In vivo rat assay for true protein digestibility: collaborative study.
Eight laboratories participated in a collaborative study to estimate precision of a standardized rat assay for determining true protein digestibility in selected animal, fish, and cereal products. Each of 7 test protein sources (casein, tuna fish, macaroni/cheese, pea protein concentrate, rolled oats, pinto beans, and nonfat dried milk) was fed as the sole source of protein at a 10% protein level in mixed diets. Each diet was fed to 2 replicate groups of 4 rats each for a 4-day acclimation period and a 5-day balance period. Mean digestibilities ranged from 98.6% for casein to 72.6% for pinto beans. Repeatability standard deviations ranged from 0.5 to 2.0%; the mean relative standard deviation for repeatability was 0.9% (range 0.5-2.8%). Reproducibility standard deviations ranged from 1.2 to 3.2%, and the mean relative standard deviation for reproducibility was 2.4% (range 1.3-4.4%). The method has been approved interim official first action for determining true protein digestibility in foods and ingredients.
McDonough
F E
FE
U.S. Department of Agriculture, Beltsville Human Nutrition Research Center, MD 20705.
Steinke
F H
FH
Sarwar
G
G
Eggum
B O
BO
Bressani
R
R
Huth
P J
PJ
Barbeau
W E
WE
Mitchell
G V
GV
Phillips
J G
JG
D000818:Animals; D001681:Biological Assay; D004032:Diet; D004044:Dietary Proteins / Q000032:analysis / Q000378:metabolism*; D004063:Digestion / Q000502:physiology*; D007202:Indicators and Reagents; D008297:Male; D009584:Nitrogen / Q000032:analysis; D051381:Rats; D011919:Rats, Inbred Strains
D004044:Dietary Proteins; D007202:Indicators and Reagents; D009584:Nitrogen