Net protein utilization

Net protein utilization (NPU) = %digestibility (D) x biological value(BV) complete utilization = 100. Biological value is given in parentheses ... 

Alternate Protocol 4 Net Protein Utilization (NPU) and Biological Value... 

Net protein ratio (NPR) is used to correct PER values for the amount of protein required for cell maintenance. NPR is often run in conjunction with a PER. The experiment requires that one additional set of animals be added as a treatment group. This group of animals is fed a basal diet with no protein (zero protein or basal diet). Results from RNPR are similar to net protein utilization (NPU) and biological value (BV methods, see Alternate Protocol 4). A 2-week RNPR is thought to be the most appropriate rat test for routine assessment of protein quality. 

Calculate the net protein utilization (NPU), which is the proportion of nitrogen intake that is retained as is equivalent to BV x true digestibility, by comparing the carcass nitrogen content of a group of animals fed the test-protein diet to that of animals fed a zero-protein diet ... 

Nutrition Effect of Protein-Bound Methionine Sulfoxide. There is some discrepancy in the results concerning the biological availability of protein-bound methionine sulfoxide. Ellinger and Palmer (71) found that oxidized casein had a lower NPU (Net Protein Utilization) than normal casein. Slump and Schreuder (72) concluded that there was a positive biological availability of peptide-bound methionine sulfoxide. 

The quality of different proteins can be expressed according to their chemical score, protein efficiency ratio (PER), biological value (BV), and net protein utilization (NPU). These parameters refer to the different tests used to define the protein s quality. The chemical score refers only to the property of the protein in question. The PER, BV, and NPU refer to relationship.s between the dietary protein and the consumer. The values of the PER, BV, and NPU depend on properties of both the protein in question and the needs of the animal. The chemical score, PER, BV, and NPU of proteins in various foods, including eggs, fish, rice, and maize, are listed in Table 8,1 3. 

In 1969, deGroot and Slump also demonstrated decreases for in vitro digestibility of alkali-treated soy protein Isolate and decreases In absorption of some amino acids by everted Intestinal sacs (14). These workers also observed decreases In net protein utilization for treated soybean meal, treated soy protein Isolate and treated casein. These decreases In net protein utilization were correlated with Increases In LAL formation. In these experiments, therefore. It was possible that protein utilization was hindered by the presence of LAL. 

Several changes which can adversely influence the nutritional quality occur in proteins that are subjected to severe alkaline treatments. Losses in the amino acids (lysine and cystine, particularly), drops in digestibility, and reduction in net protein utilization all increase as the severity of the alkaline treatment increases ( ). Increases in either temperature or pH of treatment caused similar results. Decreased intestinal absorption amino acids was attributed to LAL-like cross-links and racemization. Kraus and Schmidt (68) also observed a reduction in digestibility of milk proteins as treatment temperature increased from 30 to 90°C at pH 12. 

The net protein utilization, or NPU, is the ratio of amino acid converted to proteins to the ratio of amino acids supplied. This figure is somewhat affected by the salvage of essential amino acids within the body, but is profoundly affected by the level of limiting amino acids within a food [125]. 

Mohammed H. Rahman, Iqbal Hossain, and Moslehuddin, Nutritional evaluation of sweet lupin (Lupinus angustifolius) Net protein utilization (NPU) nitrogen balance and fractionation studies. Br. J. Nutr. 77(03) 443-157, March 1997. 

Protein, as well as nonprotein energy (i.e., carbohydrates and fats), must be provided in sufficient amounts to drive protein synthesis and prevent protein-energy deficiency [18]. However, too many nonprotein calories will inCTease weight but not lean body mass, which may be the case in certain patients with inherited metabohc disorders on low protein, high caloric intakes. The type of nonprotein energy can make a difference on protein status. Studies have indicated that carbohydrate (CHO), and not fat, can rednce postprandial protein degradation [19,20]. Net protein utilization improved by 5 % and nitrogen retention by 14 % when carbohydrate was offered. Excess CHO withont protein stimulates post-absorptive proteolysis and protein synthesis [21],... 

Monchi M, R at AA. Comparison of net protein utilization of milk protein mild enzymatic hydrolysates and free amino acid mixtures with a close pattern in the rat. JPEN J Parenter Enteral Nutr. 1993 17(4) 355-63. 

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