The determination of endogenous urinary nitrogen in protein quality studies with rats

1983 ◽  
Vol 34 (9) ◽  
pp. 957-961 ◽  
Author(s):  
Michael D. Eyre
2021 ◽  
Vol 3 (2) ◽  
pp. 156-162
Author(s):  
T. A. Adegbola ◽  
A. U. Mba ◽  
F. O. Olubajo

FOUR fistulated and four intact West African dwarf Sheep, maintained on hay and concentrate supplements were used for a study of metabolic faecal nitrogen (MEN) endogenous urinary nitrogen (EUN). The composition of the faecal losses was examined. The values obtained enabled calculation of nitrogen requirement of the sheep for maintenance, as well as the value of the experimental rations in the nutrition of the sheep. Values of MFN obtained by two methods were 3.31 and 3.10 g/kg Dry matter (DM) intake. Endogenous urinary nitrogen value was 0.024 g/day per metabolic weight (Wkg0.75.) Analysis of the faeces of the sheep showed that 21.1% of faecal nitrogen (N) were present as microbial and endogenous nitrogen (MEN) and 17.3% was present as water-soluble nitrogen. The biological values (BV) of the rations ranged from 85.7% to 100.0% and the digestibility for maintenance, were 1.20 and 0.41 g/day/Wkg 0.75 during the feeding trials. Values obtained for endogenous N losses and N requirement for low maintenance were low compared with reported values and this may indicate adaptation of the dwarf sheep for survival under inadequate dietary protein supply.


1967 ◽  
Vol 92 (3) ◽  
pp. 357-364 ◽  
Author(s):  
W. G. Bergen ◽  
D. B. Purser ◽  
J. H. Cline

1960 ◽  
Vol 54 (3) ◽  
pp. 329-334 ◽  
Author(s):  
B. N. Majumdar

1. EUN and MFN excretions have been determined in goats on a N-low ration and also on a N-free ration. The values obtained were,EUN = 0·052 g./kg. live weight andMFN = 0·41 g./100 g. dry-matter feed intake.2. The values so determined with the two feeding regimens, for both the EUN and MFN agreed very closely.3. The minimum protein requirement of goats for maintenance, as calculated from the EUN value, is 0·65 lb./1000 lb. live weight.4. The formula for calculating the utilizable protein requirement for this species is found to be P = 0·89. W0.734, and is almost identical with the one given by Mitchell.5. The usefulness of the above formula in predicting the EUN of immature goats is discussed.


1979 ◽  
Vol 41 (1) ◽  
pp. 163-173 ◽  
Author(s):  
H. W. Hulan ◽  
F. G. Proudfoot ◽  
C. G. Zarkadas

1. Squid meal (SqM), produced by grinding and drying the whole squid (Illex illecebrosus) common to the northeast Atlantic and Mediterranean, contained 645 g protein/kg and appeared limiting with respect to lysine, methionine and cystine.2. Although a comparison of the essential amino acid profiles of SqM with other protein concentrates indicated that SqM was higher than fish meal andsoya-beanmeal but lower than casein or whole-egg protein, these tests could not accurately predict protein quality.3. A new approach is reported for evaluating protein quality of SqM. It was based on the direct chromato-graphic determination of its collagen content, from the amounts of 5-hydroxylysine or 5-hydroxyproline present, and elastin, from the amounts of desmosine or iso-desmosine present. This method can alsobe routinely used to assess the connective tissue content and protein quality of animal protein supplements such as fish, meat-and-bone meals.4. A nutritional evaluation of SqM as a source of protein for poultry was carried out using 320 male and 320 female Cobb chicks fed from I-d-old to 48 d, a control diet containing 50 g/kg fish meal or test diets containing 50 g, 100 g or 150 g SqM/kg.5. Feeding of SqM at a rate of up to IOO g/kg diet resulted in optimum biological response and monetary returns.


1979 ◽  
Vol 58 (2) ◽  
pp. 333-336 ◽  
Author(s):  
M.J.D. WALLACE ◽  
G.W. FRONING
Keyword(s):  

2004 ◽  
Vol 53 (3) ◽  
pp. 293-308 ◽  
Author(s):  
J Luo ◽  
A.L Goetsch ◽  
J.E Moore ◽  
Z.B Johnson ◽  
T Sahlu ◽  
...  

1959 ◽  
Vol 37 (11) ◽  
pp. 1351-1360 ◽  
Author(s):  
C. G. Rogers ◽  
J. M. McLaughlan ◽  
D. G. Chapman

Bacteriological methods for the determination of protein quality were evaluated by comparison with protein efficiency ratio (P.E.R.) values determined by a standardized rat growth assay. Enzyme or acid hydrolyzates of foods were used as the source of amino acids with hydrolyzed whole egg powder as the reference standard. With Streptococcus faecalis A.T.C.C. 9790 autolysis occurred in media containing hydrolyzates of proteins deficient in lysine, and was largely responsible for results which did not agree with P.E.R. values. In methods employing Leuconostoc mesenteroides P-60 A.T.C.C. 8042, growth was influenced only by the most limiting amino acid relative to the requirements of the test organism.Results with enzyme hydrolyzates correlated poorly with P.E.R. values, whereas, with acid hydrolyzates, a good correlation was obtained for cereal proteins. A difference in amino acid requirements was largely responsible for the lack of agreement between the P.E.R. assay and methods employing L. mesenteroides, particularly for legumes and foods of animal origin. It was concluded that bacteriological assay methods which have been proposed for protein evaluation are unsatisfactory as screening procedures for the evaluation of protein in foods.


2019 ◽  
Vol 7 (9) ◽  
pp. 2932-2938 ◽  
Author(s):  
James D. House ◽  
Kristen Hill ◽  
Jason Neufeld ◽  
Adam Franczyk ◽  
Matthew G. Nosworthy

1957 ◽  
Vol 37 (2) ◽  
pp. 152-156 ◽  
Author(s):  
H. M. Cunningham ◽  
G. J. Brisson

Daily observations were made on the fecal and urinary nitrogen excretions of four calves fed nitrogen-free diets during the second and fifth weeks after birth. The endogenous urinary nitrogen excretion was equivalent to 65.3 mg. per kg. of body weight (W) per day or 186 mg. per kg. W0.72. The metabolic fecal nitrogen excretion averaged 44.0 mg. per kg. of body weight per day or 0.334 per cent of the dry matter intake.


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