Preliminary Observations on Chemical Changes of Rumen Ingesta with and without Urea

Wegner, M. I.; Booth, A. N.; Bohstedt, G.; Hart, E. B.

doi:10.3168/jds.s0022-0302(41)95383-3

Cited by 26 publications

(10 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In America, confirmation was soon secured, and during the current year the quantitative aspects of these synthetic powers with reference to the utilization of urea as a protein substitute in the ruminant, as contrasted with the nonruminant (107) , has been studied (108,109). At the University of Wisconsin, which had alrea.dy done effective work in this field, Wegner and others (110) have studied the chemical changes that occur in the paunch contents of cattle maintained on rations containing and not containing urea, and the effect of the protein content of the rations on the course of protein synthesis (111). The interpretation of such changes in an organ from which a contintious flow of material, not necessarily repre sentative of the original mixture, is emerging is admittedly difficult.…”

Section: Gi'neral Phases Of Protein Metabolismmentioning

confidence: 94%

The Metabolism of Proteins and Amino Acids

Mitchell¹

1942

Annu. Rev. Biochem.

View full text Add to dashboard Cite

Perhaps the most significant series of investigations on the metab olism of proteins and amino acids, extending into the current year, has been carried out in this country by a group of scientists headed by Rudolf Schoenheimer, whose presence in this country was more a matter of circumstance than of choice. If political intolerance can be said to have any redeeming features, it would be in the enrichment of the intellectual life of those countries not so afflicted, by the en forced migration of scholars of distinction in their chosen fields of study. Among these scholars, Schoenheimer stood pre-eminent. His tragic death on September 11, 1941, must be recorded with sincere regret.The investigations of Schoenheimer and colleagues, involving the use of amino acids and other nitrogenous compounds that had been labeled by the inclusion in their molecules at strategic points of the N15 isotope and of deuterium, permitted a direct attack upon many problems of intermediary metabolism that previously were unsolv able, or that had been incompletely solved by the accumulation merely of indirect or circumstantial evidence. Urinary creatinine was shown indubitably to be derived from tissue creatine, the major mechanism for urea formation was proven to be the ornithine-arginine cycle, the conversion of phenylalanine to tyrosine was found to occur readily 257 Annu. Rev. Biochem. 1942.11:257-282. Downloaded from www.annualreviews.org Access provided by McMaster University on 02/03/15. For personal use only. Quick links to online content Further ANNUAL REVIEWS 258 MITCHELL in the body, even in the presence of an excess of dietary tyrosine, the importance of glutamic and aspartic acids in transamination was es tablished, the conversion of ornithine to proline and glutamic acid was shown to occur, r.nd the anabolic utilization of unnatural isomers by inversion to the natural form was demonstrated with d ( + ) -leucine.Furthermore, new phases in amino acid metabolism were discovered that could only have been suspected previously, such as the irreversi bility of the deamination reaction in volving lysine, as compared with the ready reversibility of the same reaction with leucine, histidine, and many other amino acids. However, the most important discovery of the researches of Schoenheimer and his colleagues with labeled amino acids was the revelation of the existence of a dynamic equilibrium be tween the tissues of the body and the surrounding nutrient media that had not previously been suspected.Schoenheimer & :Kitten berg (1) in a recent review of their work, explain the situation in the following words:The fact that the living organism, in contrast to the dead material, keeps constant the form of the cells and organs as well as the chemical structure of the large molecules has led many investigators to believe that the tissue enzymes, which show their destructive power during autolysis, lie dormant during life and are "activated" only when their functi on is required. The results obtained with isotopes make such a supposition unne...

show abstract

Section: Gi'neral Phases Of Protein Metabolismmentioning

confidence: 94%

The Metabolism of Proteins and Amino Acids

Mitchell¹

1942

Annu. Rev. Biochem.

View full text Add to dashboard Cite

show abstract

“…Other investigators noted that the completion of urea hydrolysis and peak rumen ammonia levels occur in 30 minutes to 2 hours (Wegner et , 1941;Mills et , 1942 ;Matsurooto et , 1958;Ryê et , 1956;Stallcup and Looper, 1958;Le Bars et al, 1957;Holzschuh and Wetterau, 1962;Davis and Stallcup, 1967;Szabd, 1966;Rekib and Sadhu, 1968). Hill et al (1961) reported that 90 to 95% of from ^^C-urea that had been administered intraruminally to goats was lost as expired CO^ in the first 30 to 40 minutes.…”

Section: Ureolysis In the Rumen And Urease Activitymentioning

confidence: 98%

“…Wegner et (1941) reported that when urea was fed the NH^-N in rumen contents increased from 0.075% to 0.222% (75 to 222 mg per 100 ml) within one hour and the liberated ammonia disappeared within 4 to 6 hours. Some of the ammonia appeared in newlysynthesized protein in the rumen.…”

Section: Rumen Ammonia Levels and Assimilation By Rumen Microorganismsmentioning

confidence: 99%

See 1 more Smart Citation

Chemical and metabolic aspects of urea-ammonia toxicosis in cattle and sheep

Lloyd

View full text Add to dashboard Cite

“…Porém, a ureia apresenta rápida taxa de conversão à NH 3 , observada por Wegner et al (1941) Zinco 3400 1700 1700 1700 1700 Manganês 2040 1020 1020 1020 1020 Selênio 17 9 9 9 9 Cobalto 61 31 31 31 31 Iodo 61 31 31 31 31 Flavomicina --100 -100 SM -Suplemento mineral; SPU -Suplemento proteico com ureia; SPUF -Suplemento proteico com ureia e flavomicina; SPM -Suplemento proteico com mistura de ureia comum e ureia protegida; SPMF -Suplemento proteico com mistura de ureia comum e ureia protegida e flavomicina; NNP -Nitrogênio não proteico; PB -Proteína bruta. 1 Mistura de farelo de trigo, glúten de milho e milho moído.…”

Section: Ureia Protegida -Optigen ®unclassified

Flavomicina e ureia protegida na suplementação de novilhas em pastagem diferida de capim-marandu

Sanchez¹

View full text Add to dashboard Cite

pela confiança e determinação na função de orientador. Também pela confiança e amizade depositadas em mim durante todo o período em que estive sob sua orientação. À Universidade de São Paulo e a Coordenação de Aperfeiçoamento de Pessoal de Nível Superior -CAPES, pela oportunidade de cursar o mestrado e pela bolsa que me foi consedida. Aos zootecnistas Fabio Locci Gomes e Talita Freitas pela ajuda durante a realização da parte de campo do experimento. Às empresas Alltech ® do Brasil e Nutron ® , nas pessoas do Dr. Marcelo de Queiros Manella e da zootecnista Grasiela da Silva, pela colaboração financeira e na elaboração do projeto. Prof. Dr. César Gonçalves de Lima, pela colaboração nas análises estatísticas envolvidas neste projeto. , e todos os alunos de graduação e pós graduação, professores e funcionários que atuam no Grupo das Ciências Agrárias pela amizade e ajuda com as quais pude contar. Aos moradores da República Pantaneira, Fernando Boi, Diogo, Marcelo Maysa, Felipe Fininho, Luciano Panga, pelos anos de convívio e amizade. Aos amigos Cesar O. Rocha e Fábio C. L. Oliveira pela moradia e experiências trocadas durante o convívio no último ano de meu mestrado. À Thaís Brochado, minha namorada, pelo constante incentivo e ajuda durante esta etapa de minha vida.EPÍGRAFE "Sábio é aquele que conhece os limites da própria ignorância". Sócrates RESUMO SANCHEZ, J. M. D. Flavomicina e ureia protegida na suplementação de novilhas em pastagem diferida de capim-marandu. 2014. 76 f. DissertaçãoO uso de aditivos alimentares promotores de crescimento em bovinos de corte tem aumentado, porém, existem relativamente poucos estudos sobre uso de aditivos para bovinos em pastagem. Objetivou-se avaliar o efeito de flavomicina (FL) e uma mistura de ureia comum e ureia protegida no desempenho (GMD), produtividade (GA) e consumo de suplemento (CS) por novilhas em pastagem diferida de capim-marandu (Brachiaria brizantha cv. Marandu), de julho a novembro de 2010. O delineamento experimental foi em blocos completos casualizados, com cinco tratamentos e três repetições, arranjados num fatorial 2x2, mais um tratamento controle (suplemento mineral). Os fatores foram a inclusão de FL e a fonte de nitrogênio não proteico (NNP), adicionados a um suplemento proteico. O fator FL foi avaliado nos níveis de inclusão 0 e 100 mg kg -1 de suplemento. Foram avaliadas duas fontes de NNP: ureia comum (U) e uma mistura (M) de ureia comum (2/3 do NNP) e ureia protegida (1/3 do NNP), ambas fornecendo 365 g kg -1 de equivalente proteico ao suplemento. Foram utilizadas 120 novilhas da raça Nelore, peso médio de 206 kg, distribuídas em 15 unidades experimentais. As variáveis resposta da forragem foram massa de forragem, oferta de forragem, composição morfológica e concentração de PB, FDN e FDA. Os animais foram manejados em lotação rotativa, com 7 dias de ocupação e 28 dias de descanso, usando taxa de lotação variável para se chegar a ofertas de forragem semelhante entre tratamentos. Os animais do tratamento controle tiveram o menor GMD (-0,054 kg de peso vi...

show abstract

Preliminary Observations on Chemical Changes of Rumen Ingesta with and without Urea

Cited by 26 publications

References 2 publications

The Metabolism of Proteins and Amino Acids

The Metabolism of Proteins and Amino Acids

Chemical and metabolic aspects of urea-ammonia toxicosis in cattle and sheep

Flavomicina e ureia protegida na suplementação de novilhas em pastagem diferida de capim-marandu

Contact Info

Product

Resources

About