. Results retrieved from the NCBI protein database and publications confirmed that the representative bacteria in these genera mentioned above had urease genes or urease activities. Therefore, the rumen ureolytic bacteria were abundant in the genera of Pseudomonas, Haemophilus, Neisseria, Streptococcus, Actinomyces, Bacillus, and unclassified Succinivibrionaceae. Insights into abundant rumen ureolytic bacteria provide the regulation targets to mitigate urea hydrolysis and increase efficiency of urea nitrogen utilization in ruminants.

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Urea/Ammonia Metabolism in the Rumen and Toxicity in Ruminants

Cited by 38 publications

References 69 publications

Urea plus nitrate pretreatment of rice and wheat straws enhances degradation and reduces methane production inin vitroruminal culture

Urea plus nitrate pretreatment of rice and wheat straws enhances degradation and reduces methane production inin vitroruminal culture

Changes in the Solid-, Liquid-, and Epithelium-Associated Bacterial Communities in the Rumen of Hu Lambs in Response to Dietary Urea Supplementation

Insights into Abundant Rumen Ureolytic Bacterial Community Using Rumen Simulation System

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